Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article Citation - WoS: 19Citation - Scopus: 18A New Application of Chemometric Techniques To Hplc Data for the Simultaneous Analysis of a Two-Component Mixture(Taylor & Francis inc, 2005) Üstündag, Ö; Özdemir, A; Baleanu, D; Dinç, EA new chemometric approach using high performance liquid chromatography (HPLC) with photodiode array (PDA) detection was developed and applied to the simultaneous determination of enalapril maleate (EA) and hydrochlorothiazide (HCT) in tablets. Chernometric calibration techniques, classical least squares (CLS), principle component regression (PCR), and partial least squares (PLS) were subjected to the peak area at multiwavelength PDA detector responses. The combination of HPLC and chernometric calibration techniques was called HPLC-CLS, HPLC-PCR, and HPLC-PLS. For comparison purposes, the HPLC method called classical HPLC method was used for the confirmation of the results obtained from combined HPLC-chemometric calibration techniques. A good chromatographic separation between two drugs and internal standard (IS) was achieved using a Waters Symmetry (R) C 18 Column 5 mu m 4.6 x 250 mm and a mobile phase consisting of 0.2M acetate buffer and acetonitrile (v/v, 60:40). The multiwavelength PDA detection was done at 230 (A), 240 (B), 250 (C), 250 (D), 240 (E) nm wavelengths, and peak area was recorded for the concentration set in the mobile phase. Three HPLC-chemometric calibrations and a classical-HPLC method were tested by analyzing the synthetic mixture of EA and HCT in the presence of losartan potassium (IS). The proposed methods were applied to real samples containing the present two drugs. The obtained results were statistically compared with each other.Article Citation - WoS: 20Citation - Scopus: 22Simultaneous Spectrophotometric Analysis of Codeine Phosphate, Acetylsalicylic Acid, and Caffeine in Tablets by Inverse Least-Squares and Principal Component Regression Techniques(Taylor & Francis inc, 2002) Baleanu, D; Onur, F; Dinç, EInverse least-squares (ILS) and principal component regression (PCR) techniques were proposed for the spectrophotometric simultaneous analysis of ternary mixture containing codeine phosphate, acetylsalicylic acid and caffeine without any pretreatment. A training set of the title drugs was randomly prepared for both techniques. The absorbance values were measured at the 15 points in the wavelength range 220-290 nm for the absorption spectra. The ILS and PCR calibrations were constructed by using their algorithms and they were tested for the synthetic mixtures of three drugs. Means recoveries and relative standard deviations for ILS and PCR were found as 100.2 and 1.23%, 99.5 and 2.10% for codeine phosphate, 100.5 and 1.30%, 100.3 and 1.18% for acetylsalicylic acid and 99.4 and 1.33%, 99.3 and 1.31% for caffeine, respectively. We realised the numerical computations by using the 'Maple V' software. The results were successfully observed by applying the chemometric techniques to the tablets, and a good agreement was found between the obtained values and the indicated quantities of the pharmaceutical formulation marketed in Turkey.Article Citation - WoS: 54Citation - Scopus: 59An Approach To Quantitative Two-Component Analysis of a Mixture Containing Hydrochlorothiazide and Spironolactone in Tablets by One-Dimensional Continuous Daubechies and Biorthogonal Wavelet Analysis of Uv-Spectra(Taylor & Francis inc, 2003) Baleanu, D; Üstündag, Ö; Dinç, EIn this study a new method of quantitative two-component analysis of a mixture of hydrochlorothiazide (HCT) and spironolactone (SP) in the presence of strongly overlapping signals was achieved by using one-dimensional continuous wavelet analysis. This new method was built on the simultaneous use of both continuous wavelet transform and the zero crossing technique for the quantitative resolution of this binary mixture. A series of solutions, in the concentration range of 2-22 mg/ml for both compounds, in methanol and 0.2 M sodium acetate buffer, pH = 5 (20:80), were considered. The absorption spectra of the standard solutions were recorded in the wavelength range of 215-330 nm. To apply our methods we selected 400 points from the absorption spectra and we subjected the corresponding signal to Daubechies2 (DAUB2) and Biorthogonal1.5 (BIOR1.5) one-dimensional wavelet transform. In the transformed signals, the amplitude of HCT was measured at the position of a zero crossing point of SP and vice versa. Thus simple linear regression analysis can be applied to establish calibrations for both components. These calibrations were validated with synthetic mixtures of HCT and SP. MATLAB 6.5 software was used for one-dimensional wavelet analysis, and the basic concepts about wavelet method are briefly explained. The method developed in this paper is rapid, easy to apply, inexpensive and it is suitable for analysis of the overlapping signals of compounds in their mixtures without any chemical pre-treatment.Article Citation - WoS: 24Citation - Scopus: 28Chemometric Approach To Simultaneous Chromatographic Determination of Paracetamol and Chlorzoxazone in Tablets and Spiked Human Plasma(Taylor & Francis inc, 2006) Ozdemir, A; Aksoy, H; Baleanu, D; Dinç, ENew chemometric approaches were introduced into the high performance liquid chromatographic (HPLC) determination of chlorzoxazone (CZX) and paracetamol (PAR) in the tablets and spiked human plasma. These chemometric approaches contain the application of classical least squares (CLS), principle component regression (PCR), and partial least squares (PLS) calibrations to the multiwavelength HPLC peak area obtained by plotting the chromatograms at the five wavelengths. The multichromatograms were obtained by using the photodiode array detector at 225 (A), 240 (B), 255 (C), 270 (D), and 285 (E) nm. The algorithms of CLS, PCR, and PLS were applied to the multichromatogram data to construct the HPLC-CLS, HPLC-PCR, and HPLC-PLS calibrations. A mixture of acetonitrile and 0.1 M ammonium carbonate (60:40, v/v) on a Waters Symmetry (R) trademark C18 Column 5 mu m 4.6 x 250 mm at a flow rate of 0.8 mL/min was used as a mobile phase to separate and determine CZX and PAR in samples. Hydrochlorothiazide (IS) was used as an internal standard in this chromatographic separation. The HPLC chemometric calibrations were successfully applied to the quantitative analysis of the investigated drugs in commercial pharmaceutical preparation and spiked human plasma samples with high precision and accuracy.