Mucoadhesive nanostructured systems for vaginal administration: Differential scanning calorimetry, in vitro mucoadhesion and syringeability.

Mucoadhesive systems such as hypericin (HYP)-loaded nanostructured lipid carrier (NLC) dispersed into in situ hydrogel (HG), could increase its residence time in the vaginal environment. The objective was to develop mucoadhesive systems for vaginal administration of HYP. NLC-HYP was prepared by sonication (35% amplitude, 5 minutes) and dispersed in HG, obtained by magnetic stirring. Differential scanning calorimetry, in vitro mucoadhesion and syringeability of systems were determined. HG and NLC-HYP_HG showed defined endothermic peaks (55.35 °C, 60.15 °C and 298 °C) characteristic of the components polyoxyethylene stearate, poloxamer 407 and HYP. Mucoadhesive force work values of the systems (0.025 and 0.029 N.sec, respectively), showed that probably the chemical groups of chitosan and polaxamer 407 interacted with the vaginal mucosa through hydrogen bonding. The work of syringeability values (10.55 and 15.74 N.mm, respectively), showed ease of administration of the systems. The results demonstrate that mucoadhesive systems are promising alternatives for vaginal administration.