|Title of Invention||
METHOD OF STERILIZATION
|Abstract||A method of sterilization of active pharmaceutical ingredients characterized in that wet mass comprising micronised active ingredient along with pharmaceutically acceptable excipient and one or more vehicle thereof is subjected to a temperature ranging 100-140 degree/C for 3-30 mins at variable pressure units. The present invention further discloses the process for preparation of sterile pharmaceutical formulation.|
THE PATENT ACT 1970
(39 of 1970)
The Patents Rules, 2003
(Sec section 10 and rule!3)
1. TITLE OF THE INVÉNTION:
"Method of sterilization"
(a) NAME: CIPLA LTD.
(b)NATIONALITY: Indian Company incorporated under the Indian
Companies ACT, 1956
(c) ADDRESS: 289, Bellasis Road, Mumbai Central, Mumbai - 400 008,
3.PREAMBLE TO THE DESCRÏPTION
The following specification particularly describes the invention and the manner
in which it is to be performed.
Technical field of invention:
The present invention relates to an improved method of sterilization for steroids to be
used in formulations that are required to be sterile.
Background and prior art:
Sterilization is a process performed to ensure that thefe is complete freedom from
microbial contamination. Sterlisation is especially done for pharmaceutical formulations
which are to be directly introduced into the body and its cavities. Such formulations
explicitly include ophthalmic preparations, nasal preparations, ocular preparations,
injectables, transdermal patches, depot preparations and the like. Such sterilized
preparations involve two methods of preparations. First route is that the active ingrediënt
is sterilized and the formulation is prepared aseptically or the final is prepared, packed in
the desired container and then sterilized. The second route is known as terminal
Certain formulations such as respules or aqueous nasal preparations, ophthalmic
preparations and the like that involve steroids as the active ingrediënt are usually
prepared in the first method as described above. The most important reason being that
these formulations are usually packed in the container such as LDPE which are not
suitable for terminal Sterilization.
Several patents which disclose the method of Sterilization of the active ingrediënt. PT-A-
69652 discloses the cold Sterilization of micronized gluctfcorticosteroids using mixtures
of ethylene oxide and carbon dioxide, since, according to PT-A-69652, steroids in
powder form are not stable at temperarures above60 C. Specific examples of
glucorticosteroids are prednacindone, budesonide, dexamethasone and prednisolone, and
salts, esters and fluoro derivatives thereof, including dexamethasone acetate,
dexamethasone phosphate, prednisolone pivalate and 9-alphafluoro prednisolone.
However, ethylene oxide is toxic and when it is used to sterilize glucocorticosteroids it
has been found that the residual amounts of the ethylene oxide contravene pharmaceutical
guidelines, which require very low levels of residual ethylene oxide. Accordingly this
method has been found to be unsuitable for producing therapeutically acceptable
glucocorticosteroids and formulations thereof.
US-A-3962430 discloses a method for the production of sterile isotonic solutions of
medicina! agents, which comprises adding the agent to a saturated solution of sodium
chloride in water at lOO C and then heating the mixture at 1OO-130 C. This method is not
suitable for suspensions of fine particles of steroids, which are intended for inhalation
because the water, and the heating and cooling involved, produce unfavorable changes in
the size of the particles. Indeed it can lead to the formation of bridges between the fine
particles producing large, hard aggregates, which will not deaggregate into the desired
fine particles upon administration.
A putative alternative is dry heat sterilization. According to the European Pharmacopoeia
(1996, pp. 283-4) a normal heat sterilization process runs at l80o C for 30 min or at a
minimum of!60°C for at least 2 hours. According to Pharmacopoeia Nordica (1964,
pp. 16) such. sterilization can be carried out at 140°C for 3 hours. However at the
temperatures of these processes glucocorticosteroids suffer significant degradation and
Are subject to changes in their surface structure.
Sterilization by P-or y-irradiation is also known. Indeed Illum andMoeller in Arch.
