DESC:FORM 2
THE PATENTS ACT 1970
(39 of 1970)
AND
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule13)
1. TITLE OF THE INVENTION:

“PHARMACEUTICAL COMPOSITIONS OF POLYMERIC NANOPARTICLES”

2. APPLICANT:

(a) NAME: CIPLA LIMITED

(b)NATIONALITY: Indian Company incorporated under the
Companies Act, 1956

(c) ADDRESS: Mumbai Central, Mumbai – 400 008, Maharashtra, India.

3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be formed.

FIELD OF INVENTION:
The present invention relates to pharmaceutical compositions comprising polymeric nanoparticles of anticancer drugs, a process for preparing such pharmaceutical compositions and their use in the treatment of tumours, especially brain tumours.

BACKGROUND AND PRIOR ART:
Glioblastoma multiforme (GBM) and anaplastic astrocytomas (AA) are the most common form of primary brain tumours occurring at an incidence rate of 14 cases per 1,00,000 adults in United States of America. Glioblastoma multiforme is the most dangerous type of brain tumour that remains poorly prognosed despite the progress in chemotherapy and radiation.
Currently, the treatment of Glioblastoma multiforme is carried out by administering oral alkylating agents and nitrosoureas, especially by administration of temozolomide and bevacizumab.

Further, surgical resection, concomitant administration of chemotherapy and radiation, use of heavy particle radiations, intracerebral and intraventricular injections of anticancer agents, convection enhanced delivery involving the administration of the chemotherapeutic agent by causing disruption of the BBB are some of the other approaches for treating brain tumours.

However, despite various advances in understanding the molecular biogenesis and makeup of the brain, treatment of the brain tumour remains dismal.

One of the major reasons for failure of chemotherapy in the treatment of brain tumours is the presence of the Blood Brain Barrier (BBB). The Blood Brain Barrier is composed of tight junctions formed due to the embracing of endothelial cells, pericytes and astrocytes together. These tight junctions allow the passage of few small sized particles, hydrophobic materials (only 2%) and agents that are required by the cells for their growth.

Further, factors like auto-protective nature of the brain (BBB and alignment of brain cells), genomic alterations occurring in tumour cells, efflux transporters on the barrier and properties of chemical agents used for treatment of brain tumours cause difficulty in the delivery of anticancer agents to the brain.
The anatomy of the tumour, resistance of the cells to apoptosis, cytotoxic drugs and radiotherapy makes the treatment of tumours extremely difficult.

Hence, the current approaches for the treatment of brain tumours include pharmacological approach and physiological approach. Physiological based approach involves disruption of BBB using osmotic agents and convection enhanced delivery (CED), whereas pharmacological approach includes modification of chemical structure of the drug by synthesizing a prodrug.

However; such approaches are disadvantageous as they may cause infections and the intrusion of foreign matter into the brain. Further, the anticancer drug may get cleared before it even reaches the cancer cells.

Further, one of the characteristics that distinguish anticancer agents is the frequency and severity of side effects at therapeutic doses. These side effects may be acute or chronic, self-limited, permanent, mild or potentially life threatening. Hence management of these side effects is of utmost importance because they affect the treatment, tolerability and overall quality of life. Common toxicities that may be encountered are haematological, gastrointestinal, skin and hair follicle toxicity, nervous system toxicity, local toxicity, metabolic abnormalities, hepatic toxicity, urinary tract toxicity, cardiac toxicity, pulmonary toxicity, gonadal toxicity etc.

Measures that can ameliorate the toxicities of anticancer drugs, include dose reduction, use of alternate drugs or their analogues, growth factors, and cytoprotective agents. However, employing any of these measures might affect the treatment and ultimately the therapeutic efficacy of the desired anticancer agent/s.

Further, anticancer drugs cannot greatly differentiate between cancerous and normal cells, leading to systemic toxicity and adverse effects. In addition, rapid elimination and widespread distribution into non targeted organs and tissues require the administration of the anticancer drug in large doses, which may not be economical as well as may exhibit nonspecific toxicity to such non targeted organs.
Nanoparticles of anticancer agents exhibit several advantages in the delivery of such agents by virtue of their small average particle size. Such nanoparticles are hydrophobic in nature and can cross the BBB to some extent.

Use of nanoparticles for cerebral cancer. Tumori 94, 271-277, Kreuter, J., Gelperina, S., 2008.

Influence of particle size on transport of methotrexate across blood brain barrier by polysorbate 80-coated polybutylcyanoacrylate nanoparticles. Int J Pharm 310, 213-219, Gao, K., Jiang, X., 2006.

Drug transport to brain with targeted nanoparticles. NeuroRx 2, 108-119, Olivier, J.C., 2005
Enhanced brain targeting of temozolomide in polysorbate-80 coated polybutylcyanoacrylate, nanoparticles, Xin-Hua Tian et al, International Journal of Nanomedicine 2011:6 445–452.

