Determination of l-iminoethyl-l-lysine in serum by liquid chromatography

A selective and sensitive method is presented for the determination of l-iminoethyl-l-lysine (l-NIL) in rat serum. l-NIL is a selective inhibitor of the inducible nitric oxide synthase. The analytical technique is based upon a two-buffer reversed-phase HPLC system with fluorescence detection of pre-column derivatized amino acid analogue with o-phtaldialdehyde. The retention time of l-NIL was 19.4 min. The limit of quantification was 0.5 mg/l. After validation, the method was used to study the pharmacokinetic profile of l-NIL in rats after intravenous as well as oral administration of a single dose.