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1.
Clin Pharmacol Ther ; 115(5): 939-953, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38073140

RESUMO

The intent of this perspective is to share the recommendations of the International Consortium for Innovation and Quality in Pharmaceutical Development Metabolite Bioanalysis Working Group on the fit-for-purpose metabolite bioanalysis in support of drug development and registration. This report summarizes the considerations for the trigger, timing, and rigor of bioanalysis in the various assessments to address unique challenges due to metabolites, with respect to efficacy and safety, which may arise during drug development from investigational new drug (IND) enabling studies, and phase I, phase II, and phase III clinical trials to regulatory submission. The recommended approaches ensure that important drug metabolites are identified in a timely manner and properly characterized for efficient drug development.


Assuntos
Desenvolvimento de Medicamentos , Relatório de Pesquisa , Humanos
2.
Bioanalysis ; 14(9): 505-580, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35578993

RESUMO

The 15th edition of the Workshop on Recent Issues in Bioanalysis (15th WRIB) was held on 27 September to 1 October 2021. Even with a last-minute move from in-person to virtual, an overwhelmingly high number of nearly 900 professionals representing pharma and biotech companies, contract research organizations (CROs), and multiple regulatory agencies still eagerly convened to actively discuss the most current topics of interest in bioanalysis. The 15th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines. Moreover, in-depth workshops on biomarker assay development and validation (BAV) (focused on clarifying the confusion created by the increased use of the term "Context of Use - COU"); mass spectrometry of proteins (therapeutic, biomarker and transgene); state-of-the-art cytometry innovation and validation; and, critical reagent and positive control generation were the special features of the 15th edition. This 2021 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2021 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1A) covers the recommendations on Endogenous Compounds, Small Molecules, Complex Methods, Regulated Mass Spec of Large Molecules, Small Molecule, PoC. Part 1B covers the Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine. Part 2 (ISR for Biomarkers, Liquid Biopsies, Spectral Cytometry, Inhalation/Oral & Multispecific Biotherapeutics, Accuracy/LLOQ for Flow Cytometry) and Part 3 (TAb/NAb, Viral Vector CDx, Shedding Assays; CRISPR/Cas9 & CAR-T Immunogenicity; PCR & Vaccine Assay Performance; ADA Assay Comparabil ity & Cut Point Appropriateness) are published in volume 14 of Bioanalysis, issues 10 and 11 (2022), respectively.


Assuntos
Vesículas Extracelulares , Vacinas , Biomarcadores/análise , Terapia Baseada em Transplante de Células e Tecidos , Vesículas Extracelulares/química , Humanos , Espectrometria de Massas/métodos , Nanomedicina
3.
Bioanalysis ; 13(4): 203-238, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33470871

RESUMO

The 14th edition of the Workshop on Recent Issues in Bioanalysis (14th WRIB) was held virtually on June 15-29, 2020 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. The 14th WRIB included three Main Workshops, seven Specialized Workshops that together spanned 11 days in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccine. Moreover, a comprehensive vaccine assays track; an enhanced cytometry track and updated Industry/Regulators consensus on BMV of biotherapeutics by Mass Spectrometry (hybrid assays, LCMS and HRMS) were special features in 2020. As in previous years, this year's WRIB continued to gather a wide diversity of international industry opinion leaders and regulatory authority experts working on both small and large molecules to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance and achieving scientific excellence on bioanalytical issues. This 2020 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the Global Bioanalytical Community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2020 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication covers the recommendations on (Part 1) Hybrid Assays, Innovation in Small Molecules, & Regulated Bioanalysis. Part 2A (BAV, PK LBA, Flow Cytometry Validation and Cytometry Innovation), Part 2B (Regulatory Input) and Part 3 (Vaccine, Gene/Cell Therapy, NAb Harmonization and Immunogenicity) are published in volume 13 of Bioanalysis, issues 5, and 6 (2021), respectively.


