Oxidation Of Promethazine Research Articles

Determination of promethazine in forensic samples using multi-walled carbon nanotube-gold nanoparticle electrochemical sensor.

An electrochemical sensor was developed based on a glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) for the determination of promethazine (PMZ) in 'purple drank', pharmaceutical formulations, and synthetic saliva. The oxidation of PMZ at the modified electrode occurred at a higher cathodic potential and produced a higher sensitivity compared to the unmodified GCE. The morphology of the modified electrode was characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The presence of MWCNTs and AuNPs was confirmed. The optimized parameters included the concentration and pH of the supporting electrolyte, amount of modifiers used to fabricate the electrode, deposition potential, and time. Using these optimized conditions, the method has a linear range from 0.5 to 100 μmol L-1, with a R2 value of 0.9991. The limit of detection (3SDblank/slope) was 0.13 μmol L-1. The proposed electrochemical sensor was successfully applied for the determination of PMZ in 'purple drank', pharmaceutical formulations, and spiked synthetic saliva samples. The results obtained from this sensor were in statistical agreement with the values obtained using the reference gas chromatography-flame ionization method.

Subnanomolar detection of promethazine abuse using a gold nanoparticle-graphene nanoplatelet-modified electrode.

A simple, sensitive, and effective adsorptive stripping voltammetric sensor for the detection of trace-level promethazine was created based on a gold nanoparticle-graphene nanoplatelet-modified glassy carbon electrode (AuNP-GrNP/GCE). AuNP-GrNP nanocomposites were synthesized using an electroless deposition process, and the morphology was characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The electrochemical behavior and detection of promethazine at the AuNP-GrNP/GCE were investigated utilizing cyclic voltammetry and adsorptive stripping voltammetry. The AuNP-GrNP/GCE showed outstanding synergistic electrochemical activity for promethazine oxidation, a highly active surface area, great adsorptivity, and outstanding catalytic properties. The electrolyte pH, amount of AuNP-GrNP nanocomposite, preconcentration potential (vs. Ag/AgCl), and time were optimized to obtain a high performanceelectrochemical sensor. Under optimal conditions, the proposed sensor displayed two linear concentration ranges from 1.0nmolL-1 to 1.0μmolL-1 and from 1.0 to 10μmolL-1. The limits of detection and quantitation were 0.40 and 1.4nmolL-1, respectively. This sensor displayed high sensitivity, a capability for rapid analysis, and excellent repeatability and reproducibility. The developed sensor was effective and practical for promethazine detection in biological fluids and forensic samples, and the obtained results exhibited excellent agreement with the results obtained using the method described in the British Pharmacopoeia. Graphical abstract.

A portable optical colorimetric sensor for the determination of promethazine in lean cocktail and pharmaceutical doses

A low-cost, easy-to-use and portable optical colorimetric sensor determined promethazine using the oxidation of promethazine by a potassium persulfate reagent entrapped within a sol-gel polymer network. The colored reaction product was detected with a portable spectrometer. The surface morphology of the optical colorimetric sensor was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Under optimized conditions, the calibration curve of promethazine was a concentration range from 50 to 500 mg L−1 with a coefficient of determination (r2 = 0.9948). The limit of detection (LOD) and limit of quantification (LOQ) were 16.5 and 48.9 mg L−1, respectively. The intra-day precisions of the proposed method for measurement of promethazine at the concentrations of 80, 250 and 350 mg L−1 were 0.8, 4.3 and 2.4%RSD, respectively while the inter-day precisions were 1.9, 2.9 and 0.2%RSD, respectively. Accuracy of promethazine analysis ranged from 87 to 105%. The proposed device was stable for at least 90 days. The method was applied for the determination of promethazine in lean cocktail samples and pharmaceutical promethazine. The amounts of promethazine determined by the proposed method and amounts determined by spectrophotometry were not significantly different at 95% confidence level. The developed method is portable, inexpensive, easy and safe to use, consumes low amounts of sample and reagent and enables qualitative and quantitative analysis of the target analyte.

