Fully automated 96-well liquid-liquid extraction for analysis of biological samples by liquid chromatography with tandem mass spectrometry

Strategies for automating analytical and bioanalytical laboratories

Analytical measurement methods are used in different areas of production and quality control, diagnostics, environmental monitoring, or in research applications. If direct inline or online measurement methods are not possible, the samples taken have to be processed offline in the manual laboratory. Automated processes are increasingly being used to enhance throughput and improve the quality of results. In contrast to bioscreening, the degree of automation in (bio)analytical laboratories is still low. This is due in particular to the complexity of the processes, the required process conditions, and the complex matrices of the samples. The requirements of the process to be automated itself and numerous other parameters influence the selection of a suitable automation concept. Different automation strategies can be used to automate (bio)analytical processes. Classically, liquid handler-based systems are used. For more complex processes, systems with central robots are used to transport samples and labware. With the development of new collaborative robots, there will also be the possibility of distributed automation systems in the future, which will enable even more flexible automation and use of all subsystems. The complexity of the systems increases with the complexity of the processes to be automated.

In-line sample trap columns with diatomite for large-volume injection in CZE-IM-MS

The analysis of low-abundant compounds with capillary zone electrophoresis-drift-tube ion mobility spectrometry-mass spectrometry (CZE-DTIMS-MS) is compromised due to the low injectable sample volumes in CZE and low duty cycle in DTIMS. Fritless packed in-line trap columns, using solid-phase extraction sorbent particles, have been used to increase injection volumes in CZE, but these columns are difficult to prepare and exhibit rapidly increasing back pressures. To provide smooth and complete filling of trap columns as well as to ensure higher and sustained flow rates though the columns, blends of cation and anion exchange particles with diatomite were used. The application of diatomite blends ensured the use of trap columns for at least 100 injections, with maximum injection volumes over 10 µl, which corresponds to an enrichment factor of more than 1000 over conventional injections in CZE-MS, enabling the detection of low nM concentrations of N-glycans with CZE-IMS-MS.

Liquid Chromatographic Methods for COVID-19 Drugs, Hydroxychloroquine and Chloroquine

COVID-19 has been a threat throughout the world since December 2019. In attempts to discover an urgent treatment regime for COVID-19, hydroxychloroquine (HCQ) and chloroquine (CQ) have been on solidarity clinical trial. However, many countries have pulled HCQ and CQ from their COVID-19 treatment regimens recently, some countries still continue using them for patients who have previously started HCQ and CQ and they may complete their course under the supervision of a doctor. HCQ and CQ are 4-aminoquinoline drugs and it is safe to use them for autoimmune diseases, rheumatoid arthritis, systemic lupus erythematosus and malaria as well. Determination of CQ, HCQ and their metabolites in biologic fluids and in pharmaceuticals has great importance, especially for pharmacokinetics, pharmacodynamics and epidemiological studies. In this review, liquid chromatographic methods developed in the last 10 years were summarized focusing on sample preparation and detection methods for HCQ and CQ determination in biological fluids and pharmaceutical preparations. It is hoped that this article could be helpful to facilitate the use of these drugs in clinical trials or drug research studies as it provides comprehensive information on the reported analytical methods.

Cloud Point Extraction in the Determination of Drugs in Biological Matrices

Cloud point extraction (CPE) is a simple, safe and environment-friendly technique used in the preparation of various samples. It was primarily developed for the assessment of environmental samples, especially analyzed for metals. Recently, this technique has been used in the extraction and determination of various chemical compounds (e.g., drugs, pesticides and vitamins), in various matrices (e.g., human plasma, human serum, milk and urine). In this review, we show that CPE is a reliable method of extraction and can be used in analytical laboratories in combination with other techniques that can be used in the determination of drugs and other chemicals in the human biological matrix. According to the literature, a combination of different methods provides good recovery and can be used in the simultaneous determination of many drugs in a single analysis. CPE can be optimized by changing its conditions (e.g., type of surfactant used, incubation temperature, pH and the addition of salts). In this review, we present the optimized CPE methods used in the determination of various pharmaceuticals and describe how the conditions affect the performance of extraction. This data might support future designing of the new CPE applications that are simple and more accurate. We compared CPE with other extraction methods and also showed the advantages and disadvantages of various extraction techniques along with a discussion on their environmental impact. According to the publications reviewed, it is obvious that CPE is an easy, safe, rapid and inexpensive method of extraction.

