PEG and Extended Half-Life
PEG stands for polyethylene glycol. This is a substance that has many uses, especially in medicine. Before we talk too much about PEG, however, let's first discuss “half-life.” This is an important idea to understand when it comes to talking about how long a medication remains in your body after you take it. The half-life is the time it takes for half of the dose of a medicine to be removed from your body by your liver or your kidneys. These organs act as filters that eliminate substances from the bloodstream. For example, if a medication you are prescribed has a half-life of 5 hours, that means half of the medication will have been removed from your body after a 5-hour period.
How PEGylation Extends the Half-Life of a Medicine
So what does all of this have to do with PEG? PEG is sometimes attached to a drug molecule in a process called PEGylation. This is done to make it harder for your body to remove the medication. After PEGylation, each individual molecule of a drug is larger and more difficult to filter through the kidneys. Think about how hard it would be for you to walk through a narrow doorway while carrying someone on your shoulders. PEGylation works much the same way to keep the medication circulating longer in your bloodstream.
PEGylation slows the removal of the drug from the body
PEG may help in other ways, too. For instance, sometimes your immune system will target drug molecules and remove them from your system. PEG, when attached to a drug molecule, can also help to “hide” the drug from your immune system so it remains in your body longer. And this means you may get a longer, or extended, half-life.
An Extended Half-Life Means a Drug Remains Longer in Your Body
As you can see, half-life is important when thinking about infused factor. If you have a bleeding disorder, you want the factor to circulate as long as possible in your bloodstream, so it’s ready to become activated if you have a bleed.
PEGylation in Brief:
- PEGylation is a well-established technology: PEGylated pharmaceutical products have been available since 1990 and continue to be developed
- PEGylation is also used in over-the-counter medicines
- PEGylation helps extend the half-life of a medicine so it will stay in your body longer