Simultaneous determination of lignocaine hydrochloride, chlorhexidine gluconate, and triamcinolone acetonide in suspension by reversed-phase HPLC

The validation of an isocratic high performance liquid chromatographic (HPLC) procedure for the simultaneous determination of lignocaine hydrochloride, chlorhexidine gluconate and triamcinolone acetonide in suspension is reported. Reverse phase chromatography was conducted using 250 x 4.6 mm I.D. 5 mu m C-18 column and monitored on a UV detector at 240nm. Two mobile phases were used: mobile phase A comprised a mixture of methanol/water/triethyl amine (58:42:0.4) and the pH adjusted to 3 with phosphoric acid for analysing active ingredients, and mobile phase B was a mixture of methanol/0.01 N ammonium acetate (70:30) for limit testing related substances. Linear response (r > 0.999) was observed over the range of 20-240% of its label claim. The intra-day precision (RSD) of label claim amongst five independent sample preparations, was not more than 0.64% for peak area, and there was no significant difference (P < 0.05) between intra- and inter-day studies. Intermediate precision, as determined from twenty sample preparations, generated by two analysts on different HPLC systems over 7 days, indicated that the assay possessed high degrees of ruggedness by ANOVA test. Recovery studies showed good results for all solutes (99.20% - 100.52%) and coefficients of variation ranging from 0.28% to 1.19%. The method showed that the excipients of the commercial suspension and potential degradation impurities caused no interferent effect in the determination of the active ingredients. Related substance limit test indicated that the amount of degradation impurities could be monitored which was important for evaluating the impact of manufacturing process or source changing on product quality. The stability studies at room temperature demonstrated that the drug is stable for at least 1 year. The method is simple, rapid, specific, and reliable, and can be successfully used for the quality control on commercial bulk product.