Comparison of diisononyl phthalate migration from polyvinyl chloride products into human saliva in vivo and into saliva simulant in vitro

Abstract

Human volunteers chewed polyvinyl chloride (PVC) products under controlled conditions for 60 min (four consecutive periods of 15 min), and then the amount of diisononyl phthalate (DINP) migration into the saliva was determined by HPLC. The PVC products consisted of a molded plate containing added DINP (500 mg/g) and five types of commercial toy containing 160-583 mg/g DINP (mean value 372 mg/g). The DINP migration rates ranged from 3.8 to 32.6 μg/cm2/hr (mean value 16.4 μg/cm2/hr). The DINP contents in the toy products did not correlate with the amount of in vivo migration. The DINP migration rates during the last 15-min period (45-60 min) decreased by 38-75% compared with the first session (0-15 min). In addition, in vitro DINP migration rates from the PVC products into saliva simulant during 15 min of rotary shaking were about 3.6-4.1-fold higher than the rates in vivo over 60 min, and remained essentially fixed for each sample.