TY - JOUR T1 - THE METABOLISM OF 1-HYDRAZINOPHTHALAZINE JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 7 LP - 13 VL - 143 IS - 1 AU - William M. McIsaac AU - Masayuki Kanda Y1 - 1964/01/01 UR - http://jpet.aspetjournals.org/content/143/1/7.abstract N2 - A study has been made of the metabolism of C14-1-hydrazinophthalazine in rats and rabbits. The activity of various tissues following administration of C14-1-hydrazinophthalazine has been estimated. Eighteen per cent of the dose was circulating in the blood 8 hours after intraperitoneal administration. Excretion of metabolites of 1-hydrazinophthalazine was rapid, 75% of the radioactivity appearing in the urine in 24 hours. The following metabolites were identified: 1-hydrazinophthalazine-O-glucuronide, N-acetyl-1-hydrazinophthalazine, unchanged 1-hydrazinophthalazine and its pyruvic hydrazone. Quantitative estimation of these metabolites by scanning radioactive chromatograms and by isotope dilution showed that 1-hydrazinophthalazine-O-glucuronide (40-50%), 1-hydrazinophthalazine (15%), N-acetyl-1-hydrazinophthalazine (25-30%), hydroxy - 1 - hydrazinophthalazine (<5%), and hydrazinophthalazine pyruvic acid hydrazone (<5%) accounted for all the activity in urine. 1-Hydrazinophthalazine pyruvic hydrazone and N-acetyl-1-hydrazinophthalazine were less toxic than 1-hydrazinophthalazine. 1-Hydrazinophthalazine was found to be unstable at alkaline pH. The Williams & Wilkins Company ER -