Strategy of Accelerated Method Development for High-Throughput Bioanalytical Assays Using Ultra High-Performance Liquid Chromatography Coupled with Mass Spectrometry

An Update on Current Trend in Sample Preparation Automation in Bioanalysis: strategies, Challenges and Future Direction

Automation in sample preparation improves accuracy, productivity, and precision in bioanalysis. Moreover, it reduces resource consumption for repetitive procedures. Automated sample analysis allows uninterrupted handling of large volumes of biological samples originating from preclinical and clinical studies. Automation significantly helps in management of complex testing methods where generation of large volumes of data is required for process monitoring. Compared to traditional sample preparation processes, automated procedures reduce associated expenses and manual error, facilitate laboratory transfers, enhance data quality, and better protect the health of analysts. Automated sample preparation techniques based on robotics potentially increase the throughput of bioanalytical laboratories. Robotic liquid handler, an automated sample preparation system built on a robotic technique ensures optimal laboratory output while saving expensive solvents, manpower, and time. Nowadays, most of the traditional extraction processes are being automated using several formats of online techniques. This review covered most of the automated sample preparation techniques reported till date, which accelerated and simplified the sample preparation procedure for bioanalytical sample analysis. This article critically analyzed different developmental aspects of automated sample preparation techniques based on robotics as well as conventional sample preparation methods that are accelerated using automated technologies.

Determination of Pralsetinib in Human Plasma and Cerebrospinal Fluid for Therapeutic Drug Monitoring by Ultra-performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS)

BACKGROUND

Ultra-performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS) is widely used for concentration detection of many Tyrosine Kinase Inhibitors (TKIs), including afatinib, crizotinib, and osimertinib. In order to analyze whether pralsetinib takes effect in Rearranged during Transfection (RET)-positive patients with central nervous system metastasis, we aimed to develop a method for the detection of pralsetinib concentrations in human plasma and Cerebrospinal Fluid (CSF) by UPLC-MS/MS.

METHODS

The method was developed using the external standard method, and method validation included precision, accuracy, stability, extraction recovery, and matrix effect. Working solutions were all obtained based on stock solutions of pralsetinib of 1mg/mL. The plasma/CSF samples were precipitated by acetonitrile for protein precipitation and then separated on an ACQUITY UPLC HSS T3 column (2.1×100 mm, 1.8 μm) with a gradient elution using 0.1% formic acid (solution A) and acetonitrile (solution B) as mobile phases at a flow rate of 0.4 mL/min. The tandem mass spectrometry was performed by a triple quadrupole linear ion trap mass spectrometry system (QTRAPTM 6500+) with an electrospray ion (ESI) source and Analyst 1.7.2 data acquisition system. Data were collected in Multiple Reaction Monitoring (MRM) and positive ionization mode.

RESULTS

A good linear relationship of pralsetinib in both plasma and CSF was successfully established, and the calibration ranges were found to be 1.0-64.0 μg/mL and 50.0ng/mL-12.8 μg/mL for pralsetinib in the plasma and CSF, respectively. Validation was performed, including calibration assessment, selectivity, precision, accuracy, matrix effect, extraction recovery, and stability, and all results have been found to be acceptable. The method has been successfully applied to pralsetinib concentration detection in a clinical sample, and the concentrations have been found to be 475 ng/mL and 61.55 μg/mL in the CSF and plasma, respectively.

CONCLUSION

We have developed a quick and effective method for concentration detection in both plasma and CSF, and it can be applied for drug monitoring in clinical practice. The method can also provide a reference for further optimization.

Non-regulated LC-MS/MS bioanalysis in support of early drug development - a Novartis perspective

Scientifically qualified LC-MS/MS methods are essential for the determination of small molecule drug candidates and/or their metabolite(s) in support of various non-regulated safety assessment and in vivo absorption, distribution, metabolism and excretion studies in preclinical development. This article outlines an effective method development workflow to fit for this purpose. The workflow features a 'universal' protein precipitation solvent for efficient sample extraction, a mobile phase additive for managing chromatographic resolution and addressing carryover and an internal standard cocktail to select the best analogue internal standard to track the analyte of interest in LC-MS/MS. In addition, good practices are recommended to prevent bioanalytical pitfalls due to instability, non-specific binding and dosing vehicle-induced matrix effect. Proper handling of non-liquid matrix is also discussed.

