Simultaneous determination of five 1,4-dihydropyridines in pharmaceutical formulations by high-performance liquid chromatography-amperometric detection.
A high-performance liquid chromatographic method with electrochemical detection was developed for the simultaneous determination of five 1,4-dihydropyridines: amlodipine, nitrendipine, felodipine, lacidipine and lercanidipine. These drugs are widely used in the treatment of hypertension, angina pectoris and the therapy of cerebrovascular spasms of various origins. The chromatographic separation was performed on a Supelcosil LC ABZ + Plus C18 column with a mobile phase consisting of acetonitrile-10 mM acetate buffer (72:28, v/v) at a flow rate of 1 ml/min. The temperature was set at 30 +/- 0.2 degrees C. The amperometric detector, equipped with a glassy carbon electrode was operated at +1100 mV versus Ag/AgCl in the direct current mode. Under these chromatographic conditions, the drugs eluted in less than 12 min. The method showed to be linear over the range 4.5-15 microg/ml with a within-day and day-to-day repeatabilities in terms of R.S.D. lower than 15%, an accuracy greater than 98% and detection limits varying from 90 ng/ml (amlodipine) to 1.55 microg/ml (nitrendipine). The method was successfully applied to commercially available pharmaceuticals with relative errors lower than 5%. The validity of the method was examined comparing the results obtained with those of HPLC with photometric detection.
Baranda
Ana B
AB
Departamento de Química Analítica, Facultad de Ciencias, Universidad del País Vasco/EHU, Apdo. 644, 48080 Bilbao, Spain.
Jiménez
Rosa M
RM
Alonso
Rosa M
RM
D002138:Calibration; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D004095:Dihydropyridines / Q000032:analysis*; D004563:Electrochemistry; D004566:Electrodes; D007202:Indicators and Reagents; D015203:Reproducibility of Results; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013607:Tablets
D004095:Dihydropyridines; D007202:Indicators and Reagents; D012996:Solutions; D013607:Tablets