Pharmaceuticals and Related Drugs

Immunoaffinity capillary electrophoresis as a powerful strategy for the quantification of low-abundance biomarkers, drugs, and metabolites in biological matrices

In the last few years, there has been a greater appreciation by the scientific community of how separation science has contributed to the advancement of biomedical research. Despite past contributions in facilitating several biomedical breakthroughs, separation sciences still urgently need the development of improved methods for the separation and detection of biological and chemical substances. In particular, the challenging task of quantifying small molecules and biomolecules, found in low abundance in complex matrices (e.g., serum), is a particular area in need of new high-efficiency techniques. The tandem or on-line coupling of highly selective antibody capture agents with the high-resolving power of CE is being recognized as a powerful analytical tool for the enrichment and quantification of ultra-low abundance analytes in complex matrices. This development will have a significant impact on the identification and characterization of many putative biomarkers and on biomedical research in general. Immunoaffinity CE (IACE) technology is rapidly emerging as the most promising method for the analysis of low-abundance biomarkers; its power comes from a three-step procedure: (i) bioselective adsorption and (ii) subsequent recovery of compounds from an immobilized affinity ligand followed by (iii) separation of the enriched compounds. This technology is highly suited to automation and can be engineered to as a multiplex instrument capable of routinely performing hundreds of assays per day. Furthermore, a significant enhancement in sensitivity can be achieved for the purified and enriched affinity targeted analytes. Thus, a compound that exists in a complex biological matrix at a concentration far below its LOD is easily brought to well within its range of quantification. The present review summarizes several applications of IACE, as well as a chronological description of the improvements made in the fabrication of the analyte concentrator-microreactor device leading to the development of a multidimensional biomarker analyzer.

Application of Porous Membrane-Protected Micro-Solid-Phase Extraction Combined with HPLC for the Analysis of Acidic Drugs in Wastewater

This report describes the use of a porous membrane-protected micro-solid-phase extraction (micro-SPE) procedure to extract acidic drugs from wastewater that are then determined by high-performance liquid chromatography with ultraviolet detection. The micro-SPE device consists of C18 sorbent held within a membrane envelope made of polypropylene. Ketoprofen and ibuprofen were selected as model compounds, and extraction parameters were optimized. Correlation coefficients of 0.9980 and 0.9953 were obtained for ketoprofen and ibuprofen, respectively, across a concentration range of 1-250 microg/L. Relative extraction recoveries were between 94 and 112%. The relative standard deviation of the analytical method ranged between 2 and 10%, respectively. The method detection limits for these target analytes in wastewater ranged from 0.03 to 0.08 microg/L. When compared to conventional solid-phase extraction (SPE), this new method showed better detection limits with good reproducibility. The results shows that this micro-SPE technique is a feasible alternative to multistep SPE for the extraction of analytes in complex samples.

New materials in sorptive extraction techniques for polar compounds

This paper provides an overview of the new developments in material and format technology that improve the extraction of polar compounds in several extraction techniques. They mainly include solid-phase extraction, but there are also other sorptive extraction techniques, such as stir bar sorptive extraction and solid-phase microextraction that use either fibers or in-tube devices. We focus on new synthesised materials that are both commercially available and "in-house". Most novel materials that enhance the extraction of polar compounds are hydrophilic and have large specific surface area; however, we also cover other leading technologies, such as sol-gel or monolith. We describe the morphological and chemical properties of these new sorbents so that we can better understand them and relate them to their capability of retaining polar compounds. We discuss the extraction efficiency for polar compounds when these polymers are used as sorptive material and compare them to other materials. We also mention some representative examples of applications.

Liquid chromatography/atmospheric pressure ionization mass spectrometry with post-column liquid mixing for the efficient determination of partially oxidized polycyclic aromatic hydrocarbons

The analytical hyphenation of micro-flow high-performance liquid chromatography (LC), with post-column liquid mixing and mass spectrometric detection (MS) was established to detect partially oxidized polycyclic aromatic hydrocarbons (oxy-PAHs) for low quantity samples. 100pmol injections of 30 reference standards could be detected in good sensitivity using either atmospheric pressure chemical ionization (APCI) and/or atmospheric pressure photoionization (APPI). The connected mass spectrometer was a single quadrupol analyzer realizing simultaneous registration of positive and negative ions in scan range width of 200 - 300Da. The ionization efficiency was compared using three ionization sources (incl. electrospray ionization (ESI)) for several oxy-PAHs. According to the mass spectra, the analytes behave differently in ionization properties. Ionization mechanism (e.g. deprotonated ions and electron captured ions) could be discussed with new inside views. Finally, the hyphenated system was applied to an exemplary aerosol extract and thus highlighting the expedient utilization of this downscaled method for real samples.