U.S. patent application number 10/212897 was filed with the patent office on 2003-01-02 for method of use of monomeric insulin as a means for improving the reproducibility of inhaled insulin.
Invention is credited to Farr, Stephen J., Gonda, Igor, Rubsamen, Reid M..
Application Number | 20030000519 10/212897 |
Document ID | / |
Family ID | 27567336 |
Filed Date | 2003-01-02 |
United States Patent
Application |
20030000519 |
Kind Code |
A1 |
Gonda, Igor ; et
al. |
January 2, 2003 |
Method of use of monomeric insulin as a means for improving the
reproducibility of inhaled insulin
Abstract
The need for the delivery of insulin by injection can be reduced
or eliminated by delivering an aerosolized monomeric insulin
formulation. Repeatability of dosing and more particularly the
repeatability of the blood concentration versus time profile is
improved relative to regular insulin. The blood concentration
versus time profile is substantially unaffected by specific aspects
of the patient's breathing maneuver at delivery. Further, the rate
at which blood glucose is lowered is increased by the use of
monomeric insulin. Particles of insulin and in particular monomeric
insulin delivered to the surface of lung tissue will be absorbed
into the circulatory system. The monomeric insulin may be a dry
powder but is preferably in a liquid formulation delivered to the
patient from a hand-held, self-contained device which automatically
releases an aerosolized burst of formulation. The device includes a
sensor which is preferably electronic which measures inspiratory
flow and volume which measurement can be used to control the point
of drug release.
Inventors: |
Gonda, Igor; (San Francisco,
CA) ; Rubsamen, Reid M.; (Oakland, CA) ; Farr,
Stephen J.; (Orinda, CA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
200 MIDDLEFIELD RD
SUITE 200
MENLO PARK
CA
94025
US
|
Family ID: |
27567336 |
Appl. No.: |
10/212897 |
Filed: |
August 5, 2002 |
Related U.S. Patent Documents
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Application
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Filing Date |
Patent Number |
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10212897 |
Aug 5, 2002 |
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09975085 |
Oct 9, 2001 |
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6431167 |
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09975085 |
Oct 9, 2001 |
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09888094 |
Jun 21, 2001 |
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6427681 |
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09888094 |
Jun 21, 2001 |
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09656535 |
Sep 7, 2000 |
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6250298 |
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09656535 |
Sep 7, 2000 |
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09004756 |
Jan 8, 1998 |
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6131567 |
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09004756 |
Jan 8, 1998 |
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08792616 |
Jan 31, 1997 |
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5888477 |
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08792616 |
Jan 31, 1997 |
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08754423 |
Nov 22, 1996 |
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5743250 |
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08754423 |
Nov 22, 1996 |
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08549343 |
Oct 27, 1995 |
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5915378 |
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08549343 |
Oct 27, 1995 |
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08331056 |
Oct 28, 1994 |
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5672581 |
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08331056 |
Oct 28, 1994 |
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08011281 |
Jan 29, 1993 |
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5364838 |
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Current U.S.
Class: |
128/200.14 ;
128/203.12 |
Current CPC
Class: |
A61M 15/0065 20130101;
A61K 9/0075 20130101; A61M 15/0085 20130101; A61J 7/0418 20150501;
A61J 7/0445 20150501; A61M 15/008 20140204; A61M 2016/0036
20130101; A61M 15/0045 20130101; A61J 7/0427 20150501; A61M 15/0031
20140204; A61M 2205/8206 20130101; A61M 15/0066 20140204; A61K
9/007 20130101; A61M 15/0051 20140204; A61M 16/142 20140204; A61K
9/0073 20130101; A61M 11/001 20140204; A61K 38/28 20130101; A61M
15/009 20130101; A61M 2016/0021 20130101; A61M 15/00 20130101; A61M
2202/064 20130101; A61M 2202/062 20130101; A61M 2205/50
20130101 |
Class at
Publication: |
128/200.14 ;
128/203.12 |
International
Class: |
A61M 011/00; A61M
015/00; A61M 016/10 |
Claims
1. A method of improving reproducibility of insulin delivered by
inhalation, comprising: aerosolizing a formulation comprising
monomeric insulin; inhaling the aerosolized formulation into the
lung of a patient in need of insulin in a manner which allows the
particles of the insulin to deposit on the lung tissue.
2. The method of claim 1, wherein the insulin is insulin
lispro.
3. The method of claim 1, further comprising: measuring the
patient's glucose level.
4. The method of claim 3, further comprising: repeating the
aerosolizing, inhaling and measuring in a manner so as to maintain
the patients glucose level in a desired range.
5. The method of claim 4, wherein each aerosolizing is carried out
to create an aerosolized dose containing substantially the same
amount of insulin.
6. The method of claim 5, wherein the inhaling is carried out with
different inhaled volumes of air while maintaining essentially the
same blood concentration versus time profile in term of affect on
glucose level.
7. A method of maintaining a diabetic patient's blood glucose level
within a desired range, comprising: administering monomeric insulin
to the patient by inhalation.
8. The method of claim 10, wherein the monomeric insulin is insulin
lispro.
9. The method of claim 7, further comprising: orally administering
a sulfonylurea drug to the patient.
10. The method of claim 9, wherein the sulfonylurea drug is
selected from the group consisting of acetohexamide,
chlorpropamide, tolazamide, tolbutamide, glipzide and
glyburide.
11. A method of enhancing the rate at which an inhaled drug
migrates into a patient's circulatory system, comprising:
aerosolizing a formulation comprised of a monomeric insulin;
inhaling the aerosolized formulation into lungs of a patient and
allowing particles of the monomeric insulin to deposit on lung
tissue.
12. The method of claim 11, wherein the monomeric insulin is
insulin lispro.
13. The method of claim 11, further comprising: heating air
surrounding the aerosolized formulation.
14. The method of claim 11, wherein the aerosol comprises particles
having a diameter in the range of about 1.0 to about 4.0
microns.
15. The method of claim 11, further comprising: repeating the
aerosolizing and inhaling a plurality of times.
16. The method of claim 15, wherein the formulation is aerosolized
by being forced through a porous membrane from a disposable
container.
17. The method of claim 1, wherein the formulation is a liquid
formulation comprised of a pharmaceutically acceptable carrier and
insulin lispro and is present in the container; and wherein the
pores have a cross-sectional configuration with a small end opening
of 0.25 to 6.0 microns in diameter and a large end opening of 2 to
20 times the diameter of the small end.
18. A method of aerosolized insulin delivery comprising:
aerosolizing a formulation comprising insulin; inhaling the aerosol
with a volume of air; measuring the inhaled volume of air; and
providing a signal when the inhaled volume reaches 80% or more of
lung capacity of the lungs of an inhaling patient.
19. The method of claim 18, further comprising: repeating the
aerosolizing, inhaling and measuring a plurality of times while
obtaining substantially the same total inhaled volume for each
delivery.
20. The method of claim 19, wherein the aerosolizing and inhaling
are repeatedly carried out at substantially the same inspiratory
flow rate and inspiratory volume.
Description
CROSS-REFERENCES
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 08/792,616 filed Jan. 31, 1997 which
application is incorporation herein by reference and to which
application we claim priority under 35 U.S.C. .sctn.120.
FIELD OF THE INVENTION
[0002] This invention relates generally to a method of aerosolized
drug delivery. More specifically, this invention relates to the
controlled intrapulmonary delivery of a monomeric insulin alone or
in combination with other treatment methodologies which are
combined to significantly reduce or eliminate the need for
administering insulin by injection.
BACKGROUND OF THE INVENTION
[0003] Diabetes Mellitus is a disease affecting approximately 7.5
million people in the United States. The underlying cause of this
disease is diminished or absent insulin production by the Islets of
Langerhans in the pancreas. Of the 7.5 million diagnosed diabetics
in the United States, approximately one-third are treated using
insulin replacement therapy. Those patients receiving insulin
typically self-administer one or more doses of the drug per day by
subcutaneous injection. Insulin is a polypeptide with a nominal
molecular weight of 6,000 Daltons. Insulin has traditionally been
produced by processing pig and cow pancreas to allow isolation of
the natural product. More recently, recombinant technology has made
it possible to produce human insulin in vitro. It is the currently
common practice in the United States to institute the use of
recombinant human insulin in all of those patients beginning
insulin therapy.
[0004] It is known that most proteins are rapidly degraded in the
acidic environment of the GI tract. Since insulin is a protein
which is readily degraded in the GI tract, those in need of the
administration of insulin administer the drug by subcutaneous
injection (SC). No satisfactory method of orally administering
insulin has been developed. The lack of such an oral delivery
formulation for insulin creates a problem in that the
administration of drugs by injection can be both psychologically
and physically painful.
[0005] In an effort to provide for a non-invasive means for
administering insulin, and thereby eliminate the need for
hypodermic syringes, aerosolized insulin formulations have been
tested. Aerosolized insulin formulations have been shown to produce
insulin blood levels in man when these aerosols are introduced onto
nasal or pulmonary membrane. Moses et al. [Diabetes, Vol. 32,
November 1983] demonstrated that a hypoglycemic response could be
produced following nasal administration of 0.5 units/kg.
Significant inter-subject variability was noted, and the nasal
insulin formulation included unconjugated bile salts to promote
nasal membrane penetration of the drug. Salzman et al. [New England
Journal of Medicine, Vol. 312, No. 17] demonstrated that an
intranasal aerosolized insulin formulation containing a non-ionic
detergent membrane penetration enhancer was effective in producing
a hypoglycemic response in diabetic volunteers. Their work
demonstrated that nasal irritation was present in varying degrees
among the patients studied. In that diabetes is a chronic disease
which must be continuously treated by the administration of insulin
and in that mucosal irritation tends to increase with repeated
exposures to the membrane penetration enhancers, efforts at
developing a non-invasive means of administering insulin via nasal
administration have not been commercialized.
[0006] In 1971, Wigley et al. [Diabetes, Vol 20, No. 8]
demonstrated that a hypoglycemic response could be observed in
patients inhaling an aqueous formulation of insulin into the lung.
Radio-immuno assay techniques demonstrated that approximately 10
percent of the inhaled insulin was recovered in the blood of the
subjects. Because the surface area of membranes available to absorb
insulin is much greater in the lung than in the nose, no membrane
penetration enhancers are required for delivery of insulin to the
lungs by inhalation. The inefficiency of delivery seen by Wigley
was greatly improved in 1979 by Yoshida et al. [Journal of
Pharmaceutical Sciences, Vol. 68, No. 5] who showed that almost 40
percent of insulin delivered directly into the trachea of rabbits
was absorbed into the bloodstream via the respiratory tract. Both
Wigley and Yoshida showed that insulin delivered by inhalation
could be seen in the bloodstream for two or more hours following
inhalation.
