SIMPLE HPLC-UV METHOD FOR DETERMINATION OF METFORMIN IN HUMAN PLASMA AND ERYTHROCYTES APPLICATION TO THERAPEUTIC DRUG MONITORING

Objective: The aim of this study was to develop a simple, rapid, efficient, cost effective and reproducible, stability indicating reverse phase high performance liquid chromatography method (RP-HPLC) for dosage of metformin in human plasma and erythrocytes. Methods: In this method, the plasma or erythrocyte proteins were precipitated using Perchloric acid: acetonitrile (50 % v/v) mixture and the supernatant liquid were injected into the HPLC system. The separation was achieved with a symmetry C8 column with the mobile phase containing 10 % water and 90 % sodium dihydrogen phosphate buffer (5.8 mM), the pH was adjusted to 3.8 with Phosphoric acid. The temperature was elevated to 25 °C. The detection was done by a UV detector at 232 nm. Results: The retention time was observed at around 4.412 min for metformin and 6.022 for lansoprazole an internal standard (IS). The response was linear over a range of 2-32µg ml-1, the coefficient of determination (r²) was found to be (r² =0. 9988). The lowest limit of quantification and detection was 0.1 µg/ml and 0.3 µg/ml respectively. No endogenous substances were found to interfere with the peaks of the drug. The intra-day and inter-day coefficient of variations was 2.1 % or less for all the selected concentrations. The relative errors at all the studied concentrations were 3.5 % or less. Conclusion: The HPLC method described in this article was simple, selective, reproducible, linear, and precise, it can be applied for therapeutic drug monitoring of metformin in human plasma and erythrocytes

Assessment of MALDI-TOF MS biotyping for Borrelia burgdorferi sl detection in Ixodes ricinus.

Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has been demonstrated to be useful for tick identification at the species level. More recently, this tool has been successfully applied for the detection of bacterial pathogens directly in tick vectors. The present work has assessed the detection of Borrelia burgdorferi sensu lato in Ixodes ricinus tick vector by MALDI-TOF MS. To this aim, experimental infection model of I. ricinus ticks by B. afzelii was carried out and specimens collected in the field were also included in the study. Borrelia infectious status of I. ricinus ticks was molecularly controlled using half-idiosome to classify specimens. Among the 39 ticks engorged on infected mice, 14 were confirmed to be infected by B. afzelii. For field collection, 14.8% (n = 12/81) I. ricinus ticks were validated molecularly as infected by B. burgdorferi sl. To determine the body part allowing the detection of MS protein profile changes between non-infected and B. afzelii infected specimens, ticks were dissected in three compartments (i.e. 4 legs, capitulum and half-idiosome) prior to MS analysis. Highly reproducible MS spectra were obtained for I. ricinus ticks according to the compartment tested and their infectious status. However, no MS profile change was found when paired body part comparison between non-infected and B. afzelii infected specimens was made. Statistical analyses did not succeed to discover, per body part, specific MS peaks distinguishing Borrelia-infected from non-infected ticks whatever their origins, laboratory reared or field collected. Despite the unsuccessful of MALDI-TOF MS to classify tick specimens according to their B. afzelii infectious status, this proteomic tool remains a promising method for rapid, economic and accurate identification of tick species. Moreover, the singularity of MS spectra between legs and half-idiosome of I. ricinus could be used to reinforce this proteomic identification by submission of both these compartments to MS