Sorption of four drugs to polyvinyl chloride and polybutadiene intravenous administration sets.

Sorption of nitroglycerin, isosorbide dinitrate, diazepam, and clomethiazole edisylate (chlormethiazole) to polyvinyl chloride (PVC) i.v. administration sets with and without cellulose propionate burettes and to polybutadiene (PBD) sets with and without methacrylate butadiene styrene (MBS) burettes was studied. All drugs (except chlormethiazole) were diluted with 0.9% sodium chloride injection (NS) in glass bottles or in the burette chambers. Initial samples of each solution were obtained from the bottle or from the burette, and effluent samples were collected at various times up to 240 minutes from the sets without burettes and up to 90 minutes from the sets with burettes. For nitroglycerin, flow rates of 0.5 and 1.0 mL/min were used without the burette. The effect of priming the tubing before adding drug to the burette was studied for diazepam. Triplicate samples were analyzed for nitroglycerin and isosorbide dinitrate by high-performance liquid chromatography and for diazepam and chlormethiazole by ultraviolet spectrophotometry. Up to 50% potency of chlormethiazole and nitroglycerin, 15-25% of isosorbide dinitrate, and 13-20% of diazepam was lost to PVC sets without burettes, and an additional 10-15% loss of each drug resulted when PVC sets with burettes were used. Less sorption of nitroglycerin to the PVC sets occurred at the higher flow rate, but flow rate through the PBD sets did not affect sorption. Priming the tubing before adding diazepam to the burette did not affect final drug delivery. No loss to PBD sets was observed for nitroglycerin, isosorbide dinitrate, and diazepam; loss of chlormethiazole to PBD was 7-13%. Drug potency in effluent from PBD sets was not affected by presence or absence of a burette.(ABSTRACT TRUNCATED AT 250 WORDS)