The blood level of sulfamonomethoxine (SMM) in the dog and its kinetics were studied. The free form and the acetylated form of SMM were successfully isolated by thin layer chromatography. They were further determined by the method described by Bratton and Marshall with a slight modification. Since various undetermined substances were contained in the urine of dogs positive for Bratton and Marshall's reaction, they were also isolated by thin layer chromatography prior to analysis. When injected

more »

... ntravenously, SMM disappeared from the blood circulation at the rate of 3.6% an hour, and excreted in urine at the rate of 2.5% an hour. The total amount of theoretical excretion of SMM in urine was 65.8%. The theoretical space of distribution of SMM in the body was 448.5 m//kg. Calculation revealed that 53.8mg/kg of SMM was required to keep a blood level of 5 mg/d/ 24 hours after injection. In dogs, the deacetylation of acetyl-SMM was