U.S. patent application number 17/748933 was filed with the patent office on 2022-09-08 for compositions of bupivacaine multivesicular liposomes.
The applicant listed for this patent is Pacira Pharmaceuticals, Inc.. Invention is credited to Soroush M. Ardekani, John J. Grigsby, JR., Jeffrey S. Hall, Kathleen D. A. Los, David J. Turnbull.
Application Number | 20220280426 17/748933 |
Document ID | / |
Family ID | 1000006351431 |
Filed Date | 2022-09-08 |
United States Patent
Application |
20220280426 |
Kind Code |
A1 |
Hall; Jeffrey S. ; et
al. |
September 8, 2022 |
COMPOSITIONS OF BUPIVACAINE MULTIVESICULAR LIPOSOMES
Abstract
Embodiments of the present application relate to compositions of
multivesicular liposomes (MVLs) and manufacturing processes for
making bupivacaine MVLs.
Inventors: |
Hall; Jeffrey S.; (San
Diego, CA) ; Turnbull; David J.; (San Diego, CA)
; Grigsby, JR.; John J.; (San Diego, CA) ;
Ardekani; Soroush M.; (San Diego, CA) ; Los; Kathleen
D. A.; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pacira Pharmaceuticals, Inc. |
San Diego |
CA |
US |
|
|
Family ID: |
1000006351431 |
Appl. No.: |
17/748933 |
Filed: |
May 19, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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17590636 |
Feb 1, 2022 |
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17748933 |
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17156424 |
Jan 22, 2021 |
11278494 |
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17590636 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 47/28 20130101;
A61K 47/183 20130101; A61K 31/445 20130101; A61K 47/12 20130101;
A61K 9/127 20130101; A61K 47/14 20130101 |
International
Class: |
A61K 9/127 20060101
A61K009/127; A61K 47/14 20060101 A61K047/14; A61K 31/445 20060101
A61K031/445; A61K 47/18 20060101 A61K047/18; A61K 47/12 20060101
A61K047/12; A61K 47/28 20060101 A61K047/28 |
Claims
1. Batches comprising compositions of bupivacaine multivesicular
liposomes (MVLs), comprising: bupivacaine residing inside a
plurality of internal aqueous chambers of the MVLs separated by
lipid membranes, wherein the lipid membranes comprise
1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; and an aqueous medium in which the
bupivacaine encapsulated MVLs are suspended; wherein the rate of
hydrolysis of DEPC as measured by an erucic acid concentration is
less than about 18.75 .mu.g/mL/month after the compositions are
stored at 25.degree. C. for six months.
2. The batches of claim 1, wherein the rate of hydrolysis of DEPC
as measured by the erucic acid concentration is about 15.31
.mu.g/mL/month after the compositions are stored at 25.degree. C.
for six months.
3. The batches of claim 1, wherein the compositions have an initial
pH of about 7.0 to about 7.4.
4. The batches of claim 1, the compositions have a pH of about 6.5
after the compositions are stored at 25.degree. C. for six
months.
5. The batches of claim 1, wherein the at least one neutral lipid
of the lipid membranes comprises tricaprylin.
6. The batches of claim 1, wherein the lipid membranes further
comprise cholesterol.
7. The batches of claim 1, wherein the bupivacaine concentration in
the compositions is from about 11.3 mg/mL to about 17.0 mg/mL.
8. The batches of claim 7, wherein the bupivacaine concentration in
the compositions is about 13.3 mg/mL.
9. The batches of claim 1, wherein the compositions comprise less
than 5% by weight unencapsulated bupivacaine.
10. The batches of claim 1, wherein the d.sub.50 of the MVLs in the
compositions is about 24 .mu.m to about 31 .mu.m.
11. The batches of claim 1, wherein the percent packed particle
volume (% PPV) of the bupivacaine encapsulated MVLs in the
compositions is about 35% to 40%.
12. The batches of claim 1, wherein the internal aqueous chambers
of the MVLs comprises lysine, and the encapsulated lysine
concentration in the bupivacaine encapsulated MVLs compositions is
about 0.03 mg/mL.
13. The batches of claim 1, wherein the DEPC and DPPG in the
compositions are in a mass ratio of about 7:1 to about 10:1.
14. The batches of claim 1, wherein the bupivacaine is in a salt
form.
15. The batches of claim 14, wherein the bupivacaine is in the form
of bupivacaine phosphate.
16. The batches of claim 1, wherein the aqueous medium comprises a
saline solution.
17. A method of treating or ameliorating pain in a subject in need
thereof, comprising administering a bupivacaine multivesicular
liposomes composition of claim 1 to the subject.
18. The method of claim 17, wherein the administration is via local
infiltration to a surgical site to provide postsurgical local
analgesia.
19. The method of claim 17, wherein the administration is via
interscalene brachial plexus nerve block or femoral nerve block to
provide postsurgical regional analgesia.
20. The method of claim 17, wherein the composition has a volume of
10 mL or 20 mL for a single-dose administration.
21. The method of claim 17, wherein the composition has an initial
pH of about 7.0 to about 7.4.
22. The method of claim 17, wherein the composition has a pH of
about 6.5 after the composition is stored at 25.degree. C. for six
months.
23. The method of claim 17, wherein the at least one neutral lipid
of the lipid membranes comprises tricaprylin.
24. The method of claim 17, wherein the lipid membranes further
comprise cholesterol.
25. The method of claim 17, wherein the bupivacaine concentration
in the composition is from about 11.3 mg/mL to about 17.0
mg/mL.
26. The method of claim 25, wherein the bupivacaine concentration
in the composition is about 13.3 mg/mL.
27. The method of claim 17, wherein the composition comprises less
than 5% by weight unencapsulated bupivacaine.
28. The method of claim 17, wherein the d.sub.50 of the
multivesicular liposomes in the composition is about 24 .mu.m to
about 31 .mu.m.
29. The method of claim 17, wherein the percent packed particle
volume (% PPV) of the bupivacaine encapsulated multivesicular
liposomes in the composition is about 35% to 40%.
30. The method of claim 17, wherein the internal aqueous chambers
of the MVLs comprises lysine, and the encapsulated lysine
concentration in the bupivacaine encapsulated MVLs composition is
about 0.03 mg/mL.
Description
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 17/590,636, filed Feb. 1, 2022, which is a
continuation of U.S. application Ser. No. 17/156,424, filed Jan.
22, 2021, now U.S. Pat. No. 11,278,494, each of which is
incorporated by reference in its entirety.
BACKGROUND
Field
[0002] This disclosure relates generally to commercial
manufacturing processes for making multivesicular liposomes using
independently operating tangential flow filtration systems.
Description of the Related Art
[0003] Bupivacaine is a versatile drug that has been shown to be
efficacious for a wide variety of indications, including: local
infiltration, peripheral nerve block, sympathetic nerve block, and
epidural and caudal blocks. It may be used in pre-, intra- and
post-operative care settings. Bupivacaine encapsulated
multivesicular liposomes (Exparel.RTM.) has been approved in the US
and Europe for use as postsurgical local analgesia and as an
interscalene brachial plexus nerve block to produce postsurgical
regional analgesia, providing significant long-lasting pain
management across various surgical procedures. Particularly,
Exparel.RTM. has had great success in the market in part due to the
ability to locally administer bupivacaine multivesicular liposomes
(MVLs) at the time of surgery and extend the analgesic effects
relative to other non-liposomal formulations of bupivacaine. Such
extended release properties of bupivacaine MVLs allow patients to
control their post-operative pain without or with decreased use of
opioids. Given the addictive nature of opioids and the opioid
epidemic that has been affecting countries around the world, there
is an urgent need for new and improved large scale productions of
Exparel.RTM. to meet the substantial and growing market demand.
SUMMARY
[0004] Some aspects of the present disclosure relate to a crossflow
filtration system comprising: [0005] a diafiltration vessel; and
[0006] a plurality of independently operating crossflow modules,
each crossflow module of the plurality of independently operating
crossflow modules comprising at least one filter array, each filter
array comprising a plurality of hollow fiber filters, wherein each
crossflow module of the plurality of independently operating
crossflow modules is connected to a retentate conduit, a permeate
conduit, and a rotary lobe pump. In some embodiments, the crossflow
filtration system may be used in the microfiltration and/or
diafiltration step of the commercial process described herein.
[0007] Some aspects of the present disclosure relate to a process
for preparing bupivacaine encapsulated multivesicular liposomes in
a commercial scale, the process comprising: [0008] (a) mixing a
first aqueous solution comprising phosphoric acid with a volatile
water-immiscible solvent solution to form a water-in-oil first
emulsion, wherein the volatile water-immiscible solvent solution
comprises bupivacaine, at least one amphipathic lipid and at least
one neutral lipid; [0009] (b) mixing the water-in-oil first
emulsion with a second aqueous solution to form a
water-in-oil-in-water second emulsion; [0010] (c) removing the
volatile water-immiscible solvent from the water-in-oil-in-water
second emulsion to form a first aqueous suspension of bupivacaine
encapsulated multivesicular liposomes having a first volume; [0011]
(d) reducing the first volume of the first aqueous suspension of
bupivacaine encapsulated multivesicular liposomes by
microfiltration to provide a second aqueous suspension of
bupivacaine encapsulated multivesicular liposomes having a second
volume; [0012] (e) exchanging the aqueous supernatant of the second
aqueous suspension with a saline solution by diafiltration to
provide a third aqueous suspension of bupivacaine encapsulated
multivesicular liposomes having a third volume; and [0013] (f)
further reducing the third volume of the third aqueous suspension
by microfiltration to provide a final aqueous suspension of
bupivacaine encapsulated multivesicular liposomes having a target
concentration of bupivacaine; [0014] wherein all steps are carried
out under aseptic conditions.