High-throughput screening for high-efficiency small-molecule biosynthesis

Systems metabolic engineering faces the formidable task of rewiring microbial metabolism to cost-effectively generate high-value molecules from a variety of inexpensive feedstocks for many different applications. Because these cellular systems are still too complex to model accurately, vast collections of engineered organism variants must be systematically created and evaluated through an enormous trial-and-error process in order to identify a manufacturing-ready strain. The high-throughput screening of strains to optimize their scalable manufacturing potential requires execution of many carefully controlled, parallel, miniature fermentations, followed by high-precision analysis of the resulting complex mixtures. This review discusses strategies for the design of high-throughput, small-scale fermentation models to predict improved strain performance at large commercial scale. Established and promising approaches from industrial and academic groups are presented for both cell culture and analysis, with primary focus on microplate- and microfluidics-based screening systems.

Coupling Droplet Microfluidics with Mass Spectrometry for Ultrahigh-Throughput Analysis of Complex Mixtures up to and above 30 Hz

High- and ultrahigh-throughput label-free sample analysis is required by many applications, extending from environmental monitoring to drug discovery and industrial biotechnology. HTS methods predominantly are based on a targeted workflow, which can limit their scope. Mass spectrometry readily provides chemical identity and abundance for complex mixtures, and here, we use microdroplet generation microfluidics to supply picoliter aliquots for analysis at rates up to and including 33 Hz. This is demonstrated for small molecules, peptides, and proteins up to 66 kDa on three commercially available mass spectrometers from salty solutions to mimic cellular environments. Designs for chip-based interfaces that permit this coupling are presented, and the merits and challenges of these interfaces are discussed. On an Orbitrap platform droplet infusion rates of 6 Hz are used for analysis of cytochrome c, on a DTIMS Q-TOF similar rates were obtained, and on a TWIMS Q-TOF utilizing IM-MS software rates up to 33 Hz are demonstrated. The potential of this approach is demonstrated with proof of concept experiments on crude mixtures including egg white, unpurified recombinant protein, and a biotransformation supernatant.

Stable biphasic interfaces for open microfluidic platforms

We present an open microfluidic platform that enables stable flow of an organic solvent over an aqueous solution. The device features apertures connecting a lower aqueous channel to an upper solvent compartment that is open to air, enabling easy removal of the solvent for analysis. We have previously shown that related open biphasic systems enable steroid hormone extraction from human cells in microscale culture and secondary metabolite extraction from microbial culture; here we build on our prior work by determining conditions under which the system can be used with extraction solvents of ranging polarities, a critical feature for applying this extraction platform to diverse classes of metabolites. We developed an analytical model that predicts the limits of stable aqueous-organic interfaces based on analysis of Laplace pressure. With this analytical model and experimental testing, we developed generalized design rules for creating stable open microfluidic biphasic systems with solvents of varying densities, aqueous-organic interfacial tensions, and polarities. The stable biphasic interfaces afforded by this device will enable on-chip extraction of diverse metabolite structures and novel applications in microscale biphasic chemical reactions.

High throughput screening of complex biological samples with mass spectrometry – from bulk measurements to single cell analysis

We review the state of the art in HTS using mass spectrometry with minimal sample preparation from complex biological matrices. We focus on industrial and biotechnological applications.

Dilution Effect in Multichannel Liquid-Handling System Equipped with Fixed Tips: Problems and Solutions for Bioanalytical Sample Preparation

This paper presents an in-depth investigation of the dilution effect from the liquid handlers equipped with fixed tips resulting from mixing with residues of the system liquid used to wash the inside and outside of the fixed tips. The impact of the dilution in bioanalytical sample preparation was evaluated. The liquid-transfer steps, where the dilution effect should be minimized or eliminated in bioanalytical sample preparation, were the sample dilution, and the standard (STD) and quality control (QC) sample preparation steps. The level of the dilution effect for the red dye was quantified by using the dual-dye photometric measurement. A significant dilution effect was observed for the red dye, indicating that without a proper liquid-transfer strategy to minimize it, it would be impossible to prepare serially diluted STD and QC samples because of the cumulative dilution effect. The impact on the bioanalytical results was substantial, especially when a multistep dilution scheme was used for the sample dilutions. A unique liquid-transfer strategy was designed in our lab to minimize the dilution effect for the sample dilution. The effectiveness of this strategy was demonstrated using the dual-dye photometric measurement and by generating a successful STD curve preparation of a model compound, Compound A, in dog plasma for an LC/MS/MS assay. With this strategy, high-quality bioanalytical sample preparation without the dilution effect could be achieved by using the liquid handlers equipped with fixed tips.

