U.S. patent application number 11/492153 was filed with the patent office on 2007-02-01 for peroxide removal from drug delivery vehicle.
This patent application is currently assigned to ALZA CORPORATION. Invention is credited to John Patrick Carr, Michael A. DesJardin, Gunjan Junnarkar.
Application Number | 20070027105 11/492153 |
Document ID | / |
Family ID | 37695158 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070027105 |
Kind Code |
A1 |
Junnarkar; Gunjan ; et
al. |
February 1, 2007 |
Peroxide removal from drug delivery vehicle
Abstract
The present invention is related to methods for lowering
peroxide levels in sucrose acetate isobutyrate formulations and to
composition used in and formed by such methods.
Inventors: |
Junnarkar; Gunjan; (Palo
Alto, CA) ; DesJardin; Michael A.; (Sunnyvale,
CA) ; Carr; John Patrick; (Sunnyvale, CA) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
CIRA CENTRE, 12TH FLOOR
2929 ARCH STREET
PHILADELPHIA
PA
19104-2891
US
|
Assignee: |
ALZA CORPORATION
MOUNTAIN VIEW
CA
|
Family ID: |
37695158 |
Appl. No.: |
11/492153 |
Filed: |
July 24, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60702546 |
Jul 26, 2005 |
|
|
|
Current U.S.
Class: |
514/53 ; 514/777;
536/119 |
Current CPC
Class: |
A61K 9/0024 20130101;
A61P 35/00 20180101; C07H 1/06 20130101; A61K 38/21 20130101; A61K
47/26 20130101; A61K 31/7024 20130101; A61K 9/10 20130101; C07H
13/04 20130101; A61K 9/0004 20130101 |
Class at
Publication: |
514/053 ;
536/119; 514/777 |
International
Class: |
A61K 31/7024 20070101
A61K031/7024; C07H 13/02 20060101 C07H013/02; A61K 47/00 20060101
A61K047/00 |
Claims
1. A method of treating a sucrose acetate isobutyrate formulation
to be used as a drug delivery vehicle comprising adding to the
formulation an amount of bisulfite salt effective to substantially
remove peroxides, the bisulfite salt comprising sodium
metabisulfite, potassium metabisulfite, sodium bisulfite, or
potassium bisulfite, or a mixture thereof.
2. The method of claim 1, wherein the bisulfite salt is sodium
metabisulfite.
3. The method of claim 1, wherein the method removes peroxide to a
level that is 10% or less than the level present I the formulation
before addition of the bisulfite salt.
4. The method of claim 1, wherein the method removes peroxide to
result in a formulation having less than 5 ppm of peroxide.
5. The method of claim 1, wherein the formulation serves as a drug
delivery vehicle for use with an osmotically pump-driven
implantable device.
6. The method of claim 1, wherein the adding step comprises mixing
a solution of bisulfite salt with the sucrose acetate isobutyrate
formulation.
7. The method of claim 1, wherein the formulation further comprises
a cosolvent comprising hexane, ethyl acetate, ethanol, benzyl
benzoate, N-methyl pyrrolidone, or iso-propyl alcohol, or a
combination thereof.
8. The method of claim 7, wherein the cosolvent is hexane or ethyl
acetate.
9. The method of claim 7, further comprising vacuum treating the
formulation to remove the cosolvent.
10. The method of claim 1, further comprising washing the
formulation with water to remove the bisulfite salt.
11. The method of claim 1, further comprising washing the
formulation with glycerin to remove the bisulfite salt.
12. The method of claim 10, further comprising drying the
formulation using magnesium sulfate, calcium chloride anhydrous,
calcium sulfate anhydrous, activated silica gel, phosphorous
pentoxide, or vacuum, or combinations thereof.
13. The method of claim 10, further comprising drying the
formulation using magnesium sulfate.
14. The method of claim 10, wherein the steps of adding a bisulfite
salt, washing the formulation, and drying the formulation are
repeated at least once.
15. A drug delivery vehicle for a drug that is to be delivered in
vivo comprising sucrose acetate isobutyrate having substantially
reduced levels of peroxide, the drug delivery vehicle being treated
with an amount of bisulfite salt effective to substantially reduce
levels of peroxide in said drug delivery vehicle, the bisulfite
salt comprising sodium metabisulfite, potassium metabisulfite,
sodium bisulfite, or potassium bisulfite, or a combination
thereof.
16. The drug delivery vehicle of claim 15, wherein the bisulfite
salt is sodium metabisulfite.
17. The drug delivery vehicle of claim 15, wherein the prolonged
stability comprises reduced oxidation, reduced deamidation, or
reduced aggregation of the drug.
18. The drug delivery vehicle of claim 15, wherein the prolonged
stability is reduced oxidation of the drug.
19. The drug delivery vehicle of claim 15, wherein the
substantially reduced levels of peroxide are levels at or below 20
ppm in the drug delivery vehicle.
20. The drug delivery vehicle of claim 15, wherein the
substantially reduced levels of peroxide are levels at or below 10
ppm in the drug delivery vehicle.