Composite Polylactic-Methacrylic Acid Copolymer Nanoparticles for the Delivery of Methotrexate, Bongani Sibeko et al, Journal of Drug Delivery, Volume 2012 (2012), Article ID 579629, 18 pages.

However, PLA-MAA nanoparticles of methotrexate prepared by double emulsion solvent evaporation technique as disclosed in this article are unstable and not homogenous which may ultimately affect the delivery of the anticancer drug to the site of action.

Although all the above prior arts disclose several strategies and formulations to overcome the difficulties in delivering the anticancer drugs for the treatment of brain tumours, there still exists a need to develop nanoparticulate pharmaceutical compositions of such anticancer drugs that alleviate these aforementioned problems as well as target such anticancer drugs at the specific site of action.

OBJECT OF THE INVENTION:
An object of the present invention is to provide pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs.

Another object of the present invention is to provide a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs optionally with one or more pharmaceutically acceptable excipients.

Another object of the present invention is to provide a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs exhibiting prolonged release.

Another object of the present invention is to provide a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs having improved surface area and solubility.

Another object of the present invention is to provide a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs having a reduced dose.

Another object of the present invention is to provide a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs to deliver said anticancer drugs to the target site of action as well as attempt to decrease or avoid the side effects.

Another object of the present invention is to provide a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs having enhanced Blood Brain Barrier passage.

Another object of the present invention is to provide a process for preparing a pharmaceutical composition comprising homogenous polymeric nanoparticles of anticancer drugs optionally with one or more pharmaceutically acceptable excipients.
Another object of the present invention is to provide the use in the treatment of brain tumours by administering a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs.
Another object of the present invention is to provide the use of a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs and optionally one or more pharmaceutically acceptable excipients in the manufacture of a medicament for treating brain tumours and any other tumour.

Another object of the present invention is to provide a method of treating brain tumours by administering a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs.

SUMMARY OF THE INVENTION:
According to an aspect of the present invention, there is provided a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs and optionally one or more pharmaceutically acceptable excipients.

According to another aspect of the invention, there is provided a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs to deliver said anticancer drugs to the target site of action as well as attempt to decrease or avoid the side effects.

According to another aspect of the invention, there is provided a process for the preparation of a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs and optionally one or more pharmaceutically acceptable excipients.

According to an aspect of the present invention, there is provided a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs and optionally one or more pharmaceutically acceptable excipients for use in the treatment of brain tumours.

According to an aspect of the present invention, there is provided the use of a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs and optionally one or more pharmaceutically acceptable excipients in the manufacture of a formulation for treating brain tumours.

According to an aspect of the invention, there is provided a method of treating brain tumours wherein the method comprises administering a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs and optionally one or more pharmaceutically acceptable excipients.

BRIEF DESCRIPTION OF THE DRAWINGS:
A) Studies were carried out on PLA nanoparticles of Methotrexate.

Figure 1: In vitro dissolution profile of Methotrexate (MTX) and PLA nanoparticles of Methotrexate (MTX- PLA- NP)
An initial burst release of Methotrexate from MTX- PLA- NP was seen with 30% of MTX being released in first few hours followed by slow release of drug for more than 48 hours. The release rates of MTX from MTX- PLA- NP were <15% at 2 hours, and <85% at 48 hours. Pure MTX was found to release from the dialysis bag within 2 hours. This study confirms the prolonged release of MTX- PLA- NP.

Figure 2: In vitro BBB permeation study of Methotrexate (MTX) and PLA nanoparticles of Methotrexate (MTX- PLA- NP)
The in vitro BBB passage model for the passage of MTX solution and MTX-PLA- NP was carried out at 24 hours and 48 hours. The readings were indicated in the form of permeability coefficients for the MTX-PLA-NP compositions and pure MTX. The highest passage was seen for MTX- PLA- NP as compared to MTX solution under each test condition (i. e monolayer as well as co-culture model). The passage for MTX-PLA-NP compared to MTX was enhanced even for co-culture model.

Figure 3: In vivo Pharmacokinetic study of Methotrexate (MTX) and PLA nanoparticles of Methotrexate (MTX- PLA- NP)
The pharmacokinetic study for MTX solution and MTX-PLA- NP through intravenous route was performed on male Wistar rats. Plasma profiles were obtained by determining the drug content present in plasma at predetermined time intervals. Area under curve (AUC0-48), for animals treated with MTX- PLA- NP was comparatively elevated. The in vitro release profile had good correlation to the release results in vivo obtained by measuring plasma drug concentration profile.
In vitro release profile demonstrated the release of drug for more than 48 hours. Similar release pattern was obtained in vivo. The in vivo drug release from nanoparticles continued for more than 48 hours and extended until 120 hours.

