Aqueous solubility of high concentrated caffeine using hydrotrope and the application to the anti-cellulite cosmetics

This study presents measurements of the aqueous solubility of caffeine at a temperature ranging from 5 to 40°C. And the low water solubility of caffeine was increased by using a hydrotropic solubilization system. Solubility was measured with a single hydrotropic system of niacinamide or betaine and a mixed hydrotropic system of niacinamide and betaine. As a result, it was possible to prepare a high-concentration aqueous caffeine solution of about 4% at 5.9°C and about 25% at 39.9°C. The modified Apelblat equation was applied to predict the temperature dependence of caffeine solubility in aqueous solutions containing niacinamide, and our experimental data showed good agreement with the correlated values. We propose the results of this study as basic data for the development of anti-cellulite cosmetics.