Pharm. Chemi. Sci., Ed. 2,1974, pp. 167-174 recommends the use of such irradiation to
sterilize glucocorticosteroids. However when such irradiation is used to sterilize certain
finely divided, e. g. micronized steroids such as glucocorticosteroids, they are
WO-A-96/09814 to Andaris Ltd. relates to spray-dried particles of a water-soluble
material with a mass median partiële size of l to l O, um. The aim of the invention is to
produce smooth and spherical particles for use in dry powder inhalers. The water-soluble
material is preferably a human protein or a fragment there of in natural or recombinant
forai, e. g. human serum albumin (HSA), alpha-1 antitrypsin or alcohol dehydrogenase.
Also combinations of an active material with a carrier were produced e. g. budesomde
and lactose. It is stated generally that the microparticles produced can be sterile without
teaching how this could or would be neither achieved or showing any proof thereof.
WO-A-96/32095 to Astra AB relates to a process for the preparation of respirable
particles by dissolving an inhalation compound in a solvent introducing the resulting
solution containing the inhalation compound in droplet form or as a Jet stream into an
anti-solvent which is miscible with the solvent and which is under agitation. Budesomde
with a mass median diameter (MMD) of less thanlO um is produced with the process.
There is no Information in WO-A-96/32095 about sterilization or sterile particles.
WQ-A.-92/U280 to Instytut Farmaceutyczny relates. to a method of obtaining, (22R).
diastereoisomer of budesonide by a condensation reactioin followed by crystallizing the
crude product of condensation from ethanol. The obtained 21-acetate of budesonide
(22R) is hydrolyzed and the product thus obtained is crystallized from ethyl acetate. The
content of (22S) diastereoisomer of budesomde isl% or les3- There is no informatión in
WO-92/11280 about sterilization or sterile particles.
A methods for sterilizing biological materials by irradiation over temparaure gradiënt is
discussed in US patent application No.20040033160 by MacPhee at al. US patent
application No. 20040022673 by Protic deals with sterilization process and apparatus
therefor. US patent Application No.20040001774 by Williams at al. (Johnson & Johnson)
discloses sterilization with temperature- controlled diffusion Path. A chemical vapor
sterilization process and system with heat pump operated vaporizer/condenser is
discussed in US patent application No.20040033161 by Kendall et al. (Johnson
&Johnson). High pressure sterilizing of sensitive active pfinciples, particularly peptides,
oligonucleotides and proteins are disclosed in US patent Application No 2003103863 by
Grislain et al.
We have also found that attempts at terminal sterilization of the pharmaceutical
formulations, especially suspensions, e. g. aqueous suspensions, of glucocorticosteroids
have all proved unsatisfactory. Such suspensions cannot normally be sterilized by sterile
filtration, as most of the particles of glucocorticosteroid will be retained on the filter. We
have also shown that moist heat sterilization, e.g. steam treatment of glass vials
containing the product, leads to an unacceptable change in partiële size.
Various aqueous suspensions of finely divided glucocorticosteroids are known, e.g. the
budesonide-containing product known as Pulmicort# nebulising suspension. (Pulmicort#
is a trademark of Astra AB of Sweden). Similar formulations of fluticasone propionate
are known from WO-A-95/31964.
WO 99/25359 discloses a process for the sterilization of a glucocorticosteroid which
process comprises heat-treating the glucocorticosteroid in the form of a powder at a
temperature of from 100 to!30°C. Although it has been seen that by this method the
formulation shows a considerable rise in impurity levels on stability.
Therefore, there was a need for a new process of sterilization for steroids, which can then
be used in preparation of sterilized formulation.
Object of the invention:
The present invention therefore aims to provide an improved method of sterilization of
steroids involving mixing the steroid along with a surfactant and a vehicle and forming a
Another object of this invention is to provide a method of heat treating this wet mass and
at a particular temperarure-time profile and subsequently sterilizing the said wet mass.
