Capillary Electrophoretic Method For Determination Research Articles

Development of a capillary electrophoretic method for determination of ketorolac enantiomers in human plasma using cationic β-cyclodextrin derivative as a chiral selector.

A novel approach for the separation of ketorolac enantiomers by capillary electrophoresis is presented. A cationic β-cyclodextrin derivative based on imidazole was synthesized and used as a chiral selector in the background electrolyte. The influence of pH and ionic strength of background electrolyte, as well as cationic β-cyclodextrin derivative concentration on the resolution of ketorolac enantiomers, was investigated. The highest value of the resolution for ketorolac enantiomers was 1.46 when the background electrolyte consisted of 25mM NaH2 PO4 (pH 6.4) with 1mM 1-butyl-3-β-cyclodextrinimidazolium tosylate. Additionally, the possibilities of cationic derivatives for the separation of ketoprofen enantiomers were shown (peak resolution 1.06). The two-step preconcentration mode was developed to reduce the limit of detection of individual enantiomers. The proposed approach was successfully applied to determine ketorolac enantiomers in tablet "Ketorol express" and human plasma. The calibration range of ketorolac enantiomers for plasma samples was 0.25-2.50μg/ml with coefficients of determination ≥ 0.99. The relative standard deviation both of the peak area and migration time was less than 15%, as well as the accuracy ranged from 90.1% to 110.2% for both analytes. The limits of detection were 44 and 55ng/ml for R- and S-ketorolac. The quantity of ketorolac in plasma was verified with high-performance liquid chromatography.

Development and Validation of a Green Capillary Electrophoretic Method for Determination of Polyphenolic Compounds in Red Wine Samples

A sensitive, simple, rapid, experimentally convenient, cost-effective, environmentally friendly and high-throughput green chemistry by capillary electrophoresis (CE) approach for the determination of eight polyphenolics frequently found in red wines from USA was carried without using toxic organic modifier. Several parameters which affect the separation were investigated to determine the optimum conditions. At room temperature, the eight polyphenolics could be well separated within 15 min in a 55-cm length capillary at a separation voltage of 26 kV with 40-mM borate buffer (pH 8.9). The method was fully validated showing satisfactory data for all method validation parameters tested. The limits of detection varied from 0.15 to 0.32 µM. The relative standard deviations of migration varied from 0.208 to 0.630 %. The Californian red wine samples analyzed were bought in the local markets, and the polyphenolic compound recoveries were in the range of 98–99.7 %. The method was successfully applied to the determination of the studied polyphenolics in red wine samples with satisfactory recoveries. Catechin, syringic acid, apigenin, myricetin, luteolin, quercetin, caffeic acid, and gallic acid were detected in all samples, with gallic acid and myricetin occurring in the highest concentration.

Field-amplified sample stacking–sweeping of vitamins B determination in capillary electrophoresis

A capillary electrophoretic method for determination of five water soluble vitamins B along with baclofen as an internal standard has been developed and assessed in context of precision, accuracy, sensitivity, freedom from interference, linearity, detection and quantification limits. On-line preconcentration technique, namely field-amplified sample stacking (FASS)–sweeping, has been employed in respect to obtain more sensitive analysis. Separation conditions received after optimization procedure were as following background electrolyte (BGE), 10mM NaH2PO4, 80mM SDS, (pH 7.25); sample matrix (SM), 10mM NaH2PO4 (pH 4.60); uncoated fused silica capillary (50μm i.d.×67cm length); UV spectrophotometric detection at 200nm; injection times: 10s and 30s at 3.45kPa; applied voltage 22kV; temperature 22°C. Validation parameters, namely precision, accuracy and linearity, were considered as satisfactory. Under the optimized conditions, it has been also successfully applied for vitamins B determination in bacterial growth medium and commercially available Ilex paraguariensis leaves.

Simultaneous Determination of Five Benzimidazoles in Feeds Using High-Performance Capillary Electrophoresis

A high-performance capillary electrophoretic method for determination of five benzimidazoles (thiabendazole, albendazole, fenbendazole, mebendazole, oxfendazole) in animal feeds was developed. Separation was carried out in an 80.5 cm x 75 microm id fused-silica uncoated capillary and injected by hydrodynamic injection (35 mbar x 8 s) at a wavelength detection of 295 nm. The drugs were completely resolved in 50 mmol/L citric acid buffer (pH 1.9) with 30 kV at a temperature of 25 degrees C. Linear range was 1-80 microg/mL; limits of detection for the analytes were less than 2 mg/kg; the overall recoveries for benzimidazoles were >73%, with coefficients of variation below 10%.

