Influence of Mucoadhesive Polymers on Physicochemical Features and Biocompatibility of Collagen Wafers

The aim of this study was to develop and characterize some freeze-dried wafers based on collagen and two mucoadhesive polymers, namely, hydroxypropyl methylcellulose (HPMC) and Carbomer 940 (CBM). The wafers were obtained by lyophilization of the corresponding hydrogels, which were evaluated by circular dichroism in order to investigate mucoadhesive polymers' influence on collagen's secondary structure. The obtained freeze-dried wafers were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), contact angle measurements, and water uptake capacity. Furthermore, biocompatibility assessment was performed by evaluating the impact of freeze-dried wafer extracts on cell viability, morphology, and migration capacity. Circular dichroism showed more significant changes in the secondary structure of collagen associated with the addition of Carbomer 940. The FT-IR spectra displayed specific peaks for collagen and the two mucoadhesive polymers. SEM images illustrated a microporous structure for both collagen and Carbomer 940, while HPMC displayed a more sheet-like structure. The addition of HPMC increased the thermal stability of collagen, while Carbomer 940 had a negative impact on the samples' thermal stability. Contact angle measurements and water uptake capacity showed good hydrophilicity of the wafers. Except for CBM 100%, all samples supported the viability of human fibroblasts and did not have any inhibitory effect on cell migration capacity, demonstrating good biocompatibility, which is an essential attribute in developing drug delivery supports intended for mucosal applications.