U.S. patent application number 13/871064 was filed with the patent office on 2013-09-12 for pharmaceutical microparticles.
This patent application is currently assigned to NOVARTIS AG. The applicant listed for this patent is Michael Ausborn, Olivier Lambert, Oskar Nagele. Invention is credited to Michael Ausborn, Olivier Lambert, Oskar Nagele.
Application Number | 20130236550 13/871064 |
Document ID | / |
Family ID | 27806083 |
Filed Date | 2013-09-12 |
United States Patent
Application |
20130236550 |
Kind Code |
A1 |
Ausborn; Michael ; et
al. |
September 12, 2013 |
PHARMACEUTICAL MICROPARTICLES
Abstract
Microparticles consisting of (a) a matrix with a mixture of
(a1)) at least one hydrophobic, biologically degradable polymer and
(a2) optionally at least one water-soluble polymer, (b) a
pharmaceutical active ingredient distributed in the matrix, and (c)
in addition at least one water-insoluble, surface-active substance
from the group of lecithins and phospholipids, distributed in the
matrix, and a three-phase emulsion process for their
preparation.
Inventors: |
Ausborn; Michael; (Lorrach,
DE) ; Lambert; Olivier; (Spechbach-le-Haut, FR)
; Nagele; Oskar; (Sissach, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ausborn; Michael
Lambert; Olivier
Nagele; Oskar |
Lorrach
Spechbach-le-Haut
Sissach |
|
DE
FR
CH |
|
|
Assignee: |
NOVARTIS AG
Basel
CH
|
Family ID: |
27806083 |
Appl. No.: |
13/871064 |
Filed: |
April 26, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13348114 |
Jan 11, 2012 |
8460709 |
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13871064 |
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12218639 |
Jul 17, 2008 |
8110224 |
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13348114 |
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10506822 |
Sep 7, 2004 |
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PCT/EP03/02565 |
Mar 12, 2003 |
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12218639 |
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Current U.S.
Class: |
424/489 ;
424/85.7 |
Current CPC
Class: |
A61P 43/00 20180101;
A61K 9/146 20130101; A61K 9/1617 20130101; A61K 9/1647 20130101;
A61K 9/1694 20130101 |
Class at
Publication: |
424/489 ;
424/85.7 |
International
Class: |
A61K 9/14 20060101
A61K009/14 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 13, 2002 |
DE |
10211040.9 |
Mar 27, 2002 |
DE |
10213856.7 |
Claims
1-15. (canceled)
16. A process for producing microparticles comprising the steps of:
a) dissolving at least one peptide, polypeptide, and/or protein in
an aqueous buffer to produce an active ingredient solution, b)
dissolving at least one biologically degradable polymer, at least
one water-soluble polymer, and lecithin in an organic solvent to
produce a polymer solution containing about 20% lecithin, c) mixing
the active ingredient solution of a) and the polymer solution of b)
using a gear pump to form an emulsion, d) pumping the emulsion of
c) and an aqueous solution with a gear pump to a static mixer and
mixing the same in the static mixer to form a water in oil in water
emulsion, e) removing the solvent from the emulsion of d), and f)
separating the microparticles, wherein the microparticles do not
exhibit an initial burst release of the therapeutic polypeptide
contained therein.
17. The method of claim 16 wherein the aqueous solution of c)
comprises an aqueous buffer and at least one surfactant and/or
water-soluble polymer.
18. The process of claim 16 further comprising circulating the
emulsion of d) through a membrane.
19. The process of claim 16 wherein the aqueous buffer is a
phosphate buffer.
20. The process of claim 16 wherein the organic solvent is
methylenechloride.
21. The process of claim 17 wherein the surfactant is polyvinyl
alcohol.
22. The process of claim 16 wherein the solvent is removed in e) by
vacuum and/or evaporation, optionally further comprising
heating.
23. The process of claim 16 wherein the amount of lecithin is from
0.01 to 90% w/w of the final microparticle weight.
24. The process of claim 16 wherein the biologically degradable
polymer is selected from the group consisting of a polycarbonate; a
polyester of an aliphatic hydroxycarboxylic acid; a polyester of an
aminocarboxylic acid; a polyamide of an aliphatic hydroxycarboxylic
acid; a polyamide of an aminocarboxylic acids; a homo-condensate of
.alpha.-hydroxycarboxylic acid; a copolycondensate of
.alpha.-hydroxycarboxylic acid; glycolic acid; lactic acid;
poly-L-lactic acid; poly-D,L-lactic acid; a copolycondensate of
poly-D,L-lactide/glycolide with a monomer ratio selected from the
group consisting of 10:1 to 1:10. 1:4 to 4:1, and 1:1, and a
molecular weight of 5000 to 100,000 daltons; and mixtures
thereof.
25. The process of claim 24 wherein the biologically degradable
polymer is a copolycondensate of D,L-lactic acid and glycolic acid
(1:1).
26. The process of claim 18 wherein the membrane is selected from
the group consisting of a polymer membrane, ceramic membrane,
hollow fiber, and spiral wound system.
27. A microparticle prepared by the process of claim 16.
28. The microparticle of claim 27 comprising an amount of lecithin
selected from the group consisting of about 0.01 to about 90%,
about 0.1 to about 70%, and about 0.1 to about 20% w/w.
29. The microparticle of claim 27 having a diameter of 0.1 to 200
.mu.m.
30. The microparticle of claim 27 comprising a biologically
degradable polymer comprising homo- or copolyester of dicarboxylic
acid, alkylene diol, polyalkylene glycol and/or aliphatic
hydroxycarboxylic acid; homo- or copolyamide of dicarboxylic acids,
alkylene diamine and/or aliphatic aminocarboxylic acid;
corresponding polyester-polyamide copolymer; polyanhydride;
polyorthoester; polyphosphazene; and polycarbonates.
