Simultaneous determination of strontium ranelate and aspartame in pharmaceutical formulation for the treatment of postmenopausal osteoporosis by capillary zone electrophoresis

Abstract

A simple, accurate, precise, rapid and sensitive capillary zone electrophoresis (CZE) method was developed, optimized and validated for the simultaneous determination of strontium ranelate (antiosteoporetic drug) and aspartame (sweetener excipient) in pharmaceutical formulation for the treatment of postmenopausal osteoporosis. The final optimized conditions obtained were: borate buffer 50mmolL−1 at pH9.4 (BGE), applied potential of 30kV, temperature set to 35°C and hydrodynamic injection time of 10s at a pressure of 50mbar. The separation was carried out into a fused-silica capillary column (55cm total length×75μm ID) and took less than 8min. A diode array detector was used for the detection of the anion ranelate and aspartame at 235 and 198nm, respectively. For both analytes, the method showed linear range from 1 to 40μgmL−1, with satisfactory detectability (limits of detection of 0.3 and 0.2μgmL−1 for aspartame and ranelate, respectively). In addition, acceptable accuracy, good repeatability and intermediate precision (RSD<2.6%) were obtained. The feasibility of the method was verified with recovery tests of analytes in the pharmaceutical sample. Recoveries varied from 85±5% to 111±2%, indicating the usefulness and effectiveness of the proposed method.