Sodium alginate based fast swelling nanogels for solubility enhancement of chlorthalidone; synthesis,...

Purpose of the study was to enhance the solubility of chlorthalidone, poorly soluble diuretic that has been the used for lowering high blood pressure for the past half-century. Solubility is a challenge for approximately 90% of drug candidates. Chlorthalidone is BCS Class IV drug whose poor solubility needs to be improved in order to optimize its efficacy. Using a free radical polymerization technique, sodium alginate-based nanogels were formulated for enhancing solubility of chlorthalidone. The evaluation of various characteristics of nanogels was done by structural characterization, drug loading, swelling, sol-gel transition,in-vitrorelease, solubility, and toxicity tests. Fourier transform infrared (FT-IR) spectroscopy revealed characteristic peaks of the primary raw materials and polymeric nanogels. The FT-IR spectra of the chlorthalidone-loaded nanogels suggested discrete drug peaks confirming successful drug loading. The system's amorphous nature and thermal stability were indicated by powder x-ray diffractometry and thermal analysis. The scanning electron microscopy indicated a well-defined porous structure. The size of the nanogels was determined by zeta size analysis to be 189 ± 18.35 n·m. The solubility enhancement factor demonstrated the potential for improved solubility of the poorly soluble drug. The resulting biocompatible nanogels could be used to improve the solubility of hydrophobic drugs.