Síntese, caracterização e avaliação da atividade antimicrobiana da amicacina microencapsulada ao polímero policaprolactona

Abstract

Gram negative bacteria such as Klebsiella pneumoniae (KP) and Pseudomonas aeruginosa (PA) are commonly found in hospital infections and they possess efficient mechanisms of antimicrobial resistance generally. The purpose of this study was to synthesize, characterize and evaluate the antimicrobial activity of the microencapsulated antibiotic amikacin towards polymer polycaprolactone (PCL) by encapsulating the drug Amikacin against the PA and KP bacteria. The microparticles were synthesized by solvent emulsification / evaporation technique, then they were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Visible Ultraviolet Spectroscopy (UV-Vis). The susceptibility of the bacteria was evaluated by disc-diffusion tests and microdilution technique according to the alamarblue® protocol, that indicates the percentage of cell reduction and minimum inhibitory concentration of the encapsulates. The morphological analysis in MEV characterized PCL microparticles with a mean diameter of 2,016 μm, with integral and uniform structures. In FTIR a similar graph was shown only between the encapsulated drug and the polymer, it suggests that the particles are coated just with PCL, whereas the drug is possibly inserted into the particle. UV-Vis indicated an absorption zone of inhibition centered around 281nm and 205nm that indicates a characteristic of PCL related to carbonyl groups and amikacin, respectively. Regarding the encapsulation, the minimum inhibitory concentration under KP was 0.0078mg / ml for pure drug 0.000489mg / ml and, as for AP, the CIM was 0.015mg / ml for the encapsulated while the pure was 0.002mg / ml. In the diffusion disc the averages of PA zones of inhibition were 19,40 mm for acid encapsulation and 25.91 mm for pure drug while in KP 15.2 mm and 17.4 mm, respectively. It can be concluded that the synthesis of the particles was effected in the scale of microcapsules, and it suggests that the drug is inserted in the particle while the surface is coated by PCL. In the microbiology the encapsulations were promising, with proven of the antimicrobial activity, but it requires future studies to make the clinical practice possible.