The Resolution of Dye Binary Mixtures by Bivariate Calibration Using Spectrophotometric Data

Comparative study of novel green UV-spectrophotometric platforms for simultaneous rapid analysis of flumethasone pivalate and clioquinol in their combined formulation

Flumethasone pivalate (FP) and clioquinol (CL) formulation was developed as a prodigious remedy to cure the external ear inflammatory disorders. So, the current research introduces five smart and novel UV-spectrophotometric platforms relying on minimal mathematical manipulation steps for simultaneous green analysis of FP and CL with no preliminary separation in their formulation that suffered from the high difference of their ratio and severe spectral overlapping. These platforms involved dual-wavelength, first derivative ratio, Fourier self-deconvolution, area under the curve, and bivariate methods. The suggested platform' linearity was observed over the concentration range of 3-42 µg/ml for FP and 1.5-8 µg/ml for CL. All suggested platforms were validated according to ICH recommendations regarding accuracy, precision, repeatability, and selectivity producing satisfactory results within the accepted limits. These platforms were represented as rapid, green, and cheap alternatives to the reported chromatographic method due to lower solvent consumption and waste generation. Furthermore, they improved the determination sensitivity of the studied drugs and enhanced the recorded data signals or its spectral resolution by the newly introduced Fourier self-deconvoluted method. The statistical comparison between the results of the suggested platforms with each other and with those of the reported method showed no significant differences between them.

Simultaneous determination of Nebivolol hydrochloride and Valsartan in their binary mixture using different validated spectrophotometric methods

Five simple, sensitive, accurate and precise spectrophotometric methods were developed for the simultaneous determination of Nebivolol hydrochloride (NEB) and Valsartan (VAL) in their binary mixtures and in pharmaceutical dosage form. The methods included Ratio Difference, First Derivative ratio, Mean Centering of ratio spectra, Bivariate and H-Point Standard additions method. The calibration curves were linear over the concentration range of 10-70 μg/ml and 20-60 μg/ml for NEB and VAL, respectively for Ratio Difference and First Derivative ratio method and over the concentration range of 10-70 μg/ml and 10-60 μg/ml for NEB and VAL, respectively for Mean Centering of ratio spectra, Bivariate and H-Point Standard additions method. These methods were examined by analyzing synthetic mixtures of the studied drugs and they were utilized to determine the studied drugs in their commercial pharmaceutical preparation. All methods were validated as per ICH guidelines and accuracy, robustness, repeatability and precision were found to be within the acceptable limits. The results of the proposed methods were compared to the results of reported methods with no significant difference between them.

Stability indicating methods for the analysis of cefprozil in the presence of its alkaline induced degradation product

Three simple, specific, accurate and precise spectrophotometric methods were developed for the determination of cefprozil (CZ) in the presence of its alkaline induced degradation product (DCZ). The first method was the bivariate method, while the two other multivariate methods were partial least squares (PLS) and spectral residual augmented classical least squares (SRACLS). The multivariate methods were applied with and without variable selection procedure (genetic algorithm GA). These methods were tested by analyzing laboratory prepared mixtures of the above drug with its alkaline induced degradation product and they were applied to its commercial pharmaceutical products.

A comparative study between three stability indicating spectrophotometric methods for the determination of diatrizoate sodium in presence of its cytotoxic degradation product based on two-wavelength selection

Three sensitive, selective, and precise stability indicating spectrophotometric methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA) in the presence of its acidic degradation product (highly cytotoxic 3,5-diamino metabolite) and in pharmaceutical formulation, were developed and validated. The first method is ratio difference, the second one is the bivariate method, and the third one is the dual wavelength method. The calibration curves for the three proposed methods are linear over a concentration range of 2-24 μg/mL. The selectivity of the proposed methods was tested using laboratory prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

Novel two wavelength spectrophotometric methods for simultaneous determination of binary mixtures with severely overlapping spectra

