Effect of Gellan Gum on the Properties of Collagen-HPMC Freeze-Dried Hydrogels for Mucosal Administration

Mucosal drug delivery is gaining attention for its ability to provide localized treatment with reduced systemic side effects. The vaginal route has been proven effective for managing gynecological conditions, though it poses certain limitations. Biopolymers can help overcome these challenges by enhancing therapeutic efficiency and offering beneficial properties. This study aimed to develop and evaluate hydrogels and their freeze-dried forms (wafers) based on collagen, hydroxypropyl methylcellulose, and gellan gum. Initially, a collagen gel was obtained by extraction from calfskin, which was brought to a concentration of 1% and a physiological pH with 1 M sodium hydroxide solution. This gel was combined with either 2% hydroxypropyl methylcellulose gel, 1.2% gellan gum gel, or both, in different proportions. Thus, five mixed hydrogels were obtained, which, along with the three individual gels (controls), were lyophilized to obtain wafers. Furthermore, the hydrogels were assessed for rheological behavior, while the collagen structural integrity in the presence of the other biopolymers was evaluated using circular dichroism and FT-IR spectroscopy. The wafers were characterized for morphology, wettability, swelling capacity, enzymatic degradation resistance, and in vitro biocompatibility. All hydrogels exhibited non-Newtonian, pseudoplastic behavior and showed collagen structure preservation. The wafers' characterization showed that gellan gum enhanced the hydrophilicity and enzymatic stability of the samples. In addition, the extracts from the tested samples maintained cell viability and did not affect actin cytoskeleton morphology, indicating a lack of cytotoxic effects. This study emphasizes the importance of evaluating both the physicochemical properties and biocompatibility of biopolymeric supports as a key preliminary step in the development of vaginal drug delivery platforms with biomedical applications in the management of gynecological conditions.