[0007] Aerosolized insulin therefore can be effectively given if
the aerosol is appropriately delivered into the lung. In a review
article, Dieter Kohler [Lung, supplement pp. 677-684] remarked in
1990 that multiple studies have shown that aerosolized insulin can
be delivered into and absorbed from the lung with an expected
absorption half-life of 15-25 minutes. However, he comments that
"the poor reproducibility of the inhaled dose [of insulin] was
always the reason for terminating these experiments." This is an
important point in that the lack of precise reproducibility with
respect to the administration of insulin is critical. The problems
associated with the inefficient administration of insulin cannot be
compensated for by administering excess amounts of the drug in that
the accidental administration of too much insulin could be
fatal.
[0008] Effective use of an appropriate nebulizer can achieve high
efficiency in delivering insulin to human subjects. Laube et al.
[Journal of Aerosol Medicine, Vol. 4, No. 3, 1991] have shown that
aerosolized insulin delivered from a jet nebulizer with a mass
median aerodynamic diameter of 1.12 microns, inhaled via a holding
chamber at a slow inspiratory flow rate of 17 liters/minute,
produced an effective hypoglycemic response in test subjects at a
dose of 0.2 units/kg. Colthorpe et al. [Pharmaceutical Research,
Vol. 9, No. 6, 1992] have shown that aerosolized insulin given
peripherally into the lung of rabbits produces a blood
concentration versus time profile of over 50 percent in contrast to
5.6 percent blood concentration versus time profile seen for liquid
insulin dripped onto the central airways. Colthorpe's work supports
the contention that aerosolized insulin must be delivered
peripherally into the lung for maximum efficiency and that
inadvertent central deposition of inhaled aerosolized insulin will
produce an effect ten times lower than that desired. Variations in
dosing of 10-fold are clearly unacceptable with respect to the
administration of most drugs, and in particular, with respect to
the administration of insulin.
[0009] The present invention endeavors to provide a non-invasive
methodology for enhancing treatment of diabetic patients via
aerosolized delivery.
SUMMARY OF THE INVENTION
[0010] Aerosolized delivery of insulin is disclosed wherein the
insulin is monomeric insulin. Aerosolized delivery of monomeric
insulin is significantly less affected by an inhaling patient's
breathing pattern as compared to the effect on conventional
recombinant insulin. More specifically, the maximum insulin
concentration (C.sub.MAX) and the time needed to obtain the maximum
concentration (T.sub.MAX) is much less affected by the amount of
air inhaled after delivery of aerosolized drug. Accordingly, a
higher degree of repeatability of dosing can be obtained (with
monomeric insulin as compared to regular insulin) making it
substantially more practical for patients to control glucose levels
by inhaling insulin-thereby making diabetics less dependent on
injecting insulin.
[0011] When delivering aerosolized insulin the patient can be
coached (by teaching and/or by the device which measures flow rate
and/or volume) to inhale at a given rate and to inhale a given
amount of air (before and after the aerosol is released). One of
the findings disclosed here is that the inhaled volume at delivery
does not substantially affect the blood concentration versus time
profile for the aerosolized delivery of monomeric insulin. However,
the inhaled volume at delivery does substantially affect the blood
concentration versus time profile of regular insulin. Accordingly,
one aspect of the invention is the aerosolized delivery of
monomeric insulin without regard to respiratory maneuver parameters
such as inhaled volume. A second aspect of the invention is
aerosolized delivery of insulin which is not monomeric insulin
while measuring inhaled volume and insuring that the inhaled volume
is (1) repeated for each dose in the same amount and (2) preferably
a large inhaled volume, e.g. 80% or more of the lung capacity of
the patient. It should be noted that to obtain the most repeatable
results that monomeric insulin should be delivered each time at
substantially the same inspiratory flow rate and inspiratory volume
at delivery and such delivery should be followed by the same
inhaled volume which is preferably a maximum inhaled volume.
[0012] The monomeric insulin formulation may be in any form, e.g.,
a dry powder, or dispersed or dissolved in a low boiling point
propellant. However, the formulation is more preferably an aqueous
solution having a pH close to 7.4.+-.1.0 which can be aerosolized
into particles having a particle diameter in the range of about 1.0
to about 4.0 microns. Formulations of monomeric insulin are
preferably aerosolized and administered via hand-held,
self-contained devices which are automatically actuated at the same
release point in a patient's inspiratory flow cycle. The release
point is automatically determined either mechanically or, more
preferably calculated by a microprocessor which receives data from
a sensor making it possible to determine inspiratory flow rate and
inspiratory volume. The device can measure parameters including
inspiratory flow rates and volumes and provide information to the
patient which can aid in controlling the patient's respiratory
maneuvers. Preferably the device is loaded with a cassette
comprised of an outer housing which holds a package of individual
disposable collapsible containers of a monomeric insulin analog
containing formulation for systemic delivery. Actuation of the
device forces the monomeric insulin formulation through a porous
membrane of the container which membrane has pores having a
diameter in the range of about 0.25 to 3.0 microns, preferably 0.25
to 1.5 microns. The porous membrane is positioned in alignment with
a surface of a channel through which a patient inhales air.
[0013] The dose of insulin analog to be delivered to the patient
varies with a number of factors--most importantly the patient's
blood glucose level. Thus, the device can deliver all or any
proportional amount of the formulation present in the container. If
only part of the contents are aerosolized the remainder may be
discarded. By delivering any proportional amount of a container the
patient can adjust the dose to any desired level while using
containers which all contain the same amount of monomeric
insulin.
[0014] Smaller particle sizes are preferred to obtain systemic
delivery of insulin analog. Thus, in one embodiment, after the
aerosolized mist is released into the channel the air surrounding
the particles may be heated in an amount sufficient to evaporate
carrier and thereby reduce particle size. The air drawn into the
device can be actively heated by moving the air through a heating
element which element is pre-heated prior to the beginning of a
patient's inhalation. The amount of energy added can be adjusted
depending on factors such as the desired particle size, the amount
of the carrier to be evaporated, the water vapor content of the
surrounding air and the composition of the carrier (see U.S. Pat.
No. 5,522,385 issued Jun. 4, 1996).
[0015] To obtain systemic delivery it is desirable to get the
aerosolized formulation deeply into the lung. This is obtained, in
part, by adjusting particle sizes. Particle diameter size is
generally about one to three times the diameter of the pore from
which the particle is extruded In that it is technically difficult
to make pores of 1.0 microns or less in diameter the use of
evaporation can reduce particle size to 3.0 microns or less even
with pore sizes well above 1 micron. Energy may be added in an
amount sufficient to evaporate all or substantially all carrier and
thereby provide particles of dry powdered insulin or highly
concentrated insulin formulation to a patient which particles are
uniform in size regardless of the surrounding humidity and smaller
due to the evaporation of the carrier.
[0016] In addition to adjusting particle size, systemic delivery of
insulin is obtained by releasing an aerosolized dose at a desired
point in a patient's respiratory cycle. When providing systemic
delivery it is important that the delivery be reproducible.
[0017] Reproducible dosing of insulin to the patient is obtained
by: (1) using monomeric insulin which has been shown here to be
less affected by the patient's respiratory pattern, and/or;
(2)providing for automatic release of formulation in response to a
determined inspiratory flow rate and measured inspiratory volume.
The automatic release method involves measuring for, determining
and/or calculating a firing point or drug release decision based on
instantaneously (or real time) calculated, measured and/or
determined inspiratory flow rate and inspiratory volume points. To
obtain repeatability in dosing, the formulation is repeatedly
released at the same measured (1) inspiratory flow rate and (2)
inspiratory volume. To maximize the efficiency of delivery aerosols
are released at (3) a measured inspiratory flow rate in the range
of from about 0.1 to about 2.0 liters/second and (2) a measured
inspiratory volume in the range of about 0.1 to about 1.5 liters.
After the aerosol is released the patient preferably continues
inhaling to a maximum inhalation point.
[0018] A primary object of the invention is to provide for a method
of increasing the repeatability at which glucose levels can be
controlled by aerosol delivery of monomeric insulin.
[0019] An advantage of the invention is that the aerosolized
delivery of monomeric insulin is substantially less affected by a
patient's breathing maneuvers during delivery as compared to
regular insulin and specifically is less affected by how much the
patient inhales after aerosolized delivery.
[0020] A feature of the invention is the commercially available
insulin lispro can be used in the method.
[0021] Another object is to provide a method of administering a
monomeric insulin analog formulation to a patient wherein the
formulation is repeatedly delivered to a patient at the same
measured inspiratory flow rate (in the range of 0.1 to 2.0
liters/second) and separately determined inspiratory volume
(beginning delivery in the range of 0.15 to 1.5 liters and
continuing inspiration to maximum, e.g., 4-5 liters).
[0022] Another object of the invention is to combine delivery
therapies for inhaling monomeric insulin with monitoring
technologies so as to maintain tight control over the serum glucose
level of a patient suffering from diabetes mellitus.
[0023] Another object of the invention is to provide a device which
allows for the intrapulmonary delivery of controlled amounts of
monomeric insulin formulation based on the particular needs of the
diabetic patient including serum glucose levels and insulin
sensitivity.
[0024] Another object of the invention is to provide a means for
treating diabetes mellitus which involves supplementing monomeric
insulin administration using an intrapulmonary delivery means in
combination with injections of insulin and/or oral hypoglycemic
agents such as sulfonylureas.
[0025] Another advantage of the present invention is that the
methodology allows the administration of a range of different size
doses of monomeric insulin by a convenient and painless route, thus
decreasing the probability of insulin overdosing and increasing the
probability of safely maintaining desired serum glucose levels.
[0026] Another feature of the device of the present invention is
that it may be programmed to provide variable dosing (from the same
size container) so that different doses are delivered to the
patient at different times of the day coordinated with meals and/or
other factors important to maintain proper serum glucose levels
with the particular patient.
[0027] Another feature of the invention is that the portable,
hand-held inhalation device of the invention can be used in
combination with a portable device for measuring serum glucose
levels in order to closely monitor and titrate dosing based on
actual glucose levels.
[0028] Yet another feature of the invention is that the
microprocessor of the delivery device can be programmed to prevent
overdosing by preventing formulation release more than a given
number of times within a given period of time.
[0029] Another object of the invention is to adjust particle size
by heating air surrounding the particles in an amount sufficient to
evaporate carrier and reduce total particle size.
[0030] Another object is to provide a drug delivery device which
includes a desiccator for drying air in a manner so as to remove
water vapor and thereby provide consistent particle sizes even when
the surrounding humidity varies.
[0031] Another object is to provide a device for the delivery of
aerosols which measures humidity via a solid state hygrometer.
[0032] A feature of the invention is that drug can be dispersed or
dissolved in a liquid carrier such as water and dispersed to a
patient as dry or substantially dry particles of monomeric
insulin.
[0033] Another advantage is that the size of the particles
delivered will be relatively independent of the surrounding
humidity.
[0034] It is an object of this invention to demonstrate a novel
application for Humalog.TM. as a monomeric insulin analog well
suited for pulmonary drug delivery.
[0035] It is an object of this invention to demonstrate that
Humalog.TM. provides unique benefits when delivered via the lung by
reducing the degree to which lung sequestration occurs following
aerosolized delivery.
[0036] It is an object of this invention to demonstrate that
aerosolized delivery of Humalog.TM. in place of conventional
formulations of recombinant human insulin makes a repeatable blood
concentration versus time profile substantially less dependent of
the patients final inhaled volume at delivery.
