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PDA Journal of Pharmaceutical Science... 2020Urea is used in biopharmaceutical manufacturing processes for the purification of therapeutic proteins, for cleaning columns, and for refolding proteins after...
Urea is used in biopharmaceutical manufacturing processes for the purification of therapeutic proteins, for cleaning columns, and for refolding proteins after purification. The urea used for such purposes is typically USP grade material obtained from commercial sources and further characterization is required prior to use, such as determination of purity and identity. For this purpose, a robust analytical method is needed that can characterize the known organic impurities of urea. However, the existing methods show high assay variability and are not able to resolve all known organic impurities as desired for accurate quantification. In the present manuscript we developed a new high-performance liquid chromatography method with UV detection for the separation of urea and its impurities (biuret, cyanuric acid, and triuret). The method performance characteristics evaluated for urea and biuret were specificity, linearity, accuracy, identity, precision, and robustness and the newly developed method met all predefined performance acceptance criteria.
Topics: Chromatography, High Pressure Liquid; Drug Contamination; Reproducibility of Results; Ultraviolet Rays; Urea
PubMed: 31209168
DOI: 10.5731/pdajpst.2018.009803 -
International Journal of Molecular... Nov 2018Graphene, graphene oxide, and reduced graphene oxide have been widely considered as promising candidates for industrial and biomedical applications due to their... (Review)
Review
Graphene, graphene oxide, and reduced graphene oxide have been widely considered as promising candidates for industrial and biomedical applications due to their exceptionally high mechanical stiffness and strength, excellent electrical conductivity, high optical transparency, and good biocompatibility. In this article, we reviewed several techniques that are available for the synthesis of graphene-based nanomaterials, and discussed the biocompatibility and toxicity of such nanomaterials upon exposure to mammalian cells under in vitro and in vivo conditions. Various synthesis strategies have been developed for their fabrication, generating graphene nanomaterials with different chemical and physical properties. As such, their interactions with cells and organs are altered accordingly. Conflicting results relating biocompatibility and cytotoxicity induced by graphene nanomaterials have been reported in the literature. In particular, graphene nanomaterials that are used for in vitro cell culture and in vivo animal models may contain toxic chemical residuals, thereby interfering graphene-cell interactions and complicating interpretation of experimental results. Synthesized techniques, such as liquid phase exfoliation and wet chemical oxidation, often required toxic organic solvents, surfactants, strong acids, and oxidants for exfoliating graphite flakes. Those organic molecules and inorganic impurities that are retained in final graphene products can interact with biological cells and tissues, inducing toxicity or causing cell death eventually. The residual contaminants can cause a higher risk of graphene-induced toxicity in biological cells. This adverse effect may be partly responsible for the discrepancies between various studies in the literature.
Topics: Animals; Biocompatible Materials; Cell Death; Cell Survival; Graphite; Humans; Nanostructures; Polymers
PubMed: 30424535
DOI: 10.3390/ijms19113564 -
PloS One 2021Industrial waste salt is classified as hazardous waste to the environment. The organic impurity and its occurrence in industrial waste salt affect the salt resource...
Industrial waste salt is classified as hazardous waste to the environment. The organic impurity and its occurrence in industrial waste salt affect the salt resource utilization. In this paper, composition quantitative analysis, XRD, TG-DSC, SEM/FIB-SEM coupled with EDS, FTIR, XPS and GC-Ms were chosen to investigate the organic impurity and its occurrence in industrial waste salt. The organic impurities owe small proportion (1.77%) in the specimen and exhibit weak thermal stability within the temperature of 600°C. A clear definition of organic impurity, including 11 kinds of organic compounds, including aldehyde, benzene and its derivatives etc., were detected in the industrial waste salt. These organic impurities, owing (C-O/C-O-C, C-OH/C = O, C-C/CHx/C = C etc.)-containing function group substance, are mainly distributed both on the surface and inside of the salt particles. Meanwhile, the organic substance may combine with metal cations (Ni2+, Mg2+, Cu2+ etc.) through functional groups, such as hydroxide, carbonyl etc., which increases its stability in the industrial waste salt. These findings provide comprehensive information for the resource utilization of industrial waste salt from chemical industry etc.