[0015] Some aspects of the present disclosure relate to a
composition of bupivacaine encapsulated multivesicular liposomes
(MVLs) prepared by a commercial scale process, the commercial scale
process comprising: [0016] (a) mixing a first aqueous solution
comprising phosphoric acid with a volatile water-immiscible solvent
solution to form a water-in-oil first emulsion, wherein the
volatile water-immiscible solvent solution comprises bupivacaine,
1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; [0017] (b) mixing the water-in-oil
first emulsion with a second aqueous solution to form a
water-in-oil-in-water second emulsion; [0018] (c) removing the
volatile water-immiscible solvent from the water-in-oil-in-water
second emulsion to form a first aqueous suspension of bupivacaine
encapsulated MVLs having a first volume; [0019] (d) reducing the
first volume of the first aqueous suspension of bupivacaine
encapsulated MVLs by microfiltration to provide a second aqueous
suspension of bupivacaine encapsulated MVLs having a second volume;
[0020] (e) exchanging the aqueous supernatant of the second aqueous
suspension with a saline solution by diafiltration to provide a
third aqueous suspension of bupivacaine encapsulated MVLs having a
third volume; and [0021] (f) further reducing the third volume of
the third aqueous suspension by microfiltration to provide a final
aqueous suspension of bupivacaine encapsulated MVLs having a target
concentration of bupivacaine; [0022] wherein all steps are carried
out under aseptic conditions; and [0023] wherein the erucic acid
concentration in the composition is about 23 .mu.g/mL or less after
the composition is stored at 25.degree. C. for one month.
[0024] Some aspect of the present disclosure relates to a
composition of bupivacaine encapsulated multivesicular liposomes
(MVLs), comprising: bupivacaine residing inside a plurality of
internal aqueous chambers of the MVLs separated by lipid membranes,
wherein the lipid membranes comprise
1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; and an aqueous medium in which the
bupivacaine encapsulated MVLs are suspended; wherein the
composition has an initial pH of about 7.0 to about 7.4, and
wherein erucic acid concentration in the composition is about 23
.mu.g/mL or less after the composition is stored at 25.degree. C.
for one month.
[0025] Some additional aspect of the present disclosure relates to
a composition of bupivacaine encapsulated multivesicular liposomes
(MVLs) prepared by a commercial scale process, the commercial scale
process comprising: [0026] (a) mixing a first aqueous solution
comprising phosphoric acid with a volatile water-immiscible solvent
solution to form a water-in-oil first emulsion, wherein the
volatile water-immiscible solvent solution comprises bupivacaine,
1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; [0027] (b) mixing the water-in-oil
first emulsion with a second aqueous solution to form a
water-in-oil-in-water second emulsion, wherein the second aqueous
solution comprises lysine and dextrose; [0028] (c) removing the
volatile water-immiscible solvent from the water-in-oil-in-water
second emulsion to form a first aqueous suspension of bupivacaine
encapsulated MVLs having a first volume; [0029] (d) reducing the
first volume of the first aqueous suspension of bupivacaine
encapsulated MVLs by microfiltration to provide a second aqueous
suspension of bupivacaine encapsulated MVLs having a second volume;
[0030] (e) exchanging the aqueous supernatant of the second aqueous
suspension with a saline solution by diafiltration to provide a
third aqueous suspension of bupivacaine encapsulated MVLs having a
third volume; and [0031] (f) further reducing the third volume of
the third aqueous suspension by microfiltration to provide a final
aqueous suspension of bupivacaine encapsulated MVLs having a target
concentration of bupivacaine; [0032] wherein all steps are carried
out under aseptic conditions; and [0033] wherein the internal pH of
the bupivacaine encapsulated MVLs in the composition is about 5.50.
In some embodiments, the internal pH is measured after the
composition has been stored at about 2-8.degree. C. for at least 3
months, 6 months or 9 months.
[0034] Some additional aspect of the present disclosure relates to
a composition of bupivacaine encapsulated multivesicular liposomes
(MVLs), comprising: bupivacaine residing inside a plurality of
internal aqueous chambers of the MVLs separated by lipid membranes,
wherein the lipid membranes comprise
1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; and an aqueous medium in which the
bupivacaine encapsulated MVLs are suspended; wherein the internal
pH of the bupivacaine encapsulated MVLs is about 5.50.
[0035] In any aspects of the disclosure described herein, the
composition of bupivacaine MVLs is suitable for human
administration without further purification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In addition to the features described above, additional
features and variations will be readily apparent from the following
descriptions of the drawings and exemplary embodiments. It is to be
understood that these drawings depict typical embodiments, and are
not intended to be limiting in scope.
[0037] FIG. 1A illustrates a process flow chart of the formation of
an initial aqueous suspension bupivacaine MVLs according to an
embodiment of the manufacturing process described herein.
[0038] FIG. 1B illustrates a process flow chart of additional steps
of concentration, filtration and solvent removal of the initial
aqueous suspension of bupivacaine MVLs according to an embodiment
of the manufacturing process described herein.
[0039] FIG. 2 illustrate a crossflow filtration system according to
an embodiment of the manufacturing process described herein.
[0040] FIG. 3A is a line chart showing supernatant pH as a function
of incubation time at 25.degree. C. for bupivacaine-MVL
compositions prepared according to a manufacturing process
described herein as compared to bupivacaine-MVL compositions using
the existing manufacturing process.
[0041] FIG. 3B is a line chart showing erucic acid concentration as
a function of incubation time at 25.degree. C. for bupivacaine-MVL
compositions prepared according to a manufacturing process
described herein as compared to bupivacaine-MVL compositions
prepared by the existing commercial manufacturing process.
[0042] FIG. 3C is a chart showing erucic acid concentration as a
function of supernatant pH at 25.degree. C. for bupivacaine-MVL
compositions prepared according to a manufacturing process
described herein as compared to bupivacaine-MVL compositions
prepared by the existing commercial manufacturing process.
DETAILED DESCRIPTION
[0043] Embodiments of the present disclosure relate to new and
improved commercial scale manufacturing processes for making
bupivacaine encapsulated multivesicular liposomes (MVLs). The newly
developed processes provide up to 5 folds increase in final product
volume as compared to the current process used for the
manufacturing of Exparel.RTM., which is disclosed in U.S. Pat. No.
9,585,838 and is incorporated by reference in its entirety. The
processes also allow for improved product operability. In addition,
the improved and scaled up process also yields a more stabilized
form of bupivacaine encapsulated MVLs, having less lipid
degradation byproducts, increased internal pH, and increased lysine
and dextrose encapsulation.
Definitions
[0044] The section headings used herein are for organizational
purposes only and are not to be construed as limiting the subject
matter described.
[0045] As used herein, the terms "bupivacaine encapsulated
multivesicular liposomes", "bupivacaine-MVLs" or "bupivacaine MVLs"
refer to a multivesicular liposome composition encapsulating
bupivacaine. In some embodiments, the composition is a
pharmaceutical formulation, where the bupivacaine encapsulated
multivesicular liposome particles are suspended in a liquid
suspending medium to form a suspension. In some such embodiments,
the BUP-MVL suspension may also include free or unencapsulated
bupivacaine. In some cases, the free or unencapsulated bupivacaine
may be less than about 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.2%
or 0.1%, by weight of the total amount of the bupivacaine in the
composition, or in a range defined by any of the two preceding
values. In some embodiment, the free bupivacaine may be about 5% or
less by weight of the total amount of the bupivacaine in the
composition. In further embodiments, the free bupivacaine may be
about 8% or less during the shelf life of the product (i.e., up to
2 years when stored at 2-8.degree. C.).
[0046] As used herein, the term "encapsulated" means that
bupivacaine is inside a liposomal particle, for example, the MVL
particles. In some instances, bupivacaine may also be on an inner
surface, or intercalated in a membrane, of the MVLs.
[0047] As used herein, the term "unencapsulated bupivacaine" or
"free bupivacaine" refers to bupivacaine outside the liposomal
particles, for example the MVL particles. For example,
unencapsulated bupivacaine may reside in the suspending solution of
these particles.
[0048] As used herein, the term "median particle diameter" refers
to volume weighted median particle diameter of a suspension.
[0049] As used herein, a "pH adjusting agent" refers to a compound
that is capable of modulating the pH of an aqueous phase.
[0050] As used herein, the terms "tonicity" and "osmolality" are
measures of the osmotic pressure of two solutions, for example, a
test sample and water separated by a semi-permeable membrane.
Osmotic pressure is the pressure that must be applied to a solution
to prevent the inward flow of water across a semi-permeable
membrane. Osmotic pressure and tonicity are influenced only by
solutes that cannot readily cross the membrane, as only these exert
an osmotic pressure. Solutes able to freely cross the membrane do
not affect tonicity because they will become equal concentrations
on both sides of the membrane. An osmotic pressure provided herein
is as measured on a standard laboratory vapor pressure or freezing
point osmometer.