31. The microparticle of claim 30, in which the biologically
degradable polymer is poly-L- or poly-D,L-lactic acid or
poly-D,L-lactide/glycolide with a monomer ratio of ca. 1:1 and a
molecular weight of 5000 to 100,000 daltons.
32. The microparticle of claim 27 comprising at least one
water-soluble polymer.
33. The microparticle of claim 32 wherein the water-soluble polymer
is polyvinyl pyrrolidone.
34. The microparticle of claim 29 in which the amount of
biologically degradable polymer is 1 to 99% by weight.
35. The microparticle of claim 27 wherein the at least one peptide,
polypeptide, and/or protein is selected from the group consisting
of an antibody, growth hormones, insulin, interferon,
erythropoietin, calcitonin, heparin, somatostatin, cell-stimulating
factors and parathyroid hormones.
36. The microparticle of claim 35 wherein the interferon is
interferon alpha 2b.
37. The microparticle of claim 26 wherein the amount of the at
least one peptide, polypeptide, and/or protein is about 1 to about
20% (w/w) of the microparticle.
Description
[0001] The invention relates to microparticles comprising at least
one biologically degradable polymer, optionally at least one water
soluble polymer and at least one pharmacologically active
ingredient distributed in the polymer containing a phospholipid or
lecithin and a process for their preparation.
[0002] Microparticles comprising a mixture of a biologically
degradable polymer and a water-soluble polymer, into which a
pharmaceutical active ingredient, preferably peptides, polypeptides
or proteins, are incorporated, are known from U.S. Pat. No.
5,869,103. It is mentioned that an undesired initial high release
of active ingredient, especially surface-active proteins, may be
suppressed it, during production of the particles, a stabiliser,
for example surfactants such as sorbitan monostearate or glyceryl
monostearate, is added to the organic phase of an active ingredient
emulsion or suspension. When active ingredient is released in
contact with a physiological medium, such surfactants are washed
out particularly quickly, so that the microparticle composition
changes. Therefore, these surface active agents will stay in the
polymer matrix for a very short period and will not prevent a
possible adsorption of the drug substance to the polymer matrix
during the release period. Therefore, a release of active
ingredient over a longer period is not achieved.
[0003] In Pharmaceutical Research, Vol. 14, No. 4, pages 420 to 425
(1997), J. L. Cleland describes the encapsulation of a recombinant
human growth hormone with a biologically degradable polymer, for
example a copolycondensate comprising lactic acid and glycolic
acid. In this system, the initial high release of active ingredient
can only be reduced, and the possible denaturing of the hormone is
avoided by adding trehalose or mannitol.
[0004] In Biotechnology and Bioengineering, Vol. 65, No. 6, pages
659 to 667 (1999), H. K. Tim et al describe that the encapsulation
of the recombinant human growth hormone in a copolycondensate
comprising lactic acid and glycolic acid leads to systems which
have a high initial release of hormone of up to over 50% and
afterwards no longer release any active ingredient. M. Morlock at
al. [European Journal of Pharmaceutics and Biopharmaceutics 43
(1997), pages 29-36] and B. Bittner at al. [European Journal of
Pharmaceutics and Biopharmaceutics 45 (1998), pages 295-305]
describe a similar behaviour when recombinant human erythropoietin
is encapsulated in a copolycondensate of lactic acid and glycolic
acid.
[0005] The problem of encapsulating pharmaceutical active
ingredients, especially surface-active peptides, polypeptides and
proteins in biologically degradable polymers, in order to attain a
constant release of active ingredient over a longer period of time
without a toss of activity in production and during storage and
administration, has not yet been solved in a satisfactory
manner.
[0006] It has now surprisingly been found that, using at least one
water insoluble surface active substance from the group of
lecithins and phospholipids together with the polymer for the
preparation of microparticles, high concentrations of
pharmacologically active ingredient in the area of the surface of
microparticles may be avoided. The continuous release may last at
least over a long period of time without observing a complete
breakdown of pharmacologically active ingredient into the
surrounding biological medium.
[0007] In one aspect the invention provides microparticles
comprising [0008] a) at least one biologically degradable polymer,
and [0009] b) optionally at least one water soluble polymer, and
[0010] c) at least one pharmacologically active ingredient
distributed in the polymer [0011] d) containing a phospholipids or
lecithin
[0012] The microparticles may have an irregular and preferably
essentially spherical shape. The particle diameter of the
individual microparticles may be 0.1 to 200 .mu.m, preferably 1 to
100 .mu.m, most preferably 1 to 50 .mu.m. Microparticles having an
average particle diameter in the range of 5 to 80 .mu.m, preferably
30 to 70 .mu.m, are preferred. The particle size may be controlled,
for example, by adjusting the process parameters and by selecting
solvents, polymers and the molecular weight of the polymers
employed.
[0013] Depending on the preparation process and the composition,
the microparticles may be compact and essentially pore-free
particles, or porous particles with a compact or porous
surface.
[0014] As used herein "biologically degradable polymers" means for
example those polymers that are decomposed in a physiological
medium. Hydrolytically degradable polymers are basically
appropriate for this.
