Note: Descriptions are shown in the official language in which they were submitted.
W O 94/08596 2 1 4 7 8 8 9 P ~ /GB93/02141
COMPOSITION BASED ON POLYOXYETHYLENE POLIOXYPROPYLENE
BLOCK COPOLYMERS AND CONTAINER ~NTAINING IT
The present invention relates to a stable pharm~ce~ltic~l formulation of a
polyoxypropylenelpolyoxyethylene block copolymer.
Certain surface-active polyoxypropylene/polyoxyethylene block copolymers have been
found to have beneficial effects in animal and human medicine. In parSicular, the
copolymers may be used for treating circulatory disorders alone or in combination with
other agents, such as fibrinolytic enzymes, anticoag~ ntc, free radical scavengers, anti-
infl~mm~tory agents, antibiotics, membrane stabilisers and/or perfusion media. These
uses are described in US Patent Nos. 3,641,240, 4,801,452, 4,873,083, 4,879,109,4,837,014, 4,897,263, 4,937,070, 4,997,644, 5,017,370, 5,028,599, 5,030,448,
5,032,394, 5,039,520, 5,041,288, 5,047,236, 5,064,643, 5,071,649, 5,078,995,
5,080,894, 5,089,260, 5,152,979, 5,182.106 and 5,198,211, all of which are
incorporated herein by reference.
The surface-active copolymers are effective in circulatory disorders where there is a
pathological hydrophobic interaction between cells and/or molecules. These interactions
are believed to be caused by 1) a higher than norrnal concentration of fibrinogen. 2)
generation of intravascular or local soluble fibrin, especially high molecular weight fibrin,
3) increased friction in the microv~cc~ tllre~ or 4) mechanical or chemical trauma to
blood components. These disorders cause an increase in pathological hydrophobic
interactions of blood co,nporlenls such as cells and molecules. It is believed that fibrin,
especi~lly soluble fibrin, incleases adhesion of cells to one another, markedly increases
friction in small blood vessels, and increases viscosity of the blood especially at low shear
rates. The effects of the surface-active copolymers are believed to be essen~ lylubrication effects because they reduce the friction caused by the adhesion.
CG,,Il,lc.cially available surface-active polyoxypropylene/polyoxyethylene blockcopolymers generally contain antioxidants . In particular, the preparation of poloxamer
188 that may be purchased from BASF (Pa,~ )pa"y, New Jersey, U.S.A.) contains BHT
(butylated hydroxytoluene). This antioxidant is not standardised for phal ..,~ce~lSic~l use.
In addition, antioxidants tend to be hydrophobic and insoluble in aqueous medium, and
some may also present toxicity problems This is clearly undesirable in an injectable
solution for use in medicine. It is therefore an object of the present invention to provide
WO 94/08596 PCr/GB93/02141
21478B9 2
an aqueous solution of a block copolymer that is substantially free of such antioxidants.
The absence of an antioxidant in solutions of block copolymers tends to result in their
oxidation and degradation. This leads to shorter chain molecules and by-products, such
as organic acids (for example acetic acid), resulting in a reduction in the pH of the
solution to 4 or even lower. It has further been observed that the lower the pH, the
faster and more extensive is the degradation of the copolymer. It is therefore an object
of the present invention to provide a stable aqueous solution of a block copolymer.
EP-A- 103290 describes aqueous pharmaceutical formulations of polyoxypropylene and
polyoxyethylene adjusted to a physiologically acceptable pH~ preferably from 6 to 8, by
addition of electrolytes and buffers. It does not however describe a pharmaceutical
formulation of a block copolymer of polvoxypropylenelpolvoxyethylene and does not
describe or allude to any of the above-mentioned disadvantages associated with such a
polymer. Similarly, US Patent No. 4,938,961 describes an aqueous solution of
polypropylene glycol but makes no reference to solutions of a block copolymer ofpolyoxypropylene/polyoxyethylene.
It is a further object of the present invention to provide an aqueous solution of a block
copolymer of polyoxypropylene/polyoxyethylene that is suitable for injection. especially
intravenous injection.
The present invention accoldh-gly provides a sealed pharrn~ceu~ically acceptablecolllainer which contains in a vacuum or in an inert atmosphere a sterile aqueous
injectable solution of a block copolymer of formula (I):
HO(C2H4O)b(c3H6O)a(c~H4o)bH (I)
wherein a is an integer such that the hydrophobe represenled by (C,H O) has a
molecular weight of from 950 to 4000 Daltons, preferably about 1200 to 3500 Daltons,
and b is an integer such that the hydrophile portion leplese"~ed by (C~H40) constihltes
from 50% to 95% by weight of the copolymer, the solution being substantially free from
an antioxidant and being buffered at a pH from 5.5 to 6.5.