[0051] As used herein, the term "sugar" as used herein denotes a
monosaccharide or an oligosaccharide. A monosaccharide is a
monomeric carbohydrate which is not hydrolysable by acids,
including simple sugars and their derivatives, e.g. aminosugars.
Examples of monosaccharides include sorbitol, glucose, fructose,
galactose, mannose, sorbose, ribose, deoxyribose, dextrose,
neuraminic acid. An oligosaccharide is a carbohydrate consisting of
more than one monomeric saccharide unit connected via glycosidic
bond(s) either branched or in a chain. The monomeric saccharide
units within an oligosaccharide can be the same or different.
Depending on the number of monomeric saccharide units the
oligosaccharide is a di-, tri-, tetra-, penta- and so forth
saccharide. In contrast to polysaccharides, the monosaccharides and
oligosaccharides are water soluble. Examples of oligosaccharides
include sucrose, trehalose, lactose, maltose and raffinose.
[0052] As used herein, the term "amphipathic lipids" include those
having a net negative charge, a net positive charge, and
zwitterionic lipids (having no net charge at their isoelectric
point).
[0053] As used herein, the term "neutral lipid" refers to oils or
fats that have no vesicle-forming capabilities by themselves, and
lack a charged or hydrophilic "head" group. Examples of neutral
lipids include, but are not limited to, glycerol esters, glycol
esters, tocopherol esters, sterol esters which lack a charged or
hydrophilic "head" group, and alkanes and squalenes.
[0054] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as is commonly understood by one
of ordinary skill in the art. All patents, applications, published
applications and other publications referenced herein are
incorporated by reference in their entirety unless stated
otherwise. In the event that there are a plurality of definitions
for a term herein, those in this section prevail unless stated
otherwise. As used in the specification and the appended claims,
the singular forms "a," "an" and "the" include plural referents
unless the context clearly dictates otherwise. Unless otherwise
indicated, conventional methods of mass spectroscopy, NMR, HPLC,
protein chemistry, biochemistry, recombinant DNA techniques and
pharmacology are employed. The use of "or" or "and" means "and/or"
unless stated otherwise. Furthermore, use of the term "including"
as well as other forms, such as "include", "includes," and
"included," is not limiting. As used in this specification, whether
in a transitional phrase or in the body of the claim, the terms
"comprise(s)" and "comprising" are to be interpreted as having an
open-ended meaning. That is, the terms are to be interpreted
synonymously with the phrases "having at least" or "including at
least." When used in the context of a process, the term
"comprising" means that the process includes at least the recited
steps, but may include additional steps. When used in the context
of a compound, composition, or device, the term "comprising" means
that the compound, composition, or device includes at least the
recited features or components, but may also include additional
features or components.
Manufacturing Processes
[0055] Some embodiments of the present application relate to a
commercial scale manufacturing process for preparing bupivacaine
encapsulated multivesicular liposomes. The process comprising:
[0056] (a) mixing a first aqueous solution comprising phosphoric
acid with a volatile water-immiscible solvent solution to form a
water-in-oil first emulsion, wherein the volatile water-immiscible
solvent solution comprises bupivacaine, at least one amphipathic
lipid and at least one neutral lipid; [0057] (b) mixing the
water-in-oil first emulsion with a second aqueous solution to form
a water-in-oil-in-water second emulsion; [0058] (c) removing the
volatile water-immiscible solvent from the water-in-oil-in-water
second emulsion to form a first aqueous suspension of bupivacaine
encapsulated multivesicular liposomes having a first volume; [0059]
(d) reducing the first volume of the first aqueous suspension of
bupivacaine encapsulated multivesicular liposomes by
microfiltration to provide a second aqueous suspension of
bupivacaine encapsulated multivesicular liposomes having a second
volume; [0060] (e) exchanging the aqueous supernatant of the second
aqueous suspension with a saline solution by diafiltration to
provide a third aqueous suspension of bupivacaine encapsulated
multivesicular liposomes having a third volume; and [0061] (f)
further reducing the third volume of the third aqueous suspension
by microfiltration to provide a final aqueous suspension of
bupivacaine encapsulated multivesicular liposomes having a target
concentration of bupivacaine; [0062] wherein all steps are carried
out under aseptic conditions.
[0063] In some embodiments of the process, the amphipathic lipid in
the volatile water-immiscible solvent solution may be chosen from a
wide range of lipids having a hydrophobic region and a hydrophilic
region in the same molecule. Suitable amphipathic lipids include,
but are not limited to zwitterionic phospholipids, including
phosphatidylcholines, phosphatidylethanolamines, sphingomyelins,
lysophosphatidylcholines, and lysophosphatidylethanolamines;
anionic amphipathic phospholipids such as phosphatidylglycerols,
phosphatidylserines, phosphatidylinositols, phosphatidic acids, and
cardiolipins; cationic amphipathic lipids such as acyl
trimethylammonium propanes, diacyl dimethylammonium propanes,
stearylamine, and the like. Non-limiting exemplary phosphatidyl
cholines include dioleyl phosphatidyl choline (DOPC), 1,2-dierucoyl
phosphatidylcholine or 1,2-dierucoyl-sn-glycero-3-phosphocholine
(DEPC), 1,2-didecanoyl-sn-glycero-3-phosphocholine (DDPC),
1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLOPC),
1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC),
1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC),
1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC),
1,2-distearoyl-sn-glycero-3-phospho choline (DSPC),
1-myristoyl-2-palmitoyl-sn-glycero 3-phosphocholine (MPPC),
1-myristoyl-2-stearoyl-sn-glycero-3-phosphocholine (MSPC),
1-palmitoyl-2-myristoyl-sn-glycero-3-phosphocholine (PMPC),
1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC),
1-palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine (PSPC),
1-stearoyl-2-myristoyl-sn-glycero-3-phosphocholine (SMPC),
1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC), or
1-stearoyl-2-palmitoyl-sn-glycero-3-phosphocholine (SPPC).
Non-limiting examples of phosphatidyl glycerols include
dipalmitoylphosphatidylglycerol or
1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG),
1,2-dierucoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DEPG),
1,2-dilauroyl-sn-glycero-3-phospho-rac-(1-glycerol) (DLPG),
1,2-dimyristoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DMPG),
1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG),
1,2-distearoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DSPG),
1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (POPG),
or salts thereof, for example, the corresponding sodium salts,
ammonium salts, or combinations of the salts thereof. In some such
embodiments, the amphipathic lipid comprises phosphatidylcholine,
or phosphatidylglycerol or salts thereof, or combinations thereof.
In some embodiments, the phosphatidyl choline is DEPC. In some
embodiments, the phosphatidyl glycerol is DPPG. In some
embodiments, the amphipathic lipid comprises DEPC and DPPG. In
further embodiments, the DEPC and the DPPG are present in MVLs in a
mass ratio of DEPC:DPPG of about 15:1 to about 20:1, or about 17:1.
In further embodiments, the total DEPC and DPPG in the MVLs
suspension is in a mass ratio of about 7:1 to about 10:1, or about
8:1.
[0064] In some embodiments, suitable neutral lipids in the volatile
water-immiscible solvent solution may include but are not limited
to triglycerides, propylene glycol esters, ethylene glycol esters,
and squalene. Non-limiting exemplary triglycerides useful in the
instant formulations and processes are triolein (TO),
tripalmitolein, trimyristolein, trilinolein, tributyrin,
tricaproin, tricaprylin (TC), and tricaprin. The fatty acid chains
in the triglycerides useful in the present application can be all
the same, or not all the same (mixed chain triglycerides), or all
different. In one embodiment, the neutral lipid comprises or is
tricaprylin. In further embodiments, the volatile water-immiscible
solvent solution in step (a) of the process may further comprise
cholesterol and/or a plant sterol.
[0065] In some embodiments of the process described herein, the
mixing in step (a) is performed using a first mixer at a high shear
speed. In some embodiments, the high sheer speed is from about 1100
rpm to about 1200 rpm, for example, 1100 rpm, 1110 rpm, 1120 rpm,
1130 rpm, 1140 rpm, 1150 rpm, 1160 rpm, 1170 rpm, 1180 rpm, 1190
rpm, or 1200 rpm, or a range defined by any of the two preceding
values. In some embodiment, the high sheer speed is about 1150 rpm.
In some embodiments, the mixing in step (a) is performed for about
65 minutes, 66 minutes, 67 minutes, 68 minutes, 69 minutes, 70
minutes, 71 minutes, 72 minutes, 73 minutes, 74 minutes or 75
minutes. Proper mixing rate is important for forming the first
emulsion droplets in a proper size range, which is important to the
final product yield, the MVL particle stability and release
properties. It was observed that when the mixing speed is too low
or too high, the droplets formed in the first emulsion were either
too big or too small. In some further embodiments, the first mixer
used in step (a) of the process has a blade diameter of between
about 8 inch to about 10 inch. In further embodiments, the first
mixer used in step (a) of the process is not a static mixer. In
further embodiments, the mixing in step (a) is performed at a
temperature of about 21.degree. C. to about 23.degree. C.
