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Nanostructures for Improving the Oral Bioavailability of Herbal Medicines
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
The small intestine represents the longest and the most important part of the GI tract for digestion and absorption of drugs and nutrients. It consists of the duodenum, the jejunum, and the ileum. Due to the presence of bicarbonate that neutralizes the acids emptied from the stomach, the duodenum has a pH of about 6–6.5. An enzyme containing pancreatic juice is secreted into the duodenum from the bile duct, which results in the hydrolysis of proteins, fats, and other foods. The complex fluid at the duodenum helps in the solubilization of many drugs with limited aqueous solubility, however, the presence of proteolytic enzymes results in the instability and inadequate absorption of protein drugs. The region between the duodenum and the ileum is the jejunum, which has broader and thicker walls than the ileum. The ileum is the terminal part of the small intestine, having a pH of about 7 with the distal part as high as 8, and the presence of bicarbonate secretion helps in the dissolution of fats and hydrophobic drugs (Shargel et al., 2005). Compared to the jejunum, the folds in the ileum are lower and sparser, however, the ileum has distinctive lymphoid tissue patches, called Peyer’s patches, which are the most important structural units of the gut associated with lymphoid tissue (GALT).
Biodegradation Properties
Published in Chih-Chang Chu, J. Anthony von Fraunhofer, Howard P. Greisler, Wound Closure Biomaterials and Devices, 2018
Since all commercial synthetic absorbable sutures have ester linkages, they are subject to hydrolysis as simple organic esters. However, is the hydrolytic degradation of these absorbable sutures affected by the pH of the medium in the same way that it is affected in the simple organic esters? Are the reversibility and irreversibility of hydrolysis in simple organic esters applicable to polymeric systems? How does the tensile strength of the suture material change with pH of a medium? Furthermore, it is important to understand the pH-dependent degradation of these suture materials, because surgical suture materials should be able to retain adequate strength under all possible physiologic and pathologic conditions. It is known that the pH of gastric juice in the stomach can reach as low as 0.9 to 1.5, while pancreatic juice in the duodenum ranges from 7.5 to S.2.93,94 The urinary pH often ranges from 4.5 to 8.0.95 In the latter case, although the reported data are in conflict, absorbable sutures should be used. Nonabsorbable sutures should not be used in the urinary tract because their presence incites the formation of urinary calculi.96 This peculiar requirement in urologic surgery further indicates the importance of studying the pH-dependent degradation of synthetic absorbable sutures. To answer these questions, a series of studies have been reported.24,25,97,98
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2016
David J. Baker, Naima Bradley, Alec Dobney, Virginia Murray, Jill R. Meara, John O’Hagan, Neil P. McColl, Caryn L. Cox
The pancreas is a gland which sends its secretions in to the blood stream and also into the duodenum. The secretion of insulin and glucagon, which are necessary for the control of blood sugar in the human body, is from the pancreas. The juices from the pancreas that enter the duodenum, known as the pancreatic juices, contain the enzymes trypsinogen and chymotrypsinogen, which are precursors of the protein-splitting enzymes trypsin and chymotrypsin. These promote the digestion of food in the small intestine after leaving the stomach.
Phytofabrication of silver and zinc oxide nanoparticles using the fruit extract of Phyllanthus emblica and its potential anti-diabetic and anti-cancer activity
Published in Particulate Science and Technology, 2023
Alpha-amylase is a digestive enzyme found primarily in the saliva and pancreatic juice and is considered to be most significant due to its vital role in the hydrolyzes α-bonds of large α-linked polysaccharides and the adsorption of glucose during digestion. Targeting this enzyme and suppressing its action will slow down the digestion of carbohydrates, lower glucose absorption, and prevents high postprandial blood glucose levels. Hence, inhibition of the alpha-amylase enzyme is considered a potential avenue for the regulation of blood sugar levels in persons suffering from diabetes (Lava et al. 2021; Perumalsamy and Krishnadhas 2022). The potential Alpha-amylase inhibition of ethanol fruit extract of P. emblica, PE-AgNPs, PE-ZnONPs, and metformin is demonstrated in Figure 10. Metformin is used as a standard drug that showed inhibitory effects on alpha-amylase enzyme activity with an IC50 value of 130.73 ± 1.11 µg/mL. The calculated IC50 of ethanol fruit extract of P. emblica, PE-AgNPs, and PE-ZnONPs is 220.44 ± 1.34, 170.60 ± 0.94, and 160.82 ± 0.88 µg/mL, respectively. The inhibition of Alpha-amylase enzyme is dose-dependent manner as the concentration increases the amount of enzyme activity was inhibited. Accordingly, the biosynthesized PE-AgNPs, and PE-ZnONPs nanoparticles showed significant antidiabetic activity compared to that of the extract.