LC-MS/MS assay for the determination of tat-K13, a novel interfering peptide for the treatment of ischemic stroke, in human plasma and its application to a pharmacokinetics study

A sensitive and robust method has been developed using an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay to quantify Tat-K13, a novel interfering peptide for the treatment of ischemic stroke, in human plasma. Automated solid-phase extraction on a Waters Oasis WCX (30 μm, 10 mg) 96-well plate was used to extract Tat-K13 from human plasma and the extracts were separated on a Waters Acquity CSH column (2.1 × 50 mm i.d., 1.7 μm) with a gradient elution method by mobile phase A (nonafluoropentanoic acid-acetic acid-water, 1:2:1000, v/v/v) and B (nonafluoropentanoic acid-acetic acid-water-acetonitrile, 1:2:100:900, v/v/v/v). The method was fully validated following international bioanalytical guidelines and showed good linearity from 2.10 to 1,050 ng/ml. The method was successfully applied to investigate the clinical pharmacokinetics of Tat-K13 in health volunteers. Rapid elimination of Tat-K13 from the body was observed, with half-life ranging from 0.26 to 0.78 h across different dose levels. The exposure of Tat-K13 was approximately dose-dependent in terms of the area under the concentration-time curve and peak concentration.

Development and validation of a UPLC-MS/MS method for quantification of C-005, a novel third-generation EGFR TKI, and its major metabolite in plasma: Application to its first-in-patient study

C-005 is a novel third-generation EGFR tyrosine kinase inhibitor for the treatment of non-small cell lung cancer (NSCLC). To support its clinical trial, we developed a rapid and sensitive bioanalytical method based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) technique for the quantification of C-005 and its major metabolite in NSCLC patients following international bioanalytical guidelines. After a simple and quick protein precipitation step, the supernatant was injected to a Waters Acquity BEH C₁₈ column (2.1 × 50 mm i.d., 1.7 mm), and the column was eluted with a gradient of buffer A (5 mM ammonium acetate and 0.1% formic acid in water) and buffer B (formic acid-acetonitrile (1:1000, v/v)). The eluates were subsequently detected by an AB QTRAP 5500 mass spectrometer with electrospray ionization using multiple-reaction monitoring mode. The method showed good linearity from 2.00 to 1000 ng/mL for C-005 and 1.00 to 500 ng/mL for M1. In conclusion, the validation results demonstrated the robustness of the method and its well-poised to support the first-in-patient study of C-005 in NSCLC patients.

UHPLC-MS/MS method to determine FP-208 in human plasma and its application to a pharmacokinetic study

Aim: FP-208 is a novel and effective small-molecule inhibitor blocking the mammalian target of rapamycin complex-1/mammalian target of rapamycin complex-2/PI3Ka. To investigate the pharmacokinetic profile of FP-208, a rapid and reliable analytical method was needed to be established to determine FP-208 in the plasma of patients with solid tumors. Materials & methods: FP208 was separated on a charged surface hybrid (CSH) C18 column (2.1 mm × 50 mm, 1.7 μm) after the plasma samples were purified using a protein precipitation method. Detection was performed on an AB Sciex 5500 mass spectrometer in the positive electrospray ionization mode. The established method was validated according to the bioanalytical guidelines. Conclusion: For the first time, the developed and validated method was successfully applied in the first-in-human study for FP-208 in patients with solid tumors after oral administration (Number: CTR20180683).

CX1003 quantification by ultra-performance LC-MS/MS in human plasma and its application to a pharmacokinetic study in solid tumor patients

Aim: CX1003 is a novel multitargeted receptor tyrosine kinase inhibitor targeting cancer patients with relapsed or metastatic malignant solid tumors. The study aimed to develop a robust and rapid assay approach to quantify CX1003 in human plasma. Methodology & results: Samples of plasma were purified by SPE where the diluted eluates were then separated by a Waters Acquity CSH C₁₈ column and thereafter detected using positive electrospray ionization via an ultra performance LC-MS/MS. Conclusion: The method to quantify CX1003 in human plasma was first exploited and validated with good sensitivity and specificity, and successfully fulfilled the requirement of the first-in-human clinical pharmacokinetic study of CX1003 in Chinese patients with relapsed or metastatic malignant solid tumors.