21. The drug delivery vehicle of claim 15, wherein the
substantially reduced levels of peroxide are levels at or below 5
ppm in the drug delivery vehicle.
22. The drug delivery vehicle of claim 15, wherein the treatment
with the bisulfite salt comprises removal of the bisulfite salt
from the drug delivery vehicle.
23. The drug delivery vehicle of claim 15, wherein the vehicle is
adapted to serve as a drug depot.
24. The drug delivery vehicle of claim 15, wherein the vehicle is
adapted for delivery from an implantable device.
25. The drug delivery vehicle of claim 24, wherein the implantable
device is an osmotically pump-driven implantable device.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
application No. 60/702,546, filed Jul. 26, 2005, which is
incorporated herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to methods for reducing
peroxide levels in non-polymeric preparations and to compositions
used in and prepared by such methods.
BACKGROUND OF THE INVENTION
[0003] Sucrose acetate isobutyrate ("SAIB") is a hydrophobic liquid
with limited water solubility. It is soluble in a large number of
biocompatible solvents. SAIB has an unusual property--it undergoes
a dramatic change in viscosity with small additions of heat or with
the addition of solvents. It is a very viscous liquid, having a
viscosity of approximately 3200 poise at 37.degree. C. SAIB is
produced by the controlled esterification of natural sugar
(sucrose) with acetic and isobutyric anhydrides. SAIB metabolizes
to sucrose, acetic acid and isobutyric acid.
[0004] SAIB is orally non-toxic and is currently used to stabilize
emulsions in the food industry. In one example, SAIB is commonly
found in the beverage industry, where it is used as a weighting
agent to help stabilize the final beverage formula. Also, SAIB has
been reported to be useful as a gelling system-type drug excipient
that allows for sustained or controlled release of drugs. When in
solution or in an emulsion, SAIB can be applied via injection or an
aerosol spray. SAIB is compatible with cellulose esters and other
polymers that can affect the rate of delivery of the substance. In
one example, SAIB is the main ingredient for the SABER drug
delivery system, which also consists of a pharmaceutically
acceptable solvent.
[0005] Drug delivery systems, including SAIB delivery systems, are
still confronted by various issues of drug instability, as such
systems are considered for longer and longer drug delivery
durations. Drug instability can occur via a number of factors,
including denaturation, precipitation, oxidation, aggregation, and
others. In particular, a number of excipients used to facilitate
delivery and release of drugs have peroxides or are susceptible to
the formation of peroxides, which may lead to oxidation of active
ingredient in the formulation. In the example of SAIB, the presence
of peroxides is deleterious to a drug incorporated in an SAIB drug
formulation as the drug is likely to undergo oxidative degradation.
Thus, in order to formulate any drug formulation based on SAIB that
provides enough of a stable environment to facilitate the delivery
of a drug, the peroxide levels must be reduced.
[0006] There is no known process for removal of peroxides from SAIB
at present, despite availability of processes for the removal of
peroxides from other materials such as polymers. Therefore, there
still remains a need for a drug formulation of SAIB having improved
properties to reduce the degradation of the drug therein.
SUMMARY OF THE INVENTION
[0007] An aspect of the present invention comprises methods of
treating sucrose acetate isobutyrate (SAIB) formulations to be used
as drug delivery vehicles comprising adding to the formulations an
amount of bisulfite salt effective to substantially remove
peroxides, the bisulfite salt comprising sodium metabisulfite,
potassium metabisulfite, sodium bisulfite, or potassium bisulfite,
or a mixture thereof.
[0008] In another aspect of the present invention, provided are
drug delivery vehicles adapted to provide prolonged stability of a
drug that is to be delivered in vivo comprising sucrose acetate
isobutyrate having substantially reduced levels of peroxide, the
drug delivery vehicle being treated with an amount of bisulfite
salt effective to substantially reduce levels of peroxide in said
drug delivery vehicle, the bisulfite salt comprising sodium
metabisulfite, potassium metabisulfite, sodium bisulfite, or
potassium bisulfite, or a combination thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention is illustrated by way of example and is not
intended to be limited by the accompanying figures.
[0010] FIG. 1 illustrates a bar graph of the results of Study
I--Stability of omega-interferon in untreated SAIB.
[0011] FIG. 2 illustrates a bar graph of the results of Study
IIa--Stability of omega-interferon in alumina treated SAIB.
[0012] FIG. 3 illustrates a bar graph of the results of Study
IIb--Stability of omega-interferon in alumina treated SAIB.
[0013] FIG. 4 illustrates a bar graph of the results of Study
III--Stability of omega-interferon in untreated SAIB.
[0014] FIG. 5 illustrates a bar graph of the results of Study
VIb--Stability of omega-interferon in untreated SAIB.
[0015] FIG. 6 illustrates a bar graph of the results of Study
VIa--Stability of omega-interferon in sodium metabisulfite treated
SAIB.
[0016] FIG. 7 illustrates a bar graph that provides comparisons of
oxidation of omega-IFN in sodium metabisulfite treated and
untreated SAIB.
