Development of a method for the determination of apixaban in blood plasma using the stripping voltammetry method

Background. As is known, the issue of maintaining a balance between the efficacy and safety of anticoagulant therapy in patients with atrial fibrillation causes a number of difficulties in real clinical practice. In recent years, the development and clinical validation of sensitive and selective methods for quantitative determination of direct oral anticoagulant levels in the blood have demonstrated their relevance for optimizing drug monitoring in patient groups at increased risk of thromboembolic and hemorrhagic complications.
Objective: To develop a method for determining the concentration of apixaban (APX) in peripheral blood using a voltammetric sensor based on phenyl-modified graphite.
Materials and methods. The experimental basis of this study was the development of a new method for modifying a graphite electrode for the voltammetric determination of APX using domestic equipment and readily available reagents. A graphite electrode modified with phenyl groups using arenediazonium tosylates was used. The degree of modification was monitored instrumentally. The electrode surface was characterized using the ζ-potential (streaming potential) method. Electrode process characteristics (adsorption stage, electron fraction in the rate-limiting stage, and the αn factor) were determined using voltammetric peak shape analysis and the Laviron equation. Operating conditions for APX determination were selected.
Results. It was established that the anodic oxidation of APX on the surface of phenylated graphite is adsorption-based. The αn factors were calculated for the rate-limiting step (≈1.5) and for the overall electrode process (≈2). The flow potential method revealed an increase in the cathodic ζ-potential of the modified electrode, indicating an increase in its adsorption capacity. The following parameters were selected: analyte accumulation conditions; voltammogram recording mode; background electrolyte composition.
Conclusion. A new method for modifying a graphite electrode has been developed, enabling reliable monitoring of its properties. The modification has been shown to increase the surface’s adsorption capacity for APX. Operating parameters for its voltammetric determination have been selected. The method utilizes domestically produced equipment and readily available reagents, making it promising for clinical monitoring of anticoagulant therapy.

For citation: Dragunova MA, Slepchenko GB, Terra YuR, Moiseeva ES, Sitkova ES, Batalov RE. Development of a method for the determination of apixaban in blood plasma using the stripping voltam­metry method. Therapy (Moscow). 2026;12(5S):5–9.
https://dx.doi.org/10.18565/therapy.2026.5-s5.5-9

INTRODUCTION

Current guidelines for the diagnosis and management of atrial fibrillation (AF) recommend the AF-CARE pathway for every patient: C, comorbidity and risk factor management; A, avoidance of stroke and thromboembolism; R, reduction of symptoms through rate and rhythm control; and E, evaluation and reassessment [1]. Prevention of thromboembolic complications is therefore a central component of optimal anticoagulant therapy and directly affects patients’ life expectancy and quality of life [1].

Although antithrombotic management of AF is now well established, residual thromboembolic risk remains. Direct oral anticoagulants (DOACs) are preferred to vitamin K antagonists for preventing thromboembolic events in patients with nonvalvular AF [1, 2]. Data from international registries – including the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation, the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation, the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II, and the European Cardioversion Registry – show that DOAC use in AF has increased steadily [3, 4]. Randomized clinical trials have shown that anticoagulant therapy reduces the risk of ischemic stroke and other embolic events by approximately two-thirds, irrespective of baseline risk [5–7]. Nevertheless, studies of patients with AF who underwent transesophageal echocardiography while receiving DOACs have reported left atrial appendage (LAA) thrombosis in 2.5–3.0% of cases [7, 8]. In randomized clinical trials, stroke and peripheral thromboembolism occurred at annual rates of 1.11–2.4% despite regular anticoagulant use [9–11]. These findings indicate that some patients remain at risk of intracardiac thrombosis despite anticoagulation [12].

Furthermore, at least 2% of patients with AF receiving anticoagulant therapy experience major bleeding each year [13]. Maintaining an appropriate balance between efficacy and safety therefore remains essential and depends in part on achieving optimal drug exposure.

Therapeutic drug concentrations and individualized dosing are particularly important in patients at the extremes of body weight and in those with renal or hepatic impairment.

Existing methods for measuring anticoagulant concentrations, including high-performance liquid chromatography and chromogenic anti-factor Xa assays, require lengthy, complex sample preparation and expensive equipment and reagents, precluding real-time bedside testing.

Recent studies have reported promising electrochemical sensors for several DOACs used in clinical practice. Apixaban has been quantified in pharmaceutical formulations and biological samples using sensors modified with multiwalled carbon nanotubes [14] or, more commonly, metal nanoparticles such as gold, platinum, and bismuth [15].

Developing and clinically validating sensitive, selective methods for quantifying DOAC concentrations in blood is therefore relevant to therapeutic drug monitoring in patients at increased risk of thromboembolic or hemorrhagic complications.

The aim of this study is to develop a method for determining the concentration of apixaban in peripheral blood using a voltammetric sensor based on ph...

M.A. Dragunova, G.B. Slepchenko, Yu.R. Terra, E.S. Moiseeva, E.S. Sitkova, R.E. Batalov