Methodological aspects of an agar plate technique for determination of biologically active 5-fluorouracil in blood, urine and bile.

A microbiological agar plate technique for estimation of 5-fluorouracil concentrations in blood, urine and bile from man, dog and pig was evaluated. Different bacterial test strains, media modifications and techniques for inoculation were studied. The strain Streptococcus faecalis ATCC 8043, recommended previously by Clarkson et al., was found to be the most suitable. The influence of prediffusion, dilution, antibiotics and chemotherapeutic agents and their antagonists, as well as the effect of storage of samples containing 5-fluorouracil were examined. A detailed methodological description is presented. The method seems to be sufficiently sensitive and practical for routine determination of cytotoxic compounds from 5-fluorouracil in serum, plasma and urine.