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CAS 25322-68-3 High-MW PEG (Osmotic Laxative Base) High-MW PEG (Osmotic Laxative Base)

Polyethylene Glycol 3350

IUPAC: Poly(ethylene glycol), average Mn 3350 View on PubChem
CAS NUMBER
25322-68-3
MOL. FORMULA
H(OCH2CH2)nOH (n˜76)
MOL. WEIGHT
~3,350 g/mol
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Scientific Overview

At its higher molecular weight, PEG 3350 is not absorbed from the GI tract and instead exerts an osmotic effect, drawing water into the bowel lumen to soften stool. This makes it the active ingredient in over-the-counter and prescription osmotic laxatives, in addition to its excipient roles as a solid-dosage-form binder and coating plasticizer.

Polyethylene Glycol 3350 is a mid-to-high molecular weight, water-soluble solid PEG grade used both as the active ingredient in osmotic laxative products and as a tablet-coating/binding excipient in solid oral dosage forms.

Full Technical Data
Chemical Name Polyethylene Glycol 3350 (PEG 3350; Macrogol 3350)
CAS Number 25322-68-3
IUPAC Name Poly(ethylene glycol), average Mn 3350
Molecular Formula H(OCH2CH2)nOH (n˜76)
Molecular Weight ~3,350 g/mol g/mol
Density 1.20 g/cm³ (solid)
Reaction Scheme
Ethylene Oxide
NA
NA
Polyethylene Glycol 3350
NA
Commercial Applications

Osmotic Laxative Active Ingredient

Used as the active ingredient in OTC and prescription products for occasional constipation and bowel prep.

Tablet Binder & Coating Plasticizer

Functions as a binder and film-coating plasticizer in solid oral dosage manufacturing.

Bowel Preparation Solutions

Core component of colonoscopy bowel-preparation electrolyte solutions.

Protein & Biologics Precipitation

Used in laboratory and downstream bioprocessing to precipitate and concentrate proteins.

Market Therapeutic Focus
HIGH-MW PEG (OSMOTIC LAXATIVE BASE) PHARMACEUTICAL MANUFACTURING GASTROENTEROLOGY THERAPEUTICS SOLID ORAL DOSAGE MANUFACTURING SPECIALTY EXCIPIENTS CRO/CDMO
Scientific Literature

Polyethylene Glycol 3350 in the Treatment of Chronic Constipation

Authors: DiPalma, J.A. et al.

Am. J. Gastroenterol.

DOI: 10.1111/j.1572-0241.2007.01297.x

Polyethylene Glycols and Their Applications in Drug Delivery

Authors: D'souza, A.A.; Shegokar, R.

Expert Opin. Drug Deliv.

DOI: 10.1517/17425247.2016.1142524

Use of PEG Precipitation to Concentrate and Purify Proteins

Authors: Ingham, K.C.

Methods Enzymol.

DOI: 10.1016/0076-6879(90)82008-P
Peer Queries & FAQs
Why doesn't PEG 3350 get absorbed like PEG 400?
Its much larger molecular size prevents significant intestinal absorption, so it stays in the gut lumen and works osmotically rather than systemically.
What is PEG 3350 used for besides being a laxative?
It also serves as a tablet binder, film-coating plasticizer, and a precipitating agent for protein purification in bioprocessing.
Is PEG 3350 the same compound as PEG 400?
Chemically, yes — both are polyethylene glycol sharing the same generic CAS number — but they differ greatly in molecular weight, physical state, and clinical use.
What is the recommended storage condition?
Store in a tightly sealed container at room temperature, protected from moisture, as the powder is hygroscopic.

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