Valsartan
Darwish, H. W., S. A. Hassan, M. Y. Salem, and B. A. El-Zeany,
"Different approaches in Partial Least Squares and Artificial Neural Network models applied for the analysis of a ternary mixture of Amlodipine, Valsartan and Hydrochlorothiazide",
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 122, pp. 744–750, 2014.
AbstractDifferent chemometric models were applied for the quantitative analysis of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in ternary mixture, namely, Partial Least Squares (PLS) as traditional chemometric model and Artificial Neural Networks (ANN) as advanced model. PLS and ANN were applied with and without variable selection procedure (Genetic Algorithm GA) and data compression procedure (Principal Component Analysis PCA). The chemometric methods applied are PLS-1, GA-PLS, ANN, GA-ANN and PCA-ANN. The methods were used for the quantitative analysis of the drugs in raw materials and pharmaceutical dosage form via handling the UV spectral data. A 3-factor 5-level experimental design was established resulting in 25 mixtures containing different ratios of the drugs. Fifteen mixtures were used as a calibration set and the other ten mixtures were used as validation set to validate the prediction ability of the suggested methods. The validity of the proposed methods was assessed using the standard addition technique.
Darwish, H. W., S. A. Hassan, M. Y. Salem, and B. A. El-Zeany,
"Rapid and sensitive TLC and HPLC with on-line wavelength switching methods for simultaneous quantitation of amlodipine, valsartan and hydrochlorothiazide in pharmaceutical dosage forms",
International Journal of Pharma and Bio Sciences, vol. 4, issue 1, pp. 345 - 356, 2013.
AbstractTwo RP-HPLC and TLC methods were developed and validated according to the
ICH guidelines for the simultaneous determination of Amlodipine, Valsartan and
Hydrochlorothiazide in tablet dosage form. The two methods are simple, rapid and
selective. Complete HPLC separation was achieved using Nucleosil C18 column and
acetonitrile/methanol/isopropyl alcohol (55:41:4 by volume) mixture as the mobile
phase, the pH was adjusted to 8 ± 0.1 with triethylamine and the flow rate was 1.2
mL/min. The detection wavelengths were chosen to be 238, 248 and 271 nm for
Amlodipine, Valsartan and Hydrochlorothiazide, respectively. The linearity of the
proposed method was established over the ranges, 2.0–28.0, 10.0–120.0 and 0.6–
32.0 µg/mL for Amlodipine, Valsartan and Hydrochlorothiazide, respectively. For the
densitometric TLC method, silica gel 60 F254 plates were used and ethyl
acetate/toluene/methanol/ammonia (50.5:23.5:23.5:2.5 by volume) mixture as the
developing solvent. Detection and quantification were performed densitometrically at
252 nm. The linearity of the proposed method was established over the ranges, 0.5-
9.0, 4.0-18.0 and 3.0-11.0 µg/band for Amlodipine, Valsartan and
Hydrochlorothiazide, respectively.
Darwish, H. W., S. A. Hassan, M. Y. Salem, and B. A. El-Zeany,
"Comparative study between derivative spectrophotometry and multivariate calibration as analytical tools applied for the simultaneous quantitation of Amlodipine, Valsartan and Hydrochlorothiazide",
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 113, pp. 215–223, 2013.
AbstractFour simple, accurate and specific methods were developed and validated for the simultaneous estimation of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in commercial tablets. The derivative spectrophotometric methods include Derivative Ratio Zero Crossing (DRZC) and Double Divisor Ratio Spectra-Derivative Spectrophotometry (DDRS-DS) methods, while the multivariate calibrations used are Principal Component Regression (PCR) and Partial Least Squares (PLSs). The proposed methods were applied successfully in the determination of the drugs in laboratory-prepared mixtures and in commercial pharmaceutical preparations. The validity of the proposed methods was assessed using the standard addition technique. The linearity of the proposed methods is investigated in the range of 2–32, 4–44 and 2–20 μg/mL for AML, VAL and HCT, respectively.
Darwish, H. W., S. A. Hassan, M. Y. Salem, and B. A. El-Zeany,
"Sequential Spectrophotometric method for the simultaneous determination of Amlodipine, Valsartan and Hydrochlorothiazide in co-formulated tablets",
International Journal of Spectroscopy, vol. 2013, issue Article ID 273102, 2013.
AbstractA new, simple and specific spectrophotometric method was developed and validated in accordance with ICH guidelines for the simultaneous estimation of Amlodipine (AML), Valsartan (VAL), and Hydrochlorothiazide (HCT) in their ternary mixture. In this method three techniques were used, namely, direct spectrophotometry, ratio subtraction, and isoabsorptive point. Amlodipine (AML) was first determined by direct spectrophotometry and then ratio subtraction was applied to remove the AML spectrum from the mixture spectrum. Hydrochlorothiazide (HCT) could then be determined directly without interference from Valsartan (VAL) which could be determined using the isoabsorptive point theory. The calibration curve is linear over the concentration ranges of 4–32, 4–44 and 6–20 μg/mL for AML, VAL, and HCT, respectively. This method was tested by analyzing synthetic mixtures of the above drugs and was successfully applied to commercial pharmaceutical preparation of the drugs, where the standard deviation is <2 in the assay of raw materials and tablets. The method was validated according to the ICH guidelines and accuracy, precision, repeatability, and robustness were found to be within the acceptable limits.
