DESC:Field of the Invention:
The present invention relates to compositions comprising one or more curcuminoids, and at least one dissolution enhancer, exhibiting improved dissolution, and a process for the preparation thereof.

Background of the Invention:
Curcuminoids are practically insoluble in water at acidic and neutral pH, and rapidly decompose at alkaline pH. Various attempts have been made in prior art to improve the solubility of curcuminoids.

US Patent 9,504,754 and US Patent Publication No. US 2018/0064821 provide curcuminoid formulations comprising: nanoparticles or microparticles loaded with curcuminoid-polymer complex, comprising at least one curcuminoid component; at least one polymer or co-polymer component having a backbone comprising polymethacrylate or methyl methacrylate; and a surfactant component, wherein the curcuminoid-polymer complex is formed by a process comprising: dissolving the curcuminoid component and the polymer or co-polymer component, in an organic solvent, to form a curcuminoid-polymer solution; adding the curcuminoid-polymer solution to an aqueous solution having the surfactant to precipitate the curcuminoid-polymer complex and form a dispersion of the complex; and removing the organic solvent from the dispersion to collect the curcuminoid-polymer complex.

PCT Patent Publication No. WO/2006/022012 provides novel and stable solid dispersions of curcumin, by dissolving curcumin together with polyvinylpyrrolidone in an alcoholic solvent and then spray-drying.

US Patent Publication No. US 2013/0303628 A1 provides a melt-processed solid dispersion product comprising one or more curcuminoids, a nutritionally acceptable thermoplastic polymer, and a phosphatide (like glycerophospholipids, phosphoglycerides, phosphatidylcholines, lecithin).

US Patent Publication No. US 2010/0316631 A1 illustrates the design and synthesis of a novel class of water soluble curcumin-based compounds wherein the curcumin-based compound is chemically conjugated to at least one solubilizing agent selected from the group consisting of: poly(ethylene glycol) (PEG), derivatives of PEG, poly(substituted-2-oxazoline) (POZ), derivatives of POZ, an amino acid, a polypeptide and an antibody.

US Patent 8,568,815 B2 relates to methods of solubilizing curcumin by forming cyclodextrin complexes. The patent discloses methods of manufacturing curcumin complexes using steps of contacting curcumin with cyclodextrin, in an aqueous phase at a pH of at least 11 to form a solution of curcumin and cyclodextrin, lowering the pH of said solution to below pH 8, and recovering the solution thus obtained containing the cyclodextrin complex of curcumin, said complex being dissolved in the aqueous phase.

Avinash et. al. disclose solid dispersions of curcumin using Eudragit EPO, prepared using the spray drying and the rota-evaporation technique, using organic solvents or aqueous solvents, and surfactants like Cremophore™ RH 40 and Tween™ 80 (Avinash B. Gangurde, Harish S. Kundaikar, Sharadchandra D. Javeer, Divakar R. Jaiswar, Mariam S. Degani, Purnima D. Amin, Journal of Drug Delivery Science and Technology 2015 29:226-237).

Jinglei et. al. disclose solid dispersions of curcumin with Eudragit EPO using the solution mixing technique wherein Eudragit® EPO is dissolved in pH 4.5 sodium acetate buffer solution, and curcumin acetone solution is dropped into the Eudragit® EPO solution under magnetic stirring. Acetone is removed by rotary evaporation and curcumin-Eudragit® EPO powder is retrieved after lyophilization. (Jinglei Li, Woo Lee, Gye Hwa Shin, Xiguang Chen, Hyun Jin Park, European Journal of Pharmaceutics and Biopharmaceutics 2015 94: 322–332).

Different formulation approaches have been taken to circumvent the poor aqueous solubility and/or oral bioavailability of curcuminoids like solubilization, solid dispersions, conjugation, micelle formation, microencapsulation, nanoparticle formation, self-emulsifying delivery system (SMEDDS) formation, microemulsification, nanoemulsification and cyclodextrin complexation.

The techniques used in prior art use multi-step processes which are complex and long, use high molecular weight cyclodextrins, surfactants, lipids, fats, oils and/or organic/aqueous solvents. This reduces their practical and commercial utility.