[0037] It is an object of this invention to demonstrate that by
increasing the blood concentration versus time profile of the
delivered monomeric insulin such as Humalog.TM. (regardless of
breathing maneuver after delivery) that a more reproducible and
consistent effect on serum blood glucose can be achieved.
[0038] It is another object of this invention to demonstrate that
the increased reproducibility seen after the delivery of
Humalog.TM. via aerosolization into the lung results in a more
economical approach to the pulmonary drug delivery of insulin than
offered by the delivery of regular recombinant human insulin to the
lung via aerosolization.
[0039] These and other objects, advantages and features of the
present invention will become apparent to those persons skilled in
the art upon reading the details of the structure of the device,
formulation of compositions and methods of use, as more fully set
forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1 is a graph plotting the change in serum insulin
levels over time following different methods of insulin
administration;
[0041] FIG. 2 is a graph plotting the change in immunoreactive
insulin in blood serum over time following different methods of
insulin lispro administration.
[0042] FIG. 3 is a graph showing V.sub.L and V.sub.H in a preferred
breathing pattern at delivery.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0043] Before the present method of delivering aerosolized
monomeric insulin to treat diabetes mellitus and devices,
containers and formulations used in the treatment are described, it
is to be understood that this invention is not limited to the
particular methodology, containers, devices and formulations
described, as such methods, devices and formulations may, of
course, vary. It is also to be understood that the terminology used
herein is for the purpose of describing particular embodiments
only, and is not intended to limit the scope of the present
invention which will be limited only by the appended claims.
[0044] It must be noted that as used herein and in the appended
claims, the singular forms "a," "and;" and "the" include plural
referents unless the context clearly dictates otherwise. Thus, for
example, reference to "a formulation" includes mixtures of
different formulations, reference to "an analog" refers to one or
mixtures of insulin analogs, and reference to "the method of
treatment" includes reference to equivalent steps and methods known
to those skilled in the art, and so forth.
[0045] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods, devices and materials similar or equivalent to those
described herein can be used in the practice or testing of the
invention, the preferred methods, devices and materials are now
described. All publications mentioned herein are incorporated
herein by reference for the purpose of describing and disclosing
devices, formulations and methodologies which are described in the
publication and which might be used in connection with the
presently described invention.
[0046] Publications cited herein are cited for their disclosure
prior to the filing date of the present application. Nothing here
is to be construed as an admission that the inventors are not
entitled to antedate the publications by virtue of an earlier
priority date or prior date of invention. Further the actual
publication dates may be different from those shown and require
independent verification.
Definitions
[0047] The term "insulin" shall be interpreted to encompass fast
acting "regular" insulin, natural extracted human insulin,
recombinantly produced human insulin, insulin extracted from bovine
and/or porcine sources, recombinantly produced porcine and bovine
insulin and mixtures of any of these insulin products. The term is
intended to encompass the polypeptide normally used in the
treatment of diabetics in a substantially purified form but
encompasses the use of the term in its commercially available
pharmaceutical form which includes additional excipients. Regular
insulin is preferably recombinantly produced and may be dehydrated
(completely dried) or in solution. For purposes of the present
invention insulin is particularly characterized by molecules which
form complexes, particularly hexamers in solution and when in the
human body the hexamer complexes disassociate much more slowly than
monomeric insulin.
[0048] The "monomeric insulin" is intended to encompass any form of
an insulin molecule which is different from regular insulin wherein
the difference results in the insulin molecules not maintaining
hexamer complexes in a human which hexamers are characteristic of
insulin. Monomeric insulin exists predominantly in a monomer form
or quickly dissociates into a monomeric form in the human body. The
change which induces the monomeric form may be caused by one or
more of the amino acids within the polypeptide chain being replaced
with an alternative amino acid and/or wherein one or more of the
amino acids has been deleted or wherein one or more additional
amino acids has been added to the polypeptide chain or amino acid
sequences which act as insulin in decreasing blood glucose levels
and/or where bonds such as disulfide bonds are deleted, added or
moved in position relative to natural human insulin. The change may
also by obtained by using a different salt form e.g. replacing the
zinc cations with sodium cations. The preferred monomeric insulin
is insulin lispro in a zinc salt form as disclosed in U.S. Pat. No.
5,547,929, issued Aug. 20, 1996 and see also U.S. Pat. Nos.
5,514,646 and 5,700,662 all of which are incorporated herein by
reference. It should be noted that insulin as well as monomeric
insulin will disassociate into monomeric forms over time. However,
monomeric insulin will disassociate into the monomeric form, in a
human body, at twice the rate or faster than insulin when it is
administered subcutaneously. It should be noted that insulin lispro
disassociates into the monomeric form at approximately three times
the rate as compared to regular insulin when it is administered
subcutaneously.
[0049] The terms "V.sub.h" and "high volume" are used
interchangeably here and shall mean that after an aerosolized dose
is created the patient inhales the dose and continues to inhale a
high volume. More specifically, the patient inhales a high volume
which is approximately 80% or more of the patient's total lung
capacity. For an adult with a 5 liter lung volume the inhalation
would be approximately 4 liters or more i.e. up to the total lung
volume. Some error should be accounted for. Thus the high volume
can be 65% to 100% of the total lung volume depending on the lung
volume of the patient. Within the specific examples shown here the
high inhaled volume for healthy male patients with a total lung
volume of approximately 5 liters was in general about 4.7 liters.
High volume is preferably as close to 100% as the patient can
inhale.
[0050] The terms "V.sub.L" and "Low volume" refer to a smaller
inhaled volume as compared to an inhaled high volume of air with
the aerosolized delivery of insulin. Even without inhaling the lung
will retain some air. Thus, a low inhaled volume is approximately
40% plus or minus 15% of the patient's total lung volume. For the
experiments shown here a low inhaled volume involved inhaling
approximately 3 liters or less. It should be noted that inhaled
volumes are volumes recorded at Body Temperature and Pressure
Standard, i.e. the units are liters (btps). The terms V.sub.L
V.sub.H can be further understood in connection with FIGS. 3 and it
description.
[0051] The term "acceptable serum glucose level" is intended to
mean a glucose level above 50 mg/dl and below 300 mg/dl. more
preferably 80 mg/dl to 200 mg/dl and most preferably about 100
mg/dl. It will be understood by those skilled in the art that
levels of about 50 mg/dl are considered low and that levels of
about 300 mg/dl are considered high, although acceptable in the
sense that these levels are generally not fatal. It is an important
aspect of the invention to maintain more acceptable levels which
are above the low of 50 mg/dl and below the high of 300 mg/dl with
it being more acceptable to deliver doses of insulin so as to keep
the patient as close as possible to about 100 mg/dl.
[0052] The term "blood concentration versus time profile" shall be
interpreted to mean the concentration of a drug in the blood or
plasma over time. This can be characterized by means of a graph
showing the concentration of a drug (e.g. insulin or an insulin
analog or "immunoreactive insulin" as a surrogate measurement for
an insulin analog such as insulin lispro) on the Y axis and time on
the X axis. The blood concentration versus time profile can also be
characterized by certain pharmacokinetic parameters such as
C.sub.max (the maximum concentration of the drug seen over the
measured time interval) and T.sub.max (the time at which C.sub.max
was observed). Note that, by these criteria, two different blood
concentration versus time profiles may be associated with similar
or even identical bioavailability measurements. The blood
concentration versus time profile is crucial for drugs such as
insulin and insulin analogs where the time at which peak
concentration preferably occurs in conjunction with peak blood
glucose levels following a meal. Different values of T.sub.max for
two different insulin preparations or delivery methods could
therefore be associated with significant differences in safety and
efficacy.
[0053] The term "dosing event" shall be interpreted to mean the
administration of regular insulin and/or monomeric insulin to a
patient in need thereof by the intrapulmonary route of
administration which event may encompass one or more releases of
formulation from a dispensing device (from one or more containers)
over a period of time of 15 minutes or less, preferably 10 minutes
or less, and more preferably 5 minutes or less, during which period
one or more inhalations are made by the patient and one or more
doses of regular insulin or monomeric insulin are released and
inhaled. A dosing event shall involve the administration of regular
insulin or monomeric insulin to the patient in an amount of about 1
unit to about 30 units in a single dosing event which may involve
the release of from about 1 to about 300 units from the device.
[0054] The term "inspiratory flow rate" shall mean a value of air
flow rate measured, calculated and/or determined based on the speed
of the air passing a given point in a measuring device assuming
atmospheric pressure .+-.5% and a temperature in the range of about
10.degree. C., to 40.degree. C.
[0055] The term "inspiratory flow" shall be interpreted to mean a
value of air flow calculated based on the speed of the air passing
a given point along with the volume of the air that has passed that
point with the volume calculation being based on integration of the
flow rate data and assuming atmospheric pressure, .+-.5% and
temperature in the range of about 10.degree. C. to about
400.degree. C.
[0056] The term "inspiratory volume" shall mean a determined,
calculated and/or measured volume of air passing a given point into
the lungs of a patient assuming atmospheric pressure .+-.5 % and a
temperature in the range of 10.degree. C. to 40.degree. C.
[0057] The term "inhaling maximally" shall mean that the patient
makes a maximal effort to inhale air into the lungs.
[0058] The term "inspiratory flow profile" shall be interpreted to
mean data calculated in one or more events measuring inspiratory
flow and cumulative volume, which profile can be used to determine
a point within a patient's inspiratory cycle which is preferred for
the release of aerosol to be delivered to a patient. The point
within the inspiratory cycle where drug is released may be based on
a point within the inspiratory cycle likely to result in the
maximum delivery of drug and/or based on a point in the cycle most
likely to result in the delivery of a reproducible amount of drug
to the patient at each release of drug. Repeatability of the amount
delivered is the primary criterion and maximizing the amount
delivered is an important but secondary criterion. Thus, a large
number of different drug release points might be selected and
provide for repeatability in dosing provided the selected point is
again selected for subsequent releases. To insure maximum drug
delivery the point is selected within given parameters.
[0059] The term "therapeutic index" refers to the therapeutic index
of a drug defined as the ratio of toxic to therapeutic dose. Drugs
with a therapeutic index near unity achieve their therapeutic
effect at doses very close to the toxic level and as such have a
narrow therapeutic window, i.e. a narrow dose range over which they
may be administered.
[0060] The term "liquid formulation" is used herein to describe any
pharmaceutically active insulin, including insulin and/or monomeric
insulin for treating diabetes mellitus by itself or with a
pharmaceutically acceptable carrier in flowable liquid form and
preferably having a viscosity and other characteristics such that
the formulation is aerosolized into particles which are inhaled
into the lungs of a patient after the formulation is moved through
a porous membrane of the invention. Such formulations are
preferably solutions. e.g. aqueous solutions, ethanolic solutions,
aqueous/ethanolic solutions, saline solutions and colloidal
suspensions. Formulations can be solutions or suspensions of drug
in any fluid including fluids in the form of a low boiling point
propellant.
