Application of a Solid-State Potentiometric Sensor for Point-of-care Diagnostics of Flucloxacillin in Spiked Human Plasma; Whiteness Evaluation

Antibiotic resistance is a crisis that is escalating nowadays. Thus, therapeutic drug monitoring (TDM) is crucial to personalize the dose. Point-of-care (POC) devices are very effective in TDM where drug concentration can be easily and continuously monitored. This work describes for the first time the use of inexpensive, transportable, efficacious, and eco-friendly POC solid-state potentiometric sensor for the TDM of Flucloxacillin (FLU) in spiked plasma samples. This was achieved by using an innovative glassy carbon electrode modified with ion sensing membrane doped with carbon nanotubes. Optimization of the sensing membrane composition was performed using different plasticizers and by adding an ionophore. This was followed by doping the ion sensing membrane with carbon nanotubes which resulted in enhancing the sensor's sensitivity towards FLU. Over a concentration range from 1.0×10⁻⁵–1.0×10⁻² M FLU, a linear response was obtained with a slope of 56.6 mV/decade. Our proposed sensor has been validated according to IUPAC recommendations with acceptable results.

It was effectively employed for a selective determination of FLU in the presence of a co-formulated antibiotic (Amoxicillin), along with other excipients in the dosage form, and in spiked plasma samples, without any interference. The whiteness of the method was assessed, which proves the high greenness and superb functionality of our proposed method.