Micellar electrokinetic chromatography for the determination of cortisol in urine samples in view of biomedical studies

An MEKC method used for the determination of cortisol in urine was developed and elaborated. In turn, the measurements of urinary free cortisol provided the diagnostic information for excess adrenal production of cortisol. MEKC realized by the addition of anionic surfactant SDS to the buffer solution was demonstrated to be the appropriate mode for the separation of cortisol and dexamethasone was used as internal standard. A buffer solution composed of 10 mM sodium tetraborate and 50 mM SDS at pH 8.8 was used. The MEKC assay was evaluated by analyzing a series of urine samples containing cortisol in variable concentrations. The proposed method was validated for specificity, linearity, LODs and LOQs, precision and trueness. The LOQ for cortisol equaled 5 ng/mL. The method was selective and reliable for identification and can detect changes of endogenous levels of cortisol in urine under different stress situations.

Optimization and validation of capillary electrophoretic method for the analysis of amphenicols in poultry tissues

A simple, rapid capillary electrophoretic (CE) method for simultaneous analysis of three amphenicols (chloramphenicol, thiamphenicol and florfenicol) in poultry tissues has been developed and validated. The separation condition were: buffer solution composed with 25 mM sodium tetraborate decahydrate and 10 mM sodium dodecylsulfate, an uncoated fused-silica capillary (57 cm x 75 microm i.d.), voltage 20 kV, and temperature 22 degrees C. The method involved simple deproteinization by acetonitrile and SPE extraction procedure. The analytical method was validated according to the FDA bioanalytical method guidance. The method was linear (r > 0.999) at concentrations ranging from: 0.005 - 1 for chloramphenicol, 0.01 - 1 for thiamphenicol, and 0.025 - 5 microg/g for florfenicol. The precision values were less than 9.8 for intra- and 14.8% for inter-day variability, and accuracies ranged from 92.0 to 106.0% for analyzed amphenicols. The overall recoveries of all antibiotics from tissue samples were above 82.2%. Some new parameters were calculated as limit of decision (CCalpha) and detection capability (CCbeta). The CE method is simple and reliable for simultaneous determination of residues of chloramphenicol, thiamphenicol and florfenicol in muscle with a total run time of less than 7 min.

Validated method forl-ornithine-l-aspartate analysis in human plasma by capillary electrophoresis

A rapid capillary electrophoresis method for routine determination of two amino acids, L-ornithine and L-aspartic acid, in human plasma is reported. The method runs automatically, requires a minimum of sample preparation and moreover includes no extensive extraction and no gradient or derivatization procedure. Analyses were performed on an uncoated silica capillary using buffer solution composed with 10 mM sodium tetraborate and 1 M sodium hydroxide (pH=10.0). A capillary electrophoresis P/ACE system equipped with UV detection (200 nm), an automatic injector, a fluid cooled cartridge and System Gold data station was used in this study. The total analysis time under these conditions was 8.0 min. The calibration curve was linear in the range 10-280 microg mL-1 for L-aspartic acid and 20-280 microg mL-1 for L-ornithine (for both amino acids, r=0.999). The method was validated by inaccuracy (bias) and precision (RSD) studies by analysing samples. The method was successfully applied to the quantitative determination of L-ornithine-L-aspartate in human plasma and could be useful for clinical and bioavailability investigations.

Comparative evaluation between capillary electrophoresis and high-performance liquid chromatography for the analysis of florfenicol in plasma

A capillary electrophoresis (CE) and a reversed phase high-performance liquid chromatography (RP-HPLC) method with UV detection have been developed for florfenicol analysis in plasma samples. The suitabilities of both methods for quantitative determination of florfenicol were approved through validation specification, such as linearity, precision, selectivity, accuracy, limit of detection and quantification. The capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) assay were compared by analyzing a series of plasma samples containing florfenicol in different concentrations using the two methods. The extraction procedure is simple and no gradient elution or derivatization is required. Furthermore, the analysis time of the CE method is two times shorter than the respective parameter in HPLC and solvent consumptions is considerably lower. The calibration curve were linear to at least 0.05-10 microg/ml (r = 0.9998) and 0.1-10 microg/ml (r = 0.9998) for CE and HPLC, respectively. The separation efficiency are good for both methods. The detection limits for florfenicol were 0.015 microg/ml with CE and 0.03 microg/ml with HPLC and CE method gave lower value, even though UV detector was applied in the both cases. The both methods were selective, robust and reliable quantification of florfenicol and can be useful for clinical and biomedical investigations.

The bioequivalence study of baclofen and lioresal tablets using capillary electrophoresis

A simple and robust analytical method for rapid separation and sensitive quantification of baclofen in human plasma by capillary electrophoresis technique was developed. Electrophoretic separation was optimized and successfully performed using simple sodium tetraborate aqueous solution. Observed detection limit in biological material was 10 ng. Using UV detection at 200 nm excellent linearity (r = 0.999) was observed over the concentration range from 0.025 to 1.0 microg mL(-1). The described method has been validated and applied to the quantitative determination of baclofen in human plasma. The bioavailability of Baclofen (Polpharma) and Lioresal (Novartis) in 18 healthy volunteers was investigated. The results indicate bioequivalence of the reference and Baclofen preparations.

Validated capillary electrophoretic method for the analysis of ivermectin in plasma after intragastric administration in pigs and horses

A capillary electrophoretic (CE) method has been developed for the determination of ivermectin (CAS 70288-86-7), a new generation drug with antiparasitic activity, in pig and horse plasma. The method was statistically validated for its linearity, accuracy, precision and selectivity. The linear range was from 1 to 30 ng mL(-1) with correlation coefficients greater than 0.999. The limit of detection was 0.3 ng mL(-1), while the quantitative limit was 1 ng mL(-1), using a 0.5 mL sample size. The validated procedure was used to determination of pharmacokinetic parameters of ivermectin after ingestion of 0.1 mg for pigs and 0.2 mg dose per kg body weight for horses, respectively. Studies were performed on a group of eight pigs and six horses. There were no significant differences between pigs and horses in any of the estimated pharmacokinetic parameters.

Capillary electrophoresis in analysis of veterinary drugs

Antibiotics are extensively applied in veterinary medicine for the treatment of various bacterial infections. Because of their use in food producing animals, the risk of occurrence of unwanted residues in edible products exists. To ensure human food safety, The European Union has defined maximum residue limits (MRLs) for veterinary drug residues in food products. Analytical methods need to be developed to confirm the presence of antibiotics at the MRL level. A capillary electrophoresis (CE) method with UV detection is proposed for the quantitative determination of residues from poultry and porcine tissues. Eight of the most frequently used antibiotics and nifursol, which routinely used as poultry coccidiostat, were analysed. CE technique permitted analysing substances to be separated from muscle, liver, kidney and skin with fat after a simple extraction with acetonitrile or ethyl acetate under basic conditions. Proposed method is capable to identify drug residues in tissues at level below 20 microg/kg.

[Complications after partial surgery for laryngeal cancer]

We present 45 patients with laryngeal carcinoma after partial various type laryngectomy results in 1989-1995. Frequency occurrence complication was dependent on localisation and expations. The most often complications after operation are; dyspnea which needs tracheotomy done and nor radicality in histopathological example which press the surgeon to make total laryngectomy. Authors present the types of conservative and surgical treatment of anatomical and functional reconstruction of larynx.

[Continuation of care after partial surgery for laryngeal cancer]

Removing of focus cancer in partial laryngectomy is going with the risk of local recurrence and the appearances of the next atypia cancer focus in the respiratory tract. Using of the new endoscopic methods can allow for total control in out patient department.