High-Performance Liquid Chromatographic Analysis of Sarcosine as a Fluorescent Levofloxacin Derivative.

Sarcosine, N-methyl glycine, could be used as a biomarker for the diagnosis of prostate cancer. It exists in biosamples at low levels; therefore, sensitive methods are necessary for its detection. In this study, we developed a sensitive and selective method for the analysis of sarcosine, based on derivatizing sarcosine with a fluorescent reagent levofloxacin acyl chloride.

Simultaneous determination of regular insulin and insulin aspart by capillary zone electrophoresis and application in drug formulations.

A rapid and simple capillary zone electrophoresis (CZE) with ultraviolet detection has been developed for simultaneous determination of regular insulin and insulin aspart in bulk and commercial injection dosage forms. The simultaneous analysis of the tested drugs was performed in phosphate buffer (80 mM; pH 6.5).

Expression of BUBR1 in human oral potentially malignant disorders and squamous cell carcinoma.

Objective: BUBR1 is one of the key components of the spindle assembly checkpoint (SAC) machinery and is activated in response to kinetochore tension. Defects in the SAC contribute to an increased rate of aneuploidization during tumorigenesis. The aim of the present study was to examine the immunohistochemical expression of BUBR1 protein for human oral squamous cell carcinogenesis.

A non-fluorescent derivative from derivatizing trans, trans-muconic acid with 2-(2-naphthoxy)ethyl-2-(piperidino)ethanesulfonate.

trans, trans-Muconic acid (MA) is a polar metabolite of benzene and used as a biomarker for monitoring human exposure to benzene. Because MA is a trace metabolite, sensitive method is required for its detection. In addition, MA is a highly polar compound with dicarboxyl functions that could incur unfavorable adsorption on silica-based stationary phase usually used for separation.

On-line microdialysis coupled with liquid chromatography for biomedical analysis.

This work presents a review of the microdialysis (MD) sampling technique for on-line coupling with high-performance liquid chromatography (HPLC) for biomedical analysis. MD-HPLC was first used in the field of brain metabolism to study neurotransmission, and this remains its common application in the biomedical field. On-line MD-HPLC hyphenated methods provide advantages over those with off-line MD-based techniques, including simplified sample preparation, automated analyses, avoidance of contamination introduced during the analytical process, and in situ analysis of the extracellular fluid of living organisms.

Automated on-line microdialysis sampling coupled with high-performance liquid chromatography for simultaneous determination of malondialdehyde and ofloxacin in whole blood.

We have developed a system that couples an on-line microdialysis (MD) system with flow injection high-performance liquid chromatography (HPLC)-fluorescence detection for simultaneous measurement of the concentrations of malondialdehyde (MDA) and ofloxacin (OFL) in whole blood samples. The sample matrix was first cleaned with an MD system using an MD probe. A continuously flowing dialysate stream was derivatized on-line and auto-injected into a separation column.

A simple micellar electrokinetic capillary chromatographic method for the quantitative analysis of organic expectorants.

A simple and rapid micellar electrokinetic capillary chromatographic method is described for the separation and quantification of five expectorant drugs, including ambroxol (AMB), bromhexine (BRM), carbocysteine, guaiacol and guaifenesin. The drugs were separated in a mixed solution of phosphate buffer (35 mM; pH 3.90) and acetonitrile (75:25, v/v) with sodium dodecylsulfate (120 mM) as the micellar source, and the separated drugs were directly monitored with UV detector (200 nm).

On-line microdialysis-nano-Au/TiO2-high-performance liquid chromatography system for the simultaneous determination of cobalt and nickel in water.

An on-line configuration of microdialysis (MD), Au/TiO2 nanoparticle preconcentration, and high-performance liquid chromatography-ultraviolet (HPLC-UV) detection method was developed for the simultaneous measurement of cobalt (Co) and nickel (Ni) concentrations in water. The sample matrix was first cleaned with an MD system using a MD probe. A continuously flowing dialysate stream was introduced into tubing coated with Au/TiO2 nanoparticles to adsorb metals, followed by elution by an acidic eluent.

Simultaneous determination of malondialdehyde and ofloxacin in plasma using an isocratic high-performance liquid chromatography/fluorescence detection system.

