Feyyaz Onur

Spectrophotometric multicomponent determination of sunset yellow, tartrazine and allura red in soft drink powder by double divisor-ratio spectra derivative, inverse least-squares and principal component regression methods

Double divisor-ratio spectra derivative (graphical method), classical least-squares and principal component regression (two numerical methods) methods were developed for the spectrophotometric multicomponent analysis of soft drink powders and synthetic mixtures containing three colorants without any chemical separation. The graphical method is based on the use of derivative signals of the ratio spectra using double divisor. In this method, the linear determination ranges were 2-8 mug ml(-1) sunset yellow, 4-18 mug ml(-1) tartrazine and 2-8 mug ml(-1) allura red in 0.1 M HCl. In the numerical methods, a training set was randomly prepared by using 18 samples containing between 0 and 8 mug ml(-1) of sunset yellow, 0-18 mug ml(-1) of tartrazine and 0-8 mug ml(-1) of allura red. The chemometric calibrations were calculated by using the prepared training set and its absorbances at seven points (from 375.0 to 550.0 nm) in the spectral region 325-584 nm. The proposed methods were validated by using synthetic ternary mixtures and applied to the simultaneous determination of three colorants in soft drink powders. The obtained results were statistically compared with each other.

Application of a new spectrophotometric method for the analysis of a ternary mixture containing metamizol, paracetamol and caffeine in tablets

A new spectrophotometric method was developed for the simultaneous analysis of a ternary mixture, without prior separation. This method is based on the use of the derivative of the ratio spectrum obtained by dividing the absorption spectrum of the ternary mixture by a standard spectrum of a mixture of two of the three compounds in the title mixture. The concentrations of three compounds in their mixture are determined by using their respective calibration graphs which are obtained by measuring the amplitude at either the maximum or minimum wavelengths selected. The mathematical explanation of the procedure is illustrated. The method was applied for the assay of tablets containing metamizol, caffeine and paracetamol. The developed method was compared with alternative spectrophotometric methods.

Simultaneous spectrophotometric determination of mefenamic acid and paracetamol in a pharmaceutical preparation using ratio spectra derivative spectrophotometry and chemometric methods

Four new methods are described for the simultaneous determination of mefenamic acid (MEF) and paracetamol (PAR) in their combination. In the first method, ratio spectra derivative method, analytical signals were measured at the wavelengths corresponding to either maximums or minimums for both drugs in the first derivative spectra of the ratio spectra obtained by dividing the standard spectrum of one of two drugs in 0.1 M NaOH:methanol (1:9). In the chemometric techniques, classical least-squares, inverse least-squares and principal component regression (PCR), the training was randomly prepared by using the different mixture compositions containing two drugs in 0.1 M NaOH:methanol (1:9). The absorbance data was obtained by the measurements at 13 points in the wavelength range 235-355 nm in the absorption spectra. Chemometric calibrations were constructed by the absorbance data and training set for the prediction of the amount of MEF and PAR in samples. In the third chemometric method, PCR, the covariance matrix corresponding to the absorbance data was calculated for the basis vectors and matrix containing the new coordinates. The obtained calibration was used to determine the title drugs in their mixture. Linearity range in all the methods was found to be 2-10 microg/ml of MEF and 4-20 microg/ml of PAR. Mean recoveries were found satisfactory (>99%). The procedures do not require any separation step. These methods were successfully applied to a pharmaceutical formulation, tablet, and the results were compared with each other.

Simultaneous spectrophotometric determination of pseudoephedrine hydrochloride and ibuprofen in a pharmaceutical preparation using ratio spectra derivative spectrophotometry and multivariate calibration techniques.

