scholarly journals Photo-Oxidation of Therapeutic Protein Formulations: From Radical Formation to Analytical Techniques

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 72
Author(s):  
Elena Hipper ◽  
Michaela Blech ◽  
Dariush Hinderberger ◽  
Patrick Garidel ◽  
Wolfgang Kaiser
Keyword(s):  
Light Exposure ◽  
Analytical Techniques ◽  
Oxidation Products ◽  
Oxygen Species ◽  
Ambient Light ◽  
Photo Degradation ◽  
Photo Oxidation ◽  
Protein Formulations ◽  
And Storage ◽  
Ensure Product Quality

UV and ambient light-induced modifications and related degradation of therapeutic proteins are observed during manufacturing and storage. Therefore, to ensure product quality, protein formulations need to be analyzed with respect to photo-degradation processes and eventually protected from light exposure. This task usually demands the application and combination of various analytical methods. This review addresses analytical aspects of investigating photo-oxidation products and related mediators such as reactive oxygen species generated via UV and ambient light with well-established and novel techniques.

TiO2 suspension exposed to H2O2 in ambient light or darkness: Degradation of methylene blue and EPR evidence for radical oxygen species

2013 ◽  
Vol 142-143 ◽  
pp. 662-667 ◽  
Author(s):  
Luis Domínguez Sánchez ◽  
Sébastien Francis Michel Taxt-Lamolle ◽  
Eli Olaug Hole ◽  
André Krivokapić ◽  
Einar Sagstuen ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Oxygen Species ◽  
Ambient Light ◽  
Radical Oxygen Species

scholarly journals Deliquescence, efflorescence, and phase miscibility of mixed particles of ammonium sulfate and isoprene-derived secondary organic material

2012 ◽  
Vol 12 (4) ◽  
pp. 9903-9943 ◽  
Author(s):  
M. L. Smith ◽  
A. K. Bertram ◽  
S. T. Martin
Keyword(s):  
Liquid Phase ◽  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Organic Material ◽  
Important Variable ◽  
Oxidation Products ◽  
Liquid Separation ◽  
Inorganic Particles ◽  
Photo Oxidation ◽  
Hygroscopic Properties

Abstract. The hygroscopic phase transitions of ammonium sulfate mixed with isoprene-derived secondary organic material were investigated in aerosol experiments. The organic material was produced by isoprene photo-oxidation at 40% relative humidity. The low volatility fraction of the photo-oxidation products condensed onto ammonium sulfate particles. The particle-phase organic material had oxygen-to-carbon ratios of 0.67 to 0.74 for mass concentrations of 20 to 30 μg m−3. The deliquescence, efflorescence, and phase miscibility of the mixed particles were investigated using a dual arm tandem differential mobility analyzer. The isoprene photo-oxidation products induced deviations in behavior relative to pure ammonium sulfate. Compared to an efflorescence relative humidity (ERH) of 30 to 35% for pure ammonium sulfate, efflorescence was eliminated for mixed aqueous particles having organic volume fractions ε of approximately 0.6 and greater. Compared to a deliquescence relative humidity (DRH) of 80% for pure ammonium sulfate, the DRH steadily decreased for increasing ε, approaching a DRH of 40% for ε of 0.9. Parameterizations of the DRH(ε) and ERH(ε) curves were as follows: DRH(ε)= Σ i ci,d xi valid for 0 ≤ ε ≤ 0.86 and ERH(ε)= Σ i ci,e xi valid for 0 ≤ ε ≤ 0.55 for the coefficients c0,d= 80.67, c0,e = 28.35, c1,d= −11.45, c1,e = −13.66, c2,d = 0, c2,e = 0, c3,d = 57.99, c3,e = −83.80, c4,d = −106.80, and c4,d = 0. The molecular description that is thermodynamically implied by these strongly sloped DRH(ε) and ERH(ε) curves is that the organic isoprene photo-oxidation products, the inorganic ammonium sulfate, and water form a miscible liquid phase even at low relative humidity. This phase miscibility is in contrast to the liquid-liquid separation that occurs for some other types of secondary organic material. These differences in liquid-liquid separation are consistent with a prediction recently presented in the literature that the bifurcation between liquid-liquid phase separation versus mixing depends on the oxygen-to-carbon ratio of the organic material. The conclusions are that the influence of secondary organic material on the hygroscopic properties of ammonium sulfate varies with organic composition and that the degree of oxygenation of the organic material, which is a measurable characteristic of complex organic materials, is an important variable influencing the hygroscopic properties of mixed organic-inorganic particles.

