Propofol emulsion was studied to determine the effects of filtration and of passage through an i.v. administration set on drug concentration. To study syringe filter effects, propofol emulsion samples (Diprivan Injection, 10 mg/mL) were discharged through either a 5-mm filtering needle or a standard needle. To determine the effects of the i.v. administration set on propofol delivery, a diluted dispersion containing approximately 2 mg/mL was prepared from propofol emulsion and 5% dextrose injection. This formulation was siphoned into a 6-foot length of administration set tubing, from which samples were withdrawn at 0, 30, 60, and 120 minutes. Another 2-mg/mL diluted dispersion of propofol and 5% dextrose injection was placed in a glass reservoir and delivered through a 6-foot i.v. set at a rate of 1.75 mL/min, which corresponds to a low dosage rate of 0.05 mg.kg-1.min-1. Samples of the effluent were collected at 0, 5, 10, 15, 30, 60, 90, and 120 minutes. Samples collected from all three tests were assayed by using high-performance liquid chromatography. The mean propofol concentrations in the filtered and unfiltered samples were 96.05% and 96.09% of label claim, respectively, after discharge through needles; the difference was not significant. In the static study of the i.v. tubing effects, a 31.54-34.74% loss of propofol occurred after 120 min. In the study of propofol flowing through the i.v. tubing, the concentration dropped slightly in the initial sample, which was taken after the propofol was placed in the tubing. The concentration remained essentially constant for the first hour and then declined, with an overall average loss of 7.70%.(ABSTRACT TRUNCATED AT 250 WORDS)