Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Tretinoin-loaded conventional nanocapsules have showed a significant protection of this drug against UVC radiation. However, this formulation presents a limited stability on storage. We hypothesized that the association of tretinoin to lipid-core nanocapsules could increase the physicochemical stability of such formulations, focusing on the development of a reliable nanomedicine for parenteral administration. However, this advantage should still be accompanied by the known photoprotective effect of conventional polymeric nanocapsules against the exposure of tretinoin to UV radiation. Results showed that tretinoin-loaded lipid-core nanocapsules improved the physicochemical stability of formulations under storage, without changing their ability to protect tretinoin either against UVA or UVC radiation. In addition, the effect of nanoencapsulation on the antiproliferative and differentiation properties of tretinoin was studied on human myeloid leukemia cells (HL60 cells) showing that tretinoin-loaded lipid-core nanocapsules presents a longer antitumor efficiency compared to the free tretinoin. These results allow us to propose the current formulation (tretinoin-loaded lipid-core nanocapsules) as a promising parenteral nanomedicine for the treatment of acute promyelocytic leukaemia.63214223Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)INCT-IFConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)