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Polymers Aug 2023The safety of a medicinal product is determined by its pharmacological and toxicological profile, which depends not only on the active substance's toxicological... (Review)
Review
The safety of a medicinal product is determined by its pharmacological and toxicological profile, which depends not only on the active substance's toxicological properties, but also on the impurities it contains. Because impurities are a problem that must be considered to ensure the safety of a drug product, many studies have been conducted regarding the separation or purification of active pharmaceutical ingredients (APIs) and the determination of impurities in APIs and drug products. Several studies have applied molecularly imprinted polymers (MIPs) to separate impurities in active ingredients and as adsorbents in the sample preparation process. This review presents the design of MIPs and the methods used to synthesise MIPs to separate impurities in APIs and drug product samples, the application of MIPs to separate impurities, and a view of future studies involving MIPs to remove impurities from pharmaceutical products. Based on a comparison of the bulk and surface-imprinting polymerisation methods, the MIPs produced by the surface-imprinting polymerisation method have a higher adsorption capacity and faster adsorption kinetics than the MIPs produced by the bulk polymerisation method. However, the application of MIPs in the analysis of APIs and drug products are currently only related to organic compounds. Considering the advantages of MIPs to separate impurities, MIPs for other impurities still need to be developed, including multi-template MIPs for simultaneous separation of multiple impurities.
PubMed: 37631457
DOI: 10.3390/polym15163401 -
The Science of the Total Environment Oct 2022A 620-day batch experiment was conducted to examine the generation of nano-sized plastic particles and migration of organic compounds derived from plastic additives and...
A 620-day batch experiment was conducted to examine the generation of nano-sized plastic particles and migration of organic compounds derived from plastic additives and impurities during the weathering of three common plastic types in water with and without reactive oxygen species. The results show that the amount of nanoplastics plus organic compounds liberated from the tested plastic films, as indicated by total organic carbon, was in the following decreasing order: PET >PP > ABS. Hydroxyl radical generated from Fenton-like reaction significantly enhanced the generation of nanoplastics and release of organic compounds from the weathered plastic films via oxidative degradation. Over 30 organic compounds including potentially toxic organic pollutants originated from plastic additives and impurities were detected. There was a marked difference in the plastic nanoparticle size distribution between the deionized water and the water containing reactive oxygen species. The strong oxidizing capacity of hydroxyl radical resulted in rapider disintegration of the coarser nanoparticles (>500 nm) into the finer nanoparticles (<500 nm) and allowed complete decomposition of the nanoplastics with a size <50 nm or even <100 nm. Elevated level of Ca was detected on the surfaces of the ABS and PP nanoparticles. PP- and PET-derived nanoplastics contained heavy metal(loid)s while no heavy metal(loid)s was detected for the ABS nanoparticles. PET nanoparticles had a stronger capacity to bind S- and N-containing organic ligands compared to the other two plastic nanoparticles. The nanoplastics generated from the weathering were irregular in shape, which means that they had larger specific area compared to spherical engineered nanoplastics.
Topics: Hydroxyl Radical; Microplastics; Nanoparticles; Organic Chemicals; Plastics; Reactive Oxygen Species; Water; Water Pollutants, Chemical
PubMed: 35750181
DOI: 10.1016/j.scitotenv.2022.156859 -
Journal of Hazardous Materials Mar 2016The widespread use and increasing inventory of brominated flame retardants (BFRs) have caused considerable concern, as a result of BFRs emissions to the environment and... (Review)
Review
The widespread use and increasing inventory of brominated flame retardants (BFRs) have caused considerable concern, as a result of BFRs emissions to the environment and of the formation of both polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and mixed polybromochloro-dibenzo-p-dioxins and dibenzofurans (PBCDD/Fs or PXDD/Fs). Structural similarities between PBDD/Fs and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) suggest the existence of comparable formation pathways of both PBDD/Fs and PCDD/Fs, yet BFRs also act as specific precursors to form additional PBDD/Fs. Moreover, elementary bromine (Br2) seems to facilitate chlorination by bromination of organics, followed by Br/Cl-exchange based on displacement through the more reactive halogen. Overall, PBDD/Fs form through three possible pathways: precursor formation, de novo formation, and dispersion of parts containing BFRs as impurities and surviving a fire or other events. The present review summarises the formation mechanisms of both brominated (PBDD/Fs) and mixed dioxins (PXDD/Fs with X=Br or Cl) from BFRs, recaps available emissions data of PBDD/Fs and mixed PXDD/Fs from controlled waste incineration, uncontrolled combustion sources and accidental fires, and identifies and analyses the effects of several local factors of influence, affecting the formation of PBDD/Fs and mixed PXDD/Fs during BFRs combustion.
