Info

Pawliszyn (Ed.), Sampling and Sample Preparation in Field and Laboratory Fundamentals and New Directions in Sample Preparation, Elsevier, Amsterdam, 2002. 45. H. Kataoka, Curr. Pharm. Anal, 2005, 1, 65. 46. M. Gilar, E.S.P. Bouvier, and B.J. Compton, J. Chromatogr. A, 2001, 909, 111. 47. E.M. Thurman and M.S. Mills, Solid-Phase Extraction Principles and Practice, Wiley, New York, 1998. 48. J.S. Fritz, Analytical Solid-Phase Extraction, Wiley-VCH, New York, 1999. 49. C.F. Poole, Trends...

Column Diameter

Column diameter is an important parameter to consider in life science applications in which sample amounts are very limited and the components of interest may not be abundant. Researchers have reviewed micro HPLC instrumentation and its advantages.910 Nano LC-MS offers 1000- to 34,000-time reductions in the dilution of a sample molecular zone eluted from nano LC columns of 25 to 150 m IDs in comparison to a 4.6 mm ID column. This represents a large enhancement of ion counts in comparison to...

Developments in column technology

HPLC columns can be divided into three broad categories depending on the packing materials used in construction that influence the flow patterns of the eluent through the packed bed and the mass transfer mechanisms that affect the solute as it partitions between the moving and stationary phases. The three types of packings are totally nonporous, porous nonreticulated, and porous reticulated materials. The latter two categories can be divided further into two additional groupings. The two types...

Formats for Rapid andor High Throughput Solid phase Extraction of Drugs in Biological Matrices

With the advent of fast analytical techniques such as LC MS MS, 96-well plate formats gained preference around 1995 to cater to the high-throughput sample preparation needs of bioanalysis. The historical development of these 96-well plate formats was well documented by Wells42 and will not be detailed here. In this well format, the sorbent is packed at the bottom of the plate with popular bed mass sizes ranging from 10 to 500 mg. Further refinements of this 96-well flow-through system include...

Overview ANALYTicAL METHods For TDM

TDM was first carried out on drugs in biological samples using ultraviolet (UV) light, fluorescence, and electrochemical detection, which measured physicochemical properties of drugs. Used alone, these detection methods had low sensitivity and selectivity and were soon obsolete.10 Since its invention in the late 1960s, gas chromatography (GC) has proven very useful for TDM.1,11-15 First, a drug is extracted from a biological fluid with an organic solvent, derivatized before or after extraction,...

Fourier Transform Ion Cyclotron Resistance Fticr Ms

This is a very powerful MS analyzer that determines the m z ratios of ions based on their cyclotron frequencies in a fixed magnetic field. The distinctive property of FTICR is that the ion trapping cell is surrounded by a magnetic field within which entrapped ions can resonate at their cyclotron fre-quencies.28 Ions in FTICR can be focused into coherent packets and can then be excited to a larger cyclotron radius by an oscillating electrical field. An image current is generated by the ions as...

Rrt

FIGURE 7.3 Conventional dosing versus cassette dosing. With conventional dosing, only one compound is dosed into each rat. Cassette dosing involves multiple compounds dosed in each rat. (Source Adapted from Manitpisitkul, P. and White, R.E., Drug Dis. Today, 2004, 9, 652. With permission of Elsevier.) Another sample reduction method still employed by some companies is the technique called cassette dosing.90-99 As shown in Figure 7.3,92 a group of compounds (typically 5 to 10) are dosed together...

Interactions of sorbent and Analyte in sPE and selective Extractions Based on sorbent Chemistry

The interactions of a sorbent and an analyte fall into three classes hydrophobic (also called dispersive or van der Waals interactions with associated energy of 1 to 5 kJ mol), polar, and ionic. Polar interactions are further divided into dipole-induced dipole (2 to 7 kJ mol), dipole-dipole (5 to 10 kJ mol), hydrogen bonding (10 to 25 kJ mol), and ion-dipole (10 to 50 kJ mol). Ionic interactions are electrostatic with the highest associated energy levels of 50 to 500 kJ mol. These energy values...

