基礎講座 電気泳動(Electrophoresis)

Statistics for analytical chemistry

A review of the identification and detection of heavy metal ions in the environment by voltammetry.

A review of the principles and application of modern electroanalytical techniques, namely, cyclic voltammetry, linear sweep voltammetry, differential pulse voltammetry, differential pulse polarography, square wave voltammetry, square wave polarography, stripping voltammetric, and stripping polarographic techniques, is presented. The use and advantages of these techniques at different electrodes are discussed. The analytical applications of these techniques to pharmaceutical compounds in dosage forms and biological media are also discussed. Various selected studies on these subjects since 1995 are reviewed.

Analysis of Pharmaceuticals and Biological Fluids Using Modern Electroanalytical Techniques

Rifampicin Inhibits α-Synuclein Fibrillation and Disaggregates Fibrils

A rapid, simple and highly sensitive second derivative synchronous fluorometric method has been developed for the simultaneous analysis of binary mixture of cinnarizine (CN) and domperidone (DOM). The method is based upon measurement of the native fluorescence of these drugs at Δλ = 80 nm in aqueous methanol (50% V/V). The different experimental parameters affecting the native fluorescence of the studied drugs were carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the range of 0.1 to 1.3 μg mL−1 and 0.1–3.0 μg mL−1 for CN and DOM, respectively with lower detection limits of 0.017 and 5.77 × 10−3 μg mL−1 and quantification limits of 0.058 and 0.02 μg mL−1 for CN and DOM. The proposed method was successfully applied for the determination of the studied compounds in synthetic mixtures and in commercial tablets. The results obtained were in good agreement with those obtained with reference methods. The high sensitivity attained by the synchronous fluorometric method allowed the determination of CN in real and spiked human plasma. The mean % recoveries in case of spiked human plasma (n = 3) were 96.39 ± 1.18 while that in real human plasma (n = 3) was 104.67 ± 4.16.

Second-derivative Synchronous Fluorometric Method for the Simultaneous Determination of Cinnarizine and Domperidone in Pharmaceutical Preparations. Application to Biological Fluids

A simple spectrophotometric method was developed for the determination of penicillamine and carbocisteine. The method depends on complexation of penicillamine with Ni, Co and Pb ions in acetate buffer pH of 6.3, 6.5 and 5.3, respectively, and carbocisteine with Cu and Ni ions in borate buffer pH of 6.7; 1-70 microg/ml of these drugs could be determined by measuring the absorbance of each complex at its specific lambdamax. The results obtained are in good agreement with those obtained using the official methods. The proposed method was successfully applied for the determination of these compounds in their dosage forms. Also, the molar ratio and stability constant of the metal complexes were calculated and a proposal of the reaction pathway was postulated.

Spectrophotometric determination of penicillamine and carbocisteine based on formation of metal complexes

A simple, stability indicating, reversed phase high performance liquid chromatographic method has been developed for the determination of nicardipine hydrochloride (NC) in the presence of its degradation products. Reversed phase chromatography was conducted using a Hibar‐C18 (150×4.6 mm i.d.) stainless steel column at ambient temperature with UV‐detection at 238 nm. Microemulsion mobile phase consisting of 0.175 M sodium dodecyl sulphate, 10% n‐propanol, 0.3% triethylamine in 0.02 M phosphoric acid of pH 6.5, has been used for the separation of nicardipine hydrochloride and its two degradation products at a flow rate of 1 mL min−1. The calibration curve was rectilinear over the concentration range 1‐40 µg mL−1 with a detection limit of 0.024 µg mL−1 (4.65×10−8 mol/L) and quantification limit of 0.08 µg mL−1 (1.55×10−7 mol/L). The proposed method was successfully applied for the analysis of nicardipine in pure form and commercial capsules, with the mean % recoveries of 100.12±0.28 and 100.87±0.41,...

Microemulsion Liquid Chromatographic Determination of Nicardipine Hydrochloride in Pharmaceutical Preparations and Biological Fluids. Application to Stability Studies

Two simple colorimetric methods for the determination of certain cephalosporins (cefaclor and cefadroxil) and amoxycillin sodium are described. The suggested methods depend upon the oxidation of these compounds using sodium hypochlorite (SHC) and 1-chlorobenzotriazole (1-CBT) in alkaline medium and colorimetric measurment of the chromophore formed. The different experimental parameters are studied and incorporated into the procedures. The mean percentages found range from 100.0 ± 0.4 to 100.5 ± 0.9. The proposed methods have been successfully applied to the analysis of some pharmaceutical formulations and the results obtained have been statistically compared with those obtaind using the official methods. The proposed methods are convenient, rapid within the concentration range 15-123 μg. ml−1.

Spectrophotometric Studies On Determination of Some Cephalosporins and Amoxycillin With Chlorobenzotriazole and Sodium Hypochlorite

Method development and validation for the simultaneous determination of cinnarizine and co-formulated drugs in pharmaceutical preparations by capillary electrophoresis.

M. I. Walash

Papers

Second-derivative Synchronous Fluorometric Method for the Simultaneous Determination of Cinnarizine and Domperidone in Pharmaceutical Preparations. Application to Biological Fluids

Spectrophotometric determination of penicillamine and carbocisteine based on formation of metal complexes

Microemulsion Liquid Chromatographic Determination of Nicardipine Hydrochloride in Pharmaceutical Preparations and Biological Fluids. Application to Stability Studies

Spectrophotometric Studies On Determination of Some Cephalosporins and Amoxycillin With Chlorobenzotriazole and Sodium Hypochlorite

Method development and validation for the simultaneous determination of cinnarizine and co-formulated drugs in pharmaceutical preparations by capillary electrophoresis.