Once daily bioadhesive vaginal clotrimazole tablets: design and evaluation

In this study, a bioadhesive dosage form of clotrimazole was designed using a combination of bioadhesive polymers Carbopol 934P, sodium carboxymethyl cellulose and sodium alginate in different ratios. The bioadhesive strength was evaluated by measuring the force required to detach the tablets from porcine vaginal mucosal membrane. The strong interaction between polymer and mucus lining of the tissue helps increase the contact time and permits localization of activity. Carbopol 934P showed maximum bioadhesion and required maximum force for detachment; the force required for detachment was directly proportional to its content. The formulations were tested for their swelling behavior using the agar gel plate method. The swelling index was a function of the concentration of the hydrophilic polymer and the formulations containing Carbopol 934P and sodium carboxymethyl cellulose were found to swell to a greater extent than those containing Carbopol and sodium alginate. In vitro release studies showed that the batch consisting of 2:1 ratio of Carbopol 934P/sodium alginate (batch C3) released clotrimazole over 24 h. The similarity factor showed that the dissolution profiles of fresh and aged tablets were similar, suggesting good stability of vaginal tablets prepared using a combination of Carbopol 934P and sodium alginate.