The present invention provides curcuminoids compositions comprising at least one curcuminoid and at least one dissolution enhancer, the said compositions exhibiting improved dissolution.

The present invention provides a method of said compositions being with minimal excipients, and using a simple, yet effective process.

OBJECTS OF THE INVENTION
The object of the present invention is to provide compositions comprising one or more curcuminoids, and at least one dissolution enhancer.

Another object of the present invention is to provide compositions comprising one or more curcuminoids, and at least one dissolution enhancer, wherein the one or more curcuminoids exhibit improved dissolution.

Another object of the present invention is to provide orally bioavailable compositions comprising one or more curcuminoids, and at least one dissolution enhancer.

Another object of the present invention is to provide stable compositions comprising one or more curcuminoids, and at least one dissolution enhancer.

Yet another object of the invention is to provide compositions, comprising one or more curcuminoids, and at least one dissolution enhancer, the compositions being substantially free of surfactants.

Yet another object of the invention is to provide compositions, comprising one or more curcuminoids, and at least one dissolution enhancer, the compositions being free of oils, fats, lipids and/or the like.

Another object of the invention is to provide compositions, comprising one or more curcuminoids, and at least one dissolution enhancer, prepared by a process which does not use solvents.

Yet another object of the invention is to provide a melt technique for preparation of said compositions, comprising one or more curcuminoids.

Yet another object of the invention is to provide compositions comprising one or more curcuminoids and at least one dissolution enhancer, with a dissolution of at least 50% in 60 minutes when analyzed in 900 ml of purified water containing 1% sodium lauryl sulphate at 370C, using USP apparatus II (paddle), at 100 revolutions per minute.

Yet another object of the invention is to provide a process for preparation of said compositions comprising one or more curcuminoids, and at least one dissolution enhancer.

Another object of the invention is to provide a process for preparation of said compositions which does not use solvents.

Yet another object of the invention is to provide a process for preparation of said compositions which does not use surfactants.

Yet another object of the invention is to provide a process for preparation of said compositions which does not use oils, fats, lipids and/or the like.

DETAILED DESCRIPTION OF THE INVENTION
Curcuminoids are diaryl heptanoid derivatives isolated from Turmeric, a member of the ginger family (Zingiberaceae). The three major curcuminoids present in Turmeric are: curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin. Curcumin is the principal curcuminoid of Turmeric. Curcuminoids are polyphenols and are responsible for the yellow color of turmeric.

Curcuminoids have been suggested for a variety of therapeutic and prophylactic applications. For example, curcuminoids have a variety of biological activities and pharmacological actions, such as anti-cancer, anti-viral, anti-arthritic, anti-amyloid, antioxidant, anti-inflammatory, anti-obesity, anti-depressant, improves symptoms of neurodegenerative diseases like Parkinson’s, Alzheimer’s, and Huntington’s, improves brain function/health, improving mental health, lowers the risk of brain and heart diseases, regulates cholesterol, lowers the risk of atherosclerosis, improves cardiovascular function, prevents blood clots, improves symptoms of inflammatory bowel disease, improves symptoms of gastrointestinal conditions like constipation/dyspepsia/gastric ulcers/ulcerative colitis/pancreatitis, prevents cystic fibrosis, reduces pain and soreness in post-surgical recovery, relieves symptoms of menstruation, lowers the risk of diabetes, promotes liver health, delays aging, promotes skin and ocular health, and benefits sports nutrition by lowering oxidative stress in muscles, enhancing recovery of and improving muscle performance, improving endurance capacity, improving resistance to fatigue, and improving joint mobility and function.

In spite of these wide span of activities, a major impediment in the development of curcumin formulations is its low bioavailability when administered orally. The therapeutic efficiency of curcuminoids has been highly limited due to poor solubility in water (the maximum solubility was reported to be 11 ng/ml in plain aqueous buffer pH 5.0). Low bioavailability of curcuminoids after oral delivery is attributed to poor aqueous solubility, poor absorption, high pre-systemic metabolism in gastrointestinal tract (GIT), low stability due to degradation in GIT at neutral and alkaline pH, and rapid systemic metabolism to sulfate and glucuronide conjugates leading to short half-life. It has been reported that serum levels in humans after an oral dose of 2g curcumin alone were either undetectable or very low.

