WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Citation - WoS: 8Citation - Scopus: 8Determination of Salicin Content of Some Salix L. Species by Hplc Method(Chiminform Data S A, 2007) Guvenc, Aysegul; Baleanu, Dumitru; Arihan, Okan; Altun, M. Levent; Dinc, Erdal; Baleanu, Dumitru; MatematikIn this paper, we find the salicin content of the nine species of Salix L from the province of Ankara, Turkey, namely Salix triandra, S. alba, S. excelsa, S. fragilis, S. babylonica, S. caprea, S. cinerea, S. pseudomedemii and S. amplexicaulis. A simple HPLC method was applied to the determination of Salicin of these nine species in barks and leaves of female and male. Chromatographic separation was carried out by a mobile phase consisting of bidistilled water, tetrahydrofuran and ortho-phosphoric acid (97.7: 1.8: 0.5) (v/v/v). The salicin amount of these samples was analyzed by measuring the peak area at the wavelength, 270 nm. A reversed phase phenyl column (250 x 4.6mm, 5 mu m) was used and flow rate was set to 1 ml/min. in an isocratic elution. The results provided 6 HPLC method was found in agreement with those indicated by European Pharmacopoeia. It was observed that S. babylonica female bark sample possess the highest salicin content (2.675), while S. caprea female bark (0.058) has the lowest salicin content as w/w (%).Article Citation - WoS: 7Citation - Scopus: 6Simultaneous Determination of Chlorotetracycline and Benzocaine in Bolus by Chemometric Methods(Chiminform Data S A, 2007) Dinc, Erdal; Baleanu, Dumitru; Kanbur, Murat; Baleanu, Dumitru; MatematikTwo chemometric methods were applied to the simultaneous determination of chlortetracycline (CTC) and benzocaine (BC) in their binary mixture. The methods involve multivariate calibration based on principal least-squares (PCR) and partial least-squares (PLS) regressions. A concentration set consisting of binary mixtures of CTC and BC in 13 different combinations were randomly prepared in 0,011 M HCl. Both multivariate calibration models were constructed by using the relationship between the concentration set and its corresponding absorption data in the spectral region of 200-305 nm, The accuracy and the precision of the methods were validated by analyzing synthetic mixtures containing investigated drugs. The recovery results obtained by applying PCR and PLS calibrations to artificial mixtures were found between 100.2 and 101.0%. Data treatments, regressions and statistical analysis were performed by using the Microsoft EXCEL and PLS toolbox 3.5 in Matlab 7.0 software. Satisfactory results for both artificial and commercial veterinary samples were obtained. The experimental results from two chemometric methods were compared with each other.Article Citation - WoS: 3Citation - Scopus: 5Simultaneous Determination of Quinapril and Hydrochlorothiazide in Tablets by Ratio Spectra Derivative Spectrophotometric and Chemometric Methods(Chiminform Data S A, 2007) Dinc, Erdal; Baleanu, Dumitru; Altynoz, Sacide; Baleanu, Dumitru; MatematikSimultaneous determination of quinapril (QA) and hydrochlorothiazide (HCT) in tablets were accomplished by ratio spectra first order derivative spectrophotometry (graphical method) and chemometric method (numerical method). Both methods do not require any chemical separation step. In the application of two analytical methods, the absorption spectra in the working range of 4.0-20.0 mu g/mL QA and 2.5-12.5 mu g/mL HCT were plotted in the wavelength range of 210-350 nm. In the graphical approach, the absorption spectra of QA and its binary mixtures in the selected spectral range of 210-280 nm were divided by the standard spectrum of 10 mu g/ mL HCT and their absorption spectra were obtained. In the similar way, the ratio spectra of HCT in the wavelength region of 210-350 nm were also obtained by using the standard spectrum of 12 mu g/mL QA. First derivative of the ratio spectra obtained in the above steps were calculated by Delta lambda=5 nm interval for both drugs. Calibration equation functions were obtained by measuring (he ratio spectra derivative amplitudes of the minima at 219.9 nm for QA and 283.2 nm for HCT in the above mentioned spectral ranges for each drug. In the numerical method, the critical wavelengths corresponding to maximum points at 213.0 nm for QA and 220.0 nm for HCT in the zero-order absorption spectra were selected to construct the least squares calibration (CLS). Both graphical and numerical methods developed in this study were completely validated and applied to the quantitative analysts of tablets containing QA and HCT The results obtained from the developed methods were compared with each other as well as to those obtained by classical derivative spectrophotometry, which have different experimental conditions than the previous derivative method, and the difference was not observed statistically significant.Article Citation - WoS: 5Citation - Scopus: 5Spectral Continuous Wavelet Transform for the Simultaneous Spectrophotometric Analysis of a Combined Pharmaceutical Formulation(Chiminform Data S A, 2009) Dinc, Erdal; Baleanu, Dumitru; Baleanu, Dumitru; MatematikContinuous