Mechanism and Kinetics of Drug Release from Poly(ϵ-Caprolactone) Based Extrudates Prepared By Hot-Melt Extrusion

Abstract

In this study, different types of poly(ϵ-caprolactone) (PCL)-based matrices were prepared by hot-melt extrusion. Methylene blue (MB) was used as a model drug, and various amounts and types of hydrophilic components (polyethylene glycol, PEG or polyethylene oxide, PEO) were added to the extrudates as release rate modifiers. The drug release mechanism and kinetics from these extrudates were investigated. Scanning electron microscopy (SEM) and micro-Fourier transform infrared spectroscopy (micro-FTIR) results revealed the dissolution of the hydrophilic components (PEG or PEO) during the drug release, and in-vitro release tests exhibited the tailorable release behavior of MB from the PCL/hydrophilic components. Based on the experimental results, it was speculated that the release kinetics of MB from the PCL/hydrophilic components was a combination of diffusion and dissolution models.