The term ‘curcuminoids’ is used herein to mean curcumin (diferuloylmethane), desmethoxycurcumin, or bisdesmethoxycurcumin, including their polymorphs, hydrates, solvates, derivatives and mixtures thereof. Curcuminoids may be isolated from natural sources like the roots or rhizomes, of plants such as curcuma longa, curcuma amada, curcuma angustifolra, curcuma caesia, curcuma zedoaria, curcuma caulina, curcuma aromatics, curcuma wenyjuin, curcuma xanfhorrhiza roxb, or may be synthetic curcuminoids, or may be curcuminoid derivatives.

The one or more curcuminoids in the composition may be in their crystalline form or in the amorphous form or as mixtures of crystalline and amorphous forms.

The curcuminoid(s) may be present in concentrations from 5% to 85% by weight of the composition, preferably in concentrations from 10% to 60% by weight of the composition, more preferably in concentrations from 15% to 50% by weight of the composition, and most preferably in concentrations from 20% to 45% by weight of the composition.

In one of the embodiments the curcuminoid(s) is present in concentrations from 15% to 65% by weight of the composition.

The present invention provides compositions comprising one or more curcuminoids and at least one dissolution enhancer.

One embodiment provides compositions comprising one or more curcuminoids and at least one dissolution enhancer, exhibiting improved dissolution.

Another embodiment, provides compositions comprising one or more curcuminoids and at least one dissolution enhancer, the said compositions being orally bioavailable.

Another embodiment, provides compositions comprising one or more curcuminoids and at least one dissolution enhancer, the said compositions being stable.

Another embodiment of this invention provides the said compositions comprising one or more curcuminoids in an amorphous form.

Yet another embodiment of this invention provides the said compositions in the form of a solid dispersion.

Dissolution enhancers are selected from polymethacrylates like poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) 1:2:1; poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride) 1:2:0.2; poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride) 1:2:0.1, or mixtures thereof.

In a preferred embodiment of the invention, the polymethacrylate is poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) 1:2:1 (commercially available as Eudraguard® Protect).

In one of the embodiments of the invention, the dissolution enhancer is pre-treated with an acid.

The dissolution enhancer(s) may be present in concentrations from 15% to 95% by weight of the composition, preferably in concentrations from 40% to 90% by weight of the composition, more preferably in concentrations from 50% to 85% by weight of the composition, and most preferably in concentrations from 55% to 80% by weight of the composition.

The ratio of the curcuminoid(s) and the dissolution enhancer(s) may range from 1:0.25 to 1:10. Preferably the ratio of the curcuminoid(s) and the dissolution enhancer(s) may range from 1:0.5 to 1:5. More preferably the ratio of the curcuminoid(s) and the dissolution enhancer(s) may range from 1:0.5 to 1:1.

In one of the embodiments of the invention, the composition comprises at least one curcuminoid, at least one dissolution enhancer and at least one monosaccharide sugar alcohol.

Monosaccharide sugar alcohols are selected from mannitol, sorbitol, xylitol or ribitol.

Preferred monosaccharide sugar alcohol is mannitol.

Monosaccharide sugar alcohol(s) may be present from 5% to 75% by weight of the composition.

The ratio of the curcuminoid(s) and the monosaccharide sugar alcohol(s), may range from 10:1 to 1:10, more preferably the ratio may range from 6:1 to 1:6.

In one of the embodiments, the ratio of the curcuminoid(s), the dissolution enhancer(s) and the monosaccharide sugar alcohol(s) ranges from 1: 0.5: 0.25 to 1: 5: 6.

In one of the embodiments of the invention, the composition comprises at least one curcuminoid, at least one dissolution enhancer and at least one organic acid.

Organic acids are selected from citric acid, fumaric acid, ascorbic acid, lactic acid, malonic acid, succinic acid, gluconic acid, maleic acid, malic acid, tartaric acid, benzoic acid, and derivatives thereof.

