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Methods of Protein Iodination
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
There is one prosthetic group in each molecule of enzyme that is a derivative64 of mesoheme 9. It is linked to the protein by an ester bond. Therefore, in contradistinction to the situation with hemoglobin, myoglobin, catalases, horseradish peroxidase, and cytochrome, it cannot be extracted by acetone/HC1. The prosthetic group interacts with the usual hemoprotein ligands59 (e.g., cyanide, fluoride, azide). Because these ligands compete with H2O2, they can be used to inhibit the enzyme. Binding of neither of these ligands affects the gross conformation of the protein.65
Local Anesthetics and Anesthetic Solutions: Classification, Mode of Action and Dosages
Published in Marwali Harahap, Adel R. Abadir, Anesthesia and Analgesia in Dermatologic Surgery, 2019
Ester-type local anesthetics are inactivated by plasma esterases, and amide-type ones have a mostly hepatic metabolism. However, articaine is an amide-type local anesthetic with an ester bond and is inactivated by plasma esterases.
Nanocarrier Technologies for Enhancing the Solubility and Dissolution Rate of Api
Published in Debarshi Kar Mahapatra, Sanjay Kumar Bharti, Medicinal Chemistry with Pharmaceutical Product Development, 2019
Ashwini Deshpande, Tulshidas S. Patil
Being an amphiphilic molecule, one portion is hydrophilic and the other is hydrophobic. These two portions can be linked by ether, amide or ester bond. Materials like amino acids, fatty acids, amides, alkyl esters, and alkyl ether surfactants can be used to prepare non-ionic surfactant vesicles.
Reduction of systemic exposure and side effects by intra-articular injection of anti-inflammatory agents for osteoarthritis: what is the safer strategy?
Published in Journal of Drug Targeting, 2023
Zuoxu Xie, Lu Wang, Jie Chen, Zicong Zheng, Songpol Srinual, Annie Guo, Rongjin Sun, Ming Hu
As mentioned previously (in Section 3), the long-term use of corticosteroids and inhibition of COX-1 via non-selective NSAIDs in the joint may accelerate the loss of cartilage and disease progression. Therefore, COX-2 selective inhibitors are the better candidates for IA injection therapy to relieve OA inflammation and pain. As shown in Figure 1, a locally active COX-2 (LA-COX-2) inhibitor could be designed and synthesised through a hydrolytic or phase II metabolic mechanism. Take meloxicam as an example, by using hydrolysis, the amide bond in the structure can be substituted with an ester bond to form meloxicam-E. Once meloxicam-E (or any other ester-containing LA-COX-2 inhibitors) is hydrolysed by the esterases, it will break into two inactive metabolites: meloxicam-E-H1 and meloxicam-E-H2. Celecoxib, on the other hand, can be modified with a phenolic group that could be metabolised by SULTs and UGTs. For example, the trifluoromethyl group of celecoxib can be replaced by the phenolic group to form Cele-OH. Cele-OH can then be inactivated to Cele-OH-sulphate and Cele-OH-glucuronide by SULTs and UGTs in the liver and kidney. As long as the phenolic active compounds are metabolised to glucuronides and sulphates, they will be secreted out of the body quickly. However, because of the fast clearance of free small molecules in the joint, a sustained-release formulation is necessary to gradually release the active compounds in the joint. Another advantage of a sustained-release formulation is that the formulation (i.e. PLGA microparticles) is able to protect the LAD from exposure to enzymes and water.
Factors affecting the dynamics and heterogeneity of the EPR effect: pathophysiological and pathoanatomic features, drug formulations and physicochemical factors
Published in Expert Opinion on Drug Delivery, 2022
Rayhanul Islam, Hiroshi Maeda, Jun Fang
Another approach is utilization of protease-cleavable linkers. Many tumors excrete various proteinases, among which plasminogen activator, cathepsin B, and cathepsin K have been well studied [89,91–93]. Linker peptides sensitive to these proteases can be used and in fact were proved effective in experimental models [89,91–93]. We utilized proteases from human colon cancer and mouse tumor tissues and compared the cleavability of different chemical bonds. We used PEG-conjugated drugs with different linker bonds including ether, ester, and amide bonds and found that the ester bond was more sensitive to cleavage and released free drug more than the amide bond did, and the ether bond was almost uncleavable [94]. As an important result, we found that human colon cancer tissue homogenates demonstrated more proteolytic activity than homogenates of most normal organs except the liver [94]. These findings supported the utilization of proteinases (or esterases) for tumor-selective drug design.
Design and evaluation of hyaluronic acid-coated PLGA nanoparticles of raloxifene hydrochloride for treatment of breast cancer
Published in Drug Development and Industrial Pharmacy, 2021
Kajol Bhatt, Pravin Patil, Parva Jani, Parth Thakkar, Krutika Sawant
FTIR spectra of pure drug, PLGA, HA, drug-loaded NPs, and drug-loaded HA-coated NPs are shown in Figure 4(a–e). FTIR of native RALH showed characteristic peaks of phenolic OH at 3144.5 cm–1, aromatic CH stretch at 2881.67 cm–1, C═O stretch at 1750 cm–1, phenyl ring (C═C stretch), C–O stretch at 1257.1 cm–1 and of benzothiophene at 806.06 cm–1. The PLGA spectrum showed characteristic peaks at 2998.46 cm–1 and 1749.87 cm–1 indicating O–H stretching and C═O stretching (due to alpha-substitution), respectively. The spectrum of HA showed characteristic peaks at 3323.3 cm–1, 1612.49 cm–1 and 1546.91 cm–1 and 1072.42 cm–1 marking the presence of O–H and N–H stretch, C═O stretch (corresponding to carboxylic groups in HA) and C═C stretch and C–O–C (ether) stretching, respectively. All the characteristic peaks of PLGA were retained with slight change in peak intensity in IR spectrum of RALH-loaded PLGA NPs, while characteristic peaks of RALH were absent indicating that the drug was completely incorporated in the PLGA NPs. From the spectrum of HA-coated PLGA NPs, it can be inferred that HA conjugated with PLGA by coupling agent, EDC, as HA-coated NPs exhibited peak of C═O group with high intensity at 1755.22 cm–1. This might be attributed to consumption of carboxylic groups of PLGA. Also the reduced intensity of –OH stretching implied the consumption of –OH groups of HA for ester bond formation with carboxylic groups of PLGA.