Assuntos
Bioensaio/métodos , Terapia Baseada em Transplante de Células e Tecidos/métodos , Terapia Genética/métodos , Espectrometria de Massas/métodos , História do Século XXI , Humanos
5.
Bioanalysis ; 11(23): 2099-2132, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31833782

RESUMO

The 2019 13th Workshop on Recent Issues in Bioanalysis (WRIB) took place in New Orleans, LA on 1-5 April 2019 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day, week-long event - a full immersion week of bioanalysis, biomarkers, immunogenicity and gene therapy. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small- and large-molecule bioanalysis involving LCMS, hybrid LBA/LCMS, LBA cell-based/flow cytometry assays and qPCR approaches. This 2019 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2019 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 2) covers the recommendations on the 2018 FDA BMV guidance, 2019 ICH M10 BMV draft guideline and regulatory agencies' input on bioanalysis, biomarkers, immunogenicity and gene therapy. Part 1 (Innovation in small molecules and oligonucleotides and mass spectrometry method development strategies for large molecules bioanalysis) and Part 3 (New insights in biomarker assay validation, current and effective strategies for critical reagent management, flow cytometry validation in drug discovery and development and CLSI H62, interpretation of the 2019 FDA immunogenicity guidance and gene therapy bioanalytical challenges) are published in volume 10 of Bioanalysis, issues 22 and 24 (2019), respectively.


Assuntos
Bioensaio/normas , Biomarcadores/análise , Guias como Assunto , Fenômenos Imunogenéticos , Relatório de Pesquisa , United States Food and Drug Administration/legislação & jurisprudência , Humanos , Estados Unidos
6.
Bioanalysis ; 11(18): 1657-1667, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31556309

RESUMO

Aim: Monitoring the internal standard (IS) response is common practice in bioanalysis by LC-MS/MS. IS response variation may raise questions on assay quality and should trigger investigations into the root cause. Results: In two case studies with IS variability, re-analysis of diluted samples and spiking predose study samples revealed no effect of IS variability on results. The D17-labeled IS in a third case proved not to be suitable during method development and was replaced by a differently labeled IS. Conclusion: Determining the exact root cause for varying IS response is not always feasible; however, assay accuracy and reliability of results should be demonstrated. In some cases, assay re-development is needed to solve the problem.


Assuntos
Cromatografia Líquida/normas , Espectrometria de Massas em Tandem/normas , Calibragem , Humanos , Metabolismo , Padrões de Referência
7.
Bioanalysis ; 10(22): 1781-1801, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30488725

RESUMO

The 2018 12th Workshop on Recent Issues in Bioanalysis (12th WRIB) took place in Philadelphia, PA, USA on April 9-13, 2018 with an attendance of over 900 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day full immersion in bioanalysis, biomarkers and immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small- and large-molecule bioanalysis involving LC-MS, hybrid ligand binding assay (LBA)/LC-MS and LBA/cell-based assays approaches. This 2018 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2018 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1) covers the recommendations for LC-MS for small molecules, peptides, oligonucleotides and small molecule biomarkers. Part 2 (hybrid LBA/LC-MS for biotherapeutics and regulatory agencies' inputs) and Part 3 (large molecule bioanalysis, biomarkers and immunogenicity using LBA and cell-based assays) are published in volume 10 of Bioanalysis, issues 23 and 24 (2018), respectively.


Assuntos
Biomarcadores/análise , Oligonucleotídeos/análise , Peptídeos/análise , Animais , Cromatografia Líquida , Humanos , Espectrometria de Massas , Philadelphia
8.
Bioanalysis ; 9(24): 1997-2014, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29205056

RESUMO

There are many ocular diseases still presenting unmet medical needs. Therefore, new ophthalmologic drugs are being developed. Bioanalysis of eye compartments (along with plasma and other tissues) is important to determine exposure of the target organ to the drug and to help interpret local pharmacological or toxic effects. This review article identifies several challenges that occur within ocular bioanalysis. They include sample collection and preparation, analytical issues, sourcing control matrix, data interpretation and regulatory requirements. It summarizes how these challenges have been recently addressed, how research has advanced and which questions remain unanswered. Recommendations are made based on the literature and our practical experience within ocular bioanalysis and future perspectives are discussed.


