Presence Of P-aminophenol Research Articles

Effect of Genetic Algorithm-Based Wavelength Selection as a Preprocessing Tool on Multivariate Simultaneous Determination of Paracetamol, Orphenadrine Citrate, and Caffeine in the Presence of p-Aminophenol Impurity.

The utilization of selection methods such as genetic algorithm (GA) aims to construct better partial least squares (PLS) and principal component regression (PCR) models than those established from the full-spectrum range. Determination of paracetamol (PAR), orphenadrine citrate (Or.cit), and caffeine (CAF) in the presence of PAR nephrotoxic impurity [p-aminophenol (PAP)]. GA was applied to select the optimum wavelengths used. A calibration set was prepared in which the three drugs, together with PAP, were modeled by multilevel multifactor design. This calibration set was used to build the PLS and PCR models, either with or without preprocessing the data using GA. Results were compared with and without preprocessing, and this revealed that GA can find an optimized combination of spectral wavelengths, yielding a lower root mean square error of prediction as well as a lower number of latent variables used. The results of the two models show that simultaneous determination of the aforementioned drugs can be performed in the concentration ranges of 20-60, 3-11, and 1-9 μg/mL for PAR, Or.cit, and CAF, respectively. The proposed models were applied for the determination of the three drugs in their pharmaceutical formulations, and the results were verified by the standard addition technique. GA can be useful as a wavelength selection tool before applying multivariate PLS and PCR methods. GA gives an improvement in the predictive ability of the models with lower RMSEP and less number of latent variables (LVs). The proposed PLS, PCR, GA-PLS, and GA-PCR spectrophotometric methods were able to determine paracetamol, orphenadrine citrate, and caffeine in the presence of p-aminophenol and severe spectral overlapping.

Assessment of p-aminophenol oxidation by simulating the process of hair dyeing and occurrence in hair salon wastewater and drinking water from treatment plant

This work reports the study of oxidation reaction of p-aminophenol (PAP) in ammoniacal medium in dissolved atmospheric oxygen and hydrogen peroxide, simulating the process of hair dyeing with permanent dyes. The products formed, which included semi-quinoneimine radical, quinoneimine, dimers, trimers and tetramers, were identified by mass spectrometry, infrared spectroscopy, UV–vis spectrophotometry, and nuclear magnetic resonance of hydrogen. The process was found to involve an autoxidation mechanism. The mutagenicity of the products was carried out by Salmonella Typhimurium YG1041 assay, and the results indicated no mutagenic properties. The presence of PAP and its oxidative products in samples of wastewater collected from hairdressing salon effluent (WW), raw river water (RRW), and water inlet and outlet of drinking water treatment plant (DWTP) was analyzed by HPLC-DAD. PAP was detected in the collected samples of WW, water samples from DWTP (before and after treatment), at concentrations of 2.1 ± 0.5 mg L−1, 1.9 ± 0.3 × 10-3 mg L−1 and 1.3 ± 0.2 × 10-3 mg L−1, respectively. The reaction products, including dimers, trimers and tetramers were identified only in the WW sample; this shows that both the precursor in the sample and its derivatives were released into the wastewater.

Development and Validation of Chromatographic Methods for Simultaneous Determination of Paracetamol, Orphenadrine Citrate and Caffeine in Presence of P-aminophenol; Quantification of P-aminophenol Nephrotoxic Impurity Using LC-MS/MS.

Three chromatographic methods were developed, optimized and validated for Paracetamol (PAR), Orphenadrine citrate (Or.cit) and Caffeine (CAF) determination in their mixture and in presence of PAR toxic impurity; P-aminophenol (PAP) in tablets. The first method is based on a thin layer chromatography combined with densitometry. Separation was achieved using silica gel 60F254 TLC plates and dichloromethane:methanol:acetone:glacial acetic acid (9:1:0.5:0.3, v/v/v) as a developing system at 230nm. The second method is based on high-performance liquid chromatography with diode array detection. The proposed compounds are separated on a reversed phase C18 analytical column using phosphate buffer (pH9; 0.05M) and methanol (80:20, v/v) at 1.2mL/min. Linear regressions are obtained in the range of 1-500μg/mL, 25-1000μg/mL and 1-400μg/mL for PAR, Or.cit and CAF, respectively. Quantification of the toxic PAP is carried out using LC-MS-MS by electrospray ionization in the positive mode using triple quadrupole mass spectrometry. The limit of quantification for PAP is 1ng/mL. All methods are validated according to the ICH guidelines and successfully applied to determine PAR, Or.cit, CAF and PAP in pure powder and in combined tablets dosage form without interference from excipients.