[0066] In some embodiments of the process described herein, the
mixing in step (b) is performed using a second mixer at a low shear
speed. In some embodiments, the low sheer speed is from about 450
rpm to about 510 rpm, for example, 450 rpm, 455 rpm, 460 rpm, 465
rpm, 470 rpm, 475 rpm, 480 rpm, 485 rpm, 490 rpm, 495 rpm, 500 rpm,
505 rpm, or 510 rpm, or a range defined by any of the two preceding
values. In some embodiment, the low sheer speed is about 495 rpm.
In some embodiments, the mixing in step (b) is performed for about
60 seconds, 61 seconds, 62 seconds, 63 seconds, 64 seconds, or 65
seconds. In some further embodiments, the second mixer used in step
(b) of the process has a blade diameter of between about 10 inch to
about 15 inch, for example, 10 inch, 11 inch, 12 inch, 13 inch, or
14 inch. In further embodiments, the second mixer used in step (b)
of the process is not a static mixer. In further embodiments, the
mixing in step (b) is performed at a temperature of about
21.degree. C. to about 23.degree. C. The water-in-oil-in water
(w/o/w) second emulsion is not as stable as the first emulsion. As
such, a low shear speed was used in mixing step to reduce the
disruption of the spherules formed in this step. In addition, the
mixing time in step (b) is also important to yield the final MVL
particles in the target diameters and have the desired release
properties. If mixing time is too short, it led to a larger
particle size.
[0067] In some embodiments of the process described herein, the
second aqueous solution comprises one or more pH modifying agents.
The pH modifying agents that may be used in the present MVL
formulations are selected from organic acids, organic bases,
inorganic acids, or inorganic bases, or combinations thereof.
Suitable organic bases that can be used in the present application
include, but are not limited to histidine, arginine, lysine,
tromethamine (Tris), etc. Suitable inorganic bases that can be used
in the present application include, but are not limited to sodium
hydroxide, calcium hydroxide, magnesium hydroxide, potassium
hydroxide, etc. Suitable inorganic acids (also known as mineral
acids) that can be used in the present application include, but are
not limited to hydrochloric acid (HCl), sulfuric acid
(H.sub.2SO.sub.4), phosphoric acid (H.sub.3PO.sub.4), nitric acid
(HNO.sub.3), etc. Suitable organic acids that can be used in the
present application include, but are not limited to acetic acid,
aspartic acid, citric acid, formic acid, glutamic acid, glucuronic
acid, lactic acid, malic acid, tartaric acid, etc. In one
embodiment, the pH modifying agent comprises lysine.
[0068] In some embodiments of the process described herein, the
second aqueous solution comprises one or more tonicity agents.
Tonicity agents sometimes are also called osmotic agents.
Non-limiting exemplary osmotic agents suitable for the MVL
formulation of the present application include monosaccharides
(e.g., glucose, and the like), disaccharides (e.g., sucrose and the
like), polysaccharide or polyols (e.g., sorbitol, mannitol,
Dextran, and the like), or amino acids. In some embodiments, one or
more tonicity agents may be selected from an amino acid, a sugar,
or combinations thereof. In some further embodiments, one or more
tonicity agents are selected from dextrose, sorbitol, sucrose,
lysine, or combinations thereof. In one embodiment, the tonicity
agent comprises dextrose. In some further embodiments, the second
aqueous solution comprises lysine and dextrose.
[0069] In some embodiments of the process described herein, the
volatile water-immiscible organic solvent comprises or is methylene
chloride (CH.sub.2Cl.sub.2). The organic solvent is substantially
removed by exposing the second emulsion to a gas atmosphere.
Organic solvent may be removed by blowing a gas over the second
emulsion, or sparging gas in the second emulsion, or spraying the
second emulsion into a chamber with a continuous stream of
circulating gas.
[0070] In some embodiments of the process described herein, wherein
step (e) is performed using two sets of filtration modules, wherein
each set of the filtration modules operate independently of the
other. In further embodiments, each set of the filtration module
comprises five or more hollow fiber filters, each having a membrane
pore size from about 0.1 .mu.m to about 0.2 .mu.m. One embodiment
of the filtration modules is illustrated in FIG. 2.
[0071] In some embodiments of process described herein, the
diafiltration step (e) is performed multiple times until the
aqueous supernatant of the second aqueous suspension is
substantially replaced with the saline solution.
[0072] In some embodiments of process described herein, step (f)
may be performed multiple times until a target concentration of
bupivacaine MVLs is reached. In some further embodiments, the final
aqueous suspension of bupivacaine encapsulated multivesicular
liposomes is transferred to a bulk product vessel.
[0073] FIGS. 1A-1B are process flow charts, each depicting a
portion of the bupivacaine MVLs manufacturing process 100 according
to some embodiments described herein. The circled A symbol
indicates the connection point between FIG. 1A and FIG. 1B. As
shown in FIGS. 1A-1B, bupivacaine MVLs is produced via an aseptic
double-emulsion process. The bulk manufacturing system is a closed,
sterilized system into which all process solutions are
sterile-filtered through 0.2 .mu.m filters.
[0074] As shown in FIG. 1A, the process 100 includes a step 102,
wherein DEPC, DPPG, cholesterol, tricaprylin, and bupivacaine are
dissolved in methylene chloride to form a lipid/drug solution 102.
At a step 103, the lipid solution is filtered through a 0.2 .mu.m
membrane filter into a sterilized vessel. At a step 104, phosphoric
acid is dissolved in WFI (water for injection) to form a
H.sub.3PO.sub.4 solution. At a step 105, the H.sub.3PO.sub.4
solution is filtered through a 0.2 .mu.m membrane filter into a
sterilized vessel. Under aseptic conditions, the filtered
lipid/drug solution is combined with the filtered H.sub.3PO.sub.4
solution in a volume ratio of 1:1 at an emulsification step 106
using agitation to produce a w/o emulsion (i.e., first emulsion).
High shear mixing of the lipid/drug solution with the phosphoric
acid solution is performed, wherein bupivacaine is ionized by the
phosphoric acid and partitions into the internal aqueous phase. At
a step 107, lysine and dextrose are combined in WFI to form a
dextrose/lysine solution. At a step 108, the dextrose/lysine
solution is filtered through a 0.2 .mu.m membrane filter into a
sterilized vessel. Under aseptic conditions, the filtered
dextrose/lysine solution is added to the w/o emulsion in a volume
ratio of approximately 2.5:1 at an emulsification step 109 using
agitation to produce a w/o/w emulsion (i.e., second emulsion). At
emulsification step 109, agitation is performed at lower shear,
producing a water-in-oil-in-water (w/o/w) emulsion with the
majority of the bupivacaine resident in the internal aqueous phase.
Additional filtered dextrose/lysine solution is added to the w/o/w
emulsion at a dilution step 110 to form a diluted suspension of
MVLs and bringing the final volume ratio to approximately 20:1
(dextrose/lysine solution to water-in-oil emulsion) with mixing. At
a step 111, the diluted suspension of MVLs is sparged with sterile
nitrogen to remove the majority of the methylene chloride.
[0075] FIG. 1B depicts additional steps of the process 100. After
sparging at step 111, the diluted suspension of bupivacaine MVLs is
concentrated via aseptic microfiltration at a step 112 to a
bupivacaine concentration of approximately 4.5 mg/mL.
[0076] At a step 113, a NaCl solution is formed by dissolving
sodium chloride in WFI. At a step 114, the NaCl solution (i.e.,
saline solution) is filtered through a 0.2 .mu.m membrane filter.
Under aseptic conditions, the bupivacaine MVLs concentrate formed
at step 112 is subjected to crossflow filtration by at least four
volumes of the filtered NaCl solution through introduction of the
filtered NaCl solution into a crossflow filtration apparatus or
system through multiple 0.2 .mu.m hollow fiber filter membrane unit
filters at a diafiltration step 115. Diafiltration step 115 is used
to remove unencapsulated bupivacaine, lysine, dextrose and residual
methylene chloride, thereby reducing the suspension volume and
increasing the concentration of the bupivacaine MVLs in the
suspension. At a step 116, sterile nitrogen is used to flush the
headspace of the crossflow filtration apparatus or system to
further reduce residual methylene chloride content. The solution is
further concentrated via aseptic microfiltration in concentrate
step 117 to form an initial bulk suspension of MVLs at a target
weight/volume that corresponds to a bupivacaine concentration of
11.3-16.6 mg/mL. The bulk product is then transferred into a
sterilized holding vessel. The initial bulk suspension of MVLs is
sampled and bupivacaine concentration is measured. Optionally, if
the initial bulk suspension of MVLs is designated to be filled as
an individual lot, the initial bulk suspension of MVLs is
concentrated further via sedimentation (gravitational settling)
and/or decantation to a bupivacaine concentration of approximately
13.3 mg/mL, or alternatively diluted with a filtered NaCl solution
to a bupivacaine concentration of approximately 13.3 mg/mL at a
decantation and/or dilution step 120 to form an adjusted bulk
suspension of MVLs. The saline solution that is optionally used at
step 120 can be formed by dissolving sodium chloride in WFI at a
step 118 and filtered through a 0.2 .mu.m membrane filter at a step
119.
