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6196 
Journal Article 
Hydrolysis of vinyl acetate in human blood 
Fedtke, N; Wiegand, HJ 
1990 
Yes 
Archives of Toxicology
ISSN: 0340-5761
EISSN: 1432-0738 
NIOSH/00197285 
64 
5 
428-429 
English 
An investigation was conducted to clarify in which blood compartment the vinyl-acetate (108054) (VAc) hydrolysis, if any, takes place in human blood. The elimination of VAc from a closed system containing 1 milliliter (ml) of blood, 0.5ml of plasma, or 0.5ml red blood cells (RBC) diluted in 0.1 molar sodium-phosphate buffer, pH 7.4, was measured at 37 degrees-C by head space analysis. The initial VAc concentration in the solution was 200 micromolar in all experiments. The VAc half life in blood, plasma and RBC was calculated. VAc was eliminated with a half life of 4.1 minutes in human blood, whereas in rat blood the half life was less than 1 minute. Only minor VAc metabolic activity was noted in human plasma, resulting in the elimination of VAc with a half life of 62 minutes. VAc was hydrolyzed in rat plasma with a half life of 1.2 minutes. Preincubation of rat plasma with phosphoric-acid-bis-4-nitrophenyl-ester increased the half life to 191 minutes, suggesting the reaction was catalyzed by carboxylesterases. A rather high capacity for VAc elimination was detected in RBC. Upon addition of VAc to the incubation mixtures, an additional peak, identified as acetaldehyde, appeared on the chromatograms, increasing with the incubation time. The authors conclude that these results clearly indicate that hydrolysis of VAc is the main detoxification pathway in human and rat blood. The high capacity for VAc hydrolysis in the liver suggests that epoxidation of the double bond or the reaction of VAc with nucleophiles via Michael addition are not of major importance for the human exposure situation. 
vinyl acetate; metabolism; Toxicology Abstracts; hydrolysis; X 24153:Metabolism