[0017] FIG. 8 illustrates an osmotically pump-driven implantable
device, Duros.RTM. being an example, that facilitates in vivo
delivery of an active agent in an SAIB vehicle.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0018] In an aspect of the present invention, provided are methods
of treating sucrose acetate isobutyrate formulations (SAIB) that
are to be used as drug delivery vehicles comprising adding an
amount of a bisulfite salt effective for substantially removing
peroxide from the formulations, the bisulfite salt comprising
sodium metabisulfite, potassium metabisulfite, sodium bisulfite, or
potassium bisulfite, or a combination thereof. Preferably, the
bisulfite salt is sodium metabisulfite. A ratio ranging from about
1:1 to about 1:4 (weight:volume) SAIB:aqueous solution of bisulfite
salt ("aqueous bisulfite salt") can be used. Preferably, the
bisulfite salt is a metabisulfite salt. In some embodiments, the
bisulfite salt is preferably sodium metabisulfite. Preferably, the
ratio of the aqueous bisulfite salt to SAIB is 1:1. In one example,
to purify 1 kg of SAIB, a volume of sodium metabisulfite solution
can be made up to 1 liter, and an approximate proportion of 1:1 of
SAIB:aqueous sodium metabisulfite was used. The aqueous bisulfite
salt in SAIB can be from about 0.1% weight to volume of water (w/v)
to about 50% w/v; preferably, from about 0.5% w/v to about 30% w/v.
In some embodiments, the aqueous bisulfite salt is preferably from
about 1% w/v to about 15% w/v. In some embodiments, the aqueous
bisulfite salt is about 5% w/v solution in water.
[0019] The method removes peroxide to a level that is at least less
than 50% of the levels before the method, or starting levels, and,
preferably, less than 20% of the starting levels. In some
embodiments, peroxide is removed to less than 10% of the starting
levels. While in some embodiments, the method removes peroxide to a
level that is less than 5% of the starting levels. Furthermore, the
method can remove peroxide so that the resulting SAIB formulation
contains peroxide in amounts less than 20 ppm, and, preferably,
less than 10 ppm. In some embodiments, the method removes peroxide
to result in an SAIB formulation containing less than 5 ppm. In
some embodiments, the resulting SAIB formulation from this method
can serve as a drug delivery vehicle for use with a medical
delivery device, including a drug eluting stent, a catheter, or
other drug delivery implants. In one example, the SAIB formulation
can be loaded into an osmotically pump-driven implantable device of
the type disclosed in U.S. Pat. No. 6,395,292, for example.
Preferably, the osmotically pump-driven implantable device is a
Duros.RTM. device (Alza Corporation, Mountain View, Calif.). In
other embodiments, the SAIB formulation can serve as a drug depot
for drug delivery.
[0020] In some embodiments, the step of adding the bisulfite salt
comprises mixing a solution of the bisulfite salt with the sucrose
acetate isobutyrate formulation. The SAIB formulation can be
further comprised of a cosolvent, which can be selected from a
number of solvents including pharmaceutically acceptable solvents,
e.g., hexane, ethyl acetate, ethanol, benzyl benzoate, N-methyl
pyrrolidone, and iso-propyl alcohol, among others. Preferably, the
cosolvent is hexane or ethyl acetate. In some embodiments, the
methods further comprise vacuum treating the formulation to remove
the cosolvent. Also, some embodiments comprise the additional step
of removing bisulfite salt from the formulation. This removal step
comprises washing the formulation with water to remove the
bisulfite salt. In the embodiments that incorporate the washing
step, a further step of drying the formulation over magnesium
sulfate can be utilized to remove the water. Alternatively, calcium
chloride anhydrous, calcium sulfate anhydrous, activated silica
gel, phosphorous pentoxide, or drying under vacuum, or a
combination thereof can be used to also remove the water. In
alternative embodiments, glycerin can be used to wash the
bisulfite-added formulation to remove the bisulfite salt.
Afterwards, residual glycerin can be removed by washing with water
and then drying to remove water.
[0021] In some aspects of the present invention, the methods of
substantially removing peroxide from a sucrose acetate isobutyrate
formulation (SAIB) comprising the steps of adding the aqueous
bisulfite salt, washing the formulation, and drying the formulation
are repeated at least once. The steps can be repeated to further
reduce the levels of peroxide in the SAIB formulation.