An ultra HPLC-MS/MS method for quantification of hypidone hydrochloride (YL-0919) and application to a pharmacokinetic study

Aim: Hypidone hydrochloride (YL-0919) was a novel combined selective serotonin reuptake inhibitor and 5-hydroxytryptamine receptor agonist for treatment of major depressive disorder. Quantitation of YL-0919 in plasma samples was critical for evaluation of its pharmacokinetics in clinical studies. Methodology & results: An ultra HPLC-MS/MS method has been developed and validated. Plasma samples were extracted by SPE method and then chromatographed on an Acquity BEH C₁₈ column. Detection was performed on an API-5500 tandem mass spectrometer using positive ESI. Conclusion: A sensitive and robust method was developed and validated for quantitative analysis of YL-0919 in human plasma samples for the first time. And this novel method was successfully applied to investigate pharmacokinetic profiles of YL-0919 in Chinese healthy subjects.

Simultaneous determination of FLZ and its metabolite (M1) in human plasma and urine by UHPLC-MS/MS: Application to a pharmacokinetic study

FLZ is a novel anti-Parkinson's disease candidate drug. The main active metabolite is FLZ O-dealkylation (M1) in preclinical studies. A reliable ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) quantitation method was developed for the simultaneous determination of FLZ and M1 with low limits of quantitation in human plasma (0.1 ng/mL) and urine (0.5 ng/mL). The plasma and urine samples were both purified by full-automatic solid phase extraction (SPE) method with ensured high extraction recovery and little matrix effect for both analytes, and then separated on a BEH C₁₈ column (2.1 × 50 mm, 1.7 μm). Detection and quantification were performed using an electrospray ionization (ESI) source in positive mode by multiple reaction monitoring (MRM). The precursor to product ion transitions were monitored at m/z 450.3⁺→313.2⁺ for FLZ, m/z 436.3⁺→299.1⁺ for M1, m/z 462.6⁺→142.0⁺ for [D₁₂]-FLZ (internal standard of FLZ) and m/z 447.2⁺→125.2⁺ for [D₁₁]-M1 (internal standard of M1), respectively. This method showed good linearity, accuracy, precision and stability in the range of 0.1-100 ng/mL in plasma and 0.5-500 ng/mL in urine of two analytes. Finally, the developed method was successfully applied to a pharmacokinetic research in Chinese healthy volunteers after oral administration of FLZ tablets.

Practical strategies when using a stable isotope labeled microtracer for absolute bioavailability assessment: A case study of a high oral dose clinical candidate GDC-0810

The pH labile metabolite, hydrophobicity, high oral dose and systematic exposure of GDC-0810 posed tremendous challenges to develop a LC-MS method for a stable isotope labeled aBA study. In this study, we explored practical solutions to balance stability and sensitivity and to cope with the impact of high C_p.o. to C_i.v. ratio on the labeling selection and assay dynamic range. A [¹³C₉] GDC-0810 was synthesized to minimize the isotopic interference between PO dose, internal standard and I.V. microtracer. A highly sensitive LC-MS assay was validated for quantitation of [¹³C₉] GDC-0810 from 5 to 1250 pg/mL. The optimized method was applied to a proof of concept cynomolgus monkey aBA study and the bioavailability calculated using microtracer dosing and regular dosing were similar to each other.

A UPLC-MS/MS method for quantification of 5α-androst-3β,5,6β-triol in human plasma: development, validation and its application in clinical pharmacokinetic study

AIM

5α-androst-3β,5,6β-triol is a novel ischemic stroke drug under clinical development. The objective of this study was to develop and validate a simple ultraperformance liquid chromatography tandem mass spectrometry method for 5α-androst-3β,5,6β-triol in human plasma and its application in clinical pharmacokinetic study. Methodology & results: After being pretreated using an automatized solid-phase extraction procedure, plasma sample was separated on a Waters^® Acquity™ BEH C₁₈ column (2.1 × 50 mm id, 1.7 mm) by an Acquity UPLC system and detected by an API 5500 triple quadrupole mass spectrometer, which was validated following international guidelines.

CONCLUSION

A simple method was successfully validated over a concentration range of 2.00-500 ng/ml for 5α-androst-3β,5,6β-triol and applied to investigate its plasma pharmacokinetic profiles in healthy Chinese subjects.

Development and validation of a UPLC-MS/MS method for simultaneous determination of fotagliptin and its two major metabolites in human plasma and urine

AIM

Fotagliptin is a novel dipeptidyl peptidase IV inhibitor under clinical development for the treatment of Type II diabetes mellitus. The objective of this study was to develop and validate a specific and sensitive ultra-performance liquid chromatography (UPLC)-MS/MS method for simultaneous determination of fotagliptin and its two major metabolites in human plasma and urine. Methodology & results: After being pretreated using an automatized procedure, the plasma and urine samples were separated and detected using a UPLC-ESI-MS/MS method, which was validated following the international guidelines.

