Electroreduction of dipyridamole at mercury-coated platinum microelectrode

Abstract

A eletrorredução do Dipiridamol (DIP) foi estudada em solução tampão fosfato 0,10 mol L -1 (pH 3,0) em microeletrodo de platina coberto com mercúrio eletrodepositado (Hg-ME), empregando as técnicas de voltametria cíclica, de varredura linear e polarografia. A similaridade entre o perfil voltamétrico obtido com Hg-ME e as ondas polarográficas sigmoidais com correntes limitadas por difusão é demonstrada. Experimentos com eletrodo de gota pendente de mercúrio (HMDE) foram realizados em paralelo para confirmar os resultados obtidos com Hg-ME, os quais indicaram que a reação de redução ocorre em duas etapas irreversíveis com o consumo de dois elétrons e dois prótons por etapa. A corrente limite de difusão, referente à primeira etapa de redução, permitiu estimar o coeficiente de difusão do DIP como sendo igual a 2,04 x 10 -5 cm 2 s -1 .The electroreduction of Dipyridamole (DIP) was studied in 0.10 mol L -1 phosphate buffer solution (pH 3.0) on a mercury coated platinum microelectrode (Hg-ME), employing cyclic, linear sweep voltammetry and polarography techniques. The similarity between Hg-ME voltammetric profile and the sigmoidal polarographic waves both with a diffusion limited current is showed. Experiments with a hanging mercury drop electrode (HMDE) were performed in parallel to confirm the results obtained with Hg-ME, which indicated that the reduction occurs in two irreversible steps involving two electrons and two protons each step. The limiting diffusion current, concerning the first step, allows estimating the diffusion coefficient for DIP as being equal to 2.04 x 10 -5 cm 2 s -1 .

Determination of dipyridamole in pharmaceutical preparations using square wave voltammetry

“…(1). As the number of electrons transferred in each step is known (n = 2) [22], the transfer coefficient for both stages could be estimated as being equal to 0.56 and 0.55.…”

Novel voltammetric investigation of dipyridamole at a disposable pencil graphiteelectrode

“…Dipyridamole (DIP), known also as Persantin (2,6-bis (diethanolamino)-4,8-dipiperidinopyrimido [5,4-d] pyrimidine) (Figure 1), is a coronary vasodilator and antiplatelet drug introduced in 1959 in Germany [1]. To date, it has been used for the treatment of cardiovascular diseases like angina pectoris and myocardial infarction [2], its antioxidant properties being important for antithrombotic and vasodilatory activity.…”

“…Moreover, study of the voltammetric behavior of DIP in different conditions can give insight into similar redox processes taking place in living organisms explaining thus, at least partially, their action mechanism [3,11]. DIP's electrochemical (cathodic [1] and anodic [2,3,27,28]) behavior was investigated in aqueous [1,27], micellar [28], and nonaqueous media [2,3] at different electrodes, e.g., Pd [3], Pt [2,3,27], mercury-coated platinum microelectrode [1], glassy carbon, and graphite [28]. On the other hand, there are few literature reports related to voltammetric methods developed for DIP quantification in pharmaceutical [14,[29][30][31] and biological samples [14,15,31,32].…”