HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF INTRATHECALLY ADMINISTERED [D-ALA(2)-D-LEU(5)]-ENKEPHALIN CONCENTRATIONS IN CANINECEREBROSPINAL-FLUID

A rapid and useful method for high-performance liquid chromatographic analysis of exogenous [D-Ala(2)-D-Leu(5)]-enkephalin (DADLE) in cerebr ospinal fluid (CSF) is described. CSF (0.5 mi) samples were filtered u sing a 0.22-mu m Co-Star filter. Chromatography was performed on a mu Bondapak C-18 column using a mobile phase of A, 0.05 M sodium phosphat e (monobasic, pH 6.0) and B, 60% acetonitrile in 0.05 M sodium phospha te (pH 6.0) with a flow-rate of 1 ml/min. Absorbance at 210 nm was mea sured. The procedure produced a linear curve for the concentration ran ge 1-10 mu g/ml. The development of the assay produced rapid, repeatab le and accurate results for CSF analysis of DADLE at concentrations ac hieved with therapeutic administration of the peptide. This method cou ld also be used in the future for analysis of compounds like DADLE.