Vasorelaxant effect of standardized extract of Cecropia glaziovii Snethl encapsulated in PLGA microparticles: In vitro activity, formulation development and release studies

In this study, the standardized dry extract of C. glaziovii (SDE) provided a significant vasorelaxant effect after contractions induced by phenylephrine in rat aortic rings in an endothelium-dependent manner, confirming that endothelial factors are needed to stimulate this response. A vasorelaxation close to that of acetylcholine was achieved, justifying the development of new formulations for this plant material. In this context, microparticles were selected to encapsulate SDE and the double emulsion technique was considered because of the hydrophilic nature of plant material. Two experimental designs were applied. Firstly, the effect of formulation parameters on particle size, size distribution and encapsulation efficiency (EE) was evaluated. As low EE was achieved, the effect of the osmotic pressure of the external phase was evaluated in a second experimental design. The presence of the osmotic agent (NaCl) impacted positively on the EE and slower in vitro release profile was obtained, which is desired in controlled release systems. The formation of denser and less porous particle surface, which was identified by SEM analysis, contributes to explain these findings. Microstructures showed to be a promising delivery system for the C. glaziovii SDE considering that a sustained release was achieved.