PubMed: 26546701
DOI: 10.1016/j.jhazmat.2015.10.014 -
Water Science and Technology : a... Nov 2022Due to industrialization and population growth, freshwater supplies are diminishing and becoming impure with high organic pollutant concentrations such as nitrate and... (Review)
Review
Due to industrialization and population growth, freshwater supplies are diminishing and becoming impure with high organic pollutant concentrations such as nitrate and phosphate, which shows a high adverse impact on aquatic and human lives. In drinking water sources, particularly groundwater, nitrate is considered as one of the major pollutants which causes methemoglobinemia (in newborn infants), carcinogenic activities and diabetes. Excess concentration of phosphate leads to eutrophication and death of aquatic species due to reduced dissolved oxygen content. Therefore, all countries must implement highly effective technologies for treating wastewater. Chitosan and zeolite are naturally occurring and cost-effective adsorbent materials with a higher surface area that exhibit greater nitrate and phosphate adsorption. Surface modification of chitosan and zeolite increases the adsorption capacity of adsorbents for the removal of both anions selectively. This paper reviews the current development of modified chitosan and zeolite adsorbents for anion adsorption, with an emphasis on modification by zero and multivalent metals and metal oxides, different surfactants, biomass-derived carbon, and natural and synthetic polymers. Multiple adsorption parameters, optimum adsorption condition, adsorption mechanism, regeneration study, research gap and future aspects have been explained for further research work.
Topics: Infant; Infant, Newborn; Humans; Nitrates; Phosphates; Zeolites; Chitosan; Nitrogen Oxides; Environmental Pollutants
PubMed: 36450679
DOI: 10.2166/wst.2022.366 -
Waste Management (New York, N.Y.) Mar 2022Digestate is a nutrient-rich by-product from organic waste anaerobic digestion but can contribute to nutrient pollution without comprehensive management strategies. Some... (Review)
Review
Digestate is a nutrient-rich by-product from organic waste anaerobic digestion but can contribute to nutrient pollution without comprehensive management strategies. Some nutrient pollution impacts include harmful algal blooms, hypoxia, and eutrophication. This contribution explores current productive uses of digestate by analyzing its feedstocks, processing technologies, economics, product quality, impurities, incentive policies, and regulations. The analyzed studies found that feedstock, processing technology, and process operating conditions highly influence the digestate product characteristics. Also, incentive policies and regulations for managing organic waste by anaerobic digestion and producing digestate as a valuable product promote economic benefits. However, there are not many governmental and industry-led quality assurance certification systems for supporting commercializing digestate products. The sustainable and safe use of digestate in different applications needs further development of technologies and processes. Also, incentives for digestate use, quality regulation, and social awareness are essential to promote digestate product commercialization as part of the organic waste circular economy paradigm. Therefore, future studies about circular business models and standardized international regulations for digestate products are needed.
Topics: Anaerobiosis; Environment; Eutrophication
PubMed: 35032793
DOI: 10.1016/j.wasman.2021.12.035 -
Biomedical Chromatography : BMC Jun 2023The aim of this study is to develop a stability-indicating, reversed-phase HPLC method for the quantification of assay and organic impurities (process and degradation)...