[0061] The term "formulation" is used to encompass the term "liquid
formulation" and to further include dry powders of insulin and/or
monomer insulin along with excipient materials. Preferred
formulations are aqueous solutions of monomeric insulin but include
dry powders and dispersions.
[0062] The term "substantially" dry shall mean particles of an
aerosol which contain less than 10% free water, ethanol or other
liquid carrier based on total weight and preferably contains no
detectable free liquid carrier.
[0063] The term "bulk flow rate" shall mean the average velocity at
which air moves through a channel considering that the flow rate is
at a maximum in the center of the channel and at a minimum at the
inner surface of the channel.
[0064] The term "flow boundary layer" shall mean a set of points
defining a layer above the inner surface of a channel through which
air flows wherein the air flow rate below the boundary layer is
substantially below the bulk flow rate, e.g., 50% or less than the
bulk flow rate.
[0065] The term "carrier" shall mean a non-active portion of a
formulation. In aqueous formulations, it is a liquid, flowable,
pharmaceutically acceptable excipient material which insulin and/or
monomeric insulin is suspended in or more preferably dissolved in.
In a dry powder, it shall include non-active components, e.g., to
keep the particles separate. Useful carriers do not adversely
interact with the monomeric insulin and have properties which allow
for the formation of aerosolized particles--preferably particles
having a diameter in the range of 0.5 to 3.0 microns when a
formulation comprising the carrier and insulin analog is forced
through pores having a diameter of 0.25 to 3.0 microns. Preferred
carriers for liquid solutions include water, ethanol and mixtures
thereof. Other carriers can be used provided that they can be
formulated to create a suitable aerosol and do not adversely effect
insulin, monomeric insulin or human lung tissue.
[0066] The term "measuring" describes an event whereby either the
inspiratory flow rate or inspiratory volume of the patient is
measured (via electronic sensors or by mechanical means) in order
to determine an optimal point in the inspiratory cycle at which to
release aerosolized drug. An actual measurement of both rate and
volume may be made or the rate can be directly measured and the
volume calculated based on the measured rate. It is also preferable
to continue measuring inspiratory flow during and after any drug
delivery and to record inspiratory flow rate and volume before,
during and after the release of drug. Such reading makes it
possible to determine if drug was properly delivered to the
patient.
[0067] Each of the parameters discussed above is measured during
quantitative spirometry. A patient's individual performance can be
compared against his personal best data, individual indices can be
compared with each other for an individual patient (e.g. FEV.sub.1
divided by FVC, producing a dimensionless index useful in assessing
the severity of acute asthma symptoms), or each of these indices
can be compared against an expected value. Expected values for
indices derived from quantitative spirometry are calculated as a
function of the patient's sex, height, weight and age.
General Methodology
[0068] The invention comprises aerosolizing a formulation of
monomeric insulin (e.g. insulin lispro) and inhaling the
aerosolized formulation into the lungs. Although the inhalation of
insulin which results in the insulin entering the circulatory
system is known, correctly dosing the amount of insulin delivered
by inhalation has been problematic--however, see U.S. Pat. No. 5,
672,581 issued Sep. 30, 1997. The devices, formulations and methods
disclosed herein are useful in solving problems with prior methods.
For example, when regular insulin is delivered to a patient by
inhalation the amount of effect on glucose levels varies
considerably based on the lung volume inhaled by the patient with
the aerosolized insulin at delivery. If the blood glucose level is
not quickly lowered the patient may administer additional insulin
which in combination with that already administered will
dangerously lower the blood glucose level. The present invention
endeavors to provide a preferred blood concentration versus time
profile by the delivery of monomeric insulin which rapidly
disassociates into its monomeric form in a human and as such moves
into the circulatory system more rapidly as compared to regular
insulin. When regular insulin is delivered by inhalation, the
effect on lowering glucose levels is often different depending on
the total inhaled volume of by the patient at delivery. Results
provided here show that the delivery of monomeric insulin is much
less effected by the patient's total inhaled volume at delivering
as compared to the aerosolized delivery of regular insulin thereby
improving repeatability of dosing. Thus, the data shown here
provide improved unexpected results with respect to a practical
method of treating Diabetes Mellitus by aerosolized drug
delivery.
[0069] FIGS. 1 and 2 along with tables 1 and 2 dramatically show
how the total inhaled volume at delivery has a dramatically greater
effect on the blood concentration versus time profile following
aerosolized delivery of insulin as compared to aerosolized delivery
of monomeric insulin. In tables 1 and 2 as well as within FIGS. 1
and 2 a reference is made to "V.sub.L" and "V.sub.H" which refers
to low volume and high volume inhalations at delivery respectively.
A more complete understanding of what is meant by these terms and
how the invention is carried out can be understood by reference to
FIG. 3.
[0070] FIG. 3 is a graph of inspiratory volume verses inspiratory
flow rate in liters per second. Regardless of whether one is
delivering insulin or monomeric insulin it is preferable to begin
the release of the aerosolized dose to the patient when the inhaled
inspiratory volume and inspiratory flow rate are within the
parameters of the rectangle 1 shown in FIG. 3. In the specific
example of FIG. 3 the release occurs at the point 2. The parameters
of the rectangle shown indicate that release should occur at an
inspiratory volume above 0.1 liter and prior to 0.8 liter. Further,
the aerosol is released after the patients inhalation rate exceeds
0.1 liters per second but prior to the rate exceeding the 2.0
liters per second. In the examples shown the release occurs at an
inspiratory volume of about 0.5 liters and at an inspiratory rate
of about 1.0 liters per second. To enhance repeatability of dosing
the patient would deliver each dose of insulin thereafter at the
same inspiratory volume and inspiratory flow rate. More
specifically the device of the invention will automatically release
the aerosolized dose after it records an inspiratory volume of
about 0.5 liters and an inspiratory flow rate of about 1 liter per
second. Thereafter, the patient is coached to continue inhalation
at the same rate e.g. at a rate of about 1 liter per second. For a
low volume maneuver the inhalation is continued until the patient
has inhaled 2 liters of air as shown by the point 3 in FIG. 3. For
a high volume maneuver the patient continues inhaling until the
patient has inhaled 4 liters of air or more as shown by point 4 in
FIG. 3.
[0071] A comparison of FIGS. 1 and 2 as well as tables 1 and 2
shows that inhaling to a low or high volume at delivery does not
effect the results significantly results when delivering monomeric
insulin--but substantially effects results when delivering
insulin.
[0072] The preferred monomeric insulin is insulin lispro as
described in the 1997 PDR at page 1488 (incorporated herein by
reference). This preferred monomeric insulin is also referred to
herein by the commercial name "Humalog.TM.." The following provides
a description of the conceptual basis of the present invention.
[0073] Insulin has been used for over 50 years for the management
of diabetes mellitus. Insulin is a naturally occurring hormone
which plays a clinical role in glucose metabolism and its absence
in patients with Type I Diabetes is a fatal illness unless
exogenous insulin is used as part of an insulin replacement therapy
program.
[0074] Patients have self administered insulin subcutaneously (SC)
for decades as a means for managing their diabetes. The total daily
dose of insulin required by individual patients varies. The
availability of portable blood glucose monitors over the last
decade has been a significant advancement in that patients can now
measure their own blood glucose levels in self dose insulin by
injection according to their needs. Many things affect the daily
requirement for insulin. These multiple factors require that
patients measure blood glucose levels to achieve tight control of
their blood glucose.
[0075] The Diabetes Complications and Control Trial (DCCT), a
multicenter study designed to evaluate the potential long term
beneficial effects of tight blood glucose control, was recently
completed. This study demonstrated that insulin requiring diabetics
who maintained their serum glucose within a specific range over
time had a significantly reduced complication rate, including the
avoidance of the consequences of peripheral vascular disease (e.g.
renal failure, chronic diabetic retinopathy and lower extremity
problems).
[0076] A key element in the attainment of a stable blood glucose
level over time involves the administration of subcutaneously
administered insulin prior to meal time. In this way, blood levels
of insulin will appear coincident with the increase in blood
glucose associated with meal digestion. Recombinant human insulin,
which has been available for over more than 10 years, is available
in a short acting form (regular insulin) which is appropriate for
self administration by injection prior to meal time. Unfortunately,
recombinant human insulin must be dosed by injection approximately
one half hour prior to meal time in order to insure that a rise in
blood glucose does not occur unopposed by exogenous insulin
levels.
[0077] The requirement that recombinant human insulin be injected
one half hour prior to meal time is burdensome because it requires
that patients precisely anticipate the times they will be eating.
Eli Lilly has recently introduced insulin lispro which is sold as
Humalog.TM. (a recombinant human insulin analog), which is more
rapidly absorbed than recombinant human insulin when injected
subcutaneously. Because it works more quickly than recombinant
human insulin, Humalog.TM. can be given just prior to meal time
thereby reducing the burden on the patient to plan ahead prior to
eating.
[0078] Recombinant human insulin in aqueous solution is in a
hexameric configuration. In other words, six molecules of
recombinant insulin are noncovalently associated in a hexameric
complex when dissolved in water in the presence of zinc ions.
Studies have demonstrated that hexameric insulin is not rapidly
absorbed from the subcutaneous space. In order for recombinant
human insulin to be absorbed into circulation, the hexameric form
must first dissociate into dimer and/or a monomeric forms i.e.,
these forms are required before the material can transit into the
blood stream. This requirement for recombinant human insulin to
disassociate from hexameric to dimer or monomeric form prior to
absorption is believed to be responsible for the 30 minutes
required for a self administered dose of subcutaneous recombinant
human insulin to produce a measurable therapeutic blood level.
[0079] Although Humalog.TM. exists in solution outside the body as
a hexamer, it very rapidly disassociates into a monomeric form
following subcutaneous administration. Clinical studies have
demonstrated that Humalog.TM. is absorbed quantitatively faster
than recombinant human insulin after subcutaneous
administration.
[0080] To control glucose levels insulin is dosed in units. Because
insulin is generally in the form of regular insulin and is
generally administered subcutaneously the units of measurements
used here are subcutaneous equivalents of regular insulin.
[0081] Because insulin must be administered frequently in order to
allow patients to attain a tight degree of control over their serum
glucose, the fact that all insulin products currently need to be
delivered by injection is a hindrance to compliance. Results from a
DCCT study demonstrate that insulin should ideally be administered
4-6 times each day in order for patients to be likely to achieve an
adequate level of blood glucose control to obtain a reduction in
complication rate associated with diabetes. A noninvasive method
for the delivery of insulin could be beneficial in increasing
patient compliance with frequent self administration of insulin
throughout the day.
[0082] The noninvasive delivery of proteins and peptides has been
an elusive goal of the drug delivery industry. Because proteins are
rapidly disassociated in the GI tract, oral forms for the delivery
of proteins as tablets or capsules have thus far seen limited
success. Inhalational drug delivery has been demonstrated to be a
viable option for the delivery of proteins and peptides such as
insulin via the lung, see U.S. Pat. No. 5,364,838, issued Nov. 15,
1994 and U.S. Pat. No. 5,672,581 issued Sep. 30, 1997.
