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Automated LC/MS/MS Bioanalysis of β-blockers in Human Plasma

Mixtures of biological compounds with varying partition coefficients (log P) present difficulties in preparation for liquid chromatography with tandem mass spectrometry (LC/MS/MS) analysis, owing to interference from lipids and proteins. It is, therefore, essential that analyte-independent methods are used for sample preparation including precipitation techniques, and that these systems should be rapid and easy to automate. 


Chromatographic Methods for The Therapeutic Monitoring of Amitriptyline and Its Active Metabolite Nortriptyline

Amitriptyline (3-(10,11-dihydro‑5H ‑dibenzo[a,d]cycloheptene-5-ylidene)-N,N-dimethylpropan-1-amine) is a centrally acting re-uptake inhibitor of various neurotransmitters. Its complex pharmacodynamic profile makes it a potent antidepressant, as well as a drug with versatile adverse effects. Its therapeutic range has been established along with its active metabolite nortriptyline (also marketed separately) as 120–250 ng/mL


Chromatographic Methods for The Therapeutic Monitoring of Amiodarone and Its Active Metabolite N-desethylamiodarone

Amiodarone (AMD) ((2-{4-[(2-butyl-1-benzofuran-3-yl)carbonyl]2,6-iiodophenyl}ethyl)diethylamine) is a Class III antiarrhythmic drug according to the Vaughan Williams classification scheme. Currently, this substance is considered as one of the most powerful antiarrhythmic agents. It is marketed in several countries for treating ventricular and supraventricular arrhythmias. In addition, it seems like amiodarone may be beneficial in various life-threatening syndromes such as cardiac arrest and post-myocardial infarction status


Selective Therapeutic Monitoring of Drugs and Their Pharmacologically Active Metabolites by Liquid Chromatography

Following administration the majority of pharmaceutical substances undergo metabolism. Some of the emerging metabolites bear significant pharmacological activity, giving rise to a complex pharmacological profile which can be controlled effectively in certain cases only by monitoring the blood levels of both the parent and the active transformation products.


Ion Chromatography with Pulsed Amperometric Detection for Determining Intestinal Permeability to Lactulose and Mannitol

This article explains how it is possible to detect lactulose and mannitol in urine easily and reliably using an ion chromatograph with pulsed amperometric detection. The lactulose/mannitol test is used to diagnose leaky-gut syndrome and chronic inflammatory bowel diseases associated with it.


Ion Chromatography coupled to Universal Detectors for The Analysis of Pharmaceutically-related Anions

This article demonstrates the potential of ion chromatography (IC) as a complementary separation method to reversed-phase high performance liquid chromatography (HPLC) for the determination of impurities in pharmaceutical active ingredients.


Implementing Robustness Testing for HPLC Methods: Part 1

This article is the first in a series about a practical approach to the implementation of robustness testing for HPLC analytical methods. In this first article the concept of robustness is introduced and an overview of the procedure for investigation of robustness is described. In subsequent articles practical advice will be provided on how to perform robustness testing following the described procedure.


Size-Exclusion Ultra Performance Liquid Chromatography for the Analysis of Covalent High Molecular Weight Insulin

This article describes the advantages realized by using a 125 Å pore size, sub-2-µm ethylene-bridged hybrid (BEH) silica packing material and a low dispersion UHPLC system for the analysis of high molecular weight (HMW) protein in therapeutic insulin samples. Among these advantages are faster run times, higher sensitivity, and higher resolving separations of insulin and covalent insulin HMW, while at the same time greatly reducing acetonitrile containing waste-stream volumes. 


Optimization of Analytical Methods Using Factorial Designs -- Part 2: A Deeper Look at Factorial Designs

In the first article in this series on using factorial designs for optimization of analytical methods, we examined the basic principles of factorial designs and its advantages over the traditional one-factor-at-a-time optimization approach. In this article, we will take a look at some important concepts related to factorial designs, as well as examine several factorial designs that can be easily implemented in the laboratory as an efficient, cost-effective and simple approach to analytical method optimization.


Optimization of Analytical Methods Using Factorial Designs -- Part 1: An Introduction

The conventional approach for optimizing analytical methods in the laboratory is the one-factor-at-a-time approach, where each experimental factor or parameter is optimized separately and independently of other factors. In contrast, factorial designs involve simultaneous optimization of all factors at once. Factorial designs offer a simple, efficient, and statistically valid method for optimizing analytical methods. In this article, the first of a three-article series, we will take an introductory look at factorial designs and its benefits to the analytical laboratory.


Implementing Robustness Testing for HPLC Methods: Part 3 -- Mobile Phase Buffers

When testing the robustness of an HPLC method, factors which may have an effect on the routine performance of the method are investigated. Previously, the effect of the organic volume fraction of the mobile phase for reversed phase methods was considered. In this article, we stay with reversed phase HPLC, and consider the effect of buffers used in the mobile phase.


Considerations in the Development of Chromatographic Methods to Assist Individualized Pharmacotherapy

The revolutionary emergence of novel fields in the framework of systems biology referred to as “omics” (genomics, proteomics, metabolomics etc.) has started driving clinical sciences towards a concept called personalized medicine ((also referred to as individualized medicine).


UHPLC-MS: An Efficient Method for the Determination of Illicit Drugs

The illicit drugs trade generates one of the largest global revenues at around $322 billion, according to the UN World Drug Report, 2009 [1]. Posing a major threat to the pharmaceutical industry and patients worldwide, illicit drugs are falsified medicinal products that contain either sub-standard or falsified ingredients, or ingredients in the wrong dosage. The main illicit drugs are the opiates (mostly heroin), cocaine, cannabis, and amphetamine-type stimulants (ATS) such as amphetamines, methamphetamine and ecstasy. Illicit drugs are listed under five categories namely narcotics, stimulants, depressants, hallucinogens and cannabis. These categories include many drugs legally produced and prescribed by doctors as well as those illegally produced and sold outside of medical channels [2].


Blood Spot Analysis

Q: “I am finding that I get poor PK data using plasma bioanalyses because of stress placed on the animal. Is there an alternative sampling technique?”


High-throughput Screening Method for Multiple Classes of Antibiotics in Milk

Veterinary drugs are widely used to prevent the outbreak of disease in livestock and are commonly found in feed additives or in drinking water. In addition, veterinary drugs are given to treat diseases, for drying-off purposes or to prevent losses during transportation.