Tangential Flow Filtration Modules
[0077] Some embodiments of the present application relates to a
crossflow filtration system comprising: a diafiltration vessel; and
a plurality of independently operating crossflow modules, each
crossflow module of the plurality of independently operating
crossflow modules comprising at least one filter array, each filter
array comprising a plurality of hollow fiber filters, wherein each
crossflow module of the plurality of independently operating
crossflow modules is connected to a retentate conduit, a permeate
conduit, and a rotary lobe pump. In some embodiments, the crossflow
filtration system may be used in the microfiltration and/or
diafiltration step of the commercial process described herein.
[0078] In some embodiments, each crossflow module comprises two
filter arrays. In some embodiments, each crossflow module comprises
at least five hollow fiber filters. In some such embodiments, each
filter array comprises at least two hollow fiber filters.
[0079] In some embodiments, the plurality of independently
operating crossflow modules comprises a first crossflow module and
a second crossflow module, wherein the first crossflow module is
coupled to a first rotary lobe pump and the second crossflow module
is coupled to a second rotary lobe pump operating independently of
the first rotary lobe pump. In some further embodiments, the first
crossflow module is coupled to the diafiltration vessel by a first
retentate conduit to facilitate flow of retentate from the first
crossflow module to the diafiltration vessel, and wherein the
second crossflow module is coupled to the diafiltration vessel by a
second retentate conduit to facilitate flow of retentate from the
second crossflow module to the diafiltration vessel. In some
further embodiments, the first rotary lobe pump comprises a fluid
outlet coupling the first rotary lobe pump to the first crossflow
module, and wherein the second rotary lobe pump comprises a fluid
outlet coupling the second rotary lobe pump to the first crossflow
module. In some further embodiments, the first rotary lobe pump
comprises a fluid inlet coupling the first rotary lobe pump to the
diafiltration vessel, and wherein the second rotary lobe pump
comprises a fluid inlet coupling the second rotary lobe pump to the
diafiltration vessel.
[0080] In some embodiments, the first crossflow module operates
independently from the second crossflow module. In some such
embodiments, only one of the first crossflow module and the second
crossflow module is in use during the operation of the crossflow
filtration system. In other embodiments, both the first crossflow
module and the second crossflow module are in use during the
operation of the crossflow filtration system.
[0081] In some embodiments, each of the plurality of independently
operating crossflow modules comprises a microfiltration mode and a
diafiltration mode.
[0082] In some embodiments, the crossflow filtration system further
comprises a nitrogen sparging module to blow a stream nitrogen over
the retentate in the diafiltration vessel.
[0083] Some further embodiments of the present application relate
to a process of manufacturing bupivacaine encapsulated
multivesicular liposomes using the cross-flow module described
herein, the process comprising: [0084] reducing a first aqueous
suspension of bupivacaine encapsulated MVLs having a first volume
by microfiltration to provide a second aqueous suspension of
bupivacaine encapsulated MVLs having a second volume; [0085]
exchanging the aqueous supernatant of the second aqueous suspension
with a saline solution by diafiltration to provide a third aqueous
suspension of bupivacaine encapsulated MVLs having a third volume;
and [0086] further reducing the third volume of the third aqueous
suspension by microfiltration to provide a final aqueous suspension
of bupivacaine encapsulated MVLs having a target concentration of
bupivacaine.
[0087] In some embodiments, the process further comprises blowing a
stream of nitrogen over the second aqueous suspension during the
diafiltration/saline exchange step. In some further embodiments,
the diafiltration include at least two, three, four or five
exchange volumes of the saline solution such that the aqueous
supernatant of the second aqueous suspension is substantially
(e.g., at least 95%, 96%, 97%, 98%, 99%) replaced by the saline
solution.
[0088] Some further embodiments relate to a composition of
bupivacaine encapsulated multivesicular liposomes prepared by the
process utilizing the crossflow filtration system described
herein.
[0089] FIG. 2 depicts an embodiment of a crossflow filtration
system 200 for use in a diafiltration step of a commercial scale
manufacturing process as described herein, such as step 115 of the
process 100. The system 200 includes independently operating
crossflow modules 202a and 202b. Crossflow module 202a includes a
filter array 204a and a filter array 204b. Crossflow module 202b
includes a filter array 204c and a filter array 204d. Each filter
array 204a-d may include two or more hollow fiber filters. In some
embodiments, each filter array includes five or more hollow fiber
filters.
[0090] The system may be connected to a sparge/diafiltration vessel
206. Retentate can flow from the crossflow module 202a to the
vessel 206 via a retentate return conduit 208a. Retentate can flow
from the crossflow module 202b to the vessel 206 via a retentate
return conduit 208b. Permeate can flow from the crossflow module
202a for removal from the system 200 via a permeate conduit 210a.
Permeate can flow from the crossflow module 202b for removal from
the system 200 via a permeate conduit 210b.
[0091] The system 200 may include or be used in conjunction with
two independently operating rotary lobe pumps 212a and 212b. The
pump 212a includes a fluid inlet 214a and a fluid outlet 216a. The
pump 212b includes a fluid inlet 214b and a fluid outlet 216b. The
pump 212a is connected to the vessel 206 via the inlet 214a and
connected to crossflow module 202a via the outlet 216a. The pump
212b is connected to the vessel 206 via the inlet 214b and
connected to the crossflow module 202b via the outlet 216b.
[0092] In some embodiments of the process described herein, the
crossflow filtration system utilizes two independent rotary lobe
pumps providing retentate flow to independent arrays of five hollow
fiber filter housings. This configuration allows for smaller pipe
diameters to allow for turbulent flow. In addition, the filtration
module design allows for two filter arrays to be in-use during bulk
operation while two filter arrays are being cleaned and sterilized
in preparation for the next bulk production run. This configuration
allows for shorter cycle times and increased manufacturing
capacity. Furthermore, the improved filtration module design allows
for independent hollow fiber filter housing isolation. This
functionality automatically detects and isolates individual filter
integrity failures, allowing the bulk cycle to proceed without
offline testing and recleaning. In some further embodiments, the
process may further comprise an additional product recovery step
from one of the two filter array and/or a saline flush step, to
allow for nearly complete product recover from the transfer lines
and thereby increasing product yield.
[0093] In some embodiments of the process described herein, the
final aqueous suspension of bupivacaine encapsulated multivesicular
liposomes has a volume of about 150 L to about 250 L. In one
embodiment, the final aqueous suspension of bupivacaine
encapsulated multivesicular liposomes has a volume of about 200 L.
In another embodiment, the final aqueous suspension of bupivacaine
encapsulated multivesicular liposomes has a volume of about 225 L.
In some embodiments, the percent packed particle volume (% PPV) of
the final aqueous suspension of bupivacaine encapsulated
multivesicular liposomes is about 32% to about 44%, about 35% to
about 40%, or about 36% to about 38%. In some such embodiments, the
target concentration of the bupivacaine in the final aqueous
suspension (i.e., bulk product suspension) is from about 12.6 mg/mL
to about 17 mg/mL. In further embodiments, the final product target
concentration of the bupivacaine in the aqueous suspension is about
13.3 mg/mL. In some embodiments, the final aqueous suspension of
bupivacaine MVLs comprises less than 5%, 4%, 3%, 2% or 1%
unencapsulated bupivacaine, wherein the amount of unencapsulated
bupivacaine is calculate based on the total weight of the
bupivacaine in the aqueous suspension. In some embodiments, the
d.sub.50 of the multivesicular liposomes in the final aqueous
suspension is about 24 .mu.m to about 31 .mu.m. In one embodiment,
the d.sub.50 of the multivesicular liposomes in the final aqueous
suspension is about 27 .mu.m. In some embodiments, the internal pH
of the bupivacaine encapsulated multivesicular liposomes is about
5.5. In some such embodiments, the lysine concentration inside the
bupivacaine multivesicular liposome particles (i.e., internal
lysine concentration or encapsulated lysine concentration) is about
0.08 mg/mL. In further embodiments, the internal lysine
concentration is about 0.03 mg/mL, where the lysine concentration
is measured when the MVL particles are in the aqueous suspension.
In some embodiments, the external pH of the bupivacaine
encapsulated multivesicular liposomes is about 7.0 to about 7.4. As
used herein, "internal pH" of the bupivacaine MVLs refer to the pH
of the internal aqueous chambers of the MVL particles. The pH of
the aqueous suspension of the bupivacaine MVLs is also referred to
as the "external pH" of the bupivacaine MVLs. In some embodiments,
the external pH of the bupivacaine MVLs are measured during the
product's shelf life under the storage condition between
2-8.degree. C. When the bupivacaine MVLs are stored at ambient
temperature at extended period of time, the external pH of the
composition may drop below the 7.0-7.4 range partially due to the
accelerated lipid hydrolysis.
Bupivacaine Multivesicular Liposomes Prepared by the New
Process
[0094] MVLs are a group of unique forms of synthetic membrane
vesicles that are different from other lipid-based delivery systems
such as unilamellar liposomes and multilamellar liposomes (Bangham,
et al., J Mol. Bio., 13:238-252, 1965). The main structural
difference between multivesicular liposomes and unilamellar
liposomes (also known as unilamellar vesicles, "ULVs"), is that
multivesicular liposomes contain multiple aqueous chambers per
particle. The main structural difference between multivesicular
liposomes and multilamellar liposomes (also known as multilamellar
vesicles, "MLVs"), is that in multivesicular liposomes the multiple
aqueous chambers are non-concentric. Multivesicular liposomes
generally have between 100 to 1 million chambers per particle and
all the internal chambers are interconnected by shared
lipid-bilayer walls that separate the chambers. The presence of
internal membranes distributed as a network throughout
multivesicular liposomes may serve to confer increased mechanical
strength to the vesicle. The particles themselves can occupy a very
large proportion of the total formulation volume. Such formulation
is intended to prolong the local delivery of bupivacaine, thereby
enhancing the duration of action of the reduction of pain.
