Determination of efavirenz in diluted alkaline electrolyte by cathodic adsorptive stripping voltammetry at the mercury film electrode

Abstract

Um método de redissolução para a determinação do agente anti-retroviral efavirenz em concentrações submicromolares e meio eletrolítico alcalino diluído é descrito. As condições experimentais ótimas encontradas são: NaOH 2,0 × 10 -3 mol L -1, potencial de acumulação −0,10 V, amplitude de pulso 50 mV e velocidade de varredura 50 mV s ). As condições mais convenientes para a medida da concentração de efavirenz na presença de ATP, DNA, diversos metais e outros antivirais foi também investigada. A utilidade do método é demonstrada pela determinação de efavirenz em uma mistura sintética contendo lamivudina e zidovudina, drogas frequentemente usadas na clínica em associação com o efavirenz como parte da terapêutica anti-retroviral de alta ação (HAART).A stripping method for the determination of the antiretroviral drug efavirenz at the submicromolar concentration levels in diluted alkaline electrolyte is described. Optimum experimental conditions were: 2.0 × 10 -3 mol L -1 NaOH, accumulation potential of −0.10 V, pulse amplitude of 50 mV and scan rate of 50 mV s ). The most convenient conditions to measure the efavirenz concentration in the presence of ATP, DNA, several metals, and other antiviral drugs was also investigated. The utility of the method is demonstrated by the determination of efavirenz in a synthetic mixture containing both lamivudine and zidovudine, which are frequently used in the clinic in association with efavirenz as part of highly active antiretroviral therapy (HAART).

Determination of Hypoxanthine in the Presence of Copper by Adsorptive Stripping Voltammetry

“…Eight successive measurements (using 30 s accumulation times at -0.50 V; final potential at −1.1 V; 60 s condition times at −0.9 V; scan rate, 200 mV·s −1 and 1.0 × 10 −3 mol·L −1 of NaOH as supporting electrolyte ) yielded a mean peak current of 8453 ± 97 nA and a range of 8312 -8625 nA. Such precision compares favorably with that reported for other compounds measured by adsorptive stripping analysis [28] [29]. Figure 4 shows linear CV voltammograms for solutions of increasing hypoxanthine concentration (steps of 10 ppb), in the presence of 0.50 ppm copper (II), after 120 s of accumulation time at −0.5 V. Well-defined stripping peaks were observed over this concentration range.…”

Ultratrace Determination of the Antiretroviral Drug Lamivudine in Diluted Alkaline Electrolyte by Adsorptive Stripping Voltammetry

“…Spectrophotometric (6)(7)(8)(9), chromatographic [10][11][12][13][14][15][16] and electrochemistry (17)(18) analytical methods have been developed for the determination of lamivudine. As a result of advancements in properties of the adsorptive stripping voltammetry, new methodologies have been developed for adenine, thymine, guanine, ATP, DNA and antiretroviral drugs determinations, employing alkaline solution with lower ionic strength as the supporting electrolyte (19)(20)(21)(22)(23)(24)(25). Using this alkaline electrolyte, the present work found a new stripping voltammetric procedure for trace detection of lamivudine based on its adsorption at the thin film mercury electrode.…”

A Novel Hybrid Nano‐composite Grafted Electrochemically Reduced Graphene Oxide Based Sensor for Sensitive Determination of Efavirenz

“…The EFZ directly binds to the RT that causes a disruption of the enzyme's catalytic site, which hinders the formation of viral double‐stranded DNA from the single‐stranded viral RNA genome . EFZ is a first‐line drug and it is usually prescribed either in combination with protease inhibitor or nucleoside reverse‐transcriptase inhibitor for the management of the disease . EFZ is metabolized in human system into hydroxylated compounds by cytochrome P450 (CPY) with CYP2B6 and CYP2A4 being the major isozymes responsible for the biotransformation and excreted through the urine and feces.…”

“…Electrochemical techniques have been explored to overcome these difficulties as they are advantageous and provide high selectivity, sensitivity, convenient tool with fast response, reproducibility, and the analysis can be carried out without complicated sample pretreatment . However to the best of our knowledge, very scarce attempts have been made for the determination of EFZ by electrochemical methods . In these methods dsDNA or NiO nanoparticle modified glassy carbon electrodes were used and a very low linear dynamic range was observed.…”