Journal Article

Gentamicin-loaded microspheres for reducing the intracellular <i> Brucella abortus</i> load in infected monocytes

Sandra Prior, Bruno Gander, Concepción Lecároz, Juan M. Irache and Carlos Gamazo

in Journal of Antimicrobial Chemotherapy

Published on behalf of British Society for Antimicrobial Chemotherapy

Volume 53, issue 6, pages 981-988
Published in print June 2004 | ISSN: 0305-7453
Published online June 2004 | e-ISSN: 1460-2091 | DOI:
Gentamicin-loaded microspheres for reducing the intracellular  Brucella abortus load in infected monocytes

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Objectives: The intracellular antibiotic efficiency of gentamicin-loaded microspheres in the context of Brucella-infected murine monocytes was examined in vitro with a view to developing improved therapies for the treatment of brucellosis.

Methods: Biodegradable microspheres made of end-group capped and uncapped poly(lactide-co-glycolide) 50:50 (PLGA 50:50 and PLGA 50:50H) and containing gentamicin sulphate were used to target Brucella abortus-infected J774 monocyte-macrophages. The infected cells were treated with 15 µg of free or microencapsulated gentamicin and the efficacy of the treatments was measured after 24 h.

Results: The particle sizes were below 8 µm and in vitro release of gentamicin from the microspheres followed a continuous (PLGA 50:50H) or a multiphasic (PLGA 50:50) pattern over 50 days. Treatment with gentamicin microencapsulated into the end-group uncapped PLGA 50:50H microspheres, decreased significantly the number of intracellular bacteria (typically by 2 log10) in comparison with untreated infected cells. Addition of 2% poloxamer 188 to the microsphere dispersion medium further reduced the infection (3.5 log10). Opsonization of the particles with non-immune mouse serum had no effect on the antibacterial efficacy of the microspheres. End-group capped PLGA 50:50 type microspheres containing the antibiotic were less effective at reducing intracellular bacteria (∼1 log10 reduction), although addition of poloxamer 188 to the dispersion medium again enhanced their intracellular antibacterial activity. Placebo PLGA 50:50 and PLGA 50:50H microspheres had no bactericidal activity.

Conclusions: The results indicate that PLGA 50:50-microencapsulated gentamicin sulphate may be suitable for efficient drug targeting and delivery to reduce intracellular Brucella infections.

Keywords: Keywords: biodegradable microspheres, drug delivery systems, Brucella-infected monocytes

Journal Article.  5751 words.  Illustrated.

Subjects: Medical Oncology ; Critical Care

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