It is yet another object of this invention to provide a sterilized wet mass which comprises
of the active ingrediënt selected from steroids and such other drugs of this class without
degradation of the active ingrediënt.
The present invention also aims at providing the use of this sterile wet mass, which can
be used in preparations, or formulations, which are required. to be sterile but cannot be
Summary of the invention:
The present invention comprises of a method of steriliza.tion of active pharmaceutical
molecules, that are susceptible to high temperatures; the said method involving forming a
wet mass of the active ingrediënt along with one or more pharmaceutically suitable
excipient and one or more vehicle thereof; the said sterillized mass containinj the
sterilized active ingrediënt thereof and the use of this sterillized mass in preparation of
formulations that are required to be sterile.
Description of Drawing:
Figure l indicates a diagrammatic representation of the process of sterilization. The
pressure vessel (2) contains the wet mass (3) for sterilization xhe pressure vessel (2) is
placed in an Autoclave (1). The wet mass (3) after being sterilized may be transferred to
the bulk solution (not shown in the figure) through the product outlet (4), which is
connected to the vessel containing bulk solution. The pressie vessel (2) is also provided
with air filter housing (5) for release of steam. The pressurt vessel (2) is further provided
with a product filter with housing (6), which may be neces,sary in Order to transfer some
bulk solution to the base solution in order to remove the remaining quantity of base
solution when the pressure in the pressure vessel (2) is low Both the filters (5) and (6)
are provided with 0.22 microns filter in order to maintain stfenlity of the base solution.
The present invention describes the method of sterilization of the active pharmaceutical
ingredients, such as steroids that are susceptible to higher temperatures. The method
involves introducing the said active ingrediënt into the pressure vessel or any other sealed
container along with one or more excipient and vehicle. The pressure vessel is fitted with
a hydrophobic vent filter and a hydrophobic cartridge filter. The sterilization is then done
at temperatures ranging from 100-140°C for 3- 30 mins at varying pressure units.
Preferable combinations for temperature-time-pressures are as foJlows:
A. 121oCf or 20 minsa t l5psi.
B. 132°C for 3 mins at 27 psi.
C. 115°C for 30 minutes at 10 psi.
The vessel used for sterilization is a conventional vessel fitted with the attachments such
as a vent filter, cartridge filter and the like, commonly known in the art.
The sterilization of the wet mass when used in formulations results in preparations with
reduced impurities as compared to preparations in which the API was sterilized by other
methods such as Dry heat sterilization, Gamma-radiation sterilization and simply moist
heat sterilization. This is because these molecules are highly susceptible to temperatures
above 60°C. And the sterilization is usually done at temperatures above 100°C. A
comparative impurity profile is as follows:
Impurity Non- F-radiation Dry Heat Sterilisation Moist
(%) sterile Heat
10 15 25 180°C/ 180°C/ 180°C/ 121/3
Kgy Kgy Kgy lOmin 20min 30mins 0
s s mins
Predisolone ND ND ND ND ND ND ND ND
D-Homo 0.06 0.07 0.06 0.286 0.06 0.06 0.06 0.05
Desonide 0.10 0.11 0.09 0.044 0.10 0.1 0.09 0.09
Predisolone- 0.02 0.15 0.21 0.062 0.05 0.07 0.07 0.04
21-Dehydro ND 0.10 0.12 0.284 0.07 0.09 0.10 ND
Epimers I and
1,2- 0.11 0.12 0.10 0.112 0.11 0.11 0.11 0.16
rs I and II
Single 0.04 0,21 0.27 0.182 0.19 0.23 0.26 0.05
Total 0.37 1.21 1.42 1.298 0.9 1.03 1.12 0.5
The steroids which may be used in the present invention include but are not limited to
betamethasone, fluticasone (e. g. as propionate), budesonide, tipredane, dexamethasone,
beclomethasone (e. g. as dipropionate), prednisolone, fluocinolone, triamcinolone (e. g.
