GLC Determination of Aprindine in Human Plasma Using a Nitrogen-Phosphorus Flame-Ionization Detector

A procedure for the determination of aprindine in human plasma was developed. After the addition of N,N-diethyl-N′-(1,2,3,4-tetrahydro-2-naphthyl)-N′-phenyl-1,3-propanediamine as an internal standard, the plasma was buffered to pH 8.0, and the drug and the internal standard were extracted into ethyl acetate-hexane (9:1 v/v). The compounds then were extracted from the organic phase into 0.02 N HCI. The acidic solution was made basic with 0.2 M tribasic sodium phosphate, and aprindine and the internal standard were extracted into a small volume of hexane. The compounds were analyzed by GLC using a nitrogen-phosphorus flame-ionization detector. The drug concentration and instrument response were linear for 0.10–1.00 μg of aprindine/ml, the slope was 1.1416 (0.0141), the y intercept was 0.0096 ± 0.0082, and the correlation coefficient was 0.99960 ± 0.00002. The sensitivity of the method was 0.02 μg of aprindine/ml. The within-day coefficient of variation was 9.50, 3.10, 3.14, and 2.21% for 0.05, 0.20, 0.40, and 0.80 μg of aprindine/ml, respectively. The between-day coefficient of variation was 17.4, 3.40, 2.07, and 1.54% at the same concentrations. Total precision values of 19.9, 4.60, 4.26, and 2.69% were obtained. The overall relative error of the method was +1.33, +2.00, -0.07, and +0.25% at these concentrations.