[0083] Recent studies have demonstrated that insulin can be
reproducibly administered for inhalation to healthy volunteers
producing a rapid rise in measurable serum glucose level as well as
a rapid fall in blood glucose. U.S. Pat. No. 5,544,646 describes
systems for the intrapulmonary delivery of aerosolized aqueous
formulations. The system described allows unit dosed packages of
aqueous formulated drug to be delivered deep into the lung for
systemic effect. U.S. Pat. No. 5,558,085, Intrapulmonary Delivery
of Peptide Drugs illustrates how proteins and peptides can be
delivered as fine particle aerosols through the lung for systemic
effect. U.S. Pat. No. 5,497,763 describes a disposable package for
intrapulmonary delivery of aerosolized formulations which allows
sealed packets of preformulated drugs such as insulin to be
inserted by the patient into aerosolization apparatus for producing
fine particle aerosols for deep inhalation.
[0084] By quantitatively measuring the inspiratory flow rate and
volume during the patients inspiratory maneuver while breathing
through the aerosolization system, an optimum point for the
delivery of a bolus of aerosolized medication can be determined.
U.S. Pat. No. 5,509,404 describes intrapulmonary drug delivery
within therapeutically relevant inspiratory flow volume values and
illustrates how specific inspiratory flow rate and flow volume
criteria can be used to enhance the reproducibility of drugs
delivered via the lung for systemic effect. U.S. Pat. No.
5,522,385, Dynamic Particle Size Control for Aerosolized Drug
Delivery demonstrates that the parameters of the emitted aerosol
can be varied to optimize the delivery of an inhaled aerosol for
systemic effect.
[0085] U.S. patent application Ser. No. 08/754,423, filed Nov. 11,
1996, illustrates that recombinant human insulin, when delivered as
an aerosol for deep inhalation into the lung for systemic effect,
is sequestered in the lung to a significant degree. This U.S.
patent application describes how insulin sequestered within the
lung can be made to transit into the systemic circulation if the
patient engages in certain specific inspiratory maneuvers following
delivery.
[0086] Although the reasons for sequestration of insulin in the
lung following aerosolized delivery are not known, we speculate
that, as with subcutaneous delivery, the dissociation of insulin
from hexameric to monomeric form is an important first step prior
to the absorption of insulin into the blood stream. Recent
controlled experiments conducted by the inventors quantified the
degree to which insulin is sequestered into the lung following
aerosolized delivery. In these controlled experiments, the amount
of insulin or monomeric insulin released into the blood stream
following aerosol delivery was quantified in cross over fashion
with and then without a forced expiratory maneuver following
delivery. Results shown here indicated that the blood concentration
versus time profile of monomeric insulin is not substantially
affected compared to insulin by a patient's respiratory maneuver at
delivery.
[0087] Although multiple studies have evaluated the feasibility of
the delivery of recombinant human insulin via the lung as a fine
particle aerosol, no studies have appeared demonstrating that
recombinant human insulin is sequestered in the lung following
aerosolized delivery. Recently conducted clinical studies
demonstrate that significant sequestration of recombinant human
insulin is occurring in the lung following aerosol drug delivery.
Although this degree of sequestration can be reversed by certain
specific pulmonary maneuvers as shown in our copending application,
it will be desirable to substantially reduce or eliminate this
sequestration altogether.
[0088] Because Humalog.TM. rapidly disassociates into monomeric
insulin, it is uniquely suited for delivery via the lung.
[0089] The invention includes containers, devices and methods which
provide a non-invasive means of treating diabetes mellitus in a
manner which makes it possible to accurately dose the
administration of aerosolized monomeric insulin and thereby
maintain tight control over serum glucose levels of a patient
suffering from the disease. The device of the invention provides a
number of features which make it possible to achieve the controlled
and repeatable dosing procedure required for treating diabetes.
[0090] Specifically, the device is not directly actuated by the
patient in the sense that no button is pushed nor valve released by
the patient applying physical pressure. On the contrary, the device
of the invention provides that aerosolized insulin formulation is
released automatically upon receipt of a signal from a
microprocessor programmed to send a signal when data is received
from a monitoring device such as an airflow rate monitoring
device.
[0091] A patient using the device withdraws air from a mouthpiece
and the inspiratory rate of the patient is measured as is
cumulative inspiratory volume. The monitoring device continually
sends information to the microprocessor, and when the
microprocessor determines that the optimal point in the respiratory
cycle is reached, the microprocessor actuates the opening of the
valve allowing release of insulin. Accordingly, drug is always
delivered at a preprogrammed place in the respiratory flow profile
of the particular patient which is selected specifically to
maximize reproducibility of drug delivery to the peripheral lung
regions. It is pointed out that the device of the present invention
can be used to, and actually does, improve the efficiency of drug
delivery. However, this is not a critical feature. Important
features are the enhanced repeatability of blood concentration
versus time profile and the increased rate at which insulin is
brought into the circulatory system. The invention makes it
possible to deliver a tightly controlled amount of drug at a
particular point in the inspiratory cycle so as to assure the
delivery of a controlled and repeatable amount of drug to the lungs
of each individual patient.
[0092] The automatic control of monomeric insulin release provides
a repeatable means controlling the glucose level of a patient.
Because aerosolized monomeric insulin formulation is released
automatically and not manually, it can predictably and repeatedly
be released in the same amount each time to provide a preprogrammed
measured amount which is desired.
[0093] When it is desirable to decrease particle size by heating, a
heating element is used. The amount of heat added to the air is
about 20 Joules or more, preferably 20 Joules to about 100 Joules
and more preferably 20 Joules to about 50 Joules per 10 .mu.l of
formulation.
[0094] There is considerable variability with respect to the amount
of insulin which is delivered to a patient when the insulin is
being administered by injection. Patients requiring the
administration of injectable insulin use commercial insulin which
is prepared in concentrations of 100 units per milliliter, although
higher concentrations up to about 1,000 units per milliliter can be
obtained. It is preferable to use more highly concentrated
monomeric insulin in connection with the present invention. If
insulin containing 500 units of insulin per milliliter is used and
a patient is administering 25 units, then the patient will only
need to administer 0.05 milliliters of the concentrated insulin to
the lungs of the patient to achieve the desired dose.
[0095] The symptoms of diabetes can be readily controlled with the
administration of insulin. However, it is extremely difficult, to
normalize the blood sugar throughout a 24-hour period utilizing
traditional insulin therapy given as one or two injections per day.
It is possible to more closely approach normalized blood sugar
levels with the present invention. Improvements are obtained by
smaller, more frequent dosing and by timing dosing relative to
meals, exercise and sleep
[0096] The precise amount of insulin administered to a patient
varies considerably depending upon the degree of the disease and
the size of the patient. A normal-weight adult may be started on
about a 15-20 units a day (as explained above the units are
equivalent subcutaneous units) in that the estimated daily insulin
production rate in non-diabetic subjects of normal size is
approximately 25 units per day. It is preferable to administer
approximately the same quantity of insulin for several days before
changing the dosing regime except with hypoglycemic patients for
which the dose should be immediately decreased unless a clearly
evident nonrecurrent cause of hypoglycemia (such as not eating,
i.e., missing a typical meal) is present. In general, the changes
should not be more than five to ten units per day. It is typical to
administer about two-thirds of the total insulin daily dosage
before breakfast and administer the remainder before supper. When
the total dosage reaches 50 or 60 units per day, a plurality of
smaller doses are often required since peak action of insulin
appears to be dose related, i.e., a low dose may exhibit maximal
activity earlier and disappear sooner than a large dose. All
patients are generally instructed to reduce insulin dosage by about
5 to 10 units per day when extra activity is anticipated. In a
similar manner, a small amount of extra insulin may be taken before
a meal that contains extra calories or food which is not generally
eaten by the diabetic patient. The inhalation device of the present
invention is particularly useful with respect to providing such
small amounts of additional insulin.
[0097] Several types of insulin formulations are commercially
available. When larger doses of insulin must be administered at a
single point in time, it may be preferable to administer
intermediate or long-acting insulin formulations. Such formulations
release some insulin immediately and provide a more sustained
release of the remainder of the insulin over time. Such
formulations are described further below in the "Insulin Containing
Formulations" section.
[0098] There is a differential between the amount of insulin and/or
monomeric insulin actually released from the device and the amount
actually delivered to the patient. The present device is two to ten
times more efficient than conventional inhalation devices (i.e.,
MDIs or metered dose inhalers) which have an efficiency as low as
10% meaning that as little as 10% of the aerosolized insulin may
actually reach the lungs of the patient. The efficiency of the
delivery will vary somewhat from patient to patient and should be
taken into account when programming the device for the release of
insulin.
[0099] One of the difficulties with aerosolized delivery of insulin
is that the patient and/or the caregiver cannot determine precisely
how much insulin has entered the circulatory system. Accordingly,
if the patient has been dosed with what is believed to be an
adequate amount of aerosolized insulin and the glucose level
remains high one might assume that the aerosolized dose was not
properly delivered. For example, the insulin might have been
improperly delivered against the patient's mouth surfaces or throat
where it will not be absorbed into the circulatory system. However,
it may be that the insulin is properly delivered to the lung (e.g.,
provided on the outer peripheral areas of the lung) but has not yet
migrated into the circulatory system.
[0100] Obese patients are generally somewhat less sensitive to
insulin and must be provided with higher doses of insulin in order
to achieve the same effect as normal weight patients. Dosing
characteristics based on insulin sensitivity are known to those
skilled in the art and are taken into consideration with respect to
the administration of injectable insulin. The present invention
makes it possible to vary dosing over time if insulin sensitivity
chances and/or if user compliance and/or lung efficiency changes
over time.
[0101] Based on the above, it will be understood that the dosing or
amount of monomeric insulin actually released from the device can
be changed based on the most immediately prior monitoring event
wherein the inspiratory flow of a patient's inhalation is measured.
The amount of insulin released can also be varied based on factors
such as timing and timing is, in general, connected to meal times,
sleep times and, to a certain extent, exercise times. Although all
or any of these events can be used to change the amount of insulin
released from the device and thus the amount of insulin delivered
to the patient, ultimately, the amount released and delivered to
the patient is based on the patient's serum glucose levels. It is
important to maintain the serum glucose levels of the patient
within acceptable levels (greater than 60 mg/dl and less than 125
mg/100 ml, and most preferably to maintain those levels at about 80
mg/100 ml.
[0102] Variations in doses are calculated by monitoring serum
glucose levels in response to known amounts of insulin released
from the device If the response in decreasing serum glucose level
is higher than with previous readings, then the dosage is
decreased. If the response in decreasing serum glucose level is
lower than with previous readings, then the dosing amount is
increased. The increases and decreases are gradual and are
preferably based on averages (of 10 or more readings of glucose
levels after 10 or more dosing events) and not a single dosing
event and monitoring event with respect to serum glucose levels.
The present invention can record dosing events and serum glucose
levels over time, calculate averages and deduce preferred changes
in administration of insulin.
