Design and Optimization of Transethosomal Drug Delivery Systems for Ritonavir: Comparative Evaluation, Characterization, and Release Kinetics

Abstract

The present study focused on the characterization and microencapsulation of Eperisone hydrochloride to develop sustained release formulations. The drug’s melting point was determined using the capillary method (183.0 ± 0.6 °C) and validated by DSC (183.5 °C), confirming its thermal stability and purity. FTIR analysis established drug identity and compatibility with Amberchrom resins, with characteristic peaks observed for functional groups such as N–H, C–H, C=C, C–N, and C–O, and no evidence of chemical interaction in drug–resin complexes. Microencapsulation was performed using the O/O method, yielding high drug content recovery (49.00–49.58 mg) and encapsulation efficiencies above 98%, demonstrating reproducibility and minimal drug loss. Particle size analysis showed uniformity across formulations (198.5–206.5 µm), ensuring consistent release behavior. The extent of coating varied from 4.8% to 20.6%, directly influencing drug release rates. In vitro release studies revealed that higher polymer concentration (20% Eudragit RS100) and PEG 400 plasticizer slowed drug release, while increased rotation speed (1500 rpm) enhanced release due to thinner coatings. Kinetic modeling indicated that most formulations followed zero order kinetics, while others aligned with Korsmeyer–Peppas or first order models, confirming diffusion controlled mechanisms. Among all formulations, F4 (20% Eudragit RS100, 10% PEG 400, 500 rpm) exhibited the most controlled release profile, consistent with sustained release objectives. Overall, the study demonstrated that formulation parameters significantly affect drug release, and F4 was identified as the optimal batch for achieving effective sustained delivery of Eperisone hydrochloride