The effect of aminophenol isomers on the reduced graphene oxide hydrogels’ microstructure and capacitive performances

To enhance the reduced graphene oxide hydrogels' capacitive performance, many modifiers are used to add doped element into the materials and improve the structure. The isomers of aminophenol which contain amino and hydroxyl groups on the benzene ring are employed as structure regulator and modifier to synthesize high-performance reduced graphene oxide hydrogels. The influences of preparation conditions including ratios of graphene oxide to aminophenol isomers, temperature, reaction times on the samples’ structure and properties have been investigated. The results show that the oligomer of o-aminophenol is formed on reduced graphene oxide sheets while the molecules of p, m-aminophenol are bound to the sheets; and that the hydrogel prepared in the presence of p-aminophenol has larger specific surface area, total pore volume, specific capacitance and good rate capability (74.0% of 427.0 F g−1 retains at 100 mV s−1) than other. The cells assembled by the optimized hydrogels exhibit the energy density of 14.07 Wh kg−1 at power density of 124.3 W kg−1, and 4.96 Wh kg−1 at 6.78 kW kg−1. Furthermore, 92.2% of initial capacitance can be retained after 20,000 cycles for the cells assembled by the optimal hydrogel. This kind of material may be found its use in energy storage field.

Visual and colorimetric detection of p-aminophenol in environmental water and human urine samples based on anisotropic growth of Ag nanoshells on Au nanorods

A simple, sensitive, selective and high-resolution colorimetric method has been developed for the detection of p-aminophenol in environmental water and human urine samples. In the presence of p-aminophenol, silver ions are reduced to silver atoms and subsequently Ag nanoshells anisotropically grow on the surface of Au nanorods to generate orange slice-like Au@Ag core–shell nanocrystals, thereby resulting in the blue-shift of longitudinal surface plasmon resonance band of Au nanorods accompanying a sharp-contrast multicolor change. Using Au@Ag core–shell nanocrystals as the transducer, sub-micromolar p-aminophenol can be detected by the colorimetric method and 10μmolL−1 p-aminophenol can be visual readout by the naked eyes. Furthermore, a simple, cheap, portable test kit is constructed for the visual assay of urinary p-aminophenol without complicated sample pretreatment and sophisticated instruments. The proposed colorimetric method has the potential for the rapid and on-site analyses of p-aminophenol in environmental water and human urine samples.

Chemometrics resolution and quantification power evaluation: Application on pharmaceutical quaternary mixture of Paracetamol, Guaifenesin, Phenylephrine and p-aminophenol

Three advanced chemmometric-assisted spectrophotometric methods namely; Concentration Residuals Augmented Classical Least Squares (CRACLS), Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) and Principal Component Analysis-Artificial Neural Networks (PCA-ANN) were developed, validated and benchmarked to PLS calibration; to resolve the severely overlapped spectra and simultaneously determine; Paracetamol (PAR), Guaifenesin (GUA) and Phenylephrine (PHE) in their ternary mixture and in presence of p-aminophenol (AP) the main degradation product and synthesis impurity of Paracetamol. The analytical performance of the proposed methods was described by percentage recoveries, root mean square error of calibration and standard error of prediction. The four multivariate calibration methods could be directly used without any preliminary separation step and successfully applied for pharmaceutical formulation analysis, showing no excipients’ interference.

