Cefquinome sulfate

Spectral resolution of cefquinome sulfate (CFQ) in the presence of its degradation products was studied. Three selective, accurate and rapid spectrophotometric methods were performed for the determination of CFQ in the presence of either its hydrolytic, oxidative or photo-degradation products. The proposed ratio difference, derivative ratio and mean centering are ratio manipulating spectrophotometric methods that were satisfactorily applied for selective determination of CFQ within linear range of 5.0-40.0 μg mL(-1). Concentration Residuals Augmented Classical Least Squares was applied and evaluated for the determination of the cited drug in the presence of its all degradation products. Traditional Partial Least Squares regression was also applied and benchmarked against the proposed advanced multivariate calibration. Experimentally designed 25 synthetic mixtures of three factors at five levels were used to calibrate and validate the multivariate models.

Maintenance of adequate drug concentration at the site of infection is an important problem in mastitis antibiotic therapy, and the efficacy of intramammary β-lactams can be optimized by maintaining the drug concentration at the site of infection above the minimum inhibitory concentration (MIC) as long as possible. The most important pharmacokinetic and pharmacodynamic parameter for efficacy evaluation is time during which drug concentrations exceed the MIC (t>MIC). In this study, we assessed the pharmacokinetic profile of cefquinome (CFQ) after repeated intramammary administration in healthy cows and cows subclinically infected with Staphylococcus aureus as well as the MIC of Staph. aureus field strains. In addition, the degree of drug passage was investigated from udder to bloodstream by measuring systemic drug absorption in healthy and infected animals. Cefquinome concentrations were quantified by HPLC (UV-visible detection) in milk samples collected from quarters and from blood serum samples.

A novel and sensitive stability-indicating RP-HPLC method for the quantitative determination of cefquinome sulfate has been developed. Chromatographic separation and quantitative determination were performed using a high-performance liquid chromatograph with UV detection. As the stationary phase a LiChroCART RP-18 column (5 microm particle size, 125 mm x 4 mm, Merck, Darmstadt, Germany) was used. The mobile phase consisted of 10 volumes of acetonitrile and 90 volumes of an 0.02 M phosphate buffer (pH = 7.0). The flow rate of the mobile phase was 1.0 mL/min. The eluents were monitored by a UV-VIS detector at 268 nm. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Significant degradation was found under basic, oxidizing stress and UV light. The developed method was validated with respect to linearity, accuracy, precision and robustness.

Two novel cefquinome sulfate (CFQ)-selective electrodes were performed with dibutyl sebacate as a plasticizer using a polymeric matrix of polyvinyl chloride. Sensor 1 was prepared using sodium tetraphenylborate as a cation exchanger without incorporation of ionophore, whereas 2-hydroxy propyl β-cyclodextrin was used as ionophore in sensor 2. A stable, reliable, and linear response was obtained in concentration ranges 3.2 × 10(-5) to 1 × 10(-2) mol/L and 1 × 10(-5) to 1 × 10(-2) mol/L for sensors 1 and 2, respectively. Both sensors could be sufficiently applied for quantitative determination of CFQ in the presence of degradation products either in bulk powder or in pharmaceutical formulations. Sensor 2 provided better selectivity and sensitivity, wider linearity range, and higher performance. Therefore it was used successfully for accurate determination of CFQ in biological fluids such as spiked plasma and milk samples. Furthermore, an online kinetic study was applied to the CFQ alkaline degradation process to estimate the reaction rate and half-life with feasible real-time monitoring.