Comparison of the Effect of Bioadhesive Polymers on Stability and Drug Release Kinetics of Biocompatible Hydrogels for Topical Application of Ibuprofen

Abstract The study is focused on formulation of biocompatible hydrogels with a poorly soluble drug ibuprofen (5%) and comprehensive evaluation and comparison of effect of different bioadhesive polymers on their suitability for application on skin, physical stability during the accelerated and natural aging tests (by performing centrifugation test, light microscopy, differential scanning calorimetry, rheological and pH measurements), and in vitro drug release kinetics. Hydrogels, formulated with xanthan gum 1% (XIB), sodium carboxymethylcellulose 5% (CMCIB), poloxamer 407 16% (PIB), and carbomer 1% (KIB), were soft pseudoplastic semisolids with thixotropy and biocompatible pH. The type of the polymer significantly affected apparent viscosity of the hydrogels and miscibility rate with artificial sweat, their physical stability, and shape, size, and aggregation of the drug crystals and degree of crystallization. The drug release in all investigated hydrogels was diffusion-controlled in accordance with the Higuchi model and sustained for 12 h, with the drug release rate and the amount of drug released depended on the polymer. The described formulation approach enabled discrimination of the hydrogels with unsatisfactory application properties (CMCIB) and physical stability (KIB), and selection of the hydrogel with promising characteristics in terms of all investigated aspects (XIB) which could be considered for further evaluation.