What is PEG

Poly(ethylene glycol)(PEG), also known as poly(ethylene oxide)(PEO), is an amphiphilic polyether that is soluble both in water and most organic solvents. PEG and its derivatives are among the few polymers approved for medical uses by the U.S. Food and Drug Administration (FDA).

Functionalized PEG, also named active PEG, activated PEG or functional PEG, is a family of PEG derivatives decorated with functional groups. Functionalized PEGs are used broadly for drug pegylation (conjugation of PEG molecule to drug molecules), polymer engineering, nanotechnology, biotechnology, and biomedical engineering.

PEG is the basis of a number of laxatives (e.g., macrogol-containing products, such as Movicol and polyethylene glycol 3350, or SoftLax, MiraLAX,ClearLAX, Osmolax or GlycoLax). Whole bowel irrigation with polyethylene glycol and added electrolytes is used for bowel preparation before surgery or colonoscopy.  In the United States, MiraLAX and Dulcolax Balance are sold without prescription for short-term relief of chronic constipation. Therapeutic classification is as an Osmotic Laxative that works by drawing water into the lumen of the intestinal tract. Shown to decrease consistency and increase weight of stool in constipated patients at low doses.

Miralax is currently FDA approved for adults for a period of seven days, and is not approved for children.[7] A 2007 comparison showed that patients suffering from constipation had a better response to PEG medications than to tegaserod.These medications soften the fecal mass by osmotically drawing water into the GI tract. It is generally well tolerated; however, possible side effects are bloating, nausea, gas, and diarrhea (with excessive use).

When attached to various protein medications, polyethylene glycol allows a slowed clearance of the carried protein from the blood. This makes for a longer-acting medicinal effect and reduces toxicity, and it allows longer dosing intervals. Examples include PEG-interferon alpha, which is used to treat hepatitis C, and PEGfilgrastim (Neulasta), which is used to treat neutropenia. It has been shown that polyethylene glycol can improve healing of spinal injuries in dogs. Polyethylene glycol is also commonly used to fuse B-cells with myeloma cells in monoclonal antibody production.

PEG is used as an excipient in many pharmaceutical products. Lower-molecular-weight variants are used as solvents in oral liquids and soft capsules, whereas solid variants are used as ointment bases, tablet binders, film coatings, and lubricants. PEG is also used in lubricating eye drops.

  • PEG, when labeled with a near-infrared fluorophore, has been used in preclinical work as a vascular agent, lymphatic agent, and general tumor-imaging agent by exploiting the Enhanced permeability and retention effect (EPR) of tumors.
  • High-molecular-weight PEG (e.g., PEG 8000) has been shown to be a dietary preventive agent against colorectal cancer in animal models.
  • The Chemoprevention Database shows PEG is the most effective known agent for the suppression of chemical carcinogenesis in rats. Cancer prevention applications in humans, however, have not yet been tested in clinical trials.
  • The injection of PEG 2000 into the bloodstream of guinea pigs after spinal cord injury leads to rapid recovery through molecular repair of nerve membranes. The effectiveness of this treatment to prevent paraplegia in humans after an accident is not known yet.
  • PEG is being used in the repair of motor neurons damaged in crush or laceration incidents in vivo and in vitro. When coupled with melatonin, 75% of damaged sciatic nerves were rendered viable.
  • PEG is proposed as the ‘glue’ to reconnect the spinal cord in the world’s first head transplant operation.

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