Biomedical subjects

N Mesplet

Publications and source records attributed to N Mesplet.

3 recordsLinked to original sources

PubMed2001

Simultaneous quantitation of nucleoside HIV-1 reverse transcriptase inhibitors by short-end injection capillary electrochromatography on a beta-cyclodextrin-bonded silica stationary phase.

As part of our on-going study of the analysis and quantitation of anti-HIV nucleosides, a capillary electrochromatography (CEC) method has been developed for the simultaneous quantitation of nucleoside HIV reverse transcriptase inhibitors (NRTIs), i.e. zidovudine (AZT), lamivudine (3TC), didanosine (ddA) and its administrated form (ddI), stavudine (d4T) and hivid (ddC). CEC on chiral stationary phase has mainly been dedicated to the separation of enantiomers. However, this paper explores an original application of a beta-cyclodextrin-bonded silica packed column, taking advantage of the internal hydrophobicity of the polysaccharide to separate the NRTIs. The influence of several parameters (pH buffer, ionic strength, acetonitrile content, temperature and voltage) has been investigated using the short-end injection technique to achieve baseline separation in a short-time analysis before quantitation.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed2001

Analysis of intracellular didanosine triphosphate at sub-ppb level using LC-MS/MS.

An analytical procedure has been developed for the analysis of intracellular didanosine triphosphate (ddATP). An electrospray ionization tandem mass spectrometer (ESI-MS) was interfaced to liquid chromatography (LC) using a mobile phase CH3OH/H2O (25/75) containing 1% formic acid for the analysis of the 5'-triphosphate metabolite of the antiviral didanosine. In this procedure, ddATP was extracted from CEM-T4 cells, isolated using an exchange anion solid phase extraction procedure, enzymatically dephosphorylated and then analyzed by LC-MS/MS within a 1 min run time. The influence of several parameters (electrospray ionization interface, acidic modifiers of the mobile phase) has been studied. A calibration curve was generated and the linear regression analysis yielded a regression coefficient (r(2)) greater than 0.999. Using LC-MS/MS detection in single reaction monitoring mode (SRM), the limit of quantitation of ddA in CEM-T4 cells was 0.02 ng ml(-1). Furthermore, this procedure could be used to perform simultaneous detection of five nucleoside reverse transcriptase inhibitors, such as AZT, 3TC, ddA, ddC and d4T and make LC-MS/MS a method of choice for Therapeutic Drug Monitoring (TDM) in a clinical environment.

Cells, Cultured↗

PubMed2000

Robustness testing for a capillary electrophoresis method using the "short-end injection" technique.

A multivariate approach for testing the robustness of a capillary electrophoresis method using the "short-end injection" technique is presented. Firstly, a Plackett and Burman (PB) design with 11 factors (eight real factors and three dummies) was used to identify the critical factors on resolution, plate number, plate count, asymmetry and assay. Then, the factors which were found to be significant were studied in a central composite design to predict the variation of resolution inside the area investigated in the PB design. PB and central composite designs yielded conclusions that were in good agreement with one another. They showed that the separation could be considered as robust, notwithstanding the fact that some factors where found to be statistically significant and should be controlled (injected volume and electrolyte concentration). Using the factor values which gave the worst-case situation for Rs still led to acceptable values for this parameter.

Electrophoresis, Capillary↗