[0103] As another feature of the invention, the device can be
programmed so as to prevent the administration of more than a given
amount of insulin within a given period of time. For example, if
the patient normally requires 25 units per day of insulin, the
microprocessor of the inhalation device can be programmed to
prevent further release of the valve after 35 units has been
administered within a given day. Setting a slightly higher limit
would allow for the patient to administer additional insulin, if
needed, due to larger than normal meals and/or account for
misdelivery of insulin such as due to coughing or sneezing during
an attempted delivery.
[0104] The ability to prevent overdosing is a characteristic of the
device due to the ability of the device to monitor the amount of
insulin released and calculate the approximate amount of insulin
delivered to the patient based on monitoring given events such as
airflow rate and serum glucose levels. The ability of the present
device to prevent overdosing is not merely a monitoring system
which prevents further manual actuation of a button. As indicated
above, the device used in connection with the present invention is
not manually actuated, but is fired in response to an electrical
signal received from a microprocessor. Applicant's device does not
allow for the release of insulin merely by the manual actuation of
a button to fire a burst of insulin into the air.
[0105] The microprocessor of applicant's invention can be designed
so as to allow for an override feature which would allow for the
administration of additional insulin. The override feature could be
actuated in an emergency situation. Alternatively, the override
feature could be actuated when the device is electronically
connected with a serum glucose level monitoring device which
determines that serum glucose levels increase to dangerously high
levels.
[0106] The microprocessor of applicant's invention will preferably
include a timing device. The timing device can be electrically
connected with visual display signals as well as audio alarm
signals. Using the timing device, the microprocessor can be
programmed so as to allow for a visual or audio signal to be sent
when the patient would be normally expected to administer insulin.
In addition to indicating the time of administration (preferably by
audio signal), the device can indicate the amount of insulin which
should be administered by providing a visual display. For example,
the audio alarm could sound alerting the patient that insulin
should be administered. At the same time, the visual display could
indicate "five units" as the amount of insulin to be administered.
At this point, a monitoring event could take place. After the
predetermined dose of five units had been administered, the visual
display would indicate that the dosing event had ended. If the
patient did not complete the dosing event by administering the
stated amount of insulin, the patient would be reminded of such by
the initiation of another audio signal, followed by a visual
display instructing the patient to continue administration.
[0107] Additional information regarding dosing with insulin via
injection can be found within Harrison's--Principles of Internal
Medicine (most recent edition) published by McGraw Hill Book
Company, New York, incorporated herein by reference to disclose
conventional information regarding dosing insulin via
injection.
Treatment Via Monomeric Insulin
[0108] The methodologies of the present invention are preferably
carried out using recombinantly produced monomeric insulin in a
liquid formulation. A preferred insulin is insulin lispro, sold by
Lilly under the name Humalog.TM.. This analog is absorbed faster
after subcutaneous injection. Another type of insulin analog is
referred to as superactive insulin. In general, superactive insulin
has increased activity over natural human insulin. Accordingly,
such insulin can be administered in substantially smaller amounts
while obtaining substantially the same effect with respect to
reducing serum glucose levels. Another general type of analog is
referred to as hepatospecific insulin. Hepatospecific insulin
analogs are more active in the liver than in adipose tissue and
offer several advantages over currently available insulin therapy.
Hepatospecific analogs provide preferential hepatic uptake during
peripheral subcutaneous administration, thereby mimicking, more
closely, the metabolic balance between the liver and the peripheral
tissues. Obtaining the correct metabolic balance is an important
part of proper treatment of diabetics and administration via the
intrapulmonary route should provide advantages over intermuscular
injection with respect to obtaining such a balance. It may be
desirable to include mixtures of conventional insulin with insulin
lispro or with insulin which is hepatospecific and/or with
superactive insulin analogs. Hepatospecific analogs are disclosed
and described within published PET application WO90/12814,
published Nov. 1, 1990, which application is incorporated herein by
reference for its disclosure of such hepatospecific insulin analogs
and in order to disclose other information cited within the other
publications referred to within WO90/12814. To carry out the
invention these insulins must be in a monomeric form or take a
monomeric form quickly in a human.
[0109] U.S. patent application Ser. No. 074,558 discloses a
superactive human insulin analog, [10-Aspartic Acid-B] human
insulin, which has increased activity over natural human insulin.
Specifically, [10-Aspartic Acid-B] human insulin was determined to
be 4 to 5 times more potent than natural insulins. U.S. patent
application Ser. No. 273,957 and International Application Serial
No. PCT/US88/02289 disclose other superactive insulin analogs,
des-pentapeptide (B26-B30)-[Asp.sup.B10,
Tyr.sup.B25-.alpha.-carboxamide] human insulin,
(B26-B30)-[Glu.sup.B10, Tyr.sup.B25-.alpha.-carboxamide] human
insulin, and further insulin analogs of the formula
des(B26-B30)-[X.sup.B10, Tyr.sup.B25-.alpha.-carbo- xamide] human
insulin, in which X is a residue substituted at position 10 of the
B chain. These insulin analogs have potencies anywhere from 11 to
20 times that of natural human insulin. All of the above-described
insulin analogs involve amino acid substitutions along the A or B
chains of natural human insulin, which increase the potency of the
compound or change other properties of the compound.
[0110] Other than insulin lispro the insulin analogs are not
presently used for the treatment of patients on a commercial scale.
However, insulin lispro and other insulin analogs being developed
could be used with the present invention in that the present
invention can be used to provide variable dosing in response to
currently measured serum glucose levels. Further, since many
insulin analogs are more potent than conventional insulin, their
delivery via the intrapulmonary route is particularly
convenient.
[0111] Information regarding dosing insulin can be found within
Harrison's --Principles of Internal Medicine (most recent edition)
and the Drug Evaluation Manual, 1993 (AMA-Division of Drugs and
Toxicology), both of which are published by McGraw Hill Book
Company, New York, incorporated herein by reference to disclose
conventional information regarding dosing of insulin.
Monitoring Diabetic Control
[0112] All methods of treating diabetes involve measuring glucose
levels in some manner. Such measurements are necessary in order to
titrate proper dosing and avoid the over-administration of insulin
which can result in fatal hypoglycemia. Measurements of urine
glucose alone are insufficient to assess diabetic control and bring
mean plasma glucose values into a near normal range since the urine
will be free of glucose when the plasma concentration is relatively
normal. For this reason, "home glucose monitoring" is used in those
patients treated by continuous subcutaneous insulin infusion (CSII)
or multiple subcutaneous injection (MSI) techniques. Such
monitoring requires capillary blood which can be obtained in a
substantially painless manner using a small spring-triggered device
referred to as Autolet.TM. produced by Ulstr Scientific
Incorporated which device is equipped with small disposable
lancelets. The amount of glucose is analyzed using chemically
impregnated strips which are read in a commercially available
reflectance meter. One commercially available strip is referred to
as Chemstrip bG (produced by Bio-Dynamics). The Chemstrip Bg can
provide satisfactory values by visual inspection utilizing a
dual-color scale, thus eliminating the need for a reflectance
meter. Frequent measurement of the plasma glucose (a fairly
standard program utilizes seven or eight assays over a 24-hour
period) allows a reasonable assessment of mean plasma glucose
levels during the day and guides adjustment of insulin dosage.
[0113] The methodology of the present invention is preferably
utilized in combination with a closely controlled means of
monitoring serum glucose levels. More specifically, the invention
is used to administer doses of monomeric insulin via the
intrapulmonary route. The doses may be administered more frequently
but in somewhat smaller amounts than are generally administered by
injection. The amount of insulin and monomeric insulin administered
can be readily adjusted in that smaller amounts are generally
administered using the intrapulmonary delivery methodology of the
present invention.
[0114] During the day, as insulin is administered, serum glucose
levels are frequently monitored. The amount of insulin administered
can be dosed based on the monitored serum glucose levels, i.e., as
glucose levels increase, the amount of insulin can be increased,
and as glucose levels are seen to decrease, the dosing of insulin
can be decreased.
[0115] Based on the information disclosed herein in combination
with what is known about insulin dosing and serum glucose levels,
computer readable programs can be readily developed which can be
used in connection with the insulin delivery device of the present
invention. More specifically, a microprocessor of the type
disclosed in U.S. Pat. No. 5,542,410 can be programmed so as to
deliver precise doses of insulin which correspond to the particular
needs of the patient based on serum glucose monitoring information
which is supplied to the microprocessor. Further, the dosing
information contained within the microprocessor can be fed to a
separate computer and/or serum glucose monitoring device
(preferably portable) in order to calculate the best treatment and
dosing schedule for the particular patient.
Insulin Containing Formulations
[0116] A variety of different monomeric insulin containing
formulations can be used in connection with the present invention.
The active ingredient within such formulations is monomeric insulin
which can be combined with regular insulin. Further, the monomeric
insulin may be combined with an insulin analog which is an analog
of human insulin which has been recombinantly produced. Although
the monomeric insulin is generally present by itself as the sole
active ingredient, it may be present with an additional active
ingredient such as a sulfonylurea. However, such sulfonylureas are
generally administered separately in order to more closely control
dosing and serum glucose levels.
[0117] The present invention provides a great deal of flexibility
with respect to the types of monomeric insulin formulations to be
administered. For example, a container can include monomeric
insulin by itself or in combination with an analog of any type or
combinations of different insulin analogs. Further, a package can
be created wherein individual containers include different
formulations wherein the formulations are designed to achieve a
particular effect e.g., fast acting insulin or quick absorbing
insulin. The patient along with the care giver and careful
monitoring can determine the preferred insulin dosing protocol to
be followed for the particular patient.
[0118] The monomeric insulin may be provided as a dry powder by
itself, and in accordance with another formulation, the insulin or
active ingredient is provided in a solution formulation. The dry
powder could be directly inhaled by allowing inhalation only at the
same measured inspiratory flow rate and inspiratory volume for each
delivery. However, the powder is preferably dissolved in an aqueous
solvent to create a solution which is moved through a porous
membrane to create an aerosol for inhalation.
[0119] Any formulation which makes it possible to produce
aerosolized forms of monomeric insulin which can be inhaled and
delivered to a patient via the intrapulmonary route can be used in
connection with the present invention. Specific information
regarding formulations (which can be used in connection with
aerosolized delivery devices) are described within Remington's
Pharmaceutical Sciences, A. R. Gennaro editor (latest edition) Mack
Publishing Company. Regarding insulin formulations, it is also
useful to note Sciarra et al. [Journal of Pharmaceutical Sciences,
Vol. 65, No. 4, 1976].
[0120] The monomeric insulin is preferably included in a solution
such as the type of solution which is made commercially available
for injection and/or other solutions which are more acceptable for
intrapulmonary delivery. When preparing preferred formulations of
the invention which provide for the monomeric insulin, excipient
and solvent, any pharmaceutically acceptable excipient may be used
provided it is not toxic in the respiratory tract. The monomeric
insulin formulation preferably has a pH of about 7.4.+-.1.0.
[0121] Formulations include monomeric insulin dry powder by itself
and/or with an excipient. When such a formulation is used, it may
be used in combination with a gas propellant which gas propellant
is released over a predetermined amount of dried powder which is
forced into the air and inhaled by the patient. It is also possible
to design the device so that a predetermined amount of dry powder
is placed behind a gate. The gate is opened in the same manner as
the valve is released so that the same inspiratory flow rate and
inspiratory volume is repeatedly obtained. Thereafter, the dry
powder is inhaled by the patient and the insulin is delivered.
