Development and characterization of gelatin and ethylcellulose microparticles designed as platforms to delivery fluoride

Abstract

Purpose: To develop and characterize microparticles containing fluoride sources (FS) from sodium fluoride, sodium monofluorophosphate (MFP) or aminofluoride and evaluate their characteristics as fluoride delivery systems.

Methods: Ethylcellulose microparticles containing fluoride (EM) were prepared by emulsification of ethyl acetate dispersion containing polymer and FS (ethylcellulose:FS ratio of 1:0.25 wt/wt) with aqueous external phase containing polysorbate 80 (0.8% vol/vol) using the volume ratio (organic:aqueous) of 1:5. The organic solvent was evaporated; microparticles were collected by centrifuging, washed with deionized water and freeze-dried. Gelatin microparticles containing FS (GM) was obtained by dispersion of the natural polymer in water, adding FS (6:1 wt/wt) and 20% (wt/wt) of mannitol. The final dispersions were spray-dried. Particle morphology and size were investigated using optical microscopy. The content of fluoride ions in the microparticles was quantified using a potentiometric method. The encapsulation efficiency and in vitro release profile of fluoride was also determined.

Results: Microparticles exhibited polydispersity and mean diameters <145.35 and <124.22 µm for EM and GM, respectively. Considering the entrapment efficiency, the spray-drying technique exhibited greater values than microencapsulation by emulsification and solvent evaporation. The release profile of fluoride ions from microparticles was shown to be modified, fitted first order and guided by Fickian diffusion.

Conclusions: Microparticles prepared with ethylcellulose or gelatin can be used as platform for oral delivery of fluoride, providing a means to increase the local supply of this ion in a controlled manner, providing an increased protection against caries. Moreover, further investigations are needed to demonstrate this property in vivo.

Keywords::

• Fluoride
• microparticles
• gelatin
• ethylcellulose
• in-vitro release

Acknowledgements

The authors are thankful to CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/Coordination for the Improvement of Higher Education), CNPq (Conselho Nacional de Pesquisa/National Research Council) and FINEP (Financiadora de Estudos e Projetos/Financier of Studies and Projects) for their financial support. Moreover, the authors thank the Research on Research Group, Duke University, USA.

Declaration of interest

The authors report no conflicts of interest.