Preferred organic acids are citric acid, tartaric acid, maleic acid, and/or ascorbic acid.

Organic acid(s) may be present from 1% to 50% by weight of the composition. Preferably they may be present from 5% to 40% by weight of the composition.

The ratio of the curcuminoid(s) and the organic acid(s) may range from 5: 1 to 1: 5, more preferably from 3: 1 to 1: 3, and most preferably from 2: 1 to 1: 2.

In one of the embodiments, the ratio of the curcuminoid(s), the dissolution enhancer(s) and the organic acid(s) ranges from 1: 0.5: 0.5 to 1: 5: 1.5.

In one of the embodiments, the ratio of the curcuminoid(s), the dissolution enhancer(s), the monosaccharide sugar alcohol(s) and the organic acid(s) ranges from 1: 0.5: 0.25: 0.5 to 1: 5: 6: 1.5.

In one embodiment, the compositions comprise one or more curcuminoids, and at least one dissolution enhancer, the said compositions being substantially free of surfactants.

The present invention provides compositions comprising one or more curcuminoids, and at least one dissolution enhancer, the said compositions being free of oils, fats, lipids and/or the like.

The compositions of the present invention may optionally comprise at least one excipient selected from the group of diluents, binders, disintegrants, lubricants, and glidants.

The diluents are selected from diluents known in the art, such as microcrystalline cellulose, silicified microcrystalline, cellulose, powdered cellulose, microfine cellulose, corn starch, calcium phosphate, dibasic calcium phosphate, tribasic calcium phosphate, calcium sulfate, or mixtures thereof. The diluents may also be selected from glucose, lactose, sucrose, dextrose, fructose, compressible sugar, or mixtures thereof.

The diluents may be present in concentrations from 0.1% to 70% by weight of the composition. Preferably, the diluents may be present in concentrations from 5% to 50% by weight of the composition.

The binders are selected from the group of cellulose derivatives such as hydroxypropylmethyl cellulose (HPMC), hydroxypropyl cellulose (HPC), ethylcellulose, carboxymethylcellulose (CMC), sodium CMC, potassium CMC, calcium CMC, methylcellulose, hydroxyethyl cellulose (HEC), microcrystalline cellulose; polyvinylpyrrolidone (PVP), vinyl pyrrolidone-vinyl acetate copolymer, polyvinyl alcohol, starch, carbomer, gums like xanthan gum, guar gum, acacia, locust bean gum, alginates, or mixtures thereof.

The binders may be present in concentrations from 1% to 50% by weight of the composition. Preferably, the binders may be present in concentrations from 5% to 25% by weight of the composition.

The disintegrants are selected from sodium starch glycolate, crospovidone, croscarmellose sodium, croscarmellose calcium, croscarmellose potassium, sodium carbonate, sodium hydrogen carbonate, calcium carbonate, starch, starch 1500, modified starch, pregelatinized starch, crosslinked carboxymethyl starch, sodium hydrogen carbonate, hydroxypropyl cellulose, sodium carboxymethylcellulose or mixtures thereof.

The disintegrants may be present in concentrations from 1% to 25% by weight of the composition. Preferably, the disintegrants may be present in concentrations from 5% to 20% by weight of the composition.

The lubricants are selected from magnesium stearate, calcium stearate, sodium benzoate, talc, or mixtures thereof. The lubricants may be present in concentrations from 0.25% to 5% by weight of the composition.

The glidants are selected from suitable glidants known in the art. An example of a suitable, acceptable glidant is colloidal silicon dioxide. The glidants may be present in concentrations from 0.1% to 10% by weight of the composition.

The acids may be selected from commonly used acids including hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, acetic acid, citric acid, formic acid, gluconic acid, lactic acid, oxalic acid, tartaric acid, ascorbic acid, maleic acid, malic acid, malonic acid, succinic acid, fumaric acid, benzoic acid, or their derivatives.

The compositions of the invention, preferably in the form of tablets, capsules, powders, granules, beads, pellets, lozenges, and pastilles, may optionally be coated with a film coating layer comprising film coating materials, and optionally comprising plasticizers, colorants, pigments, lubricants, and diluents.

