A comparative analysis of PLA and PCL microparticles for hydrophilic and hydrophobic drugs

This study aims to investigate Polylactic Acid (PLA) and Polycaprolactone (PCL) polymers for microencapsulation of hydrophilic and hydrophobic anti-glaucoma drugs using an emulsion-based solvent evaporation technique. Microparticle size was analysed using optical microscopy, while drug-polymer interactions through Dynamic-Light-Scattering (DLS) and Fourier-Transform-Infra-red/Attenuated-Total-Reflection spectroscopy (FTIR/ATR). <i>In vitro</i>, drug release studies were performed to investigate drug encapsulation and release profiles. Spherical microparticles, with particle size 94 ± 6.9 μm for PCL-based and 100 ± 3.74 μm for PLA-based formulation, were obtained. Drug release studies showed 100% release over about 32 days, with encapsulation efficiency (%EE) and drug loading (%w/w) reaching up to 95 and 2.84% for PLA-based and 97 and 2.91% for PCL-based microparticles, respectively. DLS studies reveal an increase in hydrodynamic radius (<i>R_H</i>), which correlates to enhanced drug encapsulation. So, the nature of the drug and polymer significantly impacts drug encapsulation and release, with drug-polymer interactions playing a crucial role alongside experimental parameters.