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An Overview of Molecular Nutrition
Published in Nicole M. Farmer, Andres Victor Ardisson Korat, Cooking for Health and Disease Prevention, 2022
Vincent W. Li, Catherine Ward, Delaney K. Schurr
Once in the stomach, gastric lipase, amongst other digestive enzymes, is released. However, gastric lipase is responsible for only the initial and minimal breakdown of ingested fats. The large majority of fat digestion does not occur in the stomach, but later on in the small intestine. Once released from the food matrix, fat is now bound to bile salts to undergo its main form of digestion in the small intestine. Pancreatic lipase works to break down triglyceride fats into monoglycerides and fatty acids. The efficient activity of the lipase is dependent on the presence of bile salts on fat droplets. Multiple bile salts with the complexed triglyceride components spontaneously form micelles. Micelles then enter enterocytes where the bile is broken down and chylomicrons are packaged and extruded from the basolateral enterocyte wall to enter the lymphatics. This is the mechanism for absorption of triglycerides which represent 90% of dietary fat. Dietary cholesterol undergoes a similar process except it requires a transport protein in order to enter the enterocyte. Lastly, MCTs, such as coconut oil, when extruded from the enterocyte go directly into the blood stream, by passing the lymphatic system. Therefore, MCTs are suspected of having a favorable metabolic profile.
Functions of the Liver
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
After absorption, fat is either metabolized to yield energy or stored as triglyceride in fat deposits. Some 50% of triglycerides derived from the diet are hydrolysed to glycerol and fatty acids, whereas 40% are partially hydrolysed to monoglycerides. Short-chain fatty acids (fewer than 12 carbon atoms) are transported directly to the liver via the portal vein without re-esterification. Longer chain fatty acids are re-esterified after absorption and then covered with a phospholipid and protein layer to form chylomicrons. Lipoprotein lipases hydrolyse the chylomicrons, producing free fatty acids that may be taken up by adipocytes for storage or metabolized within body tissues as an energy source.
Introduction
Published in Margit Hamosh, Lingual and Gastric Lipases: Their Role in Fat Digestion, 2020
Glycerides and nonphosphorus-containing lipids which result from the esterification of glycerol and fatty acids (Figure 1). Three forms occur in nature. Triglycerides (neutral fat) are the most abundant lipids in animal tissue and serve as an important energy source. All three of the carbon molecules of glycerol are sterified with fatty acids. Monoglycerides and diglycerides are compounds resulting from ester links between glycerol and one or two fatty acids.
Multi-strategic approaches for enhancing active transportation using self-emulsifying drug delivery system
Published in Journal of Drug Targeting, 2022
The bile salts and enzymes present in the intestinal tract break down the lipid excipients of SEDDS leading to structural change and alteration in the bond strength, as a result, there is rapid drug release before the pre-determined time. Furthermore, triglycerides are commonly used in SEDDs preparation due to their resemblance to the physiological lipids; however, it makes them highly pre-disposed to the intestinal enzymes than monoglycerides [85]. The exenatide-loaded SEDDS prepared with the Labrafil-1944 and Capmul PG-8 showed a sustained in vivo drug release for 6 h as both the surfactants lack a triglyceride group [65]. The lipid phase of SEDDS presents as a barrier and inhibits penetration of enzymes and glutathione thus protecting the entrapped drug from degradation [86].
Drug delivery to the intestinal lymph by oral formulations
Published in Pharmaceutical Development and Technology, 2022
Takayuki Yoshida, Hiroyuki Kojima, Kazuhiro Sako, Hiromu Kondo
The forms of lipids (mono-, di-, and triglycerides, or fatty acids) affect delivery efficiency and their rates of transport into the lymph (Vahouny and Treadwell 1959; Porter and Charman 2001; Banno et al. 2002; Trevaskis et al. 2008). Di- and triglycerides may be degraded by lipases in the intestinal tract before absorption (Porter and Charman 2001; Trevaskis et al. 2008; Yáñez et al. 2011). In contrast, a degradation step is not required for the transport of 2-monoglycerides and fatty acids (Porter and Charman 2001; Trevaskis et al. 2008; Yáñez et al. 2011). For example, the lymphatic recovery rates of docosahexaenoic acids after 30 h of emulsion dosing in rats are as follows: monoglycerides (63% dose), diglycerides (40%), triglycerides (27%) (Banno et al. 2002). Emulsions of fatty acids increase the amounts of lipids in the lymph compared with those of triglycerides (2.46-fold, 1.62-fold, and 1.13-fold for C18:0, C18:1, and C18:2, respectively) in rats (Vahouny and Treadwell 1959).
The tiny big world of solid lipid nanoparticles and nanostructured lipid carriers: an updated review
Published in Journal of Microencapsulation, 2022
Heidi M. Abdel-Mageed, Amira E. Abd El Aziz, Saleh A. Mohamed, Nermeen Z. AbuelEzz
A decade after introducing SLN, the second generation of lipid NP, the nanostructured lipid carriers (NLC) were introduced (Müller et al.2002a). It was described as an improved formulation of SLN. NLC composition comprised small amounts of liquid lipids (oils) at room temperature, to create structural rearrangements of the lipid matrix. Oleic acid is the most commonly used liquid lipid. Also, Monoglycerides and diglycerides such as Capmul® MCM and Triglycerides such as Migylol® 812 are widely used. Various natural oils such as castor, sunflower, pomegranate seed, and soybean oils are used for NLC preparation as well (Subramaniam et al.2020). The oils in NLC work to reduce the maturation and crystallinity of the solid lipid core of SLN, thus preventing drug expulsion from the matrix and enhancing the drug encapsulation efficiency and the Physico-chemical long-standing stability of NP (Müller et al.2002b). A comparison between the composition of LNP and examples of different constituents used in the preparation of SLNise is presented in Figure 5.