Micrococcus luteus was employed for the assay of rifampicin in fixed-dose combinations (FDCs) of anti-tubercular drugs containing rifampicin, isoniazid, pyrazinamide and ethambutal. The microbiological assay was compared with spectrophotometric assay for estimation of rifampicin in the FDCs as well as in dissolution studies of the FDCs. The microbiological method was found to be more sensitive ...

We describe a radioimmunoassay for measuring clindamycin in serum extracts that is more accurate than the microbiological assay because of the minimal response of the matabolite, N-demethylclindamycin. The assay is not affected by the presence of other antiobiotics. As described it is as sensitive as the microbiological assay, but can be made more sensitive.

We compared results with three commercial folate radioassay kits [Bio-Rad, New England Nuclear (NEN), and RIA Products] with those by microbiological assay for more than 200 samples of human serum and whole blood. All but one kit (NEN) compared favorably with the microbiological assay for serum samples, although there were notable diagnostic discrepancies. Two kits (NEN and Bio-Rad) were tested...