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Toxicology Studies of Semiconductor Nanomaterials: Environmental Applications
Published in Suresh C. Pillai, Yvonne Lang, Toxicity of Nanomaterials, 2019
T. P. Nisha, Meera Sathyan, M. K. Kavitha, Honey John
Covalent binding of biomolecules with nanosemiconductors can be made possible by using coupling agents like carbodiimide reagents (Chan et al., 1998). Most biomolecules contain amino and carboxyl groups. The reaction between these groups to form amide linkage can be catalysed by carbodiimide reagents. As an example, InP/ZnS semiconductor QDs were activated with dicyclohexylcarbodiimide (DCC) to yield a carboxylated intermediate which can react with the amino group of folic acid. These folate InS/ZnS conjugates were used for folate receptor-mediated delivery. Similar to carbodiimide conjugation, other strategies that are capable of covalent binding biomolecules to QDs include amine sulfhydryl reaction (Hildebrandt, 2011) and aniline-catalysed hydrazone (Blanco-Canosa et al., 2010) reactions (Figure 4.9).
Topical Anesthetics
Published in Marwali Harahap, Adel R. Abadir, Anesthesia and Analgesia in Dermatologic Surgery, 2019
The amide anesthetics have an amide linkage between the aromatic ring and the intermediate chain. They are primarily enzymatically metabolized in the liver. Amide anesthetics are rare sensitizers (Fig. 1).
Local Anesthetics
Published in Jeffrey R. Marcus, Detlev Erdmann, Eduardo D. Rodriguez, Essentials of CRANIOMAXILLOFACIAL TRAUMA, 2014
Alexander C. Allori, Dunya M. Atisha, Jeffrey R. Marcus
Amino ester anesthetics have an ester linkage in place of the amide linkage. They are metabolized by plasma cholinesterases, which yield metabolites (such as PABA) with slightly higher allergenic potential. Examples of ester anesthetics are cocaine, procaine, chloroprocaine, tetracaine, and benzocaine.
Synthesis of a targeted, dual pH and redox-responsive nanoscale coordination polymer theranostic against metastatic breast cancer in vitro and in vivo
Published in Expert Opinion on Drug Delivery, 2022
Monireh Falsafi, Naeimeh Hassanzadeh Goji, Amir Sh. Saljooghi, Khalil Abnous, Seyed Mohammad Taghdisi, Sirous Nekooei, Mohammad Ramezani, Mona Alibolandi
For fabricating a targeted-system with aptamer, amine-modified AS1411 aptamer was covalently linked to the free carboxylic acid groups of the PEG moiety activated with EDC/NHS in the VEP copolymer. The aptamer conjugation was carried out by the condensation of activated carboxylic acids with amine groups, forming an amide linkage. This technique is one of the most frequently used coupling strategy for the conjugation of synthetic polymers with biomolecules [20]. In particular, activation of carboxyl groups of polymers (here VEP copolymer) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) in the presence of N-hydroxy-succinimide (NHS), followed by coupling it to an amine-modified aptamer (here NH2-AS1411), has been reported previously [62,63]. During this stage of process, a little amount of DOX was released from VEP-nCP@DOX, thus encapsulation efficiency and loading content for Apt-VEP-nCP@DOX were calculated to be 51% ± 1 and 25% ± 3, respectively.
Co-drug of isoniazid and sulfur containing antioxidant for attenuation of hepatotoxicity and treatment of tuberculosis
Published in Drug and Chemical Toxicology, 2022
Neha V. Bhilare, Suneela S. Dhaneshwar, Kakasaheb R. Mahadik, Arunava Dasgupta
Conjugation of INH with alpha-lipoic acid improved the partition coefficient of the co-drug LI to 0.31. The result of the partition coefficient of co-drug was in agreement with its determined aqueous solubility (91 mg/mL). Newly formed amide linkage was confirmed through IR, where the characteristic amide C = O stretch and NH-stretch were detected at 1698 cm−1 and 3393 cm−1 respectively. The C = O stretch of the aromatic amide of INH moiety was observed at 1673 cm−1. The absence of C = O/OH stretching of the carboxylic group of alpha-lipoic acid further confirmed the formation of an amide linkage. Various other distinctive bands, such as the C–N stretch of pyridine ring at 1573 cm−1 and N–N wag of hydrazinic chain at 759 cm−1 further confirmed the structure of LI. The formation of amide was also confirmed by 1H-NMR spectra, where the δ values for protons of two amide bonds appeared at δ 10.38 as a singlet. The δ values for protons of INH backbone: 4 protons of pyridine ring (δ 7.83–8.80), as well as chemical shifts for protons of dithiolan backbone (δ 2.21–3.61), further confirmed the structure of LI. Predicted molecular weight and number of carbon atoms of LI were in accordance with the results of mass spectroscopy, elemental analysis and 13C-NMR.
Hyaluronan-modified nanoparticles for tumor-targeting
Published in Expert Opinion on Drug Delivery, 2019
Yu Sakurai, Hideyoshi Harashima
There are two methods for modifying HA, namely, electrostatic interactions and covalent conjugation. Since HA is a negatively charged polysaccharide, cationic NPs can be electrostatically associated with the molecule. It appears that approximately 30% of HA-NPs were formulated by electrostatic interactions and the remainder by chemical modification. In them most cases, the carboxylic group in Gln or the 6ʹ-OH group in GlcNAc are used to this chemical modification (Figure 3) [54]. Specifically, a formation of amide linkage between carboxylate in HA and amine in the compounds is the most frequently reported form. In some reports, a primary amine is used for conjugation to the end of HA via reductive amination of the end of HA. oxidation of Gln by sodium periodate NaIO4, which results in the formation of an aldehyde group. When HA was intra- and inter-molecular cross-linked with linking agents such as glutaraldehyde, HA forms a nanogel [55]. Through these modifications, moieties such as polymers and lipids can be conjugated to form NPs. Cargos of HA-NPs are variable: small molecules (most of which are doxorubicin; DOX, docetaxel; DTX, paclitaxel; PTX), fluorescent probe (fluorescent dye, quantum dots (QDs)) and nucleic acids (plasmid DNA; pDNA, small interfering RNA; siRNA). Base materials are selected to form NPs with appropriate size and properties and to load these therapeutics, including lipid nanoparticles (LNPs), micelles, emulsions, inorganic NPs and so on.