Background/Objectives: Chagas disease is a neglected tropical disease caused by infection with the parasite Trypanosoma cruzi. Benznidazole and nifurtimox are the only approved drugs for treating this condition, but their low aqueous solubility may lead to erratic bioavailability. This work aimed for the first time to formulate tablets of nifurtimox by hot melt extrusion coupled with 3D printing as a strategy to increase drug dissolution and the production of tablets with dosage on demand. Methods: Different pharmaceutical-grade polymers were evaluated through film casting, and those with promising nifurtimox amorphization capacity were further used to prepare filaments by hot melt extrusion. The printability of the obtained filaments was tested, and the polyvinyl alcohol filament was further used for printing tablets containing 120 and 60 mg of nifurtimox. Results: Three-dimensional tablets showed a remarkable improvement in the drug dissolution rate compared to commercial tablets and a dissolution efficiency 2.8 times higher. In vivo studies were carried out on Swiss mice. Parasitemia curves of nifurtimox printed tablets were significantly superior to the pure drug. Moreover, NFX 3D tablets provided a similar Trypanosoma cruzi reduction in plasmatic concentration to benznidazole, the gold-standard drug for acute-phase treatment of the Chagas disease. Conclusions: The findings of this work showed that hot melt extrusion coupled with 3D printing is a promising alternative for increasing nifurtimox biopharmaceutical properties and an attractive approach for personalized medicine.

Background: In recent years, compounds known as Proteolysis Targeted Chimeras (PROTACs) have revitalized the field of bioactive molecule design. These compounds promote proteolysis of therapeutic targets by recruiting them to ubiquitin ligases. One of the most commonly used classes of compounds in the synthesis of PROTACs are immunomodulatory imides (IMiDs), such as thalidomide (TLD), which interact with the E3 ligase CRL4^CRBN via the CULT domain of the cereblon protein (CRBN). This domain has been identified in proteins across various phylogenetic groups, including trypanosomatids, leading to the hypothesis that IMiD-derived PROTACs should be active in these organisms. Methods: The trypanocidal activity of the PROTAC dBET1 and its separated components (JQ1 and TLD) were assayed using a T. cruzi strain expressing β-glalactosidase. Potential CRL4-E3L complexes from humans and trypanosomatids were assembled in silico with MultimerMapper. The IMiD-binding site of HsCRBN and its trypanosomatid homologs were analyzed using molecular dynamics and docking simulations. Results: We demonstrate that the compound dBET1 does not function as a PROTAC in Trypanosoma cruzi. In silico structural analysis of CRL4-E3L complex orthologs revealed that the trypanosomal CULT-containing protein is not part of such a complex. Molecular dynamics simulations showed that the pocket of this CULT domain is smaller than that of mammalian CRBN and cannot accommodate IMiDs within. Conclusions: We underscore the importance of functional and structural validation in drug discovery, particularly when extrapolating mechanisms between evolutionarily distant species. While PROTACs hold promise in human therapeutics, our work advocates for re-evaluating the rationale behind thalidomide-based PROTACs in trypanosomatid research.