Formulation and in-vitro/in vivo evaluation of metronidazole suppositories

ABSTRACT

The optimization of metronidazole suppositories has been investigated. 12 different formulations were prepared using 7 fatty bases; namely, Suppocire A, NA 10, AP and BP, Witepsol H15, Estaram H12 and Estaram H15, either alone, in a mixture, or in combination with other excipients such as docusate sodium or Tween. The different formulations were evaluated by the in vitro drug release rate using the non-membrane method, in the BP 88 dissolution apparatus. The release pattern of the drug from formulations containing only the bases showed large differences. The percent drug released after 15 minutes ranged from 6 [in case of Suppocire A] to 100% [in case of Suppocire AP and BP]. The presence of docusate sodium and Tween 80 in formulations prepared with Suppocire A and NA 10 enhanced the metronidazole release. The effect of ageing on drug release from some selected formulations was also studied. The suppository formulation containing only the drug in Suppocire AP was tested in vivo on 8 healthy male volunteers in comparison to the commercial st and ard tablets [Flagyl]. The obtained bioavailability and pharmacokinetic data for both products were nearly similar