The present invention relates to a useful method for preparing nanocapsules having a liquid lipid core and a solid shell and charged with at least one active agent having a hydrophilic character, said method comprising at least the steps consisting in: i) providing at least a first microemulsion having a water-in-oil character, stabilized by at least one lipophilic surfactant and containing in its hydrophilic phase at least one active agent having a hydrophilic character, providing at least a second microemulsion, separate from the first microemulsion, formulated by phase inversion of an emulsion and stabilized by at least one heat-sensitive, nonionic hydrophilic surfactant iii) adding said first microemulsion to said second microemulsion under conditions propitious for the formation of a novel microemulsion architecture in which said hydrophilic active agent remains present in the hydrophilic phase of the first microemulsion and iv) chill-hardening the mixture formed in the previous step, so as to obtain nanocapsules comprising said hydrophilic active agent and being formed from a lipid core, which is liquid at room temperature, and encapsulated in a film which is solid at room temperature.Further, the invention relates to nanocapsules which are able to be obtained by said method.
