Estudo físico-químico, farmacotoxicológico e modelagem pkpd para desenvolvimento de uma nova formulação micelar de anfotericina B

Abstract

The increasing incidence of systemic fungal infections along with the growth of clinical isolates resistant to first line clinical treatment is a challenging epidemiological scenario in clinical practice. The development of new strategies is of paramount importance for the control of this rampant problem. Micellar amphotericin B (AmB-D) has a satisfactory activity profile, but its toxicity is pronounced. An alternative to reduce its toxicity is the controled heating of AmB-D resulting in superaggregates (AmB-H). Aiming a new therapeutic alternative, it was evaluated as structural modifications of AmB-H by accessing its physico-chemical characteristics, “in vitro” toxicity profile in red blood cells, “in vitro” activity in Candida sp strains and designed a semi-mechanistic PKPD model. A spectroscopy screening showed that there is a blue shift at the aggregate band from 327nm to 323nm, AmB-D and AmB-H respectively. The dilution study showed that AmB-H acts as the reservoir for the amphotericin B monomeric forms. Red blood cell toxicity studies have demonstrated that at high concentrations of AmB-H (5mg.L-1 and 50mg.L-1) presents around 2% of hemoglobin leakage whereas AmB-D presents the 100%, proving the profile of low toxicity by this experiment model. The activity evaluation, the AmB-H presented similar results to AmB-D against C. albicans and C. parapsiloses. The evaluation of the critical steps of the freeze-drying process, AmB-H has proven no changing during the process making it a good manufacturing strategy. Regarding the pharmacometrics, the semi-mechanistic PKPD model demonstrated that AmB-H is about 25% more potent than AmB-D and the model also provides quantitative parameters estimates that corroborate with a scientific literature and it provides a support to the development of clinical trials. All these data demonstrate that AmB-H is a promising system and together with scientific literature, it produces solid scientific subsidies to initiate clinical trials and finally the development of a new therapeutic strategy.