Excellent solvents for a large number of substances that do not readily dissolve in water
Kollisolv® PEG 400
The low-molecular weight liquid polyethylene glycol Kollisolv® PEG 400 is an excellent solvent for a large number of substances that do not readily dissolve in water. They are therefore widely used as solvents and solubilising agents for active substances and excipients in liquid and semi-solid preparations. It is the ability of PEGs to form complexes with active substances that is responsible for their excellent solvent power. However, equilibrium constants for complex formation vary considerably from one substance to another, and certain drugs such as Penicillin G and Bacitracin can even become inactivated. The effect of the polyethylene glycol on the efficacy and absorbtion of a drug must therefore always be determined in tests. With regard to incompatible substances, please see the remarks in the European Pharmacopoeia, Vol. II/3, Monographs M1, Macrogol 300, p. 3. Polyethylene glycols can also be used to adjust the viscosity of liquid pharmaceutical preparations and ointments, to modify their absorption properties and to stabilise the preparation.