The aim of this study is to develop a stability-indicating, reversed-phase HPLC method for the quantification of assay and organic impurities (process and degradation) of doxycycline hyclate in a doxycycline injectable formulation. Both the active and dosage forms are officially present in the USP monograph, and assay and impurity methods are provided by separate UPLC techniques, which are highly sensitive to the flow rate and temperature, considering the quality control requirements and user-friendliness. A simple stability-indicating HPLC method with a shorter run time was developed for the simultaneous quantification of assay and impurity. The method was developed using HPLC with a gradient program and a reversed-phase Waters XBridge BEH C8 column (150 × 4.6 mm, 3.5 μm i.d.). Mobile phase A consisted of phosphate buffer (pH 8.5, 25 mM potassium phosphate, 2 mM ethylenediaminetetraacetic acid, and 0.5 ml of triethylamine). Mobile phase B consisted of methanol with a flow rate of 1.7 ml/min, a column temperature of 55°C, a UV wavelength of 270 nm, and an injection volume of 25 μl. Modern research represents a concomitant method for quantifying assay and organic impurities of doxycycline hyclate (active form) and doxycycline for injection (dosage form). The assay and impurity method were validated per United States Pharmacopeia (USP) 1225 and International Conference on Harmonization (ICH) guidelines. The retention time of doxycycline and degradation impurity, 4-epidoxycycline, was about 9.8 and 6.4 min, respectively. The linearity range of doxycycline and 4-epidoxycycline was 0.5-150 and 0.5-18 μg/ml, respectively. The percentage of recovery of doxycycline and 4-epidoxycycline was 98.7-100.6% and 88.0-112.0%. Validation of the analytical method demonstrated that the method is suitable, specific, linear, accurate, precise, rugged, and stability indicating for estimating the assay, known and degraded impurities of doxycycline, and doxycycline for injection.
Topics: Chromatography, High Pressure Liquid; Drug Stability; Doxycycline; Quality Control
PubMed: 36930874
DOI: 10.1002/bmc.5626 -
Materials (Basel, Switzerland) Jun 2023Charge transport characteristics in organic semiconductor devices become altered in the presence of traps due to defects or impurities in the semiconductors. These traps...
Charge transport characteristics in organic semiconductor devices become altered in the presence of traps due to defects or impurities in the semiconductors. These traps can lead to a decrease in charge carrier mobility and an increase in recombination rates, thereby ultimately affecting the overall performance of the device. It is therefore important to understand and mitigate the impact of traps on organic semiconductor devices. In this contribution, the influence of the capture and release times of trap states, recombination rates, and the Lorentz force on the net charge of a low-mobility organic semiconductor was determined using the finite element method (FEM) and Hall effect method through numerical simulations. The findings suggest that increasing magnetic fields had a lesser impact on net charge at constant capture and release times of trap states. On the other hand, by increasing the capture time of trap states at a constant magnetic field and fixed release time, the net charge extracted from the semiconductor device increased with increasing capture time. Moreover, the net charge extracted from the semiconductor device was nearly four and eight times greater in the case of the non-Langevin recombination rates of 0.01 and 0.001, respectively, when compared to the Langevin rate. These results imply that the non-Langevin recombination rate can significantly enhance the performance of semiconductor devices, particularly in applications that require efficient charge extraction. These findings pave the way for the development of more efficient and cost-effective electronic devices with improved charge transport properties and higher power conversion efficiencies, thus further opening up new avenues for research and innovation in this area of modern semiconductor technology.
PubMed: 37445005
DOI: 10.3390/ma16134691 -
Biomedical Chromatography : BMC Apr 2022Montelukast sodium (MLS) is a leukotriene receptor antagonist drug used in the treatment of asthma, bronchospasm, allergic rhinitis and urticaria. A reversed-phase high...
