Screen-printed electrode for electrochemical detection of sunitinib malate for therapeutic drug monitoring

Sunitinib is a targeted therapy for colorectal cancer, which needs a precise dosage due to potential severe side effects from overdose. Therapeutic drug monitoring is crucial for maintaining optimal drug levels in body fluids. Traditional anticancer drug dose evalua­tion methods such as high-pressure liquid chromatography, liquid chromatography with mass spectrophotometry, and immunoassays are cumbersome. This study explores the utilization of electrochemical sensors on indigenously developed screen-printed electrodes for sunitinib malate monitoring. Differential pulse voltammetry, cyclic voltam­metry and chrono-amperometric studies were conducted in a conventional three-elec­trode system. An anodic peak current, indicative of sunitinib malate electro­oxi­dation, was observed around +0.45 V vs. Ag/AgCl reference electrode in 0.1 M PB of pH 7.4. Sen­sitivity, the limit of detection and method detection limit were determined as 0.386 µA µM-1 cm-2, 0.009 and 0.0108 µM, respectively. The response exhibited linearity (R2 = 0.990) with sunitinib concentration ranging from 0.08 to 88 μM with good reproducibility. DPV studies on real samples yielded acceptable recovery values. Electro­chemical sensors based on the screen-printed electrode present a promising approach for sunitinib monitoring, offering sensitivity, low limit of detection, and a wide linear range. Since the expected plasma concentration of sunitinib is much higher than the sensor detection range, it can be used for real sample analysis. Here developed methods could simplify and improve therapeutic drug monitoring in colorectal cancer treatment.