This study establishes the applicability of using high-performance liquid chromatography (HPLC) with fluorescence detection for the simultaneous determination of malondialdehyde (MDA) and ofloxacin (OFL). The MDA and OFL were separated through a reverse-phase C18 column (250 mm x 4.6 mm) at a flow rate of 1.

A simple and sensitive liquid chromatographic method for the analysis of free docosanoic, tetracosanoic and hexacosanoic acids in human plasma as fluorescent derivatives.

Docosanoic (C22), tetracosanoic (C24) and hexacosanoic (C26) acids are saturated very-long-chain fatty acids (VLCFA) present at trace levels in biosamples. VLCFA can be used as potential biomarkers for the diagnosis of hereditary diseases such as X-linked adrenoleukodystrophy. Because the analytes to be detected are at trace levels, a sensitive fluorimetric liquid chromatographic method was developed to analyze VLCFA in plasma.

Fluorescent high-performance liquid chromatographic analysis of vigabatrin enantiomers after derivatizing with naproxen acyl chloride.

Vigabatrin is widely used as an anticonvulsant in the treatment of seizures. Vigabatrin is usually supplied as racemate in formulation, but only the (S)-(+)-enantiomer of vigabatrin is pharmacologically active. A simple and sensitive liquid chromatographic method is described for the separation and quantification of vigabatrin enantiomers.

Trends in the use of lipid-lowering drugs by outpatients with diabetes in Taiwan, 1997-2003.

Purpose: To analyze recent trends in LLD use by outpatients with diabetes in Taiwan over a 7-year period and to see whether the trends are consistent with clinical trial outcomes and published guidelines.

Methods: A cross-sectional survey was implemented using the National Health Insurance Research Database between January 1997 and December 2003. Adult outpatients who had diagnoses of diabetes and dyslipidemia and who had concurrent antidiabetic drug and LLD claim were identified.

Effects of zinc compound on body weight and recovery of bone marrow in mice treated with total body irradiation.

This study aimed to investigate if zinc compound would have effects on body weight loss and bone marrow suppression induced by total body irradiation (TBI). ICR mice were divided randomly into two groups and treated with test or control compounds. The test compound contained zinc (amino acid chelated with bovine prostate extract), and the control was reverse osmosis pure water (RO water).

Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gamma-amino-n-butyric acid in human urine.

A simple and sensitive liquid chromatographic method is described for the analysis of gamma-amino-n-butyric acid (GABA) in human urine. GABA is increased in the urine of cancer patients and could be used as a biomarker in the diagnosis and treatment of related patients. The method is based on derivatizing GABA with a fluorescent reagent (naproxen acyl chloride) for transforming the non-chromophoric GABA to a derivative with chromophoric and fluorophoric properties.

Combining high-performance liquid chromatography with on-line microdialysis sampling for the simultaneous determination of ascorbyl glucoside, kojic acid, and niacinamide in bleaching cosmetics.

We have used on-line microdialysis sampling coupled with high-performance liquid chromatography and UV-vis detection to simultaneously determine the contents of ascorbyl glucoside (AA-2G), kojic acid (KA), and niacinamide (VitB(3)) in commercial bleaching cosmetics. Our results indicate that AA-2G, KA, and VitB(3) separated well within 4.5 min on a reverse-phase Hypersil Fluophase PFP column when eluting with 0.

A sensitive liquid chromatographic method for the analysis of isovaleric and valeric acids in urine as fluorescent derivatives.

A simple and sensitive isocratic liquid chromatographic method was developed for the analysis of isovaleric and valeric acids in human urine as biomarkers in metabolic acidosis. The method is based on the derivatization of isovaleric and valeric acids with a fluorescent reagent 2-(2-naphthoxy)ethyl-2-(piperidino)ethanesulfonate for labeling the analytes with the naphthoxy fluorophore. The resulting fluorescent derivatives of isovaleric and valeric acids were separated on a phenyl-hexyl column, using a mixed solvent of methanol-water-tetrahydrofuran (55:31:14, v/v) as the mobile phase.

Highly sensitive analysis of cholesterol and sitosterol in foods and human biosamples by liquid chromatography with fluorescence detection.

