With a shorter average chain length than PEG 400, PEG 300 offers marginally lower viscosity and slightly different water-activity characteristics, making it preferred in certain soft-gelatin capsule and injectable formulations where flow properties are critical.
Polyethylene Glycol 300 is a low-molecular-weight liquid PEG grade slightly shorter-chain than PEG 400, used as a co-solvent and vehicle in injectable, oral, and topical pharmaceutical formulations requiring lower viscosity.
| Chemical Name | Polyethylene Glycol 300 (PEG 300; Macrogol 300) |
| CAS Number | 25322-68-3 |
| IUPAC Name | Poly(ethylene glycol), average Mn 300 |
| Molecular Formula | H(OCH2CH2)nOH (n6.5-6.9) |
| Molecular Weight | 285-315 g/mol g/mol |
| Density | 1.125 g/cm³ |
| Flash Point | 182°C |
Solubilizes lipophilic APIs in parenteral formulations requiring low-viscosity vehicles.
Used as a fill-solvent in soft-gelatin capsule formulations for poorly water-soluble drugs.
Functions as a humectant and solvent in topical gels, creams, and lotions.
Used as a co-solvent in oral liquid formulations, particularly for pediatric and veterinary products.
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