Pharmaceutical Modifications of Capsaicin to Enhance its Bioavailability

Capsaicin or N-vanillyl-8-methyl-6-(E)-none amide, a unique key constituent from the Capsicum genus, is a pharmaceutical agent with a wide range of therapeutic applications like diabetes, obesity, cancer, and other inflammatory conditions. Clinically approved capsaicin pharmaceutical formulations are known to associate with certain concentration-dependent side effects, including skin irritation and burning sensations. Further, the major caveats of capsaicin are its short half-life, and it belongs to Biopharmaceutical Classification System (BCS) II on account of its low bioavailability. About 60% of drug candidates fail to reach the market and do not attain their full potential because of low solubility and poor bioavailability behaviour, and thus present the most challenging aspects for new chemical entities in the drug development process. Nano-sizing, micronization, solid dispersions, cyclodextrins, crystal engineering, solid lipid nanoparticles, and additional colloidal drug delivery systems like microemulsions, self-emulsifying and self-microemulsifying systems, and liposomes are some of the newly developed methods to promote the saturation solubility, dissolution rate, and subsequently the bioavailability of BCS Class II. The present chapter aims to summarize the so far adopted technologies to upsurge the BCS parameters of capsaicin and alleviate its associated side effects. The development of new capsaicin formulations with enhanced bioavailability and delivery systems will raise hopes for innovative applications of capsaicin for health complications.