A simple and sensitive method is described for the quantitative analysis of important animal and plant sterols (cholesterol and sitosterol) by liquid chromatography with fluorimetric detection. The method is based on the derivatization of cholesterol and sitosterol with a fluorescent reagent (naproxen acyl chloride) in toluene. The resulting derivatives were isocratically separated on a C(8) column with a mixed solvent of methanol-isopropanol-water (90:5:5, v/v) as a mobile phase and monitored with a fluorimetric detector (excitation 231 nm and emission 352 nm).

Trends in the use of antihypertensive drugs by outpatients with diabetes in Taiwan, 1997-2003.

Purpose: To analyze trends in AHD-use by diabetic outpatients in Taiwan over a 7-year period (1997-2003) and to see whether the trends are consistent with clinical trial outcomes and published guidelines.

Methods: A cross-sectional survey was implemented using National Health Insurance Research Database between January 1997 and December 2003. Adult outpatients who had diagnoses of diabetes and hypertension and who had concurrent antidiabetic and antihypertensive drug claim were identified.

Real-time dynamic monitoring of nonprotein-bound copper in the blood.

To obtain real-time dynamic changes of non-protein-bound copper in the blood, we have developed an online microdialysis sampling system coupled with a flow-injection graphite furnace-atomic absorption spectrometer (FI-GFAAS). The analytical performances of the online system such as linearity, limit of detection, precision, and spiked recoveries were validated. Before the in vivo experiments, the in vivo recovery was conducted.

Micellar electrokinetic capillary chromatographic method for the separation and quantitation of multiple amino acids as naphthoxy derivatives in pharmaceutical formulations.

The MEKC method is described for the quantitative analysis of 17 amino acids (AA) in pharmaceutical products. The method is based on simply derivatizing the AA with (2-naphthoxy)acetyl chloride under mild conditions. The resulting derivatives were separated by MEKC with borate buffer (35 mM; pH 9.

Micellar electrokinetic capillary chromatographic method for the quantitative analysis of uricosuric and antigout drugs in pharmaceutical preparations.

A simple MEKC method is described for the separation and quantification of seven widely used uricosuric and antigout drugs, including allopurinol (AP), benzbromarone (BZB), colchicine (COL), orotic acid (OA), oxypurinol (OP), probenecid (PB), and sulfinpyrazone (SPZ). The drugs were separated in a BGE of borate buffer (45 mM; pH 9.00) with SDS (20 mM) as the micellar source and the separated drugs were directly monitored with a UV detector (214 nm).

Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma.

A simple and sensitive liquid chromatographic method is described for the quantitative analysis of gabapentin in human plasma. Gabapentin (GBP) is an anticonvulsant and widely used in the treatment of epilepsy. No peculiar chromophore is available on gabapentin moiety for direct analysis by absorption spectrophotometry.

Simultaneous determination of cefepime and L-arginine by micellar electrokinetic chromatography and applications to commercial injections.

A simple micellar electrokinetic chromatography (MEKC) with UV detection is described for simultaneous analysis of cefepime and L-arginine. The determination of cefepime and L-arginine in pharmaceutical preparations was performed at 25degreesC using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drugs were studied, including the pH and concentrations of the Tris buffer and SDS.

Simple fluorimetric liquid chromatographic method for the analysis of undecylenic acid and zinc undecylenate in pharmaceutical preparations.

A simple and selective liquid chromatographic method is described for the analysis of undecylenic acid (UA) and zinc undecylenate (ZnUA) in pharmaceutical preparations. The method is based on the derivatization of the analytes extracted from various samples with 2-(2-naphthoxy)ethyl 2-(piperidino)ethanesulfonate. The resulting derivative was analyzed by liquid chromatography with fluorimetric detection.

Microdialysis sampling coupled to on-line high-performance liquid chromatography for determination of arbutin in whitening cosmetics.

We have developed a method that uses on-line microdialysis sampling coupled with high-performance liquid chromatography (HPLC) to determine arbutin in whitening cosmetics. The optimum analytical conditions for microdialysis sampling were a probe length of 10mm and a dialysis flow-rate of 5 microl min-1. The accuracy (% bias) for intra-day (n=6) and inter-day (n=30, five consecutive days) analyses ranged from -8.