Determination of captopril in pharmaceutical preparation and biological fluids using two- and three-way chemometrics methods

Spectrophotometric method has been developed for the direct quantitative determination of captopril in pharmaceuticalpreparation and biological fluids(human plasma and urine)samples.The method was accomplished based on parallel factoranalysis(PARAFAC)and partial least squares(PLS).The study was carried out in the pH range from 2.0 to 12.8 and with aconcentration from 0.70 to 61.50 μg mL~(-1)of captopril.Multivariate calibration models such as PLS at various pH and PARAFACwere elaborated from ultraviolet spectra deconvolution and captopril determination.The best models for this system were obtainedwith PARAFAC and PLS at pH 2.0.The applications of the method for determination of real samples were evaluated by analysis ofcaptopril in pharmaceutical preparations and biological fluids with satisfactory results.The accuracy of the method,evaluatedthrough the RMSEP,was 0.5801 for captopril with best calibration curve by PARAFAC and 0.6168 for captopril with PLS at pH 2.0model.     

偏最小二乘法及主组分回归法用于药物组分的测定

本文研究了多元校准方法——偏最小二乘法(PLS)和主组份回归法(PCR)在药物多组份光度分析中的应用,获得了较满意的结果。而且在系列校准样品的实验设计、交叉证实法确定最佳因子数以及空缺组份体系的分析等方面进行了探讨。     

Validated spectrophotometric method for quantitative determination of simvastatin in pharmaceutical formulations and human serum

A simple ultraviolet spectrophotometric method for the determination of simvastatin in methanol has been devised and compared with the existing pharmacopoeial RP-HPLC method for the estimation of the drug. Analytical parameters such as stability, selectivity, accuracy, and precision have been established for the method, using SIMS® tablets and human serum samples, and evaluated statistically to assess the application of the method. The method was validated under ICH and USP guidelines and was found to comprise the advantages for simplicity, stability, sensitivity, reproducibility, and accuracy for use as an alternative to existing nonspectrophotometric methods for the routine determination of the drug in pharmaceutical formulations and for pharmaceutical investigations involving simvastatin.     

Simultaneous Spectrofluorimetric Determination of Paracetamol and Caffeine in Pharmaceutical Preparations in Solid‐Phase Using Partial Least Squares Multivariate Calibration

Abstract

Partial least‐squares algorithm (PLS)‐1 was used for the solid‐phase spectrofluorimetric determination of paracetamol (PA) and caffeine (CF) in pharmaceutical formulations. In despite of the closely overlapping spectral bands, the method allows the simultaneous quantification and sample preparation prior to analysis is not required. The calibration set consisted of 96 samples with 100–400 mg/g^?1 PA plus 10–65 mg/g^?1 CF; another set of 25 samples was used for external validation. Agreement between predicted and experimental concentrations was fair (r=0.993 and 0.964 for PA and CF models). Prediction performance was evaluated in terms of the coefficient of variability (CV), relative predictive determination (RPD), and ratio error range (RER). The PLS‐1 model was used for the determination of PA and CF in pharmaceutical formulations.     

Solid-phase spectrofluorimetric determination of acetylsalicylic acid and caffeine in pharmaceutical preparations using partial least-squares multivariate calibration

PLS-1, a variant of the partial least-squares algorithm was used for the solid-phase spectrofluorimetric determination of acetylsalicylic acid (ASA) and caffeine (CF) in pharmaceutical formulations. The method allows the simultaneous quantification of the analytes, as the closely overlapping spectral bands are efficiently solved. Sample preparation prior to analysis is not required. The calibration set consisted of 83 samples with 50-170 mg g⁻¹ ASA plus 5-20 mg g⁻¹ CF; another set of 25 samples was used for external validation. Agreement between predicted and experimental concentrations was fair (r = 0.987 and 0.974 for ASA and CF models). For both models, the prediction performance was evaluated in terms of the coefficient of variability (CV), relative predictive determination (RPD), and ratio error range (RER). The final PLS-1 models were used for the determination of ASA and CF in pharmaceutical formulations.     

