Formulation and Characterization of Solid Dispersion Containing Capsaicin for the Treatment of Diabetes

Background: Chili peppers are widely used in many cuisines as a spice, and capsaicin is the main component. It has been reported that capsaicin acts as an antihyperglycemic agent. However, it shows poor aqueous solubility and bioavailability. Objective: The is to enhance the aqueous solubility and antihyperglycemic activity of capsaicin through solid dispersion formulation. Methods: Solid dispersions were prepared by the solvent evaporation method using polyethylene glycol 6000 (PEG 6000) as a hydrophilic carrier. Polymer-drug miscibility and drug crystallinity were characterized through the differential thermal analysis and X-ray powder patterns analysis. Solid dispersions were evaluated for solubility, in vitro drug dissolution and in vivo animal study in rats. Results: Results of x-ray powder patterns analysis showed a considerable reduction of drug crystallinity in solid dispersion. Differential thermal analysis result revealed a complete disappearance of capsaicin melting onset temperature in solid dispersion. From the phase solubility data, it was observed that the aqueous solubility of capsaicin was increased with increasing concentration of PEG 6000. Solid dispersion formulation showed considerable enhancement of in vitro release of drugs in comparison to pure capsaicin. In vivo animal study in rats shows that the solid dispersion containing capsaicin significantly reduced the blood glucose level in comparison to the free capsaicin. Conclusion: Higher anti-hyperglycemic effect of capsaicin loaded solid dispersion in comparison to the pure drug may be due to the enhancement of aqueous solubility of capsaicin. Thus, the solid dispersion of capsaicin showed a simple approach for capsaicin delivery with improved antidiabetic activity.