Topics: Chemical Phenomena; China; Hazardous Waste; Industrial Waste; Organic Chemicals; Salts; Sodium Chloride
PubMed: 34415952
DOI: 10.1371/journal.pone.0256101 -
Drug Testing and Analysis Mar 2022The National Measurement Institute's Methylamphetamine Profiling Program has evolved over the last 15 years to address analytical challenges faced with changes in... (Review)
Review
The National Measurement Institute's Methylamphetamine Profiling Program has evolved over the last 15 years to address analytical challenges faced with changes in illicit methylamphetamine production. The program involves organic and inorganic analysis of methylamphetamine to determine the precursors and synthetic route used in manufacture. This paper discusses changes in the methylamphetamine chemical profile for samples received at this laboratory during January 2011 to December 2020. In particular, changes observed in the methylamphetamine purity, potency, synthetic route, precursor and precursor synthetic origin are discussed. Over 13,180 samples were analysed during this period consisting of samples seized on the streets and the Australian border. This paper shows correlations between methylamphetamine seizures at the Australian border with international clandestine laboratory and precursor seizures trends. As the illicit drug landscape changes so too must our approach to chemical profiling if we are to confidently determine the synthetic origin of methylamphetamine.
Topics: Australia; Commerce; Illicit Drugs; Methamphetamine
PubMed: 34156767
DOI: 10.1002/dta.3117 -
The Journal of Physical Chemistry... Apr 2023Organic semiconductors have found a broad range of application in areas such as light emission, photovoltaics, and optoelectronics. The active components in such devices... (Review)
Review
Organic semiconductors have found a broad range of application in areas such as light emission, photovoltaics, and optoelectronics. The active components in such devices are based on molecular and polymeric organic semiconductors, where the density of states is generally determined by the disordered nature of the molecular solid rather than energy bands. Inevitably, there exist states within the energy gap which may include tail states, deep traps caused by unavoidable impurities and defects, as well as intermolecular states due to (radiative) charge transfer states. In this Perspective, we first summarize methods to determine the absorption features due to the subgap states. We then explain how subgap states can be parametrized based upon the subgap spectral line shapes. We finally describe the role of subgap states in the performance metrics of organic semiconductor devices from a thermodynamic viewpoint.
PubMed: 36961944
DOI: 10.1021/acs.jpclett.3c00021 -
Environmental Science and Pollution... Jan 2022Water is one of the basic necessities of life and having clean water is extremely important for human health. In recent years, β-cyclodextrin (β-CD)-based polymers and... (Review)
Review
Water is one of the basic necessities of life and having clean water is extremely important for human health. In recent years, β-cyclodextrin (β-CD)-based polymers and nanosystems have been extensively studied as adsorbents for the purpose of water purification. They present high efficiency and capability to remove inorganic, organic, and heavy metal impurities from wastewater as compared to conventional methods of water purification. β-CDs are cyclic polysaccharides having specific dimension of hydrophobic cavities and hydrophilic functional groups. The hydrophobic cavities form inclusion complexes through host-guest interactions. The hydroxyl groups form sites of hydrogen bonding and electrostatic interaction with pollutants. Additionally, they are also the sites of modification to bring about different derivatisation and polymerization reactions in order to impart desirable properties for efficient adsorption material. This article comprises of various derivatives of β-cyclodextrins: their nanoparticulate systems and their characterization and applications to remove different types of impurities from wastewater. The chemical reactions for their synthesis and mechanism of adsorption are highlighted.
Topics: Cyclodextrins; Humans; Water Pollutants, Chemical; Water Purification; beta-Cyclodextrins
PubMed: 34686957
DOI: 10.1007/s11356-021-17014-3 -
Journal of Environmental Management Oct 2022High-silica phosphogypsum (PG) is a kind of industrial by-product with great utilization potential. However, it is difficult to reuse PG directly due to the related...