[0122] Rapidly acting preparations are always indicated in diabetic
emergencies and in CSII and MSI programs. Intermediate preparations
are used in conventional and MSI regimens. It is not possible to
delineate precisely the biologic responses to the various
preparations because peak effects and duration vary from patient to
patient and depend not only on route of administration but on dose.
The various insulins are available as rapid (regular, semilente),
intermediate (NPH, lente, globin), and long-acing (PZI, ultralente)
preparations, although not all manufacturers offer all varieties.
Lente and NPH insulin are used in most conventional therapy and are
roughly equivalent in biologic effects. These can be used with
monomeric insulin.
[0123] The methodology of the invention may be carried out using a
portable, hand-held, battery-powered device which uses a
microprocessor component as disclosed in U.S. Pat. Nos. 5,404,871,
issued Apr. 11, 1995 and U.S. Pat. No. 5,450,336, issued Sep. 12,
1995 both of which are incorporated herein by reference. In
accordance with another system the methodology of the invention
could be carried out using the device dosage units and system
disclosed in U.S. 94/05825 with modifications as described herein.
Monomeric insulin is included in an aqueous formulation which is
aerosolized by moving the formulation through a flexible porous
membrane. Alternatively, the methodology of the invention could be
carried out using a mechanical (non-electronic) device. Those
skilled in the art recognized that various components can be
mechanical set to actuate at a given inspiratory flow rate (e.g. a
spring biased valve) and at a given volume (e.g. a spinable
flywheel which rotates a given amount per a given volume). The
components of such devices could be set to allow drug release
inside defined parameters.
[0124] The monomeric insulin which is released to the patient may
be in a variety of different forms. For example, the insulin may be
an aqueous solution of drug, i.e., drug dissolved in water and
formed into small particles to create an aerosol which is delivered
to the patient. Alternatively, the drug may be in a solution or a
suspension wherein a low-boiling point propellant is used as a
carrier fluid. In yet, another embodiment the insulin may be in the
form of a dry powder which is intermixed with an airflow in order
to provide for delivery of drug to the patient. Regardless of the
type of drug or the form of the drug formulation, it is preferable
to create drug particles having a size in the range of about 0.5 to
12 microns, more preferably 14 microns. By creating drug particles
which have a relatively narrow range of size, it is possible to
further increase the efficiency of the drug delivery system and
improve the repeatability of the dosing. Thus, it is preferable
that the particles not only have a size in the range of 0.5 to 12
microns but that the mean particle size be within a narrow range so
that 80% or more of the particles being delivered to a patient have
a particle diameter which is within .+-.20% of the average particle
size, preferably .+-.10% and more preferably .+-.15% of the average
particle size.
[0125] An aerosol may be created by forcing drug through pores of a
membrane which pores have a size in the range of about 0.25 to 6
microns preferably 0.5 to 3.0 microns. When the pores have this
size the particles in the aerosol will have a diameter about twice
the diameter of the pore opening from which the formulation exits.
However, the particle size can be substantially reduced by adding
heat to the air around the particles and cause evaporation of
carrier. Drug particles may be released with an air flow intended
to keep the particles within this size range. The creation of small
particles may be facilitated by the use of the vibration device
which provides a vibration frequency in the range of about 800 to
about 4000 kilohertz. Those skilled in the art will recognize that
some adjustments can be made in the parameters such as the size of
the pores from which drug is released, vibration frequency and
amplitude, pressure, and other parameters based on the
concentration, density, viscosity and surface tension of the
formulation keeping in mind that the object is to provide
aerosolized particles having a diameter in the range of about 0.25
to 12 microns, preferably 1.0-3.0 microns.
[0126] The drug formulation may be a low viscosity liquid
formulation. The viscosity of the drug by itself or in combination
with a carrier is not of particular importance except to note that
the formulation preferably has characteristics such that it can be
forced out of openings of the flexible or convex membrane to form
an aerosol, e.g., using 20 to 400 psi to form an aerosol preferably
having a particle size in the range of about 0.5 to 6.0
microns.
[0127] Drug may be stored in and/or released from a container of
any desired size. In most cases the size of the container is not
directly related to the amount of drug being delivered in that most
formulations include relatively large amounts of excipient material
e.g. water or a saline solution. Accordingly, a given size
container could include a wide range of different doses by varying
drug concentration.
[0128] Drug containers may include indices which may be electronic
and may be connected to a power source such as a battery. When the
indices are in the form of visually perceivable numbers, letters or
any type of symbol capable of conveying information to the patient.
Alternatively, the indices may be connected to a power source such
as a battery when the indices are in the form of magnetically,
optically or electronically recorded information which can be read
by a drug dispensing device which in turn provides visual or audio
information to the user. The indices can be designed for any
desired purpose but in general provide specific information
relating to the day and/or time when the drug within a container
should be administered to the patient. Such indices may record,
store and transfer information to a drug dispensing device
regarding the number of doses remaining in the container. The
containers may include labeling which can be in any format and
could include days of the month or other symbols or numbers in any
variation or language.
[0129] In addition to disclosing specific information regarding the
day and time for drug delivery the indices could provide more
detailed information such as the amount of insulin dispensed from
each container which might be particularly useful if the containers
included different amounts of insulin. The device may dispense all
or any desired percentage amount (1-100%) of the insulin in the
container. The device keeps a record of the amount dispensed and
the container can be reused within a given period of time (e.g., 2
hours or less) to dispense the remainder of the insulin in a given
container. However, it is preferable to discard a container after
use even if all the formulation is not expelled. This ensures
freshness and reduces contamination. Further, magnetic, optical
and/or electronic indices could have new information recorded onto
them which information could be placed there by the drug dispensing
device. For example, a magnetic recording means could receive
information from the drug dispensing device indicating the precise
time (and amount) which the insulin was actually administered to
the patient. In addition to recording the time of delivery the
device could monitor the expected efficacy of the delivery based on
factors such as the inspiratory flow rate which occurred following
the initial release of insulin. The information recorded could then
be read by a separate device, interpreted by the care-giver and
used to determine the usefulness of the present treatment
methodology. For example, if the glucose levels of the patient did
not appear to be responding well but the recorded information
indicating that the patient had taken the drug at the wrong time or
that the patient had misdelivered drug by changing inspiratory flow
rate after initial release it might be determined that further
education in patient use of the device was needed but that the
present dosing methodology might well be useful. However, if the
recordings indicated that the patient had delivered the aerosolized
insulin using the proper techniques and still not obtained the
correct results (e.g. acceptable glucose levels) another dosing
methodology might be recommended. The method of treating diabetes
mellitus may be carried out using a hand-held, portable device
comprised of (a) a device for holding a disposable package
comprised of at least one but preferably a number of drug
containers, (b) a propellant or a mechanical mechanism for moving
the contents of a container through a porous membrane (c) a monitor
for analyzing the inspiratory flow rate and volume of a patient,
and (d) a switch for automatically releasing or firing the
mechanical means after the inspiratory flow and/or volume reaches a
threshold level. The device may also include a transport mechanism
to move the package from one container to the next with each
container and its porous membrane being disposed of after use.
Containers are preferably used only 1,2,3 or 4 times, at most. If
used more than once, the remainder in the container is used in 2
hours or less and/or disposed of. The entire device is
self-contained, light weight (less than 1 kg preferably less than
0.5 kg loaded) and portable.
[0130] The device may include a mouth piece at the end of the flow
path, and the patient inhales from the mouth piece which causes an
inspiratory flow to be measured within the flow path which path may
be in a non-linear flow-pressure relationship. This inspiratory
flow causes an air flow transducer to generate a signal. This
signal is conveyed to a microprocessor which is able to convert,
continuously, the signal from the transducer in the inspiratory
flow path to a flow rate in liters per minute. The microprocessor
can further integrate this continuous air flow rate signal into a
representation of cumulative inspiratory volume. At an appropriate
point in the inspiratory cycle, the microprocessor can send a
signal to an actuation means (and/or a vibration device below the
resonance cavity). When the actuation means is signaled, it causes
the mechanical means (by pressure and/or vibration) to move drug
from a container on the package into the inspiratory flow path of
the device and ultimately into the patient's lungs. After being
released, the drug and carrier will pass through a porous membrane,
which can be vibrated to aerosolize the formulation and thereafter
enter the lungs of the patient.
[0131] It is important to note that the firing threshold of the
device is not based on a single criterion such as the rate of air
flow through the device or a specific time after the patient begins
inhalation. The firing threshold is preferably based on repeating
the firing at the same flow rate and volume. This means that the
microprocessor controlling the device takes into consideration the
instantaneous air flow rate as well as the cumulative inspiratory
flow volume. Both are simultaneously considered together in order
to determine the optimal point in the patient's inspiratory cycle
most preferable in terms of (1) reproducibly delivering the same
amount of drug to the patient with each release of drug by
releasing drug at the same point each time and (2) maximizing the
amount of drug delivered as a percentage of the total amount of
drug released by releasing with the parameters described
herein.
[0132] The device preferably includes a means for recording a
characterization of the inspiratory flow profile for the patient
which is possible by including a microprocessor in combination with
a read/write memory means and a flow measurement transducer. By
using such devices, it is possible to change the firing threshold
at any time in response to an analysis of the patient's inspiratory
flow profile, and it is also possible to record drug dosing events
over time. In a particularly preferred embodiment the
characterization of the inspiratory flow can be recorded onto a
recording means associated with disposable package.
[0133] The details of a drug delivery device which includes a
microprocessor and pressure transducer of the type which may be
used in connection with the present invention are described and
disclosed within U.S. Pat. No. 5,404,871, issued Apr. 11, 1995 and
U.S. Pat. No. 5,450,336, issued Sep. 12, 1995 incorporated in their
entirety herein by reference, and specifically incorporated in
order to describe and disclose the microprocessor and program
technology used therewith. The pre-programmed information is
contained within a nonvolatile memory which can be modified via an
external device. In another embodiment, this pre-programmed
information is contained within a "read only" memory which can be
unplugged from the device and replaced with another memory unit
containing different programming information. In yet another
embodiment, a microprocessor, containing read only memory which in
turn contains the pre-programmed information, is plugged into the
device. For each of these embodiments, changing the programming of
the memory device readable by a microprocessor will radically
change the behavior of the device by causing the microprocessor to
be programmed in a different manner. This is done to accommodate
different insulin formulation and for different types of treatment,
e.g., patients with different types of diabetes.
[0134] After dosing a patient with insulin it is desirable to
measure glucose (invasively or non-invasively) and make adjustments
as needed to obtain the desired glucose level. In accordance with
all methods the patient does not push a button to release drug. The
drug is released automatically by signals from the microprocessor
using measurements obtained.
