Novel eco-friendly spectrophotometric determination of lercanidipine hydrochloride in tablets using methyl red

Abstract

The aim of the work was to develop a simple, eco-friendly, quick, affordable and alternative spectrophotometric procedure that uses the azodye methyl red (MR) for the determination of lercanidipine in its dosage form considering the “green” chemistry principles. Materials and methods. Analytical equipment: Shimadzu UV-1800 double beam UV-visible spectrophotometer (Japan) with included UV-Probe 2.70 software, RAD WAG AS 200/C precise analytical balance (Poland), Elmasonic EASY 40H ultrasonic bath. Lercanidipine hydrochloride (purity 99 %) was purchased from Jiyan Chemicals (India). Lercanidipine tablets 10 mg and 20 mg were used in our experiments. Results and discussion. To determine the amount of lercanidipine in tablets, a spectrophotometric method has been developed. To select the best dye for the method development, we tested a variety of dyes, including MR, bromocresol purple, bromophenol blue, cresol red, bromocresol green and bromothymol blue. We selected MR as the reagent based on the experimental studies' outcomes, and the solvent was an acetonitrile and ethanol mixture with a ratio of 95 to 5. The optimal parameters were determined for the quantitation of lercanidipine in tablets utilizing MR with 5×10-5 mol/L of dye concentration, 0.5 ml of MR solution, at a temperature of 25 °C without heating; detection wavelength was 498 nm and reaction time of 5 min. By using the molar ratios (saturation) method and Job's (continuous variations) approach, the stoichiometric coefficients of reacting components involving lercanidipine and dye were established to be 1:1. The proposed spectrophotometric procedure was linear within the concentration ranging from 6.48 – 32.41 μg/mL. Using the least squares method, a regression equation was generated: y = 0.0208x – 0.0318. The correlation coefficient was higher than 0.999, indicating that the analytical procedures' linearity is acceptable; the limit of detection and limit of quantitation were 1.19 μg/mL and 3.62 μg/mL, respectively. The robustness, accuracy and precision of the study results fell within acceptable limits. The proposed method was successfully applied to determine the content of lercanidipine in its tablet dosage forms. The analysis of the method's "greenness" using AGREE and GAPI tools yielded excellent results. Conclusions. The method that has been developed can serve as an alternative approach for the routine control of lercanidipine content in its tablets