Study On The Sustained-release Oral Drug Delivery Systems Of Curcumin

Curcumin, one of the most widely used natural active constituents with greatvariety of beneficial biological and pharmacological activities, is a typical Class IIdrug with a very short biologic half-life, and was used as the model drug. The aim ofthis paper was to develop sustained-release solid dispersion systems by employingwater-insoluble carrier for release control, solubility/dissolution enhancement andoral bioavailability improvement of curcumin.High-performance liquid chromatography was established in quantitativedetermination of the drug in vitro/vivo. Curcumin was determined to be insoluble inwater with high liposolubility and sensitive with light and pH. The purity of theconventional products of curcumin was improved to be99.04%through columnchromatography.Solid dispersions were prepared with cellulose acetate by the solvent evaporationtechnique. Two formulations were chosen for the following studies: Curcumin:cellulose acetate=1:10(w/w,10%mannitol); Curcumin: cellulose acetate=1:1(w/w,10%PEG6000). Solid state characterization techniques revealed thecrystallinity decrease nature of curcumin in solid dispersions. Solubility/dissolutionand wettability of curcumin were enhanced in the formulations in comparison withpure drug. Sustained-release profiles or controlled-release profoles of curcumin fromthe solid dispersions were ideally achieved in vitro up to12h.Microparticles wre prepared with chitosan and sodium tripolyphosphate byionotropic gelation method. The optimal formulation was as follow:curcumin/chitosan=1:1(w/w,0.3%sodium tripolyphosphate). The microparticlespossessed an average diameter of58.50μm, drug loading of33.50%, encapsulationefficiency of85.20%, and yield of71.33%. Solubility/dissolution and wettability ofcurcumin were enhanced in the formulations in comparison with pure drug.Sustained-release profiles of curcumin from the solid dispersions were ideallycontrolled in vitro up to12h.The sustained-release solid dispersion systems improved the drug stabilityespecially the light stability significantly. The appearance, particle size, flowability,content and dissolution of the formulations changed slightly in6months.The prepared drug delivery system achieved higher drug loading efficiency than the other ones. The formulations provided improved pharmacokinetic parameter inrats as compared with pure drug with good in vivo-in vitro correlations. The resultsobtained from this paper suggests that the developed sustained-release soliddispersion systems successfully enhanced solubility and sustained release of thepoorly water-soluble drug curcumin, and eventually, improved its oral bioavailabilityeffectively.