A versatile and automatic on-line screening method: Transverse diffusion of laminar flow profiles-based capillary electrophoresis for exploring PTP1B inhibitors in natural products.

Natural products (NPs) play an important role in drug discovery and drug development due to their diverse chemical properties and biological activities. In the present work, an on-line capillary electrophoresis (CE) method was developed and applied to screen protein tyrosine phosphatase 1B (PTP1B) inhibitors in NPs. As a generic technique, transverse diffusion of laminar flow profiles (TDLFP) was utilized to mix all reactants in the capillary for on-line enzymatic reaction.

Nitrogen dioxide sterilization of a set of five ophthalmic active pharmaceutical ingredients: Impact on impurity profile and content.

Literature about sterilization of pharmaceutical substances is limited. The aim of this study was to evaluate the effect of nitrogen dioxide (NO) sterilization, a new emerging technology, on five different ophthalmic active pharmaceutical ingredients, i.e.

Novel multiple extraction thermal desorption approach prior to gas chromatography for the determination of residual solvents applied to modified cellulose.

In this work, multiple extraction thermal desorption (METD), as a sample introduction method for GC, was developed. This technique was used for the determination of residual solvents (RS) in modified cellulose, because it is practically impossible to dissolve or distribute it uniformly in water and common organic solvents. Moreover, METD facilitates the optimization of the desorption time and it is more sensitive to quantify trace level volatiles in insoluble material, compared to direct dynamic desorption (DDD).

Raman spectroscopy: A promising analytical tool used in human reproductive medicine.

Over the past few years, there has been growing interest in developing new methods of embryo quality assessment to improve the outcomes of assisted reproductive technologies in the medical field. Raman microscopy as an increasingly promising analytical tool has been widely used in life sciences, biomedicine and "omics" to study molecular, biochemical components, living cells and tissues due to the label-free and non-destructive nature of the imaging technique. This paper reviews the analytical capability of Raman microscopy and applications of Raman spectroscopy technology mainly in reproductive medicine.

Development and Validation of Liquid Chromatographic Method for Fast Determination of Lincomycin, Polymyxin and Vancomycin in Preservation Solution for Transplants.

In this study, a liquid chromatographic method was developed for the fast determination of lincomycin, polymyxin and vancomycin in a preservation solution for transplants. A Kinetex EVO C18 (150 × 4.6 mm, 2.

Quantification of amino acids secreted by yeast cells by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

Monitoring the levels of amino acids (AAs) in biological cell cultures provides key information to understand the regulation of cell growth and metabolism. Saccharomyces cerevisiae can naturally excrete AAs, making accurate detection and determination of amino acid levels within the cultivation medium pivotal for gaining insights into this still poorly known process. Given that most AAs lack ultraviolet (UV) chromophores or fluorophores necessary for UV and fluorescence detection, derivatization is commonly utilized to enhance amino acid detectability via UV absorption.

Development and validation of a simple and affordable LC-UV method for identification and assay of selected antimicrobial medicines.

Antimicrobials, particularly antibiotics, are among the most common classes of drugs reported as substandard and falsified (SF) in developing countries. Therefore, it is important to develop simple and affordable analytical methods for the quality control of antimicrobial medicines. In this study, a liquid chromatographic method with ultraviolet detection (LC-UV) was developed and validated for the screening and quantification of 13 antimicrobial medicines and one beta-lactamase inhibitor in pharmaceutical formulations.

A fast and efficient method for screening and evaluation of hypoglycemic ingredients of Traditional Chinese Medicine acting on PTP1B by capillary electrophoresis.

As a pivotal enzyme that regulates dephosphorylation in cell activities and participates in the insulin signaling pathway, protein tyrosine phosphatase 1B (PTP1B) is considered to be an important target for the therapy of diabetes. In this work, a rapid and efficient inhibitor screening method of PTP1B was established based on capillary electrophoresis (CE), and used for screening and evaluating the inhibition effect of Traditional Chinese Medicine on PTP1B. Response Surface Methodology was used for optimizing the conditions of analysis.

Impact of diluents on the calibration of direct dynamic thermal desorption prior to gas chromatography.

A thermal desorber (TD) can be used in different ways to introduce samples in a gas chromatographic (GC) system. Besides its conventional use where the collected analytes are released from the sorbent in the sample tube, direct dynamic desorption (DDD) is an interesting option where a solid sample is put directly in the TD tube. However, since no sorbent is used for the sample, proper calibration is not straightforward.

Determination of inorganic ions and carbohydrates in cardioplegia and nephroplegia solutions by ion chromatography.

In this study, methods for analyzing inorganic ions and carbohydrates in cardioplegia and nephroplegia solutions were developed and validated using ion chromatography with both conductivity and pulsed amperometric detection. The inorganic ions such as sodium, potassium, and calcium were separated by a cation-exchange column with 27 mM methanesulfonic acid as mobile phase at 0.5 mL/min.

A comprehensive review of capillary electrophoresis-based techniques for erythropoietin isoforms analysis.

Different CE techniques have been used to analyze erythropoietin. These techniques have been shown to be effective in differentiating and quantifying erythropoietin isoforms, including natural and recombinant origins. This review provides a comprehensive overview of various capillary electrophoresis-based techniques used for the analysis of erythropoietin isoforms.

Overview of chromatographic and electrophoretic methods for the determination of branched-chain amino acids.