Montelukast sodium (MLS) is a leukotriene receptor antagonist drug used in the treatment of asthma, bronchospasm, allergic rhinitis and urticaria. A reversed-phase high performance liquid chromatography method was developed to separate, identify and quantitative determination of MLS and its eight known organic impurities in tablet dosage form using a C column and mobile phases consisting of a gradient mixture of pH 2.5 phosphate buffer and acetonitrile. The stability-indicating character of the developed method was proven using stress testing (1 m HCl at 80°C/30 min, 1 m NaOH at 80°C/30 min, H O at 80°C/30 min, 3% H O at 25°C/1 min, dry heat at 105°C/10 h and UV-vis light/4 days) and was validated for specificity, quantitation limit, linearity, precision, accuracy and robustness. For MLS and its eight known impurities, the quantitation limits, linearity and recoveries were 0.015-0.03 μg/ml, correlation coefficient > 0.997 (R > 0.995) and 85.5-107.0%, respectively. The developed chromatographic method is suitable for impurity profiling and also for assay determination of MLS in bulk drugs and pharmaceutical formulations. The mass values (m/z) of newly formed degradation products (DP1 and DP2) of montelukast sodium were identified using liquid chromatography-mass spectrometry.
Topics: Acetates; Chromatography, High Pressure Liquid; Chromatography, Liquid; Cyclopropanes; Drug Stability; Quinolines; Reproducibility of Results; Sulfides; Tablets
PubMed: 34994006
DOI: 10.1002/bmc.5330 -
Journal of Environmental Sciences... Nov 2020Few studies have been carried out to connect nutrient recovery as struvite from wastewater and sustainable utilization of the recovered struvite for copper and zinc...
Few studies have been carried out to connect nutrient recovery as struvite from wastewater and sustainable utilization of the recovered struvite for copper and zinc immobilization in contaminated soil. This study revealed the effect of struvite on Cu and Zn immobilization in contaminated bio-retention soil in the presence of commonly exuded plant organic acids. The research hypothesis was that the presence of both struvite and organic acids may influence the immobilization of Cu and Zn in soil. The outcome of this research confirmed that more than 99% of Cu and Zn was immobilized in bio-retention filter media by struvite application. Water-soluble Cu and Zn concentrations of struvite treated soil were less than 1.83 and 0.86 mg/kg respectively, and these concentrations were significantly lower compared to the total Cu and Zn content of 747.05 mg/kg in the contaminated soil. Application of struvite to Cu- and Zn-contaminated soil resulted in formation of compounds similar to zinc phosphate tetrahydrate (Zn(PO)•4HO) and amorphous Cu and Zn phases. Struvite was effective in heavy metal remediation in acidic soil regardless of the presence of Ca impurities in struvite and the presence of plant organic acids in soil. Overall, this study revealed that struvite recovered from wastewater treatment plants has potential for use as an amendment for heavy metal remediation in contaminated bio-retention soil.
Topics: Copper; Metals, Heavy; Soil; Soil Pollutants; Struvite; Zinc
PubMed: 32933738
DOI: 10.1016/j.jes.2020.04.023 -
Journal of the American Chemical Society Apr 2023Organic hierarchical branch micro/nanostructures constituted by single crystals with inherent multichannel characteristics exhibit superior potential in regulating...
Organic hierarchical branch micro/nanostructures constituted by single crystals with inherent multichannel characteristics exhibit superior potential in regulating photon transmission for photonic circuits. However, organic branch micro/nanostructures with precise branch positions are extremely difficult to achieve due to the randomness of the nucleation process. Herein, by taking advantage of the dislocation stress field-impurity interaction that solute molecules deposit preferentially along the dislocation line, twinning deformation was introduced into microcrystals to induce oriented nucleation sites, and ultimately organic branch microstructures with controllable branch sites were fabricated. The growth mechanism of these controllable single crystals with an angle of 140° between trunk and branch is attributed to the low lattice mismatching ratio (η) of 4.8%. These as-prepared hierarchical branch single crystals with asymmetrical optical waveguide characteristics have been demonstrated as an optical logic gate with multiple input/out channels, which provides a route to command the nucleation sites and offers potential applications in the organic optoelectronics at the micro/nanoscale.
PubMed: 37040147
DOI: 10.1021/jacs.3c02061