Nagaraju Rajana^1,2,*, B. Srikanth¹, D.V. Ramana¹, Kaviraj M. Yarbagi¹, P. Madhavan¹, J. Moses Babu³, K. Basavaiah² and Dharamasoth Rama Devi⁴

¹Technology Development Center, Custom Pharmaceutical Services, Dr. Reddy’s Laboratories Ltd., Miyapur, Hyderabad-500 049, India

²Department of Inorganic & Analytical Chemistry, Andhra University, Visakhapatnam-530 003, India

³Integrated Product Development Organization, Dr. Reddy’s Laboratories, Innovation Plaza, Bachupally, Hyderabad-500 072, India

⁴Andhra University College of Pharmaceutical Sciences (Andhra University), Visakhapatnam-530 003, India

*Corresponding author: E-mail: nagarajurajana@drreddys.com; nagarajrajana@gmail.com

The present analytical method was developed for single determination of three counter ions in pantoprazole sodium, losartan potassium and omeprazole magnesium drug substances by ion chromatography. The ion chromatography method was unique and suitable for three drugs such as pantoprazole sodium, losartan potassium and omeprazole magnesium with specification limits 5.7, 8.5 and 3.3 % of percentages of sodium, potassium and magnesium counter ions, respectively. The method was developed with Metrosep C₄ (150 × 4.0 mm, 5 μ) column and combination of 4.0 mM nitric acid, 0.1 % dipicolinic acid and 10 % acetonitrile with flow of 1 mL. The injection volume used for this analysis was 20 μL with conductivity detector. The validation was performed to single ion chromatography method for three counter ions such as sodium in pantoprazole sodium, potassium in losartan potassium and magnesium in omeprazole magnesium. The % RSD for the method precision and intermediate of sodium in the pantoprazole sodium was 1.6 % and 1.6 %, respectively. The correlation coefficient for the linearity parameter of the sodium in the pantoprazole sodium was 1.000. The accuracy of sodium in pantoprazole sodium was observed as 97, 101 and 103 % recovery at 50, 100 and 150 %, respectively. The % RSD for the method precision and intermediate of potassium in the losartan potassium was 2.0 % and 1.5 %, respectively. The correlation coefficient for the linearity of the potassium in the losartan potassium was 0.999. The accuracy of potassium in losartan potassium was observed as 97.2, 100.0 and 101.8 % recovery at 50, 100 and 150 %, respectively. The % RSD for the method precision and intermediate precision of magnesium in the omeprazole magnesium was 1.7 and 2.0 %, respectively. The correlation coefficient for the linearity of the magnesium in the omeprazole magnesium was 1.000. The accuracy of magnesium in omeprazole magnesium was observed as 113.1, 98.5 and 98.5 % recovery at 50, 100 and 150 %, respectively. The robustness study was performed for flow of mobile phase from the actual flow and acetonitrile concentration. All the robustness values were less than the 10 % of initial counter ion content. The developed and validated method can be used for the simultaneous determination of sodium, potassium and magnesium counter ions in pantoprazole sodium, losartan potassium and omeprazole magnesium, respectively.

Pantoprazole sodium, Losartan potassium, Omeprazole magnesium, Counter ions, Validation, Ion chromatography.