Controlled Release of a Hydrophobic Fluorescent Molecule From Polyvinyl Alcohol/Polycaprolactone Composite Thin Films

Drugs with low water solubility comprise a significant proportion of pharmaceutical compounds. To control the release of these drugs, polymer thin-film formulations with a physical hydrophobic barrier layer do not provide ideal release profiles. In this study, polymer carriers with hydrophilic polyvinyl alcohol (PVA) as the barrier layer are developed, and investigated the effect of the PVA film thickness on the release of hydrophobic molecules. Instead of an aqueous system, an oil-based system is used to measure membrane permeability, and Nile Red is used as the hydrophobic model drug. PVA thin films are prepared with polycaprolactone as the supportive layer, which retained their permeability. In the limited thickness range investigated, PVA thin films exhibited thickness-dependent permeability toward the hydrophobic model drug.