Study on the Adsorption Properties of the Drug Mitomycin C by Stripping Voltammetry

Abstract

The adsorption of the antineoplastic drug mitomycin C (MC) on the hanging mercury drop electrode (HMDE) surface by means of stripping voltammetry measurements is studied. With this technique, a cathodic peak is obtained at −0.47 V (vs Ag/AgCl) in phosphate buffer pH 7.1 after accumulation onto HMDE surface by applying −0.35 V. Peak current variations with the accumulation time, MC concentration, and temperature are presented. The Langmuir isotherm is employed for adjusting the experimental results, and the values of the Gibbs free energy, enthalpy, and entropy of adsorption are calculated, the adsorption process being entropically governed. The results and data presented can provide useful information on the mechanism of penetration across the cellular membrane, which is of clinical interest since MC exerts its antineoplastic activity by interaction with biological membranes.

Interfacial thermodynamics of gallic acid adsorption on a chargeable hydrophobic surface

“…Before proceeding to a more detailed analysis, we notice that this temperature-dependent trend for GA is opposite to that previously observed for adsorption of dithiocarbamate pesticides onto the Hg-surface [23]. Moreover, similar decrease has been observed for mitomycin [18] and imidacloprid [19].…”

“…For the theoretical analysis of the interfacial adsorption, two types of adsorption isotherms were tested [5,18]: (a) Langmuir isotherm: the foundation of the Langmuir isotherm assumes that the adsorption takes place on fixed homogenous absorption sites, of equal energy, forming a monolayer surface coverage, with no interactions between adsorbed molecules. (b) The Frumkin isotherm: acording to the suggested adsorption mechanism as described by the surface reactions (Eq.…”

“…These studies revealed some unexpected trends. For example, in the case of mitomycin-C [18] and imidacloprid [19], it was found that the adsorption process could be described by the Langmuir isotherm, while in the case of DTC, the adsorption process was described by the Frumkin isotherm, e.g., due to the lateral interactions between neighbouring adsorbed DTC molecules [23].…”

“…More specifically, it has been demonstrated that the thermodynamic parameters of the adsorption of organics, on HMDE, can be measured experimentally by temperature-dependent stripping voltammetry (TD-SV). This method has been applied to study the interfacial adsorption thermodynamics of mitomycin-C(MC) [18], imidacloprid [19] and dithiocarbamate pesticides (DTC) [23]. These studies revealed some unexpected trends.…”

“…The hanging mercury drop electrode (HMDE) has been used as a model surface for the physicochemical study of adsorption of hydrophobic molecules [15][16][17]. In a recent work, the HMDE was used as a model surface for the cell membrane with regard to the surface activity of the adsorption of the drug mitomycin [18] and imidacloprid insecticide [19,20]. Also, HMDE was previously used to understand the mechanism of reduction and SAS bond breaking in proteins [21,22], dithiocarbamate pesticides in [23] and cysteine [24,25].…”