[0022] In another aspect, the present invention includes a drug
delivery vehicle comprising SAIB that provides for prolonged
stability of a drug that is to be delivered by maintaining
substantially reduced levels of peroxide, the drug delivery vehicle
being treated with sodium metabisulfite. The prolonged stability
comprises reduced oxidation, deamidation, or aggregation, e.g.,
dimerization, of the drug over extended periods of time in which
drug is within environment of delivery vehicle. Preferably the
prolonged stability is reduced oxidation. The extended periods of
time can be periods from about one week to a few months, and up to
about a year. Preferably, the prolonged stability is evidenced by
significant improvements in oxidation, deamidation, or aggregation
levels of the drug when the delivery vehicle has been treated with
a bisulfite salt versus untreated delivery vehicle. In some
preferred embodiments, the prolonged stability is characterized as
about 50% less oxidation, about 33% less deamidation, or about 75%
less dimerization as compared to untreated delivery vehicles. The
drug can be selected from any known and desired biomolecular
material that can act as therapeutics and other therapeutic active
agents that are susceptible to oxidative degradation. As it is used
herein, the term "biomolecular material" refers to peptides,
polypeptides, proteins, nucleic acids, viruses, antibodies, small
molecules susceptible to oxidation, and any other naturally
derived, synthetically produced, or recombinantly produced active
agent that includes nucleic or amino acid. In some embodiments, for
example, drugs can be selected from among the following: a steroid,
NSAIDS, peptides, proteins such as growth factors or hormones,
anti-tumor agents, antibiotics, analgesics, local anesthetics,
antiviral agents, antipsychotics, anticoagulants, oligonucleotides
for gene therapy, active small molecules, and others.
[0023] As used herein, the term "removing" and all variations
thereof, refer to decreasing by any measurable degree the level of
peroxide present in a drug formulation. The term "substantially
removing" is used herein to describe a dramatic decrease in the
level of peroxide present in a drug formulation, such as SAIB
formulation. The dramatic decrease is at least 50% of original
levels (levels before treatment) and in some instances is 10% of
original levels. In preferred aspects of the present invention, the
"substantial removal" describes a decrease to less than 5% of
original levels.
[0024] As used herein, the term "drug delivery vehicle" or
"delivery vehicle" refers to a formulation that is biocompatible
and used to carry a drug without reacting with the same drug. Also,
the vehicle does not alter or minimally alters the activity of the
drug. Furthermore, the vehicle allows for the transport of the drug
in vivo and eventual delivery of the drug to a biological site for
therapeutic effect.
[0025] As used herein, the term "prolonged stability" is used to
refer to the stabilizing effect of the drug delivery vehicles of
the present invention on the carried drug. Prolonged stability can
be evidenced by significant improvements in oxidation, deamidation,
or aggregation of the drug over extended periods of time.
EXAMPLES
[0026] Different approaches were investigated for removal of
peroxides from SAIB, as indicated in Table 1.
Preparation of Suspension
[0027] Each of the experiments involved protein particles
consisting of omega-interferon, which were suspended in SAIB at a
particle loading of either 4% or 10% by weight. The suspensions
were prepared in a dry box under nitrogen at 45.degree. C. The
suspension was mixed for 15 minutes while maintaining the
temperature. Suspension mixing was performed by hand. Aliquots from
the prepared suspensions were transferred to clear crimp-top glass
vials and sealed under nitrogen. Each aliquot contained at least
six milligrams of protein to allow for stability testing in
triplicate. These samples were stored in an oven at 40.degree. C.
Samples were withdrawn at regular intervals (as indicated in Table
1) and analyzed for omega-interferon content and purity was
assessed using reverse phase HPLC and size exclusion
chromatography.
Size Exclusion Chromatography
[0028] Size exclusion chromatography (SEC) was used to monitor the
omega-interferon content and purity in the formulations. The
percentages of monomer and dimer in the formulation were quantified
using SEC. The stability of omega-interferon was judged by using a
stability indicating chromatographic technique based on reverse
phase HPLC (rp-HPLC). This technique was used to monitor the
oxidation, deamidation and formation of an unknown species of
omega-interferon in the formulations. The peroxide content of the
vehicle was determined using EP 2002, 2.5.5 (Method A with auto
titration). See Extra Pharmacopoeia, 2002 Ed. Content and purity
assay of omega-interferon by size exclusion chromatography
(SEC).
Reverse Phase High Performance Liquid Chromatography
[0029] Purity assay and identity of omega-interferon recombinant in
suspension systems by reverse phase high performance liquid
chromatography (rp-HPLC).
[0030] The stability of omega-interferon was monitored in two
different lots of untreated SAIB (as received) and in treated SAIB
(removal of peroxides), when treatment was applied.
