High-pressure liquid chromatography separation of phenobarbitone, thiourea, and thioacetamide of toxicological interest.

It was possible, by reverse-phase high-pressure liquid chromatography (HPLC) to separate thiourea, thioacetamide, and phenobarbitone with retention times of 1.4, 1.7, and 4.7 min, respectively. Thiourea and thioacetamide are known carcinogens. Substances such as phenobarbitone, thiourea, and thioacetamide, which may be encountered in our environment, can now be identified by this technique. It is also recommended that this HPLC technique should be used routinely in the screening of the purity of substances which are being subjected to toxicity, carcinogenicity, mutagenicity, and teratogenicity evaluation. A mixture of impurities in the sodium phenobarbitone was removed in the synthesis of the 5-ethyl-5-phenyl-barbituric acid (phenobarbitone). These substances which were not thiourea or thioacetamide could have been responsible for the positive result in the in vitro degranulation test for carcinogens with sodium phenobarbitone.