A pl ~r~llt;d block copolymer of formula (I) is wherein the molecular weight of the
WO 94/08596 21 4 7 8 8 9 PCr/GB93/02141
..
hydrophobe (C3H6O) is approximately 1750 Daltons and the total molecular weight of
the copolymer is approximately 8400 Daltons. A particular example of such a block
copolymer is that which is l erel I ed to as poloxamer 188 (BASF, Pal ~ip?an~, New Jersey,
U.S.A.). A discussion ofthe structure of poloxamers and poloxamine block copolymers
can be found in Schmolka, I.R., "A Review of Block Polymer Surf~ct~ntc", J. AM. OIL
CHEMISTS SOC., 54: 110-116 (1977), which is incorporated herein by reference.
Commercially available sources of poloxamer 188 are stated to have a molecular weight
of appl ~xhllately 8400 Daltons. In reality, the block copolymer is composed of
molecules having a molecular weight from less than 3000 Daltons to over '0,000
Daltons. The molecular diversity and distribution of molecules of commercial poloxamer
188 can be illustrated by broad primary and secondary peaks detected using gel
pelllleation chromatography, as described in WO 92/16484.
The high molecular weight components. i.e. the components having a molecular weight
greater than 15kDaltons, that are present in commercially available poloxamer 188
normally amount to 3%, by weight, of the block copolymer or even more. Such
significant arnounts may give rise to unwanted side-effects in the clinical application of
the block copolymer. In particular, these components have a longer elimin~tion phase
half life than the bulk of the block copolvmer and thus accum~ te in the plasma and
kidneys. In addition, these high molecular weight components may be responsible for
activation ofthe complement system. It is thus pler~lled that the block copolymer of use
with the present invention is free, at least to a substantial extent, i.e. Iess than 1%,
preferably 0.5% or 0.2%, by weight, of any molecules having a molecular weight greater
than 15kDaltons.
A standard measure of the molecular weight distribution of a polymer is its
polydispersity. This is referred to and described in W092/16484, the contents of which
are incorporated herein by reference. Briefly, a polydispersity of 1.0 is indicative of a
polymer in which all molecules have the same molecular wei_ht. A typical polymer may
have a polydispersity of 2 to 5. The block copolymer of polyoxypropylene/
polyoxyethylene of use with the present invention preferably has a polydispersity less
than 1.4, preferably 1.3 or 1.2 or even 1.1.
The surface-active block copolymer mav be formed by condens~tion of ethylene oxide
:; :
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21~7889 4
and propylene oxide at elevated temperature and pressure in the presence of a basic
catalyst. However, there is statistical variation in the number of monomer units which
co~-~b;ne to form a polymer chain in each copolymer. The molecular weights given are
approxi"lalions of the average weight of copolymer molecule in each preparation. A
more detailed discussion of the p-epa~ ~lion of these copolymers is found in U.S. Patent
No. 2,674,619, which is incorporated herein by reference. The preferred forms ofthe
block copolymer, that is the forms which are free from any significant amount ofmolecules having a molecular weight greater than 1 SkDaltons, or which have a
polydispersity of less than I .4, may be obtained by the process described in WO92/16484.
Certain commercially available block copolymers, such as poioxamer 188, may be
provided in a form containing an antioxidant. Prior to use with the present invention, the
antioxidant should be removed from the copolymer, for example, by filtration or by some
other means known in the art. Preferably, however, the block copolymer is obtained in a
form that is already substantially free from an antioxidant.
The amount of block copolymer contained within the aqueous injectable solution is
preferably from 135 to 165 mg/mL, especially about 150 mglmL (i.e. milligrams per
millilitre).
The pH ofthe aqueous injectable solution is preferably about 6.
The aqueous injectable solution is buffered at the desired pH using a buffering agent.
Examples of such buffering agents include citrate (for example sodium citrate/citric acid).
The conce"L~ alion of the buffering agent, in particular citrate buffering agent, should
preferably be from 0.005 to 0.05M, particularly about O.OlM.
Although a pharm~ce~ltically acceptable co-solvent may optionally be present in addition
to water, it is pre~e.led that the medium for the aqueous injectable solution is wholly or
substantially aqueous.
The aqueous injectable solution is preferably of such tonicitv with the blood serum of the
patient so as to avoid undesirable side effects. If the tonicitv of the aqueous injectable
solution needs to be increased, then a substantially isotonic solution may be obtained by
WO 94/08596 21 4 7 8 8 ~ PCI/GB93/02141
S
the inclusion of a pharm~ceutically acceptable agent that is capable of raising the tonicity
of the solution to the required level. Examples of such an agent are well known in the art
and include dextrose and sodium chloride and mixtures thereof.
