Determination of the anticancer drug, 15-deoxyspergualin, in plasma ultrafiltrate by liquid chromatography and precolumn derivatization with naphthalene-2,3-dicarboxaldehyde/cyanide.

An alternative analytical method for the determination of 15-deoxyspergualin in plasma is described. The drug was initially separated from the plasma matrix by ultrafiltration and a precolumn derivatization step was performed with naphthalene-2,3-dicarboxaldehyde in the presence of sodium cyanide to yield the fluorescent N-substituted 1-cyanobenz[f]isoindole (CBI) derivative. The CBI derivative was separated and quantitated by reversed-phase chromatography using an ODS Hypersil column and mobile phase of KH2PO4 (0.1 M)-H3PO4-acetonitrile (48:0.8:52, v/v/v) containing dodecyl sodium sulphate (18 mM). The excitation and emission wavelengths for the fluorescence detector were 420 and 490 nm, respectively. The peak height was linearly related to drug concentration over the range from 5 ng ml-1 (10 nM) to 10 micrograms ml-1 (20 microM) in phosphate buffer (0.1 M, pH 7.0), spiked plasma ultrafiltrate and ultrafiltrate obtained from spiked plasma. Measurements could be made with a relative standard deviation of 4.5% or less in phosphate buffer (0.1 M, pH 7.0), 6.1% or less in spiked plasma ultrafiltrate and 12% or less in ultrafiltrate obtained from spiked plasma.