Studies on inclusion complex as potential systems for enhancement of oral bioavailability of olmesartan medoxomil

Background: Olmesartan medoxomil (OLM), an anti-hypertensive agent administered orally, has absolute bioavailability of only 26% due to the poor aqueous solubility (7.75 μg/ml). Inclusion complexation with cyclodextrins (CD) has been reported to increase the aqueous solubility of various compounds. Aim: The present investigation aimed to enhancing the oral bioavailability of OLM by inclusion complexation with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). Materials and Methods: The inclusion complexes with HP-β-CD were prepared using two different methods, viz., physical mixture and kneading. The prepared complexes were characterized for various parameters such as drug content, aqueous solubility, dissolution study, in vitro diffusion, intestinal permeability and stability study. The formation of the inclusion complex was confirmed by differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy. Results: The solubility, dissolution, diffusion rate, and intestinal permeability of the prepared complexes were found to be significantly higher than that of the plain drug. Among the two methods used for formation of inclusion complex, KN method gave higher solubility rates and hence is a better method when compared with PM. Conclusion: The approach seems to be promising in improving the oral bioavailability of OLM.