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Biomedical subjects

J Havel

Publications and source records attributed to J Havel.

47 records · Page 3Linked to original sources

Capillary zone electrophoresis determination of thyreostatic drugs in urine.

In this work, a new capillary zone electrophoresis (CZE) method has been developed for the analysis of thyreostatic drugs (TD) such as methylthiouracil (MTU), propylthiouracil (PTU), and thiouracil (TU) in urine specimens. An untreated fused-silica capillary tube (75 microns i.d., 57 cm total length, 49.5 cm length to the detector) was used in all of the experiments. Optimal conditions were found using 50 mM borate buffer, pH 7.6, applied voltage 15 kV, 25 degrees C, and 30 sec of hydrodynamic injection. UV detection at 276 nm was employed. Ethylacetate extraction of the compounds was made before the analysis of each urine sample. An electrostacking procedure to increase the sensitivity was applied. The method developed was used for the analysis of several thousands of samples as part of a veterinary control procedure (Institute for State Control of Veterinary Biological and Medicaments, Brno, Czech Republic). The following detection limits were reached: 0.3 ppm (PTU and MTU) and 0.5 ppm (TU). The standard deviation for PTU, MTU, and TU determination was 1.12, 0.98, and 3.8% rel., respectively.

Antithyroid Agents↗

Determination of drugs used as anti-Parkinson's disease drugs in urine and serum by capillary electrophoresis.

A new capillary electrophoresis method to determine simultaneously eight of the most important anti-Parkinson's disease compounds has been developed. The generic names of the drugs studied are benactyzine (BA), trihexyphenidyl (TP), fenpiverin (FP), diphemin (DF), scopolamine (BL), adiphenine (TS), diethylaminoethylester 1-phenylcyclopentane-1-carboxylate (EKK), and diethylaminoethylester tetramethoxydiphenylacetate (EKO). An untreated fused-silica capillary tube (75 microns i.d., 57 cm total length, 49.5 cm length to the detector) was used with detection at 190 nm. The optimal separation conditions were 50 mM phosphate buffer (pH 2.7) with 7 mM-beta-cyclodextrin, electrokinetic injection for 15 sec at 5 kV, temperature 25 degrees C, and 15-20 kV separation voltage. Complete separation of all compounds was achieved in less than 16 min. The procedure was applied for the determination in urine and serum. The limits of detection (LOD, S/N = 3) for serum were 209 (FP), 234 (EKO), 168 (DF), 182 (BA), 168 (TP), 220 (BL), 174 (TS), and 163 (EKK) ppb. The method can be used for the therapeutic drug monitoring of these central active cholinolytics in clinical laboratories.

Antiparkinson Agents↗

Characterization of a sapphire-epoxy coating for capillary electrophoresis.

A new procedure for coating capillaries for capillary electrophoresis applying a sapphire (alumina) containing epoxy resin was developed. Coated capillaries showed considerably reduced electroosmotic flow, and decreased the adsorption of proteins to the internal wall of the capillary. Coating is transparent down to 195 nm and can be used with advantage to analyze different kinds of substances, such as small cations and/or anions, and proteins.

Adsorption↗

Capillary zone electrophoresis determination of perphenazine in pharmaceutical preparations and in human serum.

Perphenazine belongs to the group of phenothiazine-based neuroleptic drugs frequently used in the long-term treatment of psychotic disorders. In this work, a new capillary zone electrophoresis (CZE) method for the rapid determination of perphenazine (PPZ) in pharmaceutical preparations and human blood serum was developed. Using solid-phase extraction (SPE) as a preclean/purification and preconcentration step before CZE analysis, a detection limit of 3 ng/mL for the monitoring of PPZ in blood serum (for a signal-to-noise ratio of 3) was reached.

Acetonitriles↗

High-performance capillary electrophoresis determination of pyrithione in antidandruff preparations and shampoos.

A simple and rapid high-performance capillary electrophoresis (HPCE) method for the determination of 2-mercaptopyridine-1-oxide (pyrithione) was developed. After addition of ethylenediaminetetraacetic acid (EDTA), pyrithione was determined in the form of the free anion using 50 mM borate (pH 9.2) as background electrolyte and was detected at 244 nm with a limit of detection (LOD) of 0.636 ppm (S/N = 3). The method was used to check the purity of pyrithione preparations and for the determination of pyrithione in shampoo.

Antifungal Agents↗