SB-83, a 2-Amino-thiophene derivative orally bioavailable candidate for the leishmaniasis treatment. 
Leishmaniasis, affecting more than 12 million people worldwide has become a severe public-health problem.  The therapeutic arsenal against leishmaniasis is mainly administered by parenteral route; it is toxic, expensive, and associated with recurrence risk.  The need for further therapeutic compounds research is pressing.  In previous studies, we demonstrated the antileishmanial activities of ten 2-amino-thiophene derivatives, which evidenced the action of a compound, called SB-83, having expressive antileishmania activity in an in vitro infection model.  In the present work, we describe preclinical studies of the thiophenic derivative SB-83, such as acute toxicity, genotoxicity, in vivo oral efficacy in a murine model, and in vitro antileishmanial activity against an L. amazonensis SbIII-resistant strain.  Determining acute preclinical toxicity, the LD50 of SB-83 was estimated at 2500 mg/kg orally, with few behavioral changes in Swiss mice.  Further, treatment with 2000 mg/kg of SB-83 did not induce in vivo genotoxic activity in the peripheral blood micronucleus assay.  In 7 weeks of oral treatment, SB-83 reduced paw lesion size in L. amazonensis infected mice by 52.47 ± 5.32%, and decreased the parasite load of the popliteal lymph node and spleen at the highest dose tested (200 mg/kg) respectively by 42.57 ± 3.14%, and 100%, without presenting weight change or other changes of clinical importance in the biochemical and hematological profiles.  The treatment of promastigotes and intracellular amastigotes of SbIII sensitive and resistant strains with SB-83 did not produce differences in antileishmania activity, which suggests no cross-resistance.  Thus, this work demonstrated that SB-83 has potential as a new active drug candidate even when orally administered, which may become a new therapeutic alternative for the treatment of leishmaniasis.