CONCLUSION

A selective and sensitive UPLC-MS/MS method was first developed and validated for quantifying fotagliptin and its metabolite in human plasma and urine. The method was successfully applied to support the clinical study of fotagliptin in Chinese healthy subjects.

A simple, fast, sensitive and robust LC-MS/MS bioanalytical assay for evaluating 7α-hydroxy-4-cholesten-3-one biomarker in a clinical program

AIM

Serum 7α-hydroxy-cholesten-3-one (C4) has been reported as a biomarker to assess CYP7A1 enzyme activity and bile acid synthesis. To support a clinical program, a sensitive and reliable assay without derivatization was required for the analysis of C4 in human serum. Methodology & results: A systematic approach was used to optimize mass spectrometry, LC and sample extraction conditions, therefore, significantly improved assay sensitivity, and achieved the required quantification limit without derivatization. A surrogate matrix approach was used to overcome the interference from endogenous C4. A stable isotope-labeled C4 was used as internal standard. The samples were extracted using a simple protein precipitation method with 2% formic acid in acetonitrile.

CONCLUSION

A simple, fast, sensitive and robust UHPLC-MS/MS method for the quantification of 0.50 ng/ml C4 in 100 µl human serum was developed and fit for purpose validated. The method was successfully applied to the bioanalysis of C4 in a clinical study.

Investigation of the "true" extraction recovery of analytes from multiple types of tissues and its impact on tissue bioanalysis using two model compounds

LC-MS/MS has been widely applied to the quantitative analysis of tissue samples. However, one key remaining issue is that the extraction recovery of analyte from spiked tissue calibration standard and quality control samples (QCs) may not accurately represent the "true" recovery of analyte from incurred tissue samples. This may affect the accuracy of LC-MS/MS tissue bioanalysis. Here, we investigated whether the recovery determined using tissue QCs by LC-MS/MS can accurately represent the "true" recovery from incurred tissue samples using two model compounds: BMS-986104, a S1P₁ receptor modulator drug candidate, and its phosphate metabolite, BMS-986104-P. We first developed a novel acid and surfactant assisted protein precipitation method for the extraction of BMS-986104 and BMS-986104-P from rat tissues, and determined their recoveries using tissue QCs by LC-MS/MS. We then used radioactive incurred samples from rats dosed with ³H-labeled BMS-986104 to determine the absolute total radioactivity recovery in six different tissues. The recoveries determined using tissue QCs and incurred samples matched with each other very well. The results demonstrated that, in this assay, tissue QCs accurately represented the incurred tissue samples to determine the "true" recovery, and LC-MS/MS assay was accurate for tissue bioanalysis. Another aspect we investigated is how the tissue QCs should be prepared to better represent the incurred tissue samples. We compared two different QC preparation methods (analyte spiked in tissue homogenates or in intact tissues) and demonstrated that the two methods had no significant difference when a good sample preparation was in place. The developed assay showed excellent accuracy and precision, and was successfully applied to the quantitative determination of BMS-986104 and BMS-986104-P in tissues in a rat toxicology study.

Development and validation of a rapid and sensitive UPLC-MS/MS method for quantification of kukoamine B in human plasma: Application to a clinical pharmacokinetic study

A rapid, accurate and robust method was firstly developed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay to quantify kukoamine B, which is a novel drug under clinical development for the treatment of sepsis, in human plasma. Solid-phase extraction (SPE) was used to extract kukoamine B from human plasma. The extracts were separated on a Waters Acquity HSS T3 column (2.1×50mm i.d., 1.8μm) with a gradient elution method, using mobile phases of A (formic acid-water (1:1000, v/v)) and B(formic acid-methanol (1:1000, v/v)). Kukoamine B and internal standard (5-deuterated isotope kukoamine B) were detected under the multiple-reaction monitoring mode by an API 5500 triple quadrupole mass spectrometer with electrospray ionization. The method showed good linearity from 0.100 to 50.0ng/mL according to 1/x² weighted linear regression analysis. Inter- and intra-batch precision of kukoamine B were less than 15% and the accuracy was within 85-115%. The extraction recoveries and matrix effect of kukoamine B at three concentration levels were consistent. The sensitivity, specificity and stabilities under various conditions were validated. In conclusion, the validation results showed that this method was rapid, accurate, robust and can successfully fulfill the requirement of clinical pharmacokinetic study of kukoamine B mesylate in Chinese healthy subjects.