Assuntos
Olho/química , Preparações Farmacêuticas/análise , Animais , Cromatografia Líquida de Alta Pressão , Córnea/química , Córnea/metabolismo , Olho/metabolismo , Humanos , Preparações Farmacêuticas/metabolismo , Farmacocinética , Manejo de Espécimes , Espectrometria de Massas em Tandem , Lágrimas/química , Lágrimas/metabolismo
9.
Bioanalysis ; 9(22): 1807-1825, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29148835

RESUMO

The 2017 11th Workshop on Recent Issues in Bioanalysis (11th WRIB) took place in Los Angeles/Universal City, California from 3 April 2017 to 7 April 2017 with participation of close to 750 professionals from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day, weeklong event - A Full Immersion Week of Bioanalysis, Biomarkers and Immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small and large molecule analysis involving LCMS, hybrid LBA/LCMS and ligand-binding assay (LBA) approaches. This 2017 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2017 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1) covers the recommendations for Small Molecules, Peptides and Small Molecule Biomarkers using LCMS. Part 2 (Biotherapeutics, Biomarkers and Immunogenicity Assays using Hybrid LBA/LCMS and Regulatory Agencies' Inputs) and Part 3 (LBA: Immunogenicity, Biomarkers and PK Assays) are published in volume 9 of Bioanalysis, issues 23 and 24 (2017), respectively.


Assuntos
Biomarcadores/análise , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Peptídeos/análise , Bibliotecas de Moléculas Pequenas/análise , Conferências de Consenso como Assunto , Guias como Assunto , Ligantes , Bibliotecas de Moléculas Pequenas/química
10.
Bioanalysis ; 9(5): 459-468, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28176528

RESUMO

AIM: Alectinib (Alecensa®) is an anaplastic lymphoma kinase inhibitor for the treatment of anaplastic lymphoma kinase positive non-small-cell lung cancer, and M4 is its major pharmacologically active metabolite. To characterize the pharmacokinetics and excretion of alectinib and M4 in human urine, a bioanalytical method was required. RESULTS: An LC-MS/MS method using supported liquid extraction was developed for the determination of alectinib and M4 in human urine over the concentration range 0.5-500 ng/ml. Accuracy ranged from 92.0 to 112.2% and precision (CV) was below 9.6%. CONCLUSION: The method was successfully employed to determine alectinib and M4 concentrations in urine samples from a clinical mass balance study. Addition of the surfactant Tween-20 to urine prevented nonspecific binding of the analytes.


Assuntos
Carbazóis/urina , Cromatografia Líquida de Alta Pressão/métodos , Piperidinas/urina , Inibidores de Proteínas Quinases/urina , Espectrometria de Massas em Tandem/métodos , Carbazóis/metabolismo , Carbazóis/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Cromatografia Líquida de Alta Pressão/normas , Humanos , Piperidinas/metabolismo , Piperidinas/uso terapêutico , Inibidores de Proteínas Quinases/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Controle de Qualidade , Espectrometria de Massas em Tandem/normas
11.
Bioanalysis ; 9(3): 297-312, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28111961

RESUMO

AIM: Midazolam is a commonly used marker substrate for the in vivo assessment of CYP3A activity. Reliable pharmacokinetic assessment at sub-pharmacological doses of midazolam requires an ultra-sensitive analytical method. METHODS: A new, ultra-sensitive LC-MS/MS method for the determination of midazolam in human plasma using SPE was developed and fully validated. The lowest limit of quantitation is 0.1 pg/ml with a sample volume of 500 µl. RESULTS/CONCLUSION: The following parameters were validated: sensitivity, assay accuracy and precision, linearity, selectivity, and stability of midazolam at pertinent analytical and storage conditions. The validated method was utilized successfully for the sample assay during a midazolam microdosing study for the evaluation of CYP3A4 activity of a clinical candidate.


Assuntos
Cromatografia Líquida/métodos , Midazolam/sangue , Espectrometria de Massas em Tandem/métodos , Estabilidade de Medicamentos , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
12.
Bioanalysis ; 8(22): 2363-2378, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27712081

RESUMO

The 2016 10th Workshop on Recent Issues in Bioanalysis (10th WRIB) took place in Orlando, Florida with participation of close to 700 professionals from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. WRIB was once again a 5-day, weeklong event - A Full Immersion Week of Bioanalysis including Biomarkers and Immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small and large molecule analysis involving LCMS, hybrid LBA/LCMS, and LBA approaches, with the focus on biomarkers and immunogenicity. This 2016 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. This white paper is published in 3 parts due to length. This part (Part 1) discusses the recommendations for small molecules, peptides and small molecule biomarkers by LCMS. Part 2 (Hybrid LBA/LCMS and regulatory inputs from major global health authorities) and Part 3 (large molecule bioanalysis using LBA, biomarkers and immunogenicity) will be published in the Bioanalysis journal, issue 23.

13.
Bioanalysis ; 8(14): 1465-79, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27329641

RESUMO

BACKGROUND: Alectinib is a novel anaplastic lymphoma kinase (ALK) inhibitor for treatment of patients with ALK-positive non-small-cell lung cancer who have progressed on or are intolerant to crizotinib. To support clinical development, concentrations of alectinib and metabolite M4 were determined in plasma from patients and healthy subjects. METHODS: LC-MS/MS methods were developed and validated in two different laboratories: Chugai used separate assays for alectinib and M4 in a pivotal Phase I/II study while Roche established a simultaneous assay for both analytes for another pivotal study and all other studies. CONCLUSION: Cross-validation assessment revealed a bias between the two bioanalytical laboratories, which was confirmed with the clinical PK data between both pivotal studies using the different bioanalytical methods.


Assuntos
Carbazóis/sangue , Carbazóis/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Piperidinas/sangue , Piperidinas/metabolismo , Inibidores de Proteínas Quinases/sangue , Inibidores de Proteínas Quinases/metabolismo , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Espectrometria de Massas em Tandem/métodos , Quinase do Linfoma Anaplásico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/enzimologia , Cromatografia Líquida de Alta Pressão/instrumentação , Desenho de Equipamento , Humanos , Limite de Detecção , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/enzimologia , Espectrometria de Massas em Tandem/instrumentação
14.
Clin Pharmacokinet ; 55(7): 875-887, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26895021

RESUMO

BACKGROUND: The emergence of genetic data linking Nav1.7 sodium channel over- and under- expression to human pain signalling has led to an interest in the treatment of chronic pain through inhibition of Nav1.7 channels. OBJECTIVE: We describe the pharmacokinetic (PK) results of a clinical microdose study performed with four potent and selective Nav1.7 inhibitors and the subsequent modelling resulting in the selection of a single compound to explore Nav1.7 pharmacology at higher doses. METHODS: A clinical microdose study to investigate the intravenous and oral PK of four compounds (PF-05089771, PF-05150122, PF-05186462 and PF-05241328) was performed in healthy volunteers. PK parameters were derived via noncompartmental analysis. A physiologically-based PK (PBPK) model was used to predict exposure and multiples of Nav1.7 50 % inhibitory concentration (IC50) for each compound at higher doses. RESULTS: Plasma clearance, volume of distribution and bioavailability ranged from 45 to 392 mL/min/kg, 13 to 36 L/kg and 38 to 110 %, respectively. The PBPK model for PF-05089771 predicted a 1 g oral dose would be required to achieve exposures of approximately 12× Nav1.7 IC50 at maximum concentration (C max), and approximately 3× IC50 after 12 h (minimum concentration [C min] for a twice-daily regimen). Lower multiples of Nav1.7 IC50 were predicted with the same oral doses of PF-05150122, PF-05186462, and PF-05241328. In a subsequent single ascending oral dose clinical study, the predictions for PF-05089771 compared well with observed data. CONCLUSION: Based on the human PK data obtained from the microdose study and subsequent modelling, PF-05089771 provided the best opportunity to explore Nav1.7 blockade for the treatment of acute or chronic pain conditions.


Assuntos
Éteres Fenílicos/administração & dosagem , Éteres Fenílicos/farmacocinética , Sulfonamidas/administração & dosagem , Sulfonamidas/farmacocinética , Bloqueadores do Canal de Sódio Disparado por Voltagem/administração & dosagem , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacocinética , Adolescente , Adulto , Área Sob a Curva , Disponibilidade Biológica , Relação Dose-Resposta a Droga , Método Duplo-Cego , Humanos , Concentração de Íons de Hidrogênio , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Modelos Biológicos , Adulto Jovem
15.
J Neurosci Methods ; 185(1): 39-44, 2009 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-19747947

RESUMO

Direct measurement of absolute brain concentration of amphetamine and dopamine were obtained using metaquant (MQ) microdialysis, which achieves near 100% recovery, in the caudate nucleus. Conventional microdialysis monoprobes were also implanted in the caudate nucleus in the contralateral side of the same animals to compare the brain concentrations obtained from these two probe types. In addition plasma concentrations of amphetamine were obtained simultaneously from the same animals. The distribution of amphetamine in the plasma and of amphetamine and dopamine in both probe types followed same profile at each time interval. The basal dialysate concentration of dopamine in the caudate nucleus measured by MQ, was 9.40+/-0.60 nM, while measured by conventional microdialysis it was 6.35+/-0.36 nM. This study demonstrates that MQ microdialysis is an appropriate method for determination of true extracellular levels of drugs and neurotransmitters in the brain, under dynamic conditions. Since these measurements, together with measurements of plasma concentrations of the drug, can be made in a single animal, the method can be used to study pharmacokinetic-pharmacodyamics profile of psychoactive agents.


Assuntos
Anfetamina/análise , Química Encefálica/fisiologia , Dopamina/análise , Microdiálise/métodos , Neuroquímica/métodos , Neurofarmacologia/métodos , Anfetamina/sangue , Anfetamina/farmacocinética , Animais , Análise Química do Sangue/métodos , Núcleo Caudado/química , Núcleo Caudado/efeitos dos fármacos , Núcleo Caudado/metabolismo , Dopamina/sangue , Dopamina/farmacocinética , Líquido Extracelular/química , Líquido Extracelular/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
16.
J Pharm Biomed Anal ; 49(1): 133-9, 2009 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-19058944

RESUMO

A sensitive liquid chromatography-mass spectrometry (LC-MS) method has been developed for stereoselective determination of reboxetine in rat plasma and brain homogenate (LLOQ, 50 pg/ml). The method optimised ionisation efficiency with an electro-ionspray source, by adjusting the composite flow conditions (rate, pH, organic content) from column eluent and post-column organic modifier. LC conditions utilized a chiral AGP column (5 microm) with 12.5 mM ammonium carbonate buffer adjusted with formic acid (pH 6.7) and included a wash step (0.05% acetic acid in water) to maintain assay robustness and chromatographic performance. The total method cycle time was 23 min. Imprecision (R.S.D.) was below 10% and inaccuracy (% error) below 7% for both enantiomers in plasma and brain homogenate, over a 2000-fold dynamic range (0.05-100 ng/ml). An automated liquid-liquid extraction technique was used (borate buffer, pH 10/tert-butyl methyl ether) and the matrix type used produced no difference in the assay performance. The method was successfully applied to determine the pharmacokinetic profiles of S,S- and R,R-reboxetine in rats, following subcutaneous administration of racemate drug.


