FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
Provisional Specification
(See section 10 and rule 13)
A PROCESS FOR PRODUCING PARTICLES (NANOPARTICLES AND/OR
MICROPARTICLES) OF PHARMACOLOGICALLY ACTIVE AGENTS
USEFUL FOR PRODUCING THERAPEUTIC ACTIONS
PANACEA BIOTEC LIMITED
A company incorporated under the laws of India having their office at 104, SAMARPAN COMPLEX, NEW-LINK ROAD, CHAKALA, ANDHERI (E), MUMBAI 400099, MAHARASHTRA, INDIA
The following specification describes the invention

A PROCESS FOR PRODUCING PARTICLES (NANOPARTICLES AND/OR
MICROPARTICLES) OF PHARMACOLOGICALLY ACTIVE AGENTS
USEFUL FOR PRODUCING THERAPEUTIC ACTIONS
The present invention relates to a process for producing particles (nanoparticles and/or microparticles) of pharmacologically active agents to be administered to mammals to provide useful therapeutic actions as desired.
BACKGROUND OF THE INVENTION
Injectable particles (nanoparticles and/or microparticles) have been traditionally obtained by ultrasonication, high pressure homogenization and microfluidization techniques.
Tap Pharma's Lupron Depot® is a sustained release microcapsule of leuprolide prepared by the method wherein the drug containing inner aqueous phase along with a drug-retaining substance such as gelatin or basic amino acid is added to a polymer-containing solution (oil phase), followed by an emulsification procedure to give a w/o type emulsion. For this emulsification procedure, known methods are used, for example, the intermittent shaking method, the method using a mixer such as a propeller-shaped stirrer, a turbine shaped stirrer or the like, the colloidal mill method, the homogenizer method or the ultrasonification method. The thus prepared w/o emulsion is subjected to microencapsulation either by in-water drying or phase-separation method. The solvent is evaporated from the oil phase by employing any of the common methods, for example gradually reducing the pressure while stirring with a propeller-shaped stirrer or a magnetic stirrer, or by using rotary evaporator while adjusting the degree of vacuum. The microcapsules thus prepared were collected by centrifugation or filtration followed by freeze-drying to obtain powdery product, which according to the inventors of United States Patent No. 5480656, assigned to Takeda Chemical Industries Limited, provide satisfactorily spherical in shape microcapsules having an optimal size.
Abraxis Biosciences Abraxane® is an injectable nanoemulsion of paclitaxel and human serum albumin obtained by the same known techniques of ultrasonication (described in their patents United States Patent Nos. 5439686, 5498421, 5560933 and the corresponding W094/18954) or high speed and high pressure homogenization. (described in their patents United States Patent Nos. 5916596, 6096311 and the corresponding W098/14174 and WO99/00113). Stating that ultrasonication cannot be used on an industrial scale and that the microparticles obtained using ultrasonication technique has too high a mean particle size, which makes them unsuitable and unusable for administration to patients, the patentees formed nanoparticles of pharmacologically active agents by a solvent evaporation technique from an oil-in-water emulsion prepared under conditions of high shear forces in a high pressure homogenizer at a pressure in the range of about 3,000 up to 30,000 psi. According to the inventors these small nanoparticles (less than 200 nm diameter), are sterilized by sterile-filtration through a 0.22 micron filter since formulations which contain a significant amount of any protein (e.g., albumin) cannot be sterilized by conventional methods such as autoclaving, due to the heat coagulation of the protein. The sterile nanoparticles in the colloidal systems are further converted into powder form by removal of the water by lyophilization at a

suitable temperature-time profile. Thus in the embodiments in these and related patents in their family the final sterilized dispersion is lyophilized for 48 hours to form a cake like mass which can be easily reconstituted.
Janssen Pharma’s Risperdal Consta® is an intramuscular injectable microencapsulated risperidone for use in treatment of mental patients. Preferred process for making these microcapsules are described in United States Patent No. 5770231 and other related patents in its family wherein in their invention; the organic phase containing the active agent and the wall forming polymer or polymeric matrix material are pumped so that the two phases are simultaneously flowing through a static mixer, thereby forming an emulsion, which comprises microparticles containing the active agent encapsulated in the polymeric matrix material. The resulting microparticles ranging from submicron to millimeter diameters isolated from the quench liquid by using a sieve column are dried overnight using conventional drying techniques, collected and further size isolation done and lyophilized in a lyophilizer.
Thus as seen in all the above cases, the primary emulsification is conducted by conventional ultrasonication or high speed, high pressure homogenization techniques and also finally the obtained microparticles are lyophilized or freeze dried to provide the final product to be reconstituted before use.
DESCRIPTION OF THE INVENTION
In the present invention there is provided an aseptic method of preparing particles (nanoparticles and/or microparticles) by using spraying method instead of the conventionally used ultrasonication or high speed, high pressure homogenization techniques while preparing the primary emulsion, followed by hardening of the particles and sizing of the particles, which is then spray dried to obtain the particles instead of the widely used lyophilization technique.
The main objective of the present invention is therefore to provide an aseptic process for producing sterile spray dried powder of particles (nanoparticles and/or microparticles) of active agents and polymer or polymeric matrix materials which requires the application of sizing followed by spray drying for forming the final particles to be used after reconstitution.
Ultrasonication is not industrially feasible technique, homogenization does not provide highly uniform and high yield particles, and also there may be heat generation which would require cooling methods to be incorporated additionally and lyophilization is a costlier and complex, time consuming technique.
Spray drying is being used widely in formation of granules in the pharmaceutical industry; it can be done easily in a short time and at a lower cost to obtain high yields. In the present invention this spray drying method has been utilized to produce highly uniform, less variable and high yield of easily manufactured particles (nanoparticles and/or microparticles) comprising of the active agent and wall forming polymeric materials. Cryoprotectants may not be required in this technique, though it may be