as acetonide), momethasone (e. g. asfuroate), rofleponide (e. g. as palmitate),
flumethasone, flunisolide, ciclesonide, deflazacort, cortivazol,16a, 17a-butylidenedioxy-
6a, 9a-difluoro-ll ss, 21-dihydroxy-pregna-l,4-diene3,20-dione;6a, 9a-difluoro-ll ss-
hydroxy-16a, 17a-butylidenedioxy-17ss-methylthio- androsta-4-ene-3-one; 16a, 17a-
butylidenedioxy-6a, 9a-difluoro-11 ss-hydroxy-3-oxo- androsta-1,4-diene-17p-
carbothioic acid S-methyl ester; methyl9a-chloro-6a-fluoro-l l ss- hydroxy-16oc-methyl-
3-oxo-17a-propionyloxy-androsta-l} 4-diene-17a-carboxylate; 6a,9a-difluoro-ll ss-
hydroxy-16a-methyI-3-oxo-17a-propionyloxy-androsta-l,4-diene- 17p-carbothioic acid-
(2-oxo-tetrahydrofuran-3-yl) ester; optionally in their pure isomeric forms (where such
forms exist) and/or in the form of their esters, acetals or salts, where applicable. The
preferred steroids are selected from budesonide, fluticasone, triamcinolone, mometasone,
prednisolone, their salts, solvates, racemic mixtures, enantiomers, prodrugs or isomers
thereof. for use in preparations where the drug must reach the small cavities, such as the
bronchi, the cornea, and such other minute cavities, the active pharmaceutical ingrediënt
may be micronised before sterilization, with the preferred partiële size being d90 less
than 10 microns and more preferably d90 less than 5 microns.
The said excipient may be selected from surfactants which includes polyoxyethylene
esters of sorbitol anhydrides (tweens), the same compounds without the hydrophilic
oxyethylene groups (spans), higher molecuïar weight polyethylene glycols, and
molecular combinations of polyoxyethylene and polyoxypropylenes. The preferred
surfactants are tweens or a combination of tweens and spans. Optionally viscosity
building agents such as sodium carboxy methyl cellulose, polyvinyl alcohol may be used
instead of surfactants.
The said vehicle is water selected from purified water, water for injection or distilled
water, preferably of water for injection grade. The water does not contain any solute,
including any ions, present in the water.
The wet mass can be used in the preparation of the formulations which are required to be
sterile and cannot be sterilized terminally. Such preparations are nasal preparations such
as respules or the aqueous nasal preparations, ophthaJmic preparations and ocular
preparations. The invention is further illustrated with the following example.
Budesonjde respules 0.5 mg:
Sr.No 1 Ingredients 1 Quantity (%w/v)
r. Budesom'de (micronised) (—== «i~i Z__ J
2. Disodium edetate 0.01
3. ] Poiysorbate 80 0.016
4. Sodium chloride 0.9
5- Citric acid monohydrate q,s. to pH 4
6. Water for Injection 100 ml
Preparation of base solution:
1. Take budesonide along with polysorbate 80 and water for injection in the pressure
2. Sterilize the same by charging in an autoclave at 121 degrees for 30 minutes.
3. Transfer the sterilized pressure vessel to aseptic area.
Preparation of bulk suspension:
1. In water for injection cooled under nitrogen purging, add and dissolve sodium
chloride and disodium edetate under stirring.
2. Adjust the pH of suspension to 4.
3. Add the base solution from pre-sterilised pressure vessel to the bulk suspension
1. A method of sterilization of active pharmaceutical ingredients characterized in
that wet mass which comprises micronised active ingrediënt along with
pharmaceutically acceptable excipient and one or more vehicle thereof is
subjected to a temperature ranging 100-140°C for 3-30 mins at variable pressure
2. A method of sterilization as claimed in claim l, wherein said active
pharmaceutical ingrediënt are which highly susceptible to temperature above 60°C
are sterilized without effecting their stability.
3. A method of sterilization as claimed in claim l, wherein said active
pharmaceutical ingredients are selected trom the group of steroids and such other
drugs of this class.