Electrochemical Sensor Based on Multiwall Carbon Nanotube-Paste Electrode for Determination of Promethazine in Pharmaceutical Formulations and Blood Plasma

A multi-walled carbon nanotube modified paste electrode (MWCN-PE) was used for determination of promethazine (PMZ) in drug formulations and blood plasma by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Results revealed that the MWCN-PE shows an electrocatalytic activity toward the anodic oxidation of PMZ by a marked enhancement in the current response in buffered solution at pH 5.0. At the MWCN/CPE, the anodic peak potential of PMZ was shifted by 28.0 mV to more negative potential in comparison with bare carbon paste electrode. The detection limit for this method was 0.025 µmol L-1. Results indicated that the modified electrode could be employed for the determination of promethazine hydrochloride in pharmaceutical formulations and plasma samples.

Portable system of programmable syringe pump with potentiometer for determination of promethazine in pharmaceutical applications

A simple and fast-automated method was developed and validated for the assay of promethazine hydrochloride in pharmaceutical formulations, based on the oxidation of promethazine by cerium in an acidic medium. A portable system, consisting of a programmable syringe pump connected to a potentiometer, was constructed. The developed change in potential during promethazine oxidation was monitored. The related optimum working conditions, such as supporting electrolyte concentration, cerium(IV) concentration and flow rate were optimized. The proposed method was successfully applied to pharmaceutical samples as well as synthetic ones. The obtained results were realized by the official British pharmacopoeia (BP) method and comparable results were obtained. The obtained t-value indicates no significant differences between the results of the proposed and BP methods, with the advantages of the proposed method being simple, sensitive and cost effective.

Spectrophotometric Determination of Metoclopramide in Some Pharmaceutical Preparation via Oxidative Coupling Reaction

the oxidation of promethazine by sodium hypochlorite and the coupling of the resulting product with metoclopraide in acetic acid medium to form a blue product with maximum absorption at 596 nm. Beer's law is obeyed over the concentration range of (3-30) gml,with molar absorptivity of 1.1104 L.mol-1.A relative standard deviation of the method was less than 1.2% and accuacy was 99.6% The optimum conditions for all colour development are described and the proposed method has been successfully applied for the determination of metoclopramide in pure durg and pharmaceutical formulation.The common excipients and additives did not interfere in this method. A simple spectrophotometric method for the determination of metoclopramide in a pure form and in dosage forms pharmaceutical preparations has been developed. The proposed method is based on

Promethazine Oxidation by Redox Mediation in Peroxidase Reactions

The effect of promethazine on peroxidase-catalyzed oxidation of 3,3′,5,5′-tetramethylbenzidine was investigated at pH 5.4. Promethazine dose dependently introduced a lag in the appearance of tetramethylbenzidine charge-transfer complex monitored at 652 nm. Increasing concentrations of tetramethylbenzidine however decreased the lag period proportional to the tetramethylbenzidine concentration. Addition of promethazine to preformed charge transfer complex caused rapid bleaching of the blue-colored complex. Titration of promethazine with the yellow-colored diimine gave rise to the blue charge-transfer complex and the complete reduction of the species to the colorless parent amine compound. The available evidence suggests that promethazine is oxidized via redox mediation by tetramethylbenzidine peroxidase-oxidized products.

Kinetic fluorimetric determination of promethazine by a stopped-flow mixing technique

The oxidation of promethazine to its corresponding fluorescent sulphoxide was used to develop a novel kinetic fluorimetric method for the determination of this drug. The use of a stopped-flow mixing technique makes use of an oxidizing reagent unnecessary because the oxidation is rapidly carried out by dissolved oxygen. The method is simple and fast as it only requires a few seconds to obtain kinetic data which allows ready application to routine analyses. The calibration graph is linear over the range 0.5–80 μg ml −1 and the precision (%RSD) is close to 2%. The method was applied to the determination of promethazine hydrochloride in two pharmaceutical preparations.

