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Aims: Novel green analytical methods have been proposed for the assay of Rabeprazole sodium and Fluvastatin sodium in their pure and formulated dosage forms. Study Design: The methods determine each drug through the estimation of its sodium content, using Flame Atomic Absorption Spectroscopy at wavelength 589 nm. Place and Duration of Study: Central laboratory at Faculty of Pharmacy, Damanhour University. Time duration January-March, 2020. Methodology: Methods are developed and optimized for maximum sensitivity, selectivity and degree of greenness. Linearity is achieved in the range of 8.29- 66.33 ppm of Rabeprazole sodium (equivalent to 0.5- 4 ppm Na) and 14.13- 141.32 ppm of Fluvastatin sodium (equivalent to 0.75 -7.5 ppm Na). The proposed assays are fully validated regarding ICH guidelines. Results: Atomic spectroscopic assays are compared to reported spectrophotometric ones for each drug separately using Student t-test and F-variance ratio. Conclusion: Satisfactory values indicate good agreement and the insignificant difference between both methods. The obtained percentages of recovery (99-101%) indicate no interference from excipients in formulation matrices.

A new, simple, stability-indicating high-performance thin-layer chromatography method was developed for the quantification of 10-hydroxy-2-decenoic acid (10-HDA) in some royal jelly products marketed in Egypt. The used solvent system was chloroform:acetic acid (10:1, v/v) and the bands were measured densitometrically at 210 nm. First- and second-derivative treatments of the data were performed. The present study shows a comparison between three statistical regression methods for handling data: parametric, nonparametric and weighted regression (WR) methods. The developed methods were validated as per International Conference on Harmonization guidelines. To validate the stability-indicating power of the developed analytical method, the royal jelly standard was subjected to forced degradation studies including the effect of hydrolysis, oxidation, photolysis and dry heat. It was found that derivative treatment of the chromatographic response data gives improved quantitation and sensitivity of the chromatographic signals. Weighted regression of the response data is found to be advantageous over the use of both parametric and nonparametric regression models. This was shown by a great enhancement in the accuracy and precision in the analysis of 10-HDA in royal jelly products. The % recovery in case of WR was 99.92 ± 0.16, while % recovery in case of nonparametric and parametric regressions were 99.56 ± 0.25 and 98.63 ± 0.65, respectively.

The two stereo-isomers; quinine and quinidine have been determined in their mixtures in the IR region using chemometric multivariate methods, principal component regression (PCR) and partial least squares (PLS). A training set of thirty synthetic binary mixture solutions in the possible combinations containing 0.0 - 4.0 and 4.0 - 0.0% w/v quinine and quinidine, respectively in chloroform was used to develop the multivariate calibrations. A validation set containing thirty synthetic binary mixtures of variable ratios in the range of 0.2 - 4.0 and 4.0 - 0.2% w/v for quinine and quinidine, respectively in chloroform was used to validate the developed calibrations. The results of analysis of the validation synthetic mixtures were found to be 100.5+/-0.44% (R.S.D.%=0.44) and 100.5+/-0.38% (R.S.D.%=0.38) for quinine and 100.1+/-0.67% (R.S.D.%=0.67) and 100.1+/-0.68% (R.S.D.%=0.68) for quinidine using PCR and PLS models, respectively.

Chemometric spectrophotometry and HPLC were applied to the simultaneous determination of the two non-steroidal anti-inflammatory drugs; diflunisal (I) and naproxen (II). The applied chemometric techniques are multivariate methods including classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS); and the second derivative of the ratio spectra ((2)D(r)) method. To develop the multivariate methods, the UV absorption spectra of the standard solutions of the training and validation sets in methanol were recorded in the range of 242-274 nm at 2 nm intervals. The specificity of the studied multivariate methods has been tested. In the (2)D(r) method, analytical signals at 235 and 259 nm were selected for the determination of (I) and (II), respectively. The HPLC method depends on reversed-phase separation using C18 column. The mobile phase consists of a mixture of acetonitrile - acetate buffer (pH 4.2; 50 mM) (60:40, v/v). The UV detector was set at 255 nm. The developed methods were validated and successfully applied to the simultaneous determination of (I) and (II) in their tablets. The assay results obtained using the chemometric methods were statistically compared to those of the HPLC method and good agreement was observed.

Chemometric stability indicating methods are presented for the determination of rabeprazole sodium in presence of its acid induced degradation products using spectrophotometry, differential pulse polarography and differential pulse anodic voltammetry at a glassy carbon electrode. The applied chemometric techniques are multivariate ones including classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS). A difference spectrophotometric (DeltaA) method has also been applied. To develop the multivariate calibrations, a training set was used, consisting of 20 mixture solutions of rabeprazole sodium and its degradation products. These mixtures show percentage degradation ranging from 0.5-65%, 0.5-95% and 0.6-75% for the spectrophotometric, polarographic and anodic voltammetric calibrations, respectively. The UV absorbances were recorded in 0.1 M NaOH within the wavelength range 220-340 nm at 2 nm intervals. The polarograms and anodic voltammograms were recorded in Britton-Robinson buffer (pH 8.0) within the potential range -500 to -1508 and 400 to 1192 mV at 6 mV intervals with a pulse amplitude of -100 and 50 mV, sweep rate of 15 and 10 mV s(-1) and pulse interval of 0.4 and 0.6 s for the polarographic and anodic voltammetric methods, respectively. All the studied methods have been validated and successfully applied to the determination of rabeprazole sodium in tablet dosage form. The results were statistically compared to those obtained using a published HPLC method. No significant difference has been found.