Functional Category
Antimicrobial preservative; humectant; solvent; water-miscible cosolvent
Applications in Pharmaceutical Formulation
Butylene glycol is used as a solvent and cosolvent for injectables.(1) It is used in topical ointments, creams, and lotions,(2–4) and it is also used as a vehicle in transdermal patches. Butylene glycol is a good solvent for many pharmaceuticals, especially estrogenic substances.(5) In an oil-in-water emulsion, butylene glycol exerts its best antimicrobial effects at 8% concentration.(6) Higher concentrations above 16.7% are required to inhibit fungal growth.(7
Description
Butylene glycol occurs as a clear, colorless, viscous liquid with a sweet flavor and bitter aftertaste.
Stability and Storage Conditions
Butylene glycol is hygroscopic and should be stored in a well-closed container in a cool, dry, well-ventilated place. When heated to decomposition, butylene glycol emits acrid smoke and irritating fumes.
Incompatibilities
Butylene glycol is incompatible with oxidizing reagents.
Safety
Butylene glycol is used in a wide variety of cosmetic formulations and is generally regarded as a relatively nontoxic material. It is mildly toxic by oral and subcutaneous routes. In topical preparations, butylene glycol is regarded as minimally irritant. Butylene glycol can cause allergic contact dermatitis, with local sensitivity reported in patch tests.(3,9–12) Some local irritation is produced on eye contact. LD50 (guinea pig, oral): 11.0 g/kg(8) LD50 (mouse, oral): 12.98 g/kg LD50 (rat, oral): 18.61 g/kg LD50 (rat, SC): 20.0 g/kg