[0135] The doses administered are based on an assumption that when
intrapulmonary delivery methodology is used the efficiency of the
delivery is at a known percent amount, e.g., approximately 20% to
50% or more and adjustments in the amount released in order to take
into account the efficiency of the device. The differential between
the amount of insulin actually released from any device and the
amount actually delivered to the patient varies due to a number of
factors. In general, devices used with the present invention can
have an efficiency as low as 10% and as high as 50% or more meaning
that as little as 10% of the released insulin may actually reach
the circulatory system of the patient and as much as 50% or more
might be delivered. The efficiency of the delivery will vary
somewhat from patient to patient and must be taken into account
when programming the device for the release of insulin. In general,
a conventional metered (propellant-driven) dose inhaling device is
about 10% efficient.
[0136] One of the features and advantages of the present invention
is that the microprocessor can be programmed to take a variety of
different criteria into consideration with respect to dosing times.
Specifically, the microprocessor can be programmed so as to include
a minimum time interval between doses i.e. after a given delivery
another dose cannot be delivered until a given period of time has
passed. Secondly, the timing of the device can be programmed so
that it is not possible to exceed the administration of a set
maximum amount of insulin within a given time. For example, the
device could be programmed to prevent dispersing more than 5 units
of insulin within one hour. More importantly, the device can be
programmed to take both criteria into consideration. Thus, the
device can be programmed to include a minimum time interval between
doses and a maximum amount of insulin to be released within a given
time period. For example, the microprocessor could be programmed to
allow the release of a maximum of 5 units of insulin during an hour
which could only be released in amounts of 1 unit with each release
being separated by a minimum of five minutes.
[0137] Additional information regarding dosing with insulin via
injection can be found within Harrison's--Principles of Internal
Medicine (most recent edition) published by McGraw Hill Book
Company, New York, incorporated herein by reference to disclose
conventional information regarding dosing insulin via
injection.
[0138] Another feature of the device is that it may be programmed
not to release drug if it does not receive a signal transmitted to
it by a transmitter worn by the intended user. Such a system
improves the security of the device and prevents misuse by
unauthorized users such as children.
[0139] The microprocessor of the invention can be connected to
external devices permitting external information to be transferred
into the microprocessor of the invention and stored within the
non-volatile read/write memory available to the microprocessor. The
microprocessor of the invention can then change its drug delivery
behavior based on this information transferred from external
devices such as a glucose monitoring device. All of the features of
the invention are provided in a portable, programmable,
battery-powered, hand-held device for patient use which has a size
which compares favorably with existing metered dose inhaler
devices.
[0140] Different mechanisms will be necessary in order to deliver
different formulations, such as a dry powder without any
propellant. A device could be readily designed so as to provide for
the mechanical movement of a predetermined amount of dry powder to
a given area. The dry powder would be concealed by a gate, which
gate would be opened in the same manner described above, i.e., it
would be opened when a predetermined flow rate level and cumulative
volume have been achieved based on an earlier monitoring event.
Patient inhalation or other source of energy such as from
compressed gas or a mechanical device would then cause the dry
powder to form a dry dust cloud and be inhaled.
[0141] In addition to monitoring glucose levels in order to
determine proper insulin dosing, the microprocessor of the present
invention is programmed so as to allow for monitoring and recording
data from the inspiratory flow monitor without delivering drug.
This is done in order to characterize the patient's inspiratory
flow profile in a given number of monitoring events, which
monitoring events preferably occur prior to dosing events. After
carrying out a monitoring event, the preferred point within the
inspiratory cycle for drug delivery can be calculated. This
calculated point is a function of measured inspiratory flow rate as
well as calculated cumulative inspiratory flow volume. This
information is stored and used to allow activation of the valve
when the inhalation cycle is repeated during the dosing event.
Those skilled in the art will also readily recognize that different
mechanisms will be necessary in order to deliver different
formulations, such as a dry powder without any propellant. A device
could be readily designed so as to provide for the mechanical
movement of a predetermined amount of dry powder to a given area.
The dry powder would be concealed by a gate, which gate would be
opened in the same manner described above, i.e., it would be opened
when a predetermined flow rate level and cumulative volume have
been achieved based on an earlier monitoring event. Patient
inhalation would then cause the dry powder to form a dry dust cloud
and be inhaled. Dry powder can also be aerosolized by compressed
gas, and a solution can be aerosolized by a compressed gas released
in a similar manner and then inhaled.
EXAMPLES
[0142] The following examples are put forth so as to provide those
of ordinary skill in the art with a complete disclosure and
description of how to make and use various constructs and perform
the various methods of the present invention and are not intended
to limit the scope of what the inventors regard as their invention.
Efforts have been made to ensure accuracy with respect to numbers
used (e.g. amounts, concentrations, particular components, etc.)
but some deviations should be accounted for.
Example 1
Administration of Regular Recombinant Human Insulin
[0143] A study was performed to determine the influence of
different inhalation maneuvers: deep (V.sub.H) and shallower
(V.sub.L) inhalation. Deep inhalations required the patients to
inhale as much as possible (e.g., 4-5 liters) and shallow
inhalation were about half that (e.g. 2-2.5 liters) following the
administration of aerosolized drug). The study was performed using
five healthy, fasting male subjects. To each of the subjects, 250
U/ml of a 7.4 pH human zinc insulin formulation was administered
using three methods: subcutaneous administration, deep inhalation
administration, or shallow inhalation administration.
[0144] The study was performed using five healthy, fasting male
subjects. 250 U/ml of a 3.5 pH human insulin formulation was
administered to each of the subjects using three methods:
subcutaneous administration, V.sub.H inhalation administration and
V.sub.L administration. Subcutaneous administration of the insulin
consisted of an injection of a predetermined dosage into the
subcutaneous region of the abdominal area. Aerosol administration
to each subject was performed using a unit-dosed, breath-actuated
microprocessor controlled device (AERx.TM.), such as the device
disclosed in the present application (see U.S. Pat. No. 5,660,166
issued Aug. 26, 1997).
[0145] Serial serum blood samples were taken from each subject for
the analysis of plasma glucose. The inhalation method resulted in a
more rapid initial chance, and experienced a plateau at
approximately a -20% change in plasma glucose. The subcutaneous
administration resulted in a slower response initially, achieving a
later plateau at approximately a -25 % change in glucose
response.
[0146] The pharmacokinetic parameters--C.sub.max the maximum serum
insulin concentration achieved in each subject, and T.sub.max the
amount of time needed for subjects to reach C.sub.max after
administration were determined for each subject, and (summarized in
Table 1). The deep inhalation method showed a 10-fold decrease in
T.sub.max.
1TABLE 1 Inhaled human insulin: effect of mode of administration
Parameter (mean .+-. SD) AERx-V.sub.H AERx-V.sub.L T.sub.max (min)
5 .+-. 6 51 .+-. 18 C.sub.max (.mu.U/ml) 26.7 .+-. 9.1 20.9 .+-.
8.1
[0147] Serum insulin profiles of each of the three modes of
administration show similar peaks before tapering off over a three
hour period (FIG. 1). The AERx device V.sub.H administration peaks
much sooner and at a higher concentration than the other methods,
peaking at approximately 26 .mu.U/ml at about 20 minutes. The AERx
device V.sub.L administration results in a slightly later and lower
peak at one hour. Subcutaneous injection also results in a later
peak.
[0148] The study conducted with the regular zinc insulin pH 7.4
showed the importance of the breathing technique in the
administration of this particular insulin formulation, as
controlled, deep breathing promoted rapid insulin absorption.
[0149] The results of experiment I demonstrate one aspect of the
present invention. Specifically, the results show that it is
important to control the inhaled volume when inhaling an
aerosolized dose of regular insulin. Thus, one aspect of the
invention involves measuring a patient's inhaled volume at delivery
in order (1) repeatedly deliver with the same inhaled volume each
time to ensure repeatability of dosing; and (2) prompt the patient
to inhale a high volume, e.g. 80% plus or minus 15% of lung
capacity with each inhalation. The prompting to inhale a high
volume can be carried out by sending a signal to the patient from a
device which measures the inspiratory volume during drug
delivery.
Example 2
Determination of Efficacy of Administration of Aerosolized Human
Insulin Lispro
Modes of Administration
[0150] Pharmacokinetic parameters associated with the two modes of
insulin administration, inhalation of aerosolized insulin lispro
and subcutaneous injection of insulin lispro, were determined to
compare the efficacy (bioeffectiveness in reducing glucose levels)
and speed of each. The study was performed using nine healthy,
fasted male subjects.
[0151] Aerosol administration to each subject was performed using
the AERx.TM. device. Administration was done using both deep
(V.sub.H) and shallower (V.sub.L) inhaled administration--in 5 out
of 9 subjects. Subcutaneous administration of the insulin lispro
consisted of an injection of a predetermined dosage into the
subcutaneous region of the abdominal area. Serial serum blood
samples were taken from each subject for the analysis of plasma
glucose and serum insulin.
[0152] The pharmacokinetic parameters C.sub.max and T.sub.max were
determined for each subject. (Table 2). T.sub.max was earlier
following inhalation administration of insulin lispro, indicating a
more rapid absorption from the lung as compared to SC
administration. Thus, the mode of inhalation (V.sub.H or V.sub.L)
did not appear to significantly effect pharmacokinetics of the
delivery of inhaled insulin lispro as compared to the affect of
V.sub.L and V.sub.H on the delivering of regular insulin.
2TABLE 2 Pharmacokinetic parameters after insulin lispro
administration (systematic study, n = 5) Parameter AERx-V.sub.H
AERx-V.sub.L (mean .+-. SD) (0.3 U/kg) (0.3 U/kg) T.sub.max (min) 9
.+-. 2 18 .+-. 15 C.sub.max (.mu.U/ml) 46 .+-. 12 49 .+-. 12
[0153] In contrast to data obtained for aerosolized delivery of
regular human insulin, the mode of inhalation did not lead to
changes in the serum insulin levels following administration of
insulin lispro - compare FIGS. 1 and 2.
[0154] The results in Tables 1 and 2 can be compared to show that
the total inhaled volume at delivery greatly effects results when
administering regular human recombinant insulin (Table 1) but has
much less of an effect when administering insulin lispro. As shown
in FIG. 2, the blood concentration versus time insulin lispro is
virtually the same for both the V.sub.H and V.sub.L maneuvers. This
surprising result indicates that repeatability of dosing can be
more readily obtained with the administration of insulin lispro by
inhalation as compared with conventional insulin by inhalation. The
results shown here indicate that when delivering insulin (not
monomeric insulin) by inhalation the total inhaled volume should be
about the same at each delivery to obtain repeatable delivery.
Thus, referring to FIG. 3, insulin is released at the same point 1
for each release and then the patient continues to inhale to the
same point 3 or 4. Preferably, the patient continues to inhale to
point 4 or higher each time to obtain repeatable delivery.
[0155] The foregoing invention has been described in some detail by
way of illustration and example for purposes of clarity of
understanding. The instant invention is shown herein in what is
considered to be the most practical and preferred embodiments. It
is recognized, however, that departures may be made therefrom which
are within the scope of the invention and that obvious
modifications will occur to one skilled in the art upon reading
this disclosure. Accordingly, the invention is limited only by the
following claims.
* * * * *