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Lipidomic Insight into Membrane Remodeling in Aging and Neurodegenerative Diseases
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
Lipids are biomolecules varying in the structure of their head groups, the nature and number of carbon–carbon bonds (single or double C=C bonds) in lipophilic fatty acids chains, and all ligands. Lipids are involved in many metabolic pathways and are responsible for energy storage. Different classes and derivatives, including fatty acids, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, saccharolipids, and polyketides are presented in Figure 7.2 [15,16].
A Brief Background
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
Organic reactions are used to synthesise drugs. Considerations of the stereochemistry are obviously vital in the design of new medicines. In cases where one of the two stereoisomers is the active drug, an asymmetric synthesis is required where special measures are taken to ensure stereospecificity. With knowledge of the characteristic reactions that different functional groups display, organic chemists can synthesise a target drug molecule from the relevant readily available starting materials. To build a target molecule, making carbon-carbon bonds is essential. Functional groups that will undergo addition reactions are useful for this purpose. To ensure strong interactions with the drugs’ biological target, a particular functional group may be needed in the molecule. Here, a substitution reaction may be relevant. Ultimately, a drug molecule is made with the correct size, shape, correctly positioned functional groups, and chemical properties that will interact with the biological system to produce a biological response. A selection of functional groups that are key to organic synthesis are shown in Figure 1.2. Whether the compound acts as a medicine or a poison depends on the dose level of the compound. This can be described by the drugs therapeutic index, which is a measure of a drugs beneficial effect at low dose versus its harmful effects at high dose. No drug is absolutely harmless and drugs may vary in the side effects they have.
Structures and Properties of Self-Assembled Phospholipids in Excess Water
Published in E. Nigel Harris, Thomas Exner, Graham R. V. Hughes, Ronald A. Asherson, Phospholipid-Binding Antibodies, 2020
At temperatures above Tm, the mixed interdigitated bilayer transforms into the partially interdigitated bilayers with the short chain from one leaflet pairing with the longer acyl chain counterpart contributed by the opposing leaflet. The acyl chains in the bilayer at T>Tm no longer remain in the highly ordered gel-like state with a nearly all-trans conformation. In contrast, they become highly dynamic with considerable orientational fluctuations and trans → gauche isomerizations about the carbon-carbon bonds. Consequently, closest lateral van der Waals contact interactions among phospholipid acyl chains in the bilayer are no longer possible, leading to a liquid-like disordered state for the bilayer interior. This highly disordered state for the bilayer at T>Tm is called the liquid-crystalline or fluid state, generally abbreviated the L„ phase. It should be emphasized, however, that the acyl chains are partially interdigitated in the Lα phase. In fact, C(18):C(10)PC with ΔC/CL-0.56 is the first example in which the acyl chain interdigitations have been found for the phospholipid bilayer in both the gel and liquid-crystalline states.
Modeling percutaneous absorption for successful drug discovery and development
Published in Expert Opinion on Drug Discovery, 2020
Hanumanth Srikanth Cheruvu, Xin Liu, Jeffrey E. Grice, Michael S. Roberts
Penetration enhancers can disrupt the SC barrier by altering skin lipids (extraction/fluidization/phase separation/polarity alteration) and/or proteins and/or by affecting partitioning behavior [14,91,122] of chemicals thereby affecting SC flux (Jsc). The increase in chemical penetration can be expressed in terms of an enhancement ratio (ER), the ratio of chemical penetration with and without enhancer. Some structural aspects that have been found to be indicative (although not definitive) of penetration enhancer capability include: Solvents with methyl groups bonded to heteroatoms or to CH2 groups (dimethyl sulfoxide, N-methyl-2-pyrrolidone, dimethylacetamide, and dimethylformamide) and carbon-carbon bonds in aliphatic rings (N-methyl-2-pyrrolidone, ɣ-butyrolactone) may act as permeability enhancers [124]Chemicals with carbon chain (CC) length >12 and 3 or 4 H-bonding atoms may act as enhancers [125]Solutes with high logP and fewer hydroxyl functional groups moving from end to center of an alkyl chain may act as potent enhancers [126]Chemicals with MW of 250–400, hydrogen bonding (HB) number of 2 to 4 and CC length of 11–14 may act as good enhancers (ER ≥10) [127]
Stimuli-responsive polyvinylpyrrolidone-NIPPAm-lysine graphene oxide nano-hybrid as an anticancer drug delivery on MCF7 cell line
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Maryam Ashjaran, Mirzaagha Babazadeh, Abolfazl Akbarzadeh, Soodabeh Davaran, Roya Salehi
Before in-vitro biological analysis, drug loading and release studies were investigated. Firstly, FU as an anticancer drug was chosen for loading drug on the prepared GO/NHs in PBS solution (pH 7.4). The nanocarrier in this study has several functional groups such as hydroxyl (–OH), carboxylic acid (–COO) and carbon-carbon double bond (C=C) in graphene oxide platform and other functional groups including carbonyl (C=O), amide (–CO–NH–), amine (–NH2) and carboxylic acid (–COOH) on the polymeric backbone and lysine grafting. On the other hand, FU has amide and double carbon-carbon bonds in its structure. After that, FU could be loaded easily on the prepared GO/NHs as a drug carrier via hydrogen bonding, electrostatic interaction, and physical interactions. Some of the drugs were loaded on the GO/NHs via hydrogen bonding or electrostatic physical interactions between polar groups on both structures. Besides, some of the drugs were loaded via π-π interaction between graphene oxide platform and C = C bonds in drug structure. While other parts of drugs were entrapped in the polymeric architecture by physical interactions. After calculation of the amount of drug loading and encapsulation efficiencies with mentioned formula in the experimental section, their amounts were obtained 7.28% and 72.89%, respectively and obtained FU-GO/NHs used as a drug carrier in the release study.
Nanostructured cubosomes in an in situ nasal gel system: an alternative approach for the controlled delivery of donepezil HCl to brain
Published in Journal of Liposome Research, 2019
Rahul P. Patil, Devlya D. Pawara, Chetan S. Gudewar, Avinash R. Tekade
With the recent developments in the technology, experience and expertise in the area of nano-pharmaceuticals, cubosome-based systems are being actively pursued as potential alternatives to non-common systems such as liposomes and niosomes (Rarokar et al.2016). Cubosomes are made up of a binary system of mono-olein and water, where the mono-olein acts as a precursor for lipid bilayer, which divides the hydrophilic regions of cubic phases. This binary system can self-assemble into thermodynamically stable bi-continuous, cubic, liquid-crystalline phases (Larsson 1983, Bei et al.2009). Heating is important also to form that cubic crystalline liquid. The hydrocarbons chains of the polar lipid tend to melt easily at lower temperature while the polar heads remain intact and bound together with strong hydrogen bonds (Larsson 2000). The carbon–carbon bonds are transformed from all trans to the gauche conformation in the liquid crystalline state (Garti et al.2012). The combination between the disordered melted atoms and the highly ordered planar layers is main characteristic of the cubosomal structure. Incorporation of drugs into the complex internal domains of these structures can facilitate a diffusion-controlled release of the drug into the surrounding external aqueous environment and may provide new ways to modify pharmacokinetic profiles using lipid-based systems (Rarokar et al.2016).