Figure 4: In vivo Bio-distribution study of Methotrexate (MTX) and PLA nanoparticles of Methotrexate (MTX- PLA- NP)
There were no detectable quantities in brain after administration of pure MTX solution which indicates poor passage of pure MTX through the BBB. Significant amount of drug was retained in brain after administration of MTX- PLA- NP.
B) Studies were carried out on PLGA as well as PLA nanoparticles of Temozolomide (TMZ- PLGA- NP).

Figure 5: In vitro BBB permeation study of Temozolomide (TMZ) and PLGA nanoparticles of Temozolomide (TMZ- PLGA- NP)
At 2 hours interval the permeation of TMZ loaded nanoparticles (in the co-culture model) was approximately 3 to 4 times higher as compared to pure TMZ. The % enhancement was approximately same at 24 hours and 48 hours of permeation.

Figure 6: Pharmacokinetic study of Temozolomide (TMZ) and PLGA nanoparticles of Temozolomide (TMZ - PLGA- NP)
Intravenous administration of TMZ loaded PLGA nanoparticles showed significant increase in mean plasma TMZ levels as compared to pure TMZ solution. A significant enhancement in plasma Area under curve (AUC) and Area Under Mean Curve (AUMC) was observed when TMZ was administered as polymeric nanoparticles as compared to pure TMZ solution.

Figure 7: Bio-distribution studies of Temozolomide (TMZ) and PLGA nanoparticles of Temozolomide (TMZ - PLGA- NP)
TMZ polymeric nanoparticles demonstrated a significant increase in brain concentration of TMZ as compared to pure TMZ solution. The enhancement in the TMZ concentration was found to be 2 to 3 times for TMZ in the brain as compared to the pure TMZ solution. Further there was a significant decrease in the distribution of TMZ to the other vital organs viz. lung, liver, kidney, spleen and heart when administered as polymeric nanoparticles of TMZ.
Figure 8: In vitro Blood Brain Barrier studies of Temozolomide (TMZ) and PLA nanoparticles of Temozolomide (TMZ-PLA-NP).

Polymeric nanoparticles of TMZ enhanced the permeation of TMZ through the BBB mainly in the co-culture model.

Figure 9: Pharmacokinetic study of Temozolomide (TMZ) and PLA nanoparticles of Temozolomide (TMZ - PLA- NP)
Enhancement in half-life (t1/2) and Area under the Curve (AUC) was seen for TMZ upon encapsulation (TMZ - PLA- NP). The increase in the mean residence time (MRT) demonstrated that prolonged circulating properties were imparted to TMZ in (TMZ - PLA- NP), thus prolonging the half-life and exhibited better bioavailability which eventually potentiates the action of TMZ.

Figure 10: Bio-distribution studies of Temozolomide (TMZ) and PLA nanoparticles of Temozolomide (TMZ - PLA- NP)
The distribution of TMZ in brain tissues was 4 times greater with surface modified nanoparticles as compared to pure TMZ. Further the distribution in highly perfused organs was significantly less and this can be attributed to surface modification of nanoparticles.
D) Studies were carried out on PLA nanoparticles of Temozolomide (TMZ- PLA- NP) and Folic Acid anchored nanoparticles of Temozolomide (TMZ – PLA – FA)

Figure 11: Pharmacokinetic study of Temozolomide (TMZ) and Folic Acid anchored nanoparticles of Temozolomide (TMZ – PLA – FA).
The results demonstrated prolonged plasma levels, reduced clearance, raised volume of distribution and increased mean residence time of TMZ upon administration of TMZ nanoparticles.

Figure 12: Bio-distribution studies of Temozolomide (TMZ) and Folic Acid anchored nanoparticles of Temozolomide (TMZ – PLA – FA).
The distribution of TMZ in brain tissues was 4 times greater with surface modified nanoparticles as compared to pure TMZ. Further the distribution in highly perfused organs was significantly less and this can be attributed to surface modification of nanoparticles.
DETAILED DESCRIPTION OF THE INVENTION:
The most efficient way for achieving optimal drug action, is to deliver the drug to the target site of action as well as attempt to decrease or avoid the side effects at the non-target sites.
Biocompatible and biodegradable polymeric nanostructured drug delivery systems greatly enhance the efficacy of many existing drugs and enable the construction of entirely new therapeutic approaches.

Nanoparticulate drug delivery systems have the ability to target therapeutic drugs to the site of action and reduce the toxicity or side effects. However, biodegradable polymeric nanoparticles specifically are preferred due to their non-toxic, non-immunogenic nature, enabling them to act as potential carriers.

Such nanoparticulate based polymeric drug delivery system are advantageous due to adjustable properties such as biodegradability, good biocompatibility and amphiphilic characteristics, controlled release, targeted delivery and therapeutic impact.

The polymeric biodegradable materials used in such nanoparticulate drug delivery system are natural or synthetic in origin and are degraded in vivo, either enzymatically or non-enzymatically or both, to produce biocompatible, toxicologically safe by-products which are further eliminated by the normal metabolic pathways.

