Microbiological assay method for the determination of rifampicin in rat plasma: Application in pharmacokinetics

Prashanth M. Kamath, Dinesh B. Shenoy, Karki Roopa, N. Udupa, Kotian Mohan

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2 Citations (Scopus)


A simple, accurate and sensitive microbiological assay method for estimation of rifampicin in rat plasma was developed employing Kirby Bauer disc diffusion technique. This method was applied for pharmacokinetic evaluation of rifampicin given as subcutaneous injection at 10 mg/kg dose level. It was observed that the method was sensitive upto nanogram level of plasma rifampicin, lowest detectable limit being 10 nanograms. The method was rapid with incubation period of 18h at 37°C and also was reproducible with a maximum inter-assay and intra-assay coefficient of variation 3.5%. The difference in the plasma concentrations estimated was not significant (P<0.05) both within and between assays. Besides this, it was economical compared to the High Performance Liquid Chromatographic procedure with minimal sample preparation and processing. The microbial assay could be successfully employed in pharmacokinetic studies of rifampicin. It would be a more meaningful method especially for drug in the formulations, as quantification is based on the pharmacological activity rather than chemical nature of the drug like any other instrumental method of analysis in which, change in potency of the antibiotic cannot be detected.

Original languageEnglish
Pages (from-to)307-311
Number of pages5
JournalIndian Drugs
Issue number5
Publication statusPublished - 05-1999

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Pharmaceutical Science
  • Drug Discovery


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