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CAS 25322-68-3 High-MW Hydrophilic Polymer (Controlled-Release Matrix) High-MW Hydrophilic Polymer (Controlled-Release Matrix)

Polyethylene Oxide (PEO)

IUPAC: Poly(oxyethylene), high molecular weight View on PubChem
CAS NUMBER
25322-68-3
MOL. FORMULA
H(OCH2CH2)nOH (n>200; MW >100,000)
MOL. WEIGHT
100,000-7,000,000 g/mol (grade-dependent)
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Scientific Overview

At molecular weights exceeding roughly 100,000 Da, the polymer is conventionally termed 'polyethylene oxide' rather than 'polyethylene glycol.' Its extremely long chains form a gel layer upon hydration that controls drug diffusion and erosion rates, making PEO a key excipient in abuse-deterrent and sustained-release tablet technologies.

Polyethylene Oxide is the very high molecular weight grade of the polyethylene glycol/oxide polymer family, used as a hydrophilic matrix-forming polymer in controlled-release oral dosage forms and as a viscosity-modifying agent.

Full Technical Data
Chemical Name Polyethylene Oxide (PEO; high-MW Polyethylene Glycol)
CAS Number 25322-68-3
IUPAC Name Poly(oxyethylene), high molecular weight
Molecular Formula H(OCH2CH2)nOH (n>200; MW >100,000)
Molecular Weight 100,000-7,000,000 g/mol (grade-dependent) g/mol
Density 1.21 g/cm³
Reaction Scheme
Ethylene Oxide
NA
NA
Polyethylene Oxide (PEO)
NA
Commercial Applications

Controlled-Release Tablet Matrix

Forms a hydrating gel layer that controls drug release rate in sustained-release oral formulations.

Abuse-Deterrent Formulation Technology

High-MW PEO grades impart physical/rheological resistance to tampering in extended-release opioid products.

Mucoadhesive Drug Delivery

Used in bioadhesive tablet and film formulations for buccal and vaginal drug delivery.

Thickening & Rheology Modification

Functions as a viscosity modifier in pharmaceutical gels and topical formulations.

Market Therapeutic Focus
HIGH-MW HYDROPHILIC POLYMER (CONTROLLED-RELEASE MATRIX) PHARMACEUTICAL MANUFACTURING CONTROLLED & EXTENDED-RELEASE FORMULATION ABUSE-DETERRENT TECHNOLOGY SPECIALTY EXCIPIENTS CRO/CDMO
Scientific Literature

Polyethylene Oxide (PEO) as Versatile Excipients for Oral Extended-Release Tablets

Authors: Maderuelo, C. et al.

J. Control. Release

DOI: 10.1016/j.jconrel.2011.03.026

Abuse-Deterrent Formulations: Transitioning the Pharmaceutical Market to Improve Public Health and Safety

Authors: Raffa, R.B.; Pergolizzi, J.V.

J. Clin. Pharm. Ther.

DOI: 10.1111/j.1365-2710.2010.01213.x

High Molecular Weight Poly(ethylene oxide) in Drug Delivery and Biomedical Applications

Authors: Bailey, F.E.; Koleske, J.V.

Poly(ethylene oxide), Academic Press

Peer Queries & FAQs
What distinguishes PEO from lower-MW PEG grades?
Only its molecular weight — PEO refers to the same polyether chemistry at MW ranges above roughly 100,000 Da, where the material behaves as a true high-viscosity polymer rather than a liquid solvent.
How does PEO enable abuse-deterrent formulations?
Its high-MW grades form extremely viscous, difficult-to-inject gels when the tablet is crushed and dissolved, and resist rapid dose-dumping when extracted with common solvents.
Why is PEO used in controlled-release tablets?
On hydration it forms a slowly eroding gel layer around the tablet core that regulates the diffusion rate of the embedded drug.
What is the recommended storage condition?
Store in a tightly sealed container at room temperature, protected from moisture; very high-MW grades are also sensitive to mechanical/thermal degradation.

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