Development and validation of a simple, fast, isocratic stability indicating RP-HPLC-UV method for the determination of chlorhexidine and its impurity para-chloroaniline in bulk and finished product

A simple, isocraticRP HPLC-UV method was developed for the simultaneous determination of chlorhexidine (CHD) and p-Chloroaniline (pCA) inchlorhexidine mouth rinses. An excellent separation obtainedbyC18 column (200mm × 4.6 mm, 3μm). Mobile phasewas acetate buffer:methanol in a 45:55 ratio,flowrate was 1.0 ml/min. Both ingredient and an impuritywere detected at 254 nm,injection volume was 20μl and the analysis temperature was room temperature.Resolution4.7,retention times was3.1min and 5.7 min for pCAand CHD respectively. The proposed method was testedforsystem suitability, linearity, range, precision, accuracy, specificity, robustness, detection and quantification limits. The linearity range was40-160μg/ml forCHD and0.3-1.2 μg/ml forpCA.The correlation coefficient of the regression line was 1.000 for both components. Method robustness was tested under nine different conditions using sampleswith a known content. For CHD, the mean of the nine assays was 99.95% andthe RSD was 0.16%. ForpCA, the mean of the nine assays was 99.98% and the RSD was 0.24%. The results show that this is a simple method that can be applied to the analysis of Chlorhexidineproductswith satisfactory degrees of accuracy and precision. Due to the selected optimized conditions, this method can be used with the minimum requirements of an isocratic HPLC system.