High throughput screening of particle conditioning operations: II. Evaluation of scale-up heuristics with prokaryotically expressed polysaccharide vaccines

Multivalent polysaccharide conjugate vaccines are typically comprised of several different polysaccharides produced with distinct and complex production processes. Particle conditioning steps, such as precipitation and flocculation, may be used to aid the recovery and purification of such microbial vaccine products. An ultra scale-down approach to purify vaccine polysaccharides at the micro-scale would greatly enhance productivity, robustness, and speed the development of novel conjugate vaccines. In part one of this series, we described a modular and high throughput approach to develop particle conditioning processes (HTPC) for biologicals that combines flocculation, solids removal, and streamlined analytics. In this second part of the series, we applied HTPC to industrially relevant feedstreams comprised of capsular polysaccharides (CPS) from several bacterial species. The scalability of HTPC was evaluated between 0.8 mL and 13 L scales, with several different scaling methodologies examined. Clarification, polysaccharide yield, impurity clearance, and product quality achieved with HTPC were reproducible and comparable with larger scales. Particle sizing was the response with greatest sensitivity to differences in processing scale and enabled the identification of useful scaling rules. Scaling with constant impeller tip speed or power per volume in the impeller swept zone offered the most accurate scale up, with evidence that time integration of these values provided the optimal basis for scaling. The capability to develop a process at the micro-scale combined with evidence-based scaling metrics provide a significant advance for purification process development of vaccine processes. The USD system offers similar opportunities for HTPC of proteins and other complex biological molecules.

Phylum-wide general protein O-glycosylation system of the Bacteroidetes

The human gut symbiont Bacteroides fragilis has a general protein O-glycosylation system in which numerous extracytoplasmic proteins are glycosylated at a three amino acid motif. In B. fragilis, protein glycosylation is a fundamental and essential property as mutants with protein glycosylation defects have impaired growth and are unable to competitively colonize the mammalian intestine. In this study, we analysed the phenotype of B. fragilis mutants with defective protein glycosylation and found that the glycan added to proteins is comprised of a core glycan and an outer glycan. The genetic region encoding proteins for the synthesis of the outer glycan is conserved within a Bacteroides species but divergent between species. Unlike the outer glycan, an antiserum raised to the core glycan reacted with all Bacteroidetes species tested, from all four classes of the phylum. We found that diverse Bacteroidetes species synthesize numerous glycoproteins and glycosylate proteins at the same three amino acid motif. The wide-spread conservation of this protein glycosylation system within the phylum suggests that this system of post-translational protein modification evolved early, before the divergence of the four classes of Bacteroidetes, and has been maintained due to its physiological importance to the diverse species of this phylum.

A new approach for antibiotic drugs determination in human plasma by liquid chromatography-mass spectrometry

Sensitive and selective analytical procedures based on high performance liquid chromatography with mass spectrometric detection were developed for the determination of linezolid (LIN) and amoxicillin (AMOX) in human plasma samples. Samples were prepared by applying protein precipitation (PP), solid phase extraction (SPE), and microextraction in packed syringe (MEPS). The analytical separation was carried out using reversed phase liquid chromatography in isocratic mode. All analytes were monitored by mass spectrometry (MS) detection in the product ion mode and the method was validated covering the corresponding therapeutic range of 1-30 μg/mL and 1-50 μg/mL for LIN and AMOX respectively. The assay was linear over AMOX and LIN concentration ranges. The method provided good validation data: accuracy (102.9% (LIN), 100.9% (AMOX)), limit of detection (0.1407 ng/mL (LIN); 0.1341 ng/mL (AMOX); quantification (0.3814 ng/mL (LIN), 0.4249 ng/mL (AMOX)) and acceptable stability within 24h in the auto-sampler. Three different methods were compared as regards precision, accuracy, recovery and matrix effects. The proposed methods offer a fast and simple way to determine selected antibiotic drugs in human plasma that could be applied in pharmacokinetic studies.