[0015] Biologically degradable polymers are known and are, in part,
commercially obtainable. They may be, for example homo- or
copolyesters of dicarboxylic acids, alkylene diols, polyalkylene
glycols and/or aliphatic hydroxycarboxylic acids; homo- or
copolyamides of dicarboxylic acids, alkylene diamines, and/or
aliphatic aminocarboxylic acids; corresponding polyester-polyamide
copolymers, polyanhydrides, polyorthoesters, polyphosphazenes and
polycarbonates. Suitable dicarboxylic acids are, for example,
terephthalic acid and especially saturated aliphatic acids of
formula HOOC--(C.sub.nH.sub.2n)--COOH, wherein n is 0 or a number
from 1 to 6 (oxalic, malonic, succinic or adipic acid). Alkylene
diols may correspond for example to HO--(C.sub.xH.sub.2x)--OH,
wherein x is a number from 1 to 6 (ethane-, propane-, butane-,
pentane- or hexanediol). The hydroxycarboxylic acids may correspond
to formula HO--(C.sub.xH.sub.2x)--COOH, wherein x is a number from
1 to 6 (hydroxyacetic acid, hydroxypropionic acid, hydroxybutanoic
acid, hydroxypentanoic acid, hydroxyhexanoic acid). The
aminocarboxylic acids may correspond to formula
H.sub.2N--(C.sub.xH.sub.2x)--COOH, wherein x is a number from 1 to
6 (aminoacetic acid, aminopropionic acid, aminobutanoic acid,
arninopentanoic acid, aminohexanoic acid). The polyalkylene glycols
in question may be, for example, oligomers of ethylene glycol or
propylene glycol with ca. 2 to 100, preferably 2 to 50 monomer
units. Polycarbonates may contain recurring structural elements of
formula --CO--(C.sub.xH.sub.2x)--O--, wherein x is a number from 1
to 6. The molecular weight of the polymers may be, for example, 500
to 1,000,000, preferably 1000 to 500,000, most preferably 2000 to
100,000 daltons.
[0016] The biologically degradable polymers may be linear, branched
and optionally crosslinked. According to the invention, star
polymers may also be used, in which polymer chains are bonded to
the functional groups (for example hydroxyl, amino and/or carboxyl
groups) of a core monomer, such as saccharides. Such polymers are
known and are partly commercial.
[0017] Preferred biologically degradable polymers are selected from
the group of polycarbonates, and in particular the polyesters and
polyamides of aliphatic hydroxycarboxylic acids or aminocarboxylic
acids. Homo- and copolycondensates of .alpha.-hydroxycarboxylic
acids are especially preferred, for example glycolic acid and
lactic acid. The ratio of monomers in copolycondensates may be, for
example, 10:1 to 1:10, preferably 1:4 to 4:1. Especially preferred
polycondesates are poly-L- or poly-D,L-lactic acid. Preferred
copolycondensates are poly-D,L-lactide/glycolides with a monomer
ratio of ca. 1:1 and a molecular weight of 5000 to 100,000 daltons.
Mixtures of biologically degradable polymers may also be used. The
biologically degradable polymers are essentially insoluble in
water.
[0018] Water-soluble polymers are likewise known and available
commercially. They may be, for example, homo- or copolyoxa-alkylene
oxides of preferably ethylene and/or propylene glycol,
polyacrylamides and hydroxyalkylated polyacrylamides, polymaleic
acid and the partial esters or amides thereof, polyacrylic acid and
the partial esters or amides thereof, polyvinyl alcohol and the
partial esters or ethers thereof, polyvinyl imidazole, polyvinyl
pyrrolidone, and natural polymers, for example starch or chitosan.
Polyvinyl pyrrolidone is preferred. The water-soluble polymers may
have molecular weights of 1000 to 500,000, preferably 1000 to
100,000, most preferably 1000 to 20,000 daltons. Mixtures of
water-soluble polymers may also be used. The water-soluble polymers
should also be soluble in organic solvents.
[0019] The amount of biologically degradable polymers may be, for
example, 99 to 1% by weight, preferably 90 to 50% by weight, and
the amount of water-soluble polymers may be 1 to 99% by weight,
preferably 10 to 50% by weight, based on the composition of the
polymers.
[0020] The microparticles contain at least one water-insoluble
surfactant from the group of lecithins and phospholipids, the
addition of which ensures that the active ingredient is protected
against adsorption on the polymer matrix during the whole release
period. Due to this effect the invention provides microparticles
with extended release of an active ingredient. Lecithins and
phospholipids are known and are available commercially. These
surfactants may be extracted from natural products such as eggs or
soya. The lecithins in question are natural, partly hydrogenated
and hydrogenated lecithins or sphingolipids. Natural lecithins are
mixtures of different phospholipids. Examples of phospholipids are
phosphatidyl choline, phosphatidyl ethanolamine, lysophosphatidyl
choline, phosphatidyl glycerine, phosphatidic acid and phosphatidyl
serine, as well as the partially or fully hydrogenated derivatives
thereof. Examples of phospholipids with defined fatty acids are
1,2-dimyristoyl-sn-glycero-3-phosphocholine,
1,2-dipalmitoyl-sn-glycero-3-phosphocholine,
1,2-distearoyl-sn-glycero-3-phosphocholine,
1,2-dioleoyl-sn-glycero-3-phosphocholine,
1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine,
1,2-dimyristoyl-sn-glycero-3-phospho-rac-glycerine,
1,2-dipalmitoyl-sn-glycero-3-phospho-rac-glycerine and
1,2-distearoyl-sn-glycero-3-phospho-rac-glycerine. Lecithin and
phosphatidyl choline are preferably used.
[0021] The amount of lecithins and/or phospholipids may be 0.01 to
90% by weight, preferably 0.1 to 70% by weight, most preferably 0.1
to 20% by weight, based on the total composition of the
microparticles. The lecithins and phospholipids are essentially
uniformly distributed throughout the volume of the microparticles.
Insofar as the lecithins or phospholipids are only partly soluble
or insoluble in the solvent of the polymer solution, the formation
of a dispersion of these substances in the polymer solution may be
sufficient to achieve the effects according to the invention.
[0022] The pharmacologically active ingredients are in general
those that are stable under the preparation conditions.
Water-soluble active ingredients are preferred. Peptides,
polypeptides and proteins are preferred according to the invention,
especially those which adhere to the surface of microparticles
because of their surface-active properties and lead to the
formation of agglomerates. Further examples are carbohydrates,
oligonucleotides, RNA and DNA. A few examples of peptides,
polypeptides and proteins are antibodies, growth hormones, insulin,
interferons, erythropoietin, calcitonin, heparin, somatostatins,
cell-stimulating factors and parathyroid hormones. The aqueous
solutions may contain buffers and electrolytes, for example NaCl.
