SPECTROFLUOROMETRIC DETERMINATION OF 2-CHLORO-2'-DEOXYADENOSINE (CLADRIBINE) IN HUMAN PLASMA BY PHOTOCHEMICAL-REACTION AND CHLOROACETALDEHYDE DERIVATIZATION

A quantitative fluorescence assay for 2-chloro-2'-deoxyadenosine (clad ribine, leustatin, 2-CdA) in human plasma is described. The drug was i solated from plasma by ethyl acetate extraction and derivatized by a t wo-step procedure in which 2'-deoxyisoguanosine (2'-diG) was first pre pared by UV irradiation of 2-CdA and was then treated with chloroaceta ldehyde to form the fluorescent derivative, 1,N-6-etheno-2'-deoxyisogu anosine. Fluorescence intensity of the solutions was measured using an excitation wavelength of 275 nm and emission of 397 nm. The analytica l measuring range of the method extends from about 1 mu g/l to at leas t 100 mu g/l.