A microbiological assay for estimating concentrations of camptothecin lactone in mouse tissues.

The marked sensitivity of the yeast Hansenula wingei NRRL Y-2340 strain 5 to a new antineoplastic alkaloid served as the basis for a logarithmic-ratio microbiological assay which has been developed for the estimation of concentrations of camptothecin lactone (or cytotoxic equivalents) in tissues of mice. The utility of this assay has been demonstrated by presenting data which show the concentrations of camptothecin lactone (or cytotoxic equivalents) detected in various tissues of mice at intervals following intraperitoneal injection of a 1 or 0.5 ld(10) dose of this drug.