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Development of an oral feed additive against intestinal infections based on microparticles’ systems loaded with Ctx(Ile21)-Ha peptide coated with HPMCAS/Chitosan
* 1 , 2 , 3 , 4 , 5 , 2 , 3 , 5 , 1 , 2 , * 6
1  Tuberculosis Research Laboratory, School of Pharmaceutical Sciences, São Paulo State University (UNESP).
2  School of Agricultural and Veterinarian Sciences, São Paulo State University (UNESP), Jaboticabal, Sao Paulo, Brazil.
3  School of Technology and Sciences, Presidente Prudente, São Paulo State University (UNESP), Presidente Prudente, Sao Paulo, Brazil.
4  Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca, Talca, Chile.
5  School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Sao Paulo, Brazil.
6  School of Sciences and Engineering, São Paulo State University (UNESP), Tupã, São Paulo, Brazil.
Academic Editor: Jean Jacques Vanden Eynde

Abstract:

In recent decades, resistant bacteria have generated a worldwide concern, since prolonged exposure to different compounds produces or acquires these mutations. The Ctx(Ile21)-Ha antimicrobial peptide is widely studied by our research group, proved to be effective against multidrug-resistant bacteria and Salmonella enteritidis, both in in vitro and in vivo studies. However, its oral administration is affected by external factors that induce degradation. In this study, Ctx(Ile21)-Ha peptide was synthesized in solid-phase peptide synthesis and characterized by LC/MS. Alginate microparticles loaded with the peptide were produced by ionic gelation and coated with hypromellose acetate/succinate and chitosan by immersion. Microparticles developed were characterized by SEM, DSC/TGA, XDR. Antimicrobial evaluation against intestinal bacteria and gastrointestinal release profile was performed. The results showed an encapsulation efficiency of 84.52%. In addition, they corroborated the presence and stability of the peptide throughout its release and enzymatic hydrolysis. Also, the antibacterial activity, depending on the strain tested, was around 16-128 μg of Ctx(Ile21)-Ha. The crystallinity of the compounds was slightly modified to a semi-amorphous state, although thermal stability was maintained up to 80°C. The results showed high physicochemical stability since this peptide has strong characteristics of the frog skin from which it was initially isolated. The peptide-controlled release was achieved, and the hydrolysis and degradation produced by gastric pH could be prevented. In conclusion, the administration of encapsulated/coated antimicrobial peptides would be a new option for the treatment of intestinal diseases, including resistant pathogens.

Keywords: AMP; drug delivery; encapsulation; intestinal infection; medicinal chemistry; microparticles; solid phase synthesis.
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