Formation of Amorphous Telmisartan Polymeric Microparticles for Improvement of Physicochemical Characteristics

Abstract

In order to improve solubility and dissolution rate of poorly aqueous soluble telmisartan, its amorphous polymeric microparticles with PVP K30 were prepared with or without aid of adsorbent (Aerosil200/Sylysia350) using spray-drying technique. The pure drug and formulations were evaluated for their morphology, particle size, aqueous solubility, and in vitro drug release. Solid state characterization of pure drug and microparticles was carried out by Fourier transform infrared spectroscopy (FTIR), x-ray powder diffraction (XRPD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). FTIR indicated hydrogen bonding interaction with an absence of any other chemical interaction between drug and excipient. The results of DSC and XRPD revealed transformation of crystalline drug to amorphous form which was confirmed by SEM. Significant solubility and dissolution enhancement was observed for all polymeric microparticles over pure drug and spray-dried pure drug. This enhancement was attributed to the wetting effect of polymers, altered surface morphology with micronization and decreased crystallinity of drug particles.