4. A method of sterilization as claimed in claims l to 3S wherein said steroid are
selected from but are not limited to betamethasone, fluticasone (e.g. as
propionate), budesonide, tipredane, dexamethasone, beclomethasone (e.g. as
dipropionate), prednisolone, fluocinolone, triamcinolone (e.g. as acetonide),
momethasone (e. g. asfuroate), rofleponide (e.g. as palmitate), flumethasone,
flunisolide, ciclesonide, deflazacort, cortivazol,16a, 17a-butylidenedioxy-6a, 9a-
difluoro-11 ss, 21-dihydroxy-pregna-l,4-diene3,20-dione;6a, 9a-difluoro-ll ss-
hydroxy-16a, 17a-butylidenedioxy-17ss-methylthio- androsta-4-ene-3-one; 16a,
17a-butylidenedioxy-6a, 9a-difluoro-11 ss-hydroxy-3 -oxo- androsta-1,4-diene-
17p-carbothioic acid S-methyl ester; methyl9a-chloro-6a-fluoro-ll ss- hydroxy-
16oc-methyl-3 -oxo-17a-propionyloxy-androsta-1, 4-diene-17a-carboxylate;
diene- 17p-carbothioic acid- (2-oxo-tetrahydrofuran-3-yl) ester; optionally in their
pure isomeric forms (where süch forms exist) and/or in the form of their esters,
acetals or salts.
5. A method of sterilization as claimed in claim l, wherein preferred steroids are
selected from budesonide, fluticasone, triamcinolone, mometasone, prednisolone,
their salts, solvates, racemic mixtures, enantiomers, prodrugs or isomers thereof.
6. A method of sterilization as claimed in claim l, wherein the preferred partiële size
of said micronised active pharmaceutical ingrediënt beïng d90 less than 10
microns, more preferably d9Ö less than 5 microns.
7. A method of sterilization as claimed in claim, l wherein said excipient may be
selected from surfactants which includes polyoxyethylene esters of sorbitol
anhydrides (tweens), the same compounds without the hydrophilic oxyethylene
groups (spans), higher molecular weight polyethylene glycols, and molecular
combinations of polyoxyethylene and polyoxypropylenes and optionally selected
from viscosity building agents such as sodium carboxy methyl cellulose,
polyvinyl alcohol viscosity building agents such as sodium carboxy methyl
cellulose, polyvinyl alcohol.
8. A method of sterilization as claimed in claim l and 7, wherein the preferred
surfactants are tweens or a combination of tweens and spans.
9. A method of sterilization as claimed in claim l, wherein said vehicle is water,
selected from purifled water, water for injection or distilled water, preferably
water for injection grade.
10. A method of sterilization as claimed in claim l, wherein the water is not saturated
with respect to any solute, including ions, present in the water.
11. A method of sterilization as claimed in any of the preceding claims wherein said
sterilization is conducted at 121°C for 20 mins at 15psi.
12. A method of sterilization as claimed in any of the preceding claims wherein said
sterilization is conducted at 115°C for 30 mins at l0psi.
13. A method of sterilization as claimed in any of the preceding claims wherein said
sterilization is conducted at 132°C for 3 mins at 27psi.
14. A process for making an aqueous sterile pharmaceutical formulation, the said
process comprises placing a wet mass comprising the steroid, an excipient and
water in a pressure vessel or any other sealed container which in turn is placed in
an autoclave, heat treating the wet mass to sterilize the steroid and directly
transferring the sterilized mass to the remaining bulk of the formulation.
|Indian Patent Application Number||313/MUM/2004|
|PG Journal Number||21/2012|
|Date of Filing||12-Mar-2004|
|Name of Patentee||CIPLA LIMITED|
|Applicant Address||289, BELLASIS ROAD, MUMBAI CENTRAL, MUMBAI-400008|
|PCT International Classification Number||A61L|
|PCT International Application Number||N/A|
|PCT International Filing date|