A simple, effective approach for rapid development of high-throughput and reliable LC-MS/MS bioanalytical assays

BACKGROUND

Rapidly developing LC-MS/MS assays with high-throughput and quality are challenging yet desired. Methodology & results: A simple method development approach was reported and demonstrated with the quantitative bioanalysis of BMS-984478, a hepatitis C virus nonstructural protein 5A inhibitor. An accurate, precise and robust LC-MS/MS method for the quantitation of BMS-984478 in rat and monkey plasma was developed and validated. Incurred sample reanalysis evaluation passed with 100% of samples meeting the acceptance criteria. The validated assay was successfully applied in toxicology studies without any failed runs.

CONCLUSION

The approach was successfully applied to the bioanalysis of BMS-984478 in toxicology and clinical studies. This approach was shown to be effective and reliable in speeding the development of high-throughput and reliable LC-MS/MS assays.

A highly sensitive and selective LC-MS/MS method to quantify asunaprevir, an HCV NS3 protease inhibitor, in human plasma in support of pharmacokinetic studies

Asunaprevir (BMS-650032) is a selective hepatitis C virus (HCV) NS3 protease inhibitor with potent activity against HCV genotypes 1, 4, 5 and 6. It has been developed in conjunction with direct-acting antiviral agents, in interferon- and ribavirin-free regimen, to improve existing therapies for HCV infection. To support the pharmacokinetic analyses in asunaprevir clinical studies, we have developed and validated a highly sensitive and robust LC-MS/MS method to quantify asunaprevir in human EDTA plasma with an LLOQ of 0.05ng/mL, which was a 20-fold sensitivity improvement over a previously reported assay for asunaprevir. A deuterated labeled [D9]-asunaprevir was used as the internal standard (IS). The analyte and the IS were extracted using a semi-automated liquid-liquid extraction (LLE) at pH 7 with methyl-t-butyl ether (MTBE) in a 96-well plate containing 10μL of 10% CHAPS as the surfactant to prevent non-specific binding issue. Chromatographic separation was achieved on a Genesis C8 column (2.1×50mm, 4μm) with a gradient elution using 0.1% formic acid in water as mobile phase A and a mixture of methanol: acetone: formic acid (95:5:0.1; v/v/v) as the mobile phase B. Positive electrospray ionization was performed using multiple reaction monitoring (MRM) with transitions of m/z 748→648 for asunaprevir and m/z 757→649 for [D9]-asunaprevir,and a collision energy of 30 electron Volts (eV). The assay was validated over a standard curve range from 0.05 to 50ng/mL for asunaprevir in human plasma. The intra- and inter assay precisions were within 7.1% CV, and the % deviation was within 5.5% of their nominal concentrations. This assay has been successfully applied to multiple clinical studies with excellent assay ruggedness and reproducibility.

A validated high-throughput UHPLC-MS/MS assay for accurate determination of rivaroxaban in plasma sample

Rivaroxaban is a novel, selective and potent oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. Like traditional anticoagulants, routine coagulation monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In this study, a sensitive UHPLC-MS/MS assay for rapid determination of rivaroxaban in human plasma was developed and validated. Rivaroxaban and its internal standard (IS) were extracted from plasma using acetonitrile as protein precipitating agent. An isocratic mobile phase of acetonitrile: 10 mM ammonium acetate (80:20, v/v) at a flow rate of 0.3 mL/min was used for the separation of rivaroxaban and IS. Both rivaroxaban and IS was eluted within 1 min with a total run time of 1.5 min only. Electrospray ionization source in positive mode was used for the detections of rivaroxaban and IS. Precursor to product ion transition of m/z 436.00 > 144.87 for rivaroxaban and m/z 411.18 > 191.07 for IS were used in multiple reaction monitoring mode. Developed assay was fully validated in terms of selectivity, linearity, accuracy, precision, recovery, matrix effects and stability using official guideline on bioanalytical method.