High-silica phosphogypsum (PG) is a kind of industrial by-product with great utilization potential. However, it is difficult to reuse PG directly due to the related gangue minerals (e.g., SiO), and thus efficient purification is required to allow its further applications. Herein, a typical high-silica phosphogypsum waste was purified by a new "reverse-direct flotation" method. The organic matters and fine slimes were removed by reverse flotation, and then, the silica impurity was removed by direct flotation. Via the closed-circuit flotation process, the whiteness of the PG concentrate is improved from 33.23 to 63.42, and the purity of gypsum in the PG concentrate increases from 83.90% to 96.70%, with a gypsum recovery of 85%. Additionally, the content of SiO is significantly reduced from 11.11% to 0.07%. In-depth investigations suggest that the difference in the floatability of gypsum and quartz is prominently intensified by flotation reagents at pH = 2-2.5, and thus leads to good desilication performance. Further characteristics of the PG concentrate prove that impurities have been well removed, and the PG concentrate meets the requirement of related standards for gypsum building materials. The flotation method reported here paves the way for the purification of high-silica phosphogypsum, which can be extended to the purification and value-added reutilization of other industrial solid wastes.
Topics: Calcium Sulfate; Industrial Waste; Phosphorus; Silicon Dioxide
PubMed: 35932745
DOI: 10.1016/j.jenvman.2022.115824 -
Journal of Pharmaceutical and... Dec 2014Peptides are an increasingly important group of pharmaceuticals, positioned between classic small organic molecules and larger bio-molecules such as proteins. Currently,... (Review)
Review
Peptides are an increasingly important group of pharmaceuticals, positioned between classic small organic molecules and larger bio-molecules such as proteins. Currently, the peptide drug market is growing twice as fast as other drug markets, illustrating the increasing clinical as well as economical impact of this medicine group. Most peptides today are manufactured by solid-phase peptide synthesis (SPPS). This review will provide a structured overview of the most commonly observed peptide-related impurities in peptide medicines, encompassing the active pharmaceutical ingredients (API or drug substance) as well as the finished drug products. Not only is control of these peptide-related impurities and degradants critical for the already approved and clinically used peptide-drugs, these impurities also possess the capability of greatly influencing initial functionality studies during early drug discovery phases, possibly resulting in erroneous conclusions. The first group of peptide-related impurities is SPPS-related: deletion and insertion of amino acids are related to inefficient Fmoc-deprotection and excess use of amino acid reagents, respectively. Fmoc-deprotection can cause racemization of amino acid residues and thus diastereomeric impurities. Inefficient deprotection of amino acid side chains results into peptide-protection adducts. Furthermore, unprotected side chains can react with a variety of reagents used in the synthesis. Oxidation of amino acid side chains and dimeric-to-oligomeric impurities were also observed. Unwanted peptide counter ions such as trifluoroacetate, originating from the SPPS itself or from additional purification treatments, may also be present in the final peptide product. Contamination of the desired peptide product by other unrelated peptides was also seen, pointing out the lack of appropriate GMP. The second impurity group results from typical peptide degradation mechanisms such as β-elimination, diketopiperazine, pyroglutamate and succinimide formation. These SPPS- and degradation-related impurity types can also found in the finished peptide drug products, which can additionally contain a third group of related impurities, i.e. the API-excipient degradation products.
