Abstract: The invention relates to a process for preparing a chitosan-containing microcapsules and emulsions of an oil including the steps of (a) forming an oil-in-water emulsion by homogenizing said oil into an aqueous solution containing an anionic emulsifier; and (b) adding to the emulsion obtained in (a) an aqueous chitosan solution while continuously homogenizing the mixture to give a stable emulsion, which is converted into microcapsules by using the proper electrolyte and pH changes. Also encompassed are preparations including as active ingredient a lice repelling agent, vitamin E or a UV radiation photoprotectant. The preparations may be sustained-release or long acting preparations.

Abstract: The invention relates to sustained-release biodegradable lice repelling preparations comprising as active ingredient a lice repelling agent comprising at least one natural oil selected from the group consisting of citronella oil, rosemary oil and eucalyptus oil, or at least one natural oil component selected from the group consisting of citronellal and geraniol or mixtures thereof and further comprising an anionic emulsifier and chitosan, optionally further comprising dermatologically acceptable additives, carriers or diluents. The preparations may be in the form of an aqueous emulsion or chitosan microcapsules, preferably prepared by the processes of the invention.