Mucoadhesive oral film based on high methoxyl pectin and phosphated cassava starch incorporated with Calendula officinalis extract

There is growing interest in developing medical products with high biocompatibility and bioactivity. The aim of this study was to develop and characterize a film for topical application, capable of adhering to the oral mucosa and releasing bioactive compounds. The films were formulated using natural ingredients: high methoxyl pectin (HMP) and phosphated cassava starch (PCS), combined with Calendula officinalis extract (CoE). The CoE was obtained through cold maceration of calendula inflorescences. Films were produced using the solvent evaporation technique with varying CoE concentrations (control/without extract; 100 g kg- 1; 200 g kg- 1). HPLC-DAD analysis of the CoE identified its main constituents as cinnamic acid derivatives and flavonols. SEM analysis of the control film demonstrated strong interfacial adhesion between HMP and PCS, resulting in a prolonged disintegration time (107.33 +/- 3.79 min). Furthermore, the control film exhibited noteworthy DPPH center dot free radical scavenging activity (29.20 +/- 2.28 %) attributed to the presence of pectin phenolic compounds. Films incorporated with CoE showed a higher percentage of elongation and mucoadhesiveness, along with a lower tensile force compared to the control. Moreover, the antiradical activity was further enhanced in the films incorporating the extract. Although the CoE exhibited activities against Staphylococcus aureus and Candida albicans, films with CoE did not show inhibition for either microorganism. The release of bioactive compounds over 24 h was 46.8 % for the films with 100 g kg- 1 CoE and 65.7 % with 200 g kg- 1 CoE. Overall, the study suggests that the HMP/PCS film can effectively release phytochemicals and demonstrates potential for use in mucoadhesive oral applications.