Capillary electrophoresis determination of thiopurine methyl transferase activity in erythrocytes

Thiopurine S-methyltransferase (TPMT) catalyzes methylation of thiopurine drugs (e.g. 6-mercaptopurine, azathioprine). Decreased activity of TPMT is associated with hematopoietic toxicity after administration of standard doses of the drugs. We developed capillary electrophoretic method for determination of TPMT enzyme activity in erythrocytes. Limit of quantification of the method is 1.5 μmol/L (S/N = 6). The recovery of 6-methylmercaptopurine was 87.5–94.8%, imprecision value (as CV, n = 10) was 1.68% (within-day) and 2.53% (between-day). Erythrocyte TPMT activities were measured in 60 healthy adult volunteers.

Capillary Electrophoretic Method for Determination of Matrine in Caco‐2 Cell Medium

A capillary electrophoretic (CE) method has been developed for the analysis of matrine in a biological medium. The optimized run buffer solution contained 200 mM tris(hydroxymethyl)aminomethane, 40 mM sodium dihydrogen phosphate, and 20% 2‐propanol, adjusted to pH 5.8 using phosphoric acid. A voltage of 25 kV was applied across a capillary (50 µm × 40 cm, distance to detector: 10.2 cm) for CE separation. Each analysis was completed in less than 5 min. Linearity of matrine calibration in the concentration range of 3.2–185 µg/mL (at the detection wavelength of 214 nm) was excellent (R 2 = 0.9994). The run‐to‐run repeatability (n = 3), as expressed by the relative standard deviation (RSD), was found to be better than 4.0%. The limit of detection was estimated to be 3.2 µg/mL. This CE method was employed to determine matrine in Caco‐2 cell media after transport of matrine through the cells.

Capillary electrophoretic method for determination of protease inhibitor indinavir sulfate used in human immunodeficiency virus therapy

A simple, fast and reliable capillary electrophoresis (CE) method for determination of indinavir sulfate, a potent protease inhibitor used in human immunodeficiency virus (HIV) therapy, in commercial and simulated capsule formulations is described. The analysis was performed in a 75 μm i.d. uncoated fused-silica capillary with 27 cm length (effective length of 19.4 cm) using a 20 mmol l −1 phosphate buffer at pH 2.52. Samples were injected hydrodynamically by applying 0.5 psi pressure during 2 s. The applied voltage was 28 kV. Direct UV detection at 214 nm led to an adequate sensitivity without interference from sample excipients and known impurities. For quantitative purposes, diazepam was used as internal standard. Under optimized conditions, the migration times for indinavir sulfate and diazepam were 1.06 and 1.66 min, respectively. Analytical curve of peak area ratios versus concentration in the range of 20.0–100.0 μg/ml gave a coefficient of correlation of 0.9992, establishing the method linearity. The limits of detection and quantitation were 4.61 and 14.0 μg/ml, respectively. The within-day precision expressed as relative standard deviation was <1.5% for 10 consecutive sample injections. An average recovery of 100.81±0.56% at three concentration levels was obtained. Based on the performance characteristics, the proposed methodology was found suitable for the determination of indinavir sulfate in capsule formulations, presenting additional advantages inherent to the CE technology, such as low consumption of reagents and column endurance.

Application of micellar electrokinetic chromatography to the determination of sultamicillin in oral pharmaceutical preparations.

A micellar electrokinetic capillary electrophoretic method for determination of sultamicillin in Unasyn oral preparations--tablets and suspension--was evaluated. Phosphate-borate buffer at pH 7.0 containing 1.0% sodium dodecylsulfate was used as a mobile phase. The elaborated method ensures separation of sultamicillin from p-toluenesulfonic acid and the impurities, ampicillin, sulbactam and penicillamine. The method was validated for specificity, reproducibility, precision, accuracy and assay linearity (in a concentration range of sultamicillin of 0.05-1.5 mg/ml). Statistical analysis by Student's t-test showed no significant differences between the results obtained by micellar electrokinetic chromatography and HPLC, t(calculated) 0.519 for suspension assays and 0.284 for tablets assays were smaller then t(tabulated).