The basic category of biomaterials used in drug delivery can be broadly classified as synthetic biodegradable polymers, semi-synthetic and natural, such as, but not limited to, the hydroxy acids (a family that comprises polylactic acid, polylacticcoglycolic acid), polyanhydrides, and others, and naturally occurring polymers, such as complex sugars (hyaluronan, chitosan), inorganics (hydroxyapatite), polycaprylactones, polymalic acids, polybutylcyanoacrylates, sugars, dextrans, human serum albumin, cellulose derivatives like hydroxypropylcellulose, hydroxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose polymers hydroxyethylcellulose, sodium carboxymethylcellulose, carboxymethylene and carboxymethylhydroxyethylcellulose; acrylics like acrylic acid, acrylamide, and maleic anhydride polymers, acacia, gum tragacanth, locust bean gum, guar gum, or karaya gum, agar, pectin, carrageenan, gelatin, casein, zein and alginates, polyvinyl alcohol, carboxypolymethylene, bentonite, magnesium aluminum silicate, polysaccharides, modified starch derivatives and copolymersor mixtures thereof.

Preferably, the polymers may be present in an amount ranging from about 0.1% to about 35% by weight of the composition.

Polylactic acid (PLA) and polylacticcoglycolicacid (PLGA) have been widely used to synthesize polymeric nanoparticles due to their biodegradability, non-immunogenic, non-toxic and biocompatibility properties.

PLA it is a polymer designed form lactic acid monomer which has its own mechanism of degradation within the body. The hydrophobic nature of the polymer is further suitable for transit of the nanoparticles through the fencing system of the brain.

PLGA is most widely used because of its long clinical experience, favourable degradation characteristics and possibilities for sustained drug delivery. Further, degradation of PLGA can be employed for obtaining sustained release of drugs at desirable doses by implantation without surgical procedures. Additionally, it is possible to alter the physical properties of the polymer-drug matrix by controlling the relevant parameters such as polymer molecular weight, ratio of lactide to glycolide and drug concentration to achieve a desired dosage and release interval depending upon the drug type.

According to the present invention, PLA and PLGA are the preferable polymers the have been employed in the pharmaceutical composition comprising polymeric nanoparticles.

Preferably, the pharmaceutical composition, according to the present invention, comprises PLA and PLGA nanoparticles of anticancer drugs.

According to one aspect of the present invention, the pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs have been engineered to have an affinity for target tissues through passive or active targeting mechanisms.

According to another aspect of the present invention, the pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs to deliver said anticancer drugs to the target site of action as well as attempt to decrease or avoid the side effects
According to another aspect of the present invention, the pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs exhibits prolonged release.

According to another aspect of the present invention, the pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs exhibits enhanced BBB passage.

According to another aspect of the present invention, the pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs having reduced dose.

Anticancer drugs, according to the present invention include, but are not limited to, alkylating agents, anti-metabolites, anti-microtubule agents, topoisomerase inhibitors or antitumor antibiotics, DNA linking agents, biological agents and bisphosphonates
Suitable alkylating agents, according to the present invention include, one or more, but are not limited to, nitrogen mustards, nitrosoureas, tetrazines, aziridines, and non-classical alkylating agents. Nitrogen mustards include mechlorethamine, cyclophosphamide, melphalan, chlorambucil, ifosfamide, busulfan. Nitrosoureas include N-Nitroso-N-methylurea, carmustine, lomustine, semustine, fotemustine, streptozotocin, dacarbazine,bendamustine, procarbazine, mitozolomide, temozolomide, thiotepa, mytomycin, diaziquone and the like or combinations thereof.

Suitable anti-metabolites, according to the present invention include, one or more, but are not limited to, methotrexate, pemetrexed, raltitrexed, asparaginase, fluorouracil, capecitabine, cytarabine, gemcitabine, decitabine, vidaza, fludarabine, nelarabine, cladribine, clofarabine, pentostatin, thioguanine, mercaptopurineand the like or combinations thereof.
Suitable anti-microtubule agents, according to the present invention include, one or more, but are not limited to vincristine, vinblastine, paclitaxel, docetaxel, etoposide, irinotecan, topotecan, vinorelbine and the like or combinations thereof.

Suitable topoisomerase inhibitors or antitumor antibiotics, according to the present invention include, one or more, but are not limited to actinomycin D, bleomycin, plicamycin, mitomycin, doxorubicin, daunorubicin, epirubicin, idarubicin, pirarubicin, aclarubicin, mitoxantrone, actinomycin, bleomycin and the like or combinations thereof.

Suitable DNA linking agents, according to the present invention include, one or more, but are not limited to, cisplatin, oxaliplatin, carboplatin and the like or combinations thereof.

Suitable biological agents, according to the present invention include, one or more, but are not limited to, alemtuzamab, BCG, bevacizumab, cetuximab, denosumab, erlotinib, gefitinib, imatinib, interferon, ipilimumab, lapatinib, panitumumab, rituximab, sunitinib, sorafenib, emsirolimus, trastuzumab and the like or combinations thereof.

