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Chemosensory Disorders and Nutrition
Published in Alan R. Hirsch, Nutrition and Sensation, 2023
Carl M. Wahlstrom, Alan R. Hirsch, Bradley W. Whitman
Olfactotoxins may affect the olfactory system in a multitude of ways. They can be directly cytotoxic to the epithelium. Or, a pyrolytic chemical may combine with biological chemicals to produce an olfactotoxin. Ammonia, for instance, combines with water from the olfactory mucosa to form ammonium hydroxide, which can cause liquification of the mucosal surface. Another example is chlorine; this gas combines with water in the olfactory mucosa inducing the formation of free radicals. Olfactotoxins may overwhelm xenobiotic mechanisms, so that ordinarily neutral endogenous or exogenous substances have toxic effects. Or, the olfactotoxins may act directly on olfactory nerve cells or stem cells, preventing the olfactory nerve from regenerating. Finally, the pyrolytic byproduct may inhibit the flow of mucous, impeding the removal of all toxins in a cellular environment.
Commercial Scale Manufacturing of Oligonucleotides Under Good Manufacturing Practices
Published in Eric Wickstrom, Clinical Trials of Genetic Therapy with Antisense DNA and DNA Vectors, 2020
Jose E. Gonzalez, Richard G. Einig, Patricia Puma, Timothy P. Noonan, Paul E. Kennedy, Bruce G. Sturgeon, Bing H. Wang, Jin-yan Tang
Nonionic methylphosphonate oligonucleotides (Hogrefe, et al., 1993) may be synthesized as a pure methylphosphonate, or as a product which combines regions containing methylphosphonates and standard phosphorothioates or phosphodiesters. Such products are referred to as "chimeric" molecules. These molecules present a challenge to cleavage, deprotection, and to some extent purification, since the methylphospho-nate portions of a chimeric product are relatively less stable to basic pH than the non-methylphosphonate portions. For this reason, concentrated ammonium hydroxide, successfully used with first generation oligonucleotides (Figure 1), is not ideal for cleavage/deprotection. Using a gentler deprotection agent such as ethyl-enediamine in ethanol gives better results.
High-Performance Liquid Chromatography
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Joel J. Kirschbaum, Adorjan Aszalos
Erythromycin was determined using an octadecylsilane column with a mobile phase of methanol-water-ammonium hydroxide (80:19.9:0.1) flowing at 1.4 ml/min into a refractive index detector [441a]. Ammonium hydroxide was used to suppress ionization of the basic group.
Silibinin Improves TNF-α and M30 Expression and Histological Parameters in Rat Kidneys After Hepatic Ischemia/Reperfusion
Published in Journal of Investigative Surgery, 2018
Georgios Kyriakopoulos, Alexandra K. Tsaroucha, Georgia Valsami, Maria Lambropoulou, Nikolaos Kostomitsopoulos, Eirini Christodoulou, Zacharias Kakazanis, Constantinos Anagnostopoulos, Christos Tsalikidis, Constantinos E. Simopoulos
Preparation of SLB-HP-β-CD lyophilized product was performed as previously described [23, 24] using a freeze-drying procedure and the neutralization method [25]. Briefly, 0.300 g of SLB (MW = 482.44) and 1.860 g of HP-β-CD (MW∼1540) (both purchased from Sigma Aldrich, Steinheim, Germany, purity > 99%) were weighed accurately, transferred in a 300 mL volumetric flask, and suspended with 200 mL of water (triple-de-ionized water from Millipore was used for all preparations). Small amounts of ammonium hydroxide were then added under continuous stirring and pH monitoring until complete dissolution, and pH adjustment to a value between 9 and 10 was obtained. The resulting solution at a molar ratio of 1:2 was thereafter freeze-dried using a Kryodos-50 model Telstar lyophilizer.
Impact of nanosizing on the formation and characteristics of polymethacrylate films: micro- versus nano-suspensions
Published in Pharmaceutical Development and Technology, 2021
Sakib Saleem Yousaf, Abdullah Isreb, Iftikhar Khan, Enosh Mewsiga, Abdelbary Elhissi, Waqar Ahmed, Mohamed A. Alhnan
Whilst aqueous coating nano-suspensions offer several advantages, processing of these formulations in addition to the use of high concentrations of alkalinising agents, necessitate the use of anti-tacking and plasticising agents (typically 40–60% w/w (based upon polymer weight) (Huyghebaert et al. 2005; Bando and McGinity 2006; Ibekwe et al. 2006). As plasticiser concentration is raised, increased tackiness and potential plasticiser migration may also arise (Obara and Kokubo 2008). Moreover, the usage of alkalinising agents (e.g. ammonium hydroxide) in enteric aqueous suspensions is also associated with pitfalls and risks. First, in addition to being corrosive and toxic, the storage of large quantities of ammonium hydroxide for usage, involves a high risk of environmental damage upon potential release (Puglionesi 1998). Second, the presence of partially neutralized acidic polymers in aqueous enteric coating formulations gives rise to higher swelling rates, on contact with gastric fluid, resulting in potential compromise of film acid-barrier function (Stafford and Ag 1982; Béchard et al. 1995; Thoma and Bechtold 1999). Interest in enteric formulations is sustained for a number of reasons, however primarily relates to protection offered from the harsh environment of the gastrointestinal tract and also the preference for solid dosage forms as the principal choice when formulating drug products (Zhou and Li 2018; Nemeth et al. 2019). Thus far, there have been no literature reports of an enteric formulation, which is a true aqueous nano- suspension i.e. free from organic solvents in its production or alkalinising agents in its rendering.
In vitro and in vivo analysis of metabolites involved in the TCA cycle and glutamine metabolism associated with cisplatin resistance in human lung cancer
Published in Expert Review of Proteomics, 2021
Jiwei Guo, Jing Yu, Feng Peng, Jinzi Li, Zhirong Tan, Yao Chen, Tai Rao, Yicheng Wang, Jingbo Peng, Honghao Zhou
HPLC-grade acetonitrile, methanol, and acetic acid were purchased from Merck (Germany). Ammonium hydroxide [25% (w/v)] solution and ammonium acetate crystals were supplied by Fisher Scientific. D/L-2-Hydroxyglutaric acid disodium salt was purchased from Sigma-Aldrich (Shanghai, China). Succinate, α-KG, glutamine, and glutamate were obtained from the National Institutes for Food and Drug Control (Beijing, China). Stock solutions of the above analytes at 1 mg/mL were prepared in deionized water and filtered with a nitrocellulose syringe filter (0.45 μm). Working solutions for linearity and partial method validation were prepared by diluting the stock solutions with 50:50 (v/v) water/methanol.