Spectrophotometric Methods for the Determination of Acediasulfone in Mixture with Cinchocaine

Abstract

Derivative spectrophotometry techniques (ratio‐spectra first derivative and zero‐crossing first derivative) were described for simultaneous determination of acediasulfone and cinchocaine. Acediasulfone was also determined via the formation of a colored product as a result of its reaction with p‐dimethylaminobenzaldehyde. In the ratio‐spectra first derivative method, the measurements were taken at 310 and 233.9 nm for acediasulfone and cinchocaine, respectively. By the zero‐crossing first derivative method, lines of regression were taken at 318 and 233 nm for acediasulfone and cinchocaine, respectively. In the colorimetric method, absorbance measurements were obtained at 452 nm. Acediasulfone showed linearity over concentration ranges 2–14 µg/ml, 2–16 µg/ml, and 12–60 µg/ml for ratio‐spectra first derivative, zero‐crossing first derivative, and colorimetric methods, whereas cinchocaine showed linearity over concentration ranges 1–10 µg/ml and 2.28–16 µg/ml for ratio‐spectra first derivative and zero‐crossing first derivative techniques. The proposed methods proved to be specific and accurate for the analysis of the cited drugs in laboratory‐prepared mixtures and dosage form. The obtained results agree statistically with those obtained by reference methods.     

Development and Validation of HPLC,TLC and Derivative Spectrophotometric Methods for the Analysis of Ezetimibe in the Presence of Alkaline Induced Degradation Products

Reversed phase‐high performance liquid chromatography (RP‐HPLC), thin layer chromatography (TLC) densitometry and first derivative spectrophotometry (1D) techniques are developed and validated as a stability‐indicating assay of ezetimibe in the presence of alkaline induced degradation products. RP‐HPLC method involves an isocratic elution on a Phenomenex Luna 5μ C₁₈ column using acetonitrile: water: glacial acetic acid (50:50:0.1 v/v/v) as a mobile phase at a flow rate of 1.5 mL/min. and a UV detector at 235 nm. TLC densitometric method is based on the difference in Rf‐values between the intact drug and its degradation products on aluminum‐packed silica gel 60 F₂₅₄ TLC plates as stationary phase with isopropanol: ammonia 33% (9:1 v/v) as a developing mobile phase. On the fluorescent plates, the spots were located by fluorescence quenching and the densitometric analysis was carried out at 250 nm. Derivative spectrophotometry, the zero‐crossing method, ezetimibe was determined using first derivative at 261 nm in the presence of its degradation products. Calibration graphs of the three suggested methods are linear in the concentration ranges 1–10 mcg/mL, 0.1–1 mg/mL and 1–16 mcg/mL with a mean percentage accuracy of 99.05 ± 0.54%, 99.46 ± 0.63% and 99.24 ± 0.82% of bulk powder, respectively. The three proposed methods were successfully applied for the determination of ezetimibe in raw material and pharmaceutical dosage form; the results were statistically analyzed and compared with those obtained by the reported method. Validation parameters were determined for linearity, accuracy and precision; selectivity and robustness and were assessed by applying the standard addition technique.     

Rapid Determination of Metabolites in Bio‐fluid Samples by Raman Spectroscopy and Optimum Combinations of Chemometric Methods

The application of Raman spectroscopic techniques combined with multivariate chemometrics signal processing promise new means for the rapid multidimensional analysis of metabolites non‐destructively, with little or no sample preparation and little sensitivity to water. However, Rayleigh scattering, fluorescence and uncontrolled variance present substantial challenges for the accurate quantitative analysis of metabolites at physiological levels in biologically varying samples. Effective strategies include the application of chemometrics pretreatments for reducing Raman spectral interference. However, the arbitrary application of individual or combined pretreatment procedures can significantly alter the outcome of a measurement, thereby complicating spectral analysis. This paper evaluates and compares six signal pretreatment methods for correcting the baseline variances, together with three variable selection methods for eliminating uninformative variables, all within the context of multivariate calibration models based on partial least squares (PLS) regression. Raman spectra of 90 artificial bio‐fluid samples with eight urine metabolites at near‐physiological concentrations were used to test these models. The combination of multiplicative scatter correction (MSC), continuous wavelet transform (CWT), randomization test (RT) and PLS modeling presented the best performance for all the metabolites. The correlation coefficient (R) between predicted and prepared concentration reached as high as 0.96.     

