Determination of cetylpyridinium chloride and tetracaine hydrochloride in buccal tablets by RP-HPLC

The HPLC method for simultaneous determination of cetylpyridinium chloride (CPC), tetracaine hydrochloride (TTC) in Xipiluan buccal tablets was developed and validated. The HPLC method was performed on a CN column (150 x 4.6 mm i.d., 5 microm particle size); the mobile phase was methanol-tetramethylammonium hydroxide (20 mM)-potassium dihydrogen phosphate (3 mM) (90:10:3, v/v/v) (pH* 5.0), pumped at a flow rate 1.5 ml min(-1). The UV detector was set at 230 nm. The retention time for CPC and TTC was 3.52 and 3.10 min, respectively. Calibration curves were linear (r=0.9999, n=6) in the range of 5-2000 microg ml(-1) for CPC and 1-500 microg ml(-1) for TTC. Limit of detection and quantitation for CPC was 0.033 and 0.11 microg ml(-1), for TTC were 0.0056 and 0.019 microg ml(-1). The R.S.D. of repeatability and intermediate precision for CPC and TTC were less than 2.0%.