Kinetic release mechanism of the composite poly(ᴅ,ʟ-Lactide)/natural clay nanoparticles loaded with Moringa Oleifera leaves extract

Abstract

Nanoparticulization provides distinctive advantages such as controlling the drug release rate and designing to reduce the side effects of the drug to the human body. However, the sustained release of Moringa Oleifera (MO) bioactives remains challenging, as the kinetic mechanism from natural clay/PLA nanoparticles is not yet fully elucidated. This study investigates the kinetic release and mechanism of composite poly(ᴅ,ʟ-lactide) (PLA)/natural montmorillonite (MMT) nanoparticles (NPs) loaded with MO leaf extract through in vitro testing. To investigate the drug release profile, MO leaves need to be extracted by Soxhlet extraction and freeze-dried. The total phenolic content (TPC), total flavonoid content (TFC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, and 2,2’-azino-bis-[3-ethylbenzothiazoline sulphonate] (ABTS) radical cation decolorization assay for MO extract are 372.81 mg GAE/g, 90.89 mg QE/g, 91.68% and 85.1%, respectively. For MO powder, the TPC, TFC, DPPH, and ABTS are 373.37 mg GAE/g, 92.15 mg QE/g, 94.02%, and 89.42%, respectively. Freeze-dried MO powder was encapsulated in PLA/MMT to sustain its release at varying pH levels (2, 5.5, and 7.4). Fixed parameters included an aqueous-to-organic phase ratio of 10, a stirring speed of 1200 rpm, 1 wt/wt% MMT, and 5 wt/wt% MO. MO loading and encapsulation efficiencies were 12% and 16% for PLA-loaded MO NPs and 74% and 84% for composite PLA/MMT-loaded MO NPs, respectively. The kinetic release mechanisms of these PLA/MMT-loaded MO NPs were then validated using the zero-order, first-order, Higuchi, and Korsmeyer-Peppas models, respectively. Characterization via XRD, FTIR, and SEM revealed monodispersed spherical NPs with average sizes of 200 nm, 270 nm, and 240 nm for PLA blank NPs, PLA-loaded MO NPs, and PLA/MMT-loaded MO NPs, respectively. The release mechanism followed Fickian diffusion, and the drug release profile aligned with the Korsmeyer-Peppas model. This work provides a potential basis for the synthesis, characterization, and kinetic release processes needed to create sophisticated and sustained pharmacological formulations.