This work presents the application of different spectrophotometric techniques based on two wavelengths for the determination of severely overlapped spectral components in a binary mixture without prior separation. Four novel spectrophotometric methods were developed namely: induced dual wavelength method (IDW), dual wavelength resolution technique (DWRT), advanced amplitude modulation method (AAM) and induced amplitude modulation method (IAM). The results of the novel methods were compared to that of three well-established methods which were: dual wavelength method (DW), Vierordt's method (VD) and bivariate method (BV). The developed methods were applied for the analysis of the binary mixture of hydrocortisone acetate (HCA) and fusidic acid (FSA) formulated as topical cream accompanied by the determination of methyl paraben and propyl paraben present as preservatives. The specificity of the novel methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

Three different methods for determination of binary mixture of Amlodipine and Atorvastatin using dual wavelength spectrophotometry

Three simple, specific, accurate and precise spectrophotometric methods depending on the proper selection of two wavelengths are developed for the simultaneous determination of Amlodipine besylate (AML) and Atorvastatin calcium (ATV) in tablet dosage forms. The first method is the new Ratio Difference method, the second method is the Bivariate method and the third one is the Absorbance Ratio method. The calibration curve is linear over the concentration range of 4-40 and 8-32 μg/mL for AML and ATV, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. Methods are validated according to the ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit. The mathematical explanation of the procedures is illustrated.

An application of UV-derivative spectrophotometry and bivariate calibration algorithm for study of photostability of levomepromazine hydrochloride

Derivative spectrophotometry and bivariate calibration algorithm were used for study of run of photooxidation of levomepromazine hydrochloride (LV). The actual concentrations of LV and its main degradation product levomepromazine sulphoxide (LV-SO) were calculated using data provided by applied methods. The direct reading of absorbance values at 302 nm and 334 nm were employed for quantification of LV and LV-SO, respectively, in the case of bivariate method. The derivative spectrophotometric method is based on transformation of zero-order spectra into first derivative. The values of first derivative at 334 nm were used for quantification of LV while at 278 nm for assay of LV-SO. The obtained quantitative data were applied for investigation of kinetics of photodegradation of LV.

Simultaneous determination of nifuroxazide and drotaverine hydrochloride in pharmaceutical preparations by bivariate and multivariate spectral analysis

The quantitative predictive abilities of the new and simple bivariate spectrophotometric method are compared with the results obtained by the use of multivariate calibration methods [the classical least squares (CLS), principle component regression (PCR) and partial least squares (PLS)], using the information contained in the absorption spectra of the appropriate solutions. Mixtures of the two drugs Nifuroxazide (NIF) and Drotaverine hydrochloride (DRO) were resolved by application of the bivariate method. The different chemometric approaches were applied also with previous optimization of the calibration matrix, as they are useful in simultaneous inclusion of many spectral wavelengths. The results found by application of the bivariate, CLS, PCR and PLS methods for the simultaneous determinations of mixtures of both components containing 2-12microgml(-1) of NIF and 2-8microgml(-1) of DRO are reported. Both approaches were satisfactorily applied to the simultaneous determination of NIF and DRO in pure form and in pharmaceutical formulation. The results were in accordance with those given by the EVA Pharma reference spectrophotometric method.

Chemometric and derivative methods as flexible spectrophotometric approaches for dissolution and assaying tests in multicomponent tablets