Supported liquid extraction offers improved sample preparation for aldosterone analysis by liquid chromatography tandem mass spectrometry

Background

To evaluate the accuracy and precision of a method for serum aldosterone using supported liquid extraction (SLE) for sample preparation instead of the more conventional liquid-liquid extraction (LLE) approach.

Methods

Two independently developed SLE-based LC-MS/MS methods for serum aldosterone (sample volumes 250 μl and 300 μl respectively) were compared to a modification of a previously reported LLE approach (sample volume 500 μl) in two method comparisons (n=75 and n=97). SLE analyses were performed at two separate centres. Precision was evaluated at a single site using human pools in head-to-head comparison between SLE and LLE. All analyses were performed on the ABSCIEX API-5000 LC-MS/MS system.

Results

At four increasing pool concentrations spanning 67-1060 pmol/l, total precision for SLE ranged from 6.8-4.1% compared with 11.1-4.3% for LLE. Differences did not reach statistical significance except at the lowest concentration where SLE was superior. Pasing Bablok regression comparisons were SLE=0.96×LLE-5.8 pmol/l (R2=0.985) and SLE=0.96×LLE-0.44 pmol/l (R2=0.969).

Conclusions

For analysis of serum aldosterone on the ABSCIEX API-5000, SLE affords a smaller sample volume while maintaining the accuracy and precision performance of LLE. By avoiding specimen vortexing, SLE also allows for greater automation in the sample preparation.

MARS: bringing the automation of small-molecule bioanalytical sample preparations to a new frontier

Background: In recent years, there has been a growing interest in automating small-molecule bioanalytical sample preparations specifically using the Hamilton MicroLab® STAR liquid-handling platform. In the most extensive work reported thus far, multiple small-molecule sample preparation assay types (protein precipitation extraction, SPE and liquid–liquid extraction) have been integrated into a suite that is composed of graphical user interfaces and Hamilton scripts. Using that suite, bioanalytical scientists have been able to automate various sample preparation methods to a great extent. However, there are still areas that could benefit from further automation, specifically, the full integration of analytical standard and QC sample preparation with study sample extraction in one continuous run, real-time 2D barcode scanning on the Hamilton deck and direct Laboratory Information Management System database connectivity. Results: We developed a new small-molecule sample-preparation automation system that improves in all of the aforementioned areas. Conclusion: The improved system presented herein further streamlines the bioanalytical workflow, simplifies batch run design, reduces analyst intervention and eliminates sample-handling error.

Recent development in software and automation tools for high-throughput discovery bioanalysis

Bioanalysis with LC–MS/MS has been established as the method of choice for quantitative determination of drug candidates in biological matrices in drug discovery and development. The LC–MS/MS bioanalytical support for drug discovery, especially for early discovery, often requires high-throughput (HT) analysis of large numbers of samples (hundreds to thousands per day) generated from many structurally diverse compounds (tens to hundreds per day) with a very quick turnaround time, in order to provide important activity and liability data to move discovery projects forward. Another important consideration for discovery bioanalysis is its fit-for-purpose quality requirement depending on the particular experiments being conducted at this stage, and it is usually not as stringent as those required in bioanalysis supporting drug development. These aforementioned attributes of HT discovery bioanalysis made it an ideal candidate for using software and automation tools to eliminate manual steps, remove bottlenecks, improve efficiency and reduce turnaround time while maintaining adequate quality. In this article we will review various recent developments that facilitate automation of individual bioanalytical procedures, such as sample preparation, MS/MS method development, sample analysis and data review, as well as fully integrated software tools that manage the entire bioanalytical workflow in HT discovery bioanalysis. In addition, software tools supporting the emerging high-resolution accurate MS bioanalytical approach are also discussed.

