Kinetic analysis of in vitro release profiles of salicylic acid and fluocinolone acetonide from dual delivery systems composed of polymeric nanocarriers and a hydrogel matrix

Abstract

Many research studies have focused on the design of dressing materials that ensure fast and healthy regeneration of the skin while maintaining sterility and delivering active substances at the required time for treatment. In this study, a method for synthesizing a pH/thermosensitive polymeric nanocarrier and its encapsulation with salicylic acid (SA) and fluocinolone acetonide (FA) is reported for the first time. Dual-drug delivery systems comprising a sodium alginate/poly (vinyl alcohol)/aloe vera-based hydrogel matrix and drug-loaded polymeric nanocarriers (T-SA + FA or pH-SA + FA) were obtained and characterized by scanning electron microscopy (SEM) and Fourier-transform infrared (FT-IR) spectroscopy as well as degradation, mechanical, microbiological, and cytotoxicity tests. The swelling degree in water of the base matrix (M) and those of the bio-hybrids M-pH-SA + FA and M-T-SA + FA were in the range of 87–262%, 158–203%, and 87–156%, respectively. Degradation rates were comparable for all the analyzed samples, with values of 40.3%, 44.7%, and 42.5% for the base matrix (M) and bio-hybrid hydrogels M-pH-SA + FA and M-T-SA + FA, respectively. Both bio-hybrids inhibited the growth of different bacteria, such as Staphylococcus aureus and Escherichia coli. Cytotoxicity tests proved that the materials obtained do not show cytotoxic effects and are safe for skin cells. The release of dual drugs from the bio-hybrid system occurred in a prolonged and controlled way, according to the Korsmeyer–Peppas model.