Spectrophotometric determination of promethazine by flow injection analysis and oxidation by CeIV

A flow injection analysis (FIA) procedure is proposed for the determination of promethazine. The sample solution is directly injected into the carrier-reagent stream which comprises a solution of ceric ions in a sulphuric acid medium. The absorbance at 514 nm from the red colour developed by the oxidation of promethazine is measured. Effects of foreign substances have been investigated and the procedure has been applied to the determination of promethazine in a pharmaceutical formulation (tablets).

Applications in drug analysis of carbon paste electrodes modified by fatty acids

The oxidation of promethazine as a model compound has been studied by adsorptive stripping voltammetry at carbon paste electrodes (CPE). A modification of the carbon paste matrix with fatty acids allows greater preconcentration of the molecule at the electrode surface. Several fatty acids of different chain length have been tested. The modification of the CPE with lauric acid has been successfully applied in the quantiative analysis of promethazine in standard serum samples. The influence of several parameters affecting the accumulation step has been investigated such as: pH, ionic strength, interfering ions, paste composition. The detection limit in phosphate buffer at pH 9.0 ( t acc = 5 min) has been found to be 1 × 10 −10 M.

Determination of promethazine by anodic differential-pulse voltammetry

A differential-pulse voltammetric method is described for the determination of promethazine hydrochloride. The method is based on the anodic oxidation of promethazine on a glassy carbon electrode at + 0.64 V vs. SCE in Prideaux buffer of pH 2.3. The reversibility of the oxidation was tested by cyclic voltammetry; the electrode process is quasi-reversible. From the results of microcoulometric experiments and a study of acid—base equilibria, a mechanism for the electrochemical oxidation is presented. The method is applied to determine promethazine hydrochloride in pharmaceutical formulations. Calibrations are linear over the 0.1–1 and 1–5 mg/50 cm 3 ranges.

Oxidative Degradation of Pharmaceutically Important Phenothiazines III: Kinetics and Mechanism of Promethazine Oxidation

The kinetics of the thermal degradation of promethazine in an acidic medium under various conditions were investigated. The degradation of promethazine and the formation of some degradation products were studied under aerobic and anaerobic conditions. The influence of pH, metal ions such as copper(II) and iron(III), and antioxidants was investigated. In an oxygen-saturated medium, promethazine generally followed first-order kinetics. Increasing the pH increased the degradation rate to a limiting value at pH 5. Addition of copper(II) increased the degradation rate over the whole process, while iron(III) caused an increase for only a short time. Ascorbic acid sometimes increased the degradation rate, while higher concentrations of hydroquinone also accelerated the degradation. Pyrosulfite did not have any influence. Under anaerobic conditions, promethazine degraded only in the presence of copper(II) and iron(III) ions. As a result of the studies on the qualitative and quantitative aspects of the oxidation process, a mechanism for the oxidative degradation of promethazine is suggested. Promethazine 5-oxide and a number of degradation products without intact side chains are formed via a semiquinone free radical. The influence of several factors on the degradation process is discussed.

Kinetics and Mechanism of Oxidation of Promazine and Promethazine by Ferric Perchlorate

The equilibrium constants, kinetics, and mechanism of promazine and promethazine oxidation by ferric perchlorate were investigated at different temperatures and acidities using a stopped-flow spectrophotometric technique. The overall reaction can be represented as follows:FeIII+P⇄k−1k1FeII+P·+where P•+ represents the radical cation corresponding to the phenothiazine derivative. The equilibrium quotients were evaluated at 1.00 M HCIO4, 25.0°, and ionic strength 1.0 M. The kinetics of reaction follow the equation:−dPdt=k1Fe3+P−k−1Fe2+P·+The rate constants k1 and k−1 are independent of acidity and are related to the corresponding equilibrium quotients.