Examples of interferons are interferons of the alpha group,
preferably interferon alpha 2a or alpha 2b, most preferably
interferon alpha 2b.
[0023] The amount of active ingredient in the microparticles may be
0.1 to 90% by weight, preferably 1 to 70% by weight, most
preferably 1 to 20% by weight, based on the weight of the
microparticles.
[0024] Preparation processes for microparticles are known per se
and are described in relevant literature. According to the
invention, the water-insoluble and surface-active substances are
hereby added to the polymer solution, thereby providing optimum
protection of the pharmacologically active ingredients during
encapsulation and good distribution of the substance in the polymer
of the microparticles.
[0025] The particles may be produced, for example by dispersing
solid active ingredients um emulsifying liquid active ingredients
or active ingredient solutions in physiologically compatible
solvents in a polymer solution containing at least one
surface-active substance, and subsequently removing the solvent.
Evaporation may be undertaken at high agitation speeds in order to
form the particles. It is expedient to carry out spray-drying.
[0026] Microparticles may also be produced by precipitating the
polymer through the addition of a solvent, in which a polymer is
insoluble, at high agitation speeds, whereby the pharmacologically
active ingredient or the solution of an active ingredient is
embedded in the polymer of the formed microparticles.
[0027] In another aspect the invention provides a method of
producing microparticles by forming polymers from polymer
precursors (for example monomers and/or prepolymers) in a
dispersion or emulsion of an active ingredient or active ingredient
solution with the polymer precursors at high agitation speeds.
Dispersed or emulsified pharmacologically active ingredient is
hereby coated and precipitated by separating the polymer.
[0028] In a further aspect of the invention microparticles may be
formed by using encapsulation by means of polymer separation in
multi-phase systems of aqueous and organic media, which are
similarly known. For example, it is possible to emulsify aqueous
solutions, dispersions or emulsions of active ingredient in an
organic polymer solution, and then to emulsify this emulsion in
turn in water, in order to then form the microparticles by removing
the solvent. Furthermore, solutions, dispersions or emulsions of
active ingredient in an organic solvent can also be emulsified in
water, this emulsion is then emulsified in an organic polymer
solution, and afterwards the polymer is then precipitated by adding
a solvent which is immiscible with the polymer solution.
[0029] The water-insoluble and surface-active substances are hereby
added to the polymer solution, thereby providing optimum protection
for the active ingredients during encapsulation, with good
distribution of the substance in the polymer of the
microparticles.
[0030] Water-soluble pharmacologically active ingredients and in
particular water-soluble, optionally surface-active peptides,
polypeptides and proteins are preferably used as the aqueous
formulation for encapsulation, whereby it is particularly
advantageous to form the microparticles in a three-phase
system.
[0031] A further object of the invention is a process for the
preparation of microparticles, comprising the steps [0032] a)
preparation of an aqueous solution e.g. a phosphate buffer of at
least one pharmacologically active ingredient [0033] b) preparation
of a solution of a biodegradable polymer and optionally a water
soluble polymer as well as a surface active substance e.g. a
phospholipid or lecithin in an organic solvent which is insoluble
in water e.g. methylenechloride. [0034] c) mixing a surfactant e.g.
polyvinyl alcohol with phosphate buffer to form an aqueous solution
[0035] d) mixing solution a) and b) using a gear pump to form an
emulsion [0036] e) pumping emulsion d) and the aqueous solution c)
with a gear pump to a static mixer and mixing them in the static
mixer to form a water in oil in water emulsion [0037] f) removing
e.g. evaporating the solvent from emulsion e) [0038] g) separating
the microparticles by sedimentation (optionally by filtration) and
freeze-drying
[0039] Depending on the solubility of the pharmacologically active
ingredient and the desired dosaging thereof, the aqueous solution
of process step a) may contain 0.01 to 80%, preferably 0.1 to 60%,
most preferably 0.1 to 30% by weight of pharmacologically active
ingredient, based on the aqueous solution. The solution may contain
stabilising agents and/or water-soluble thickeners. If peptides,
polypeptides or proteins are used, it is expedient to add pH
buffers, e.g. phosphate buffers. In the case of peptides,
polypeptides or proteins, it is also advantageous to add protecting
agents, for example glycine or sugar. The components may be mixed
and dissolved by stirring, optionally whilst heating. Any insoluble
constituents can be filtered off before further use.
[0040] The polymers and the surface-active substance are
conveniently dissolved whilst stirring, optionally with heating.
Any insoluble constituents can be filtered off before further use.
The amount of biologically degradable polymer in the solution may
be. for example, 1 to 60%, preferably 0 to 50% by weight, the
amount of water-soluble polymer 0 to 50% by weight, and the amount
of surface-active substance 1 to 80%, preferably 2 to 40% by
weight, whereby the percentages by weight add up to 100%. Suitable
solvents, which are immiscible with water, are for example
hydrocarbons, halogenated hydrocarbons and ketones. Preferred
solvents are halogenated hydrocarbons, for example chloroform,
ethane trichloride or tetrachloride, and in particular methylene
dichloride.
[0041] In order to form an emulsion of the active ingredient
solution (a) in the solution of polymers and surface-active
substances (b), the solutions are mixed by agitating at high speed.
The volume ratio of solution a) to solution b) may be, for example,
from 1:1 to 1:50, preferably from 1:2 to 1:10. We have found out
that this emulsion forming step may be carried out in a
particularly advantageous manner by using a gear pump.
[0042] Gear pump technology is well known. Rotary gear pump may be
based on meshing gears. Gear pumps are positive displacement pumps
utilizing a set of gears as the displacement device. The fluid
pumps may have e.g. helical gears (angled teeth), spur gears
(straight teeth), or herringbone gears.
