Provided is a method for preparing nanocapsules having a liquid lipid core and a solid shell and charged in their lipid core with at least one hydrophilic active agent involving combining microemulsions where the active agent remains in the hydrophilic phase of a first microemulsion and chill-hardening the mixture to obtain the nanocapsules charged with the hydrophilic active agent. The nanocapsules comprise the lipid core which is liquid at room temperature and the nanocapsules are encapsulated in a film which is solid at room temperature.