Optimisation of the controlled release of valsartan via cellulose acetate butyrate and poly(butylene succinate) microspheres: Influence of formulation conditions

This study investigates the formulation of valsartan-loaded cellulose acetate butyrate (CAB) microspheres, prepared via solvent evaporation microencapsulation, to evaluate their in vitro release behavior and the influence of formulation parameters. The study examined the effects of stirring speed, stabilizers and matrix materials on particle size and drug release. Increasing stirring speed reduced particle size but also led to higher valsartan loss, reducing encapsulation efficiency. Using the surfactant polylactic acid resulted in smooth, spherical and porous microspheres that enhanced controlled release. In contrast, using Tween 80 led to irregular particles with rough surfaces and larger pores that accelerated drug release. Including poly(butylene succinate) in the matrix resulted in smaller microparticles forming and a significantly higher rate of valsartan release. These findings emphasize the importance of optimizing formulation parameters and excipients to control drug release characteristics and enhance drug delivery system performance.