Development of the simultaneous analysis of choline salicylate, lidocaine hydrochloride and preservatives in a new dental gel by HPLC method

4 Department of Analytical and Toxicological Chemistry, Lithuanian University of Health Sciences, 13 Sukilėliai Avenue, 50161 Kaunas, Lithuania A new high-performance liquid chromatography (HPLC) method for the simultaneous quantitative determination of active pharmaceutical substances and preservatives in a new dental medication has been developed. The optimization of HPLC method parameters was done through studies of a mobile phase composition and a detection wavelength. Our developing method uses an ACE C18 column (250 × 4.6 mm, 5 μm) and a gradient mode for separation with the acetonitrile and phosphate buffer solution (adjusted to pH 3.0) as mobile phases. The flow rate is 1 ml/ min, and the detection was set at 260 nm (DAD). The method was evaluated according to the ICH guidelines and the State Pharmacopoeia of Ukraine in terms of specificity, accuracy, linearity and precision (repeatability and intermediate precision). The limit of detection and the limit of quantification were also calculated. The developed method was put in place for the analysis of a combined dental gel to a quantitative determination of the APIs (choline salicylate, lidocaine hydrochloride) and preservatives (methylparaben, propylparaben).