Enhanced dissolution performance of curcumin with the use of supersaturatable formulations

The goal of this research was to employ formulation strategies to develop supersaturatable formulations for curcumin, a poorly water-soluble drug to improve the in vitro dissolution performance. Self-emulsifying lipid-based formulations and hydrophilic carrier formulations with polymeric precipitation inhibitors were designed to achieve supersaturation upon dilution. In vitro dissolution of curcumin from each formulation was performed, in addition to assessment of the utility of polymers such as polyvinylpyrrolidone (PVP), hydroxypropyl methyl cellulose (HPMC) as precipitation inhibitors. For the hydrophilic solvent formulation, it was observed that the presence of 10% w/w polymer results in curcumin concentrations almost 100-fold greater compared to the formulation without the polymer. Incorporation of polymer in the SEDDS formulation results in a supersaturated solution of curcumin with concentrations identical to the theoretical starting dose. The high drug concentrations were sustained for 3 h as compared to the self-emulsifying formulation without the polymer. The low dissolution of curcumin in the neat hydrophilic solvent and self-emulsifying formulation is attributed to the uncontrolled precipitation of the drug upon mixing with the dissolution media, which is a result of formation of an unstable supersaturated solution. Upon relative assessment, the rank order in which the polymers inhibited precipitation was PVP-K30 < PVP-K90 < HPMC.