The invention also provides a process for preparation of said compositions.

In one embodiment, the compositions comprise one or more curcuminoids, and at least one dissolution enhancer, the said compositions being prepared by a process that does not use surfactants.

The compositions of the present invention comprise one or more curcuminoids, and at least one dissolution enhancer, the said compositions being prepared by a process that does not use oil, fats, lipids and/or the like.

The one or more processes that can be used to manufacture the compositions of the present invention include sifting, mixing, heating, melting, cooling, extruding, and milling. Processes like granulation, compression, compaction, spraying, coating, layering, and filling into capsules may further be used to manufacture the compositions.

In one of the embodiments, a composition comprising one or more curcuminoids, and at least one dissolution enhancer, is prepared as follows: curcuminoid(s) is mixed with dissolution enhancer(s), and optionally with one or more monosaccharide sugar alcohols, and/or one or more organic acids, and optionally with one or more diluents, binders, disintegrants, lubricants, and/or glidants, to obtain a mixture. The mixture is heated in a hot melt extruder to obtain a molten mass. The molten mass is extruded to obtain extrudates. The extrudates are cooled and milled to obtain the curcuminoid composition. The cooled and milled extrudates may further be mixed with at least one monosaccharide sugar alcohol, and/or at least one organic acid to give curcuminoid compositions. The cooled and milled extrudates may further be mixed with diluents, binders, disintegrants, lubricants, and/or glidants to give curcuminoid compositions. The curcuminoid compositions may further be processed by granulation, compression, compaction, spraying, coating, layering, or filling to provide tablet or capsule dosage forms.

One embodiment of this invention provides curcuminoid compositions that are prepared by a process that does not use solvents.

Another embodiment of this invention provides a process for preparation of curcuminoid compositions that does not use solvents.

Yet another embodiment of this invention provides a process for preparation of said compositions, comprising one or more curcuminoids that does not use organic solvents.

Yet another embodiment of this invention provides a process for preparation of said compositions, comprising one or more curcuminoids that does not use aqueous solvents.

The ratio of the curcuminoid(s) and the monosaccharide sugar alcohol(s), in the extrudates, may range from 1: 0.1 to 1: 5, more preferably from 1: 0.1 to 1: 2.5, and most preferably from 1: 0.2 to 1: 1.

The compositions of the present invention can be used in oral, topical or parenteral administration.

For oral administration, the compositions can be used in the form of tablets, capsules, powders, granules, beads, pellets, lozenges, pastilles, syrups, elixirs, solutions, suspensions, dispersions, emulsions and the like.

The compositions were analyzed for their dissolution in accordance with the recommendation of Dietary Supplements Compendium (DSC) 2015, United States pharmacopeia (USP) using the following conditions: 900 ml of purified water containing 1% sodium lauryl sulphate, USP apparatus II (paddle) at 100 revolutions per minute, 370C.

The compositions of the present invention were formulated to exhibit a cumulative dissolution of:
• not less than 50% by weight of curcuminoids in 120 minutes,
• preferably not less than 50% by weight of curcuminoids in 60 minutes,
• more preferably not less than 50% by weight of curcuminoids in 45 minutes,
• more preferably not less than 50% by weight of curcuminoids in 30 minutes and
• most preferably not less than 50% by weight of curcuminoids in 15 minutes.

Preferred compositions of the present invention were formulated to exhibit a cumulative dissolution of:
• not less than 70% by weight of curcuminoids in 120 minutes,
• preferably not less than 70% by weight of curcuminoids in 60 minutes,
• more preferably not less than 70% by weight of curcuminoids in 45 minutes, and
• most preferably not less than 70% by weight of curcuminoids in 30 minutes.

Preferred compositions of the present invention were formulated to exhibit a cumulative dissolution of:
• not less than 80% by weight of curcuminoids in 120 minutes,
• preferably not less than 80% by weight of curcuminoids in 60 minutes, and
• more preferably not less than 80% by weight of curcuminoids in 45 minutes.