Suitable bisphosphonates, according to the present invention include, one or more, but are not limited to, clodronate, ibandronic acid, pamidronate, zolendronic acid and the like or combinations thereof.

Suitable other anticancer drugs according to the present invention include, one or more, but are not limited to, anastrozole, bbiraterone, amifostine, bexarotene, bicalutamide, buserelin, cyproterone, degarelix, exemestane, flutamide, folinic acid, fulvestrant, goserelin, lanreotide, lenalidomide, letrozole, leuprorelin, medroxyprogesterone, megestrol, mesna, octreotide, stilboestrol, tamoxifen, thalidomide, tiptorelin and the like or combinations thereof.

In one embodiment, the pharmaceutical composition, according to the present invention, comprises PLA as well as PLGA nanoparticles of methotrexate. The term “methotrexate” is used in broad sense to include not only “methotrexate” per se but also its pharmaceutically acceptable derivatives thereof. Suitable derivatives include pharmaceutically acceptable salts, pharmaceutically acceptable solvates, pharmaceutically acceptable hydrates, pharmaceutically acceptable isomers, pharmaceutically acceptable esters, pharmaceutically acceptable anhydrates, pharmaceutically acceptable enantiomers, pharmaceutically acceptable polymorphs, pharmaceutically acceptable prodrugs, pharmaceutically acceptable tautomers and/or pharmaceutically acceptable complexes thereof.

Currently, methotrexate is indicated in the treatment of neoplastic diseases, psoriasis and Rheumatoid Arthritis including Polyarticular-Course Juvenile Rheumatoid Arthritis.

Specifically, methotrexate is employed for treating neoplastic diseases such as gestational choriocarcinoma, chorioadenomadestruens and hydatidiform mole. In acute lymphocytic leukemia, methotrexate is indicated in the prophylaxis of meningeal leukemia.

However, the inventors of the present invention have developed a pharmaceutical composition comprising PLA as well as PLGA nanoparticles of anticancer drug methotrexate, wherein, methotrexate is especially employed in the treatment of Glioblastoma multiforme (GBM) and anaplastic astrocytomas (AA).

The term “temozolomide” is used in broad sense to include not only “temozolomide” per se but also its pharmaceutically acceptable derivatives thereof. Suitable derivatives include pharmaceutically acceptable salts, pharmaceutically acceptable solvates, pharmaceutically acceptable hydrates, pharmaceutically acceptable isomers, pharmaceutically acceptable esters, pharmaceutically acceptable anhydrates, pharmaceutically acceptable enantiomers, pharmaceutically acceptable polymorphs, pharmaceutically acceptable prodrugs, pharmaceutically acceptable tautomers and/or pharmaceutically acceptable complexes thereof.

In another embodiment, the pharmaceutical composition, according to the present invention, comprises PLA as well as PLGA nanoparticles of temozolomide.

The pharmaceutical composition, according to the present invention, comprises PLA as well as PLGA nanoparticles of anticancer drugs, which can be administered by varying routes of administration such as, but not limited to, oral, parenteral (subcutaneous, intravenous, intramuscular, intradermal, intraperitoneal) or topical or localised(directly at the site)and the like.

The pharmaceutical composition, according to the present invention, comprises PLA as well as PLGA nanoparticles of anticancer drugs, which can be provided as, but not limited to, oral, parenteral or topical dosage forms, localised and the like.

The term "pharmaceutical composition" includes oral dosage forms, such as but not limited to, tablets, soft gelatin capsule, capsules (filled with powders, powders for reconstitution, pellets, beads, mini-tablets, pills, micro-pellets, small tablet units, MUPS, disintegrating tablets, dispersible tablets, granules, sprinkles, microspheres and multiparticulates), sachets (filled with powders, pellets, beads, mini-tablets, pills, micro-pellets, small tablet units, MUPS, disintegrating tablets, dispersible tablets, granules, sprinkles microspheres and multiparticulates) and sprinkles, however, other dosage forms such as liquid dosage forms (liquids, liquid dispersions, suspensions, solutions, emulsions, sprays, spot-on), microformulations, nanoformulations may also be envisaged under the ambit of the invention.

The term "pharmaceutical composition" includes parenteral dosage forms, such as liquid dosage forms (liquids, liquid dispersions, suspensions, solutions, emulsions, powders for reconstitution), gels, bolus, depots, implants (rods, capsules, rings) biodegradable or non-biodegradable microparticles/microspheres etc. may also be envisaged under the ambit of the invention.

The term "pharmaceutical composition" includes topical dosage forms, such as but not limited to, sprays, solutions, suspensions, ointments, drops, in-situ gel, aerosols, ointments, microspheres, creams, gels, patches, films and the like.