[0095] The bupivacaine MVLs produced by the process described
herein have improved stability over the commercial Exparel.RTM.
product. It was observed that the bupivacaine MVL particles
produced by the process described herein have lower lipid
hydrolysis byproducts compared to the commercial Exparel.RTM.
product under the same incubation condition. In addition, the
bupivacaine MVL particles produced by the process described herein
has higher internal lysine and dextrose concentrations and more
desirable internal pH, which may improve MVL particle strength
during product transportation, as well as lipid membrane
stability.
[0096] Some embodiments of the present disclosure relate to a
composition of bupivacaine encapsulated multivesicular liposomes
(MVLs) prepared by a commercial scale process described herein, the
commercial scale process comprising: [0097] (a) mixing a first
aqueous solution comprising phosphoric acid with a volatile
water-immiscible solvent solution to form a water-in-oil first
emulsion, wherein the volatile water-immiscible solvent solution
comprises bupivacaine, 1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; [0098] (b) mixing the water-in-oil
first emulsion with a second aqueous solution to form a
water-in-oil-in-water second emulsion; [0099] (c) removing the
volatile water-immiscible solvent from the water-in-oil-in-water
second emulsion to form a first aqueous suspension of bupivacaine
encapsulated MVLs having a first volume; [0100] (d) reducing the
first volume of the first aqueous suspension of bupivacaine
encapsulated MVLs by microfiltration to provide a second aqueous
suspension of bupivacaine encapsulated MVLs having a second volume;
[0101] (e) exchanging the aqueous supernatant of the second aqueous
suspension with a saline solution by diafiltration to provide a
third aqueous suspension of bupivacaine encapsulated MVLs having a
third volume; and [0102] (f) further reducing the third volume of
the third aqueous suspension by microfiltration to provide a final
aqueous suspension of bupivacaine encapsulated MVLs having a target
concentration of bupivacaine; [0103] wherein all steps are carried
out under aseptic conditions; and [0104] wherein the erucic acid
concentration in the composition is about 23 .mu.g/mL or less after
the composition is stored at 25.degree. C. for one month. In one
embodiment, the erucic acid concentration in the composition is
about 22.7 .mu.g/mL after the composition is stored at 25.degree.
C. for one month.
[0105] In some embodiments, the final aqueous suspension of
bupivacaine encapsulated MVLs described in the process is the
composition of the bupivacaine MVLs described herein. In other
embodiments, the concentration of the final aqueous suspension of
bupivacaine encapsulated MVLs described in the process may be
further adjusted with a saline solution to provide the composition
of the bupivacaine MVLs described herein. In some embodiments, the
composition has a pH of about 7.1 after the composition is stored
at 25.degree. C. for one month.
[0106] In some further embodiments, the erucic acid concentration
in the composition is about 38 .mu.g/mL or less after the
composition is stored at 25.degree. C. for two months. In one
embodiment, the erucic acid concentration in the composition is
about 37.3 .mu.g/mL after the composition is stored at 25.degree.
C. for two months. In some such embodiments, the composition has a
pH of about 7.1 after the composition is stored at 25.degree. C.
for two months.
[0107] In some further embodiments, the erucic acid concentration
in the composition is about 54 .mu.g/mL or less after the
composition is stored at 25.degree. C. for three months. In one
embodiment, the erucic acid concentration in the composition is
about 53 .mu.g/mL after the composition is stored at 25.degree. C.
for three months. In some such embodiments, the composition has a
pH of about 6.9 after the composition is stored at 25.degree. C.
for three months.
[0108] In some further embodiments, the erucic acid concentration
in the composition is about 100 .mu.g/mL or less after the
composition is stored at 25.degree. C. for six months. In one
embodiment, the erucic acid concentration in the composition is
about 98.7 .mu.g/mL after the composition is stored at 25.degree.
C. for six months. In some further embodiments, the composition has
a pH of about 6.5 after the composition is stored at 25.degree. C.
for six months.
[0109] In some embodiments, the composition of bupivacaine MVLs
comprises the following lipid components: DEPC, DPPG, cholesterol
and tricaprylin. In some embodiments, the total concentrations of
the lipid components in the composition are the following: DEPC
(about 7.0 mg/mL), DPPG (about 0.9 mg/mL), cholesterol (about 4.2
mg/mL), tricaprylin (about 1.6 mg/mL). Since DEPC has the highest
concentration of all the lipid components, the hydrolysis byproduct
of DEPC is used as the marker to assess lipid stability of the
MVLs. The hydrolysis byproducts of DEPC include erucic acid and
lyso-DEPC (1- and 2-isomers). Lyso-DEPC is formed by hydrolysis of
DEPC. Lyso-DEPC can further hydrolyze to glycerophosphocholine and
erucic acid. In some embodiments, the erucic acid concentration in
the composition of bupivacaine MVLs produced by the process
described herein is at least about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%,
9%, 10%, 11%, 12%, 13%, 14% or 15% less than the erucic acid
concentration in the Exparel.RTM. product manufactured by the
current commercial process, under the same incubation condition. In
some such embodiments, the incubation condition is at 25.degree.
for 1 month, 2 months, 3 months, or 6 months.
[0110] Some additional embodiments of the present disclosure relate
to a composition of bupivacaine encapsulated multivesicular
liposomes (MVLs) prepared by a commercial scale process described
herein, the commercial scale process comprising: [0111] (a) mixing
a first aqueous solution comprising phosphoric acid with a volatile
water-immiscible solvent solution to form a water-in-oil first
emulsion, wherein the volatile water-immiscible solvent solution
comprises bupivacaine, 1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; [0112] (b) mixing the water-in-oil
first emulsion with a second aqueous solution to form a
water-in-oil-in-water second emulsion, wherein the second aqueous
solution comprises lysine and dextrose; [0113] (c) removing the
volatile water-immiscible solvent from the water-in-oil-in-water
second emulsion to form a first aqueous suspension of bupivacaine
encapsulated MVLs having a first volume; [0114] (d) reducing the
first volume of the first aqueous suspension of bupivacaine
encapsulated MVLs by microfiltration to provide a second aqueous
suspension of bupivacaine encapsulated MVLs having a second volume;
[0115] (e) exchanging the aqueous supernatant of the second aqueous
suspension with a saline solution by diafiltration to provide a
third aqueous suspension of bupivacaine encapsulated MVLs having a
third volume; and [0116] (f) further reducing the third volume of
the third aqueous suspension by microfiltration to provide a final
aqueous suspension of bupivacaine encapsulated MVLs having a target
concentration of bupivacaine; [0117] wherein all steps are carried
out under aseptic conditions; and [0118] wherein the internal pH of
the bupivacaine encapsulated MVLs in the composition is about 5.50.
In some embodiments, the internal pH is measured after the
composition has been stored at about 2-8.degree. C. for at least 3
months, 6 months or 9 months. In one embodiment, the internal pH is
measured after the composition has been stored at about 2-8.degree.
C. for about 9 months.
[0119] In some embodiments, the final aqueous suspension of
bupivacaine encapsulated MVLs described in the process is the
composition of the bupivacaine MVLs described herein. In other
embodiments, the concentration of the final aqueous suspension of
bupivacaine encapsulated MVLs described in the process may be
further adjusted with a saline solution to provide the composition
of the bupivacaine MVLs described herein.
[0120] In some embodiments of the composition described herein, the
lysine concentration inside the bupivacaine encapsulated MVL
particles of the composition (internal lysine concentration or
encapsulated lysine concentration) is about 0.030 mg/mL to about
0.032 mg/mL. In some such embodiment, the internal lysine
concentration is measured when the bupivacaine MVLs are suspended
in an aqueous suspension with % PPV about 36.5%. In some further
embodiments, the internal lysine concentration inside the
bupivacaine encapsulated MVL particles is about 0.031 mg/mL.
[0121] In some embodiments of the composition described herein, the
dextrose concentration inside the bupivacaine encapsulated MVL
particles of the composition (internal dextrose concentration or
encapsulated dextrose concentration) is about 1.25 mg/mL to about
1.32 mg/mL. In some such embodiment, the internal dextrose
concentration is measured when the bupivacaine MVLs are suspended
in an aqueous suspension with % PPV about 36.5%. In some further
embodiments, the internal dextrose concentration inside the
bupivacaine encapsulated MVL particles is about 1.29 mg/mL.
[0122] Although it is expected that only phosphoric acid resides
inside the internal aqueous chambers of the MVL particles (i.e.,
the first emulsion is formed by mixing the phosphoric acid aqueous
solution with a volatile water-immiscible solvent solution).