Rapid quantitative analysis of clarithromycin in rat plasma by UPLC-MS/MS after intravenous injection of the clarithromycin-loaded ultrafine PLGA nanoparticles

Nanoparticles were designed to encapsulate drugs to alter their pharmacological behaviors, therefore, it is very essential to monitor the pharmacokinetic profile of drug encapsulated in nanoparticles in order to clarify and predict their efficacy and side effects. In this paper, we reported a simple, rapid μ-elution 96-well solid phase extraction (μSPE) method combining with ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for determination of nanoformulated drug in rat plasma. This method presented satisfactory results in terms of sensitivity, precision, accuracy, and recovery, for the first time, of quantitatively analyzing clarithromycin (CLA) in rat plasma after intravenous administration CLA-loaded ultrafine PLGA nanoparticles for pharmacokinetic study. This method has been proved to be fast, reliable and reproducible to accurately analyze drug encapsulated in polymeric nanoparticles sample for a pharmacokinetic study.

Automated supported liquid extraction using 2D barcode processing for routine toxicokinetic portfolio support

Background: A new bioanalytical sample preparation approach has been developed to enhance the efficiency, reduce errors and improve the data quality supporting routine toxicokinetic (TK) study samples analysis, via the implementation of 2D barcode processing coupled with fully automated supported liquid extraction (SLE). Results: A fully automated SLE was validated and used to determine TK drug concentrations of over 500 unknown samples via 2D barcode processing. Assay performance calculated from a total of 291 quality control samples over the period of validation through sample analysis demonstrated inter-day precision and accuracy within 10 and 7.3%, respectively. Conclusion: A new logistical approach implementing the use of 2D barcodes and automated SLE demonstrates the potential of a new methodology for the routine bioanalytical support of TK study sample analysis.

Quantitative analysis of PD 0332991 in mouse plasma using automated micro-sample processing and microbore liquid chromatography coupled with tandem mass spectrometry

In the oncology therapeutic area, the mouse is the primary animal model used for efficacy studies. Often with mouse pharmacokinetic (PK) and pharmacokinetic/pharmacodynamic (PK/PD) studies, less than 20 μL of total plasma sample volume is available for bioanalysis due to the small size of the animal and the need to split samples for other measurements such as biomarker analyses. The need to conduct automated "small volume" sample processing for quantitative bioanalysis has therefore increased. An automated fit for purpose protein precipitation (PPT) method using a Hamilton MicroLab Star (Reno, NV, USA) to support mouse PK and PK/PD studies for an oncology drug candidate PD 0332991, (a specific inhibitor of cyclin-dependent kinase 4 (CDK-4) currently in development) for processing "small volumes" was developed. The automated PPT method was achieved by extracting and processing 10 μL out of a minimum sample volume of 15 μL plasma utilizing the Hamilton MicroLab Star. A 96-conical shallow well plate by Agilent Technologies, Inc (Wilmington, DE, USA) was the labware of choice used in the automated Hamilton "small volume" method platform. Analyses of a 10 μL plasma aliquot from 15 μL of plasma study samples were conducted by both automated and manual PPT method. All plasma samples were quantitated using a Sciex API 4000 triple quadrupole mass spectrometer coupled with an Eksigent Express HT Ultra HPLC system. The chromatography was achieved using an Agilent microbore C(18) Extend, 1.0 × 50 mm, 3.5 μm column at a flow rate of 0.150 mL/min with a total run time of 1.8 min. Accuracy and precision of standard and QC concentration levels were within 90-107% and <14%, respectively. Calibration curves were linear over the dynamic range of 1.0-1000 ng/mL. PK studies for PD 0332991 were conducted in female C3H mice following intravenous administration at 1mg/kg and oral administration at 2mg/kg. PK values such as area under curve (AUC), volume of distribution (Vd), clearance (Cl), half life (T(1/2)) and bioavailability (F%) demonstrated less than 11% difference between the automated Hamilton and manual PPT methods. The results demonstrate that the automated Hamilton PPT method can accurately and precisely aliquot 10 μL of plasma from 15 μL or larger volume plasma samples. The fit for purpose Hamilton PPT method is suitable for routine analyses of plasma samples from micro-sampling PK and PK/PD samples to support discovery studies.

