Pharmacokinetics, plasma protein binding and urinary excretion of N^ω‐nitro‐L‐arginine in rats

The in vivo disposition of N^ω‐nitro‐l‐arginine (l‐NOARG) has been examined in rats. Plasma concentrations of l‐NOARG following an intravenous dose of 10 mg kg⁻¹ were determined by high‐performance liquid chromatography. Plasma l‐NOARG concentrations declined biexponentially, with average half‐lives of 11 min and 20 h. l‐NOARG clearance did not appear to exhibit concentration‐dependency below a plasma concentration of 4.56 × 10⁻⁴ m (100 mg 1⁻¹). Ultrafiltration studies revealed insignificant binding of l‐NOARG to rat plasma proteins. Urinary excretion of unchanged l‐NOARG was minimal. These pharmacokinetic information may be useful in the design of in vivo experiments involving l‐NOARG, as well as in the interpretation of the pharmacodynamics of this important nitric oxide synthase inhibitor. 1994 British Pharmacological Society