H2 histamine receptor antagonist, anti-ulcer agent
Polyethylene glycol is a polymer which is hydrolyzed by ethylene oxide. It has no toxicity and irritation. It is widely used in various pharmaceutical preparations. The toxicity of low molecular weight polyethylene glycol is relatively large. In general, the toxicity of diols is very low. Topical application of polyethylene glycol, especially mucosal drug, can cause irritant pain. In topical lotion, this product can increase the flexibility of the skin, and has a similar moisturizing effect with glycerin. Diarrhoea can occur in large doses of oral administration. In injection, the maximum polyethylene glycol 300 concentration is about 30% (V/V). Hemolysis could occur when the concentration is more than 40% (V/V).
Poly(ethylene glycol) is combustible.
Used in conjunction with carbon black to form a conductive composite.1 Polymer nanospheres of poly(ethylene glycol) were used for drug delivery.2
Poly(ethylene glycol) is heat-stable and inert to many chemical agents; Poly(ethylene glycol) will not hydrolyze or deteriorate under normal conditions. Poly(ethylene glycol) has a solvent action on some plastics.
A polymer used to precipitate proteins, viruses, DNA and RNA
Application in biomedicine
Polyethylene glycol is also known as polyoxirane (PEO). It is a linear polyether obtained by ring opening polymerization of ethylene oxide. The main uses in the field of biomedicine are as follows:
- Contact lens liquid. The viscosity of polyethylene glycol solution is sensitive to the shear rate and it is not easy for bacteria to grow on polyethylene glycol.
- Synthetic lubricants. The condensation polymer of ethylene oxide and water. It is a cream matrix for preparing water-soluble drugs. It can also be used as a solvent for acetylsalicylic acid and caffeine, which is difficult to dissolve in water.
- Drug sustained-release and immobilized enzyme carrier. The polyethylene glycol solution is applied to the outer layer of the pill to control the diffusion of drugs in the pill so as to improve the efficacy.
- Surface modification of medical polymer materials. The biocompatibility of medical polymer materials in contact with blood can be improved by adsorption, interception and grafting of two amphiphilic copolymers containing polyethylene glycol on the surface of medical polymers.
- It can make the membrane of the alkanol contraceptive pill.
- It can make hydrophilic anticoagulant polyurethane.
- Polyethylene glycol 4000 is an osmotic laxative. It can increase osmotic pressure and absorb moisture in the intestinal cavity, which makes the stool soften and increase in volume, resulting in bowel movement and defecation.
- Denture fixing agent. Peg nontoxic and gelatinous nature can be used as a component of denture fixer.
- PEG 4000 and PEG 6000 are commonly used to promote cell fusion or protoplast fusion and help organisms (such as yeasts) to take DNA in transformation. PEG absorbs water from the solution, so it is also used to concentrate the solution.
Atpeg 4000 (ICI Americas).
Poly(ethylene Glycol) molecules of approximately 2000 monomers. Poly(ethylene Glycol) is used in various applications from industrial chemistry to biological chemistry. Recent research has shown PEG m
aintains the ability to aid the spinal cord injury recovery process, helping the nerve impulse conduction process in animals. In rats, it has been shown to aid in the repair of severed sciatic axons,
helping with nerve damage recovery. It is industrially produced as a lubricating substance for various surfaces to reduce friction. PEG is also used in the preparation of vesicle transport systems in
with application towards diagnostic procedures or drug delivery methods.
Clear colorless viscous liquid.
White waxy crystalline flakes
PEG is available commercially as a powder or as a solution in various degrees of polymerization depending on the average molecular weight, e.g. PEG 400 and PEG 800 have average molecular weights of 400 and 800, respectively. They may be contaminated with aldehydes and peroxides. Solutions deteriorate in the presence of air due to the formation of these contaminants. Methods available for purification are as follows: Procedure A: A 40% aqueous solution of PEG 400 (2L, average molecular weight 400) is de-aerated under vacuum and made 10mM in sodium thiosulfate. After standing for 1hour at 25o, the solution is passed through a column (2.5x20cm) of mixed-bed R-208 resin which has a 5cm layer of Dowex 50-H+ at the bottom of the column. The column was previously flushed with 30% aqueous MeOH, then thoroughly with H2O. A flow rate of 1mL/minute is maintained by adjusting the fluid head. The first 200mL are discarded, and the effluent is then collected at an increased flow rate. The concentration of PEG solution is checked by density measurement, and it is stored (preferably anaerobically) at 15o. Procedure B: A solution of PEG 800 (500g in 805mL H2O) is made 1mM in H2SO4 and stirred overnight at 25o with 10g of treated Dowex 50-H+ (8% crosslinked, 20-50 mesh). The resin, after settling, is filtered off on a sintered glass funnel. The filtrate is treated at 25o with 1.5g of NaBH4 (added over a period of 1minute) in a beaker with tight but removable lid through which a propeller-type mechanical stirrer is inserted and continuously flushed with N2. After 15minutes, 15g of fresh Dowex 50-H+ are added, and the rate of stirring is adjusted to maintain the resin suspended. The addition of an equal quantity of Dowex 50-H+ is repeated and the reaction times are 30 and 40minutes. The pH of a 1 to 10 dilution of the reaction mixture should remain above pH 8 throughout. If it does not, more NaBH4 is added or the addition of Dowex 50-H+ is curtailed. (Some samples of PEG can be sufficiently acidic, at least after the hydrolysis treatment, to produce a pH that is too low for efficient reduction when the above ratio of NaBH4 to Dowex 50-H+ is used.) About 30minutes after the last addition of NaBH4, small amounts of Dowex 50-H+ (~0.2g) are added at 15minute intervals until the pH of a 1 to 10 dilution of the solution is less than 8. After stirring for an additional 15minutes the resin is allowed to settle, and the solution is transferred to a vacuum flask for brief de-gassing under a vacuum. The de-gassed solution is passed through a column of mixed-bed resin as in procedure A. The final PEG concentration would be about 40% w/v. Assays for aldehydes by the purpural method and of peroxides are given in the reference below. Treatment of Dowex 50-H+ (8% crosslinked, 20-50 mesh): The Dowex (500g) is suspended in excess 2N NaOH, and 3mL of liquid Br2 is stirred into the solution. After the Br2 has dissolved, the treatment is repeated twice, and then the resin is washed with 1N NaOH on a sintered glass funnel until the filtrate is colourless. The resin is then converted to the acid form (with dilute HCl, H2SO4 or AcOH as required) and washed thoroughly with H2O and sucked dry on the funnel. The treated resin can be converted to the Na salt and stored. [Ray & Purathingal Anal Biochem 146 307 1985.]
Air & Water Reactions