High performance liquid chromatography mass spectrometric method for the simultaneous quantification of pravastatin and aspirin in human plasma: Pharmacokinetic application

AbstractA rapid and sensitive liquid chromatography–tandem mass spectrometric (LC–MS/MS) assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma. Furosemide was used as an internal standard. Analytes and the internal standard were extracted from human plasma by liquid–liquid extraction technique using methyl tertiary butyl ether. The reconstituted samples were chromatographed on a Zorbax SB-C18 column by using a mixture of 5mM ammonium acetate buffer and acetonitrile (20:80, v/v) as the mobile phase at a flow rate of 0.8mL/min. The calibration curve obtained was linear (r≥0.99) over the concentration range of 0.50–600.29ng/mL for pravastatin and 20.07–2012.00ng/mL for aspirin. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.0min for each sample made it possible to analyze more than 400 human plasma samples per day. The proposed method was found to be applicable to clinical studies

Simultaneous determination of atorvastatin, metformin and glimepiride in human plasma by LCâMS/MS and its application to a human pharmacokinetic study

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric (LCâMS/MS) assay method has been developed and fully validated for the simultaneous quantification of atorvastatin, metformin and glimepiride in human plasma. Carbamazepine was used as internal standard (IS). The analytes were extracted from 200 μL aliquots of human plasma via protein precipitation using acetonitrile. The reconstituted samples were chromatographed on a Alltima HP C18 column by using a 60:40 (v/v) mixture of acetonitrile and 10 mM ammonium acetate (pH 3.0) as the mobile phase at a flow rate of 1.1 mL/min. The calibration curves obtained were linear (r2â¥0.99) over the concentration range of 0.50â150.03 ng/mL for atorvastatin, 12.14â1207.50 ng/mL for metformin and 4.98â494.29 ng/mL for glimepiride. The API-4000 LCâMS/MS in multiple reaction monitoring (MRM) mode was used for detection. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. All the analytes were found to be stable in a battery of stability studies. The method is precise and sensitive enough for its intended purpose. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The developed assay method was successfully applied to a pharmacokinetic study in human male volunteers. Keywords: Atorvastatin, Metformin, Glimepiride, LCâMS/MS, Human plasma, Pharmacokinetic

Time-dependent homeostatic mechanisms underlie brain-derived neurotrophic factor action on neural circuitry

Abstract Plasticity and homeostatic mechanisms allow neural networks to maintain proper function while responding to physiological challenges. Despite previous work investigating morphological and synaptic effects of brain-derived neurotrophic factor (BDNF), the most prevalent growth factor in the central nervous system, how exposure to BDNF manifests at the network level remains unknown. Here we report that BDNF treatment affects rodent hippocampal network dynamics during development and recovery from glutamate-induced excitotoxicity in culture. Importantly, these effects are not obvious when traditional activity metrics are used, so we delve more deeply into network organization, functional analyses, and in silico simulations. We demonstrate that BDNF partially restores homeostasis by promoting recovery of weak and medium connections after injury. Imaging and computational analyses suggest these effects are caused by changes to inhibitory neurons and connections. From our in silico simulations, we find that BDNF remodels the network by indirectly strengthening weak excitatory synapses after injury. Ultimately, our findings may explain the difficulties encountered in preclinical and clinical trials with BDNF and also offer information for future trials to consider