[0031] The studies are outlined below:
[0032] Study I: Stability in untreated SAIB (lot #TD1030507) for 2
weeks
[0033] Study IIa: Treatment of SAIB (lot #TD1030507) with neutral
alumina by heating and stability in this treated SAIB for 4
weeks
[0034] Study IIb: Treatment of SAIB (lot #TD1030507) with neutral
alumina in presence of ethanol and stability in this treated SAIB
for 4 weeks
[0035] Study III: Stability in untreated SAIB (lot #TD2032663) for
2 weeks
[0036] Study IV: Treatment of SAIB (lot #TD2032663) with basic
alumina by heating
[0037] Study V: Treatment of SAIB (lot #TD2032663) with 10% aqueous
methionine solution by heating
[0038] Study VIa: Treatment of SAIB (lot #TD2032663) with 5%
aqueous solution of sodium metabisulfite and stability in treated
SAIB for 8 weeks
[0039] Study VIb: Stability in untreated SAIB (lot #TD2032663) for
8 weeks TABLE-US-00001 TABLE 1 Details about stability studies of
omega-interferon in SAIB SAIB Particle Time Study # (Lot #)
Treatment loading points Tests I TD1030507 Untreated 4% 0, 4, 7,
SEC, RP-HPLC 14 days IIa TD1030507 Treated with neutral 10% 0, 2,
SEC, RP-HPLC alumina by heating 4 weeks IIb TD1030507 Treated with
neutral 10% 0, 2, SEC, RP-HPLC alumina using ethanol 4 weeks III
TD2032663 Untreated 10% 0, 1, SEC, RP-HPLC 2 weeks IV TD2032663
Treated with basic NA NA NA alumina by heating V TD2032663 Treated
with 10% NA NA NA aqueous solution of methionine VIa TD2032663
Treated with hexane 10% 0, 1, 2, 4, SEC, RP-HPLC and 8 weeks sodium
metabisulfite VIb TD2032663 Untreated 10% 0, 1, 2, 4, SEC, RP-HPLC
8 weeks
Materials and Equipment
[0040] The following tables, Table 2 and Table 3, provide a list of
materials and equipment that can be utilized to perform the
experiments described, below. TABLE-US-00002 TABLE 2 List of
materials Materials Spary dried omega-interferon particles SAIB,
Eastman Chemical Company Aluminum oxide (powder) Ethanol, absolute,
200 proof, AAPER Aluminum oxide, basic, standard activity I, 50-200
.mu.m, Sorbent Technologies Aluminum oxide, basic, Super I, 50-200
.mu.m, Sorbent Technologies Methionine, USP, Ph Eur, JP
[0041] TABLE-US-00003 TABLE 3 List of equipment Equipment Branson
Ultrasonic Cleaner Model 2510 VAC Dry Box Mettler AT261 Delta Range
Balance Mettler PJ3000 Balance Sartorius Genius Electronic
Analytical Balance Hot plate Oven (40.degree. C.) Millipore filter,
white hydrophilic, Durapore Disc, SLVP, 25 mm, 5 .mu.m PTFE
membrane filter, 0.2 .mu.m, Titan filtration systems
Example 1
[0042] Study I: Stability in Untreated SAIB (Lot #TD1030507) for 2
Weeks TABLE-US-00004 TABLE 4 Stability of omega-interferon in
untreated SAIB (lot #: 1030507) - Study I Analysis by RP-HPLC (n =
3)** Initial (t = 0) (AR 48452) 4 days 7 days 14 days (protein
particles)*** AR48424 AR48562 AR48450 Assay (%) NA 0.59* (0.02)
0.72 (0.00) 0.68 (0.00) % omega-IFN 93.37 (0.40) 89.06 (0.46) 87.65
(0.06) 87.67 (0.26) Purity % Oxidized 2.8 (0.71) 7.21 (0.88) 7.79
(1.09) 8.31 (0.10) % Deamidated 0.8 (0.02) 1.21 (0.00) 1.28 (0.01)
1.63 (0.03) % Unknown 3.03 (0.62) 2.25 (0.66) 3.27 (0.79) 2.39
(0.38) Analysis by SEC (n = 3)** Initial (AR 48452) 4 days 7 days
14 days (protein particles)*** AR48424 AR48562 AR48450 % Monomer
100.00 (0.00) 99.96 (0.01) 99.60 (0.02) 99.40 (0.00) % Dimer ND
0.04 (0.00) 0.38 (0.01) 0.58 (0.02) Unknown ND ND 0.01 (0.00) 0.01
(0.01) ND = Not detected, *sampled by scraping container walls, so
values might not be representative of the bulk **standard deviation
in parenthesis; ***protein particles - t = 0 for suspension
[0043] The preliminary stability study of omega interferon in
untreated SAIB (lot # TD1030507, peroxide value--71.4 ppm) was over
2 weeks. The results indicated that up to 8.31% of omega-interferon
was oxidized in two weeks, which corresponds to an increase of
5.51% with respect to particles (2.8% oxidation at t=0). See Table
4, FIG. 1. Furthermore, a small increase occurred in the percentage
of deamidated form (+0.83%) of omega-interferon and the dimer
(+0.58%). The high level of oxidation can be attributed to the high
peroxide content of SAIB.
Example 2
Study IIa and IIb: Stability of SAIB (Lot #TD1030507) Treated with
Neutral Alumina with Heating or Neutral Alumina in Presence of
Ethanol for 4 Weeks
Treatment of SAIB with Neutral Alumina with Heating
[0044] SAIB was heated to 75.degree. C. Alumina (15% w/w) was added
to the heated SAIB. The mixture was stirred for 40 minutes and
filtered though a 5.0 .mu.m filter at 75.degree. C. The treated
SAIB was then collected, sampled for peroxide testing, and used for
preparation of suspension for stability testing.