Topics: Drug Contamination; Drug Discovery; Humans; Peptides
PubMed: 25044089
DOI: 10.1016/j.jpba.2014.06.012 -
Chemosphere Nov 2022Amplified anthropogenic release of volatile organic compounds (VOCs) gets worse air quality and human health. Photocatalytic degradation of VOCs is the practical... (Review)
Review
Amplified anthropogenic release of volatile organic compounds (VOCs) gets worse air quality and human health. Photocatalytic degradation of VOCs is the practical strategy due to its low cost, simplicity, high efficiency, and environmental sustainability. Different types of photocatalyst activated by UV and visible lights are applied for VOC degradation. This review tries to investigate the state-of-art of recently published papers on this subject with a focus on the high-efficiency photocatalyst. The novel photocatalysts are introduced and enhancing photocatalytic activity strategies such as the hybrid of two/three photocatalyst, impurity doping, and heterojunctions with narrow bandgap semiconductors have been explained. The procedures of visible light activation of the photocatalysts are discussed with attention to current problems and future challenges. In addition, effective operational parameters in the photocatalytic degradation of VOCs have been reviewed with their advantages and drawbacks. A series of strategies are developed for the efficient utilization of visible light photocatalysts and improving new materials or design structures to degrade produced toxic intermediates/by-products during photocatalytic degradation of VOCs. This review shows that there are significant challenges in the applications of photocatalysts in the selective removal of VOCs. Several approaches should be combined to produce synergistic effects, which may lead to much higher photocatalytic performance than individual strategies. Another challenge is to develop efficient photocatalysts to meet real problems on an industrial scale.
Topics: Catalysis; Humans; Light; Semiconductors; Volatile Organic Compounds
PubMed: 35817187
DOI: 10.1016/j.chemosphere.2022.135655 -
Journal of Pharmaceutical and... Jan 2023One of the impurities of acetaminophen, N,N'-(oxydi-4,1-phenylene)diacetamide (ODAA), which is not specified in the organic impurities analysis method of acetaminophen...
One of the impurities of acetaminophen, N,N'-(oxydi-4,1-phenylene)diacetamide (ODAA), which is not specified in the organic impurities analysis method of acetaminophen by high performance liquid chromatography (HPLC) in American Pharmacopoeia Version 42 (USP 42), was synthesized, characterized and standardized. A new and optimized liquid chromatographic method for the determination of organic impurities of acetaminophen was developed using an ultra-high performance liquid chromatographic (UHPLC) system, which can separate this impurity. This new liquid chromatographic method has been optimized and validated for the simultaneous determination of acetaminophen related compound B, acetaminophen related compound C, acetaminophen related compound D, acetaminophen related compound J and ODAA, the organic impurities in acetaminophen drug substance. Acetaminophen was also subjected to stress-testing under acidic hydrolysis, alkaline hydrolysis, oxidative degradation, thermal degradation and photolytic degradation for 15 days. The impurity molecule, ODAA was synthesized using 4,4'-oxydianiline and acetic anhydride. The chemical structure of the synthesized ODAA molecule was confirmed by characterization studies. The potency of ODAA was found to be 99.64% as a result of the relevant analyses. The chromatographic separation was achieved on a C8 (150 mm × 2.1 mm; 2-µm particle size) reversed-phase column using a gradient elution, being solvent A: methanol-water-glacial acetic acid (50:950:1, v/v/v) and solvent B: methanol-water-glacial acetic acid (500:500:1, v/v/v) flowing at a rate of 0.2 mL/min. The limits of quantitation (S/N 10:1) were 1.248 µg/mL for acetaminophen, 0.373 µg/mL for acetaminophen related compound B, 1.217 µg/mL for acetaminophen related compound C, 0.369 µg/mL for acetaminophen related compound D, 0.125 µg/mL for acetaminophen related compound J and 0.373 µg/mL for ODAA. The individual mean recoveries of each impurity molecule spiked into acetaminophen samples at different concentration levels ranged from 93% to 104%. The method developed for UHPLC instrument was successfully applied to the analyses of different lots of acetaminophen. Thus, the proposed method can be used for determination of this impurity in the presence of other specified impurities of acetaminophen.
Topics: Acetaminophen; Drug Contamination; Methanol; Acetic Acid; Chromatography, High Pressure Liquid; Reference Standards; Solvents; Water; Reproducibility of Results
PubMed: 36327580
DOI: 10.1016/j.jpba.2022.115123