Chagas disease (CD), caused by the flagellate protozoan Trypanosoma cruzi, is one of the major public health problems in developing countries. Benznidazole (BNZ) is the only drug available for CD treatment in most countries, however, it presents high toxicity and low bioavailability. To address these problems this study used Zeolitic Imidazolate Framework-8 (ZIF-8), which has garnered considerable attention due to its potential applications, enabling the controlled delivery of drugs. The present work developed and characterized a BNZ@ZIF-8 system, and the modulation of BNZ release from the ZIF-8 framework was evaluated through the in vitro dialysis release method under sink conditions at different pH values. Moreover, the in vitro evaluation of cell viability and cytotoxicity by MTT assay were also performed. The dissolution studies corroborated that a pH sensitive Drug Delivery System capable of vectorizing the release of BNZ was developed, may leading to the improvement in the bioavailability of BNZ. The MTT assay showed that no statistically significant toxic effects occurred in the developed system, nor significant effects on cell viability.

No abstract

Cirsiliol is a flavone found in many Lamiaceae species with high cytotoxic activity against tumor cell lines. Although cirsiliol is being used in cancer therapy, its pharmacological potential is limited by its low solubility and bioavailability. In this paper, a cirsiliol-β-cyclodextrin inclusion complex was developed in order to increase its solubility and bioavailability. The formation of inclusion complex was proved by scanning electron microscopy, Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) and solubility increment was verified through the ultraviolet-visible (UV-Vis) method. The cytotoxic effect against tumor cells (PC3, HCT-116 and HL-60 human cell lines, and S-180 murine cell line) and the antitumor activity in mice bearing sarcoma S-180 were also investigated. The inclusion complex was obtained with 71.45% of total recovery and solubility 2.1 times higher compared to the compound in its free form. This increment in solubility was responsible by a tumor growth inhibition potentiation (1.5 times greater compared to compound in its free form). In addition, this study showed that cirsiliol and its inclusion complex in β-cyclodextrin have strong antitumor potential at low doses without promoting side effects commonly observed for conventional drugs as doxorubicin.

The results show that BNZ only undergoes direct photodegradation, since no new PPs were found for a combination of the drug and excipients.

Chagas disease is a neglected tropical disease caused by the flagellate protozoan Trypanosoma cruzi (T. cruzi). Endemic in underdeveloped and developed countries, due to the migratory movement, it is considered a serious public health problem. Endemic in underdeveloped countries and due to the migratory movement, in developed countries as well, it is considered a serious public health problem. One of the reasons for this is a weak therapeutic arsenal, represented only by the drug benznidazole (BNZ) which, although it promotes significant cure rates in the acute phase of the disease, presents serious problems of toxicity and bioavailability, mainly due to its low aqueous solubility. Several studies have presented several drug delivery systems (DDS) based on BNZ aiming at enhancing its solubility in aqueous medium and, with this, promoting an increase in the dissolution rate and, consequently, in its bioavailability. However, the present work is a pioneer in using a zeolitic imidazolate framework as a carrier agent for a DDS in order to promote a pH-sensitive modulation of the drug. Thus, this work aimed to develop a novel DDS based on BNZ and the ZIF-8 to use it in development of prolonged-release dosage forms to alternative treatment of Chagas disease. The BNZ@ZIF-8 system was obtained through an ex situ method selected due to its higher incorporation efficiency (38%). Different characterization techniques corroborated the obtainment and drug release data were analyzed by in vitro dissolution assay under sink and non-sink conditions and setting the kinetic results through both model dependent and independent methods. Under sink conditions, at pH 4.5, BNZ and BNZ@ZIF-8 showed similar release profile, but the DDS was effective in promoting a prolonged release. At pH 7.6, after 7 h, BNZ showed a lower release than BNZ@ZIF-8. On the other hand, in non-sink conditions at pH 4.5 the BNZ presented 80% of drug release in 3 h, while the DDS in 6 h. At pH 7.6, BNZ presented a release of 80% in 2 h, while the DDS reaches it in only at 12 h. Therefore, at pH 4.5 the DDS BNZ@ZIF-8 showed a faster release with a burst effect, while at pH 7.6 it showed a prolonged and controlled release. Finally, it is evident that a promising DDS pH-sensitive was obtained as a novel carrier that might be able to prolongs BNZ release in dosage forms intended for the alternative treatment of Chagas disease.