The solubilization of poorly water-soluble progesterone derivatives into micelles of a gemini surfactant was investigated in an aqueous medium. The aqueous solubility at different temperatures was determined spectroscopically using an ultraviolet visible light spectrophotometer. Thermodynamic parameters for the solubilization were calculated under the basis of the solubility change against temperature. The solubility of progesterone was quite low and remained constant below the critical micelle concentration (cmc) of the surfactant. On the other hand, the solubility increased considerably with increasing surfactant concentration above the cmc. It was suggested that the solubilizates were located in the vicinity of polar regions of micelles.
Keywords: gemini surfactant; micelle; progesterone; solubilization.