Imunossensor impedimétrico para determinação de rituximabe aplicado ao controle qualidade e monitoramento clínico
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2023-02-10
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Universidade Federal de Goiás
Resumo
Introduction: Cancer is an umbrella term for a large group of diseases that can affect any part of
the body. Rituximab (RTX) is a chimeric monoclonal antibody (mAb) formed by the mouse/human
combination, which specifically binds to the CD20 cell marker that is expressed in normal and
malignant B lymphocytes, exerting significant antitumor activity. In this context, RTX emerged as a
therapeutic alternative in the treatment of various pathologies, including autoimmune diseases,
inflammatory diseases and various types of cancer in which sensitive and low-cost methods are
required for therapeutic drug monitoring (TDM) and quality control (QC) of this drug. Objectives:
To develop a selective electrochemical immunosensor for the detection and quantification of RTX
in urine and blood. Methodology: The ploliconal antibody (pAb) was purified from chicken egg,
used as a biorecognition element to create an immunosensor for the detection and quantification of
RTX. The immunosensor was constructed from the immobilization of the RTX IgY antibody on the
glassy carbon electrode surfaces. The characterization of the immunosensor was obtained through
monitoring at each stage via cyclic voltammetry and electrochemical impedance spectroscopy,
where selectivity is obtained by specifically binding pAb and RTX and casein is used to block
possible nonspecific interactions of other proteins. After the development of the immunosensor, the
validation of the method was carried out, evaluating the selectivity, accuracy, precision, linearity
and limits of detection (LOD) and quantification (LOQ). Finally, the RTX was determined in urine
and blood samples. Results and discussion: Linearity was demonstrated between charge
transfer resistance and RTX from 2 to 14 μg mL−1 (r2 of 0.99), with LOD and LOQ of 130 and 400
ng mL−1 respectively. The method showed adequate precision with a RPD of 0.96% for
researcher 1 and 1.27% for researcher 2, and accuracy with a RPD of 1.30%, with a confidence
interval between 99.0% and 101.0 %. Selectivity was achieved by demonstrating the binding
specificity between the antibody and RTX, where casein blocks non-specific binding when the
immunosensor is applied to blood and urine samples. Conclusion: The developed immunosensor
presented precision and accuracy for the detection of RTX with results in approximately 20
minutes. In this way, low-cost, marker-sensitive electrochemical immunosensors can help in TDM,
QC and extended stability monitoring of different drugs, in a simple way and with versatile assays.
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RODRIGUES, E. S. B. Imunossensor impedimétrico para determinação de rituximabe aplicado ao controle qualidade e monitoramento clínico. 2023. 58 f. Tese (Doutorado em Ciências Farmacêuticas) - Universidade Federal de Goiás, Goiânia, 2023.