DETERMINATION OF THE RETINOBENZOIC ACID-DERIVATIVE AM580 IN RAT PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A specific liquid chromatographic method for the determination of hydr o-5,5,8,8-tetramethyl-2-naphthalenyl)carbonyl] amino] benzoic acid (Am 580) in rat plasma is described. The procedure includes one-step isola tion of the compound and the internal standard (naphthol AS) from prot ein precipitated with acetonitrile, resolution on a reversed-phase col umn (Supelcosil LC18-DB, 5 mu m) with water-acetonitrile-methanol-n-bu tanol (45:40:14:1, v/v) containing 65 mM ammonium acetate as elution s ystem and UV absorbance detection at 280 nm. The assay was linear over a wide range (25-5000 ng ml(-1)) and the limit of quantitation was 25 ng ml(-1) using 0.2 ml of plasma. It was precise and reproducible eno ugh for pharmacokinetic studies. Application to a preliminary disposit ion study in the rat indicated that Am580 was characterized by a relat ively large apparent volume of distribution (1.1-1.5 l kg(-1)) and sma ll clearance (8.8-9.7 ml min(-1) kg(-1)). Its pharmacokinetic behaviou r was linear within the dose range considered (2 and 10 mg kg(-1), i.p .).