Physicochemical study of mucoadhesive polymers and their interactions with mucin

Solid drug dosage forms applied directly to the mucous membrane are becoming very popular because they allow to prolong the drug release for several hours and ensure maintainance of the optimal therapeutic level. This effect is possible due to the presence of mucoadhesive polymers. The mutual entanglement of polymer and mucin chains leads to form a gel structure which is a reservoir for the drug. Generally, the mucoadhesive forms contain hydrophilic polymers, such as polycarbophil, carbomer, chitosan, or cellulose derivatives (HPMC, HEC, etc.).

Scientific papers indicate that selecting the appropriate ratio of the polymers can extend the drug release, enhance the repeatability of the release profiles, improve the mucoadhesive properties of the material surface, and improve drug transport to the mucosa. Therefore, it is important to look for a correlation between the composition of the mucoadhesive carrier and its surface properties. Consequently, the wettability of polymer matrices, the degree of their swelling, the SFE value, and the mucoadhesion force are crucial for designing oral carriers and predicting their effectiveness in vivo. In our research, we measured the swelling and the contact angle on the polymer surface by the sessile drop method using various simulated biological fluids, water, and diiodomethane. The correlation between the physicochemical properties and release profiles obtained for antifungal drugs were evaluated.

Moreover, to explore the interactions between the polymer and mucin in the cell membrane environment, studies were carried out using the Langmuir monolayer technique. The obtained results allowed to better understand the mucoadhesion process and confirm the existence of interactions between mucin, mucoadhesive polymers, and model biological membranes. We have shown that these interactions depend on the type of mucoadhesive polymers, pH, and presence of mucin.