However, there are also very small amounts of lysine and dextrose
encapsulated inside the internal aqueous chambers during the
formation of the second emulsion, which ultimately forms the MVL
particles. In some embodiments, the lysine concentration in the
bupivacaine MVLs produced by the process described herein is at
least about 5%, 10%, 15%, 20%, 25%, or 30% more than the
encapsulated lysine concentration in the Exparel.RTM. product
manufactured by the current commercial process. Since lysine is
also a pH modifying agent, the small change in lysine concentration
also results in the increase of the internal pH of the bupivacaine
MVL particles of about 5.50, as compared to the internal pH of
about 5.34 in a batch of Exparel.RTM. product manufactured by the
current commercial process. In some such embodiments, the increase
of the internal pH is characterized by the decrease in [H.sup.+]
concentration (i.e., pH=-log [H.sup.+]). In some embodiments, the
decrease in [H.sup.+] concentration in the internal aqueous
chambers of the bupivacaine MVLs is at least about 5%, 10%, 15%,
20%, 25% or 30%. As reported by Grit M. et al., phospholipids such
as phosphatidylcholine have the lowest rate of hydrolysis
regardless of the temperature of their storage at pH 6.5. See J.
Pharm. Sci. 1993; 82(4):362-366. As such, the closer the internal
pH is to 6.5, the lower the lipid hydrolysis. In some further
embodiments, the dextrose concentration in the bupivacaine MVLs
produced by the process described herein is at least about 2%, 5%,
7.5%, 10%, 12.5%, 15%, 17.5% or 20% more than the encapsulated
dextrose concentration in the Exparel.RTM. product manufactured by
the current commercial process.
[0123] In some embodiments of the composition described herein, the
mixing in step (a) is performed using a first mixer at a high shear
speed. In some embodiments, the high sheer speed is from about 1100
rpm to about 1200 rpm, for example, 1100 rpm, 1120 rpm, 1130 rpm,
1140 rpm, 1150 rpm, 1160 rpm, 1170 rpm, 1180 rpm, 1190 rpm, or 1200
rpm, or a range defined by any two of the preceding values. In some
embodiment, the high sheer speed is about 1150 rpm. In some
embodiments, the mixing in step (a) is performed for about 65
minutes, 66 minutes, 67 minutes, 68 minutes, 69 minutes, 70
minutes, 71 minutes, 72 minutes, 73 minutes, 74 minutes or 75
minutes. In some further embodiments, the first mixer used in step
(a) of the process is a mixer having a blade diameter of between
about 8 inch to about 10 inch. In further embodiments, the first
mixer used in step (a) of the process is not a static mixer. In
further embodiments, the mixing in step (a) is performed at a
temperature of about 21.degree. C. to about 23.degree. C.
[0124] In some embodiments of the composition described herein, the
mixing in step (b) is performed using a second mixer at a low shear
speed. In some embodiments, the low sheer speed is from about 450
rpm to about 510 rpm, for example, 450 rpm, 455 rpm, 460 rpm, 465
rpm, 470 rpm, 475 rpm, 480 rpm, 485 rpm, 490 rpm, 495 rpm, 500 rpm,
505 rpm, or 510 rpm, or a range defined by any of the two preceding
values. In some embodiment, the low sheer speed is about 495 rpm.
In some embodiments, the mixing in step (b) is performed for about
60 seconds, 61 seconds, 62 seconds, 63 seconds, 64 seconds, or 65
seconds. In some further embodiments, the second mixer used in step
(b) of the process has a blade diameter of between about 10 inch to
about 15 inch, for example, 10 inch, 11 inch, 12 inch, 13 inch, or
14 inch. In further embodiments, the second mixer used in step (b)
of the process is not a static mixer. In further embodiments, the
mixing in step (b) is performed at a temperature of about
21.degree. C. to about 23.degree. C.
[0125] In some embodiments of the composition described herein, the
composition of bupivacaine encapsulated multivesicular liposomes
may have a final volume of about 150 L to about 250 L, or about 200
L to about 250 L, before being filled into individual containers
for human administration. In other embodiments, the composition of
bupivacaine encapsulated MVLs may have a volume of 10 mL or 20 mL
for a single dose administration. In some embodiments, the percent
packed particle volume (% PPV) of the composition of bupivacaine
encapsulated MVLs is about 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%,
40%, 41%, 42%, 43% or 44%. In some such embodiments, the
concentration of the bupivacaine in the composition is from about
12.6 mg/mL to about 17 mg/mL. In one embodiment, the concentration
of the bupivacaine in the composition is about 13.3 mg/mL. In
further embodiments, the composition comprises less than 5%, 4%,
3%, 2% or 1% unencapsulated bupivacaine, wherein the amount of
unencapsulated bupivacaine is calculated based on the total weight
of the bupivacaine in the composition. In some embodiments, the
d.sub.50 of the multivesicular liposomes in the composition is
about 24 .mu.m to about 31 .mu.m. In one embodiment, the d.sub.50
of the multivesicular liposomes in the composition is about 27
.mu.m.
Bupivacaine Multivesicular Liposomes
[0126] Some aspect of the present disclosure relates to a
composition of bupivacaine encapsulated multivesicular liposomes
(MVLs), comprising: bupivacaine residing inside a plurality of
internal aqueous chambers of the MVLs separated by lipid membranes,
wherein the lipid membranes comprise
1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; and an aqueous medium in which the
bupivacaine encapsulated MVLs are suspended; wherein erucic acid
concentration in the composition is about 23 .mu.g/mL or less
(e.g., about 22.7 .mu.g/mL) after the composition is stored at
25.degree. C. for one month. In some embodiments, the composition
has an initial pH of about 7.4. In some further embodiments, the
erucic acid concentration in the composition is about 38 .mu.g/mL
or less (e.g., about 37.3 .mu.g/mL) after the composition is stored
at 25.degree. C. for two months. In some such embodiments, the
composition has a pH of about 7.1 after the composition is stored
at 25.degree. C. for two months. In some further embodiments, the
erucic acid concentration in the composition is about 54 .mu.g/mL
or less (e.g., about 53.0 .mu.g/mL) after the composition is stored
at 25.degree. C. for three months. In some such embodiments, the
composition has a pH of about 6.9 after the composition is stored
at 25.degree. C. for three months. In some further embodiments, the
erucic acid concentration in the composition is about 100 .mu.g/mL
or less (e.g., about 98.7 .mu.g/mL) after the composition is stored
at 25.degree. C. for six months. In some further embodiments, the
composition has a pH of about 6.5 after the composition is stored
at 25.degree. C. for six months. In some further embodiments, the
lipid membranes further comprise cholesterol and tricaprylin.
[0127] In some embodiments, the erucic acid concentration in the
composition of bupivacaine MVLs is at least about 1%, 2%, 3%, 4%,
5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15% less than the
erucic acid concentration in the Exparel.RTM. product currently on
the market, under the same incubation conditions. In some such
embodiments, the incubation condition is at 25.degree. for 1 month,
2 months, 3 months, or 6 months.
[0128] Some additional aspect of the present disclosure relates to
a composition of bupivacaine encapsulated multivesicular liposomes
(MVLs), comprising: bupivacaine residing inside a plurality of
internal aqueous chambers of the MVLs separated by lipid membranes,
wherein the lipid membranes comprise
1,2-dierucoylphosphatidylcholine (DEPC),
1,2-dipalmitoyl-sn-glycero-3 phospho-rac-(1-glycerol) (DPPG), and
at least one neutral lipid; and an aqueous medium in which the
bupivacaine encapsulated MVLs are suspended; wherein the internal
pH of the bupivacaine encapsulated MVLs is about 5.50. In some
embodiments of the composition described herein, the internal
lysine concentration of the bupivacaine encapsulated MVLs
composition is about 0.030 mg/mL to about 0.032 mg/mL. In some
further embodiments, the internal lysine concentration of the
bupivacaine encapsulated MVLs composition is about 0.031 mg/mL. In
some embodiments of the composition described herein, the internal
dextrose concentration of the bupivacaine encapsulated MVLs
composition is about 1.25 mg/mL to about 1.32 mg/mL. In some
further embodiments, the internal dextrose concentration of the
bupivacaine encapsulated MVLs composition is about 1.29 mg/mL. In
some further embodiments, the lipid membranes further comprise
cholesterol and tricaprylin. In some further embodiments, the
internal lysine or dextrose concentration are measured when the
bupivacaine MVLs are in an aqueous suspension having % PPV from
about 36% to about 38% (e.g., about 36.5%).
[0129] In some embodiments of the composition described herein, the
internal lysine concentration in the bupivacaine MVLs is at least
about 5%, 10%, 15%, 20%, 25%, or 30% more than the encapsulated
lysine concentration in the Exparel.RTM. product currently on the
market. In some such embodiments, the small change in lysine
concentration also results in the increase of the internal pH of
the bupivacaine MVL particles of about 5.50, as compared to the
internal pH of about 5.34 in the Exparel.RTM. product currently on
the market. In some such embodiments, the increase of the internal
pH is characterized by the decrease in [H.sup.+] concentration
(i.e., pH=-log [H.sup.+]). In some embodiments, the decrease in
[H.sup.+] concentration in the internal aqueous chambers of the
bupivacaine MVLs is at least about 5%, 10%, 15%, 20%, 25% or 30%.
In some further embodiments, the internal dextrose concentration in
the bupivacaine MVLs is at least about 2%, 5%, 7.5%, 10%, 12.5%,
15%, 17.5% or 20% more than the encapsulated dextrose concentration
in the Exparel.RTM. currently on the market.