In one embodiment, the pharmaceutical composition of the present invention comprises PLA as well as PLGA nanoparticles of anticancer drugs, in the form of controlled release formulations, lyophilized formulations, delayed release formulations, timed release formulations, extended release formulations, pulsatile release formulations, and mixed immediate release and controlled release formulations.
Preferably, the pharmaceutical composition of the present invention comprising PLA as well as PLGA nanoparticles of anticancer drugs are provided in parenteral dosage forms.

Accordingly, the pharmaceutical composition of the present invention comprising PLA as well as PLGA nanoparticles of anticancer drugs is provided in a lyophilized parenteral dosage forms, these dosage forms are to be dissolved or reconstituted in a suitable solvent prior to administration.

Suitable solvents for reconstitution include, but are not limited to, purified water for injection, sterile saline solution, dextrose solution, Ringers solution and the like.

The inventors of the present invention have further observed that the PLA as well as PLGA nanoparticles exhibit enhanced penetration of the anticancer drugs to the site of action.

The present invention thus provides a pharmaceutical composition comprising PLA as well as PLGA nanoparticles of the anticancer drugs wherein such nanoparticles have an average particle size of less than or equal to about 2000 nm, preferably less than or equal to about 1000 nm, more preferably less than or equal to about 500 nm and most preferably less than or equal to about 250 nm.

The term average particle size as used herein refers to the average diameter of the particles.
Mostly all particles have a particle size of less than or equal to about 500 nm, preferably less than or equal to about 200 nm.

The term “particles” as used herein refers to an individual particle of the polymeric nanoparticle comprising anticancer drug(s), or the polymeric nanoparticles comprising particles of anticancer drug(s)or the polymeric nanoparticles comprising anticancer drug(s)compositions and/or mixtures thereof.

The particles of the present invention can be obtained by any of the process such as but not limited to milling, precipitation, homogenization, high pressure homogenization, spray-freeze drying, supercritical fluid technology, double emulsion-solvent evaporation, emulsion-solvent evaporation, emulsion-solvent diffusion, PRINT (Particle replication in non-wetting templates), thermal condensation, ultrasonication, interfacial polymerisation, spray drying and combinations thereof. Preferably, the particles of the present invention are prepared by the process of emulsion solvent evaporation with high pressure homogenization.

Accordingly, the process of solvent evaporation can comprise dissolving the anticancer drug and PLA/PLGA in suitable solvents followed by emulsification. The emulsion is subjected to high pressure homogenization and is further evaporated to produce the anticancer drug encapsulated PLA/PLGA nanoparticles.

Further, the drug encapsulated PLA/PLGA nanoparticles were optionally freeze dried.

Alternatively, the process of solvent evaporation can comprise dissolving the anticancer drug and PLA/PLGA in suitable solvents followed by emulsification and evaporation to produce nanodispersions of anticancer drugs which are further incubated with surface modifiers to form surface modified drug encapsulated PLA/PLGA nanoparticles.

In one embodiment, the anticancer drug encapsulated PLA/PLGA nanoparticles according to the present invention, obtained by the aforementioned processes may be formulated to obtain the desired dosage form.

Suitable excipients may be used for formulating the various desired dosage forms according to the present invention.

Surfactants, may be used in compositions of the invention which act as stabilizers to increase the stability of the composition. These are capable of stabilizing the particle thus inhibiting its aggregation and agglomerate formation. Further, they also enhance the BBB passage of the PLA/PLGA nanoparticles. Suitable amphoteric, non-ionic, cationic or anionic surfactants may be included in the pharmaceutical composition of the present invention.

Surfactants or emulsifiers that can be used in the compositions of the invention may comprise one or more of, but not limited to non-ionic triblock copolymers or poloxamers (Synperonics®, Lutrols®, Pluronics® and Kolliphor®), Polysorbates, Sodium tauroglycocholate, Sodium dodecyl sulfate (sodium lauryl sulfate), Lauryl dimethyl amine oxide, Docusate sodium, Cetyltrimethylammoniumbromide (CTAB), Polyethoxylated alcohols, Polyoxyethylenesorbitan, Octoxynol, N, N–dimethyldodecylamine–N–oxide, Hexadecyltrimethylammonium bromide, Polyoxyl 10 lauryl ether, Brij, Bile salts (sodium deoxycholate, sodium cholate), Polyoxyl castor oil, NonylphenolethoxylateCyclodextrins, Lecithin, Methylbenzethonium chloride. Carboxylates, Sulphonates, Petroleum sulphonates, alkylbenzenesulphonates, Naphthalenesulphonates, Olefin sulphonates, Alkyl sulphates, Sulphates, Sulphated natural oils & fats, Sulphated esters, Sulphated alkanolamides, Alkylphenols, ethoxylated& sulphated, Ethoxylated aliphatic alcohol, polyoxyethylene surfactants, carboxylic esters Polyethylene glycol esters, Anhydrosorbitol ester & it's ethoxylated derivatives, Glycol esters of fatty acids, Carboxylic amides, Monoalkanolamine condensates, Polyoxyethylene fatty acid amides, Quaternary ammonium salts, Amines with amide linkages, Polyoxyethylene alkyl & alicyclic amines, N,N,N,N tetrakis substituted ethylenediamines 2- alkyl 1- hydroxyethyl 2-imidazolines, N -coco 3-aminopropionic acid/ sodium salt, N-tallow 3 -iminodipropionate disodium salt, N-carboxymethyl n dimethyl n-9 octadecenyl ammonium hydroxide, n-cocoamidethyl n-hydroxyethylglycine sodium salt or mixtures thereof.

