Formulation, solid state characterization and enhancement of dissolution rate of olmesartan medoxomil by polyvinyl alcohol-polyethylene glycol graft copolymer based nanoparticles

Abstract

The objectives of present investigation were to prepare and evaluate nanoparticles of Olmesartan medoxomil (OLM) by a precipitation method using polyvinyl alcoholpolyethylene glycol graft copolymer (Kollicoat IR) and to investigate the effect of stirring speed & time on particle size. Particles were characterized for drug content, FTIR, zeta potential (ZP), particle size distribution (Dynamic light scattering), differential scanning calorimeter (DSC), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), solubility, in vitro release and stability studies. All batches showed drug content in range of 93.24 ± 0.96% to 99.91 ± 0.98%, particle size in range of 136.3-188.9 nm. As stirring speed increased particles of reduced size obtained and vice versa. ZP values of formulations were from -2.28 mV to -17.90 mV & comply with requirement of ZP for stability. Solubility results indicated improvement in solubility of formulations. PXRD analysis showed particles were in same crystalline state as raw OLM. Particle exhibited enhanced dissolution compared to raw material due to reduction in particle size, increased surface area & solubility. When formulated in tablets showed improvement in dissolution, compared to marketed formulation, anti solvent precipitation method is promising tool to prepare OLM particles by using Kollicoat IR as a polymer, for enhancement of solubility, dissolution velocity of OLM.