Monoester formation by hydrolysis of dialkyl phthalate migrating from polyvinyl chloride products in human saliva

Abstract

The migration dialkyl phthalate was tested in volunteers who chewed polyvinyl chloride (PVC) toy products under controlled conditions. The PVC toy samples consisted of ball A containing 100 and 185 mg/g di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) respectively, and ball B, containing 256 mg/g diisononyl phthalate (DINP). The migration of dialky phthalate into simulated saliva was also tested in vitro by shaking toy samples. The migration rates of DBP, DEHP and DINP from balls A and B were 11.7, 44.4 and 78.0 μg/10 cm2/hr, respectively, in vivo, and 339, 315 and 535 μg/10 cm2/hr, respectively, in vitro. The presence of mono-n-butyl phthalate (MBP) and mono-2-ethylhexyl phthalate (MEHP) in saliva collected after chewing ball A was confirmed by GCMS-SIM. Human saliva which collected from volunteers incubated with DBP and DEHP at 37°C over 60 min, hydrolyzed these compounds to their monoesters.