KOJIC ACID IN POLYMER-PROTEIN-BASED HIDROGELS FOR SKIN DELIVERY APPLICATIONS

Inflammatory dermatoses include a group of widely incident diseases. However, the development of new treatment methods is still a challenge. Kojic acid (KA), known as tyrosinase production inhibitor, exhibit promising anti-inflammatory properties, which leads to the design of new biocompatible pharmaceutical formulations, such as polymer-protein-based hydrogels. In this sense, the use of chitosan (CS) and sericin (SER) is attractive. Hydrogels were prepared with CS (3%) and different concentrations of SER (1.5%, 3% and 6%) containing 0.1 % KA. Samples physico-chemical and morphological characterization were performed by oscillatory rheology (temperature sweep from 0°C to 50° at 1 Hz, and frequency from 0.1 Hz to 10 Hz at 32.5°C) and scanning electron microscopy (SEM), respectively. Additionally, samples stability was detected after 6 months prepared. Permeation profiles were obtained across skin-model artificial membranes. Results from temperature rheological analysis revealed that all formulations exhibited adequate stability, elasticity, and transition temperatures values (Tsol-gel= 27-30 °C) close to skin temperature surface, even after a long time after preparation. SEM analysis showed the hydrogels’ ability for forming thin films, with smooth or irregular surfaces and presence of pores. In vitro assays indicated the influence of SER concentration on KA permeation parameters, since the flux values were 0.174 ± 0.01; 0.155 ± 0.03 and 0.216 ± 0.02 µg/cm2/h for 1.5; 3 and 6 % SER, respectively. Similarly, permeability coefficients were 2.89.10-4; 2.58.10-4 and 3.59.10-4 cm2/h at 1.5; 3 and 6 % SER. Those data suggest an improvement on KA permeation promoted by CS-SER-based hydrogels, associating adequate structural stability after 6 months. All those factors pointed out CS-SER-based hydrogels as promising systems for KA skin delivery