The preservation of Lanette Wax Cream (FNA)

Abstract

Factors influencing the free concentration methylparaben in Lanette Wax Cream (FNA) were studied. These factors are the partitioning of the preservative between oil and water phase and solubilisation by the micelles of emulsifier, sodium lauryl sulphate. Solubilisation could be described as simple partitioning provided that the free concentration of methylparaben did not exceed o. t % (w/v). The influence of propylene glycol on partitioning and solubilisation was also studied.Microbiological studies were performed on five creams differing only in preservative system viz. 0.2% and 0.4% methylparaben, 2o% propylene glycol, o.4% methylparaben + 2o% propylene glycol, and o.15% sorbic acid. A formulation containing o. I5% sorbic acid was preferred. (Pharm. Weekblad Sci. Ed. 2,(19)(20)(21)(22)(23)(24)