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Selective extractive phases for microextraction techniques for determination of drugs and an endocannabinoid in plasma samples by LC-MS/MS

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Mônia Aparecida Lemos Pinto de Melo
Total Authors: 1
Document type: Doctoral Thesis
Press: Ribeirão Preto.
Institution: Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC)
Defense date:
Examining board members:
Maria Eugenia Queiroz Nassur; José Alexandre de Souza Crippa; Jaime Eduardo Cecilio Hallak; Fernando Mauro Lanças
Advisor: Maria Eugenia Queiroz Nassur

This work describes the development of highly selective sorbents for use in microextraction techniques for determination of drugs and endocannabinoid in plasma samples by liquid chromatography coupled to Tandem mass spectrometry (LC-MS/MS). Chapter I describes the development and application of a restricted access material (RAM-BSA) for use as extractive phase in DPX technique (\"Disposable pipette extraction\") for determination of 16 psychotropic drugs in plasma samples obtained from schizophrenic patients. Polytherapy has been increasingly common in clinical practice associated with schizophrenia due the complexity of its symptoms. Most of these drugs have narrow therapeutic index, wherefore requires adequate follow-up through therapeutic monitoring studies. This monitoring aims to optimizing therapy, to minimize adverse effects and verify patient adherence to treatment. By using a selective phase, RAM, we were able to exclude the macromolecules and to pre-concentrate the analytes quickly and efficiently. Optimization of the DPX variables improved the sensitivity and selectivity of the method, which demanded only small volumes of sample and organic solvent. The DPX/LC-MS/MS method developed and validated presented adequate linearity; the lower limit of quantification ranged from 0.5 to 20.0 ng mL-1. The inter- and intra-assay precision tests provided coefficients of variation (CV) lower than 15%; and the relative standard error (RSD) values, of the accuracy tests, varied from -12% to 11%. We successfully applied the proposed method to determine drugs in plasma samples from schizophrenic patients. Variations in the plasma concentrations of drugs in some patients may result from pharmacokinetic interactions or variations inherent in the patient. Chapter II details the \"in situ\" synthesis of a molecularly imprinted polymer within a fused silica capillary for capillary solid phase (in-tube SPME) of the endocannabinoid, anandamide (AEA), in plasma samples obtained from patients with Parkinson\'s Disease (PD), which is characterized by neurodegeneration of dopaminergic neurons. Studies have demonstrated a relationship between this endocannabinoid and dopaminergic systems, which are linked to motor control. The molecular imprinting process (non-covalent) and the synthesis reagents used to obtain the MIP gave rise to complementary, selective sites with the same shape and size as AEA. Scanning electron micrographs (SEM) and infrared spectra (FTIR) helped to illustrate the physical and chemical modification of the printed and non-printed capillary surface (NIP) after polymerization. Optimization of in-tube SPME variables favored the extraction process efficiency. The \"in tube\" SPME/LC-MS/MS method showed a linear range from 5 ng mL-1 (LOQ) to 20 ng mL-1. The precision tests presented CV that varied from 1.2 to 13%; and the RSD accuracy ranged from -3.6 to 7.5%. We analyzed plasma samples from patients with PD by the standard addition method. The mean plasmatic concentration was 0.2 ng mL-1, in agreement with the literature. This resut suggested that the \"in tube\" SPME/LC-MS/MS employing the MIP extractive phase is suitable to determine AEA in plasma samples (AU)

FAPESP's process: 13/03808-9 - Development of extraction phase material restricted to microextraction packed sorbent drug in plasma samples and analysis by liquid chromatography coupled to mass spectrometry sequence
Grantee:Mônia Aparecida Lemos Pinto de Melo
Support Opportunities: Scholarships in Brazil - Doctorate