Treatment of SAIB with Neutral Alumina in Presence of Ethanol
[0045] SAIB was mixed with 15% absolute ethanol to reduce the
viscosity. Basic alumina (15% w/w) was added to the SAIB containing
ethanol. The resulting mixture was stirred for 1 hour and filtered
though a 0.2 .mu.m filter. The filtered SAIB was placed overnight
under vacuum at 60.degree. C. to remove the ethanol. This treated
SAIB was then collected, sampled for peroxide testing, and used for
preparation of suspension for stability testing. TABLE-US-00005
TABLE 5 Stability of omega-interferon in alumina treated SAIB ((lot
#: 1030507) - Studies IIa and IIb SAIB treated with neutral alumina
by heating - Study IIa Initial (t = 0) Initial (t = 0) 2 weeks 1
month (protein particles) AR 48570 AR 48572 AR 48565 Analysis by
RP-HPLC (n = 3)** Assay (%) NA 1.68 (0.01) 1.70 (0.00) 1.72 (0.01)
% omega-IFN Purity 89.08 (0.56) 87.56 (0.47) 83.90 (0.15) 82.97
(0.50) % Oxidized 1.72 (0.12) 3.45 (0.06) 6.85 (0.14) 7.39 (0.21) %
Deamidated 1.49 (0.01) 1.46 (0.03) 1.84 (0.03) 2.42 (0.05) %
Unknown 7.70 (0.45) 7.52 (0.45) 7.41 (0.01) 7.22 (0.46) Analysis by
SEC (n = 3)** % Monomer 100.00 (0.00) 100.00 (0.00) 99.89 (0.01)
99.50 (0.02) % Dimer trace 0.00 0.11 (0.01) 0.50 (0.02) Unknown
0.00 0.00 0.00 0.00 SAIB treated with neutral alumina using ethanol
- Study IIb Initial (t = 0) Initial (t = 0) 2 weeks 1 month
(protein particles) AR 48570 AR 48572 AR 48565 Analysis by RP-HPLC
(n = 3)** Assay (%) NA 1.66 (0.02) 1.70 (0.01) 1.70 (0.00) %
omega-IFN Purity 89.08 (0.56) 88.12 (0.49) 83.76 (0.09) 82.65
(0.19) % Oxidized 1.72 (0.12) 3.08 (0.07) 6.98 (0.12) 7.42 (0.10) %
Deamidated 1.49 (0.01) 1.47 (0.01) 1.88 (0.02) 2.45 (0.09) %
Unknown 7.70 (0.45) 7.32 (0.48) 7.38 (0.02) 7.48 (0.05) Analysis by
SEC (n = 3)** % Monomer 100.00 (0.00) 100.00 (0.00) 99.87 (0.01)
99.43 (0.02) % Dimer trace 0.00 0.13 (0.01) 0.57 (0.02) Unknown
0.00 0.00 0.00 0.00 **standard deviation in parenthesis
[0046] The stability of omega-interferon in alumina treated SAIB
was tested. After one month in the neutral alumina treated SAIB
(Study IIa and IIb), oxidation of omega-interferon increased by
about 5.7% for both IIa and IIb. This indicates that alumina
treatment of SAIB did not improve the stability of omega-interferon
in SAIB. See Table 5. In addition, this analysis is also reflected
in the high peroxide content of alumina treated SAIB (66.3 and 62.9
ppm, respectively). Treatment with neutral alumina was not
effective in decreasing peroxide content.
Example 3
[0047] Study III: Stability in Untreated SAIB (Lot #TD2032663) for
2 Weeks TABLE-US-00006 TABLE 6 Stability of omega-interferon in
untreated SAIB ((lot #: 2032663) - Study III Analysis by RP-HPLC (n
= 3)** Initial (t = 0) (AR 48217 Initial (t = 0) 1 week 2 weeks
(protein particles) AR 49640 AR 49644 AR 49647 Assay (%) NA 1.69
(0.01) 1.70 (0.00) 1.68 (0.01) % omega-IFN Purity 88.98 (0.09)
88.21 (0.03) 84.95 (0.58) 83.71 (0.48) % Oxidized 1.63 (0.04) 3.20
(0.03) 6.39 (0.05) 7.21 (0.10) % Deamidated 1.45 (0.01) 1.66 (0.01)
1.45 (0.40) 1.84 (0.03) % Unknown 7.94 (0.12) 6.93 (0.04) 7.22
(0.45) 7.24 (0.45) Analysis by SEC (n = 3)** Initial (t = 0) (AR
48217) Initial (t = 0)* 1 week 2 weeks (protein particles) AR 49640
AR 49644 AR 49647 % Monomer 99.93 (0.01) 99.83 (0.02) 99.75 (0.01)
99.51 (0.01) % Dimer 0.07 (0.01) 0.17 (0.02) 0.25 (0.01) 0.49
(0.01) Unknown ND ND ND ND ND = Not detected *n = 6 **standard
deviation in parenthesis
[0048] Stability of omega-interferon in untreated SAIB was again
tested. The results of a two week stability study (Study III) of
omega-interferon in SAIB (lot # TD 2032663) are comparable to
studies I and II. See Table 6, FIG. 4. The amount of oxidation was
found to have increased by 5.58%, while deamidation increased by
0.39% and dimerization increased by 0.42%.