HPTLC and RP-HPLC methods for simultaneous determination of Paracetamol and Pamabrom in presence of their potential impurities

Two chromatgraphic methods were developed for determination of Paracetamol (PCM) and Pamabrom (PAM) in presence of P-aminophenol (PAP) and Theophylline (THEO) as potential impurities of both drugs respectively. First method is HPTLC which depends on separation and quantitation of the studied drugs on aluminum plates pre-coated with silica gel 60 F254 as a stationary phase using chloroform:methanol:ethyl acetate:glacial acetic acid (8:0.8:0.6:0.2, v/v/v/v) as mobile phase followed by densitometric measurement of the bands at 254nm. Second method is RP-HPLC which comprises separation of the studied drugs on a Phenomenex C8 column by gradient elution using mobile phase consisting of sodium dihydrogen phosphate buffer (0.05M): methanol:acetonitrile (85:10:5, v/v/v) at a flow rate of 1mL/min for first 7.5min and (70:20:10, v/v/v) at a flow rate of 1.5mL/min for the next 5min. The proposed methods were successfully applied for determination of the potential impurities of PCM and PAM after resolving them from the pure drugs. The developed methods have been validated and proved to meet the requirements delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. The validated methods were successfully applied for determination of the studied drugs in their pharmaceutical formulation. The results were statistically compared to those obtained by the reported RP-HPLC method where no significant difference was found; indicating the ability of proposed methods to be used for routine quality control analysis of these drugs.

Simultaneous determination of paracetamol and diphenhydramine hydrochloride mixture in the presence of their degradation products

New accurate, selective, sensitive and precise methods were developed and validated for determination of paracetamol and diphenhydramine hydrochloride in the presence of P-amino phenol, the hydrolytic degradate and the most potential impurity of paracetamol and the N oxide degradation product of diphenhydramine in bulk form and in pharmaceutical formulation.Method A uses double divisor second derivative of ratio spectrophotometric technique, at 304nm for paracetamol and 256.4nm for diphenhydramine hydrochloride. Method B utilizes Principle Component Regression (PCR) and Partial Least Squares (PLS) chemometric techniques for quantification of the four components using a UV spectrum range of 210-350 nm. The proposed methods were successfully applied to the analysis of the mentioned drugs either in bulk powder or in pharmaceutical formulation without interference from other dosage form additives, and the results were statistically compared with the pharmacopoeial method.

Simultaneous Determination of Paracetamol and Diphenhydramine Hydrochloride in Presence of Paracetamol Degradation Product

Three sensitive , selective and precise stability indicating methods for simultaneous determination of Paracetamol and Diphenhydramine hydrochloride in their binary mixture and in presence of P-aminophenol; the potential impurity and degradation product of Paracetamol; were developed. In Method A, Paracetamol was determined in presence of Diphenhydramine Hydrochloride and P-aminophenol using the first derivative (1D) spectrophotometric method by measuring the peak amplitude at 264.5 nm where linear relationship was obtained in the range of 2-12 ?g mL-1 while Diphenhydramine Hydrochloride was determined in presence of Paracetamol and P-aminophenol using the first derivative of ratio spectra (1DD) method at 224 nm. Method B utilized chemometric techniques [Principal Component Regression (PCR) and Partial Least Squares(PLS)] which successfully applied to quantify both drugs and degradation product using the information included in the absorption spectra of appropriate solutions of the three compounds in the range of 220-340nm. Method C used HPTLC-densitometric method in which the aforementioned components were separated on silica gel plates using chloroform-ethyl acetate-ammonia solution (4:6:0.2, by volume) as a developing system. This was followed by quantitative densitometric measurement at 220 nm .Linear relationship were obtained in the concentration ranges of 0.4-1.6 ?g/band , 3-12 ?g /band and 0.4-1.6 ?g/band for Paracetamol, Diphenhydramine Hydrochloride and P-aminophenol respectively. The proposed methods have been successfully applied to the analysis of Paracetamol and Diphenhydramine Hydrochloride in their pharmaceutical formulation without interference from other dosage form additives and the results were statistically compared with official method.

Thermal behavior of a pharmaceutical solid acetaminophen doped with p-aminophenol.

