Abstract

SOLUBILITY ENHANCEMENT OF AZILSARTAN MEDOXOMIL USING MIXED HYDROTROPY

Kunal Sharad Surwade and Ravindra Bhanudas Saudagar*

ABSTRACT

Low aqueous solubility is a major problem faced during formulation development of new drug molecules. Azilsartan medoxomil (AZ) is an antihypertensive agent and is a good example of the problems associated with low aqueous solubility. Azilsartan medoxomil is practically insoluble in water. Hence, purpose of this research was to enhance the solubility of AZ by using the concept of mixed hydrotropy. Initially, solubility of AZ was determined individually in sodium acetate, sodium citrate, urea and sodium benzoate at concentration of 10, 20, 30 and 40% w/v solutions using purified water as a solvent. Highest solubility was obtained in 40% sodium benzoate solution. In order to decrease the individual hydrotrope concentration mixed hydrotropic agents were used. Highest solubility was obtained in 5:20:15 ratio of urea + sodium acetate + sodium benzoate. This optimized combination was utilized in the preparation of solid dispersions by using distilled water as a solvent. Solid dispersions were evaluated for X-ray diffraction, differential scanning calorimetry and Fourier-transform infrared to show no drug-hydrotropes interaction has occurred. This solid dispersion was compressed to form tablets. Dissolution studies of prepared tablets were done using USP Type II apparatus. The batch F6 tablets show 92.79% cumulative drug release within 45 min. It was concluded that the concept of mixed hydrotropic solid dispersion is novel, safe and cost-effective technique for enhancing the bioavailability of poorly water-soluble drugs. The miraculous enhancement in solubility and bioavailability of Azilsartan medoxomil was clear indication of the potential of mixed hydrotropy to be used in future for other poorly water-soluble drugs in which low bioavailability is a major concern.

Keywords: Azilsartan medoxomil, mixed hydrotropy, solid dispersions.