scholarly journals Rapid formation of isoprene photo-oxidation products observed in Amazonia

2009 ◽  
Vol 9 (3) ◽  
pp. 13629-13653 ◽  
Author(s):  
T. Karl ◽  
A. Guenther ◽  
A. Turnipseed ◽  
P. Artaxo ◽  
S. Martin
Keyword(s):  
Atmospheric Chemistry ◽  
Global Climate ◽  
Oxidative Capacity ◽  
Oxidation Products ◽  
Lower Atmosphere ◽  
Peroxy Radicals ◽  
Aerosol Formation ◽  
Photo Oxidation ◽  
Voc Oxidation ◽  
Rapid Formation

Abstract. Isoprene represents the single most important reactive hydrocarbon for atmospheric chemistry in the tropical atmosphere. It plays a central role in global and regional atmospheric chemistry and possible climate feedbacks. Photo-oxidation of primary hydrocarbons (e.g. isoprene) leads to the formation of oxygenated VOCs (OVOCs). The evolution of these intermediates affects the oxidative capacity of the atmosphere (by reacting with OH) and can contribute to secondary aerosol formation, a poorly understood process. An accurate and quantitative understanding of VOC oxidation processes is needed for model simulations of regional air quality and global climate. Based on field measurements conducted during the Amazonian aerosol characterization experiment (AMAZE-08) we show that the production of certain OVOCs (e.g. hydroxyacetone) from isoprene photo-oxidation in the lower atmosphere is significantly underpredicted by standard chemistry schemes. A recently suggested novel pathway for isoprene peroxy radicals could explain the observed discrepancy and reconcile the rapid formation of these VOCs. Furthermore, if generalized our observations suggest that prompt photochemical formation of OVOCs and other uncertainties in VOC oxidation schemes could result in substantial underestimates of modelled OH reactivity that could explain a major fraction of the missing OH sink over forests which has previously been attributed to a missing source of primary biogenic VOCs.

scholarly journals Phospholipid oxidation products in ferroptotic myocardial cell death

2019 ◽  
Vol 317 (1) ◽  
pp. H156-H163 ◽  
Author(s):  
Aleksandra Stamenkovic ◽  
Grant N. Pierce ◽  
Amir Ravandi
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Myocardial Cell ◽  
Oxidation Products ◽  
Oxygen Species ◽  
New Therapeutic Approaches

Cell death is an important component of the pathophysiology of any disease. Myocardial disease is no exception. Understanding how and why cells die, particularly in the heart where cardiomyocyte regeneration is limited at best, becomes a critical area of study. Ferroptosis is a recently described form of nonapoptotic cell death. It is an iron-mediated form of cell death that occurs because of accumulation of lipid peroxidation products. Reactive oxygen species and iron-mediated phospholipid peroxidation is a hallmark of ferroptosis. To date, ferroptosis has been shown to be involved in cell death associated with Alzheimer’s disease, Huntington’s disease, cancer, Parkinson’s disease, and kidney degradation. Myocardial reperfusion injury is characterized by iron deposition as well as reactive oxygen species production. These conditions, therefore, favor the induction of ferroptosis. Currently there is no available treatment for reperfusion injury, which accounts for up to 50% of the final infarct size. This review will summarize the evidence that ferroptosis can induce cardiomyocyte death following reperfusion injury and the potential for this knowledge to open new therapeutic approaches for myocardial ischemia-reperfusion injury.

Influence of Diene Content on the Photodegradation of Ethylene-Propylene-Diene (EPDM) Elastomers

2006 ◽  
Vol 514-516 ◽  
pp. 877-881 ◽  
Author(s):  
Gabriela Botelho ◽  
Arlete Queirós ◽  
Manuela A. Silva ◽  
Maria João Conceição
Keyword(s):  
Ftir Spectroscopy ◽  
Carbonyl Compounds ◽  
Oxidation Products ◽  
Ethylene Propylene ◽  
Photo Oxidation

The photodegradation of EPDM based on dicyclopentadiene was followed by FTIR spectroscopy and the main photo-oxidation products were identified by derivatization reactions. It could be found that the photodegradation is initiated at the diene with formation of α,β–unsaturated carbonyl compounds and is then propagated to the ethylene-propylene segments. The propagation reactions are accelerated and, hence, the rate of photodegradation increases with the diene content.

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