Performance evaluation of a novel potentiometric membrane sensor for determination of atorvastatin in pharmaceutical preparations

Abstract

A novel potentiometric ion-selective PVC membrane sensor for analysis of atorvastatin (AT) in pharmaceutical preparations based on atorvastatin-(tetraphenyl borate), (AT-(TPB)2) as sensing element, tetraphenyl borate as additive and tris-2-ethyl-hexyl phosphate (TOP) as plasticizer solvent was prepared. The electrode shows a good Nernestian response over the concentration range of 0.09-5586 μg mL(-1)of AT with slope of 30.1±0.1 mV/decade and limit of detection0.056μg mL(-1).The response time of sensor is fats (less than 10 sec) and could be used for about one month in the pH range of 4.5-8.0. The electrode exhibit good selectivity for the AT in the presence of large amount of co-drugs and inorganic cations. The method is precise and accurate with mean relative standard deviation of <2%.Atorvastatin is determined successfully in several tablets by the proposed membrane.

Keywords: Analysis of pharmaceutical preparation; Atorvastatin; PVC membrane; Potentiometric sensor.

Figure 1

Suggested structure of atorvastatin-tetraphenylborate (AT-(TPB)₂) ionpair

Figure 2

Electrode response for AT prepared with AT-(TPB)₂ ionpair as ionophore, the membrane contain of PVC:NaTPB:ionopher: TOP with 35:1.0:1.5:65%, respectively, the pH=4.0

Figure 3

Effect of pH of the test solution on the electrode potential reading, (●) 2234, (¡) 1.4and (▲) 0.14 μg mL^-1AT solutions, the composition of membrane was like to the membrane NO.9

Figure 4

Variation of ˚E_elec with temperature

Figure 5

Dynamic response of the PVC membrane electrode based on AT-(TPB)₂ for step change in activities of AT

Figure 6

Calibration curve of AT (μg mL^-1) obtained with proposed electrode at optimum membrane composition and measurement conditions