Quantitative hydrophilic interaction chromatography-mass spectrometry analysis of N-acetylneuraminic acid and N-acetylmannosamine in human plasma

N-acetylneuraminic acid (Neu5Ac or NANA) is the most predominant sialic acid in mammals. As a terminal component in many glycoproteins and glycolipids, sialic acid is believed to be an important biomarker related to various diseases. Its precursor, N-acetylmannosamine (ManNAc), is being investigated as a potential treatment for GNE myopathy. In this work, we developed two highly sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for the quantitation of ManNAc and free Neu5Ac in human plasma. A fit-for-purpose approach was adopted during method validation and sample analysis. To measure the endogenous compounds and overcome the interference from plasma samples, a surrogate matrix that contained 5% bovine serum albumin (BSA) was used for the preparation of calibration standards and certain levels of quality control (QC) samples. QC samples at higher concentrations were prepared in the authentic matrix (human plasma) to best mimic incurred samples. For both methods, an Ostro 96-well phospholipid removal plate was used for sample extraction, which efficiently removed the phospholipids from the plasma samples prior to LC injection, eliminated matrix effect, and improved sensitivity. Chromatographic separation was achieved using hydrophilic interaction chromatography (HILIC) and gradient elution in order to retain the two polar compounds. The lower limit of quantitation (LLOQ) for ManNAc and Neu5Ac was 10.0 and 25.0ng/mL, respectively. The overall accuracy of the two assays was within 100%±8.3% based on three levels of QC samples. Inter- and intra-run precision (coefficient of variation (%CV)) across three analytical runs was less than 6.7% for ManNAc and less than 10.8% for Neu5Ac. These methods have been validated to support clinical studies.

Current advances and strategies towards fully automated sample preparation for regulated LC–MS/MS bioanalysis

Robotic liquid handlers (RLHs) have been widely used in automated sample preparation for liquid chromatography–tandem mass spectrometry (LC–MS/MS) bioanalysis. Automated sample preparation for regulated bioanalysis offers significantly higher assay efficiency, better data quality and potential bioanalytical cost-savings. For RLHs that are used for regulated bioanalysis, there are additional requirements, including 21 CFR Part 11 compliance, software validation, system qualification, calibration verification and proper maintenance. This article reviews recent advances in automated sample preparation for regulated bioanalysis in the last 5 years. Specifically, it covers the following aspects: regulated bioanalysis requirements, recent advances in automation hardware and software development, sample extraction workflow simplification, strategies towards fully automated sample extraction, and best practices in automated sample preparation for regulated bioanalysis.

Rapid determination of canagliflozin in rat plasma by UHPLC-MS/MS using negative ionization mode to avoid adduct-ions formation

Canagliflozin is the first sodium-glucose co-transporter-2 inhibitor, approved by the US Food and Drug Administration for the treatment of type 2 diabetes mellitus. In this study, a sensitive UHPLC-MS/MS assay for rapid determination of canagliflozin in rat plasma was developed and validated for the first time. Chromatographic separation of canagliflozin and zafirlukast (IS) was carried out on Acquity BEH C18 column (100×2.1 mm, i.d. 1.7 µm) using acetonitrile-water (80:20, v/v) as mobile phase at a flow rate of 0.3 mL min(-1). Canagliflozin and IS were extracted from plasma by protein precipitation method using acetonitrile. The mass spectrometric detection was performed using electrospray ionization source in negative mode to avoid canagliflozin adduct ions formation. Multiple reaction monitoring were used for quantitation of precursor to product ion at m/z 443.16 >364.96 for canagliflozin and m/z 574.11>462.07 for IS, respectively. The assay was fully validated in terms of selectivity, linearity, accuracy, precision, recovery, matrix effects and stability. The validated method was successfully applied to the characterization of oral pharmacokinetic profiles of canagliflozin in rats. The mean maximum plasma concentration of canagliflozin of 1616.79 ng mL(-1) was achieved in 1.5 h after oral administration of 20 mg kg(-1) in rats.

Metabolomics in plants and humans: applications in the prevention and diagnosis of diseases

In the recent years, there has been an increase in the number of metabolomic approaches used, in parallel with proteomic and functional genomic studies. The wide variety of chemical types of metabolites available has also accelerated the use of different techniques in the investigation of the metabolome. At present, metabolomics is applied to investigate several human diseases, to improve their diagnosis and prevention, and to design better therapeutic strategies. In addition, metabolomic studies are also being carried out in areas such as toxicology and pharmacology, crop breeding, and plant biotechnology. In this review, we emphasize the use and application of metabolomics in human diseases and plant research to improve human health.

