Encapsulation of water-soluble drugs in Poly (vinyl alcohol) (PVA)-microparticles via membrane emulsification: Influence of process and formulation parameters on structural and functional properties

Drug-loaded poly (vinyl alcohol) (PVA)-based microparticles have been synthetized by using membrane emulsification and chemical cross-linking. The encapsulation of two water-soluble molecules, catechol (CA) and diclofenac sodium (DS), has been considered as case studies. PVA hydrogels have been recognized as promising biomaterials and suitable candidates for drug delivery. However, the encapsulation of hydrophilic, low molecular weight drugs in particulate materials is currently an ambitious goal. The purpose of this work was to develop high-drug loading systems for hydrophilic molecule delivery based on uniformly distributed particulate carriers. Membrane emulsification has been used as advanced manufacturing method to design drug-loaded PVA microparticles with target properties in terms of particle size, particle size distribution, structure and functional activity. A special emphasis is laid on the important factors that contribute to tune the structured properties of microparticles, encapsulation efficiency/drug loading and drug delivery. In particular, the influence of emulsification method (membrane and homogenizing approaches), phase compositions (PVA concentration, drug concentration, physicochemical properties of drug), cross-linking reaction conditions (cross-linking agent concentration, acidic media) has been studied. Finally, the potential of PVA-based microparticles as drug delivery carriers as well as their in vitro cytotoxicity have been evaluated.