The salivary secretion and clearance in the horse of chloral hydrate and its metabolites

The salivary secretion of chloral hydrate and its metabolites in the horse have been studied. The concentration of chloral hydrate and trichlorethanol in saliva approximated to that in the plasma, but saliva levels of trichloracetic acid were much lower than plasma levels. Chloral hydrate and trichlorethanol were quickly absorbed after oral administration. About 60 per cent of the dose of chloral hydrate was excreted in the urine as the glucuronide of trichlorethanol ; traces of free trichlorethanol and trichloracetie acid were also detected. After chloral hydrate administration the main plasma constituents were trichlorethanol, trichloracetic acid, and chloral hydrate. Trichloracetic acid persisted longest in the plasma. Chloral hydrate could only be detected in the plasma for four or five hours after its administration whereas the other two metabolites persisted for much longer. Methods for the determination of trichlorethanol and chloral hydrate by gas-liquid chromatography using electron capture have been described. Trichloracetic acid was measured using the Fujiwara reaction. 6