Spectrophotometric methods are described for the simultaneous determination of pseudoephedrine hydrochloride and ibuprofen in their combination. The obtained data were evaluated by using five different methods. In the first method, ratio spectra derivative spectrophotometry, analytical signals were measured at the wavelengths corresponding to either maximums and minimums for both drugs in the first derivative spectra of the ratio spectra obtained by using each other spectra as divisor in their solution in 0.1 M HCl. In the other four spectrophotometric methods using chemometric techniques, classical least-squares, inverse least-squares, principal component regression and partial least-squares (PLS), the concentration data matrix were prepared by using the synthetic mixtures containing these drugs in methanol:0.1 M HCl (3:1). The absorbance data matrix corresponding to the concentration data matrix was obtained by the measurements of absorbances in the range 240-285 nm in the intervals with deltalambda = 2.5 nm at 18 wavelengths in their zero-order spectra, then, calibration or regression was obtained by using the absorbance data matrix and concentration data matrix for the prediction of the unknown concentrations of pseudoephedrine hydrochloride and ibuprofen in their mixture. The procedures did not require any separation step. The linear range was found to be 300-1300 microg/ml for ibuprofen and 100-1300 microg/ml for pseudoephedrine hydrochloride in all five methods. The accuracy and the precision of the methods have been determined and they have been validated by analyzing synthetic mixtures. The five methods were successfully applied to tablets and the results were compared with each other.

Simultaneous determination of pseudoephedrine sulfate, dexbrompheniramine maleate and loratadine in pharmaceutical preparations using derivative spectrophotometry and ratio spectra derivative spectrophotometry

Two new spectrophotometric methods are described for the simultaneous analysis of pseudoephedrine sulfate-dexbrompheniramine maleate (DBP) and pseudoephedrine sulfate-loratadine combinations. In the first, derivative spectrophotometry, dA/dlambda values were read at zero-crossing points. In the second, ratio spectra derivative spectrophotometry, analytical signals were measured at the wavelengths corresponding to either maxima or minima for these drugs in the first derivative spectra of their ratio spectra. The procedures do not require any separation step. Mean recoveries were found to be >99% in the methods for these compounds in their synthetic mixtures. All the spectrophotometric methods proposed were compared with each other and HPLC which was also developed by us and applied to the pharmaceutical preparations selected.

Derivative ratio spectra-zero crossing spectrophotometry and LC method applied to the quantitative determination of paracetamol, propyphenazone and caffeine in ternary mixtures.

Two methods were used to determine paracetamol, caffeine and propyphenazon in ternary mixtures and tablets. Derivative ratio spectra-zero crossing procedure was based on the simultaneous use of the first derivative of ratio spectra and measurements of derivative ratio analytical signals corresponding to the zero crossing points of wavelengths. By using propyphenazon as a divisor, the amounts of paracetamol and caffeine in the ternary mixture were determined by measuring the first derivative ratio amplitudes at 242.8 nm (zero-crossing point for caffeine) and 251.2 and 273.8 nm (zero-crossing point for paracetamol) respectively. Also by using paracetamol as a divisor, the contents of propyhenazon and caffeine in the same ternary mixture were determined by measuring the first derivative ratio amplitudes at 244.8 and 276.9 nm (zero-crossing point for caffeine) and 250.6 and 274.0 nm (zero-crossing point for propyphenazon), respectively. For the HPLC procedure, a Nucleosil C18 column and a mobile phase consisted of water and methanol (20:80) were used to separate three compounds with cetrimide as an internal standard. The flow rate was 1.0-ml/min with an ultraviolet (UV) detection at 254 nm. Both methods were also applied to the determination of these three compounds in ternary mixtures and tablet formulation. The analytical results were quite good in all cases.