wavelet transform (CWT) combined with zero crossing technique was proposed for the simultaneous spectrophotometric determination of telmisartan (TMS) and hydrochlorothiazide (HCT) in their binary mixtures without using a chemical pretreatment. This new hybrid analytical approach is based on the application of the CWT method to the absorption spectra of the analytes and their samples. In the signal analysis, Gaussian (GAUS3) with order 3 and BiorSplines (BIOR1.2) with 1.2 order were found to be suitable for the quantitative spectral resolution of TMS and HCT in samples. These hybrid approaches were named as GAUS3-CWT and BIOR1.2-CWT The validation of the CWT signal processing methods was carried out by using various binary mixtures of the analytes. The amounts of TMS and HCT in tablets were successfully determined by using the proposed GAUS3-CWT and BIOR1.2-CWT tools.Article Citation - WoS: 2Citation - Scopus: 3An Application of Principal Component Analysis - Artificial Neural Network for the Simultaneous Quantitative Analysis of a Binary Mixture System(Chiminform Data S A, 2009) Dinc, Erdal; Baleanu, Dumitru; Sen Koktas, Nigar; Köktaş, Nigar; Baleanu, Dumitru; Kökias, Nigar Şen; MatematikArtificial neural networks (ANNs) based on the use of principal components and the original absorbance data were proposed for the simultaneous quantitative analysis of amlodipine (AML) and atorvastatin (ATO) in tablets. A concentration set of mixtures containing ATO and AML in different concentration composition between 0.0-20.0 mu g/mL was prepared in methanol. The measured absorbance data matrix for the concentration data set was obtained and the principal components were extracted. In the next step five principal components were selected as an input data for the artificial neural network. This combined approach was named principal components-artificial neural network (PCA-ANN). The same problem was solved by using the application of the artificial neural network to the original absorbance data matrix. This approach was denoted as ANN. The classical ANN approach was used as a comparison method. Both PCA-ANN and ANN methods were tested by analyzing various synthetic mixtures corresponding to the validation set of AML and ATO compounds. The proposed methods were successfully applied to the quantitative analysis of the commercial tablets and a coincidence was reported between the proposed methods.Article Citation - WoS: 1Citation - Scopus: 2Wavelet Transform With Chemometrics Techniques for Quantitative Multiresolution Analysis of a Ternary Mixture Consisting of Paracetamol, Ascorbic Acid and Acetylsalicylic Acid in Effervescent Tablets(Chiminform Data S A, 2006) Baleanu, Dumitru; Dinc, Erdal; Ozdemir, Abdil; Taş, Kenan; Baleanu, Dumitru; Tas, Kenan; MatematikQuantitative multiresolution analysis of paracetamol (PAR), ascorbic acid (AA) and acetylsalicylic acid (ASP) in pharmaceutical samples was carried out by using simultaneous use of discrete wavelet transformation (DWT) and afterward partial least squares (PLS) and classical least squares (CLS) techniques. The desired concentration was obtained using a set of 20 different calibration samples of PAR, AA, and ASP in different concentration ratio. The absorption spectra in the spectral range of 220-305 nm were recorded and their absorption values were measured at 850 points with intervals of Delta lambda = 0. 1 nm. The obtained DWT-CLS and DWT-PLS calibrations were tested by analysing the independent synthetic mixture containing the above subject compounds. The experimental results showed that DWT-CLS and DWT-PLS techniques are suitable for simultaneous determination of PAR, AA and ASP in samples. The obtained results were compared with those in literature.Article Citation - WoS: 16Citation - Scopus: 13Wavelet Transform and Artificial Neutral Network for the Quantitative Resolution of Ternary Mixtures(Revista Chimie Srl, 2006) Dinc, Erdal; Baleanu, Dumitru; Baleanu, Dumitru; Tas, Aysegul; MatematikTwo different approaches continuous wavelet transform (CWT) and artificial neural network (ANN) were successfully applied to the quantitative resolution of ternary mixtures of paracetamol (PAR), metamizol (MET) and caffeine (CA) having strongly overlapping spectra. First approach is based on the use of CWT signals of the ratio spectra of three active compounds in samples. Various CWT families were tested for the extraction of cardinal information and small noise condition and higher peaks of the original spectra. In this paper, three methods: Mexican hat function (MEX) (a = 70), reverse biorthogonal (RBIO3.5) (a = 100) and biorthogonal (BIOR2.4) (a = 90) were found suitable for determination of three active compounds and their signal analysis. ANN, as a multivariate numerical method, was used for the quantitative resolution of the same ternary mixtures. The performance of CWT and ANN approaches was validated by analyzing the synthetic mixtures of PAR, MET and CA compounds. In addition, the standard addition technique was also used for the same purpose. The experimental results provided by CWT technique were