Ingredients in PEG Powder
PEG powder (Polyethylene Glycol 3350) is a synthetic polymer consisting solely of polyethylene glycol with an average molecular weight of 3350, formulated as a white powder without electrolytes. 1
Primary Active Ingredient
- PEG 3350 is the only active ingredient, with the chemical formula HO(C2H4O)nH, where "n" represents the average number of oxyethylene groups 1
- The molecular weight ranges from 90.0% to 110.0% of the nominal 3350 value 1
- It is a long-chain polymer of ethylene oxide that functions as an osmotic laxative 2
Physical Properties and Formulation
- PEG 3350 powder is available as a white, free-flowing powder that is freely soluble in water below 55°C 1
- The standard over-the-counter formulation comes in an 8.3-oz bottle (238 g) 2
- No electrolytes are included in the standard PEG 3350 powder formulation, making it a hypotonic solution when mixed with water 2
Important Distinction from Other PEG Formulations
- PEG 3350 powder differs from PEG-electrolyte solutions (PEG-ELS), which contain added sodium sulfate, sodium bicarbonate, sodium chloride, and potassium chloride 2
- The electrolyte-free formulation allows mixing with various liquids including water, juice (prune, pear, apple), coffee, or tea 3
- For bowel preparation, clinicians often prescribe mixing one bottle with 64 ounces of Gatorade to create a 2-L formulation, though this is an off-label use 2
Manufacturing Considerations
- PEG is produced through condensation of ethylene oxide and water 4
- The manufacturing process should remove potential contaminants including unreacted ethylene oxide residues and 1,4-dioxane (a byproduct of ethoxylation) 5
- There is no likelihood of ethylene glycol or its monoalkyl ethers being present in properly manufactured PEG 3350 5
Common Pitfall to Avoid
- Do not confuse PEG 3350 powder with PEG-electrolyte solutions or other PEG derivatives used in cosmetics or pharmaceuticals, as these contain additional ingredients and have different molecular weights 2, 4
- The hypotonic nature of PEG 3350 powder without electrolytes creates a theoretical risk of hyponatremia, though studies show this risk is minimal with proper dosing and split-dose regimens 2, 6