Preferably, the surfactants may be present in an amount ranging from about 0.01% to about 20% by weight of the composition.

Surface modifiers enhance the BBB passage of the PLA/PLGA nanoparticles. Such surface modifiers that may be used in compositions of the invention, include, but are not limited to, polyethylene glycols and its derivatives (N-hydroxysuccinimide activated PEG, succinimidyl ester of PEG propionic acid, succinimidyl ester of PEG butanoic acid, and succinimidyl ester of PEG alpha-methylbutanoate and the like or mixtures thereof), propylene gyclos, poloxamers, polysorbates, Cetyltrimethylammoniumbromide (CTAB) or mixtures thereof.

Ligands enhance the BBB passage of the PLA/PLGA nanoparticles as well as target the tumour cells. Such ligands that may be used in compositions of the invention, include, but are not limited to, folic acid, sugars, amines, antibodies, insulin, transferrin, diphtheria toxin or mixtures thereof in its own form or in conjugated form.

Suitable pH adjusting agents or buffering agents that may be used in the pharmaceutical composition, include, but are not limited to acidulants such as hydrochloric acid, acetic acid, citric acid, tartaric acid, propionic acid, sodium hydroxide, sodium phosphate, ammonia solution, triethanolamine, sodium borate, sodium carbonate, sodium acetate, potassium hydroxide and the like or combinations thereof.

Preferably, one or more buffering agent may be present in an amount ranging from about 0.1% to about 10% by weight of the total composition.

Suitable solvents/co-solvents, solubilizer or vehicles, that may be employed, in the pharmaceutical composition include, but are not limited to, dichloromethane, acetonitrile, ethyl acetate, acetone, propylene carbonate, water, glycerine, coconut fatty acid diethanolamide,medium and/or long chain fatty acids or glycerides, monoglycerides, diglycerides, triglycerides, structured triglycerides, soyabean oil, peanut oil, corn oil, corn oil mono glycerides, corn oil di glycerides, corn oil triglycerides, polyethylene glycol, caprylocaproylmacroglycerides, caproyl 90, propylene glycol, polyoxyethylenesorbitan fatty acid esters, polyoxyethylene castor oil derivatives, castor oil, cottonseed oil, olive oil, safflower oil, peppermint oil, coconut oil, palm seed oil, beeswax, oleic acid, methanol, ethanol, isopropyl alcohol, butanol, acetone, methylisobutyl ketone, methylethyl ketone or mixtures thereof.

Cryoprotectants for use in the invention, may comprise one or more of sucrose, lactose, sorbitol, dextrose, trehalose, mannose, glycine, ammonium acetate, poloxamers and the like or mixtures thereof.

Preferably, one or more cryoprotectants may be present in an amount ranging from about 0.5% to about 20% by weight of the total composition.

The present invention provides a process for preparing a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs, said process comprising the admixing of the nanoparticles of anticancer drugs with polymer and optionally with other pharmaceutically acceptable excipients followed by emulsification, homogenisation, solvent evaporation and lyophilisation and further processing it into the desired dosage form.

The present invention also provides a method of treating brain tumours by administering a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs.

The present invention also provides the use in the treatment of brain tumours by administering pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs.

It may be well acknowledged to a person skilled in the art that the said pharmaceutical composition, according to the present invention, may further comprise one or more active in particular other anticancer drugs, such as, but are not limited to, alkylating agents, anti-metabolites, anti-microtubule agents, topoisomerase inhibitors or antitumor antibiotics, DNA linking agents, biological agents and bisphosphonates.

The following examples are for the purpose of illustration of the invention only and is not intended in any way to limit the scope of the present invention.
Example:
A) Bolus Injection of PLA nanoparticles of Methotrexate
Sr. No Ingredients Quantity
1 PLA 75mg-100mg
2 Methotrexate 20-25 mg
3 Sodium tauroglycocholate 0.3-0.5% solution (15 to 20 ml)

Process:
1. Methotrexate and the polymer were solubilized in dichloromethane.
2. The solution obtained in step (1) was emulsified with sodium tauroglycocholate
3. The emulsion obtained in step (2) was subjected to high pressure homogenization.
4. The dichloromethane in the emulsion that is obtained in step (3) was evaporated and the residue was filled in the appropriate container and lyophilized and provided with a sterile saline solution for reconstitution.

