Use of a Specific and Sensitive Assay to Determine Pentamidine Pharmacokinetics in Patients with AIDS

The first-dose pharmacokinetics of pentamidine were studied in patients with AIDS. Pentamidine isethionate (4 mg/kg) was administered intramuscularly or intravenously to two groups of six patients each. Serial plasma and urine concentrations were measured by high-performance liquid chromatography, which is accurate and precise (sensitivity limits, 2.29 ng/ml in plasma and 229 ng/ml in urine). The mean peak concentrations in plasma after intramuscular and intravenous administration were 209 ng/ml and 612 ng/ml, respectively. Plasma concentrations, which declined biexponentially, were detectable throughout the 24-hr dosing interval and fell to