Fast liquid chromatography combined with mass spectrometry for the analysis of metabolites and proteins in human body fluids

In the last decade various analytical strategies have been established to enhance separation speed and efficiency in high performance liquid chromatography applications. Chromatographic supports based on monolithic material, small porous particles, and porous layer beads have been developed and commercialized to improve throughput and separation efficiency. This paper provides an overview of current developments in fast chromatography combined with mass spectrometry for the analysis of metabolites and proteins in clinical applications. Advances and limitations of fast chromatography for the combination with mass spectrometry are discussed. Practical aspects of, recent developments in, and the present status of high-throughput analysis of human body fluids for therapeutic drug monitoring, toxicology, clinical metabolomics, and proteomics are presented.

Recent progress in microchip electrophoresis-mass spectrometry

This review highlights the methodological and instrumental developments in microchip electrophoresis (MCE)-mass spectrometry (MS) from 1997. In MCE-MS, the development of ionization interface is one of the most important issues to realize highly sensitive detection and high separation efficiency. Among several interfaces, electrospray ionization (ESI) has been mainly employed to MCE-MS since a simple structure of the ESI interface is suitable for coupling with the microchips. Although the number of publications is still limited, laser desorption ionization (LDI) interface has also been developed for MCE-MS. The characteristics of the ESI and LDI interfaces applied to the electrophoresis microchips are presented in this review. The scope of applications in MCE-MS covers mainly biogenic compounds such as bioactive amines, peptides, tryptic digests and proteins. This review provides a comprehensive table listing the applications in MCE-MS.

Automated sample preparation for regulated bioanalysis: an integrated multiple assay extraction platform using robotic liquid handling

Background: A novel approach for regulated bioanalytical sample preparation has been developed to combine multiple types of extraction techniques into one integrated and automated sample-preparation suite that pairs a graphical user interface with the Hamilton Microlab® STAR robotic liquid handler. Results: The multi-assay sample-preparation suite is composed of three bioanalytical extraction techniques: protein precipitation, solid-phase extraction and liquid–liquid extraction. Validation data provided highly reproducible and robust results for each respective automated extraction technique. Conclusion: The user-friendly graphical user interface and modular method design provide a flexible and versatile approach for routine bioanalytical sample-preparation and is the first fully integrated multiple assay sample-preparation suite for regulated bioanalysis.

Automatic Supported Liquid Extraction (SLE) Coupled with HILIC-MS/MS: An Application to Method Development and Validation of Erlotinib in Human Plasma

A novel bioanalytical method was developed and validated for the quantitative determination of erlotinib in human plasma by using the supported liquid extraction (SLE) sample cleanup coupled with hydrophilic interaction liquid chromatography and tandem mass spectrometric detection (HILIC-MS/MS). The SLE extract could be directly injected into the HILIC-MS/MS system for analysis without the solvent evaporation and reconstitution steps. Therefore, the method is simple and rapid. In the present method, erlotinib-d₆ was used as the internal standard. The SLE extraction recovery was 101.3%. The validated linear curve range was 2 to 2,000 ng/mL based on a sample volume of 0.100-mL, with a linear correlation coefficient of > 0.999. The validation results demonstrated that the present method gave a satisfactory precision and accuracy: intra-day CV < 5.9% (.

Use of solid-supported liquid-liquid extraction in the analysis of polyphenols in wine

Solid-supported liquid-liquid extraction (SS-LLE) was compared to liquid-liquid extraction (LLE) for the analysis of phenolic compounds in wine. Diatomaceous earth commercial cartridges were evaluated together with "in-house" made cartridges for the wine phenolic extraction. Statistical treatment, analysis of variance ANOVA-single factor, was used to compare the extraction yields obtained by these methods, and for the majority of the studied compounds, significantly higher yields were obtained by the SS-LLE methodology using the "in-house" prepared cartridges. This is an environmentally friendly low-cost sample preparation method which proved to be reproducible (RSD<5% for the most compounds) and yielding high recoveries (80-100%) for the compounds studied.

Recent developments in extraction procedures relevant to analytical toxicology

Sample preparation is an important step in the development of an analytical method but is often regarded as time-consuming, laborious work. Optimum sample preparation leads to enhanced selectivity and sensitivity, however, and reduces amounts of interfering matrix compounds, resulting in less signal suppression or enhancement. Recent developments in extraction techniques that could be of interest in clinical and forensic toxicology, for example liquid-liquid, solid-phase, and headspace extraction, are summarized in this review. The advantages and disadvantages of several extraction techniques are discussed, to enable the reader to choose an appropriate method of extraction for his or her application. Attention is paid to current trends in analytical toxicology, for example miniaturization, high throughput, and automation.

