Simultaneous Estimation of Diphenhydramine Hydrochloride and Naproxen Sodium in Raw and Tablet Formulation by Reverse Phase - High-Performance Liquid Chromatographic Method

Aims: A simple, reproducible method was developed for the simultaneous determination of Diphenhydramine and Naproxen in tablet formulation using reverse phase HPLC method. Methodology: HPLC separation was carried over on Thermo hypersil – keystone C18 (250 x 4.6 mm, 0.5 m) isocratic mode column using a mobile phase comprising a 30:70 (% v/v) of methanol and 0.5 mM phosphate buffer. The detection was proceeded out by UV detector at 270 nm. The linearity range taken for Diphenhydramine and Naproxen were 15 – 35 mcg/ml and 100-500 mcg/ml respectively.

Results: The percentage recovery was found to be 99.74% and 101.11% for Diphenhydramine and Naproxen respectively. The amount of Diphenhydramine and Naproxen found in tablet was 25.006 mg and 219.07 mg respectively. The proposed RP-HPLC method shows a good separation of Diphenhydramine and Naproxen, the retention time was found to be 3.1 minutes for Diphenhydramine and 4.9 minutes for Naproxen.

Conclusion: The proposed method shows very less time consuming analysis. The proposed method of analysis shows good separation at less retention time and less cost. The developed method can be successfully applied for the determination of Diphenhydramine and Naproxen in bulk powder and combined tablet dosage form.