Major benznidazole metabolites in patients treated for Chagas disease: Mass spectrometry-based identification, structural analysis and detoxification pathways.

Benznidazole is the drug of choice for the treatment of Chagas disease, but its metabolism in humans is unclear. Here, we identified and characterized the major benznidazole metabolites and their biosynthetic mechanisms in humans by analyzing the ionic profiles of urine samples from patients and untreated donors through reversed-phase UHPLC-ESI-QTOF-MS and UHPLC-ESI-QqLIT-MS. A strategy for simultaneous detection and fragmentation of characteristic positive and negative ions was employed using information-dependent acquisitions (IDA). Selected precursor ions, neutral losses, and MS3 experiments complemented the study. A total of six phase-I and ten phase-II metabolites were identified and structurally characterized in urine of benznidazole-treated patients. Based on creatinine-corrected ion intensities, nitroreduction to amino-benznidazole (M1) and its subsequent N-glucuronidation to M5 were the main metabolic pathways, followed by imidazole-ring cleavage, oxidations, and cysteine conjugations. This extensive exploration of benznidazole metabolites revealed potentially toxic structures in the form of glucuronides and glutathione derivatives, which may be associated with recurrent treatment adverse events; this possibility warrants further exploration in future clinical trials. Incorporation of this knowledge of the benznidazole metabolic profile into clinical pharmacology trials could lead to improved treatments, facilitate the study of possible drug-drug interactions, and even mitigation of adverse drug reactions.

[The toxicity of venom of Bothrops (Rhinocerophris) alternatus in different areas of Cordoba State in Argentina]. / Caracterización tóxica del veneno de Bothrops (Rhinocerophis) alternatus de diferentes regiones de la provincia de Córdoba (Argentina).

Snake venoms can show biochemical and toxicological variability even in specimens from the same specie. The geographical localization of the snakes is one of the factors that can influence those variations. By these reasons the venom from specimens of Bothrops (Rhinocerophis) alternatus ("crucera", "yararágrande"), one of the snakes of highest medical importance in Argentina, from three different regions of Córdoba was studied. Lehtal potency, hemorrhagic, coagulant on plasma and thrombin like activities as well as the electrophoretic patterns of venom from snakes of Calamuchita, Traslasierras and the East of the province were determined. The venom from the snakes of the three regions showed the characteristic activities of the venom of the majority of Bothrops, causing hemorrhage, hemostatic disturbances acting on plasma or directly on fibrinogen with a "thrombin like activity". The different samples were very similar regarding their biochemical characteristics and toxic potencies at difference of previous observations on venoms from the same specie in different regions of other provinces fro Argentina. Bivalent antivenom, the one used by the Provincial Ministry of Health to treat the bothropic accidents, neutralized in all the cases the toxic activities of the venom in very similar range of neutralizing potency.

Los venenos serpientes pueden presentar variabilidad en sus características bioquímicas y toxicológicas aún en ejemplares de una misma especie. La localización geográfica de los ejemplares es uno de los factores que puede influenciar estas variaciones. Por este motivo se estudió el veneno de ejemplares Bothrops (Rhinocerophis) alternatus ("crucera", "yarará grande"), una de las serpientes de mayor importancia médica de Argentina, de tres regiones diferentes de Córdoba. Se estudió la potencia letal, la actividad hemorrágica, coagulante en plasma y trombina símil y el patrón electroforético de ejemplares de Calamuchita, Traslasierras y del Este de la provincia. El veneno de las serpientes de las tres regiones presentó las actividades características de los venenos de la mayoría de las Bothrops, causando hemorragias y alteraciones en el sistema hemostático, afectando tanto al plasma como actuando directamente sobre el fibrinógeno mediante una actividad trombina símil. Las distintas muestras fueron muy similares en cuanto a sus características bioquímicas ya sus potencias tóxicas, a diferencia de lo observado con veneno de ejemplaresB. alternatusde distintas regiones de otras provincias de la Argentina. El antiveneno Bivalente utilizado por el Ministerio de Salud de Córdoba para tratar los accidentes por Bothrops neutralizó, en todos los casos las actividades tóxicas ensayadas en rangos de potencias neutralizantes muy similares.

Caracterización tóxica del veneno de Bothrops (Rhinocerophis) alternatus de diferentes regiones de la provincia de Córdoba (Argentina) / [The toxicity of venom of Bothrops (Rhinocerophris) alternatus in different areas of Cordoba State in Argentina].

Snake venoms can show biochemical and toxicological variability even in specimens from the same specie. The geographical localization of the snakes is one of the factors that can influence those variations. By these reasons the venom from specimens of Bothrops (Rhinocerophis) alternatus ("crucera", "yararágrande"), one of the snakes of highest medical importance in Argentina, from three different regions of Córdoba was studied. Lehtal potency, hemorrhagic, coagulant on plasma and thrombin like activities as well as the electrophoretic patterns of venom from snakes of Calamuchita, Traslasierras and the East of the province were determined. The venom from the snakes of the three regions showed the characteristic activities of the venom of the majority of Bothrops, causing hemorrhage, hemostatic disturbances acting on plasma or directly on fibrinogen with a "thrombin like activity". The different samples were very similar regarding their biochemical characteristics and toxic potencies at difference of previous observations on venoms from the same specie in different regions of other provinces fro Argentina. Bivalent antivenom, the one used by the Provincial Ministry of Health to treat the bothropic accidents, neutralized in all the cases the toxic activities of the venom in very similar range of neutralizing potency.