Most preferred compositions of the present invention were formulated to exhibit a cumulative dissolution of:
• not less than 90% of curcuminoids in 120 minutes, and
• more preferably not less than 90% by weight of curcuminoids in 60 minutes.

The invention is now illustrated with non – limiting examples.

Example 1
Curcuminoid powder (containing not less than 95% curcuminoids) (21.04%), poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) (21.04%), citric acid monohydrate (28.84%) and mannitol (SD 200) (10.64%) were sifted through 30 mesh ASTM and mixed for 10 minutes to give a mixture. The mixture was hot melt extruded under the conditions mentioned in Table 1.

Table 1: Hot melt extruder conditions for processing of example 1
Temperature of Chambers
Chamber Temperature (oC)
2 25
3 40
4 90
5 160
6 180
7 180
8 180
Die Zone 150
Extruder RPM = 70
Feeder RPM = 40

The extrudates were cooled and milled in a co-mill (1 mm sieve) to give the extrudate powder. The extrudate powder was sifted through 30 mesh ASTM. Mannitol 200 SD (10.64%) and anhydrous colloidal silica (7.8%) were sifted through 30 mesh ASTM. The extrudate powder was blended with the sifted mannitol and anhydrous colloidal silica in a blender for 10 minutes to give the powder composition. The powder composition equivalent to 50mg of curcuminoids was filled in HPMC capsules of size 00.

Physical Mixture
A Physical mixture of the ingredients used in example 1 was prepared by sifting the individual ingredients through 30 mesh ASTM and blending them for 10 minutes.

Example 2
Curcuminoid powder (containing not less than 95% curcuminoids) (50%), and poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) (50%), were sifted through 30 mesh ASTM and blended for 10 minutes to give a mixture. The mixture was hot melt extruded using conditions similar to example 1. The extrudates were cooled and milled in a co-mill (1 mm sieve) to give the extrudate powder. The extrudate powder was sifted through 30 mesh ASTM to give the powder composition.

Example 3
Curcuminoid powder (containing not less than 95% curcuminoids) (10.52%), poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) (10.52%), citric acid (12.02%) and Mannitol 200 SD (5.32%) were sifted through 30 mesh ASTM and mixed for 10 minutes to give a mixture. The mixture was hot melt extruded using the conditions mentioned in table 2. The extrudates were cooled and milled in a co-mill (1 mm sieve) to give the extrudate powder. The extrudate powder was sifted through 30 mesh ASTM. Mannitol 25C (53.82%) and anhydrous colloidal silica (7.80%) were sifted through 30 mesh ASTM. The extrudate powder was mixed with the sifted mannitol and anhydrous colloidal silica in a blender for 10 minutes to give the powder composition. The powder composition equivalent to 50mg of curcuminoids was filled in HPMC capsules of size 00.

Table 2: Hot melt extruder conditions used in example 3
Temperature of Chambers
Chamber Temperature (oC)
2 25
3 40
4 90
5 160
6 200
7 200
8 200
Die Zone 200
Extruder RPM = 35
Feeder RPM = 35

Example 4
Curcuminoid powder (containing not less than 95% curcuminoids) (42.08%), poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) (21.04%), citric acid (21.04%) and mannitol 200 SD (14.00%) were sifted through 30 mesh ASTM and mixed for 10 minutes to give a mixture. The mixture was hot melt extruded using the same conditions as example 3. The extrudates were cooled and milled in a co-mill (1 mm sieve) to give the extrudate powder. The extrudate powder was sifted through 30 mesh ASTM. Anhydrous colloidal silica (1.84%) was sifted through 30 mesh ASTM. The extrudate powder was mixed with the sifted anhydrous colloidal silica in a blender for 10 minutes to give the powder composition. The powder composition equivalent to 50mg of curcuminoids was filled in HPMC capsules of size 00.