A hierarchical screening methodology for physicochemical/ADME/Tox profiling

Full integration of pharmaceutical profiling into pharmaceutical lead selection and optimisation requires that complete sets of unequivocal data be available at the time compound design or advancement decisions are made. As the productivity of chemical synthesis expands, and the breadth of profiling assays grow in scope, physicochemical/ADME/Tox laboratories are being challenged to produce ever more data to support an accelerating decision cycle. This article focuses on the challenges of increasing preclinical profiling productivity while managing lower accuracy higher throughput data streams to preserve confidence in decision making. The authors propose a hierarchical screening strategy and describe the implementation of an automated system designed to support that strategy efficiently.

Liquid chromatography-mass spectrometry for the quantitative bioanalysis of anticancer drugs

The monitoring of anticancer drugs in biological fluids and tissues is important during both pre-clinical and clinical development and often in routine clinical use. Traditionally, liquid chromatography (LC) in combination with ultraviolet (UV), fluorescence, or electrochemical detection is employed for this purpose. The successful hyphenation of LC and mass spectrometry (MS), however, has dramatically changed this. MS detection provides better sensitivity and selectivity than UV detection and, in addition, is applicable to a significantly larger group of compounds than fluorescence or electrochemical detection. Therefore, LC-MS has now become the method of first choice for the quantitative bioanalysis of many anticancer agents. There are still, however, a lot of new developments to be expected in this area, such as the introduction of more sensitive and robust mass spectrometers, high-throughput analyses, and further optimization of the coupled LC systems. Many articles have appeared in this field in recent years and are reviewed here. We conclude that LC-MS is an extremely powerful tool for the quantitative analysis of anticancer drugs in biological samples.

Automation and robotics in ADME screening

The use of automated sample processing, analytics and screening technology for profiling absorption, distribution, metabolism and excretion (ADME) and physicochemical properties, early in the drug discovery process, is becoming more widespread. The use and application of these technologies is both diverse and innovative. High-throughput screening (HTS) technologies have been utilised enabling the profiling of an increased number of compounds emerging from the drug discovery process. Although the drivers for using these technologies are common, different approaches can be taken.:

96-Well liquid–liquid extraction liquid chromatography-tandem mass spectrometry method for the quantitative determination of ABT-578 in human blood samples

We report here a quantitative method for the analysis of ABT-578 in human whole blood samples. Sample preparation was achieved by a semi-automated 96-well format liquid-liquid extraction (LLE) method. Aluminum/polypropylene heat seal foil was used to enclose each well of the 96-well plate for the liquid-liquid extraction. A liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) method with pre-column regeneration was developed for the analysis of sample extracts. Selective reaction monitoring (SRM) of the mass transitions m/z 983-935 and m/z 931-883 was employed for the detection of ABT-578 and internal standard, respectively. The ammonium adduct ions [M + NH(4)](+) generated from electrospray ionization were monitored as the precursor ions. The assay was validated for a linear dynamic range of 0.20-200.75ng/ml. The correlation coefficient (r) was between 0.9959 and 0.9971. The intra-assay CV (%) was between 1.9 and 13.5% and the inter-assay CV (%) was between 4.7 and 11.3%. The inter-assay mean accuracy was between 86.4 and 102.5% of the theoretical concentrations.

Liquid chromatography–negative ion electrospray tandem mass spectrometry method for the quantification of tacrolimus in human plasma and its bioanalytical applications

A simple, rapid, novel and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of tacrolimus (I) in human plasma, a narrow therapeutic index, potent macrolide immunosuppressive drug. The analyte and internal standard (tamsulosin (II)) were extracted by liquid-liquid extraction with t-butylmethylether using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on reverse phase Xterra ODS column with a mobile phase of 99% methanol and 1% 10mM ammonium acetate buffer. The deprotonate of analyte was quantitated in negative ionization by multiple reaction monitoring (MRM) with a mass spectrometer. The mass transitions m/z 802.5-->560.3 and m/z 407.2-->151.9 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.05-25ng/ml for tacrolimus in human plasma. The lower limit of quantitation was 50pg/ml with a relative standard deviation of less than 20%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. Run time of 2min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in comparative bioavailability studies. The tacrolimus plasma concentration profile could be obtained for pharmacokinetic study. The observed maximum plasma concentration (C(max)) of tacrolimus (5mg oral dose) is 440pg/ml, time to observed maximum plasma concentration (T(max)) is 2.5h and elimination half-life (T(1/2)) is 21h.

