CONICET | Buscador de Institutos y Recursos Humanos

Rifampicin (RIF) is a potent antibiotic, active against certain Gram positive, Gram negative and populations of tuberculosis (TB) bacilli and other mycobacteria.1 RIF present poor oral bioavailability, which might result from the poor water solubility and low stability. Based on these observations, the aim of the present study was to prepare, characterize and evaluate the dissolution rate of RIF supramolecular systems with arginine (RIF:ARG).RIF:ARG supramolecular systems were prepared by drop assisted grinding, with the resulting solid materials being characterized by Fourier transform infrared spectroscopy (IR) and scanning electron microscopy (SEM). In addition, dissolution rate studies of both pure RIF and RIF:ARG system were conducted using a dissolution apparatus applying the paddle method. Tests were performed in 300 ml of simulated intestinal fluid without enzymes, at 37.0±0.5 ºC and stirring at 50 rpm. The parameter used to compare the dissolution curves were the similarity factor (f2).SEM images of the RIF:ARG systems evidence a change in the morphology of the particles and shows the adherence of smaller particles to the surface of larger particles of RIF. The IR spectra obtained for the RIF:ARG system show that the band of RIF at 1727 cm-1 (-C=O acetyl stretching) became broader and were shifted to 1714 cm-1 and confirm the existence of intermolecular interactions between RIF and ARG. In addition, when the dissolution curves were compare the f2 value calculated was 33. These results indicate that the curve of the RIF:ARG system was not similar to the curve of the drug alone, implying that the presence of ARG caused an enhancement of the RIF dissolution rate.Therefore, RIF:ARG system might be a promising alternative for the oral drug delivery of the drug used to treat bacterial infections.