Nano Determination of KinaseInhibitor Sorafenib Drug in Pharmaceutical Formulation and Human Blood at a Modified Carbon Paste Electrode

Abstract

Sorafenib (SORA) has clinical activity against several tumor types. Carbon paste electrode modified with natural sodium montmorillonite clay (Na-MMT/CPE) was used as a sensor for sensitive and selective determination of SORA drug using square-wave adsorptive anodic stripping voltammetry (SW-AdASV). Unmodified CPE as well as the modified one were characterized using scan electron microscopy (SEM), N2 sorption isotherms (BET) and electrochemical impedance spectra (EIS). In spite of the very low conductivity of Na-MMT, a shift in the peak potential to less positive and about two times enhancement in the peak current were observed at 5% (w/w) Na-MMT/CPE compared to that at bare CPE, reflecting electrocatalytic activity of Na-MMT toward oxidation of SORA. This may be attributed to strong adsorptive property of Na-MMT due to its high surface area or specific bonding reactions of SORA with the functional groups at the edges of clay sheets. The method was employed successfully to determine SORA in its pharmaceutical formulation (Nexavar tablets). Detection limit of 1.5 × 10−10 M was also achieved in human serum. The described method is reliable, simple and sensitive enough for assay of SORA in real plasma samples, pharmacokinetic studies, quality control and assurance of the drug in industry and in clinical laboratories.

Quantification of Chloroxylenol, a Potent Antimicrobial Agent in Various Formulations and Water Samples: Environmental Friendly Electrochemical Sensor Based on Microwave Synthesis of Graphene

“…Apparatus for voltammetric, EIS and FTIR measurements are as described in our previous work. 12 Chromatographic measurements were performed using HPLC pump (Bischoff, Switzerland), UV-vis detector (Bischoff Lambda 1000), reversed phase column (Prontosil C18, 250 × 4.0 mm, 5 μm), Rheodyne 7125 injector valve and Bischoff McDAcq integrator software v1.5.…”

“…Preparation of bare and carbon paste modified electrodes.-This is done as described in our previous work. 12 Briefly, the carbon paste was first prepared via uniformly grinding of 5 g of graphite powder with 1.8 mL Nujol oil (Sigma, d = 0.84 g mL −1 ). A piece of this carbon paste was tightly packed into the electrode cavity (The working electrode body (BASi Model MF-2010) is a Teflon rod with end cavity of 3 mm diameter and 5 mm deep and the contact was made via a fixed Cu wire in the center of this rod).…”

“…So, the values of αn a were calculated as 0.77 to 1.07. The number of electrons (n a ) and protons (p a ) involved in the rate-determining step were estimated 12,70 to be two (at the probable values of α of 0.39 to 0.54) and one, respectively, according to the following equations: E p (V)/ log v mVs −1 = 0.059/αn a ( E p (V))/ pH = (0.059/αn a ) p a , Interfacial adsorptive behavior of chloroxylenol at the electrodes surface.-The adsorption character of Chloroxylenol onto the bare CPE and 0.4%(w/w) GR/CPE surfaces was investigated via the proportional of the peak current i p with the scan rate v according to the following equation for an adsorption-controlled reaction: 62,71 i p = n 2 F 2 A o /4RT v Where, • (mol cm −2 ) is the amount of analyte adsorbed onto surface of the electrode.…”

“…Metal complexes, nanomaterials, polymers and organic compounds have been reported as the effective modifiers for solid electrodes. [9][10][11][12] Nanomaterials development in electrochemical sensors has been widely used in chemicals sensing, electronics, biotechnology, biomedical and bioanalytical applications.…”

A First Efficient Voltammetric Approach for Detection of Octreotide, an Octapeptide Analogue of Somatostatin Natural Hormone, in Sandostatin Intramuscular Injection and Human Plasma Based on Modification Free Electrochemical Sensor

“…The surface structure shows also that the graphite particles are covered by a thin film of oil (pasting liquid) which gives rise to the hydrophobic character of CPE surface. Although such pasting liquids are non-conducting and exhibit high chemical and electrochemical inertness, some sources quote that the hydrophobicity of graphite 31 and layer pasting liquid 32 at the CPE surface may promote the adsorption of many lipophilic/hydrophobic molecules. 32,33 SEM image brings to light also the heterogeneity (composite character) 34 of CPE which can control the type of adsorption equilibrium of OCT at electrode surface as discuss later.…”