Abstract
The aim of the current research was to develop and characterize curcumin-gamma cyclodextrin inclusion complexes in order to enhance solubility and rate of dissolution of poorly soluble curcumin. Based on the stoichiometric ratio of 1:1, the inclusion complexes of curcumin with gamma-cyclodextrin were prepared by freeze drying method. The prepared dried and solidified inclusion complexes were characterized with the help of infrared spectroscopy, differential scanning calorimetry, and X-ray diffractometry. The comparative evaluation of solubility and rate of dissolution were investigated and compared with pure curcumin. Dissolution study demonstrated only 10% release from pure curcumin at 1 hour as opposed of approximately 72% release form freeze dried curcumin complexes. The freeze dried complexes exhibited almost complete release after 5 hours while only 34% release was observed from the pure curcumin during the same time period. Therefore, the freeze dried complex provided approximately 3 to 7-fold enhancement in the dissolution and release of curcumin over a period of 6 hours of dissolution testing. The kinetics of the in vitro release behaviors of the curcumin and curcumin complexes were investigated by applying various models such as zero order, first order, Higuchi and Peppas models. The release of the curcumin was observed to follow the first order release kinetics, since the correlation coefficient (R2) for the first order was the highest in comparison to other kinetic models.