Abstract:

Hypothesis: Biopolymer–CaCO3 hybrid microparticles exposed to hydrolytic enzymes can provide new surface tailorable architectures. Soluble Alginate Lyase hydrolyzed alginate chains exposed on microparticle surface are generating considerable matrix changes. The change of porosity and surface to volume ratio is expected to influence absorption of drugs, thereby affecting controlled release profiles. The developed hybrid system potentially shows interesting properties for lung drug administration. Experimental: Hybrid microparticles were developed by colloidal co-precipitation of CaCO3 in presence of biopolymers: alginate (Alg) or Alg–High Methoxylated Pectin (HMP), followed by treatment with Alginate Lyase (AL). Surface architectures were observed by SEM. The increase in area to volume ratio was confirmed by BET isotherms. Also, enzymatic changes were elucidated by biophysical methods (EDAX, DSC, FTIR, XRD) and determination of the total carbohydrates content. Levofloxacin (a fluoroquinolone antibiotic) as model drug was incorporated by absorption. The drug release profile and the antimicrobial activity of the microparticles were tested against Pseudomonas aeruginosa. Findings: After enzyme treatment, microspheres showed 4 μm diameter and increased porosity. While CaCO3–Alg microspheres resulted in a rougher surface, CaCO3–Alg–HMP ones exhibited “nano-balloon” patterns on surface. Both AL-treated microparticles showed up to 3 and 7 times higher Levofloxacin encapsulation than no treated ones. Microparticles showed controlled drug release profiles and enhanced antimicrobial effect. The present work demonstrates a significant progress in the development of new carriers with potential application for lung infections treatment.

Author affiliation: Islan, German Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina

Author affiliation: Cacicedo, Maximiliano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina

Author affiliation: Bosio, Valeria Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina

Author affiliation: Castro, Guillermo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina

Abstract:

Current medical treatments against recurrent pulmonary infections caused by Pseudomonas aeruginosa, such as cystic fibrosis (CF) disorder, involve the administration of inhalable antibiotics. The main challenge is, however, the eradication of microbial biofilms immersed in dense mucus that requires high and recurrent antibiotic doses. Accordingly, the development of novel drug delivery systems capable of providing local and controlled drug release in the lungs is a key factor to improve the therapeutic outcome of such therapeutic molecules. Inhalable hybrid carriers were prepared by co-precipitation of CaCO3 in the presence of alginate and the resulting microparticles were treated with alginate lyase (AL) in order to modify their porosity and enhance the drug loading. The hybrid microparticles were loaded with DNase (mucolytic agent) and levofloxacin (LV, wide-spectrum antibiotic) in the range of 20-40% for LV and 28-67% for DNase, depending on the AL treatment. In vitro studies demonstrated that microparticles were able to control the DNase release for 24 h, while 30-50% of LV was released in 3 days. The morphological characterization was performed by optical, fluorescence and scanning electron microscopies, showing a narrow size distribution (5 mm). FTIR, XRD, DSC and nitrogen adsorption isotherm studies revealed the presence of the drugs in a non-crystalline state. A microcidal effect of microparticles was found on P. aeruginosa in agar plates and corroborated by Live/Dead kit and TEM observations. Finally, to study whether the microparticles improved the localization of LV in the lungs, in vivo studies were performed by pulmonary administration of microparticles to healthy mice via nebulization and dry powder inhalation, followed by the quantification of LV in lung tissue. The results showed that microparticles loaded with LV delivered the antibiotic at least 3 times more efficiently than free LV. The developed system opens the gateway to new drug delivery systems that may provide enhanced therapeutic solutions against bacterial infections and in particular as a potential tool in CF pathology.

Author affiliation: Islan, German Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina

Author affiliation: Ruiz, María Esperanza. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Morales, Juan Francisco. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Sbaraglini, Maria Laura. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Enrique, Andrea Verónica. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Burton, Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina

Author affiliation: Talevi, Alan. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Bruno Blanch, Luis Enrique. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina

Author affiliation: Castro, Guillermo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina