RESUMO
In the last few years, an increasing number of dried blood spot (DBS) sampling assays have been developed. With this increase, more insight is gained in the factors that possibly influence the performance of DBS assays. We have developed an assay for four commonly used immunosuppressants; some of them are possibly concomitantly prescribed: cyclosporin A (CsA), tacrolimus (TcR), sirolimus (SiR), and everolimus (EvE). Chromatographic separation from possible ion suppression was obtained within the total runtime of 4.2 min. Trifluoroacetic acid and ammonium acetate were used as mobile phase additives. The linearity ranged from 23.6 to 787, 1.14 to 30.3, 1.34 to 35.8, and 1.26 to 33.7 µg/L, for CsA, TcR, SiR, and EvE, respectively. Between- and within-run accuracy and precision were all within 15 % and extensive validation for DBS samples, such as hematocrit, blood spot volume, and spot punch location was performed. None of these factors were found to be of influence on the performance of the DBS assay.
Assuntos
Cromatografia Líquida/métodos , Ciclosporina/sangue , Teste em Amostras de Sangue Seco/métodos , Imunossupressores/sangue , Sirolimo/análogos & derivados , Sirolimo/sangue , Tacrolimo/sangue , Espectrometria de Massas em Tandem/métodos , Everolimo , HumanosRESUMO
At our laboratory a reversed phase high performance liquid chromatography assay was developed for analysis of mycophenolic acid in dried blood spot samples. The assay was validated in the range of 0.74-23.4mg/L and proved to be accurate and precise. The developed sample pretreatment procedure was consistent and has a recovery of 95.2% for mycophenolic acid. Hematocrit showed to have influence on the physics of the blood spots and thus on the concentration of mycophenolic acid, therefore standard and control samples should be made with a standardized hematocrit.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Ácido Micofenólico/sangue , Estabilidade de MedicamentosRESUMO
A quantitative liquid chromatography (LC)-mass spectrometry (MS)/MS method in human plasma was developed and validated for the tyrosine kinase inhibitors erlotinib, gefitinib, and imatinib in human plasma. Pre-treatment of the samples was achieved by using liquid-liquid extraction using D-8 imatinib as internal standard. Separation was performed on a Waters Alliance 2795 LC system using an XBridge RP18 column. The mass spectrometer Micromass was equipped with an electro spray ionization probe, operating in the positive mode. The calibration curves in plasma were linear for erlotinib, gefitinib, and imatinib over the concentration range of 5 to 3,000; 5 to 3,000, and 5 to 5,000 ng/mL, respectively. The intraday and interday accuracy ranged from 90% to 110% and the intraday and interday precision of the method was within 5%. The reported method provided the necessary linearity, precision, and accuracy to determine tyrosine kinase inhibitors in clinical research and for therapeutic drug monitoring.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Piperazinas/sangue , Pirimidinas/sangue , Quinazolinas/sangue , Espectrometria de Massas em Tandem/métodos , Métodos Analíticos de Preparação de Amostras , Benzamidas , Calibragem , Monitoramento de Medicamentos/métodos , Cloridrato de Erlotinib , Gefitinibe , Humanos , Mesilato de Imatinib , Microquímica , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray/métodosRESUMO
Dried blood spot sampling is a promising and patient friendly alternative for venous sampling. A liquid chromatography tandem mass spectrometer assay was developed for analyzing cyclosporin A in dried blood spots. Linearity ranged from 25 to 1440 microg/L. Within and between run accuracy and precision were within limits. The developed assay has a negligible matrix-effect and a recovery of 97%. The dried blood spots were stable during a period of at least 17 days in the refrigerator. The developed assay is suitable for analyzing cyclosporin A in dried blood spots.