Simultaneous spectrophotometric determination of chlorphenoxamine hydrochloride and caffeine in a pharmaceutical preparation using first derivative of the ratio spectra and chemometric methods

Three new methods are described for the simultaneous determination of chlorphenoxamine hydrochloride (CP) and caffeine (CAF) in their combination. In the first method, ratio spectra derivative spectrophotometry, analytical signals were measured at the wavelengths corresponding to either maxima and minima for both drugs in the first derivative spectra of the ratio spectra obtained by using each other spectra as divisor in their solution in 0.1 M HCl. In the other two methods, chemometric techniques, classical least-squares (CLS) and inverse least-squares (ILS), the concentration data matrix were prepared by using the synthetic mixtures containing these drugs in 0.1 M HCl. The absorbance data matrix corresponding to the concentration data matrix was obtained by the measurements of absorbances in the range 225-285 nm in the intervals with Deltalambda = 5 nm at 13 wavelengths in their zero-order spectra, then, calibration or regression was obtained by using the absorbance data matrix and concentration data matrix for the prediction of the unknown concentrations of CP and CAF in their mixture. The numerical values were calculated by using MAPLE V software in chemometric methods. The procedures do not require any separation step. The accuracy and the precision of the methods have been determined and they have been validated by analyzing synthetic mixtures containing title drugs. These three methods were successfully applied to a pharmaceutical formulation, sugar-coated tablet, and the results were compared with each other.

CHEMOMETRIC QUANTITATIVE ANALYSIS OF PYRIDOXINE HCl AND THIAMINE HCl IN A VITAMIN COMBINATION BY PRINCIPAL COMPONENT ANALYSIS, CLASSICAL LEAST SQUARES, AND INVERSE LEAST SQUARES TECHNIQUES

Three chemometric techniques were described for the analysis of pyridoxine hydrochloride and thiamine hydrochloride within a vitamin combination in the presence of spectral interferences. For these techniques, the training set was prepared by using synthetic mixtures containing two vitamins in multiple possible combinations for the range of 8–40 μ/mL in 0.1 M HCl. The absorbance values for the training set were obtained by direct measurements at 18 wavelengths in the region 222–305 nm for the zero order spectra. The numerical values were calculated by using the ‘Maple V’ software. Mean recoveries and relative standard deviations for the principal component analysis, classical least squares and inverse least squares techniques were found as 100.7% and 0.95%; 100.5% and 1.38% and, 99.3% and 1.04 for pyridoxine hydrochloride; and 99.7% and 1.03%; 99.1% and 1.05% and, 99.6% and 1.58% for thiamine hydrochloride, respectively. These three chemometric techniques were successfully applied to vitamin tablets marketed in Turkey. The results were compared with each other and good coincidence was observed.

Application of Derivative and Ratio Spectra Derivative Spectrophotometry for the Determination of Pseudoephedrine Hydrochloride and Acrivastine in Capsules

Abstract Two new spectrophotometric methods are used for the determination of acrivastine and pseudoephedrine hydochloride in their mixture without previous chemical separation. In the first, second derivative spectrophotometry, the measurements are made at 288.0 nm for acrivastine and at 270.2 nm for pseudoephedrine hydrochloride in the second derivative spectra of their solution in 0.1M NaOH. In the second, ratio spectra derivative spectrophotometry, the amplitudes are measured at 276.0 nm and 298.5 nm corresponding to two maximums for acrivastine, and at 252.6 nm and 268.3 nm corresponding to a maximum and a minumum, respectively, for pseudoephedrine hydrochloride in first derivative of their ratio spectra plotted by using of their solutions as divisor. The methods were successfully applied for the determination of these drugs in a commercial pharmaceutical formulation capsule.

Three New Spectrophotometric Methods for Simultaneous Determination of Hydrochlorothiazide and Amiloride Hydrochloride in Sugar-Coated Tablets

Abstract Three new spectrophotometric methods. Vierordts method, its modified version and the absorbancy ratio method have been used for the simultaneous determination of hydrochlorothiazide and amiloride hydrochloride in binary mixtures. Mean recoveries, relative standard deviations and linearity ranges in calibration graphs of the methods were compared. These three methods have been successfully applied to a commercial pharmaceutical preparation, a sugar - coated tablet containing hydrochlorothiazide and amiloride hydrochloride.