[0130] In some further embodiments, the composition of bupivacaine
encapsulated MVLs may have a volume of 10 mL or 20 mL for a single
dose administration. In some embodiments, the percent packed
particle volume (% PPV) of the composition of bupivacaine
encapsulated MVLs is about 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%,
40%, 41%, 42%, 43% or 44%. In some such embodiments, the
concentration of the bupivacaine in the composition is from about
12.6 mg/mL to about 17 mg/mL. In one embodiment, the concentration
of the bupivacaine in the composition is about 13.3 mg/mL. In
further embodiments, the composition comprises less than 5%, 4%,
3%, 2% or 1% unencapsulated bupivacaine, wherein the amount of
unencapsulated bupivacaine is calculate based on the total weight
of the bupivacaine in the composition. In some embodiments, the
d.sub.50 of the multivesicular liposomes in the composition is
about 24 .mu.m to about 31 .mu.m. In one embodiment, the d.sub.50
of the multivesicular liposomes in the composition is about 27
.mu.m.
Methods of Administration
[0131] Some embodiments of the present application are related to
methods for treating, ameliorating pain comprising administering a
pharmaceutical composition comprising bupivacaine MVLs, as
described herein, to a subject in need thereof. In some further
embodiments, the pain is post surgical pain.
[0132] In some embodiments of the methods described herein, the
administration is parenteral. In some further embodiments, the
parenteral administration may be selected from the group consisting
of subcutaneous injection, tissue injection, intramuscular
injection, intraarticular, spinal injection, intraocular injection,
epidural injection, intrathecal injection, intraotic injection,
perineural injection, and combinations thereof. In particular
embodiments, the parenteral administration is subcutaneous
injection or tissue injection. In some further embodiments, the
instant pharmaceutical compositions can be administered by bolus
injection, e.g., subcutaneous bolus injection, intramuscular bolus
injection, intradermal bolus injection and the like. In one
embodiment, the administration is via local infiltration to a
surgical site to provide local analgesia. In another embodiment,
the administration is via interscalene brachial plexus nerve block
or femoral nerve block to provide regional analgesia.
[0133] Administration of the instant bupivacaine MVL composition
may be accomplished using standard methods and devices, e.g., pens,
injector systems, needle and syringe, a subcutaneous injection port
delivery system, catheters, and the like. The administration of the
bupivacaine MVLs composition may be used in conjunction with
Pacira's handheld cryoanalgesia device.
Pharmaceutical Compositions
[0134] In some embodiments, the composition comprising bupivacaine
MVLs is a pharmaceutical formulation includes a pharmaceutically
acceptable carrier. Effective injectable bupivacaine MVLs
compositions is in a liquid suspension form. Such injectable
suspension compositions require a liquid suspending medium, with or
without adjuvants, as a vehicle. The suspending medium can be, for
example, aqueous solutions of sodium chloride (i.e., saline
solution), dextrose, sucrose, polyvinylpyrrolidone, polyethylene
glycol, a pH modifying agent described herein, or combinations of
the above. In some embodiments, the suspending medium of
bupivacaine MVLs is a saline solution, optionally contain a
tonicity agent such as dextrose and/or a pH modifying agent such as
lysine.
[0135] Suitable physiologically acceptable storage solution
components are used to keep the compound suspended in suspension
compositions. The storage solution components can be chosen from
thickeners such as carboxymethylcellulose, polyvinylpyrrolidone,
gelatin and the alginates. Many surfactants are also useful as
suspending agents. The suspending medium could also contain
lecithin, alkylphenol polyethylene oxide adducts,
naphthalenesulfonates, alkylbenzenesulfonates, or the
polyoxyethylene sorbitan esters. In some embodiments, the
bupivacaine MVL composition is free or substantially free of any
additive of preservatives.
[0136] In any embodiments of the composition of bupivacaine
encapsulated MVLs described herein, the composition may be a
pharmaceutical composition suitable for human administration. In
further embodiments, the composition may be an aqueous suspension
of bupivacaine encapsulated MVL particles.
EXAMPLES
[0137] The following examples, including experiments and results
achieved, are provided for illustrative purposes only and are not
to be construed as limiting the present application.
Example 1: Lipid Hydrolysis Analysis Based on Erucic Acid Assay
[0138] In this example, the lipid stability of three batches (Batch
No. 1, 2 and 3 in Tables 1A and 1B) of bupivacaine MVLs aqueous
suspension prepared by the new process described herein and were
compared to ten reference samples of bupivacaine MVLs aqueous
suspension prepared by the current commercial process. DEPC
hydrolysis byproduct erucic acid was used as the marker to measure
the stability of the lipid membranes of the MVL particles. All the
samples were incubated at 25.degree. C. for 1 month, 2 months, 3
months and 6 months. The pH of the supernatant of each sample
(i.e., the external pH of the bupivacaine MVL composition) was also
tested at each time point and summarized in Table 1B. Erucic acid
was detected using HPLC and the erucic acid concentration in the
sample was calculated based on the HPLC peak area and the standard
curve.
TABLE-US-00001 TABLE 1A Erucic acid concentration in the
bupivacaine MVLs as a functional of time Erucic acid concentration
(.mu.g/mL) 1 month 2 months 3 months 6 months Batch 1 22 36 54 99 2
23 38 51 99 3 23 38 54 98 Average 22.7 37.3 53.0 98.7 % RSD 2.5 3.1
3.3 0.6 Reference samples Average n/a 38.7 55.4 113.1 % RSD n/a
24.3 15.0 4.2
TABLE-US-00002 TABLE 1B External pH of bupivacaine MVLs
compositions as a functional of time External pH 0 month 1 months 2
months 3 months 6 months Batch 1 7.4 7.2 7.1 6.9 6.5 2 7.4 7.1 7.1
6.9 6.5 3 7.3 7.1 7.1 6.9 6.5 Average 7.4 7.1 7.1 6.9 6.5 % RSD 0.8
0.8 0.0 0.0 0.0 Ref. Samples Average 7.1 7.1 6.9 6.8 6.5 % RSD 1.4
1.6 1.5 0.8 0.6
[0139] FIG. 3A is a line chart showing supernatant pH as a function
of incubation time of the bupivacaine-MVL compositions prepared by
the new process described herein as compared to those prepared by
the existing commercial process. It is known that during incubation
at 25.degree. C., the Exparel.RTM. product pH normally decreases
slightly. During the six months period, the pH of bupivacaine MVL
compositions prepared by the present process described herein
decreased 37% faster than those prepared by the existing process,
but still within the required 5.8-7.4 pH range.
[0140] FIG. 3B is a line chart showing erucic acid concentration as
a function of incubation time at 25.degree. C. of the
bupivacaine-MVL compositions prepared by the new process described
herein as compared to those prepared by the existing commercial
process. It was observed that the rate of lipid hydrolysis was 18%
lower in the bupivacaine-MVL compositions prepared by the new
process.
[0141] FIG. 3C is a line chart showing erucic acid concentration as
a function of supernatant pH at 25.degree. C. Typically, decreases
in pH can both catalyze, and be a consequence of lipid hydrolysis.
Therefore, a more rapid pH decline would normally be associated
with a more rapid increase in erucic acid concentration. However,
the slope for rate of change of erucic acid concentration as a
function of (decreasing) pH was actually flatter for the
bupivacaine-MVL compositions prepared by the new process as
compared to those prepared by the existing commercial process. The
improved lipid stability (as indicated by the erucic acid
concentration) observed in the bupivacaine MVLs prepared by the
presently described process was surprisingly unexpected.
Example 2: Measurement of Lysine and Dextrose Concentrations in
Bupivacaine MVLs
[0142] In this experiment, the lysine and dextrose concentration
were measured in three batches (Batch No. 1, 2 and 3 in Tables 2A
and 2B) of bupivacaine MVLs aqueous suspension prepared by the new
process described herein and compared to several reference samples
of bupivacaine MVLs aqueous suspension prepared by the current
commercial process.
TABLE-US-00003 TABLE 2A Lysine and dextrose concentrations in
bupivacaine MVL compositions Total Suspension MVL particles
Dextrose Lysine Dextrose Lysine Batch (mg/mL) (mg/mL) (mg/mL)
(mg/mL) 1 2.19 0.12 1.32 0.031 2 2.17 0.12 1.30 0.030 3 2.15 0.12
1.25 0.032 Average 2.17 0.12 1.29 0.031 Avg. Ref. Samples 1.86 0.11
1.14 0.024 Avg./Avg. Ref. 1.17 1.08 1.13 1.29 Samples
TABLE-US-00004 TABLE 2B External and internal pH in bupivacaine MVL
compositions Avg Time 0 Batch Internal pH Internal pH Sup pH 1 5.49
5.50 7.4 2 5.51 3 5.50 Ref. samples 5.38 7.1
[0143] It was observed that the total suspensions and bupivacaine
MVL particles prepared by the present process contained
approximately 17% and 13% more dextrose, respectively, than those
samples prepared by the existing commercial process. In addition,
the lysine concentration was 8% and 29% more in those samples
prepared by the present process. In addition, the internal and
external pH of the bupivacaine MVL compositions were also measured.
The higher internal pH of the bupivacaine MVL particles prepared by
the present process may be attributable to the higher lysine
concentration inside the MVL particles. As discussed above, the
slight increase in MVL internal pH may also contribute to the
stability of the lipid membranes.
* * * * *