مصطفي سعيدي

The capability of drug release through a hydrogel network with a semi-interpenetrating (Semi-IPN) structure has found widespread applications in medical fields. In this study, the biocompatible an‎d biodegradable polymer Chitosan was employed to form a chitosan hydrogel network with single responsiveness to pH, using various concentrations of glycyrrhizic acid as a novel crosslinking agent. Subsequently, a temperature-sensitive copolymer, poly(N-isopropyl acrylamide-co-acrylic acid), was polymerized in an aqueous medium in the presence of crosslinked Chitosan, leading to the formation of a Chitosan Semi-IPN structure with dual sensitivity to both temperature an‎d pH. These synthesized chitosan hydrogels including both the single an‎d dual responsive were investigated for the controlled release of Gallic acid, with potential applications in skin-related therapies. FTIR analysis confirmed the formation of hydrogel bonds through the creation of amide linkages between the amino functional groups of chitosan an‎d the carboxylic acid groups of Glycyrrhizic acid. This analysis also verified the incorporation of the temperature-sensitive copolymer into the Semi-IPN Chitosan network. Thermogravimetric analysis (TGA) revealed three thermal degradation peaks at 249 °C, 290 °C, an‎d 379 °C, corresponding to the acrylic acid monomer, N-isopropyl acrylamide monomer, an‎d chitosan polymer, respectively. The simple chitosan hydrogel samples exhibited swelling in the range of 137–455% at room temperature across different acidic environments (pH 4–7). Chitosan showed increased swelling in lower pH values, an‎d the drug release results indicated that this enhanced swelling led to greater release of Gallic acid. Furthermore, the swelling ratio of the Semi-IPN Chitosan hydrogel samples at pH 5.5 an‎d temperatures of 15 °C, 30 °C, an‎d 45 °C ranged from 194% to 413%. As the temperature exceeded the lower critical solution temperature (LCST), a coil-to-globule transition occurred in the copolymer chains within the interpenetrated hydrogel network, resulting in increased swelling. Drug release data for Semi-IPN Chitosan hydrogel showed that at 45 °C, hydrogen bonds between Gallic acid molecules an‎d the Semi-IPN network were disrupted, leading to intensified drug release. Additionally, biological studies demonstrated that the hydrogel samples possessed sufficient biocompatibility, an‎d those loaded with gallic acid exhibited effective anti-bacterial activity, indicating their potential for dermatological applications.

شبكه‌هاي هيدروژلي , كيتوسان , حساسيت يگانه , حساسيت دوگانه , گلي‌سيرهيزيك اسيد , كوپليمر حساس به دما , ساختار نيمه درهم تنيده , رهايش گاليك اسيد

Hydrogel networks , Chitosan , Single responsiveness , Dual responsive , Glycyrrhizic acid , Temperature-sensitive copolymer , Semi-IPN structure , Release of Gallic acid

Mostafa Saeedi

Mohammad Reza Moghbeli