capillary zone electrophoresis | Acta Medica Marisiensis

Letrozole Determination by Capillary Zone Electrophoresis and UV Spectrophotometry Methods

Aura Rusu¹, Maria-Alexandra Sbanca², Nicoleta Todoran³, Camil-Eugen Vari⁴

1 Department of Pharmaceutical Chemistry, University of Medicine and Pharmacy of Tîrgu Mureş
2 University of Medicine and Pharmacy of Tîrgu Mureş
3 Department of Pharmaceutical Technology, University of Medicine and Pharmacy of Tîrgu Mureş
4 Department of Pharmacology and Clinical Pharmacy, University of Medicine and Pharmacy of Tîrgu Mureş

DOI: 10.1515/amma-2017-0022

Objective: Letrozole is a highly potent oral nonsteroidal aromatase inhibitor triazole derivative. The aim of this study was to quantify letrozole from bulk, pharmaceutical formulation, and spiked urine samples by developing a simple, rapid and cost effective capillary electrophoresis method. Methods: A capillary zone electrophoresis method was optimized and validated. Additionally, an UV spectrophotometry method was used for comparing results. Results:The capillary zone electrophoresis method using a 90 mM sodium tetraborate background electrolyte proved to be an efficient method for determination of letrozole in a very short time, less than 2 minutes, using 20 kV voltage, 50 mbar/2 seconds pressure and 50°C temperature as optimum parameters. Additionally, the UV spectrophotometry method proved to be simple and efficient to quantify letrozole from bulk material and pharmaceutical formulation with linearity of response between 5 to 20 µg·mL-1 concentrations. For both methods, validation parameters, including linearity, detection and quantification limits were determined. Also we proved that our electrophoretic method has potential in analyzing letrozole from biological samples, obtaining encouraging results on estimation of letrozole from spiked urine samples without any special treatment. Conclusions: To quantify letrozole from bulk material, pharmaceutical preparations, and spiked urine samples the capillary zone electrophoresis method using a tetraborate sodium background electrolyte has proven to be simple and appropriate. Also a simple UV spectrophotometric method has been developed and validated for the same purposes.

Introduction: Antibacterial quinolones class comprises a series of synthetic antibacterial agents, following the model of nalidixic acid. Because of their common 6-fluorosubtituent on the quinolone ring, fluroquinolones are the most potent analogues with extended spectrum of activity and great pharmacokinetic properties. The applicability of capillary zone electrophoresis for the separation of fluoroquinolones in acidic background electrolyte has been studied, our aim being the development of a capillary zone electrophoresis method for the simultaneous separation of six fluoroquinolones and also to optimize the analytical conditions. The six studied fluoroquinolones were ciprofloxacin, enoxacin, enrofloxacin, moxifloxacin, ofloxacin and sarafloxacin.
Material and methods: Preliminary, we studied the electrophoretic behavior of six fluoroquinolones in an acidic pH, which highlighted the possibility of developing a separation method in this area of pH. Electrophoretic parameters influencing separation performance
were studied and optimized.
Results: A fast and reliable method has been developed, using a background electrolyte containing 100 mM phosphoric acid and the following conditions: applied voltage: + 25 kV, temperature: 20°C, injection pressure 30 mbar – 5 sec, UV detection at 280 nm, capillary: 60 cm (52 cm effective length) x 50 μm, analyte concentration: 167 μg/ml. The separation of the studied fluoroquinolones was achieved in less than 8 minutes.
Conclusions: Capillary zone electrophoresis using an acidic background electrolyte proved to be an efficient tool in the separation of fluoroquinolones from different generations. Also the proposed methods are particular environment-friendly replacement and improvement of a common high performance liquid chromatography determination with rapid analysis time without using any organic solvents.