Development of amphotericin B inclusion complex formulation in dissolvable microarray patches for intravaginal delivery.

Background: Amphotericin B (AMB) is a drug used to treat vulvovaginal candidiasis (VVC), which is a fungal infection affecting the vagina and vulva. Nevertheless, the substance's limited capacity to dissolve in water leads to poor absorption when taken orally, hence diminishing its therapeutic efficacy. In order to address this limitation, β-cyclodextrin (βCD) was used to create AMB in the form of an inclusion complex.

Objective: This study aims to enhance the solubility and bioavailability of AMB by formulating it into an inclusion complex with βCD. Subsequently, we developed dissolvable microarray patches (DMP) as a novel drug delivery system, optimizing the formulation for improved retention, penetration, and controlled release of AMB.

Methods: The stability of the AMB-βCD inclusion complx (IC) structure has been confirmed by employing molecular docking studies. The formulation of DMP involved the incorporation of IC with polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). The mechanical strength, ability to be inserted, and propensity to irritate Amphotericin B-Inclusion Complex-Dissolvable Microarray Patches (IC-DMP) were evaluated by laboratory experiments utilizing the porcine vaginal mucosal layer. Further investigations, such as Differential Scanning Calorimetry (DSC), were performed to assess the physicochemical characteristics of the IC.

Results: The solubility of the pure medication was greatly enhanced up to fourfold by the inclusion complex. The assessment of IC-DMP exhibited exceptional mechanical robustness and insertion abilities, with no indications of discomfort. Among the formulas tested in ex vivo vaginal kinetic experiments, Formula F3 had the most effective retention in the porcine vaginal mucosal layer. It had an AUC value of 208.02 ± 0.33 h.µg/cm and the highest C value of 20.05 ± 0.06 µg/cm. Therefore, Formula F3 was the most efficient formula in terms of vaginal drug delivery.

Conclusion: The integration of IC into the DMP system significantly enhances the solubility and bioavailability of AMB, facilitating its absorption in the circulatory system when applied intravaginally for vulvovaginal candidiasis treatment. These promising initial findings support further clinical evaluation of this novel drug delivery system.