compared with each other and those obtained by ANN method and a coincidence was observed for all the obtained results.Article Citation - WoS: 7Citation - Scopus: 7Spectrophotometric Determination of Acetaminophen and Chlorzoxazone in Tablets by Multivariate Calibration Techniques(Chiminform Data S A, 2006) Dinc, Erdal; Baleanu, Dumitru; Ozdemir, Abdil; Onur, Feyyaz; Baleanu, Dumitru; Aksoy, Halil; Yuecesoy, Cem; Yücesoy, Cem; MatematikThree multivariate techniques, Inverse Least Squares (ILS), Principal Component Regression (PCR) and Partial Least Squares (PLS) were applied to the spectrophotometric determination of acetaminophen (AC) and chlorzoxazone (CL) in tablets without prior separation. Stock solutions of acetaminophen and chlorzoxazone were prepared in methanol. Standard solutions were obtained by dilution of stocks with 0.1 M HCl. The multivariate calibrations were built up using training set containing both drugs in different concentration ratios and measuring the absorbances at 14 wavelengths with 5-nm intervals over the wavelength-range of 210-310 nm. Chemometric calculations were performed with MATLAB 7.0 software, The proposed techniques were applied to a commercial formulation, which contains 300 mg AC and 250 mg a(n=10). The results were statistically compared with each other, as well as those obtained by the developed HPLC method.Article Citation - WoS: 22Citation - Scopus: 28Simultaneous Determination of Tartrazine and Allura Red in Commercial Preparation by Chemometric Hplc Method(Food & Drug Adminstration, 2006) Dinc, Erdal; Baleanu, Dumitru; Aktas, A. Hakan; Baleanu, Dumitru; Ustundag, Ozgur; MatematikThe concentrations of tartrazine (TAR) and allura red (ALL) in binary mixtures and commercial preparation were determined by the combined use of chemometric (or multivariate) calibrations and HPLC method. In this study, partial least squares (PLS), principal component regression (PCR) and classical least squares (CLS) based on multiwavelength HPLC data were refined as multivariate calibration techniques such as CPLS, CPCR, CCLS. The relation between multiwavelength peak area data (x-block) and concentration set (y-block) were used to obtain the chromatographic multivariate calibrations. Multiwavelength-chromatograms or multiwavelength peak area data were obtained by using photodiode array (PDA) detectors. Waters Symmetry (R) C18 Column 5 mu m 4.6 x 250 mm and a combination of 0.2 M acetate buffer (pH = 5), acetonitrile, methanol and bidistilled water (55:20:10 v/v) at the flow rate of 1.9 mL/min were used to obtain a good chromatographic separation between TAR and ALL in presence of sunset yellow (Internal Standard (IS)). These chromatographic multivariate techniques were validated by analyzing the different synthetic mixtures and by using standard addition technique. These methods were applied to the commercial soft drinking powder samples containing TAR and ALL. The results from these chromatographic multivariate techniques were compared with each other as well as obtained by alternative single HPLC method.Article Citation - WoS: 5Citation - Scopus: 9Combined Application of Continuous Wavelet Transform-Zero Crossing Technique in the Simultaneous Spectrophotometric Determination of Perindopril and Indapamid in Tablets(Soc Brasileira Quimica, 2009) Pektas, Goezde; Baleanu, Dumitru; Dinc, Erdal; Baleanu, Dumitru; Pektag, Gözde; MatematikSignal processing methods based on the combined use of the continuous wavelet transform (CWT) and zero-crossing technique were applied to the simultaneous spectrophotometric determination of perindopril (PER) and indapamide (IND) in tablets. These signal processing methods do not require any priory separation step. Initially, various wavelet families were tested to identify the optimum signal processing giving the best recovery results. From this procedure, the Haar and Biorthogonal 1.5 continuous wavelet transform (HAAR-CWT and BIOR 1.5-CWT, respectively) were found suitable for the analysis of the related compounds. After transformation of the absorbance vectors by using HAAR-CWT and BIOR 1.5-CWT, the CWT-coefficients were drawn as a graph versus wavelength and then the HAAR-CWT and BIOR 1.5-CWT spectra were obtained. Calibration graphs for PER and IND were obtained by measuring the CWT amplitudes at 231.1 and 291.0 rim in the HAAR-CWT spectra and at 228.5 and 246.8 nm in BIOR 1.5-CWT spectra. respectively. In order to compare the performance of HAAR-CWT and BIOR 1.5-CWT approaches, derivative spectrophotometric (DS) method and HPLC as comparison methods, were applied to the PER-IND samples. In this DS method, first derivative absorbance values at 221.6 for PER and 282.7 nm for IND were used to obtain the calibration graphs. The validation of the CWT and DS signal processing methods was carried out by using the recovery study and standard addition technique. In the following step, these methods were Successfully applied to the commercial tablets containing PER and IND compounds and good accuracy and precision were reported for the experimental results obtained by all proposed signal processing methods.