References

Laboratory automation for compound optimization and early development drug metabolism A Wyeth case study. Am. Drug Discov. 1 27. 2. Herbst, J.J. and Dickinson, K. 2005. Automated high-throughput ADME Tox profiling for optimization of preclinical candidate success. Am. Pharm. Rev. 8 96. 3. DeWitte, R.S. and Robins, R.H. 2006.A hierarchical screening methodology for physicochemical ADME Tox profiling. Expert Opin. Drug Metab. Toxicol. 2 805. 4. MDL Information Systems,...

Introduction

Today's pharmaceutical industry faces the unprecedented challenge of surviving and succeeding in an increasingly complex, competitive, global business environment in which research and development (R& D) costs have skyrocketed and development and regulatory approval times have continuously lengthened despite flat revenue growth. According to analyses released by the Tufts Center for the Study of Drug Development, the fully capitalized cost to develop a single novel pharmaceutical (including...

P

P1A2 enzyme, 320-321 P2C9 enzyme, 239, 320-321 P2C19 enzyme, 239, 320-321 P2D6 enzyme, 239, 320-321 P3A4 enzyme, 239, 240, 287, 320-321 P450 enzyme fast gradient LC MS screening of, 325 induction assay, 240 inhibition assay, 208, 239-240, 320-321 in metabolic stability assay, 141 PLC analysis of, 197, 197 PAHs and, 20 Packed column supercritical and enhanced fluidity liquid chromatography (pcSFC), 76 See also Supercritical fluid chromatography Paclitaxel, 286 PAHs, 20-21, 283, 285, 361...

Parallel Systems

Dual SPE cartridges allow shortening of sample run cycle time by starting the second injection and extraction on the second TFC column while the first remains online for elution. Xia et al. (2000) developed a ternary column online SPE LC MS MS method to quantitate a drug candidate in rat plasma. Two Oasis HLB (50 x 1 mm, 30 m, Waters) cartridges and a Symmetry C18 column (50 x3.9 mm, 5 m, Waters) were connected with a ten-port switching valve. The plasma sample was first injected into cartridge...

Online Solid Phase Extraction as Tool for High Throughput Applications

Features that make online SPE more attractive compared to off-line SPE consist of Direct elution of analyte from extraction cartridge into LC system Elimination of time-consuming evaporation, reconstitution, and preparation for injection Achievement of maximum sensitivity for detection because the entire volume of eluate is utilized for analysis Processing of samples and SPE cartridges in a completely enclosed system, allowing protection for light- and air-sensitive compounds and preventing of...

Role of DMPK Screening in Lead Optimization

The three states of drug discovery are (1) target identification, (2) lead selection, and (3) lead optimization. Lead compounds identified by screening efforts are further optimized through the close collaboration of medicinal chemistry, exploratory drug metabolism, and drug safety assessment. As a segment of lead optimization, DMPK studies are becoming increasingly important based on the high attrition rate in later phases of drug development due to poor DMPK properties.27,28 The...

Stable Isotope Labeling in Cell Culture SILAC

Another useful strategy that utilizes different isotopes of the same element for proteomic quantification is known as stable isotope labeling with amino acids in culture (SILAC).58 59 This technique entails culturing of cells from two distinct biologic conditions in parallel culture media that lack natural amino acids and are supplemented with an synthetic amino acid that contains only one distinct isotope of an element (12C, 13C 14N, 15N, respectively). The two cell populations meta-bolically...

Automated Sample preparation

Sample preparation represents a major challenge and a very important step in the development and application of an analytical method. It is still considered the most labor-intensive, time-consuming, and error-prone step.219 Although the technology advancements discussed above have significantly boosted the throughputs of chromatographic and spectroscopic techniques for pharmaceutical analysis, sample preparation often remains a data generation bottleneck. Robotic systems that enable processing...

Small particle Liquid Chromatography

The standard formats of analytical HPLC columns in pharmaceutical R& D laboratories of 150 and 250 mm x 4.6 mm columns packed with 5 m or 3.5 mm particles with plate numbers (N) of 17,000 to 20,000 (for well behaved small molecules) are sufficient for most separations.6 The maximum resolving power of these columns is achieved when the run time is 30 to 60 min at an optimum flow rate of 1 mL min.7 The simplest approach to fast HPLC analysis is to use shorter columns because separation time is...