B) Bolus Injection of PLA nanoparticles of Temozolamide
Sr. No Ingredients Quantity
1 PLA 75mg-100mg
2 Temozolamide 20-35 mg
3 Sodium tauroglycocholate 0.3-0.5% solution (15 to 20 ml)

4 PEG 0.5-1%
5 Sodium acetate buffer q. s.
Process:
1. Temozolamide and the polymer were solubilized in dichloromethane.
2. The solution obtained in step (1) was emulsified with sodium tauroglycocholate
3. The emulsion obtained in step (2) was subjected to high pressure homogenization.
4. The dichloromethane in the emulsion that is obtained in step (3) was evaporated and the residue was filled in the appropriate container and lyophilized and provided with a sterile saline solution for reconstitution.

C) Bolus Injection of Ligand anchored Temozolomide loaded surface modified PLA nanoparticles
Sr. No Ingredients Quantity
1 PLA 75mg-100mg
2 PLA-PEG-FA conjugated polymer 5-30 mg
3 Temozolamide 20-35 mg
4 Sodium tauroglycocholate 0.3-0.5% solution (15 to 20 ml)

5 PEG 0.5-1%
6 Sodium acetate buffer q. s.

Process:
1. Temozolamide and the polymer were solubilized in dichloromethane.
2. The solution obtained in step (1) was emulsified with sodium tauroglycocholate
3. The emulsion obtained in step (2) was subjected to high pressure homogenization.
4. The dichloromethane in the emulsion that is obtained in step (3) was evaporated and the residue was filled in the appropriate container and lyophilized and provided with a sterile saline solution for reconstitution.

D) Bolus Injection of Ligand anchored Methotrexate loaded surface modified PLA nanoparticles
Sr. No Ingredients Quantity
1 PLA 75mg-100mg
2 PLA-PEG-FA conjugated polymer 5-30 mg
3 Methotrexate 20-25 mg
4 Sodium tauroglycocholate 0.3-0.5% solution (15 to 20 ml)

5 Sodium acetate buffer q. s.
Process:
1. Methotrexate and the polymer were solubilized in dichloromethane.
2. The solution obtained in step (1) was emulsified with sodium tauroglycocholate
3. The emulsion obtained in step (2) was subjected to high pressure homogenization.
4. The dichloromethane in the emulsion that is obtained in step (3) was evaporated and the residue was filled in appropriate container and lyophilized and provided with a sterile saline solution for reconstitution.

It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the spirit of the invention. Thus, it should be understood that although the present invention has been specifically disclosed by the preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and such modifications and variations are considered to be falling within the scope of the invention.

It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

It must be noted that, as used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "an excipient" includes a single excipient as well as two or more different excipients, and the like. ,CLAIMS:WE CLAIM:

1. A pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs or any of their pharmaceutically acceptable salts, solvates, complexes, hydrates, isomers, esters, tautomers, anhydrates, enantiomers, polymorphs, prodrugs or derivatives thereof and one or more pharmaceutically acceptable excipients.

2. A pharmaceutical composition according to claim 1, wherein the polymer is polylactic acid (PLA) and polylacticcoglycolicacid (PLGA).

3. A pharmaceutical composition according to claim 1, wherein the anticancer drug is methotrexate or temozolamide.

4. A pharmaceutical composition according to any preceding claim, wherein the nanoparticles have an average particle size of less than or equal to about 2000 nm.

5. A pharmaceutical composition according to any preceding claims for parenteral administration.

6. A pharmaceutical composition according to claim 5, wherein the dosage form for parenteral administration is in the form of a liquid, gel, bolus, depots, implant, biodegradable or non-biodegradable microparticles or microspheres.

7. A pharmaceutical composition according to any preceding claims wherein the pharmaceutically acceptable excipients are selected from solvents, emulsifiers, surfactants, buffering agents, surface modifiers, ligands and cryoprotectants.

8. A pharmaceutical composition according to any preceding claim, further comprising at least one additional active ingredient selected from alkylating agents, anti-metabolites, anti-microtubule agents, topoisomerase inhibitors or antitumor antibiotics, DNA linking agents, biological agents or bisphosphonates.

9. A process for preparing a pharmaceutical composition comprising polymeric nanoparticles of anticancer drugs, said process comprising the admixing of the nanoparticles of anticancer drugs with polymer and optionally with other pharmaceutically acceptable excipients followed by emulsification, homogenisation, solvent evaporation and lyophilisation and further processing it into the desired dosage form.

10. A pharmaceutical composition according to any one of claims 1 to 8 for use in the treatment of brain tumours.

11. A pharmaceutical composition as described herein with reference to the examples.

Dated this 3rd day of December, 2014

Dr. Gopakumar G. Nair
(Regn.No.: IN/PA 509)
Agent for Applicant
Gopakumar Nair Associates