The significance of branched-chain amino acids in diseases was clearly shown over the years. This review aims to describe the available techniques for their analytical determination. The article provides examples of the use of various analytical methods.

Simultaneous determination of ceftazidime and pyridine in human plasma by LC-UV.

A sensitive, accurate and precise liquid chromatography (LC) method for the simultaneous determination of ceftazidime and pyridine in human plasma has been developed and validated. Acetonitrile (ACN) was employed to precipitate the proteins in the plasma samples. Chromatographic separation was performed with a Kinetex® C18 (150 mm × 3 mm, 2.

Indoleamine 2,3 dioxygenase 1 immobilization on magnetic nanoparticles for screening inhibitors from coffee.

In this study, a ligand fishing method was developed to screen potential indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors from coffee extracts by immobilization of IDO1 enzyme on amino-modified magnetic nanoparticles combined with UHPLC-Q-TOF-MS/MS analysis. Parameters including enzyme concentration, immobilization time, the pH of glutaraldehyde and the amount of magnetic nanoparticles were optimized. The results indicated that immobilized IDO1 could be reused 5 times and was stable during storage for 7 days.

Differentiation of tetracyclines and their 4-epimers by mass spectrometry of the alkali metal adduct ions.

Tetracyclines (TCs) are a family of broad-spectrum antibiotics. During the manufacturing process or storage, epimerization of tetracyclines could occur, leading to 4-epimers which are nearly inactive. From an analytical point of view, isomers are often difficult to distinguish.

Screening assays for tyrosine kinase inhibitors: A review.

Tyrosine kinases have been intensively investigated as drug targets for several decades, since they regulate many cellular processes including cell growth, differentiation, and proliferation. Indeed, the deregulation of tyrosine kinases has been confirmed to play a vital role in the pathophysiology of many diseases. During the last few years, varieties of techniques have been developed to search for new tyrosine kinase inhibitors for cancer therapy, such as traditional filtration binding assay, scintillation proximity assay and some high-throughput screening methods.

Off-line and on-line liquid chromatography-mass spectrometry methods with immobilized bio-macromolecules for drug screening from natural sources.

Natural products are an important source of major compounds in drug discovery. Currently, rapid screening and identification of bioactive compounds is a challenge due to the complicated chemical composition of natural products. Affinity screening methods based on liquid chromatography coupled with mass spectrometry have seen increasing interest in the past few years.

Determination of Inorganic Ions in Parenteral Nutrition Solutions by Ion Chromatography.

A new, simple and sensitive ion chromatography (IC) method for the determination of sodium, potassium, magnesium, calcium and chloride in a parenteral nutrition (PN) solution was developed and validated. Before sample analysis, a sample pretreatment by calcination was applied which could totally remove interference from other constituents of the PN solution. Methanesulfonic acid (MSA) and sodium hydroxide were used as the mobile phase for the determination of cations and anions, respectively.

Migration study of phenolic endocrine disruptors from pacifiers to saliva simulant by solid phase microextraction with amino-functionalized microporous organic network coated fiber.

Parabens, bisphenols, and triclosan are used in many baby products, including pacifiers. However, the migration through oral saliva will result in a potential health risk. The present study proposes a sensitive and simple method for the analysis of these chemicals in saliva simulants by solid phase microextraction (SPME) with amino-functionalized microporous organic network (MON-NH) coated fiber.

A disease-associated missense mutation in CYP4F3 affects the metabolism of leukotriene B4 via disruption of electron transfer.

Background: Cytochrome P450 4F3 (CYP4F3) is an ω-hydroxylase that oxidizes leukotriene B4 (LTB4), prostaglandins, and fatty acid epoxides. LTB4 is synthesized by leukocytes and acts as a chemoattractant for neutrophils, making it an essential component of the innate immune system. Recently, involvement of the LTB4 pathway was reported in various immunological disorders such as asthma, arthritis, and inflammatory bowel disease.

Hollow fiber membrane-protected amino/hydroxyl bifunctional microporous organic network fiber for solid-phase microextraction of bisphenols A, F, S, and triclosan in breast milk and infant formula.

Bisphenols and triclosan have been used in various products, and exposure to these chemicals may affect human health. The present study proposes a sensitive method for the determination of bisphenols A, F, S, and triclosan. The fiber was coated by amino/hydroxyl bifunctional microporous organic network and protected by polyvinylidene fluoride hollow fiber membrane for direct immersion solid phase microextraction.

Determination of pesticide residues in chilli and Sichuan pepper by high performance liquid chromatography quadrupole time-of-flight mass spectrometry.

In this study, a multi-component analytical method for the detection of pesticide residues in chilli and Sichuan pepper by high performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (LC-Q-TOF/MS) was developed and validated. The sample preparation is based on an extraction step with acetonitrile followed by a cleanup step using primary secondary amine, C, graphitized carbon black and anhydrous magnesium sulfate. Values of matrix effects ranged from -55.

The effect of Gamma and Ethylene Oxide Sterilization on a Selection of Active Pharmaceutical Ingredients for Ophthalmics.

Ensuring the sterility of life science products plays a pivotal role in the healthcare sector. Gamma irradiation and ethylene oxide sterilization are two commonly applied methods for the sterilization of medical devices, packaging components and Active Pharmaceutical Ingredients (API) for medicinal products. Focussed studies on the effects of sterilization processes on APIs remain limited.