Determination of the spermicide nonoxynol-9 in vaginal lavage by high-performance liquid chromatography

A sensitive normal-phase high-performance liquid chromatographic method using a bonded-phase aminosilica column has been developed for the measurement of the spermicide nonoxynol-9 in vaginal lavage fluid. The mean multiple correlation coefficient (r²) for nonoxynol-9 was 0.999 over the calibration range 3.125-50 μg/ml for the standards. Quality control samples measured at two different concentration levels gave intra-day precision values (coefficient of variation, C.V.) in the range of 0.61 to 1.63% and the intra-day accuracy values (mean relative error, M.R.E.) in the range of 0.13-0.62%. Inter-day precision and accuracy values from five different calibration standard concentration values ranged from 2.25 to 5.09% C.V. and 4.02 to 7.56% M.R.E. Nonoxynol-9 samples examined for peak area stability at room temperature over a 24-h time period had a M.R.E. of 14.9%. Quality control samples stored at 70°C, and tested after one month by comparison to baseline samples, had a M.R.E. of -10% and -7.53% for the low and high quality control samples, respectively. The method is sensitive and simple, with short runtimes, to enable the processing of numerous samples from a clinical trial.