High-throughput pharmacokinetics screen of VLA-4 antagonists by LC/MS/MS coupled with automated solid-phase extraction sample preparation

Automation of plasma sample preparation for pharmacokinetic studies on VLA-4 antagonists has been achieved by using 96-well format solid-phase extraction operated by Beckman Coulter Biomek 2000 liquid handling system. A Biomek 2000 robot is used to perform fully automated plasma sample preparation tasks that include serial dilution of standard solutions, pipetting plasma samples, addition of standard and internal standard solutions, performing solid-phase extraction (SPE) on Waters OASIS 96-well plates. This automated sample preparation process takes less than 2 h for a typical pharmacokinetic study, including 51 samples, 24 standards, 9 quality controls, and 3-6 dose checks with minimal manual intervention. Extensive validation has been made to ensure the accuracy and reliability of this method. A two-stage vacuum pressure controller has been incorporated in the program to improve SPE efficiency. This automated SPE sample preparation approach combined with liquid chromatography coupled with the high sensitivity and selectivity of tandem mass spectrometry (LC/MS)/MS has been successfully applied on both individual and cassette dosing for pharmacokinetic screening of a large number of VLA-4 antagonists with a limit of quantitation in the range of 1-5 ng/ml. Consequently, a significant throughput increase has been achieved along with an elimination of tedious labor and its consequential tendency to produce errors.

Automated high throughput ADME assays for metabolic stability and cytochrome P450 inhibition profiling of combinatorial libraries

Early determinations of pharmaceutical properties can serve as predictors of a compound's likely development success. Our laboratory has implemented high throughput in vitro absorption, distribution, metabolism and excretion (ADME) assays which address absorption, metabolism, and physico-chemical properties in an effort to identify potential development liabilities early, thereby minimizing discovery to market attrition. In response to the throughput demands of parallel synthesis, we have incorporated a SAGIAN core robotics system for the determination of both metabolic stability in human liver microsomes (HLMs) and cytochrome P450 (CYP450) inhibition. This automated solution has led to an increase in capacity, throughput and reliability for both in vitro assays. The SAGIAN core robotics system integrates devices such as liquid handlers, plate hotels and incubators through the use of an ORCA robotic arm. The HLM stability assay utilizes a Multimek 96-channel pipettor for liquid handling. The incubation plates are transferred off-line for final semi-quantitative analysis using high throughput parallel LC/MS. The CYP inhibition method combines both liquid handlers and an integrated fluorescence plate reader to perform single concentration percent inhibition assays for 88 compounds. Cytochrome P450 inhibition is measured for both CYP3A4 and CYP2D6 isozymes. This system represents a fully integrated approach to high throughput ADME evaluation in support of drug discovery. The core system concept creates a plug-and-play approach, which combines a series of modular stations to build a robotic platform, which is flexible, upgradable, and easily reconfigured when assays change or are newly developed. The application of these strategies as a means of assessing metabolic stability and CYP inhibition of synthetic libraries is discussed.

Feasibility of an on-line restricted access material/liquid chromatography/tandem mass spectrometry method in the rapid and sensitive determination of organophosphorus triesters in human blood plasma

A rapid on-line solid phase extraction/liquid chromatography/tandem mass spectrometry (SPE/LC/MS/MS) method using restricted access material (RAM) was developed for the simultaneous determination of eight organophosphorus triesters in untreated human blood plasma. In a process involving column-switching techniques, the analytes were enriched on the RAM column, separated using a C-18 analytical column and detected with LC/MS. Tandem mass spectrometry was used to characterize and quantify the analytes. To elucidate the fragmentation pathway of a number of the analytes, MS3 experiments using an ion trap mass spectrometer were performed. The matrix effects associated with using APCI and ESI interfaces were investigated. The recoveries obtained were in the range 60-92% (R.S.D.<6%), with estimated detection limits between 0.2 and 1.8 ng/ml of plasma, and the total analysis time was 27 min.