Development and Characterization of Solid Dispersion System for Enhancing the Solubility and Dissolution Rate of Dietary Capsaicin

Background: Capsaicin is a pungent component of chili peppers that suppresses the growth of various cancer cell lines including breast cancer. However, it shows extremely low oral bioavailability due to its poor water solubility. Objective: The objective of the present work was to improve the solubility and dissolution rate of capsaicin. Methods: Solid dispersions were prepared by the solvent evaporation method using different molar ratios of capsaicin and urea (1:1, 1:2, and 1:3). Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) study were used to characterize the solid dispersion. Solid dispersions were evaluated for solubility, dissolution rate and in vitro cytotoxicity in breast cancer cell lines. Results: XRD and DSC studies exhibited the reduced crystallinity of a drug in solid dispersion. Phase solubility study shows that the drug solubility increased by increasing carrier concentration. In vitro release study of the solid dispersion showed the faster dissolution of a drug with increasing carrier concentration. Solid dispersion formulation effectively inhibited the growth of MCF-7 human breast cancer and MDA-MB-231 triple negative human breast cancer cells in an MTT assay that measures metabolic activity, but only slightly decreased cell viability when compared to capsaicin alone. Conclusion: The present study demonstrated that solid dispersion of capsaicin in PEG 6000 overcomes the problems related to the poor aqueous solubility of this drug and improving its dissolution rate.