Simple high-performance liquid chromatographic method for the determination of PGT/1A, a new immunostimulating drug, in biological fluids.

This paper describes a simple high-performance liquid chromatographic method for the determination of PGT/1A (3-L-pyroglutamyl-L-thiazolidine-4-carboxylic acid), a new immunostimulating drug, in plasma and urine. The column was packed with LiChrospher-NH2 (5 microns), the mobile phase was 0.02 M monobasic potassium phosphate (pH 3.2 with concentrated phosphoric acid)-acetonitrile (25:75, v/v), the flow-rate was 1.2 ml/min, the detection wavelength was 210 nm and the apparatus was a Varian Model 5000. Plasma (1 ml) was added to 1.2 ml of acetonitrile and the supernatant injected; the urine was diluted 1:5. The retention time of PGT/1A was 9.4 min in plasma and 9.9 min in urine. The method was validated for recovery, accuracy and reproducibility. The results after intravenous injection in twelve volunteers are also given.