Fluorometric determination of diphenhydramine by flow-injection analysis

A sensitive, rapid and simple flow injection procedure for the determination of diphenhydramine has been designed based on a fluorometric approach. An aqueous solution of diphenhydramine is injected into a carrierreagent stream containing Ce(IV) in dilute sulphuric acid and the fluorescence intensity of the Ce(III) produced is monitored. Chemical, FIA and instrumental variables were optimized. Analytical features of the method are: linear range 0.2–2 ppm, precision 0.7%, sample throughput 80/h. The influence of some foreign substances which can be found in typical pharmaceutical samples containing diphenhydramine was also investigated. The diphenhydramine content of a pharmaceutical preparation was determined.     

Comparison between micellar liquid chromatography and capillary zone electrophoresis for the determination of hydrophobic basic drugs in pharmaceutical preparations

The determination of highly hydrophobic basic compounds by means of conventional reversed-phase liquid chromatographic methods has several drawbacks. Owing to the characteristics of micellar liquid chromatography (MLC) and capillary electrophoresis (CE), these techniques could be advantageous alternatives to reversed-phase chromatographic methods for the determination of these kinds of compounds. The objective of this study was to develop and compare MLC and CE methods for the determination of antipsychotic basic drugs (amitryptiline, haloperidol, perphenazine and thioridazine) in pharmaceutical preparations. The chromatographic determination of the analytes was performed on a Kromasil C(18) analytical column; the mobile phase was 0.04 m cetyltrimethylammonium bromide (CTAB), at pH 3, containing 5% 1-butanol, at a flow rate of 1 mL/min. The CE separation was performed in a fused-silica capillary with a 50 mm tris-(hydroxymethyl)-aminomethane buffer, pH 7, at an applied voltage of 20 kV, using barbital as internal stardard. The proposed methods are suitable for a reliable quantitation of these compounds in the commercial tablets and drops in terms of accuracy and precision and require a very simple pre-treatment of the samples. By comparing the performance characteristics and experimental details of the MLC and CE methods we conclude that CE seems to be slightly better than MLC in the determination of highly hydrophobic compounds in pharmaceuticals in terms of resolution and economy, taking into account that the limits of detection are not a handicap in pharmaceutical samples.     

HPLC–based methods for the determination of levetiracetam in biological and pharmaceutical samples

Levetiracetam is one of the new generation anti–epileptic agents (also known as anticonvulsants or antiseizure drugs). Following its approval for marketing in 2000, levetiracetam has been widely used in the treatment of epilepsy due to its broad spectrum effects. One of the advantages of this antiseizure drug is its rapid and complete absorption after oral administration. It has also minimal drug–drug and food interactions, and shows more than 95% bioavailability. The determination of levetiracetam in various samples is carried out using several analytical methods including HPLC–based methods. HPLC–based methods are used for different pharmaceutical analyses and play an important role in drug monitoring during patient follow–ups. This review provides a summary of the HPLC–based methods used in the determination and quantification of levetiracetam in biological fluids and pharmaceutical preparations.     

Environmental and pharmaceutical analysis of dithiocarbamates

The current review aims at a comprehensive survey of analytical methods for the determination of dithiocarbamates (DTCs) in environmental and pharmaceutical samples. Besides parent compounds, analytical approaches for various metabolites and degradation products of DTCs are considered. Special emphasis is given to analyte stability as DTCs are considerably reactive interacting with various organic and inorganic compounds; in addition, depending on the chemical nature of the substance, DTCs are prone to oxidation and hydrolysis under alkaline and acidic conditions, respectively. The review mainly focuses on chromatography but also covers applications in electrophoresis, spectrophotometry, and biosensing.     

Determination of Vitamin B1 in Pharmaceutical Preparations by Flow-injection Analysis with Biamperometric Detection

IntroductionVitamin B1(VB1),also called thiamine,is animportant biomolecule,widely existing in beans,cere-al and meat,etc.So far,the application of spectropho-tometry[1,2],fluorimetry[3,4],high performance liquidchromatography[5],chemiluminescence[6]or potentiom-etry[7]for the determination of VB1has been reported.These methods have drawbacks,such as low selectivi-ty,elaborate procedures needed and a long responsetime.The dead-stop end-point biamperometry by usingtwo platinum foil electrodes…