Poly(lactic-co-glycolic acid) (PLGA) is a functional polymer organic compound randomly polymerized by lactic acid (PLA) and glycolic acid (PGA). It has been approved by the U.S. Food and Drug Administration It is certified by the Food and Drug Administration (FDA) and is a copolymer material available on the market. PLGA has good biocompatibility, biodegradability, mechanical strength, good plasticity, surface modification, and drug encapsulation. It has a wide range of uses in the field of biomedical engineering and has been used in drug sustained-release carriers, artificial catheters and tissue engineering scaffold materials. As a drug carrier, PLGA is soluble in common solvents such as acetone and ethyl acetate. The size, shape…

As a promising systemic drug delivery method, transdermal drug delivery system (TDDS) is easier and more convenient to operate than traditional oral, intravenous and subcutaneous injection methods. It can improve patient compliance while also avoiding First-pass effect and drug side effects. As the largest organ of the human body, the skin is also the body’s first line of defense against foreign microorganisms and chemical substances. Its drug permeability is lower, which is orders of magnitude different compared to the epithelial cells of the gastrointestinal tract and lungs. Therefore, how to pass through the many barriers of human skin is the first problem faced during transdermal drug delivery. In the past…

Micro needle (MN) is a micro needle-shaped structure, the length of 100 ~ 1000μm, the bottom diameter of several hundred micrometers, the tip diameter is less than a few dozen micrometer, usually in the form of micro- needle array sticker, can penetrate the skin surface cortex to form micro-porous tubes, without touching the nerve endings within the cortex causing pain. At present, researchers generally use silicon, metal, polymers and other materials to prepare micro needles through traditional microelectronic mechanical systems (MEMS) processes and new processing technologies. Depending on the way of action, the micro needle can be divided into solid, coated, empty, soluble and hydrogel micro needles, widely used in…

The existing pulmonary inhalation nano drug delivery system dosage forms are mainly divided into two types: liposomes and nanoparticles. Liposomes Among the various dosage forms for pulmonary administration, liposomes have obvious advantages, such as being suitable for encapsulating lipophilic drugs, avoiding local irritation, enhancing curative effects, reducing toxic and side effects, and evenly distributing active drugs in the lungs. Lung-administered liposomes can also be used for gene therapy. Compared with viral vectors, liposomes are simple to prepare, have no damage to normal tissues, and have high safety. Liposome pulmonary drug delivery has the following characteristics: 1. The main component of alveoli is lipids, among which phospholipids account for 80% of…

In the clinical transdermal drug delivery process, there are many factors that affect the transdermal absorption of the drug, mainly including: skin hydration, skin temperature, skin conditions, and skin locations. Skin Hydration The phenomenon that the water content of the skin exceeds the normal state is called skin hydration. After the skin is saturated with water, the tissue softens, swells, wrinkles disappear, and the permeability increases significantly. Skin hydration promotes transdermal absorption of drugs. The encapsulation method or the application of ointment on the skin reduces the evaporation of skin moisture, and the covering effect increases the endogenous hydration of the stratum corneum and increases skin penetration. The hydration of the stratum corneum can…

Transdermal drug delivery systems in a broad sense include topical drug delivery systems and transdermal drug delivery systems (TDDS). The former acts on the skin or subcutaneous tissue; the latter is the absorption of drugs into the blood through the skin. Compared with oral or injection administration, the advantages of the transdermal drug delivery system include: 1. No gastrointestinal irritation; 2. Avoid the first pass effect of the liver 3. Get a controlled release effect; 4. Easy to use, good patient compliance; 5. High safety , Easy to remove; 6. less skin tissue degrading enzymes, can be used for the administration of macromolecular drugs. Global sales of transdermal drug delivery preparations reached US$12.7 billion in 2005, US$21.5 billion in…

Oral absorption of nanomedicine means that nanomedicine enters the blood circulation through the gastrointestinal tract. Nanomedicine has a very complicated process after entering the body, interacting with the components in the biological system (such as proteins and cells), and has unique distribution, clearance, metabolism and immune response behaviors in the body. There are three main ways for nanoparticles to be absorbed in the gastrointestinal tract: 1. Cell bypass channel transport; 2. Transcellular uptake by intestinal epithelial cells; 3. Phagocytosis by microfold cells (M cells) in Peyer’s patches in the ileum. Absorption through M cells is the main absorption route of oral nanoparticles. When the nanoparticles enter the gastrointestinal tract, part…