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A Sensitive Electrochemical Sensor Based on Calix[n]arene-Modified PGE for the Determination of Tofacitinib in Human
Tugba Sardohan Koseoglu1, Aykut Yalabik1,2, Hasan Koseoglu3
1Isparta University of Applied Sciences, Faculty of Technology, Department of Biomedical Engineering, Isparta 32100, Turkey.
Abstract:
Tofacitinib is a potent Janus kinase inhibitor widely used in the treatment of various autoimmune diseases, including rheumatoid arthritis and psoriasis. Monitoring its concentration is vital for therapeutic efficacy and safety. In this study, a novel, rapid, and highly sensitive electrochemical sensing platform was developed for tofacitinib determination using pencil graphite electrodes (PGEs) modified with polypyrrole (PPy) and calix-[n]-arene derivatives. The modified electrodes were prepared via cyclic voltammetry (CV) by incorporating three different macrocycles: calix[4]-arene, calix[6]-arene, and calix[8]-arene. Surface characterization was performed using Scanning Electron Microscopy (SEM) and SEM-EDS. Under optimized conditions (Britton-Robinson buffer at pH 4.0, 5 polymerization cycles, and 0.005 M modifier concentration), tofacitinib was quantified using differential pulse voltammetry (DPV). The linear calibration ranges were established as 0.10-0.80 ppm for calix[4]-arene and calix[6]-arene, and 0.10-0.60 ppm for calix[8]-arene. The limits of detection (LOD) were found to be 0.0275, 0.0212, and 0.0184 ppm for calix[4], [6], and [8] derivatives, respectively, demonstrating a clear correlation between macrocyclic cavity size and analytical sensitivity. The proposed sensor exhibited excellent selectivity in the presence of common interferents like ascorbic acid, caffeine, and glucose. Furthermore, the practical applicability of the method was validated in pharmaceutical formulations and human urine samples, yielding satisfactory recovery values between 98.0% and 101.5%. This study provides a cost-effective and disposable alternative to sophisticated chromatographic methods for routine clinical analysis.
Insights
A new electrochemical sensor using modified pencil graphite electrodes offers a rapid, sensitive, and cost-effective method for monitoring tofacitinib (a Janus kinase inhibitor) in clinical samples.
Area of Science:
- Electrochemistry
- Analytical Chemistry
- Materials Science
Background:
- Tofacitinib is a crucial Janus kinase inhibitor for autoimmune diseases.
- Therapeutic drug monitoring of tofacitinib is essential for patient safety and efficacy.
- Existing methods for tofacitinib analysis can be complex and costly.
Purpose of the Study:
- To develop a novel, rapid, and sensitive electrochemical sensing platform for tofacitinib determination.
- To utilize polypyrrole (PPy) and calix-[n]-arene derivatives for modifying pencil graphite electrodes (PGEs).
- To evaluate the sensor's performance in pharmaceutical formulations and biological samples.
Main Methods:
- Fabrication of PGEs modified with PPy and calix-[n]-arene derivatives (calix[4], [6], [8]) via cyclic voltammetry (CV).
- Surface characterization using Scanning Electron Microscopy (SEM) and SEM-EDS.
- Quantification of tofacitinib using differential pulse voltammetry (DPV) under optimized conditions.
Main Results:
- The sensor demonstrated high sensitivity with limits of detection (LOD) as low as 0.0184 ppm.
- Linear calibration ranges were established for different calixarene derivatives.
- The sensor showed excellent selectivity against common interferents and high recovery rates (98.0-101.5%) in real samples.
Conclusions:
- The developed electrochemical sensor provides a sensitive, selective, and cost-effective method for tofacitinib quantification.
- The sensor's performance correlates with the macrocyclic cavity size of the calixarene derivatives.
- This disposable sensor is a viable alternative to chromatographic methods for routine clinical analysis.