Example 5
Poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) (61.72%), and citric acid (12.34%) were sifted through 30 mesh ASTM and mixed for 10 minutes to give acid-pretreated poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate). Curcuminoid powder (containing not less than 95% curcuminoids) (12.34%) and mannitol 200 SD (12.34%) were sifted through 30 mesh ASTM, and mixed with the acid pre-treated poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) for 10 minutes to give a mixture. The mixture was hot melt extruded similar to example 3. The extrudates were cooled and milled in a co-mill (1 mm sieve) to give the extrudate powder. The extrudate powder was sifted through 30 mesh ASTM. Anhydrous colloidal silica (1.23%) was sifted through 30 mesh ASTM. The extrudate powder was mixed with the sifted anhydrous colloidal silica in a blender for 10 minutes to give the powder composition. The powder composition equivalent to 50mg of curcuminoids was filled in HPMC capsules of size 00.

Dissolution Studies:
Curcuminoid powder (95%), the physical mixture of example 1, the powder composition of examples 1 to 5, all equivalent to 50 mg of curcuminoids, were analyzed for dissolution of curcuminoids at conditions mentioned earlier. The results of the same are given in Table 4.

Table 4: Dissolution of curcuminoid powder 95%, physical mixture and examples 1 to 5

Time
(min) % Cumulative Dissolution Profile
Curcuminoid Powder (95%) Physical Mixture Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5
15 18 18 55 50 96 37 68
30 27 24 73 67 104 53 86
45 33 31 83 78 106 67 95
60 38 37 88 84 104 76 98
120 53 51 96 91 105 93 101
* Ex. = Example; min = minutes

Table 4 clearly indicates that compositions of the present invention comprising curcuminoid powder 95% and at least one dissolution enhancer (examples 1 to 5), prepared through the hot melt technology, exhibit a significantly higher rate and extent of dissolution, when compared to either curcuminoid powder 95% alone or the physical mixture.

Stability Studies:
The compositions of example 1 were subjected to stability studies. The capsules of example 1 were packed in HDPE bottles with 1g silica, and Alu-Alu blister. Both packs were subjected to storage conditions of 40°C and 75% relative humidity (RH), and 25°C and 60% relative humidity (RH), for a period of six months. The compositions were studied for their dissolution at 3 and 6 months, using the conditions mentioned in DSC 2015 (USP). Table 6 and 7 shows the dissolution of the compositions at 60 minutes after storage for at 3 and 6 months.

A stable curcuminoid composition does not differ in its dissolution from the initial by more than 15%, preferably not more than 10% and more preferably not more than 5%, when stored at 40°C/75% RH for at least 6 months.

Table 6: Dissolution at 3 and 6 months after storage at 40°C/75% RH
Pack % Cumulative Dissolution at 60 minutes after storage at 40°C/75% RH
0 month 3 month 6 month
HDPE bottle 88 87 89
Alu-Alu blister 88 94 95

Table 7: Dissolution at 3 and 6 months after storage at 25°C/60% RH
Pack % Cumulative Dissolution at 60 minutes after storage at 25°C/60% RH
0 month 3 month 6 month
HDPE bottle 88 87 87
Alu-Alu blister 88 95 91

The stability data in table 6 and 7 clearly illustrates that present invention provide stable curcuminoid compositions, the said compositions comprising one or more curcuminoids and at least one dissolution enhancer.

The initial dissolution (0 month) of the composition at 60 minutes and its dissolution at 60 minutes after storage at 40°C/75% RH and 25°C/60% RH storage conditions, do not differ by more than 15%, at both 3 months and 6 months.

Dissolution of the composition of example 1, after storage at 40°C/75%RH and 25°C/60%RH, was found to be not less than 85% in 60 minutes, at both 3 months and 6 months.

In-vivo Studies
An open label, randomized, single oral dose, in-vivo study of example 1 of the present invention was conducted in normal, healthy, adult, human subjects under fasting conditions. The subjects were dosed with 6 x 250 mg capsules. Blood samples were collected from the subjects pre-dosing and at regular intervals of time post-dosing. The blood plasma were analyzed for free curcumin, total curcumin, total demethoxycurcumin, total bisdemethoxycurcumin and total tetrahydrocurcumin.

Table 8 gives the results of the In-vivo study.

