Green micellar liquid chromatographic method for simultaneous determination of antihistaminic drugs tripelennamine hydrochloride and diphenhydramine in pharmaceutical gel

A new green micellar liquid chromatographic method has been developed and validated for the simultaneous determination of diphenhydramine (DPH) and tripelennamine hydrochloride (TRP) using a micellar mobile phase consisting of 1 mM Tween 20 in phosphate buffer pH 4:isopropanol (85:15, %v/v). The method was linear in the range of 4-150 and 5-120 μg/mL for TRP and DPH, respectively. The method was successfully applied for the simultaneous determination of DPH and TRP in a laboratory-prepared gel containing all possible excipients with mean percent recoveries ± standard deviation of 100.346 ± 1.265 and 100.754 ± 1.117 for TRP and DPH, respectively. The method was validated according to the International Conference on Harmonization guidelines. The method is confirmed to have excellent greenness.