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Oral Drug Absorption Barrier
Oral drugs enter the gastrointestinal tract by mouth, and then undergo digestion and absorption in the gastrointestinal tract. Studies have shown that the gastrointestinal mucosa is attached to the gastrointestinal tract, which is a key barrier affecting the absorption of oral drugs. Studies have found that the gastrointestinal mucosa is covered with a 100-150gm thick aqueous mucosa layer secreted by goblet cells, which is the rate-limiting step for the drug to reach the surface of intestinal epithelial cells. Below the mucosal layer are columnar epithelial cells with tight junctions. In the cell layer there are intestinal epithelial cells, goblet cells, endocrine cells and Peyer’s cells. The epithelial cell layer faces…
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Oral Nano-drug Delivery System 2
The previous article introduced the relevant information about choosing liposomes and nanoparticles as drug carriers in oral nano-drug delivery systems. This article will continue to introduce the feature of microemulsions, polymers, dendrimers and nano-drug crystals as oral drug carriers. Microemulsion Microemulsion is formed by mixing water phase, oil phase, surfactant and co-surfactant in appropriate proportions, with a particle size of 10~100mpm, transparent or translucent, low viscosity, isotropic thermodynamics and kinetics For a stable oil-water mixing system, there is also literature that the particle size of the microemulsion is 20~200nm. Microemulsions have received extensive attention in recent years because of their significant targeting, sustained-release effects and strong solubilization effects on poorly soluble…
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Oral Nano-drug Delivery System 1
With the development of new drug discovery related technologies such as high-throughput screening technology, a large number of drug candidates have been discovered, but their solubility is often low. 40% to 70% of drug candidates are difficult to obtain therapeutic concentrationdue to low solubility and poor oral absorption. In particular, protein and peptide drugs have large molecular weights, are not easy to penetrate biological membranes, are susceptible to the action of enzymes in the organism, and their oral bioavailability is very low. According to the solubility and membrane permeability of the drug, drugs can be divided into 4 categories, namely the Biopharmaceutical Classification System (BCS): Class I is high solubility and high permeability…
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Injection Nano Drug Delivery System II
As mentioned above, liposomes, microemulsions and nanoemulsions are used for pharmaceutical transportation through the injection of nanometer drug delivery system. And this article will further introduce other nano-carriers that can be administered by injection nano-administration, including: nanoparticles, polymer micelles, nanogels, polymer complexes, and nanosuspensions. Nanoparticles Nanoparticles, as a carrier for the injection of nano-drug delivery systems, have their advantages mainly in: 1. The more hydrophilic the surface of the surface-modified nanoparticles, the smaller the uptake by macrophages. 2. The in vitro release of drugs can be adjusted by controlling the increase in PEG molecular weight and content or the decrease in copolymer molecular weight. 3. The distribution of nanoparticles in…
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Injection Nano Drug Delivery System 1
Injection administration is to inject drugs into the body through injection to achieve the purpose of preventing and treating diseases. There are three ways of injection administration: intravenous (IV), intramuscular (IM) and subcutaneous (SC). Each has its own advantages and disadvantages. Different injection methods should be selected according to the specific situation. Liposomes Liposomes are vesicles sealed by a bilayer of phospholipids, similar to the cell structure, with an internal aqueous phase that can encapsulate water-soluble drugs. The inside of the lipid bilayer is fat-soluble and can encapsulate fat-soluble drugs, but the capacity is limited. According to the particle size, liposomes can be divided into small unilamellar vesicles (SUV, 30~100nm),…