Table 8: In-vivo study data
Parameter Mean (± SD)
Cmax of Total Curcumin 432.5027 ± 178.36781 ng/ml
AUC0-24 of Total Curcumin 2556.1262 ± 907.02740 ng/ml
Tmax of Total Curcumin 1.556 ± 0.5270 hrs
Cmax of Total Demethoxycurcumin 68.5882 ± 31.10032 ng/ml
AUC0-24 of Total Demethoxycurcumin 298.5203 ± 101.84732 ng/ml
Tmax of Total Demethoxycurcumin 1.556 ± 0.5270 hrs
Cmax of Total Bisdemethoxycurcumin 5.6230 ± 2.62304 ng/ml
AUC0-24 of Total Bisdemethoxycurcumin 31.8592 ± 13.95390 ng/ml
Tmax of Total Bisdemethoxycurcumin 2.000 ± 0.5000 hrs
Cmax of Total Tetrahydrocurcumin 201.0511 ± 50.06872 ng/ml
AUC0-24 of Total Tetrahydrocurcumin 1768.3813 ± 467.20461 ng/ml
Tmax of Total Tetrahydrocurcumin 2.222 ± 0.8333 hrs
Cmax of Free Curcumin 1592.5751 ± 796.54894 pg/ml
AUC0-24 of Free Curcumin 3501.6716 ± 1459.22838 pg/ml
Tmax of Free Curcumin 1.111 ± 0.3333 hrs
ng = nanogram; pg = picogram; ml = milliliter; hrs = hours

The in-vivo data in table 8 shows that the compositions of the present invention, after oral administration, exhibit the desired oral bioavailability, measured as the area-under-the-curve (AUC0-24) of free curcumin, total curcumin, total demethoxycurcumin, total bisdemethoxycurcumin and total tetrahydrocurcumin in blood plasma.

The time to reach maximum plasma concentrations (Tmax) values and the maximum plasma concentrations (Cmax) values, clearly indicate that the said compositions exhibit a high rate of absorption into the blood.

After oral administration, the curcuminoids from the compositions of the present invention exhibit rapid absorption, measured as the time to reach maximum plasma concentrations (Tmax) values. Thus the curcuminoids are made available in the blood, quickly and in sufficient amounts, to enable them to show their expected biological activities and pharmacological action.

Thus, the present invention provides curcuminoid compositions with improved dissolution, said compositions being stable and orally bioavailable. ,CLAIMS:We Claim

1. A composition comprising a melt extrudate of one or more curcuminoids, and at least one dissolution enhancer, the said composition being substantially free of surfactants.

2. A composition as claimed in claim 1 wherein the dissolution enhancer is selected from poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) 1:2:1; poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride) 1:2:0.2; poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride) 1:2:0.1; or mixtures thereof.

3. The composition as claimed in claim 1 wherein the dissolution enhancer is poly(butyl methacrylate, (2-dimethylaminoethyl) methacrylate, methyl methacrylate) 1:2:1.

4. A composition as claimed in claims 1 to 3 wherein the at least one dissolution enhancer comprises 15% to 95% by weight of the composition.

5. A composition as claimed in claims 1 to 3 wherein the ratio of the curcuminoid(s) and the dissolution enhancer(s) ranges from 1:0.25 to 1:10.

6. The composition as claimed in claim 1 wherein the composition further comprises an excipient selected from a monosaccharide sugar alcohol, an organic acid or mixtures thereof.

7. The composition as claimed in claim 6 wherein the ratio of the one or more curcuminoid(s) and the monosaccharide sugar alcohol(s) ranges from 10:1 to 1:10.

8. The composition as claimed in claim 6 wherein the ratio of the one or more curcuminoid(s) and the organic acid(s) ranges from 5:1 to 1:5.

9. The composition as claimed in claim 1 wherein the composition is prepared without the use of solvents.

10. A process for preparing a composition comprising one or more curcuminoids, and at least one dissolution enhancer, comprising steps of
• mixing one or more curcuminoids, with at least one dissolution enhancer, and optionally with at least one monosaccharide sugar alcohol and/or at least one organic acid
• heating the mixture in a hot melt extruder to obtain a molten mass
• extruding the molten mass to obtain extrudates
• cooling and milling the extrudates
wherein the said process does not use any solvents.