Development and Validation of Derivative Spectrophotometric Method for Determination of Rabeprazole Sodium in Pharmaceutical Formulation

Abstract

The aim of this work is to develop and validate the derivative spectrophotometric method for determination of the proton pump inhibitor rabeprazole sodium in pharmaceutical formulations. The technique was applied using water (pH 10.0) as diluent. The first‐order derivative spectra were obtained at N=5, Δλ=4.0 nm, and determinations were made at 304 nm. The method showed high specificity in the presence of formulation excipients and good linearity in the concentration range of 6.0 to 18.0 µg/mL^?1. The intra‐ and interday precision data demonstrated the method has good reproducibility [Relative Standard Deviation ((RSD)=1.0 interdays)]. Accuracy was also evaluated and results were satisfactory (mean recovery of 99.15%). The detection and quantitation limits were 0.055 and 0.17 µg/mL^?1, respectively. The method was demonstrated to be adequate for routine analysis in quality control.     

Validated Stability-Indicating Chromatographic Methods for the Determination of Veralipride in Presence of Its Degradation Products

Two sensitive and selective chromatographic methods were developed and validated for determination of veralipride in presence of its degradation products. Forced degradation studies were performed, using HCl, NaOH and 3% H₂O₂. The first method is based on thin-layer chromatographic separation of the intact drug spot from its degradation, followed by densitometric measurements. The second method is based on isocratic liquid chromatographic separation of the studied drug from its degradation on a reversed phase C₁₈ column. The proposed LC method was utilized to investigate the kinetics of alkaline degradation process of the selected drug at different temperatures.     

Titrimetric and Spectrophotometric Methods for the Determination of Glyoxal and Analysis of Ternary Mixtures of Its Oxidation Products

Using thallium(III) as an oxidant, we developed titrimetric and spectrophotometric methods for the estimation of glyoxal at mmole and µmole levels, respectively. In the titrimetric method, thallium(I) formed is determined oxidimetrically with potassium bromate. In the spectrophotometric method, the absorbance of thallium(III) at 260 nm in the presence of 0.1 mol/L sodium chloride and 1.0 mol/L perchloric acid is measured. A plausible mechanism for the oxidation of glyoxal is proposed. Based on the selective oxidation of the probable oxidation products of glyoxal (namely, glyoxylic acid, formic acid, and oxalic acid), a convenient titrimetric method is described for analyzing ternary mixtures of these products.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 8, 2005, pp. 806–810.Original English Text Copyright © 2005 by Siva Rao, Prasada Rao.The text was submitted by the authors in English.     

血清白蛋白与巴比妥钠相互作用的光谱研究

采用荧光光谱、紫外-可见光谱研究了药物巴比妥钠(BBTS)和牛血清白蛋白(BSA)的相互作用机理,运用热力学方法确定了巴比妥钠和牛血清白蛋白相互作用力的类型主要是疏水力,该过程是一个熵增加、Gibbs自由能降低的自发超分子作用过程,根据Stern-Volmer方程和Lineweaver-Burk双倒数曲线方程求出了其结合常数在高温时比在低温时小,用F ster非辐射能量转移理论计算了二者结合时给体和受体之间的距离r=2.76 nm,能量转移效率E=0.332,证实了巴比妥钠和牛血清白蛋白之间的作用是生成复合物的静态猝灭过程,说明了猝灭机制是通过能量转移产生的。     

Employment of t-HPSAM in a Nonlinear Spectrophotometric System for Simultaneous Determination of Copper and Zinc

A procedure for the selection of wavelength pairs as part of the ternary H-point standard addition method (t-HPSAM) is presented. The t-HPSAM is employed for simultaneous determination of Cu(II) and Zn(II) using murexide as chromogenic reagent. The procedure is based on principal component analysis (PCA), and its advantage is the ability to isolate the analyte signal, even in the presence of apparent nonlinearity. In the present system, non-quantitative complex formation of one of the metal ions with ligand was the reason for nonlinear appearance. In our nonlinear system, selection of the most appropriate pair of variables became possible by means of proper rotation of score and loading plots from PCA. The reliability of the proposed procedure was evaluated using model data. The total relative standard error (RSE) for applying t-HPSAM (coupled with the proposed selection method) to 15 samples in the ranges of 0.00–40.00µM Cu(II) and 0.00–16.00µM Zn was 2.56% for Cu and 6.54% for Zn.     

