The absorption, distribution, excretion, and biotransformation of the carcinostatic 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea in animals.

The physiological disposition of l-(2-chloroethyl)-3cyclohexyl-1-nitrosourea, a highly active agent against intraperitoneal and intracranial mouse leukemia L1210, was studied in mice, rats, dogs, and monkeys with the 14C label in each of 3 positions of the molecule, the ethylene, carbonyl, and cyclohexyl moieties. l-(2-Chloroethyl)-3-cyclohexyl-l-nitrosourea is lipid soluble and, after parenteral dosage, rapidly degraded in mouse and dog plasma with 2 exponential phases. The half-life of the initial phase is about 5 min, while the 2nd phase ex tends over 1 hr. During the 6 hr after i.v. injection of ethylene-labeled 1-(2-chloroethyl)-3-cyclohexyl-1 -nitrosourea in dogs, radioactivity in the cerebrospinal fluid exceeded that of plasma 3-fold. With the label in the cy clohexyl moiety, plasma radioactivity was about 50% of cerebrospinal fluid UC levels. The drug following biotrans