Determination of L-alanosine in plasma and urine by reversed-phase high-performance liquid chromatography of the Dns derivative.

L-Alanosine is an antitumour antibiotic that has recently been placed in clinical trial. We have developed a relatively rapid and specific assay for urinary and plasma alanosine, based on formation of the Dns derivative and separation of this from other Dns compounds by reversed-phase high-performance liquid chromatography. Dns-Alanosine is detected by its absorption at 254 nm, since alanosine is atypical in that it forms a Dns derivative with very low fluorescence. The lower limit of detection of alanosine in plasma is 0.1 microgram/ml. The assay has been used to measure the levels of alanosine in the plasma and urine of rabbits and of man.