Electrochemical sensors for direct determination of simvastatin in pharmaceutical formulations and biological fluids

• NAWAL A ALARFAJ ^[1] ; FATMA A ALY ^[1] ; MAHA EL-TOHAMY ^[1]
  1. [1] King Saud University

     King Saud University

     Arabia Saudí

     
• Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 57, Nº. 2, 2012, págs. 1140-1146
• Idioma: inglés
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• Resumen

  • The construction and performance characteristics of simvastatin (SIM) selective electrodes were developed. Three types of electrodes: plastic membrane I, coated wire II, and coated graphite rod III were constructed based on the incorporation of simvastatin with phosphotungstic (PTA) or phosphomolybdic (PMA) acids and mixed ion pair (PTA/PMA) for the three electrodes, respectively. The influence of membrane composition, kind of plasticizer, type of ion-pair, pH of the test solution, soaking time, and foreign ions on the electrodes was investigated. The electrodes showed a Nernstain response with a mean calibration graph slope of 56.24±0.43, 55.44±0.14 and 58.93±0.34 mV decade-1 at 25°C over simvastatin concentration range from 1.0 x 10-6-5.0 x 10-2, 9.0 x 10-6-5.0 x 10-3 and 9.0 x 10-7-1.0 x 10-2 mol L-1, with detection limit of 5.0 x 10-7, 3.9 x 10-6 and 3.2 x 10-7 mol L-1 for electrode I, II and III, respectively. The pH range for the proposed electrodes was 4-7. The influence of possible interfering species such as common inorganic cations, many sugars, amino acids and a pharmacologically related drug 'ezetimibe' was studied. Statistical student's t-test and F test showed insignificant systematic error between proposed and official methods.