Assuntos
Inibidores da Captação Adrenérgica/sangue , Química Encefálica , Cromatografia Líquida/métodos , Morfolinas/sangue , Espectrometria de Massas em Tandem/métodos , Inibidores da Captação Adrenérgica/química , Inibidores da Captação Adrenérgica/farmacocinética , Animais , Estabilidade de Medicamentos , Congelamento , Concentração de Íons de Hidrogênio , Estrutura Molecular , Morfolinas/química , Morfolinas/farmacocinética , Controle de Qualidade , Ratos , Reboxetina , Padrões de Referência , Sensibilidade e Especificidade , Espectrometria de Massas por Ionização por Electrospray , Estereoisomerismo
17.
J Chromatogr B Analyt Technol Biomed Life Sci ; 856(1-2): 131-40, 2007 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-17574938

RESUMO

An online turbulent flow chromatography method coupled to tandem mass spectrometry (TFC-MS/MS) has been developed within our bioanalytical group, suited to the analysis of mid to late stage discovery compounds. A dual column configuration utilising isocratic focusing of the analyte upon the analytical column maintained an excellent peak shape for a large proportion of compounds encountered and enabled consistent quantitation to sub-nanogram concentrations (<15 pg on column). Furthermore, the low sample injection volume coupled with rapid column washing using basic and acidic mobile phases, has proved advantageous in removing sample carryover and also the overall exposure to biological material; favourable for good system robustness. All the data discussed were generated with a method cycle time of 5 min providing accurate quantitation (acceptance criteria based upon FDA method validation guidelines) with multiple analytes and biological matrices.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Preparações Farmacêuticas/análise , Padrões de Referência , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
18.
J Chromatogr B Analyt Technol Biomed Life Sci ; 853(1-2): 346-53, 2007 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-17481970

RESUMO

The evaluation of molecularly imprinted polymers (MIPs) as selective sorbents for the solid-phase extraction of sildenafil and its principal metabolite, desmethylsildenafil, was investigated. Two MIPs were synthesised using structural analogues of sildenafil as templates, and a comparison of the performance of the two MIP sorbents in organic and aqueous media was performed. Additionally, the feasibility of applying molecularly imprinted solid-phase extraction (MISPE) to the clean-up of plasma samples containing sildenafil and desmethylsildenafil was investigated. A preliminary, quantitative MISPE for the determination of both compounds in plasma was also performed. The results showed that the MIPs used for the selective extraction of sildenafil gave better compound recovery when aqueous samples were used in comparison to organic-based samples. A preliminary, quantitative MISPE of sildenafil and desmethylsildenafil indicated that the imprinted materials could be used successfully as SPE sorbents for sample pre-treatment for the determination of sildenafil, and related compounds, in plasma.


Assuntos
Piperazinas/sangue , Polímeros/química , Extração em Fase Sólida/métodos , Sulfonas/sangue , Água/química , Humanos , Estrutura Molecular , Piperazinas/química , Piperazinas/metabolismo , Purinas/sangue , Purinas/química , Purinas/metabolismo , Reprodutibilidade dos Testes , Citrato de Sildenafila , Sulfonas/química , Sulfonas/metabolismo
19.
J Pharm Biomed Anal ; 39(1-2): 206-16, 2005 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-15871916

RESUMO

Liquid chromatography-tandem mass spectrometry (LC/MS/MS) has become the technology of choice for bioanalysis, due to its high selectivity and high sample throughput. However, concerns have grown that this technique may be subject to errors due to "invisible" interferences, in particular ion-suppression. Investigations on ion-suppression from formulation agents have only been published to a limited extent. Such effects can be of particular importance in pre-clinical discovery studies where drugs may be formulated with large amount of solubilisers and bioanalysis may use fast generic methods. In a preliminary pharmacokinetic study we observed strong ion-suppression from a polysorbate co-solvent, which, if undetected, would have given highly erroneous pharmacokinetic results and possibly could have led to the inappropriate elimination of a promising drug candidate. Different chromatographic methods were tested indicating that the separation step was essential in controlling these effects. A method based on matrix dilution is proposed to check for these effects during the use of discovery support methods, where full validation is not practical. Some excipients commonly used in formulations are polydispersed polymers, for which very limited pharmacokinetic information is available. Further investigation is needed to better understand the mechanisms of ion-suppression and the kinetics of the suppressing species to allow the development of new LC/MS/MS based analytical strategies, which will not be subject to such ionisation interferences.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Preparações Farmacêuticas/análise , Animais , Química Farmacêutica , Ratos , Ratos Sprague-Dawley , Padrões de Referência , Sensibilidade e Especificidade
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