[0043] A typical gear pump includes at least two and sometimes at
least three gears including a drive gear and a driven gear housed
within a pumping chamber. Gear pumps are preferred by the present
applicants because of their quiet operation, hydraulic efficiency,
conjugate mechanical motion, constant sealing of the surfaces
between the mating gear flanks and the minimum entrapment of fluid
between the teeth that are in contact. The gear pump may have a
high load carrying capacity and run more smoothly.
[0044] The gear pump may be based on cavity technology. Such gear
pumps typically consist of a housing having an inlet, a liquid
conduit and an outlet. In the housing is a gear cavity, within
which gears meshingly engage and rotate. Liquid enters the gear
cavity near the engagement of the gears and on a side wherein the
gear teeth are disengaging. As liquid enters the gear cavity it is
entrained between the gear teeth and the walls of the gear cavity
and moved along the periphery of the gear cavity until it reaches
the point at which the gear teeth engage. This action sets up a
pressure differential between the liquid inlet and the liquid
outlet causing liquid flow.
[0045] Such gears intermesh with their teeth to produce high local
shear forces to form an emulsions. Gear pumps are preferred pumps
to create the shear stress in a closed chamber without creation of
air/liquid interfaces that are detrimental to the stability of
sensitive active ingredient as proteins and peptides.
[0046] Preferably a pump having a magnetic drive is used for
aseptic manufacture of microparticles. The pump head is coupled
with the driving pump and can be easily removed for sterilization.
A magnetic drive pump may have an outer annular magnet turned or
rotated by a motor. An annular inner magnet may be disposed within
the outer magnet and may be carried on a pump shaft. The inner
magnet may be isolated from the outer magnet by a thin metallic or
plastic cup. The inner magnet of such pumps may include a magnet
and flux ring assembly which operates in the liquid that is moved
through a system by the pump.
[0047] The gear pump may have suction shoes of the type shown in
U.S. Pat. No. 4,127,365 the edge of the shoe fitting within the
groove in each gear and bearing against the bottom of the groove.
The shoe may form a passageway from the liquid inlet duct in the
gear block (which is covered by the shoe) to the mesh point of the
gear teeth. The shoe may fit over the mesh point of the gears and
at least a span of two teeth to either side thereof, also fitting
over the inlet duct and thus isolating this area from the main pump
cavity to establish a small pump chamber within the pump cavity.
Since there is a pressure differential when the pump is operating
which is lower on the underside of the shoe than in the main pump
cavity, the shoe is held against the pump block. The shoe separates
the inlet duct from the discharge pressure, while accepting fluid
flow.
[0048] The technology of gear pumps using magnetic drives is
disclosed e.g. in U.S. Pat. Nos. 4,414,523 and 6,007,312. Gear
pumps are disclosed e.g. in U.S. Pat. Nos. 4,846,641, 4,414,523,
5,702,234, 5,908,067, 4,493,625, 6,007,312 and 6,033,193. The
contents of these patent specification are hereby incorporated by
reference.
[0049] Such pumps may be the Micropump Ismatex brand obtained e.g.
from Ismatec AG, Germany or Allschwil, Basel Switzerland. A typical
model is IP65
[0050] Typical flow rates may be e.g from about 1 ml/min to about
12000 ml/min e.g 300 ml/min Typical drive speeds may be e.g from
about 60 rpm to about 6000 rpm e.g 3000 rpm Typical differential
pressures may be e.g from about 0.1 to about 5.2 bar (75 psi).
[0051] The present invention provides the unforeseen use of gear
pumps to form emulsions. Using gear pumps emulsions may be formed
in an aseptic environment.
[0052] Emulsion (d) is subsequently mixed with water (c) whilst
stirring at high speed to form a water in oil in water emulsion.
The water may contain stabilisers, for example polyvinyl alcohol or
gelatin and buffers. The amount of stabilisers may be 0.01 to 20%,
preferably 0.01 to 10% by weight, based on the aqueous solution of
the stabiliser. Advantageously this emulsion step is carried out
using a static mixer.
[0053] Using a static mixer, e.g a static laminar mixing device
homogenization may be effected by the flow through the mixer.
Generally, these devices have been built up of the so-called static
mixer elements. These elements may be present to upset the flow of
the liquids and mix them. Shear forces may be determinated by the
number and type of mixing elements and by the flow of liquids
through the static mixer.
[0054] Such laminar mixers may be employed in mixing devices for
the mixing of low-viscosity soluble additives to high-viscosity
liquids. During mixing, the lower-viscosity (limpid) liquid may be
fed to the main flow of the higher-viscosity (viscid) liquid, e.g.,
via a tube which may be arranged before or directly at the inlet to
the mixer.
[0055] We have found that using a static mixer emulsions and
microparticles having a controlled, predictable, and narrow cell
size distribution may be obtained.
[0056] Energy required for liquid flow may be produced by pumps or
the like.
[0057] A typical mixer is Sulzer Mixer SMXS DN6 obtainable from
Sulzer AG, Winterthur, Switzerland.
[0058] Typical flow rates of the first liquid (e.g. the internal
phase) containing the organic solvent may be e.g from about 1
ml/min to about 12000 ml/min e.g 20 ml/min.
[0059] Typical flow rates of the second liquid (e.g. the continuous
phase) containing water may be e.g from about 1 ml/min to about
12000 ml/min e.g 400 ml/min
[0060] Typical pressure drops may be e.g from about 0.1 to about
5.2 bar (75 psi)
[0061] Process steps b) to f) are preferably carried out at room
temperature.
[0062] Removal of the organic solvent is advantageously undertaken
with further stirring and by applying a vacuum. Heating can mean a
temperature of up to ca. 60.degree. C.
[0063] The microparticles may optionally be washed to purify them
(to remove organic solvent and surfactants such as polyvinyl
alcohol or gelatin) and then isolated by sedimentation or
optionally by filtration and dried to remove water and any residual
solvents. The known freeze-drying process is an especially suitable
process for this.
