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What Are Sterols?
Sterols are essential components of the membranes of all eukaryotic organisms, controlling membrane fluidity and permeability. Sterols are the third class of lipids, which play multiple roles that either individually or collectively influence cell processes, and through charge and structure they are involved in DNA replication, protein translocation, cell recognition, signalling pathways, energetic, signal transduction, and cell trafficking. Sterols regulate biological processes and sustain the domain structure of cell membranes where they are considered as membrane reinforcers . What are the examples of sterols? Cholesterol is the main animal sterol, while β-sitosterol, campesterol, stigmasterol, brassicasterol, avenasterol, and stigmastenol are major plant sterols present in vegetable oils at much higher levels than…
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What Are Detergents?
Detergents are amphipathic molecules with a polar portion and a hydrophobic portion. Detergents respond to an aqueous environment following the same principles as do membrane lipids. What Are the Forms of Detergents? Detergents can exist in three environments in aqueous media. Detergents have a limited solubility in the aqueous phase, characterized by the CMC, or critical monomer concentration (or critical micelle concentration). Above the CMC, detergents form micelles. In the presence of membranes, detergents can also partition into the membrane. In the latter case, sufficient detergent will lead to transfer of membrane components, including membrane lipids and membrane proteins, into the detergent micelles. What can Detergents Used for? Detergent micelles can…
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The Route And Process Of Ocular Administration
The eye is a special sensory organ of the human body and an important part of the body. Ocular lesions are closely related to and interact with other tissue system lesions throughout the body. The special structure and physiological characteristics of the eye make ophthalmic drugs have their own characteristics in the way and route of administration. Most drugs enter the aqueous humor through the cornea, and then are distributed in surrounding tissues, such as the ciliary body, lens, vitreous body, choroid, retina, and a small amount of drugs enter the pigment membrane and vitreous body through the conjunctiva and sclera . There is a barrier between the tissue fluid…
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Overview and Characteristics Of Ophthalmic Nano Drug Delivery System
Most ophthalmic drugs are administered locally in the conjunctival sac, and the most commonly used dosage form is eye drops. Due to various physiological barriers, the eye bioavailability of eye drops is extremely low, generally less than 5%. On the one hand, the main reason is the rapid elimination rate of the drug on the ocular surface and short residence time. Most of the drugs instilled in the eye are lost quickly with the tears (partly absorbed by the conjunctiva and nasal mucosa into the systemic circulation), and partly bound by the contents of the tears or Decomposition; On the other hand, the absorption of the corneal route and the…
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A Few Tips To Better Know About Neutral Lipids
What Are Neutral Lipids? Neutral lipids are defined as hydrophobic molecules lacking charged groups. Neutral lipids, such as cholesteryl ester (CE), triacylglycerol (TAG), and wax ester (WE), provide organisms with inert forms of energy used in conditions of nutrient deprivation and environmental stress. They also provide an excellent “sink” to buffer the toxic effects of fatty acids and fatty alcohols. Elevated cytoplasmic deposition of neutral lipids (primarily CE and TAG) is a significant risk factor for several disease pathologies, including diabetes, obesity, atherosclerosis, and nonalcoholic fatty liver disease (41, 53, 101). For example, the accumulation of CE in smooth muscle cells and macrophages in the vessel wall comprises the earliest recognizable stage…
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What Are Sphingolipids?
Sphingolipids are the most structurally diverse class of membrane lipids, being composed of over 70 long-chain (sphingoid) bases, dozens of amide-linked fatty acids, and more than 300 headgroups. Sphingolipids are present in all eukaryotic and some prokaryotic organisms. 1.What Is The Function Of A Sphingolipid? Sphingolipids are highly bioactive compounds that participate in the regulation of cell growth, differentiation, diverse cell functions, and apoptosis. Sphingolipids are both structural and functional lipids. Their physical properties (such as high phase transition temperatures) affect the properties of membranes and lipoproteins, and they are critical components of the water barrier of skin. Besides, they serve as ligands for extracellular matrix proteins and receptors on…
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Protein Peptide Drug Lung Inhalation Nano Preparation
Pulmonary administration has great advantages as a non-invasive route of administration of protein and peptide drugs. The human respiratory tract has a large surface area, which can avoid the first pass effect of the liver. In addition, the viscosity of the epithelial cell barrier is low, and there is a large amount of potential vasculature, low proteolytic activity and low acidity. Compared with the gastrointestinal tract, there is a thinner mucus layer, so the lungs are suitable for local and systemic administration. However, the mucosa of the respiratory tract is very tight and complex, and it is difficult for macromolecular drugs to penetrate. In fact, a single macromolecule is difficult…
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Chemical Medicine Lung Inhalation Nano Preparation
At present, a variety of chemical drugs are combined with nano-carriers to make lung-inhaled nano-preparations, and have achieved good results, such as anti-tuberculosis drugs, itraconazole, terbutaline sulfate, ciprofloxacin, curcumin and Camptothecin. Anti-tuberculosis drugs Polylactic acid glycolic acid (PLGA) has good biodegradability and biocompatibility, and is widely used as a drug carrier. The pulmonary tuberculosis drugs rifampicin, isoniazid, and pyrazinamide are prepared by the double emulsion/solvent volatilization method to prepare PLGA nanoparticles for pulmonary administration. The particle size is 180-300m, and the encapsulation rate is 50%- 70%. Rifampicin PLGA nanoparticles were prepared by a double emulsion method, and the nanoparticles were dissolved in an alginic acid solution and spray-dried to obtain nano-mixed particles with…
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What Are Monomers?
Monomers are molecules that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. There are mainly four types of monomers, including sugars, amino acids, fatty acids, and nucleotides, and each of these monomer types plays an important role in the existence and development of life, and each can be synthesized through abiotic means. What Are Monomers Made? Polymers are synthetic substances that consist of multiple simpler units called monomers. A polymer is a chain with an indefinite number of monomer units. Homopolymers are polymers made by joining together monomers with the same chemical composition or structure. How Do You Identify Monomer?…
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What Are Block Copolymer Micelles?
Block copolymer micelles are generally formed by the self-assembly of either amphiphilic or oppositely charged copolymers in aqueous medium. The hydrophilic and hydrophobic blocks form the corona and the core of the micelles, respectively. Block copolymer micelles can be classified according to the type of intermolecular forces driving the segregation of the core segment from the aqueous milieu. In the past few decades, at least three main categories were identified, viz. amphiphilic micelles (formed by hydrophobic interactions), polyion complex micelles (PICM; resulting from electrostatic interactions), and micelles stemming from metal complexation. Generally, when the hydrophilic segment is longer than the core block, the shape of the resulting micelles is spherical. Conversely, increasing…
