Preparation and characterization of valsartan-loaded polyoxalate microspheres: In vitro release profiles

Valsartan, a selective angiotensin II type 1 receptor (AT1R) antagonist, has a high bioavailability. Hydrophobic polyoxalate has been suggested for use in biodegradable medical devices such as absorbable sutures and controlled release applications. In this study, we developed valsartan-loaded polyoxalate microspheres by varying the polyoxalate molecular weight, surfactant content, and initial drug loading rate. The morphology of the valsartanloaded polyoxalate microspheres was evaluated by scanning electron microscopy and the hydrolysis kinetics of polyoxalate were investigated. The influences regarding the preparation parameters were evaluated with respect to the release of valsartan. The results demonstrated that the release behavior can be effectively controlled by the preparation conditions.