[0064] Process step f) may be replaced by cross-flow filtration.
Cross-flow filtration affords the circulation of the microparticle
suspension tangentially to a membrane e.g. a polymer membrane
(Polyethersulfone Pall membrane type Omega), e.g. a ceramic
membrane, e.g. hollow fibers or e.g. spiral wound systems. The pore
size of these membranes may be from 0.1 to 1 micrometer, preferably
0.8 micrometer for microfiltration. For ultrafiltration, membranes
with molecular weight cut off ranging from 100 to 1,000,000 daltons
are used. The suspension is recirculated until organic solvents and
surfactants as e.g. polyvinyl alcohol or e.g. gelatin are removed.
Microparticles may collected by sedimentation or by filtration.
[0065] We have found that microparticles therefrom having a
controlled, predictable, and narrow cell size distribution may be
obtained.
[0066] Typical flow rates tangentially over the membrane are e.g.
from about 1 ml/min to about 100, 000 ml/min e.g. 15,000 ml/min
[0067] Typical pressure drops may be e.g. from about 0.01 to about
5 bars.
[0068] After drying, microparticles are obtained in the form of
free-flowing powders, which can be easily handled and further
processed. The microparticles are essentially free from
agglomerates.
[0069] Microparticles may be resuspended in an aqueous solution
containing a bulking agent (e.g. mannitol or sucrose). This
suspension may be freeze-dried to get lyophilized microparticles
with advantageous storage properties.
[0070] The structure of the microparticles depends mainly on the
preparation process, the consistency of the active ingredients or
their solutions, and the choice of polymers or polymer
mixtures.
[0071] Encapsulation of solid active ingredients and of active
ingredients dispersed in polymer solutions leads to essentially
compact particles with little to no porosity. Release of the active
ingredient in contact with a physiological medium is determined in
the case of such particles by the decomposition of the polymer.
Release can be accelerated by adding water-soluble polymers, since
porous structures can be formed through the dissolving of
water-soluble polymers. The surface-active substance then protects
the active ingredient, so that a delayed release of active
ingredient remains assured.
[0072] Using the water in oil in water process, an aqueous solution
containing the active ingredient is emulsified in the polymer
solution. After drying, the water contained in droplets of this
primary emulsion are removed and the previous droplets form then
cavities in the dried polymer matrix. The cavities are distributed
randomly throughout the volume. The size of the cavities
distributed throughout the volume depends on the particle size, the
process parameters, the selected polymers, their quantitative
composition, and the type and amount of surface-active substance.
The diameter of the cavities may be, for example, from 0.01 to 100
.mu.m, depending on the size of the microparticles. The cavities
are partially or wholly filled with an aqueous, solution of at
least one pharmacologically active ingredient. The microparticles
may have pores in the surface area, especially if water-soluble
polymers are used concurrently during preparation, or if solutions,
emulsions and dispersions of active ingredient are not fully
encapsulated in the surface area.
[0073] The microparticles according to the invention are notable
for the delayed release behaviour of the pharmaceutical active
ingredient in a physiological medium. An initially excessive
release (also called initial burst) and a subsequent complete
breakdown of the release of active ingredient is not observed, even
if surface-active peptides, polypeptides or proteins are used. The
delayed release of active ingredient in, for example, blood plasma,
can be maintained until the pharmacologically active ingredient in
the particles has been used up, which can last for several days up
to 12 months, depending on the amount and especially on the polymer
used. In a first and second stage, the release of active ingredient
may be essentially constant, whereby in the first stage a higher
amount, for example 10 to 70% of the total amount of active
ingredient, is delivered in a shorter space of time. With the type
of composition and the amount of active ingredient in the
particles, an optimum dosage can be set, which will suffice for
long-term action with single or multiple administration. Using for
example the starpolymer poly-D,L-lactide/glycolide the release of
an active ingredient may last from several days up to 8 weeks.
Using the starpolymer poly-D,L-lactide/glycolide together with
interferon alpha 2b the invention provides a favourable release
profile over at least 21 days. 10% to 60% of the active ingredient
are released in the 2 to 5 days and the remaining active ingredient
over a period of at least 21 days.
[0074] If the microparticles do not contain lecithin or
phospholipid in the biologically degradable polymer, then in
contrast to the particles according to the invention, no active
ingredient is delivered after the initial burst phase. If a
water-soluble polymer is additionally incorporated in the polymer
matrix consisting of biologically degradable polymer and lecithin
or phospholipid, then the active substance is released faster due
to the creation of additional pores in the polymer matrix. The
release period is then shortened and the release process is then
essentially based on diffusion and not on a combination of
diffusion and polymer degradation.
[0075] The microparticles according to the invention are suitable
for formulating in solid, pasty and liquid formulations for oral
application (tablet, coated tablet, capsule, drinking solution or
suspension), for parenteral application (syringes for intravenous
or intramuscular administration, infusion with suspensions),
suppositories for rectal or vaginal application, aerosols for
application by inhalation, powders, creams, gels and transdermal
systems for subcutaneous application, and drops for nasal or
ophthalmic application.
[0076] Following is a non-limiting description by way of
example.
A) PREPARATION EXAMPLES
Example A1
Preparation of Microparticles
[0077] a) Preparation of the active ingredient solution
[0078] 216.36 mg of recombinant human interferon alpha-2b and 43.27
mg of glycine are dissolved in 3 ml of a phosphate buffer (pH 7.5,
25 mM potassium and sodium hydrogen phosphates, 130 mM NaCl, 0.3 mM
ethylenediamine tetraacetic acid).
[0079] b) Preparation of the polymer solution
[0080] 2561.5 mg of copolycondensate of D,L-lactic acid and
glycolic acid (50:50), 640.4 mg of polyvinyl pyrrolidone (PVP K12)
and 865.4 mg of lecithin (Epikuron.RTM. 200) are dissolved in 20 ml
of methylene chloride.
