Voltammetric determination of leucovorin in pharmaceutical preparations using a boron-doped diamond electrode

Abstract

Method for voltammetric determination of leucovorin, a drug frequently applied to decrease some unfavorable effects of anticancer drugs such as methotrexate or to increase the therapeutic effect of 5-fluorouracil, has been developed employing a bare boron-doped diamond electrode. It is the first method for leucovorin determination based on its electrochemical oxidation. Although at least three anodic and three cathodic voltammetric peaks could be recorded under the used conditions, only the anodic response situated at about ? 900 mV (vs. saturated Ag|AgCl electrode) was suitable, namely due to its shape and position, for analytical purposes. Using differential pulse voltammetry with optimized parameters and supporting electrolyte of pH 3, the linear dynamic range of leucovorin determination was recorded from 0.15 to 25 lmol dm-3. Under such conditions, low limit of quantification of 0.050 lmol dm-3 and limit of detection of 0.015 lmol dm-3 as well was reached. Relative standard deviation calculated from 11 repeated measurements amounted to 0.7% and calculated from five repeated determinations amounting less than 3.0%. Applicability of the developed method was verified by repeated analysis of the pharmaceutical preparation with excellent results (recovery 98.7-102.8%, relative standard deviation 1.81%).

Towards voltammetric point of care detection of leucovorin

“…This has been shown to involve two electrons and two protons ultimately forming dehydrofolinic acid. 33 This proposed mechanism is based upon the oxidation of folic acid, and it is hypothesized that this follows a similar electrooxidation mechanism. 33 For CV, concentrations in excess of the therapeutic dosage typically used for patient treatments where utilized.…”

“…33 This proposed mechanism is based upon the oxidation of folic acid, and it is hypothesized that this follows a similar electrooxidation mechanism. 33 For CV, concentrations in excess of the therapeutic dosage typically used for patient treatments where utilized. Therefore, the utilization of SWV was undertaken.…”

“…Previous electrochemical studies exploring LV detection have utilized differential pulse voltammetry (DPV) 32 and electrochemiluminescence (ECL). 2,31,33 However, the DPV study did not explore its detection within complex biological matrices but focus on the electrochemistry analysis using different electrodes. While the ECL approach showcased a wide dynamic detection range and excellent limits of detection, it did exhibit specific limitations, primarily requiring an alkaline environment with a pH of 12 for optimal LV detection, restricting its practical clinical implementation due to pH constraints.…”

Analytical Applications of Electrochemically Pretreated Boron‐Doped Diamond Electrodes

“…The electrochemical activity is thus adjusted to attain, for example, a higher sensitivity and selectivity, besides a lower adsorption . In some instances, BDDEs have been used without any electrochemical pretreatments in the determination of different analytes, with satisfactory analytical results and good repeatability, e. g . However, in most such cases, since comparisons with the electrochemical signals from the same BDDEs when electrochemically pretreated were not reported at all, the question of whether better results could be attained with a CPT‐BDDE or an APT‐BDDE remains unanswered.…”

“…The electrochemical activity is thus adjusted to attain, for example, a higher sensitivity and selectivity, besides a lower adsorption. [19,107,118,119] In some instances, BDDEs have been used without any electrochemical pretreatments [118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133][134][135][136] in the determination of different analytes, with satisfactory analytical results and good repeatability, e. g. [120,126] However, in most such cases, since comparisons with the electrochemical signals from the same BDDEs when electrochemically pretreated were not reported at all, the question of whether better results could be attained with a CPT-BDDE or an APT-BDDE remains unanswered. In a few of those cases, [133][134][135][136] when a free-standing BDD was used, the BDDE was simply polished, as first done by Marken et al; [77] comparisons between the electrochemical activities for the respective analyte after different pretreatments (polish, PTA or PTC) were performed in two cases, [135,136] with better results after the polish procedure.…”