Optimization of metronidazole SR buccal tablet for gingivitis using genetic algorithm

Gingivitis is a condition that needs sustained concentration of antibiotic locally over extended period of time. The current study aimed to formulate and evaluate the sustained and localized release of metronidazole (MTZ) as mucoadhesive buccal tablet containing hydroxypropylmethyl cellulose (HPMC), Carbopol 940® (CP), carboxymethylcellulose (CMC) and ethyl cellulose (EC) as mucoadhesive polymers. Tablets were directly compressed with proportions of polymeric blends (F1-F16). The results indicated that weight variation (249±2.10mg) and friability (0.21%) were within USP compendial limits. Maximum mucoadhesive strength and time were depicted by F1 and F14 which were 28.47g and 12hr respectively. Formulations, except F4, were within physiological pH limit. Maximum swellability index (261.9%) was exhibited by F16, at 8 hr, containing highest concentration of CP, HPMC and additional CMC. For in vitro release, the pre-set 8 hr complete release were shown by formulations, F15 and F16 which were 100% and 97%, respectively. Genetic algorithm was applied on the attributes to optimize polymeric response in accordance with desirability. The software predicted composition (F17) was tested which revealed that physical characteristics were in accordance with the compendial standards. The release kinetics, evaluated through DDsolver⌖, suggested that release of MTZ followed non-Fickian diffusion type in Korsmeyer-Peppas model. Therefore, MTZ, if delivered as mucoadhesive buccal formulation (F17) containing amounts (mg) of CP (16.4), HPMC (78.7), CMC (8.3) and EC (10.5) will simulate satisfactory release i.e. 96% at 8 hr in simulated buccal fluid.