[0081] c) Preparation of the aqueous phase
[0082] 40 g of polyvinyl alcohol (PVA Mowiol.RTM. 18-88) in
phosphate buffer ( 1/15 M, pH 7.4, 7.24 g KH.sub.2PO.sub.4 and
30.28 g Na.sub.2HPO.sub.4) are dissolved in 4 litres of water at
20.degree. C.
[0083] d) Preparation of the primary emulsion
[0084] Solutions a) and b) are emulsified for 10 minutes using a
gear pump (Ismatec.RTM. MCP-Z, pump head P1830) at 200 rpm and at a
pump capacity of 270 ml per minute.
[0085] e) Preparation of microparticles
[0086] The primary emulsion is pumped by a gear pump (Ismatec.RTM.
MCP-Z, pump head P1830) at 200 rpm and at a pump capacity of 20 ml
per minute, and the aqueous phase is pumped by a gear pump
(Ismatec.RTM. MCP-Z, pump head P130) at 575 rpm and at a pump
capacity of 400 ml per minute in a mixing vessel
(Statischemischer.RTM. SMXS DN6)
[0087] f) Methylene chloride is evaporated whilst stirring.
[0088] g) The microparticles are filtered off, dried in a vacuum,
and the pre-dried microparticles undergo freeze-drying. A
free-flowing powder consisting of microparticles with an average
diameter of 60-70 .mu.m is obtained.
Example A2
Preparation of Microparticles
[0089] The procedure of example A1 is followed using the following
solutions:
[0090] a) Preparation of the active ingredient solution
[0091] 216.36 mg of recombinant human interferon alpha-2b and 43.27
mg of glycine are dissolved in 2 ml of a phosphate buffer (pH 7.5,
25 mM potassium and sodium hydrogen phosphates, 130 mM NaCl, 0.3 mM
ethylenediamine tetraacetic acid).
[0092] b) Preparation of the polymer solution
[0093] 2134.6 mg of copolycondensate of DA-lactic acid and glycolic
acid (50:50), 1067.3 mg of polyvinyl pyrrolidone (PVP K12) and
865.4 mg of lecithin (Epikuron.RTM. 200) are dissolved in 20 ml of
methylene chloride.
[0094] c) Preparation of the aqueous phase
[0095] 40 g of polyvinyl alcohol (PVA Mowiol.RTM. 18-88) in
phosphate buffer ( 1/15 M, pH 7.4, 7.24 g KH.sub.2PO.sub.4 and
30.28 g Na.sub.2HPO.sub.4) are dissolved in 4 litres of water at
20.degree. C.
[0096] Steps d to g are carried out as described in example A1.
[0097] A free-flowing powder consisting of microparticles with an
average diameter of 60-70 .mu.m is obtained.
Example A3
Preparation of Microparticles
[0098] The procedure of example A1 is followed using the following
solutions:
[0099] a) Preparation of the active ingredient solution
[0100] 50.6 mg of recombinant human interferon alpha-2b and 10.12
mg of glycine are dissolved in 3 ml of a phosphate buffer (pH 7.5,
25 mM potassium and sodium hydrogen phosphates, 130 mM NaCl, 0.3 mM
ethylenediamine tetraacetic acid).
[0101] b) Preparation of the polymer solution
[0102] 2000 mg of copolycondensate of D,L-lactic acid and glycolic
acid (50:50), 2000 mg of polyvinyl pyrrolidone (PVP K12) and 1000
mg of lecithin (Epikuron.RTM. 200) are dissolved in 20 ml of
methylene chloride.
[0103] c) Preparation of the aqueous phase
[0104] 40 g of polyvinyl alcohol (PVA Mowiol.RTM. 18-88) in
phosphate buffer ( 1/15 M, pH 7.4, 7.24 g KH.sub.2PO.sub.4 and
30.28 g Na.sub.2HPO.sub.4) are dissolved in 4 litres of water at
20.degree. C. Steps d to g are carried out as described in example
A1.
[0105] A free-flowing powder consisting of microparticles with an
average diameter of 60-70 .mu.m is obtained.
Example A4
Preparation of Microparticles: Adjustment of the Osmolarity of the
Aqueous Outer Phase
[0106] a) Preparation of the active ingredient solution
[0107] 216.36 mg of recombinant human interferon alpha-2b and 43.27
mg of glycine are dissolved in 3 ml of a phosphate buffer (pH 7.5,
25 mM potassium and sodium hydrogen phosphates, 130 mM NaCl, 0.3 mM
ethylenediamine tetraacetic acid).
[0108] b) Preparation of the polymer solution
[0109] 2561.5 mg of copolycondensate of D,L-lactic acid and
glycolic acid (50:50), 640.4 mg of polyvinyl pyrrolidone (PVP K12)
and 865.4 mg of lecithin (Epikuron.RTM. 200) are dissolved in 20 ml
of methylene chloride.
[0110] c) Preparation of the aqueous phase
[0111] 40 g of polyvinyl alcohol (PVA Mowiol.RTM. 18-88) in
phosphate buffer ( 1/15 M, pH 7:4, 7.24 g KH.sub.2PO.sub.4 and
30.28 g Na.sub.2HPO.sub.4) are dissolved in 4 litres of water at
20.degree. C. The osmolarity of the solution is then adjusted with
mannitol to the osmolarity of the protein aqueous solution a) at
about 600 mOsm.
[0112] d) Preparation of the primary emulsion
[0113] Solutions a) and b) are emulsified for 10 minutes using a
gear pump (Ismatec.RTM. MCP-Z, pump head P1830) at 200 rpm and at a
pump capacity of 270 ml per minute.
[0114] e) Preparation of microparticles
[0115] The primary emulsion is pumped by a gear pump (Ismatec.RTM.
