Determination of FCE 26644, a new polysulphonated derivative of distamycin A, in monkey plasma by reversed-phase ion-pair high-performance liquid chromatography with ultraviolet detection.

A sensitive and selective ion-pair high-performance liquid chromatographic method for the determination of 7,7'-carbonylbis[imino-N-methyl-4, 2-pyrrolecarbonylimino(N-methyl-4,2-pyrrole)carbonylimino]¿- bis(1,3-naphthalenedisulphonic acid), tetrasodium salt in monkey plasma has been developed. The compound and internal standard (bromphenol blue) were extracted from plasma samples were methylene chloride (twice) after deproteination with acetonitrile and addition of the ion-pairing agent (tetrabutylammonium hydroxide). The combined organic phases were dried, the residue dissolved in the mobile phase and then analysed by reversed-phase ion-pair liquid chromatography under isocratic conditions. The HPLC analysis time was about 20 min. Quantitation was achieved by UV detection at 323 nm. The linearity, precision and accuracy of the method were evaluated. The limit of quantitation was 0.3 microgram/ml plasma. No interference from blank monkey, mouse, rat, dog and human plasma was observed. The suitability of the method for in vivo samples was checked by analysis of plasma samples drawn from three male cynomolgus monkeys that had received a 20 mg/kg single i.v. dose of the test compound.