Development of a mucoadhesive dosage form for vaginal administration.

The antimycotic imidazole derivative clotrimazole is employed locally for the treatment of genitourinary tract mycotic infections and is formulated as creams, foams, tablets, gels, irrigations, or pessaries. In this study, a new dosage form was developed by including bioadhesive polymers (polycarbophyl, hydroxypropylmethylcellulose, and hyaluronic sodium salt) into pessaries made of semisynthetic solid triglycerides. These polymers hold the delivery systems in the vaginal tract for a few days without any toxic effects or important physiological modifications, prolonging the permanence of the drug on the vaginal mucosa. Technological controls (compatibility with differential scanning calorimetry [DSC] studies, particle size analysis, and liquefaction time test) and biopharmaceutics studies for the evaluation of the release of the drug from the dosage form and of the bioadhesive properties were carried out. Moreover, a new test for the evaluation of the permanence of the drug in a simulated application site was developed from a modification of the Satnikar and Fantelli method for the evaluation of the liquefaction time of rectal suppositories. This test simulates the physiological vaginal condition and verifies the efficiency of the polymers in prolonging the permanence of the dosage form in the location where it is applied. The technological controls demonstrated that the presence of the polymers did not have an influence on the characteristics of the pessaries. On the other hand, there was an improvement in adhesivity of the pessaries in the in vitro adhesion test and prolonging of the liquefaction time in the liquefaction time test in the presence of mucoadhesive polymers, which increased with increasing polymer concentration. The presence of the mucoadhesive had a large influence on the permanence of the drug in the simulated application site because it modified the distribution of the drug along the simulated application site. In conclusion, the developed new formulations showed good technological and adhesion properties and the capacity of hold the dosage form in the target site. Among the employed bioadhesive polymers, the best behavior in the performed test was by polycarbophyl at its maximum concentration.