The aqueous injectable solution may be provided in sterile form by filtration or by
autoclaving.
The formulation of the aqueous injectable solution and its filling into a pharrnaceutically
acceptable containers are preferably carried out in accordance with procedures known in
the art in which conditions are designed to minimise the oxygen in the formulation
solution or headspace.
Examples of a pharmaceutically acceptable container include plastic and glass containers,
such as vials, ampoules and bottles. The containers may optionally be coloured, such as
amber, to reduce the exposure of the aqueous injectable solution to UV light andpossible degradation. Alternatively, the containers may be colourless but packa_ed in
opaque cartons.
Preferably,the aqueous injectable solution is contained in an inert atmosphere which is
nitrogen.
The surface-active copolymer may be used in the treatment of circulatory disorders
which are caused by or which cause pathological hydrophobic interaction of bloodcomponents. Examples of such disorders include myocardial infarction, stroke, bowel or
other tissue infarctions, m~lign~ncies, adult respiratory distress syndrome (ARDS),
dicsemin~ted intravascular coagulation (DIC), diabetes, unstable angina pectoris,
hemolytic uremic syndrome, red cell fragmentation syndrome, heat stroke, retained fetus,
eclampsia, m~lign~nt hypertension, sickle cell disease, burns, crush injuries, fractures,
trauma producing shock, major surgery, sepsis, bacterial, parasitic, viral and riCIf,ottc
infections which promote activation of the co~ tion system, central nervous system
trauma, and during and immediately after anv major surgery.
The surface-active copolymer is also effective in increasing the collateral circulation to
und~m~oed tissues with compromised blood supply. Such tissues are frequently ~djacent
to areas of vascular occlusion. The mech~nicm appears to be reducino pathological
WO 94/08596 PCI/GB93/02141
2I~78`8`9- 6
hydrophobic interactions in small blood vessels. Circulatory disorders in which the
surface-active copolymers are effective include cerebral thrombosis, cerebral embolus,
myocardial infarction, unstable angina pectoris, transient cerebral ischemic attacks,
intermittent claudication of the legs, plastic and reconstructive surgery, balloon
angioplasty, peripheral vascular surgery, and orthopedic surgery, especially when using a
tourniquet. The copolymer may also be used for the preservation of organs for
transplantation .
The aqueous injectable solution of the block copolymer may be administered to the
patient by bolus injection or preferably by infusion. A convenient site for a~ministration
will normally be a peripheral vein. A bolus injection usua]ly comprises atlrninictration
over a two minute period. Infusions are normally carried out with the solution contained
within an infusion bag or bottle or within an electrically operated infusion pump. The
solution may be delivered from the infusion bag or bottle to the patient by gravitv feed or
by the use of the infusion pump.
An effective amount of the block copolymer to treat a patient with a circulatory disorder
will of course depend on a number of factors including, for example, the age and weight
of the patient, the precise condition requiring treatment, the route of administration, and
will ultimately be at the discretion of the attendant physician. It is likely however that an
effective amount will generally be in the range of from 0.2 to 3.0 g/kg, preferably 1.5 to
2.5 g/kg bodyweight, a-lminictered to a patient over a period from 1 to 4~ hours.
The following examples are provided in illustration of the present invention:
Example I
For a 5000 litre batch size, the following formulation and m~nllfacturing procedure were
employed in which nitrogen protection was used throughout:-
wo 94/08sg6 ~1 4 7 8 8 9 PCr/Cllg3/02141
Per Batch
Poloxamer 188, NF' 750.00 kg
Sodium Chloride, USP 15.40 kg
Sodium Citrate (Dihydrate), USP11.90 kg
Citric Acid Anhydrous, USP 1.83 kg
Water for Injection, USP q.s
TOTAL 5000.0 litres
1. Collect approximately 4000 litres of preheated water for injection (70 -80 C)
into a suitable vessel (vessel No. 1). Collect an additional 1000 litres of preheated water
for injection (70 -80 C) into a second vessel (vessel No. ').
2. Purge water in both vessels with filtered nitrogen gas. Cool to room temperature
while continually purging with filtered nitrogen gas.
3. Dissolve the citric acid~ sodium citrate and sodium chloride in the nitrogen
purged water in vessel No. 1. Continue purging with filtered nitrogen gas.
4. Blanket the headspace with filtered nitrogen gas and discontinue nitrogen
purging. Slowly add the block copolymer to the solution. Mix until dissolved. Note:
Continue to blanket the headspace with filtered nitrogen gas while mixing.
5. Add sufficient water for injection, previously nitrogen purged (from vessel No. 2)
to bring the batch to final volume and mix.
