A Brief Guide on Polyethylene Glycol (PEG)

One of the most frequently asked questions we get at Troscriptions is why we use Polyethylene Glycol (PEG, for short) as the base/suspension media for our formulas. 

There are a lot of very smart people who use our products (who are even smarter after they use our products!) so today, TroNation, let’s lay it all out on the table and allay your concern(s). After all, knowledge is (blue and orange) power. 

But! Before we dive deep, there are three things to say right from the get-go:    

First,do not confuse polyethylene glycol with propylene glycol. The former is quite safe and a long-established FDA-approved drug delivery method used around the world, especially by compounding pharmacists (more on all of this later).  The latter is antifreeze and will kill you if you drink it…so please don’t do that!  

Second and third, our formulations using polyethylene glycol are bothnon-absorbable andvery low dose, meaning that it does not get absorbed into your body and it will not cause GI distress or any of those other symptoms/issues that you may have heard about.  

But still…is polyethylene glycol really safe? And why did we decide to use it in our products? Read on to learn more! 

What Exactly is Polyethylene Glycol?

Polyethylene Glycol is also known as polyethylene oxide (PEO) or polyoxyethylene (POE) depending on its weight. These three names all refer to the same molecule, but PEG is preferred in the biomedical field, while PEO is preferred in the chemistry field. 

The wide variety of polyethylene glycols available are made via the polymerization of ethylene oxide and most are in either liquid/low melting solid form. Even though the physical properties and applications are different, the chemical properties remain virtually the same. These varying physical properties are attributed to the different polyethylene glycol molecular weights and chain length effects[5].

Polyethylene Glycol History

Polyethylene glycol was first discovered in 1859 when A.V. Laurenco heated ethylene glycol and 1,2-dibromoethane and isolated oligo(ethylene glycol)s by fractional distillation[1]. In 1953, Sperber et al used PEG 4000 as a marker to trace the flow of water and solutes in sheep. This established PEG as a reliable marker in scientific investigation because of its chemical purity, non-absorbability, lack of toxicity, resistance to enzymes, and because it was very easy to accurately measure[1]

PEG found other uses as well, especially in the field of Gastroenterology due to its solubility, unique osmotic properties, stability, strength, and because it stays in the intestinal lumen (i.e. is not systemically absorbed). Since the 1970s, high doses of polyethylene glycol (>16 grams) have been used as a laxative and for colonoscopy preparation[1]

PEG also found use in the cosmetic industry. Since many types of PEG are hydrophilic (water loving), they are used as penetration enhancers for many topical products such as surfactants, cleansing agents, emulsifiers, skin conditioners, and humectants[2]

In pharmaceuticals, PEG is used as an inactive base/suspension of choice in several types of formulations including as a solvent, surfactant, ointments, and tablets/lozenges.  In the mouth (and as a troche), PEG is ideal due to its slow dissolution rate (15 to 30 minutes) and water solubility. As a result, it is the gold standard base used to make troches by compounding pharmacists worldwide. 

Another use for PEG is to attach it to different molecules, drugs, or proteins in a process called PEGylation[3]. This is achieved by covalently coupling a PEG to a larger molecule. Once the molecule has the PEG attached to it, it is classified as a PEGylated molecule. The benefits of this process include improved solubility, increased size of molecule, the “masking” of a protein from the immune system, etc. PEGylation of therapeutic proteins has resulted in the improved treatment of diseases such as hepatitis C, leukemia, rheumatoid arthritis, Crohn’s disease, and more[3]

PEG Safety

PEG is a Generally Regarded as Safe (GRASS) ingredient that is approved by the FDA for use in a wide range of industries with very few safety concerns, especially when used orally and at low doses.  

Common side effects at high doses include flatulence, nausea, stomach cramps, diarrhea, and a swollen abdomen[4]. Toxicity is very rare. These side effects only occur at high doses used in IV infusions containing PEG or massive ingestion of oral PEG 

Contraindications include: 

  • Suspected bowel obstruction
  • Appendicitis 
  • Inflammatory Bowel Disease
  • Perforated bowel 
  • Hypersensitivity to PEG 

How We Use Polyethylene Glycol at Troscriptions 

As mentioned earlier, PEG is the gold standard for troche production by compounding pharmacists worldwide and is extremely safe when used at low doses. And Dr. Ted, along with the 3 other practicing physicians on the Troscriptions team, have been using buccal troches with polyethylene glycol as a base for decades collectively.  

During early troche R&D in 2019 (prior to launch in 2020), the team did try several potential bases but these alternatives either melted too slowly, too fast, inactivated the troche ingredients, or weren’t heat stable.  

So the team decided to use the safest pharmaceutical grade PEG (1450) on the market, at a low dose of < 500mg per troche. This dose, for reference, is 32X lower than a potential laxative dose (16 grams or greater). 

And in addition, after extensive testing using PEG 1450, we found that it was the best base available to deliver our delicate ingredients to the buccal mucosa in pristine and precise condition, have them absorb over 15 to 30 minutes, and let them bypass first metabolism making them more bioavailable (and with a more rapid onset of action) compared to a tablet or capsule.   

Sounds awesome, right? Because our buccal troches are and low dose PEG is safe, tried and true, FDA approved, orange + blue.    

References

  1. Fordtran, J. S., & Hofmann, A. F. (2017). Seventy Years of Polyethylene Glycols in Gastroenterology: The Journey of PEG 4000 and 3350 From Nonabsorbable Marker to Colonoscopy Preparation to Osmotic Laxative.Gastroenterology,152(4), 675–680.https://doi.org/10.1053/j.gastro.2017.01.027 
  2. Jang, H. J., Shin, C. Y., & Kim, K. B. (2015). Safety Evaluation of Polyethylene Glycol (PEG) Compounds for Cosmetic Use.Toxicological research,31(2), 105–136.https://doi.org/10.5487/TR.2015.31.2.105 
  3. Veronese, F. M., & Mero, A. (2008). The impact of PEGylation on biological therapies.BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy,22(5), 315–329.https://doi.org/10.2165/00063030-200822050-00004 
  4. Dabaja A, Dabaja A, Abbas M. Polyethylene Glycol. [Updated 2021 Dec 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:https://www.ncbi.nlm.nih.gov/books/NBK557652/ 
  5. Al-Nasassrah, M. A., Podczeck, F., & Newton, J. M. (1998). The effect of an increase in chain length on the mechanical properties of polyethylene glycols.European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V,46(1), 31–38.https://doi.org/10.1016/s0939-6411(97)00151-3