Sorption of Drugs by Plastic Infusion Bags

Abstract

Abstract The sorption of warfarin sodium, various benzodiazepines and a number of other drugs from aqueous solutions by poly vinyl chloride infusion bags was investigated. The sorption kinetics for warfarin and diazepam could be accounted for by a diffusional model in which the loss of drug is determined primarily by the diffusivity of the compound in the plastic matrix. The rate and extent of sorption of warfarin showed a dependence on pH which could be interpreted in terms of ionization of the drug, i.e. only the unionized form was sorbed. A rank order relationship was shown between the initial rate of uptake by the plastic bag and the hexane-water partition coefficients of the compounds. It is suggested that the latter parameter may be useful for the prediction of interactions between a drug substance and polyvinyl chloride infusion bags. Sorption of the compounds by infusion bags made from polypropylene was insignificant except for the highly lipophilic medazepam and accordingly, such bags may be more safe to use than polyvinyl chloride bags in respect to drug sorption.