HYPROMELLOSE AND CARBOMER INDUCE BIOADHESION OF ACYCLOVIR TABLET TO VAGINAL MUCOSA

The present research indicates fabrication of an “economic” controlled release bioadhesive vaginal tablets containing acyclovir using only two polymers; Carbopol 934P (as bioadhesive agent) and HPMC K15 (as rate retardant) to provide therapeutic effectiveness for 12 hr duration. The tablets were prepared by direct compression method. The tablets and their constituent materials were evaluated in terms of micromeritics, pharmacopoeial test, and manufacturing parameters. The release mechanism(s) were also elucidated based on various kinetic models. The characteristics were found to be following: average weight of tablets (355-364 mg); drug content (98.91-101.32%); thickness of the tablets (3.21–3.25 mm); surface pH of the tablet formulation (4.41-4.65), hardness of the tablets (5-6 Kg/cm2) and the friability of the batches was less than 1%. Formulation F7 expressed the higher swelling index owing to the higher concentration of HPMC K15 and carbapol 934P. The drug transport mechanism(s) followed non-Fickian diffusion which coincides with swelling erosion mechanism. The drug release process was observed to be governed by two processes; diffusion as well as erosion (often represented as anomalous diffusion). The current study indicated that the hydrophilic matrix tablet of acyclovir, formulated employing only hypromellose and carbomer can successfully be employed as twice daily, very economic bioadhesive vaginal controlled release dosage form. The formulation was found to be suitable with respect to bioadhesive and sustained release characteristic.