Biomedical subjects

Tímea Pap

Publications and source records attributed to Tímea Pap.

4 recordsLinked to original sources

PubMed2005

High-performance liquid chromatographic-tandem mass spectrometric method for the determination of clemastine in human plasma.

A highly sensitive high-performance liquid chromatographic-tandem mass spectrometric method (HPLC-MS-MS) has been developed to quantitate clemastine in human plasma for the purpose of pharmacokinetic studies. Sample preparation was carried out by liquid-liquid extraction using deuterated clemastine as an internal standard. Chromatographic separation used a C18 reversed phase polymer column giving an extremely fast total run time of 2 min. The method was validated and used for the bioequivalence study of clemastine tablets in healthy male volunteers (n=28). The lower limit of detection proved to be 0.01 ng/ml for clemastine.

Chromatography, High Pressure Liquid↗

PubMed2004

Binding assays with molecularly imprinted polymers--why do they work?

The design of homologous displacement ligand binding assays based on molecularly imprinted polymers (MIP) is discussed in terms of the MIP adsorption isotherm. It is shown that only MIPs having a binding isotherm with varying slope are suitable for the assay, but there is no need to interpret the isotherm in terms of site affinity and population. One can calculate the calibration plot of the binding assay from the isotherm and vice versa.

Calibration↗

PubMed2004

Characterization of the selectivity of a phenytoin imprinted polymer.

The selectivity of analytical methods based on molecularly imprinted polymers (MIPs) is due to the preferential adsorption of the analyte(s) as compared to other substances (interferences). This paper shows the theoretical and practical difficulties, which have to be considered and solved when real samples need to be analysed in a wide range of analyte and interferant concentrations. It is shown that the estimation of interference effects requires either many measurements or a realistic model of the adsorption equilibrium in mixed solutions of the analyte and the interferences. Examples are shown for positive (cooperative) interference effects, for better experimental design and interpretation of binary isotherm measurements and for establishing the chemical model of interference from selectivity measurements. The usual MIP model consisting of a cavity, which closely fits the shape of the template from all sides, appears unsuitable for this MIP, and it is replaced with a more realistic, more open model. The applicability of the results to using non-imprinted polymers as selective sorbents and to screening drug candidates is also shown.

Chromatography↗

PubMed2002

Effect of solvents on the selectivity of terbutylazine imprinted polymer sorbents used in solid-phase extraction.

A solid-phase extraction sample preparation method using a molecularly imprinted polymer (MIP) selective for the triazine type pesticide terbutylazine has been developed. The method involves preconcentration from large volumes of water samples on a C18 disk coupled to selective clean-up on the MIP. The method has been optimised by studying the recovery and retention of terbutylazine and some other structurally related triazine derivates as a function of the selective washing solvent used. The effect of the water content of the selective washing solvent was also investigated on the recovery of the MIP. River water samples were analysed with the coupled technique, and efficient clean-up of the samples was observed.

Polymers↗