Application of Multicriteria Methodology in the Development of Improved RP-LC-DAD for Determination of Rizatriptan and Its Degradation Products

The aim of this study was to establish an improved isocratic RP-LC-DAD method for separation and determination of rizatriptan benzoate and its two degradation products, L-749.019 and L-783.540 in tablets. Since the chromatographic behavior of target substances can be influenced by various experimental parameters, the whole study was carried out by employing experimental design methodology. The investigation included the influence of mutual changes of the mobile phase composition (methanol amount in the range 3–7% and pH of the water phase from 5.0 to 6.0) and the temperature (from 20 to 30 °C). The response surface design by means of Box-Brehnken design was used to obtain a predictive model which describes the changes in the response within the experimental domain. Additionally, several different target responses were evaluated and Derringer’s desirability function was used for reaching a suitable compromise among the responses. This multi-criteria decision making approach is based on constructing a desirability function for each individual response and afterwards establishing the overall desirability function. Such methodology provided us with the best operating conditions, satisfactory resolutions between the analytes and the shortest possible total analysis time. The experiments were performed on C₁₈ XTerra (150 mm × 3.9 mm), 5 μm column with the mobile phase consisting of a mixture of methanol, TEA and 0.01 mol L^?1 KH₂PO₄ (6:9.4:84.6 v/v) pumped at a flow rate of 1.2 mL min^?1, pH of the water phase adjusted to 6 with 85% orthophosphoric acid, a column temperature of 20 °C and detection at 225 nm. Afterwards, the new method was validated and subsequently applied in analysis of commercially available rizatriptan tablets.     

Fourier-Filtering Methods of Interference-Patterned Spectra in Multivariate Calibration and Prediction for Sample Identification and Thickness Determination

Summary: Determining the thickness or identification of polymer materials with building a multivariate calibration model is based on the near infrared spectral information of the material. The spectrum of a thin plastic sheet is modulated by the interference of multiply reflected beams from the boundary surfaces and causes a disturbing signal component. On one hand, this yields unidentifiable samples or introduces large errors in the sample prediction set. On the other hand, interference-patterned spectra have to be excluded from the calibration set. Fourier-transformation of an interference-patterned spectrum vs. wave number leads to a Fourier-spectrum as a function of the optical path length (OPL) containing a well recognizable interference peak. After replacing these interference-components and performing an inverse Fourier-transformation, the spectra can be used for calibration or prediction. Two types of replacing were studied: the spline-interpolation on Fourier- spectrum vs. OPL and a novel method based on linear approximation between Fourier-spectra and thickness values. The effectiveness of each filtering method was tested on low-density polyethylene and polypropylene sheets.     

Application of Multicriteria Methodology in the Development of Improved RP-LC-DAD for Determination of Rizatriptan and Its Degradation Products

A simple, rapid, and stability-indicating reversed-phase high-performance liquid chromatographic (LC) method for analysis for dutasteride has been successfully developed. Chromatography was performed on a 150 mm × 4.6 mm C₁₈ column with acetonitrile–water 60:40 (v/v) as isocratic mobile phase at 1.0 mL min⁻¹. Ultraviolet detection of dutasteride was at 210 nm. Its retention time was approximately 10 min and its peak was symmetrical. Response was a linear function of concentration over the range 0.2–1 μg mL⁻¹ (R ² = 0.997) and the limits of detection and quantitation were was 0.05 and 0.10 μg mL⁻¹, respectively. The method was validated for linearity, precision, repeatability, sensitivity, and selectivity. Selectivity was validated by subjecting dutasteride stock solution to photolytic, acidic, basic, oxidative, and thermal degradation. The peaks from the degradation products did not interfere with that from dutasteride. The method was used to quantify dutasteride in pharmaceutical preparations.

     

Innovative Spectrophotometric Methods for Determination of Almitrine Dismesylate and Raubasine in Duxil Tablets

Abstract

Ratio subtraction and isosbestic point are two methods used to determine a mixture of almitrine dismesylate and raubasine. Linear correlations were obtained in the range from 4 to 18 µg ml^?1 for almitrine dismesylate and 2 to 16 µg ml^?1 for raubasine, with mean accuracies 99.87 ± 1.053 for almitrine dismesylate and 99.75 ± 1.301 for raubasine. Almitrine dismesylate and raubasine (II) in their mixtures were analyzed by the two methods where the total content was determined at the isosbestic point at 214.0 nm and raubasine was determined by ratio subtraction. The proposed methods were validated to be suitable for analysis of the pharmaceuticals.     

Development and Validation of a High-Performance Liquid Chromatographic Determination of Ceftriaxone Sodium and Its Application to Drug Quality Control

Abstract

A reliable and sensitive RP-HPLC method was developed and validated for the quantitative estimation of ceftriaxone sodium (CFTZ) in pure drug and pharmaceutical dosage forms. The separation of ceftriaxone sodium was achieved on a Waters XTerra RP-18 (5 µm, 250 × 4.6 mm i.d.) column using photodiode array detector at 240 nm. The mobile phase consisted of 0.1 M triethylammoniumacetate–acetonitrile (60:40 v/v) mixture delivered at a flow rate of 1.0 ml/min. Accuracy, evaluated by means of the spike recovery method, was excellent, with percent recovery in the range 99.5–102% with precision in the range 0.3–1.2%.     

