Silica-gel incorporated carbon paste sensor for the electrocatalytic oxidation of famotidine and its application in biological sample analysis

Abstract

Famotidine (FAM) is an efficacious competitive drug, and a reversible inhibitor of H2-histaminergic receptor action used to manage acid production in the stomach. Among the elderly population, this drug poses the risk of kidney failure and impaired mental health conditions. Additionally, FAM is an environmental contaminant. Thus, FAM quantification was undertaken in urine and tablet dosage forms utilizing an uncomplicated, inexpensive, silica-gel blended carbon paste electrode (SG/CPE) as an electrochemical sensor. In contrast to bare CPE, the existence of the modifier effectively enhanced the oxidation peak current for FAM. The impact of diversified factors such as time of accumulation, pH, sweep rate, and concentration variation was examined. Phosphate buffer solution (0.2 M) was employed for electro-oxidation of FAM, and the optimum results were obtained at pH 3.0. The overall reaction at the sensing platform was under diffusion control with the involvement of a single electron transfer. The estimated heterogeneous rate constant (k°) was 3.493 × 103 s–1. Using the calibration curve, the calculated limit of detection (LOD) and limit of quantification (LOQ) were 11.72 × 10–8 M and 39.06 × 10–8 M, respectively. Among a variety of common interferents, the sensor demonstrated exceptional discrimination capabilities. Thus the proposed sensing platform displayed adequate sensitivity, selectivity, stability, reproducibility, and repeatability. Satisfactory recoveries were achieved for FAM in spiked human urine (91.40–97.50%) and tablet dosage forms (90.33–96.70 %), attesting the SG/CPE as a promising candidate for real-time analysis. Novelty Statement: Silica gel/CPE as an electrochemical sensing platform exhibited remarkable electrocatalytic activity together with high sensitivity and selectivity for the quantitative determination of Famotidine (FAM). The developed method was validated by evaluating the accuracy, precision, stability, and anti-interference properties. The lowest detection limit of 11.72 × 10–8 M was achieved, and the analytical advantage of the sensor is the quick quantification of FAM in pharmaceutical preparations and biological fluids.