Supercritical CO2 particulate leaching and impregnation: A new strategy for customized electrospun mats loaded with an antiviral drug

This research introduces a new method for impregnating active compounds into electrospun biomembranes, significantly improving drug loading by exploiting the unique properties of CO2 under supercritical conditions. The innovative approach involves the creation of customized electrospun matrices, with stearic acid acting as a porogen with controlled crystal dimensions (≤ 0.500 µm) deposited at fixed time intervals during the fiber deposition by electrospinning. The electrospun zein mat, loaded with the porogen agent crystals, undergoes a novel single-stage supercritical carbon dioxide-based process named Supercritical Leaching and IMpregnation (SLIM). This process involves the simultaneous removal of the porogen agent, the purification of residual solvent traces from the membranes, and the loading of the drug (in this case, acyclovir) by impregnation. The impregnation kinetics, determined at 200 bar, show that an increase in contact time leads to higher acyclovir loadings, reaching maximum values of 22.4 % wacyclovir/wmembrane at 50 °C. In contrast, the loading of acyclovir by impregnation on the electrospun mat without the use of a porogen was only 1.6 % wacyclovir/wmembrane. Therefore, the use of a suitable porogen agent in the SLIM process proposed in this paper led to the creation of a structure with controlled-size pores and a high drug loading. This promising development has the potential to revolutionize drug delivery systems production technologies, offering new possibilities for controlled and sustained drug release devices production.