Two derivative spectrophotometric (ratio derivative spectra and algorithm bivariate calibration) and a chemometric methods (partial least squares, PLS) are proposed for the simultaneous determination of binary mixtures in tablet analysis and dissolutions tests, without prior separation. These approaches are successfully applied to quantify trimethoprim (TMP) combined with sulfamethoxazole (SMX) or sulfamethazine (SMZ) or sulfafurazole (SFZ) using the information in the absorption spectra of appropriate solutions. Beer's law was obeyed in the concentration range of 0.98-17.5 microg/ml for TMP, 0.95-17.2 microg/ml for SMX, 1.16-17.5 microg/ml for SMZ and 0.97-17.4 microg/ml for SFZ. The first derivative (1D) bivariate algorithm method involves the use of four calibration curves: two for each compound at two different wavelengths, selected by Kaiser's method. Similarly, the first derivative ratio spectrophotometry employs the linear relationship between the ratio spectra of the analytes and the concentration range. The results were compared with those obtained by PLS multivariate calibration. The calibration models from PLS were pre-treated by orthogonal signal correction and evaluated by cross-validation using the 'SIMCA-P 9' software. Synthetic mixtures of TMP and sulfonamides were used in five different sets for the validity of the calibrations. Mean recoveries for derivative ratio, derivative bivariate and PLS methods were found to be between 99.7% and 102.0% for TMP, 99.4% and 100.2% for SMX, 99.3% and 101.0% for SMZ and 98.1% and 102.3% for SFZ. The calibrations of the three methods were successfully applied to the assaying and dissolution of placebo and commercial tablets without any prior separation. More than 85% of TMP, SMX and SMZ were dissolved within 15 min. For SFZ, only 85% of the compound was dissolved after 60 min. In this study, the three spectrophotometric methods can be satisfactorily used for the quantitative analysis and for dissolution tests of multicomponent dosage forms.

Two derivative spectrophotometric methods for the simultaneous determination of lovastatin combined with three antioxidants

A zero crossing and an algorithm bivariate calibration derivative method for the simultaneous determination of lovastatin combined separately with three antioxidants (ascorbic acid, quercetin and gallic acid) in synthetic mixtures are described. The aqueous or methanolic solutions obeyed Beer's law in the concentration ranges of 3.20-17.36 microg/ml for lovastatin, 1.76-8.80 microg/ml for ascorbic acid, 1.41-7.04 microg/ml for gallic acid and 1.84-9.20 microg/ml for quercetin, for both methods, respectively. In the second derivative (2D) zero crossing method measurements were carried out at 238.4 nm for lovastatin and 265.6 nm for ascorbic acid, 247.7 nm for lovastatin and 281.1 nm for quercetin, 251.8 nm for lovastatin and 267.6 nm for gallic acid. In the first derivative (1D) bivariate spectrophotometric method an optimum pair of wavelengths was chosen for the determination of different binary mixtures. The proposed procedures were successfully applied to the simultaneous determination of lovastatin and different antioxidants in mixtures with high percentage of recovery, 98.3-100.4% for lovastatin, 98.3-98.6% for ascorbic acid, 99.0-99.8% for quercetin and 100.5-101.1% for gallic acid and good precision. In addition, the results from the above procedures were verified by using partial least-squares (PLS) multivariate calibration method.

Simultaneous determination of binary mixtures of trimethoprim and sulfamethoxazole or sulphamethoxypyridazine by the bivariate calibration spectrophotometric method

The bivariate calibration algorithm was applied to the spectrophotometric simultaneous determination of trimethoprim (TMP), sulfamethoxazole (SMX) or sulphamethoxypyridazine (SMP) binary mixtures in pharmaceutical and veterinary products. The results obtained were compared with those from derivative spectrophotometry. The statistical evaluation of the method bias showed that the proposed procedure is comparable with commonly used first-derivative spectrophotometry. However, the advantage of bivariate calibration is its simplicity, due to the minimal spectra manipulation when compared with derivative techniques.

Application of the bivariate spectrophotometric method for the determination of metronidazole, furazolidone and di-iodohydroxyquinoline in pharmaceutical formulations

The bivariate calibration algorithm was applied to the spectrophotometric determination of metronidazole, furazolidone and di-iodohydroxyquinoline in pharmaceutical dosage forms. The results obtained were compared with the results of derivative spectrophotometry. The statistical evaluation of method bias was carried out, and it was shown that the proposed procedure may be competitive with commonly used first-derivative spectrophotometry. The advantage of the bivariate calibration is its simplicity, and the fact that there is no need to use the derivatization procedures.