Example 4
Study IV and V: Treatment of SAIB (Lot #TD2032663) with Basic
Alumina with Heating or with 10% Aqueous Methionine Solution
Treatment of SAIB with Basic Alumina with Heating
[0049] SAIB was heated to 90.degree. C. Basic alumina (15% w/w) was
added to the heated SAIB. Two different grades of alumina were
used--Basic Super I and Basic Standard Activity I. The resulting
mixture was stirred for 40 minutes. The mixture was then
centrifuged at 4000 rpm while temperature was maintained at
75.degree. C. After centrifugation, the supernatant was collected
and sampled for peroxide analysis.
Treatment of SAIB with 10% Aqueous Solution of Methionine
[0050] One part of SAIB was vigorously agitated with 4 parts of 10%
aqueous solution of methionine at 80.degree. C. for 45 minutes
using a magnetic stirrer. (Evaporated water was replenished as
necessary) Afterwards, the methionine solution was decanted. SAIB
was then washed with 4 parts of water by agitating for 15 minutes
at 70.degree.-80.degree. C. This washing step was carried out three
times. SAIB was placed overnight in vacuum oven at 70.degree. C. to
remove residual water, and, afterwards, was sampled for peroxide
analysis.
[0051] The peroxide content of SAIB treated with basic alumina or
with aqueous methionine solution was determined to be 109.3 and
95.7 respectively (Study IV and V), indicating that these
approaches were not successful in the removal of peroxides. See
FIG. 7.
Example 5
Study VIa and VIb: Stability of SAIB (Lot #TD2032663) Treated with
5% Aqueous Solution of Sodium Metabisulfite or Untreated for 8
Weeks
Treatment of SAIB with 5% Aqueous Solution of Sodium Metabisulfite
in Presence of Hexane
[0052] SAIB was dissolved in two parts of hexane. The resulting
solution was treated with a 5% aqueous solution of sodium
metabisulfite by vigorous shaking. The aqueous layer was removed
and the SAIB layer was washed with water. The SAIB layer was dried
with MgSO.sub.4. Hexane was removed from SAIB by evaporation under
vacuum at 50.degree. C. The treated SAIB was sampled for peroxide
analysis and used for preparation of suspension for stability
testing. TABLE-US-00007 TABLE 7 Stability of omega-interferon in
untreated SAIB and treated SAIB - Study VIa and VIb Stability of
omega-IFN in Untreated SAIB (Lot: TD 2032663) Analysis by RP-HPLC
(n = 3)** Initial (t = 0) Protein particles Initial (t = 0) 1 week
2 weeks 4 weeks 8 weeks AR 48219 AR 48445 AR48441 AR 48440 AR 50132
AR 50161 Assay (%) 11.45 (0.24) 1.00 (0.01) 1.00 (0.01) 1.00 (0.01)
0.94 (0.01) 0.94 (0.03) % omega-IFN 88.91 (0.39) 87.29 (0.25) 83.10
(0.08) 81.62 80.17 79.35 % Oxidized 1.90 (0.39) 3.38 (0.19) 7.86
(0.14) 8.54 (0.07) 8.94 (0.08) 8.86 (0.06) % Deamidated 2.02 (0.01)
2.15 (0.03) 2.24 (0.09) 2.59 (0.15) 3.33 (0.04) 4.46 (0.07) %
Unknown 7.17 (0.44) 7.18 (0.47) 6.80 (0.02) 7.25 (0.36) 7.55 (0.05)
7.33 (0.47) Analysis by SEC (n = 3)** Initial (t = 0) Protein
particles Initial (t = 0) 1 week 2 weeks 4 weeks 8 weeks AR 48219
AR 48445 AR48441 AR 48440 AR 50132 AR 50161 % Monomer 99.67 (0.01)
99.57 (0.02) 99.16 (0.01) 98.93 99.15 97.18 % Dimer 0.25 (0.01)
0.31 (0.02) 0.72 (0.01) 1.01 (0.04) 0.47 (0.05) 2.53 (0.13) Unknown
0.08 (0.00) 0.12 (0.01) 0.12 (0.00) 0.06 (0.00) 0.38 (0.02) 0.30
(0.05) Note: The omega content in the suspension was 1.00% and not
1.66% because the particles contained 11.45% omega and the loading
of particles in suspension was at 10% Stability of omega-IFN in
Treated SAIB (Lot: TD 2032663) Analysis by RP-HPLC (n = 3)**
Initial (t = 0) Protein particles Initial (t = 0) 1 week 2 weeks 4
weeks 8 weeks AR 48219 AR 48445 AR48441 AR 48440 AR 50132 AR 50161
Assay (%) 11.45 (0.24) 1.17 (0.01) 1.15 (0.00) 1.16 (0.00) 1.15
(0.00) 1.14 (0.01) % omega-IFN 88.91 (0.39) 88.11 (0.35) 86.25
(0.41) 85.83 85.41 84.52 % Oxidized 1.90 (0.39) 2.69 (0.17) 3.26
(0.07) 3.46 (0.09) 3.56 (0.05) 4.16 (0.11) % Deamidated 2.02 (0.01)
2.26 (0.04) 2.81 (0.01) 2.94 (0.04) 3.21 (0.06) 3.64 (0.06) %
Unknown 7.17 (0.44) 6.97 (0.39) 7.68 (0.37) 7.77 (0.38) 7.81 (0.45)
7.77 (0.55) Analysis by SEC (n = 3)** Initial (t = 0) Protein
particles Initial (t = 0) 1 week 2 weeks 4 weeks 8 weeks AR 48219
AR 48445 AR48441 AR 48440 AR 50132 AR 50161 % Monomer 99.67 (0.01)
99.59 (0.02) 99.34 (0.02) 99.41 99.42 99.00 % Dimer 0.25 (0.01)
0.35 (0.02) 0.53 (0.02) 0.54 (0.02) 0.29 (0.01) 0.94 (0.06) Unknown
