A validated liquid chromatographic method for simultaneous quantification of Lidocaine hydrochloride and Diltiazem hydrochloride

This study examined treatment of anal fissure disease using newer combination of Lidocaine hydrochloride (HCl; LID) and Diltiazem HCl (DIL). Although both are old drugs, the combination is new for treatment. A simple and validated reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for simultaneous quantification of LID and DIL. RP-HPLC method comprised of Inertsil® C8-3 (150 × 4.6 mm, 5 µm) column as stationary phase along with mobile phase of 1 M potassium phosphate buffer:acetonitrile (63: 37 v/v), pH 7.0 adjusted with 10% ortho phosphoric acid. A detection wavelength of 220 nm was selected as optimized. The method was found linear 20–500 µg/ml for LID and DIL with 0.9961 and 0.9984 regression coefficient, respectively. The standard spiking method showed method accuracy with mean percentage recovery of 99.10–100.65% and 98.92–100.38% for LID and DIL, respectively. In conclusion, the method was found to be linear, precise, accurate, robust, rugged, selective, and specific for quantification of LID and DIL in bulk and gel dosage form and successfully can be applied for qualitative and quantitative determination of both drugs in bulk and marketed tablet formulation.