Determination of metoprolol tartrate by capillary isotachophoresis

Abstract

This paper describes two isotachophoretic methods of metoprolol tartrate (MT) determination in pure and dosage forms. The first method was used for direct analysis where the following electrolyte system was applied: 10 mmol dm⁻³ 3-morpholino-2-hydroxypropanesulfonic acid, 10 mmol dm⁻³ NaCl, 2 % hydroxyethylocelulose as leading (LE) and 10 mmol dm⁻³ glycyl-glycine as terminating (TE) electrolytes. The second method was used for indirect analysis of MT as tartrate ions. In this case, the leading electrolyte consisted of 10 mmol dm⁻³ HCl, β-alanine (BALA), pH 4-5, and the terminating one of 5 mmol dm⁻³ glutamic acid, 10 mmol dm⁻³ β-alanine. Calibration curves were calculated as follows: for system A: y = (0.52 ± 0.05)x − (0.9 ± 0.2) (LOD = 13.0 mg dm⁻³, LOQ = 31.7 mg dm⁻³); and for system B: y = (0.240 +- 0.001)x + (0.18 ± 0.06) (LOD = 1.8 mg dm⁻³, LOQ = 4.4 mg dm⁻³). The isotachophoretic method was compared with the pharmacopoeial one by statistical tests.