Thermal behavior of a series of acetaminophen (APAP) doped with p-aminophenol (PANP) was studied by differential scanning calorimetry (DSC) to determine whether it exhibited a eutectic system. Within the temperature range of 120 to 200 degrees C, accurately weighed (1-2 mg) samples sealed in hermetic pans were calorimetrically scanned with a low scanning rate of 1 degrees C/min. The mixture formed a single eutectic with the composition ratio APAP/PANP of 0.6/0.4 at a temperature of 138 degrees C, where it liquefied. Melting began as early as at the eutectic point, which was below the melting temperature of APAP (169 degrees C). The melting point as well as heat of APAP fusion was depressed with the increase in doped PANP. It was postulated that there might be a deficit heat of APAP fusion in APAP doped with PANP, which was coincident with the heat consumed by early liquefaction. The deficit heat was used to correct fraction molten in the van't Hoff law of purity determination. It was found that the purity determination of APAP doped with PANP was comparable to the UV-spectroscopic method up to the maximum doped PANP level of 8 mol percent. It was concluded that DSC was able to approach early heat of liquefaction of APAP doped with PANP. The van't Hoff law may be applicable to the determination of APAP with the presence of PANP as a eutectic impurity.

The Fate of Aniline after a Photo-Fenton Reaction in an Aqueous System Containing Iron(III), Humic Acid, and Hydrogen Peroxide

The degradation of aniline (ArNH2) was facilitated by light irradiation (λ > 370 nm) of an aqueous solution, which contained Fe(III), humic acid (HA), and H2O2. The consumption of H2O2 and the reduction of Fe(III) to Fe(II) was consistent with the degradation of ArNH2 via the photo-Fenton reaction, accompanied by the generation of hydroxyl radicals (HO•). HPLC analysis of the reaction mixture indicated the presence of p-aminophenol, p-hydroquinone, and maleic and fumaric acids and the simultaneous release of NH4+ ion. However, the sum of the product concentrations, as determined by HPLC after the reaction, was much smaller than the ArNH2 concentration added initially. This can be attributed to the majority of the ArNH2 being incorporated into the polymeric structure in the HA after the reaction. The 15N NMR and pyrolysis-GC/MS studies indicated that, after the reaction, ArNH2 formed covalent bonds with quinone and the vinyl carbons in the HA, to form anilino-compounds, such as anilinoquinone and enaminone.

Toxicity of p-aminophenol and p-nitrophenol to Chlorella vulgaris and two species of Nostoc isolated from soil

An examination was made of the effects of p-aminophenol (PAP) treatment individually and in combination with its parent compound, p-nitrophenol (PNP), on growth and metabolic activities of a microalga, Chlorella vulgaris, and two cyanobacteria, Nostoc linckia and Nostoc muscorum, all isolated from soil. Comparatively, the cyanobacteria were more sensitive to the phenol treatments. All but the lowest (2 μg ml −1) PAP treatments inhibited cell number, chlorophyll a, and total carbohydrate production, 14CO 2 uptake, and nitrate reductase and nitrogenase activity. The algistatic effect in C. vulgaris caused by PAP could not be reverted even in the presence of acetate (0.1%). However, the inherent toxic effect of PNP established toward the alga and cyanobacteria was found alleviated in the presence of PAP only at lower concentrations. Transmission electron microscopy revealed many cytological abnormalities in Chlorella vulgaris under the influence of the selected phenols, indicating that the toxicants directly interfere with membrane properties and enzymes.

Flow-injection procedures for determination of iodide and iodate/iodide with spectrofluorimetric and spectrophotometric detection, respectively

Iodide was determined using a flow-injection system based on the catalytic reduction of cerium(IV) to fluorescent cerium(III) [λ(ex) = 260 nm, λ(em) = 350 nm]. Iodate and iodide were determined spectrophotometrically by a sensitive colour reaction with p-aminophenol. Iodide was oxidized by hydrogen peroxide to iodate in the presence of p-aminophenol. Iodate in turn oxidized p-aminophenol to an indamine dye which has an absorbance maximum at 540 nm.