Development and Validation of Chromatographic Methods for the Quantification of Dabigatran Etexilate Mesylate in the Presence of Its Risky Degradation Products

JPC – Journal of Planar Chromatography – Modern TLC - New stability-indicating thin-layer chromatography (TLC)—densitometry and reversed-phase liquid chromatography (RP-LC)...     

Development and Validation of an HPLC Method for Determination of Ceftiofur Sodium

An isocratic high-performance liquid chromatographic method has been developed for assay of ceftiofur sodium in drug substance and in sterile powder for injection. Chromatography was performed on a 250 mm × 4.6 mm, 5 μm particle, C₁₈ column with a 78:22 (v/v) mixture of 0.02 m disodium hydrogen phosphate buffer (pH adjusted to 6.0 with 85% orthophosphoric acid) and acetonitrile as mobile phase, at a flow rate of 1.0 mL min⁻¹. The separation was monitored by UV detection at 292 nm. Validation of the method for linearity and range, intra- and inter-day precision, accuracy, specificity, recovery, robustness, and limits of quantification and detection yielded good results. The calibration plot was linear from 20.0–120.0 μg mL⁻¹ and the correlation coefficient was 0.9999. It was shown that ceftiofur was degraded under acidic, alkaline, oxidative, and photolytic conditions. The method was found to be stability-indicating and could be used for routine analysis of ceftiofur sodium for injection.     

Development and Validation of Selective Spectrophotometric Methods for the Determination of Pregabalin in Pharmaceutical Preparation

Three simple, quick and sensitive methods are described for the spectrophotometric determination of pregabalin (Pgb) in pharmaceutical preparations. Among them, the first two methods are based on the reaction of Pgb as n-electron donors with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π-acceptors to give highly colored complex species. The colored products were quantitated spectrophotometrically at 494 and 841 nm for DDQ and TCNQ, respectively. Optimization of the different experimental conditions was conducted. Beer’s law was obeyed in the concentration ranges 2.0—30.0 and 1.5—10 µg•mL－1 for DDQ and TCNQ methods, respectively. The third method is based on the interaction of ninhydrin (NN) with primary amine present in the pregabaline. This reaction produces a blue coloured product in N,N-dimethylformamide (DMF) medium, which absorbs maximally at 573 nm. Beer’s law was found in the concentration range 40.0—180.0 μg•mL－1. The methods were applied successfully to the determination of this drug in pharmaceutical dosage forms.     

Development and Validation of Spectrophotometric Methods for the Determination of Cefetamet in Pharmaceutical Dosage Forms

Two simple and sensitive spectrophotometric methods for the determination of cefetamet in either pure form or in its pharmaceutical formulations were described. The method Ⅰ is based on the interaction of 3-methylbenzo[d]- thiazolin-2-one hydrazone （MBTH） with cefetamet in the presence of freshly prepared ferric chloride in a neutral medium. The resulting blue colored product has λmax at 628 nm. The method Ⅱ describes the reduction of ferric ion by the drug to ferrous ion followed by a complex formation reaction with 1,10-phenanthroline （1,10-phen） to form an orange red colored chromogen exhibiting 2max at 510 nm. The products are stable for more than 5 and 8 h respectively. Common excipients used as additives in pharmaceutical preparations do not interfere in the proposed methods. Both methods are highly reproducible and have been applied to a wide variety of pharmaceutical preparations and the results are comparable with those of official methods.     

血清中肌酐的检测方法及其进展

描述了肌酐的检测在涉及临床诊断研究方面的重要意义,肌酐常用的检测方法有Jaffé反应法、酶法、毛细管电泳法、高效液相色谱法、拉曼散射法、同位素稀释质谱法等。目前没有肌酐检测方法的系统总结,本文较全面地综述了肌酐常用的检测方法及进展。     

Development and Validation of Different Spectrophotometric and High-Performance Thin-Layer Chromatographic Methods for the Determination of Fosinopril Sodium,Hydrochlorothiazide, and Chlorothiazide as Hydrochlorothiazide Impurity

JPC – Journal of Planar Chromatography – Modern TLC - Three simple, sensitive, and validated methods were developed for the quantitative determination of fosinopril sodium (FOS) and...