A systematic approach for developing a robust LC–MS/MS method for bioanalysis

In order to meet the drug discovery and development needs of pharmaceutical companies, CROs are constantly challenged by the requirements for rapid LC–MS/MS method development prior to method validation and sample analysis. In order to meet this challenge, a comprehensive method development program, nicknamed ‘Amoeba™’, which uses a series of written protocols for standardized and efficient method development was developed. In this paper, the genesis of the Amoeba method development program is elucidated in detail and a number of case studies are presented to showcase the execution of the Amoeba method development program. Using this program, the majority of the most critical information regarding the assay can be captured. While the Amoeba program has been proven to be effective, we recognize that the development of a robust bioanalytical method for use in pharmaceutical industry also requires the careful consideration of many critical parameters and the ability to identify and resolve potential issues. The refinement of the assay relies on further evaluation of several critical factors including, but not limited to, internal standard response, matrix effects (phospholipid or nonphospholipid related) and carryover.

Bioanalysis of drug in tissue: current status and challenges

Distribution of drugs into tissues is an important determinant of the overall PK and PD profile. Thus, bioanalysis of drugs and their metabolites in tissues can play an important role in understanding the pharmacological and toxicological properties of new drug candidates. Unlike liquid matrices, bioanalysis in tissues offers unique challenges such as proper tissue sampling, appropriate tissue sample preparation, efficient extraction of the analytes from the tissue homogenates, and demonstration of stability and recovery of analytes in intact tissues. This article provides a systematic review of tissue sample analysis for small molecules using LC–MS/MS. The authors provide rationale for tissue sample analysis, and discuss strategies for method development, method qualification or validation, and sample analysis. Unique aspects of method development and qualification/validation are highlighted based on authors’ direct experiences and literature summary. Analysis using intact tissue samples such as MALDI imaging is also briefly discussed.

Investigation of microbore UPLC and nontraditional mobile phase compositions for bioanalytical LC-MS/MS

BACKGROUND

The movement towards environmentally friendly or green chemistry solutions has gained more prominence recently in the scientific community. One way in which scientists can address this issue is to limit the use of hazardous chemicals in their everyday processes. Therefore, the focus of this study was on the utilization of microbore-scale chromatography and nontraditional alcoholic mobile phases as an alternative approach to traditional bioanalytical LC-MS/MS assay parameters.

RESULTS

Replacement of the traditional narrowbore LC column with a microbore format reduced solvent consumption and produced a greater than threefold increase in S/N. The nontraditional alcoholic mobile phases, ethanol or isopropanol, produced either greater peak area counts, or S/N, for over half of the compounds evaluated, compared with the traditional organic mobile phases of acetonitrile and methanol. These nontraditional alcoholic mobile phases also showed improved capability in the removal of plasma phospholipid components from the chromatographic column. The ionizable background detected in each of the organic mobile phases utilized in this study produced a unique background that may or may not interfere with compounds undergoing analysis.

CONCLUSION

The combination of microbore columns and nontraditional alcoholic mobile phases has been shown to produce effective, alternative method conditions to traditional bioanalytical LC-MS/MS method parameters.

Separation technique for the determination of highly polar metabolites in biological samples

Metabolomics is a new approach that is based on the systematic study of the full complement of metabolites in a biological sample. Metabolomics has the potential to fundamentally change clinical chemistry and, by extension, the fields of nutrition, toxicology, and medicine. However, it can be difficult to separate highly polar compounds. Mass spectrometry (MS), in combination with capillary electrophoresis (CE), gas chromatography (GC), or high performance liquid chromatography (HPLC) is the key analytical technique on which emerging "omics" technologies, namely, proteomics, metabolomics, and lipidomics, are based. In this review, we introduce various methods for the separation of highly polar metabolites.

Direct injection of lipophilic compounds in the organic phase from liquid–liquid extracted plasma samples onto a reversed-phase column

Background: A high-throughput bioanalytical methodology for analysis and quantification of lipophilic pharmaceutical compounds in plasma using liquid–liquid extraction (LLE) was developed. Results: A fast and robust alternative to the widely used protein precipitation of plasma samples is sometimes required in order to avoid matrix effects in MS detection. LLE is known to produce clean extracts and hence reduce levels of matrix components that cause ion suppression. The proposed sample preparation was automated LLE using 96-well plates and a Tecan GenMate 96-tips liquid handling robot. With direct injection of the organic phase (methyl tert-butyl ether: iso-hexane 50:50 v/v) onto a reversed-phase column and without evaporation of the organic phase and reconstitution of the sample, the LLE was no more time consuming than standard protein precipitation, furthermore, matrix effects were minimized. The small injection volume (5 µl) when used with lipophilic compounds and a rapid gradient elution made it possible to inject the organic phase with maintained chromatographic performance. Good chromatographic behavior was confirmed for eight commercially available lipophilic compounds. Conclusions: The proposed method of LLE with injection of the organic phase onto a reversed-phase column in LC–MS/MS is no more time consuming than standard protein precipitation, and matrix effects were minimized, thus making it suitable as a high-throughput bioanalytical methodology for use in drug discovery.

