First-Row Transition 7-Oxo-5-phenyl-1,2,4-triazolo[1,5-a]pyrimidine Metal Complexes: Antiparasitic Activity and Release Studies Martín Montes, Álvaro Miguel Jiménez-Falcao, Sandra Gómez-Ruiz, Santiago Marín Sánchez, Clotilde Méndez Arriaga, José Manuel Metal complex Coordination chemistry Leishmaniasis Antiparasitic activity Drug release Nanoparticles We are thankful for the funding from the research project RTI2018-094322-B-I00, financed by MCIN/AEI/10.13039/501100011033/; “ERDF A way of making Europe”; and the Research Thematic Network RED2022-134091-T, financed by MCIN/AEI/10.13039/501100011033. Á.M.-M. is grateful to the European Union and Junta de Andalucía for a post-doc grant (Ayuda a la contratación de personal investigador doctor). Supplementary Materials: The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/ph16101380/s1 Leishmaniasis and Chagas disease are still considered neglected illnesses due to the lack of investment in research, despite the fact that almost one million new cases are reported every year. Four 7-oxo-5-phenyl-1,2,4-triazolo[1,5-a]pyrimidine (HftpO) first-row transition complexes (Cu, Co, Ni, Zn) have been studied for the first time in vitro against five different species of Leishmania spp. (L. infantum, L. braziliensis, L. donovani, L. peruviana and L. mexicana) as well as Trypanosoma cruzi, showing higher efficacy than the reference commercial drugs. UV and luminescence properties were also evaluated. As a proof of concept, anchoring of a model high-effective-metal complex as an antiparasitic agent on silica nanoparticles was carried out for the first time, and drug-release behaviour was evaluated, assessing this new approach for drug vehiculation. 2023-11-29T13:38:07Z 2023-11-29T13:38:07Z 2023-09-28 journal article Martín-Montes, Á.; Jimenez-Falcao, S.; Gómez-Ruiz, S.; Marín, C.; Mendez-Arriaga, J.M. First-Row Transition 7-Oxo-5-phenyl- 1,2,4-triazolo[1,5-a]pyrimidine Metal Complexes: Antiparasitic Activity and Release Studies. Pharmaceuticals 2023, 16, 1380. [https://doi.org/10.3390/ph16101380] https://hdl.handle.net/10481/85931 10.3390/ph16101380 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional MDPI