Question 100 on the preparation of liposomes

See if the temperature on the data is not much different from the temperature of your century.

Film dispersion, injection, reverse.

Currently, the brigade is being preparedLiposomesThere are many methods, commonly used are thin film method, reversed-phase evaporation method, solvent injection method and re-emulsion method, etc., these methods are generally called passive drug loading method, and HGradient methodThe ammonium sulfate gradient method is generally referred to as the active drug loading method.

Liposomes are made up of phospholipids.

Molecules are formed by hydrophobic interaction in the aqueous phase, so the emphasis in the preparation of liposomes is not membrane assembly, but how to form vesicles of appropriate size, high encapsulation efficiency and high stability.

Depending on the preparation method, the particle size of liposomes can range from tens of nanometers to several microns, and the structure is also different.

The common preparation methods for liposomes are mainly thin film dispersion, reversed-phase evaporation, injection, ultrasonic dispersion, etc.

In the preparation of drug-containing liposomes, the drug is first dissolved in the aqueous phase or organic phase, and then the drug-containing liposomes are prepared according to the appropriate method, which is suitable for drugs with strong lipid-soluble, and the obtained liposomes have a high encapsulation efficiency.

1. Injection method. It is mainly used for the preparation of single-chambered liposomes, and a few are multi-chamber lead liposomes, and most of their particle sizes are below 2 meters.

2. Film dispersion method. It is mainly used for the preparation of multi-chamber or large single-chamber liposomes, and single-chamber liposomes are the main ones after ultrasound.

3. Ultrasonic dispersion method. It is mainly used for the preparation of single-chamber liposomes.

4. Reverse phase evaporation method. The phospholipids are dissolved in organic solvents, a buffer containing drugs is added, ultrasonic is made into a stable emulsion, the organic solvent is removed under reduced pressure to form a thin film on the wall of the rotator, and the buffer is added to make the gel fall off, and the aqueous suspension of Huiji is prepared, and the unencapsulated drug is removed by gel chromatography or ultracentrifugation, that is, a large single-chamber liposome is obtained.

Answer]: The preparation method of B lipid digging is very judgmental, and the injection method is commonly used; thin film dispersion method; ultrasonic dispersion method; reverse phase evaporation method; Freeze-drying.

Answer]: The preparation methods of liposomes include: injection method, thin film dispersion and dispersion method, reverse phase evaporation method, freeze-drying method and ultrasonic dispersion method.

The saturated aqueous solution method is the preparation method of the inclusion complex. The single coagulation method and the complex condensation leakage method are the preparation methods of microcapsules.

The preparation method of liposomes does not include the radiation cross-linking method. Mausoleum

There are many methods for the preparation of liposomes, and the commonly used ones are: injection method; thin film dispersion method; ultrasonic dispersion method; reverse phase evaporation method; Freeze-drying.

The quality evaluation methods include: morphology, particle size and distribution; encapsulation efficiency and drug loading; leakage rate; Distribution of the drug in vivo. Factors influencing the encapsulation rate of drugs in liposomes:

It mainly includes the feeding ratio of lipid-like membrane materials; the charge of liposomes; Liposome particle size; solubility of the drug and preparation container, etc.

Liposomes are liposomes (hollow) prepared from lecithin and ceramides, etc., with the same bilayer structure as the cell membrane structure, and have excellent moisturizing effect, especially the liposomes coated with moisturizing substances such as hyaluronic acid and polyglucoside.

Classification of liposomes:

1.Liposomes are divided into single-compartment liposomes and multi-compartment liposomes according to the number of layers of lipid-like bilayers they contain.

Small unicompartmental liposomes (SUVs): approximate particle size; Large unicompartmental liposomes (LUVs) are large vesicles in a single layer with a particle size. The vesicles of the multilayered bilayer are called multi-compartmented liposomes (MIVs) and have a particle size between 1 5 m.

2.According to the structure: single-compartment liposomes, multi-compartment liposomes, polycystic liposomes.

3.According to the charge: neutral liposomes, negatively charged liposomes, positively charged liposomes.

4.According to the sexual ruler, filial piety can be divided into: general liposomes, special liposomes.

The preparation and characterization of liposomes is an important research direction in nanomedicine. Liposomes are nanoscale spherical structures formed by the self-assembly of one or more lipid-like molecules, which can be used for the preparation and delivery of drugs, and have attracted much attention because of their good biocompatibility, low toxicity and modulation. The preparation and characterization of liposomes involves research in multiple disciplines, including chemistry, biology, physics, etc.

When preparing liposomes, it is necessary to consider the selection, proportion, mixing and preparation conditions (e.g., temperature, pH, etc.) of different lipid molecules to achieve the desired drug encapsulation effect and stability. The characterization of liposomes requires the help of various analytical techniques, including dynamic light scattering, transmission electron microscopy, ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, etc., to obtain information such as particle size, distribution, morphology, stability, drug load and release of liposomes. The study of the preparation and characterization of liposomes can provide basic and applied technical support for the optimization and development of liposomes in biomedical applications.

For example, by adjusting the composition and preparation parameters of liposomes, Weistool can effectively regulate its metabolism and drug release behavior in vivo, improve the best effect and alleviate adverse reactions; At the same time, quantitatively understanding the structure and properties of liposomes can also help overcome some common problems in nanomedicine research, such as stability, biodistribution, toxicity, etc.

Answer]: 1. Characteristics of liposomes:

Targeting and lymphatic orientation: passive targeting of the reticuloendothelial system of the liver and spleen. It is used for the prevention and treatment of monocyte-macrophage system diseases such as liver parasitic disease and leishmaniasis.

For example, the hepatic leishmania drug meglumine liposome antimonate has a 200 700 times higher concentration in the liver than that of ordinary preparations. Sustained-release effect: Slow release, retarding renal excretion and metabolism, thereby prolonging the duration of action.

Reduces drug toxicity: liposomes such as amphotericin B can reduce cardiotoxicity.

Improve stability: such as insulin, liposomes, vaccines, etc., can improve the stability of the main drug.

Second, the existing problems are:

For liposomes, due to the passive targeting effect (easy to be engulfed by the reticuloendothelial system), the tissue distribution and pharmacokinetic behavior of the product are usually changed compared with ordinary preparations.

Answer]: The preparation methods of e-liposomes generally include thin film dispersion base Sun method, reverse phase evaporation method, freeze-drying method, injection method and ultrasonic Chunfeng coarse dispersion method, and non-choke town includes co-precipitation method.