The present invention relates to nanoparticles comprising at least one negatively charged glycosaminoglycan-type macromolecule or a derivative thereof, non-covalently coupled to at least one molecule of a cationic hydrocarbon-based radical of squalene nature represented by the formula (I) which follows:wherein:A, B, C, D, E and F are a hydrogen atom or a methyl group Z and Y represent a radicalan ethyltrialkylammonium radical, an ethylguanidium radical or a 1-[ethylideneamino]guanidinium radical with the proviso that at least one of Z and Y is different fromthe symbol * showing the position of the attachment of the radical to the structure and n is equal to 1 or 2.The present invention also relates to a method for preparing said nanoparticles, and to a lyophilisate, a solid dosage form and pharmaceutical or dermatological compositions comprising said nanoparticles. Said nanoparticles are useful as medicines and more particularly as anticoagulant agents.