NMR Quantitative Analysis of Quinidine in Mixtures of Quinidine and Hydroquinidine

Comparison of Two Spectrofluorometric Procedures for Quinidine Determination in Biological Fluids

“…The two dashed lines (---) parallel to the regression line (-) have a vertical distance from it that cs equal to the standard error of estimate.When quinidine was added to eight plasma samples to obtain 0.1-5-pg/ml concentrations, the mem, values of the percent found were 98.5 (SD = 4.1 and CZ6 = 3.4) and 100.9 (SD = 3.2 and CZ = 2.6) for the protein precipitation method and benzene extraction procedure with alkaline washing, respectively. These results demonstrate that there is a good recovery of quinidine and hydroquinidine(8) with no significant loss of the alkaloids resulting from the alkaline washings of the benzene extract.Theaddition of 0.1-150 pglml of quinidine to 14 urine samples led to a mean percent of 98.1 (SD = 2.5 and CZ = 1.5) when the benzene extract was washed with an alkaline solution. The reproducibility of the extraction procedures was also checked by five measurements on the patient urine sample used for TLC analysis.…”