understood that if needed it may be added for better product development, this spray drying technique is easy to validate, is reproducible and commercially viable and is an up scalable technique. Particles obtained by this technique are of uniform size, porosity and provide reproducible drug release from the particles over a desired period of time.
Even though spray drying may have been mentioned in some of the prior known patents mentioned above, for the preparation of nanoparticles or microcapsules, none of the prior art patents have actually demonstrated or exemplified in any of their embodiments a method of producing particles comprising active agents and polymers or wall forming agents using spraying and spray drying techniques during making of the primary emulsions and during the final preparation of the powder particles respectively, which is ready to be used by reconstitution. We have observed that just by using the conventional method of spray drying, highly uniform particles with high yield and less variability is not obtained. This requires process understanding, modifications, use of series of steps as described in this invention and use of additives as protectants in order to utilize spray drying as a technique to obtain the desired size particles (either nanoparticles and/or microparticles)
Pharmacologically or Physiologically active substances include, but are not limited to, physiologically active peptides, proteins, nucleotides, antigens, vaccines, antitumor agents, antibiotics, antipyretic agents, analgesics, anti-inflammatory agents, antitussive expectorants, sedatives, muscle relaxants, anti-epileptics, antiulcer agents, antidepressants, anti-allergic agents, cardiotonics, anti-arrhythmic agents, vasodilators, hypotensive diuretics, anti-diabetics, anti-hyperlipidemic agents, anti-coagulants, hemolytics, anti-tuberculosis agents, hormones, narcotic antagonists, bone resorption suppressors, osteogenesis promoters and angiogenesis inhibitors.
The present invention is well-described by the way of the following non-limiting examples in order to differentiate the present invention from that known in the art.
EXAMPLE 1

Ingredients Quantity w/w
Paclitaxel 120 mg
Alcohol (Absolute) 12 ml
Human serum albumin 1.2 g
Water for injection 300 ml
A. Paclitaxel was dissolved in alcohol to prepare a clear solution. The solution is
then filtered through 0.2 micron filter
B. Human serum albumin is dissolved in water for injection and filtered through 0.2
micron filter
C. Solution of step - A is added to solution of step - B under conventional low speed
stirring and then nanoparticles are generated by aerosol flow reactor method and
captured into 0.5 % polyvinyl alcohol solution

D. Alcohol is removed from the system under vaccum and the final solution is
subjected to tangential flow filtration / Asymmetric field flow fractionation to
obtain particles of desired size range
E. Particles thus obtained are mixed with sucrose solution and spray dried.
EXAMPLE 2

Ingredients Quantity w/w
Leuprolide acetate 3.75 mg
Purified gelatin 0.65 mg
Poly(lactic-co-glycolic acid) PLGA (75 : 25) 33.1 mg
D - mannitol 6.6 mg
A. Dissolve leuprolide acetate and purified gelatin in water. Also dissolve PLGA
(75: 25) in dichloromethane. Mix the two solutions under stirring.
B. The mixture is spray dried and collected into 0.5 % polyvinyl alcohol solution
under stirring. Stirring is continued for 3-6 hours with gradual increase in
temperature, resulting in hardening of particles.
C. The resulting particles are sized through vibro sifter to obtain desired particle size
range.
D. Resulting particles are suspended in a solution of mannitol and spray dried.
E. Spray dried particles are filled into vials, sealed and preserved.
EXAMPLE 3

Ingredients Quantity w/w
Risperidone 25 mg
Poly(lactic-co-glycolic acid) PLGA (50 : 50) 40.62 mg
Dichloromethane Lost in processing
D-mannitol lOmg
A. Dissolve risperidone and PLGA in dichloromethane and spray into a solution of
0.5 % polyvinyl alcohol in water under continuous stirring for 3-6 hours. The
stirring allows for partial hardening of particles.
B. The resulting particles are sized through vibro sifter to obtain desired particles
size range.
C. Resulting particles are spray dried.
D. The spray dried material is filled into vials, sealed and processed.

Example 4

Ingredients Quantity w/w
Poly(lactic-co-glycolic acid) PLGA polymer 16 meg
Human serum albumin 1.5 meg
Ethyl acetate 0.2 ml
Tetanus toxoid 1.5 meg
Poly vinyl alcohol 6.35 mg (does not remain in final product)
Water Does not remain in final product
Sugar 0.37 mg
A. Dissolve PLGA in ethyl acetate. Add Tetanus toxoid dispersed in 20 % human
serum albumin solution in water for injection to the above solution to form
primary emulsion under stirring.
B. Spray the solution of step A into solution of polyvinyl alcohol in water. Remove
the solvent by gradual stirring.
C. Size the particles on vibro sifter and re-disperse in sugar solution.
D. Spray dry the particles to obtain free flowing powder.
E. Coat tetanus toxoid on the surface of microparticles prepared in step D, fill into
vials and preserve.
Dated this 9th day of August, 2006

(Dr. MAHALAXMI ANDHERIA)
FOR PANACEA BIOTEC LIMITED