Electrochemical analysis of cephalosporin antibiotics

Development and Validation of a Simple Procedure for the Kinetic Spectrophotometric Quantitative Determination of Ceftriaxone Using Potassium Caroate

A simple procedure for the quantitative determination of the Ceftriaxone pure substance by the spectrophotometric method in its kinetic modification using Caro’s acid has been developed and validated. The scheme of the chemical transformation of Ceftriaxone with the reaction of potassium caroate has been proposed. The appearance of a new wave gives the possibility of developing a new procedure for the quantitative determination of Ceftriaxone. The obtained results of accuracy and precision are as follows: RSD = 1.63-2.25 %, δ = 0.33-0.96 %. LOD = 0.1 µg/mL, LOQ = 0.33 µg/mL.

Adsorptive cathodic stripping voltammetric determination of cefoperazone in bulk powder, pharmaceutical dosage forms, and human urine

The electroreduction behaviour and determination of cefoperazone using a hanging mercury drop electrode were investigated. Cyclic voltammograms of cefoperazone recorded in universal Britton-Robinson buffers pH 3-6 exhibited a single irreversible cathodic peak. The process was adsorption-controlled. Britton-Robinson buffer 0.04 M pH 4.0 was selected as a supporting electrolyte for quantitative purposes by differential pulse and square wave adsorptive cathodic stripping voltammetry. The experimental voltammetric conditions were optimized using Central Composite Face design. A reduction wave was seen in the range from -0.7 to -0.8 V. These voltammetric techniques were successfully validated as per ICH guidelines and applied for the determination of cefoperazone in its single and sulbactam containing powders for injection and statistically comparable to USP-HPLC. They were further extended to determine cefoperazone in spiked human urine with no matrix effect.

Determination of cefonicid in human urine by adsorptive square-wave stripping voltammetry

The adsorption behavior of cefonicid on the hanging mercury drop electrode (HMDE) has been examined using cyclic voltammetry and square-wave voltammetry techniques in Britton-Robinson (B-R) buffers in the pH range of 2.0-11.0. The effect of different parameters on the accumulation behavior of the adsorbed species has been evaluated. Sensitive measurements can be achieved after controlled adsorption on the surface of HMDE followed by square-wave voltammetry. Under optimal conditions, a detection limit of 4.0 x 10(-8) M and a linear calibration graph in the range 1.0 x 10(-7)-1.0 x 10(-6) M were obtained. Direct simple determination of cefonicid in urine was established with no manipulation of urine sample other than dilution and subsequent adsorptive stripping voltammetric determination. The detection limit of the method was 1.0 microg x ml(-1) of cefonicid in urine.

LC determination of cephalosporins in in vitro rat intestinal sac absorption model

Cefotaxime sodium (CX) and Ceftazidime pentahydrate (CZ) are peptidomimetic cephalosporins (CPS) which exist as zwitterionic compounds at physiological pH and because of this reason they are not absorbed appreciably on peroral administration. The permeability of these compounds can be increased transiently by altering membrane characteristics of absorptive epithelium by use of sorption promoters (SPs). In present work a simple validated HPLC method utilizing isocratic mobile phase and having short retention times for CX and CZ is developed which can be used to monitor their concentrations in Kreb's Ringer Bicarbonate (KRB) solution in in vitro intestinal sac absorption model. The same was utilized to determine apparent permeability coefficients and absorption profiles of CPS by modified Wilson-Wiseman method. The CPS were analysed by the reverse phase HPLC method using Shim-pack C18 column. The mobile phase used was of isocratic composition with phosphate buffer (pH 7.0, 3.5 g/l of KH(2)PO(4) dissolved in 0.03 M Na(2)HPO(4).2H(2)O) and methanol in proportion 85:15 for CZ and 70:30 for CX. The flow rate was 1 ml/min and quantitative determinations were carried out at 254 nm at 25 degrees C. The method was found specific because none of the proposed SPs, components of KRB and intestinal sac artefacts interfered with the drug peaks. The drug concentration versus area under peak relationship was found to be linear in concentration range of 0.25-20.0 microg/ml. The recovery studies, intraday variation, interday variation and interanalyst variation were within statistical limits. The limit of detection (LOD) was 95.0 and 100.0 ng/ml for CZ and CX, respectively. The limit of Quantitation (LOQ) was 240.0 and 250.0 ng/ml for CZ and CX, respectively. The proposed method was found to be rapid and selective and hence applied for continuous monitoring of CPS in in vitro intestinal sac absorption studies.

Study on electrooxidation of cefadroxil monohydrate and its determination by differential pulse voltammetry

In this work electrooxidation of cefadroxil monohydrate was investigated using a glassy carbon electrode depending on pH and supporting electrolyte. It was shown that the direct determination of the substance from capsules and in oral suspension could be made by differential pulse voltammetry (DPV). UV and first derivative UV spectrophotometric methods are also proposed as comparative methods.

Electrochemical study of cefetamet-Na and its polarographic determination

Polarographic behavior of cephalosporin cefetamet-Na (Cef-Na) in aqueous solutions of pH ranging from 1.7 to 12.5 was investigated by applying direct current (dc) polarography, differential pulse polarography (dpp), alternating current (ac) polarography, cyclic voltammetry and electrolysis at constant potential. The characteristics of the corresponding electrode reaction are presented and discussed. The electrode reaction was found to be affected by strong adsorption, strongly and slightly pronounced in acidic and alkaline media, respectively. The methoxyimino group electroreduction was carried out and the mechanistic scheme was suggested. In addition, a sensitive dpp method was proposed for analytical determination of a very low concentrations of Cef-Na.

Determination of ceftazidime in plasma using high-performance liquid chromatography and electrochemical detection. Application for individualizing dosage regimens in elderly patients

This study describes a sensitive HPLC-electrochemical detection method for the analysis of ceftazidime, a third-generation cephalosporin, in human plasma. The extraction procedure involved protein precipitation with 30% trichloroacetic acid. The separation was achieved on a reversed-phase column (250X4.6 mm I.D., 5 microm) packed with C18 Kromasil with isocratic elution and a mobile phase consisting of acetonitrile-25 mM KH2PO4-Na2HPO4 buffer, pH 7.4 (10:90, v/v). The proposed analytical method is selective, reproducible and reliable. The assay has a precision of 0.2-15.1% (C.V.) in the range of 5-200 microg mil(-1). (corresponding to 0.5 to 20 ng of ceftazidime injected onto the column), and is optimised for assaying 50 microl of plasma. The extraction recovery from plasma was approximately 100%. The method was highly specific for ceftazidime and there was no interference from either commonly administered drugs or endogenous compounds. This assay was used to measure ceftazidime in elderly patients for therapeutic drug monitoring.