Spectrophotometric determination of nimodipine, nitrendipine, lacidipine in tablets via derivatization with para-dimethylaminobenzaldehyde

Abstract

The proposed approach involves the interaction of NIM, NIT, and LAC directly with DABA reagent to produce coloured products with its further spectrophotometric analysis by the development of simple, available, and alternative spectrophotometric methods.

Material and methods: UV-visible double beam spectrophotometer Shimadzu UV-1800 (Japan) with included UV-Probe version 2.62 software was employed. Additional equipment included a precise analytical balance RAD WAG AS 200/C (Poland), an ultrasonic bath Elmasonic EASY 60H with a frequency of 40 kHz and a water bath VB-4 were used in the developed procedure. LAC, NIM and NIT (purity ≥98% (HPLC)) were supplied from Sigma-Aldrich Chemicals Co. (St. Louis, MO, USA). NIT 10 mg tablets, NIM 30 mg tablets were purchased from local drugstore. LAC 2 mg tablets were purchased from europharm.com.ua.

Methanol was produced by Honeywell and had a purity of 99.9%. HCl conc. (fuming,  by Sigma Aldrich was used. DABA utilized in the experiment was analytical grade.

Results and discussion: Simple, available and alternative visible spectrophotometric methods for the determination of nitrendipine (NIT), nimodipine (NIM), and lacidipine (LAC) in tablets through derivatization with the para-dimethylaminobenzaldehyde (DABA) have been developed. The optimal parameters for CCBs spectrophotometric analysis were as follows: detection wavelength - 577 nm for NIM, NIT and 616 nm for LAC, concentrated hydrochloric acid, 1.5 mL of 0.1% DABA solution, 15 min boiling at 100 °C. The concentration was linearly proportional to absorbance values in the range of 25 – 175 μg/mL (NIT), 25 – 200 μg/mL (NIM), 20 – 200 μg/mL (LAC). Estimation of LOD and LOQ parameters were obtained as 3.75 μg/mL and 11.38 μg/mL (NIT), 4.43 μg/mL and 13.43 μg/mL (NIM), 6.30μg/ml and 19.1μg/mL (LAC).

Conclusions. In this work, thorough scientific research was carried out with the presentation of the method of selection of the optimal reaction conditions and spectrophotometric methods for determining NIT, NIM, and LAC in tablets were developed. In addition, the three studied CCBs were quantified using easy-to-implement, simple, cost-effective spectrophotometric approaches. The proposed methods can be used as alternatives and arbitrage, which significantly expands the bank of analytical methods. Moreover, the described methods can be easily implemented for routine pharmaceutical analysis