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Tetracycline-Loaded Biomimetic Apatite: An Adsorption Study

Cazalbou, Sophie and Bertrand, Ghislaine and Drouet, Christophe Tetracycline-Loaded Biomimetic Apatite: An Adsorption Study. (2015) The Journal of Physical Chemistry B, 119 (7). 3014-3024. ISSN 1520-6106

(Document in English)

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Official URL: http://dx.doi.org/10.1021/jp5116756


Biomimetic apatites are appealing compounds for the elaboration of bioactive bone-repair scaffolds due to their intrinsic similarity to bone mineral. Bone surgeries are however often heavy procedures, and the infiltration of pathogens may not be totally avoided. To prevent their development, systemic antibiotic prophylaxis is widespread but does not specifically target surgical sites and involves doses not always optimized. A relevant alternative is a preliminary functionalization by an infection-fighting agent. In this work, we investigated from a physicochemical viewpoint the association of a wide-spectrum antibiotic, tetracycline (TC), and a biomimetic nanocrystalline apatite previously characterized. TC adsorption kinetics and isotherm were thoroughly explored. Kinetic data were fitted to various models(pseudo-first-order, pseudo-second-order, general kinetic model of order n, Elovich, double-exponential, and purely diffusive models). The best fit was found for a doubleexponential kinetic model or with a decimal reaction order of 1.4, highlighting a complex process with such TC molecules which do not expose high-affinity end groups for the surface of apatite. The adsorption isotherm was perfectly fitted to the Sips (Langmuir−Freundlich) model, while other models failed to describe it, and the Sips exponent greater than unity (1.08) suggested a joint impact of surface heterogeneity and positive cooperativity between adsorbed molecules. Finally, preliminary insights on TC release from pelletized nanocrystalline apatite, in aqueous medium and neutral pH, were obtained using a recirculation cell, indicating a release profile mainly following a Higuchi-like diffusion-limited rate. This work is intended to shed more light on the interaction between polar molecules not exhibiting high-affinity end groups and biomimetic apatites and is a starting point in view of the elaboration of biomimetic apatite-based bone scaffolds functionalized with polar organic drugs for a local delivery.

Item Type:Article
Additional Information:Thanks to American Chemical Society editor. The definitive version is available at http://pubs.acs.org The original PDF of the article can be found at American Chemical Society website : http://pubs.acs.org/doi/abs/10.1021/jp5116756
HAL Id:hal-01194810
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:07 Sep 2015 13:48

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