Effects of Absorbent on the Dissolution Rate of PEG-Based Solid Dispersions Containing Poorly Water-Soluble Drug

Abstract

The aim of this research was to investigate the effects of absorbents on solid dispersions (SDs) to improve the solubility of isradipine (IS). Polyethylene glycol 6000 (PEG 6000) was applied to investigate physical structure and improved dissolution rate of IS under SD form. Aerosil® 200 was used as a moisture absorbent to maintain the dryness and free-flow of powders and granules during storage. SDs were prepared by melting method at various ratios of drug and polymers. Dissolution rates of SDs were tested in simulated gastric fluid (buffer pH 1.2) and simulated intestinal fluid (buffer pH 6.8). High-performance liquid chromatography (HPLC) was utilized to determine concentration of IS after dissolution test. Structural behaviors of drugs and SDs were characterized by Power X-ray diffraction (PXRD) and molecular interactions between drug and carriers were analyzed by Fourier Transform Infrared spectroscopy (FTIR). A transformation of crystalline form into amorphous state of SDs and an intermolecular bonding were observed. Aerosil® could be considered as a pertinent absorbent to assist the carrier in increasing the dissolution rate of poorly water-soluble drugs.