Adsorptive stripping voltammetric determination of antihypertensive agent: diltiazem

A novel potentiometric sensor based on ZnO decorated polyaniline/coal nanocomposite for diltiazem determination

Diltiazem (DTZ) is one of the most effective medications for treating cardiovascular diseases. It has been widely used for the treatment of angina pectoris, hypertension and some types of arrhythmia. The development and application of a modified carbon paste sensor with improved detection limits for the potentiometric determination of diltiazem are the main goals of the current study. Sensitivity, long-term stability, reproducibility and improving the electrochemical performance are among the characteristics that have undergone careful examination. A modified carbon paste sensor based on β-cyclodextrin (β-CD) as ionophore, a lipophilic anionic additive (NaTPB) and a ZnO-decorated polyaniline/coal nanocomposite (ZnO@PANI/C) dissolved in dibutyl phthalate plasticizer, exhibited the best performance and Nernstian slope. The ZnO@PANI/C based sensor succeeded in lowering the detection limit to 5.0 × 10-7 through the linear range 1.0 × 10-6 to 1.0 × 10-2 mol L-1 with fast response time ≤ 10.0 s. The prepared nanomaterial was characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The surface properties of the proposed sensor were characterized by electrochemical impedance spectroscopy (EIS). The selectivity behavior of the investigated sensor was tested against a drug with similar chemical structure and biologically important blood electrolytes (Na+, K+, Mg2+, and Ca2+). The proposed analytical method was applied for DTZ analysis in pure drug, pharmaceutical products and industrial water samples with excellent recovery data.

Fabrication of a sensitive sensor for electrochemical detection of diltiazem in presence of methyldopa

Diltiazem (DTZ) is one of the most important drugs in blood pressure that is used to treat cardiovascular diseases. With this overuse of this drug and its use for suicide, swelling and neck cramps and fever has made it important to measure it. So, this paper will give an account of modification of carbon paste electrode with the ternary-nanocomposite including reduced-graphene oxide (rGO), cadmium oxide and 1-ethyl 3- methyl imidazole chloride as ionic liquid for using the determination of DTZ in blood serum samples. Characterization of the synthesized rGO, cadmium oxide, and modified electrodes and their electrochemical performance were studied by, scanning electron microscopy, and X-ray diffraction, electrochemical impedance spectroscopy, and voltammetry technique. The improvement of the DTZ oxidation current by modified electrode originated from the increased electrode surface area. The optimized method was validated and the results showed that LOD = 3 nM and good linearity. Also, a linear concentration range of 0.01-150 μM with a LOD of 0.03 μM in presence methyldopa were achieved based on the electrochemical investigations. The prepared sensor showed good repeatability (RSD = 2.26%) and selectivity for DTZ determination in the real samples (relative recovery of 93-102%).

Green fabrication of 3D hierarchical blossom-like hybrid of peeled montmorillonite-ZnO for in-vitro electrochemical sensing of diltiazem hydrochloride drug

Herein, a 3D hierarchical blossom-like of Montmorillonite-ZnO (MMt/ZnO) micro-hybrids modified sensors have been successfully fabricated as an extraordinarily electrochemical sensor for detecting of the Diltiazem hydrochloride (DZM.HCl). The 3D hierarchical blossom-like of ZnO and series of MMt/ZnO hybrids have been synthesized using different contents of MMt [FMZ_1-5] via a hydrogel polymer template method using alginate ions. The effect of incorporation of different contents of MMt on the morphology, surface area of hybrids were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET) surface area method, and High-resolution transmission electron microscopy (HR-TEM). The obtained hybrid [FMZ₃] with 2.0% of MMt presented the most perfect blossom-like morphology and the highest surface area (190.06 m²/g) with the lowest resistivity. The hierarchical structure of [FMZ₃] reveals nanospheres of ZnO with an average diameter of 5.49 nm, which are assembled into nanorods followed by assembling to form a blossom-like shape with the inclusion of MMt peeled layers inside the rod with d-spacing ranges from 1.1-7.4 nm. Meanwhile, the implemented modified sensor 1.0% [FMZ₃] CPS retained excellent conductivity and electrocatalytic activity as appraised from the cyclic voltammetry (CV) measurements. Consequently, the electrochemical behavior and the oxidation mechanism of DZM.HCl drug has been investigated at the surface of the constructed sensor. Under the optimum operational conditions, the proposed sensor was successfully achieved detection limits 0.177, and 0.21 nmol·L^-1 of DZM.HCl in a commercial and human biological fluid (Serum samples), respectively. The constructed sensor accomplished an appropriate accuracy and free of obstruction from other ordinarily drug excipients.

Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

A simple method was developed for determining microquantities of diltiazem, based on the reduction of copper(II) in buffered solution (pH 7.0) and the use of a micellar medium containing 4,4′-dicarboxy-2,2′-biquinoline acid. The copper(I) produced reacts with 4,4′-dicarboxy-2,2′-biquinoline acid and the complexes formed are spectrophotometrically measured at 558 nm. A typical calibration graph shows good linearity (r = 0.993) from 20 to 100 μg mL–1 of diltiazem. The limit of detection and relative standard deviation were calculated as 12 μg mL–1 (99% confidence level) and 3.5% (40 μg mL–1; n = 6), respectively, with a mean recovery value of 96.5% found in pharmaceutical dosages. A straightforward and effective way to recycle the reagents is addressed. The hazardous aspects of the Cu(I)–BCA reaction are presented as well.

Determination of verapamil by adsorptive stripping voltammetry in urine and pharmaceutical formulations

A sensitive reduction peak of verapamil is obtained by adsorptive stripping voltammetry in 0.01 M phosphate (pH 7.4) at an accumulation time of 30 s. The peak potential is -1.81 V (vs. Ag/AgCl). The peak current is directly proportional to the concentration of verapamil (1x10(-8)-1x10(-6) M), with a 3sigma detection limit of 5x10(-10) M (0.246 ng/ml). The R.S.D. at the 1x10(-7) M level is 1.8%. The interference of some metal ions, and some amino acids, and the application of the method to analysis of urine, and pharmaceutical formulations are described. The method is simple (no extraction), rapid (30 s accumulation time), sensitive (the detection limit of verapamil is 0.491 ng/ml), reproducible(within day R.S.D. of 1.28-1.8%), and suitable for routine analysis of verapamil, urine, and pharmaceutical formulation.