2-Chloroacetaldehyde, a metabolite of cyclophosphamide in the rat.

Following simultaneous i.v. administration of a mixture of [4-14C]cyclophosphamide (14C-CP) and [side-chain 3H]CP to rats, a metabolite containing predominantly 3H radioactivity was excreted in the urine. The 3H-labelled urinary metabolite was identified as 2-chloroacetaldehyde. Chloro[3H]acetaldehyde accounted for approx. 3.8% of urinary 3H radioactivity. The importance of chloroacetaldehyde as a toxic metabolite of CP is discussed, particularly in relation to haemorrhagic bladder disease.