Drug Interactions with Poly(vinyl chloride) Plasticized with Epoxidized Soybean Oil

Plastic infusion tubing is commonly made of plasticized poly(vinyl chloride) (PVC). During infusion, drugs may sorb into the tube influencing the drug amount delivered to the patient and may result in a lower efficiency of the treatment that may compromise the success of the therapy. In this study, the sorption of diazepam from aqueous solutions by PVC-plasticized films was investigated. Epoxidized soybean oil (ESBO)-plasticized films were compared to di-2-ethylhexyl-phthalate (DEHP)- and DEHP/ESBO-plasticized films. ESBO is mainly used as a thermal stabilizer in tubing, but it can be an effective primary and less toxic plasticizer as proven by its use in food packaging. The sorption behavior was different for pure ESBO compared to DEHP and DEHP-based mixtures. This might be interpreted in terms of interaction between the PVC and the plasticizer. The plasticizer's ability to phase separately above a specific ratio may be a significant parameter.