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.