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Basics of toxicology
Published in Chris Winder, Neill Stacey, Occupational Toxicology, 2004
An example of the most common of these reactions, glucuronidation, is shown in Figure 2.7. The products of phase II reactions are often far more water soluble than the substrates, thereby promoting the overall excretion of the chemical. The glucuronidation process uses uridine-5’-diphospho-α-d-glucuronic acid (UDP-GA) as a cofactor and is carried out mainly in the endoplasmic reticulum of the liver.
Sedation, analgesia and patient observation in interventional radiology
Published in William H. Bush, Karl N. Krecke, Bernard F. King, Michael A. Bettmann, Radiology Life Support (Rad-LS), 2017
Jeffrey E. Quam, Michael A. Bettmann
With regard to clinical use, morphine and meperidine (Demerol®) play an important role as opiate narcotics for longer-term pain control, but have been largely replaced by fentanyl (Sublimaze®) and its congeners, sufentanil (Sufenta®) and alfentanil (Alfenta®), for systemic analgesia during percutaneous interventional procedures. One reason for this transition is the increased lipophilicity of these agents (fentanyl is 7000 times more lipophilic than morphine). This leads to much more rapid penetration into the CNS, more rapid onset of action, and thus more reliable and more reproducible analgesia. Morphine is metabolized in the liver by conjugation with glucuronic acid. One of the products of this metabolism is morphine-6-glucuronide. Compared to morphine, this metabolite is both more potent and has a longer effective half-life. This makes accurate titration for the desired analgesic effect much more difficult without introducing an increased risk of hazardous side-effects. A metabolite of meperidine, nor-meperidine, has been shown to cause tremors and seizures.40 Fentanyl and its congeners have much shorter effective half-lives than morphine or meperidine, and have little significant effect from persisting active metabolites, allowing excellent titration of analgesia. In addition, fentanyl causes less spasm of the sphincter of Oddi and less nausea and vomiting than is commonly observed with morphine. Finally, fentanyl and its congeners cause little if any histamine release, and are thus preferred for patients with known reactive airway disease or hypotension. Only minimal cardiovascular depression is observed with fentanyl, even at high doses. However, it can cause slight bradycardia due to increased vagal tone. An unusual chest-wall rigidity can be seen with rapid injections of high doses of fentanyl. This appears to be due to stimulation of the spinal inspiratory motor neurons, creating a sustained inspiration that may lead to respiratory compromise.41
Separation and characterization of cellulose from sugarcane tops and its saccharification by recombinant cellulolytic enzymes
Published in Preparative Biochemistry & Biotechnology, 2021
Kaustubh Chandrakant Khaire, Vijayanand Suryakant Moholkar, Arun Goyal
The monosaccharide composition analysis of cellulose separated from SCT was performed by treating 5 mg separated cellulose with 1 mL of 2 M Tri-fluro-acetic acid (TFA) in a 1.5 mL Eppendorf tube and by heating in a boiling water bath for 3 h. The hydrolyzed cellulose was kept in hot air oven at 80 °C for 12 h to remove the remaining residual TFA. The dried TFA hydrolyzed cellulose sample was mixed in 500 µL degassed Milli-Q water and then filtered through a syringe filter using by PVDF membrane (Pore size: 0.22 µm). The filtered sample was transferred to the HPLC vials (Axiva Sichem Biotech, India) and analyzed for monosaccharides present by High Performance Liquid Chromatography (HPLC) (UFLC, Prominence, Shimadzu, Japan) using a RI detector. 10 µL of TFA treated SCT cellulose was loaded and passed through the guard column (50 mm × 7.8 mm), followed by passing through the connected monosaccharide separation column phenomenex Rezex ROA (H+) (300 mm × 7.8 mm). The elution was performed by 0.005 N H2SO4 solution at 70 °C at 0.5 mL/min flow rate for 90 min run time per sample. 1 mg/mL each of glucose, xylose, arabinose or glucuronic acid was used as standard for composition determination.
Plant gums for sustainable and eco-friendly synthesis of nanoparticles: recent advances
Published in Inorganic and Nano-Metal Chemistry, 2020
Gum arabic, a natural polysaccharide derived from exudates of A. senegal and A. seyal trees,[99] is one of the most widely used amphiphilic hydrocolloids in the food industries.[61,100] This gum is well-known for its complex chemical structure composed mainly of a highly branched polysaccharide and two protein–polysaccharide complexes as minor component.[99] Highly branched polysaccharide consisting of β-(1→3) galactose backbone with linked branches of arabinose and rhamnose, which terminate in glucuronic acid (found in nature as magnesium, potassium, and calcium salt). Second part made up arabinogalactan-protein complex in which polysaccharide moieties were linked through both O-serine and O-hydroxyproline.[101] This part of gum arabic is susceptible to bacteria polysaccharide lyase family that is specific for the L-rhamnose-alpha1,4-D-glucuronic acid linkage that caps the side chains of arabinogalactan–protein complex.[102] The third part contains highest protein content (around 50 w/w%), is a glycoprotein which varies in its amino acids composition from that of the arabinogalactan-protein complex (GAGP -gum arabic glycoprotein).[99]
Evaluation of hard capsule application from seaweed: Gum Arabic-Kappa carrageenan biocomposite films
Published in Cogent Engineering, 2020
Fatmawati Adam, Jurida Jamaludin, Siti Hana Abu Bakar, Ruwaida Abdul Rasid, Zulkafli Hassan
Gum Arabic (GA) consists of galactose (40% of residues), arabinose (24%), rhamnose (13%) and glucuronic acid (23%) (Espinosa-andrews et al., 2007). It was found in plant based as a polysaccharide acid rich in calcium, magnesium, and potassium salts (Islam et al., 1997). GA has a complex structure and long chain with more than one different repeating monosaccharide units (Lopez-Torrez et al., 2015). Besides, it was used as an emulsifier (Y. Liu et al., 2014), tablet-coating agent (Lu et al., 2003) and as crosslinker in scaffold development (Sarika et al., 2014). GA is also suitable for edible film formation. However, it must be mixed with other materials such as protein (Li, Zhu, et al., 2014), starch (Apandi et al., 2013), and alginate (Tsai et al., 2017) to form edible film. This is because pure GA film exhibits brittleness problem (Jamaludin et al., 2017) and can crack easily. Thus, this work is to investigate the GA and semi refined κ-carrageenan (SRC) biocomposite film to improve the morphology and mechanical properties of the hard capsules, to seek its potential in the application of hard capsule.