The sensitivity of the colorimetric determination of alkylating cytostatics with 4-(4'-nitrobenzyl)pyridine (NBP) has been increased by modifying procedures described in the literature. This increase in sensitivity was accomplished as follows: --Precipitation of protein with absolute ethanol at degree C; --reduction of the sample volume by evaporating the ethanol extract in a nitrogen flow; --control of the optimum pH value by means of a micro-glass electrode; --meticulously timed working under cooling in a dimmed room. The total alkylating activity and the part of endogenously activated cyclophosphamide were determined in four patients.
Alkylating Agents Antineoplastic Agents