Comparative study of boron-doped diamond, basal-plane pyrolytic graphite, and graphite flake paste electrodes for the voltammetric determination of rivaroxaban and dabigatran etexilate in pharmaceuticals and urine samples

As anticoagulants, rivaroxaban (RIV) and dabigatran etexilate (DAB) are high-risk drugs that can cause lifethreatening bleeding. They are a group of drugs that require optimal dosing, therefore their monitoring in the patient is of great importance, especially in emergencies. In this study, we developed a rapid, sensitive squarewave voltammetric (SWV) method by using boron-doped diamond, graphite flake paste, and basal-plane pyrolytic graphite electrodes (BDDE, GFPE, and BPPGE, respectively) to determine the presence of anticoagulants, namely, RIV and DAB in pharmaceutical and urine samples. The supporting electrolyte composition and SWV parameters were investigated. The sensitivity, stability, recovery, calibration curve, and limit of detection (LOD) of the developed method were evaluated. Under the optimal experimental condition, a wider linear response was achieved using BDDE in the detection of both RIV and DAB. The calibration curve for RIV was in the range of 0.5-30.0 mu mol L-1 for BDDE and 1.0-10.0 mu mol L-1 for GFPE. The calibration curve for DAB was in the range of 0.01-0.7 mu mol L-1 for BDDE and 0.07-1.0 mu mol L-1 for BPPGE, which shows a linear relationship between the concentration of DAB and the anodic current. LOD was equal to 0.145 mu mol L-1 (for RIV at BDDE), 0.297 mu mol L-1 (for RIV at GFPE), 2.78 nmol L-1 (for DAB at BDDE), and 16.7 nmol L-1 (for DAB at BPPGE). Finally, BDDE, GFPE, and BPPGE were applied to detect the presence of RIV and DAB in pharmaceuticals and spiked urine samples with satisfactory results (98.2-100.5% for RIV and 99.22-102.8% for DAB). Cyclic voltammetry (CV) was applied to understand the electrode mechanism of RIV and DAB oxidation. The character of RIV and DAB signals was irreversible and diffusion-controlled. In addition, the roughness factor (RF) of BDDE, GFPE, and BPPGE was investigated, which were equal to 0.367, 0.558, and 0.422, respectively.

Automated summary

In this study, a rapid and sensitive squarewave voltammetric method was developed using boron-doped diamond, graphite flake paste, and basal-plane pyrolytic graphite electrodes to detect the presence of anticoagulants, namely, rivaroxaban and dabigatran etexilate, in pharmaceutical and urine samples. The method showed satisfactory sensitivity, stability, recovery, calibration curve, and limit of detection. The electrode mechanism of oxidation for these anticoagulants was understanding using cyclic voltammetry, showing irreversible and diffusion-controlled signals. The roughness factor for the different electrodes was also investigated.