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Liposomes as Carriers of Antitumor Drug
In recent years, the incidence of tumors has become higher and the tumor patients seem to be younger, which has seriously affected people’s health and quality of life. According to statistics, the number of newly diagnosed cancer patients in the world in 2007 has reached 12 million, and as many as 7 million people die from cancer worldwide each year. The current effective method is chemotherapy. Compared with normal tissues, tumor tissue has increased vascular endothelial cell space, thin blood vessel walls, and increased vascular permeability, and it also lacks of lymphatic vessels in tumor tissue, which reduces the discharge of metabolites. Normal tissues have small capillary endothelial membrane pores.…
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In Vivo Characteristics of Antitumor Drug Liposomes
Anti-tumor drug liposomes need to be studied in vivo during the development process, which includes examination of liposome pharmacokinetics, clinical efficacy and in vivo safety. Pharmacokinetics Liposomes have a greater influence on the pharmacokinetic parameters of drug-loaded drugs, which are characterized by increased AUC(area under the curve, it shows drug’s bioavailabilit), extended half-life period, decreased clearance, decreased volume of distribution, and changes in tissue distribution. The pharmacological changes can be explained and proven from the anatomical characteristics of tumor sites, structural characteristics of liposomes, non-clinical studies and clinical studies. The targeting of liposomes is divided into passive targeting, physicochemical targeting and active targeting. These targeting effects make the pharmacokinetic behavior of liposome…
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The Basic Composition of Liposomes-Cholesterol, Antioxidants and Surfactants
In addition to phospholipids, the basic composition of liposomes includes cholesterol, antioxidants and surfactants. Cholesterol Cholesterol (Chol) is a commonly used lipid for preparing liposomes, which can increase the rigidity of the lipid membrane and the stability of the liposome. Cholesterol is an amphiphilic molecule with a hydroxyl polar head, and the hydrophobic part is composed of four rigid steric rings in a planar configuration connected by a flexible short hydrocarbon chain. The structure of soy sterol is similar to that of cholesterol, and it can also be used for the construction of liposomes, and its membrane stability function is also similar to that of cholesterol. The liposome bilayer is…
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Liposome Preparation Method 1
Phospholipids are generally white or light yellow powders or lumps at room temperature. They are very soluble in chloroform and can also be dissolved in ether, n-hexane or ethanol, and are almost insoluble in water or acetone. Disperse the phospholipid molecules into the aqueous solution by hydration treatment after high dispersion, or changing the solvent. When the concentration reaches the critical micelle concentration (CMC), self-assembly occurs through the hydrophobic interaction to form a bilayer structured liposome bubble. Commonly used preparation methods of liposomes in the laboratory include thin film method, reverse evaporation method, double emulsion method, centrifugal method, injection method, calcium fusion method, ammonium sulfate gradient method, etc. In order to ensure the final smooth transition to…
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Phospholipids—the Basic Composition of Liposomes
Phospholipids are the basic materials composing liposomes, which also determine the liposome’s physical and chemical properties. Factors affecting the stability of liposome formulations include the phase transition temperature and electric charges associated with phospholipids, the particle size associated with the manufacturing process, and the temperature, pH, and ionic strength associated with the environment. The type and amount of phospholipids are essential for the preparation of liposomes. Classification of Phospholipids Phospholipids are divided into phosphoglycerides and sphingomyelins by structure. Glycerol phosphate (PG) is composed of a hydrophilic polar head and two hydrophobic tails. The 1st and 2nd hydroxyl groups on the glycerol skeleton are esterified with fatty acids, and the 3rd…
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Application of Liposome as Drug Carrier
Liposomes are bilayer vesicles composed of phospholipids as the main material, and were first discovered by Bangham, a British scientist. Liposome’s structure is similar to biofilm, also known as artificial biofilm, and is widely used to study the structure and function of biofilm. Liposome used as a drug carrier began in the early 1970s. Due to the advantages of biocompatibility, biodegradability, non-toxicity and non-immunogenicity, liposomes have rapidly developed as new drug dosage forms. After more than 40 years of research, there are currently 12 liposomal preparations on the market. The drugs involved include adriamycin hydrochloride, amphotericin, muramyl-tripeptide, paclitaxel, gentamicin, and cytosine arabinoside, etc. In addition, various types of liposomes are…
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Nanocarrier System Targeting Stromal Organelles
With the development of biomedicine, some diseases are clinically found to be caused by organelle lesions. And the drugs used to treat these diseases not only need to cross the cell membrane to enter the cell, but also need to target specific organelles to play a role. Therefore, in the development of drugs for these diseases, suitable carriers are needed to help the drugs target the target organelles. With the development of nanotechnology, researchers have found that nanosystems have obvious advantages in the field of organelle targeting. Therefore, more and more nanoparticles are used to target the endoplasmic reticulum, lysosomes and mitochondria. Mitochondrial Targeting Mitochondria play a very important role…
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Application Prospects of Targeted Nano Drug Delivery System
Targeted drugs were proposed by German scientist and Nobel Prize winner Ehrlich in 1906 and have a history of more than 100 years. Until the late 1970s, with the advancement of molecular biology, cell biology, and materials science, targeted formulations developed rapidly, and products began to be marketed. The nano drug delivery system is distributed in specific organs, tissues, cells, and even intracellular structures in the body through passive targeting, active targeting, physical and chemical targeting, etc., and changes the distribution of prototype drugs in vivo. With the leapfrog development of life sciences, human understanding of disease pathogenesis and drug action mechanisms has transitioned from a macroscopic overall level to…
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Nuclear Targeted Nano Drug Carrier
The nucleus is the place where the genetic material in the cell is stored, copied and transcribed, and plays an important role in the metabolism, growth and differentiation of the cell. Therefore, the nucleus is also the site of action for various drugs such as DNA, intercalators, alkylating agents, and topoisomerase inhibitors. The nuclear membrane is composed of two layers of membranes on which nuclear pore complexes (NPCS) exist. The nuclear membrane will disappear only when the cell undergoes mitosis. In other cases, the only way for large molecules to enter the nucleus is the nuclear pore complex, which allows particles with a diameter of 9 nm or molecules with a…
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Cytoplasm Targeted Nano Drug Carrier
The cytoplasm is the general term for all translucent, colloidal, granular materials except the nuclear area surrounded by the cytoplasmic membrane, and is composed of the cytoplasmic matrix, endomembrane system, cytoskeleton, and inclusions. Among them, the cytoplasmic matrix, also known as cytosol, is a homogeneous and translucent colloid in the cytoplasm, which is filled between other tangible structures; its main function is to provide an ionic environment for various organelles to maintain their normal structure and supply all substrates for various organelles to complete functional activities, and is also the venue for certain biochemical activities. The importance of cytoplasmic matrix transport is not only due to the existence of multiple drug targets in the matrix…