0.08 (0.00) 0.05 (0.00) 0.13 (0.01) 0.05 (0.01) 0.29 (0.01) 0.06
(0.01) Note: The omega content in the suspension was 1.17% and not
1.66% because the particles contained 11.45% omega and the loading
of particles in suspension was at 10%. **standard deviation in
parenthesis
[0053] The stability study (Study VIa and VIb, Table 7, FIGS. 5-7)
conducted in treated (5% aqueous solution of sodium metabisulfite)
and untreated SAIB shows that oxidation levels are reduced at 8
weeks, along with the reduction of peroxide levels--4.16% in
treated SAIB versus 8.86% in untreated SAIB equivalent to a change
of 2.26% and 6.96%, respectively, from t=0 values of the protein
particles. (For all relative changes reported herein, the changes
are based on differences between the percentage values, e.g.,
percent oxidation, at t.sub.n and t=0 of the particles as opposed
to relative percent change from value at t=0). Deamidation
increased by 2.44% and 1.62% in untreated and treated SAIB,
respectively. Dimerization increased by 2.28% and 0.59% in
untreated and treated SAIB %, respectively. The quantities of
unknown did not change significantly over time, which indicates
that the extent of oxidation, deamidation and dimerization in
treated SAIB (low peroxide value of 2.6 ppm) was lower than in
untreated material. This treatment decreased the peroxide content
substantially. TABLE-US-00008 TABLE 8 Peroxide content of SAIB
Peroxide Study SAIB value AR # (Lot #) Treatment (ppm)* numbers I
TD1030507 Untreated 71.4 48557 IIa TD1030507 Treated with neutral
66.3 48568 alumina by heating IIb TD1030507 Treated with neutral
62.9 48568 alumina using ethanol III TD2032663 Untreated 115.9
48581 IV TD2032663 Treated with basic 109.3 48581 alumina by
heating V TD2032663 Treated with 10% aqueous 95.7 48446 solution of
methionine VIa TD2032663 Treated with hexane and 2.6 49648 sodium
metabisulfite VIb TD2032663 Untreated 115.9** 48581 *oxidative
activity equivalent to hydrogen peroxide (n = 1) **peroxide content
determined during Study III
[0054] As shown in FIG. 7, along with data provided in Table 8,
treatment with an aqueous solution of sodium metabisulfite was
effective in significantly reducing peroxide levels from 115.9 ppm
to 2.6 ppm--almost 45 times, or 45 fold decrease. In comparison,
treatment with neutral alumina, either with heat or with ethanol,
resulting in only a nominal change in peroxide levels--a 7% or 12%
decrease, respectively. In addition, treatment with basic alumina
with heat or 10% aqueous methionine only resulted in nominal change
in peroxide levels--a 6% or 18% decrease, respectively.
[0055] FIG. 8 illustrates an osmotically pump-driven implantable
device for delivering an SAIB formulation acting as a drug delivery
vehicle, active agent within. Depicted in FIG. 8 is an osmotically
pump-driven implantable device 10 shown comprising an impermeable
reservoir 12. The reservoir 12 is divided into two chambers by a
piston 16. The first chamber 18 is adapted to contain an SAIB
formulation 19 containing an active agent 20 and the second chamber
21 is adapted to contain a fluid-imbibing agent. A back-diffusion
regulating outlet 22 is inserted into the open end of the first
chamber 18 and a semipermeable membrane 24 encloses the open end of
the second chamber 21. The piston 16 is driven towards the open end
of the first chamber 18 by the osmotic pressure generated by the
fluid-imbibing agent in the second chamber 21. The pressure created
by the piston 16 can force the contents of the first chamber 18 out
the opening, i.e., the SAIB formulation 19 comprising active agents
20. The release rate of the active agent can be governed by the
osmotic pumping rate.
[0056] It is to be appreciated that certain features of the
invention which are, for clarity, described above in the context of
separate embodiments, may also be provided in combination in a
single embodiment. Conversely, various features of the invention
that are, for brevity, described in the context of a single
embodiment, may also be provided separately or in any
subcombination. Further, reference to values stated in ranges
includes each and every value within that range, unless clearly
expressed otherwise.
[0057] The entire disclosure of each patent, patent application,
and publication cited or described in this document is incorporated
herein by reference.
* * * * *