Influence of the chemical composition and structure design of electrospun matrices on the release kinetics of Aloe vera extract rich in aloin

The release kinetics of bioactive agents from electrospun matrices is governed by several factors, such as the chemical composition and design of the release device. In this work, three different chemical formulations and two different product designs were developed to control the release of Aloe vera extract rich in aloin to skin lesions. The kinetics of aloin release from single layer electrospun materials formulated with polymers with different biodegradation rates (isolated PCL and PCL blended with PLLA or PDLG) was analyzed and compared to the behavior of a three-layer sequential electrospun PCL matrix in which only the intermediate layer contained the A. vera extract (PCL SW). The multilayered structure with the physically confined bioactive agent layer had the purpose then of both modulating aloin release and also of protecting it from direct light exposure. Thin films were obtained, all presenting high potential to be used as wound dressing components, with thickness values of 0.13-0.26 mm and homogeneous fibrous microstructure, capable of absorbing from 1.06 to 2.88 g of phosphate buffered saline per gram of matrix. The films were stable in the same buffer, showing a maximum mass loss of less than 8% after 7 days. The biomaterials presented tensile strength of 0.64-1.37 MPa and elongation at break of 277-375%. The most striking difference in behavior was in the release kinetics, which was much more controlled with the PCL SW structure than with the others, in which marked burst effect was observed. In this film, the release mechanism was associated with the diffusion of the bioactive agent, having also contributions from the electrospun matrix relaxation and dissolution. (c) 2020 Elsevier Ltd. All rights reserved.