MCP-Z, pump head P1830) at 200 rpm and at a pump capacity of 20 ml
per minute, and the aqueous phase is pumped by a gear pump
(Ismatec.RTM. MCP-Z, pump head P130) at 575 rpm and at a pump
capacity of 400 ml per minute in a mixing vessel
(Statischemischer.RTM. SMXS DN6).
[0116] f) Methylene chloride is evaporated whilst stirring.
[0117] g) The microparticles are washed by using different cycle of
sedimentation/soak-up of supernatant/addition of fresh water
(filtration and washing on the filter could be an alternative), the
washed microparticles can be freeze dried as a suspension or as
powder after filtration. A free-flowing powder consisting of
microparticles with an average diameter of 60-70 .mu.m is obtained.
For washing and freeze-drying the microparticles are suspended in
the buffered solution and filled in vials as suspension prior to
lyophilization. The buffered solution is the solution used for the
aqueous solution c) is used without the polyvinylalcohol or any
other surface active agents:
[0118] A phosphate buffer ( 1/15 M, pH 7.4, 7.24 g KH.sub.2PO.sub.4
and 30.28 g Na.sub.2HPO.sub.4) is prepared in 4 litres of water at
20.degree. C. The osmolarity of the solution is then adjusted with
mannitol to the osmolarity of the protein aqueous solution a) at
about 600 mOsm.
Example A5
Preparation of Microparticles: Use of the Cross-flow Filtration
Technology to Wash the Microparticles Suspension
[0119] a) Preparation of the active ingredient solution
[0120] 216.36 mg of recombinant human interferon alpha-2b and 43.27
mg of glycine are dissolved in 3 ml of a phosphate buffer (pH 7.5,
25 mM potassium and sodium hydrogen phosphates, 130 mM NaCl, 0.3 mM
ethylenediamine tetraacetic acid).
[0121] b) Preparation of the polymer solution
[0122] 2561.5 mg of copolycondensate of D,L-lactic acid and
glycolic acid (50:50), 640.4 mg of polyvinyl pyrrolidone (PVP K12)
and 865.4 mg of lecithin (Epikuron.RTM. 200) are dissolved in 20 ml
of methylene chloride.
[0123] c) Preparation of the aqueous phase
[0124] 40 g of polyvinyl alcohol (PVA Mowiol.RTM. 18-88) in
phosphate buffer ( 1/15 M, pH 7.4, 7.24 g KH.sub.2PO.sub.4 and
30.28 g Na.sub.2HPO.sub.4) are dissolved in 4 litres of water at
20.degree. C.
[0125] d) Preparation of the primary emulsion
[0126] Solutions a) and b) are emulsified for 10 minutes using a
gear pump (Ismatec.RTM. MCP-Z, pump head P1830) at 200 rpm and at a
pump capacity of 270 ml per minute.
[0127] e) Preparation of microparticles
[0128] The primary emulsion is pumped by a gear pump (Ismatec.RTM.
MCP-Z, pump head P1830) at 200 rpm and at a pump capacity of 20 ml
per minute, and the aqueous phase is pumped by a gear pump
(Ismatec.RTM. MCP-Z, pump head P130) at 575 rpm and at a pump
capacity of 400 ml per minute in a mixing vessel
(Statischemischer.RTM. SMXS DN6).
[0129] f) The whole microparticle suspension recovered in a tank is
then washed by mean of the cross-flow filtration technology to
remove methylenechloride and all the salts and excipients contained
in the aqueous outer phase c): the microparticle suspension is
pumped in a loop and allowed to circulate tangentially to a polymer
membrane with a pore size of 0.8 micrometer e.g. polyethersulfone
with low binding properties or e.g. ceramic membranes. The
methylenechloride, salts and excipients are removed through the
membrane by mean of the diafiltration mode of the cross-flow
filtration. They are filtered and removed as permeat whereas the
microparticles that cannot pass through the membrane stay in
suspension and come back in the loop as retentat. The water
containing methylenechloride, salts and excipients as PVA that is
removed with the permeat is replaced continuously by fresh water in
order to keep the volume of the initial microparticles suspension
at a constant level
[0130] g) Microparticles are filtered off, dried in a vacuum, and
the pre-dried microparticles undergo freeze-drying. The
microparticles suspension can as well be concentrated and fill in
vial as suspension prior to freeze-drying. A free-flowing powder
consisting of microparticles with an average diameter of 60-70
.mu.m is obtained.
B) APPLICATION EXAMPLES
Example B1
In Vitro Drug Release
[0131] 50 mg of the microparticles according to example A1 are
added to a phosphate buffer (pH 7.4, 1/15 M, pH 7.4. 724 g
KH.sub.2PO.sub.4 and 30.28 g Na.sub.2HPO.sub.4) and the mixture is
maintained at 37.degree. C. Then, at certain intervals, the
interferon alpha-2b content in the phosphate buffer is determined.
The results are listed in table 1.
TABLE-US-00001 TABLE 1 content in the cumulative content time
(days) buffer (mg) in the buffer (mg) 1 0.75995 0.75995 2 0.43124
1.19119 3 0.28770 1.47889 6 0.34728 1.82617 8 0.19125 2.01742 10
0.13053 2.14795 14 0.11585 2.26380 17 0.07464 2.33844 21 0.06015
2.39859
Example B2
[0132] The process is carried out according to example B1 with the
microparticles according to example A2. The results are listed in
table 2.
TABLE-US-00002 TABLE 2 content in the cumulative content time
(days) buffer (mg) in the buffer (mg) 1 1.03206 1.03206 2 0.45725
1.48931 3 0.19730 1.68661 6 0.17711 1.86372 8 0.13755 2.00147 10
0.11351 2.11498 14 0.15434 2.26932 17 0.09404 2.36336 21 0.06710
2.430046
* * * * *