M

O Macroglobulin, 4 Magnesium, 4, 198 Magnetic sector mass spectrometers, 144 Maleate, 255 Maprotiline, 14-15 Marijuana, 8 Mass defect filtering (MDF), 146, 223-224, 226 Mass spectrometers (MS) accuracy of, 381 cassette dosing for See Cassette dosing acquisition rate, 106-108, 107, 114 ease of analysis of, 94, 199 processing of, 135 description of, 3-5, 327, 379 DESI, 74-75, 139, 268 detection enhancement factor, 360 factors affecting, 5-6 FTICR, 383 FT ICR MS, 116 high resolution sector, 144...

Software improvements for metabolite identification

To meet the demands of high-throughput metabolite identification in drug discovery, not only have new liquid chromatography and mass analyzers been introduced but also software programs for the automation of metabolite detection, acquisition of MS MS spectra, and interpretation of MS MS data have greatly improved. More than a decade ago, Cole et al. developed a rapid automated biotransformation identification (RABID) procedure that represented a breakthrough in the development of automated LC...

MoDificATioNs of Online Spe Lcmsms

In addition to online filters and precolumns, a simple protein precipitation step often precedes online SPE LC MS MS to prolong cartridge life. Protein precipitation can also reduce analytical interference and shorten chromatographic separation time. Since an internal standard IS solution is often added to plasma samples and centrifugation is used to remove possible particles before loading into the autosampler, protein precipitation does not add labor to the process. A common practice is to...

Contributors

Abbott Laboratories Abbott Park, Illinois, USA Department of Pathology University of Michigan Medical School Ann Arbor, Michigan, USA Abbott Laboratories Abbott Park, Illinois, USA Agilent Technologies Waldbronn, Germany Brehm Research Laboratory Wright State University Fairborn, Ohio, USA Engineering Division Nanostream, Inc. Pasadena, California, USA Exploratory Drug Metabolism Schering-Plough Research Institute Kenilworth, New Jersey, USA Abbott Laboratories Abbott Park, Illinois, USA Merck...

Online sample preparation

Because of the short liquid flow path of nano LC and the small orifice spray tip of the MS interface, column and flow path plugging is a common problem with nano LC-MS. Sample clean-up is critical for ensuring reliable daily operation and generation of quality data. Online desalting and particle filtering are particularly important steps. Four online sample clean-up factors should be considered with nano LC 1. Dead volume could cost long gradient delay bypass with valve switching should be...

Online sample cleanup

Everolimus, a derivative of sirolimus, is a novel macrocyclic immunosuppressant. Risk of acute rejection increases when the everolimus trough level falls below 3 mg L in renal transplant patients.46 FIGURE 11.8 Switching valve set-up. Source From Korecka, M. et al., Ther Drug Monit. 28, 485, 2006. With permission. To improve long-term outcomes, it is critical to perform TDM of everolimus levels in patients under therapy. Korecka et al.47 developed a sensitive high-throughput HPLC-MS MS method...

Column Length

Theoretically, chromatographic resolution depends on the square root of the column length. Separation of small molecules may be improved 40 by doubling column length. Retention time may also FIGURE 14.1 One-minute fast elution of three small molecules from a 5 cm x 1 mm column packed with 5 mm C18 particles. Column head pressure at 180 mL min flow rate is 2800 psi. Solvent composition is 60 40 water acetonitrile. FIGURE 14.1 One-minute fast elution of three small molecules from a 5 cm x 1 mm...

Highthroughput quantitative bioanalysis in large molecule dmpk

The DMPK parameter optimizations for large molecule drugs such as proteins and peptides are similar to those for small molecules except that metabolic profiling may not be involved in compound development unless unnatural amino acids are expected in the metabolic products or pathway. Using high throughput for large molecules quantitative analysis is not as well explored as its application for small molecules due to the analytical challenges associated with large peptides and proteins. For small...

SpE cartridge selection

Cartridges with different SPE mechanisms reversed-phase or ion exchange , binding strength degree of hydrophobicity , and binding capacities are available for selection. The introduction of polymer-based SPE sorbents greatly increased the choices beyond conventional silica-based materials Hennion 1999 Hsieh 2004 . When choosing SPE cartridges, loading capacity along with the need to balance retention of and adsorption of all analytes are factors to consider. An ideal SPE cartridge should have...