title: Physicochemical Stability of Compounded Creams Containing a-Hydroxy Acids.
abstract: The stability of creams containing the a-hydroxy acids (AHAs), lactic acid and glycolic acid, extemporaneously added to aqueous cream, BP or hydrophilic oinment, USP and subjected to five freeze-thaw cycles ranging form -4 to 40 deg C was studied. The pH, viscosity, spreadability, density, appearance and potency were measured after each freeze-thaw cycle. Compounding with hydrophilic ointment, USP produced the most stable creams; but the addition of the AHAs caused a significant decrease in preservative levels. The preservatives methylparaben and propylparaben were not hydrolyzed in the hydrophilic creams if the AHA ws partially neutralized to pH above 3.5.
authors.affiliation: Research Institute for Industrial Pharmacy Potchefstroom University for CHE Potchefstroom, South Africa.
authors.forename: M M
authors.initials: MM
authors.lastname: de Villiers
authors.forename: K
authors.initials: K
authors.lastname: Narsai
authors.forename: J G
authors.initials: JG
authors.lastname: van der Watt