6. Filter solution through a "~e",b~ ~ne filter, 0.45 micrometers or equivalent, into a
suitable, clean, nitrogen-purged reservoir.
7. Under clean conditions, fill approxil"ately 500 mL of solution into previously
WO 94/08596 PCI/GB93/02141
21 ~ 78~ 9 8
washed, 650-mL Type 1 flint glass bottles.
8. Under clean conditions, apply suitable closures to bottles without inse. ling them
into the bottles.
9. Apply vacuum to he~rlcpace and insert closures into filled bottles.
10. Apply overseals.
11. Terminally sterilize product.
12. Cool product to room temperature, then mix until uniform.
13. Store bottles in individual cardboard cartons to protect the product from light.
On a mL basis, the amounts of the above components in the formulation are as follows:-
Per mL
Poloxamer 188, NFI 150.0 mg
Sodium Chloride, USP 3.08 mg
Sodium Citrate (Dihydrate), USP2.38 mg
Citric Acid Anhydrous, USP 0.366mg
Water for Injection, USP q.s.
TOTAL 1.0 mL
The aqueous injectable solution provided in this way is a clear, colourless solution, freeof particulate matter, haze or swirl and is stable, as evidenced by the following data:
IC. - glessthanO.2%of '- '~~ havinga ~e '- weightgreaterthan I~kDaltonsand
provided in this form.
W O 94/08596 21 ~ 7 8 8 9 PC~r/G B93/02141
Degradation Products
Poloxamer 188 (PPM)
Stora~e pH D Mw Mn %1. s. ach act pro met form
At Storage 5.8 1.21 5718.0 4713.0 99 3 25 <1 21 <1 2
W: 7 days 5.8 -----NOT DONE ----- 98 4 25 3 24 <1 2
14 days 5 8 ----- N O T DONE ----- 99 l 20 3 20 <1 2
Fluor: 7 days 5.8 -----NOT D O N E----- 100 3 24 7 25 <1
14 days 5.8 -----NOT D O N E----- 9 9 0 1 9 7 19 <1
50C 1 month 5.8 1.24 5438.0 4408 0 101.6 22 <1 19 <I 4
4 months 5.8 1.24 5418.0 4369 0 98.3 33 1 29 cl 6
40C 4 months 5.7 1.26 5437.0 4326.0 98 6 36 <1 33 <I 5
30C 4 months 5.6 1.25 5429.0 4354 0 99.2 35 1 33 <1 5
PPM: Parts Per Million ach: acet~ld~hyde
D: polydispc.~iLy (Mw/Mn) act: acetone
NtA: Not Available pro: propionaldehyde
Fluor: Fluoroscent met: meth~nol
l.s.: labelled strength forrn: formaldehyde
Example 2
The procedure of Example 1 was repeated for a 200 litre batch size using the following
formulation and collecting 160 litres in vessel N o.1 and 40 litres in vessel No.2:
WO 94/08596 PCl/GB93/02141
214~88~ l
Poloxamer 188, NF' 30.00 kg
Sodium Chloride, USP 0.616kg
Sodium Citrate (Dihydrate), USP 0.476kg
Citric Acid Anhydrous, USP 0.0732kg
Water for Injection, USP qs
TOTAL 200.0 litres
The resl~lting aqueous injectable solution was similar in ph~sical appearance as that
provided by Example 1. The following stability data were obtained.
Degradation Products
Poloxamer 188 (PPM)
Storage pH D Mw Mln %l. s. ach act pro met form
At Storage 5.8 1.24 5550.0 4482.099.8 32 <1 11.0 <1 <1
W: 7 days 5.7 1.28 5764.5 4509.599.7 23 4 24 1 3
14 days 5.9 1.29 5789.0 4498.098.8 22 7 23
Fluor: 7 days 5.8 1.29 5852.0 4535.599.2 24 9 23 2 3
14 days 5.9 1.29 5873.0 4545.598.1 25 12 2S 2 4
50C 1 month 5.8 1.26 5591.5 4428.0104.8 33 1 29 <1 7
2months 5.7 1.35 5411.0 3996.0101.7 35 1 28 2 10
40C 3 months 5.8 1.25 5414.0 4327.099.6 30 <1 22 <1 8
30C 3 months 5.9 1.26 5328.0 4228.098.6 22 <I 19 <1 4
WO 94/08596 21 ~ 7 8 8 9 PCI/GB93/02141
11
PPM: Parts Per Million ach: acetaldehyde
D: polydispersity (Mw/Mn) act: acetone
N/A: Not Available pro: propionaldehyde
Fluor: Fluoroscent met: methanol
l.s.: labelled strength form: formaldehyde