Minimizing matrix effects while preserving throughput in LC–MS/MS bioanalysis

Background: Phospholipids are known to cause matrix effects in LC–MS analysis and are not effectively removed by one of the most common method of sample preparation: organic solvent protein precipitation. The objective of this research is to minimize phospholipid interferences chromatographically. Results: In this article we examine several chromatographic approaches and highlight the method we developed that allows for the rapid gradient separation of model drug molecules from phospholipids. Conclusion: The new approach (which utilizes a mixture of methanol and acetonitrile as the organic mobile phase on a 2.1 × 20 mm C18 column) minimized phospholipids-related matrix effects in the analysis of plasma samples prepared by protein precipitation and is suitable for high-throughput bioanalysis in drug discovery.

Implementation of high-temperature superficially porous technologies for rapid LC–MS/MS diastereomer bioanalysis

Background: The fast-paced nature of the pharmaceutical industry requires robust bioanalytical methods to endure the high-throughput sample demands of the production environment. Results: A rapid, accurate and precise LC–MS/MS method was developed for the quantitation of a diastereomer quartet in human plasma. Virtually all of the phosphatidylcholine and most of the lysophosphatidylcholine from human plasma were removed using a phospholipid-removing protein precipitation 96-well plate. An Agilent Poroshell SB-C18 2.1 × 50 mm superficially porous column was used at 100°C and 1.2 ml/min to separate a diastereomer quartet in <2.5 min. Peak shape, retention and resolution were maintained over nearly 200 extracted bioanalytical samples under these separation conditions. The method was tested for accuracy and precision; the assay inter-run accuracy and precision were minus 7.2–0.7% and 2.1–11.9%, respectively (n = 18). Conclusion: The application of the superficially porous column resulted in twofold response increase and a 2.6-fold reduction in cycle time compared with a 3.5-µm column performing under comparable resolution conditions.

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.

Evaluating and defining sample preparation procedures for DBS LC–MS/MS assays

Background: A defined approach to develop and validate an LC–MS/MS assay using dried blood spot (DBS) samples is of great interest to many scientists who are adopting this technology. We have evaluated three distinct sample preparation procedures of DBS samples for LC–MS/MS assay development. Results: A new term ‘elution efficiency’ is introduced to evaluate the effectiveness of eluting compounds from the DBS cards into the liquid phase. Three different types of DBS cards were studied as part of the sample preparation procedures. A DBS LC–MS/MS method was developed, qualified and then applied to a toxicokinetics study. Conclusion: Organic extraction and protein precipitation resulted in significant ion suppression and/or enhancement for FTA® Classic or FTA® Elute cards. Liquid–liquid extraction produced the least ion suppression/enhancement. Both protein precipitation and liquid–liquid extraction effectively eluted the probe compound from the DBS cards under the conditions tested. However, organic extraction by pure solvents resulted in low elution efficiency.

Size effect on fragmentation in tandem mass spectrometry

The collision energy or collision voltage necessary to obtain 50% fragmentation (characteristic collision energy/voltage, CCE or CCV) has been systematically determined for different types of molecules [poly(ethylene glycols) (PEG), poly(tetrahydrofuran) (PTHF), and peptides] over a wide mass (degrees of freedom) range. In the case of lithium-cationized PEGs a clear linear correlation (R(2) > 0.996) has been found between CCE and precursor ion mass on various instrument types up to 4.5 kDa. A similar linear correlation was observed between CCV and the mass-to-charge ratio. For singly and multiply charged polymers studied under a variety of experimental conditions and on several instruments, all data were plotted together and showed correlation coefficient R(2) = 0.991. A prerequisite to observe such a good linear correlation is that the energy and entropy of activation in a class of polymers is likely to remain constant. When compounds of different structure are compared, the CCV will depend not only on the molecular mass but the activation energy and entropy as well. This finding has both theoretical and practical importance. From a theoretical point of view it suggests fast energy randomization up to at least 4.5 kDa so that statistical rate theories are applicable in this range. These results also suggest an easy method for instrument tuning for high-throughput structural characterization through tandem MS: after a standard compound is measured, the optimum excitation voltage is in a simple proportion with the mass of any structurally similar analyte at constant experimental conditions.