Comparison of the Release Kinetics of a Natural Drug-active Extract from Mangifera Indica Leaves Impregnated Into Thermoplastic Polyurethane and Polylactic Acid by Supercritical Fluids

Abstract

The use of pharmacoactive polymeric devices has experienced significant growth in recent years due to their ability to increase the efficacy of treatment and acceptance by the body. Among the natural active principles, those recovered from waste from other industries stand out. In addition to participating in the circular economy, some of these by-products have very interesting properties to be used in biomedicine. However, the challenge in this field is to introduce these active principles into polymers in the most efficient and least polluting way possible. In this sense, one of the techniques with the greatest impact is the use of supercritical fluids. In this work, the supercritical impregnation of two biomedical polymers was studied comparatively: polylactic acid (PLA) and thermoplastic polyurethane (TPU). The impregnated active ingredient was Mangifera indica leaf extract (MLE), which has demonstrated antioxidant, antimicrobial, and anti-inflammatory capacities, and proangiogenic, antiproliferative, and anti-apoptotic effects on colony-forming endothelial cells. The results obtained expose the potential of the polymers studied in the field of biomedicine due to the acquired bioactivity of both polymers after the process, which was verified by measuring the antioxidant capacity. Better loads have been obtained in TPU compared to PLA. Both polymers exhibit diffusion-based release kinetics, in which a rapid release is observed in the early moments followed by a much slower release. However, PLA seems to release a greater proportion of its impregnated extract than TPU in less time, which is interesting to determine the different applications that each polymer can have.