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Quality Control Of Liposomes 2
As a promising drug carrier, liposomes require strict quality control for clinical use. In the previous article, we have introduced the requirements and methods of liposome morphology and particle size control. This article will introduce other parameters involved in liposomes as drug carriers,including: encapsulation rate, oxidation index, lysophospholipid, drug content, leakage rate, osmotic pressure and sterilization conditions. Encapsulation Efficiency Encapsulation efficiency is an important indicator to measure the quality of liposomes. It refers to the ratio of the encapsulated drug to the total amount of drug in the liposome suspension. The key to determining the encapsulation efficiency is to separate the unencapsulated free drug from the liposome suspension without destroying the…
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What Is The Antiviral Drug Liposome?
Viruses are the smallest kind of pathogenic microorganisms. They reproduce in cells. The core is ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), and the outer shell is protein, which does not have a cell structure. The virus parasitizes in the host cell and relies on the host cell metabolic system for proliferation and replication. Statistics show that about 60% of epidemics are caused by viral infections. The research and development of antiviral drugs has naturally become a hot spot for investment in the pharmaceutical industry. Until now, there is still a lack of specific drugs for the treatment of viral diseases. The clinically commonly used drugs mainly include the following…
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Quality Control Of Liposomes 1
As a drug carrier, liposome not only improves the in vivo behavior of the drug, improves the therapeutic index of the drug, reduces the toxicity of the drug, and reduces the adverse reactions of the drug, and has a certain slow-release and controlled-release effect, reduces the dose or frequency of drug administration, and improves patient compliance . According to the characteristics of liposome formulations, the stability of liposomes has always been a concern of researchers. Liposomes are easy to aggregate, drugs are easy to leak (decrease in encapsulation rate) and oxidative deterioration will directly affect the safety and effectiveness of liposome drugs, so the quality of liposome drugs should be studied and…
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Liposome Preparation Method 2
Liposomes have attracted researchers’ attention because of their unique properties. Its successful application as a drug delivery carrier makes it a key research object in the field of drug delivery. There are already many methods for the preparation of liposomes, the above has introduced thin film method, reverse evaporation method, re-emulsion method and centrifugation method. Immediately above, this article focuses on the injection method, calcium fusion method, ammonium sulfate gradient method, and high-pressure homogenization. Injection Method Dissolve lipids in water-miscible or immiscible organic solvents, inject into the aqueous phase with a micro syringe at an appropriate rate, and remove organic solvents by ultrafiltration, dialysis, reverse osmosis, reduced-pressure evaporation, etc. as needed.…
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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…