Preparation, Characterization and Biological Activity of Cathelicidin-BF-30-Loaded Poly(LA-co-MA) Microspheres

Antimicrobial peptides have a great potential to replace antibiotics in the treatment of bacterial infections. In order to improve the its stability, the antimicrobial peptides were incorporated in poly(L-lactic acid-co-D, L-mandelic acid) (LA-co-MA) microspheres prepared by a double emulsion solvent evaporation method. In this study, the microspheres obtained had a mean particle size of 2.75 +/- 0.2 mu m, Encapsulation Efficiency (EE) of 92.47 +/- 1.21% and drug loading of 8.44 +/- 0.11%. The peptides were released from poly(LA-co-MA) microspheres at a constant speed and no significant initial burst effect was observed. The secondary structure and antibacterial activity of the released peptide were retained, which were compared with those of the native peptides. In addition, these BF-30-loaded microspheres presented <5% hemolysis and no toxicity for HEK293 cells even at the highest tested concentration (150 mu g/mL), indicating that the poly(LA-co-MA) microspheres are promising carriers for peptides.