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Chitosan microparticles for the controlled delivery of fluoride.
J Dent. 2012 Mar; 40(3):229-40.JD

Abstract

OBJECTIVES

To manufacture and characterise chitosan/fluoride microparticles prepared by spray drying and assess their utility as controlled release vehicles for fluoride.

METHODS

Microparticles were manufactured from dispersions containing 1.0% and 2.0% (w/v) chitosan and 0.20% or 0.40% (w/v) NaF in the absence/presence of glutaraldehyde. Particle size distributions were determined using laser diffraction; fluoride loading and release were determined by ion-selective electrode. Release profiles were studied in isotonic media (pH 5.5) over 360 min; microparticles exhibiting greatest cumulative fluoride release were further evaluated at pH 4.0 and 7.0. Particle morphology was investigated using environmental scanning electron microscopy. Bioadhesion parameters were determined with a texture-probe analyser.

RESULTS

Microparticles exhibited low polydispersity and volume mean diameters (VMDs) <6 μm. VMDs increased on doubling the chitosan/fluoride concentrations but were largely independent of glutaraldehyde concentration. Recovered yields were inversely proportional to dispersion viscosity due to compromised fluid atomisation; adding NaF reduced viscosity and improved yields. Best-case entrapment efficiency and NaF loading were 84.1% and 14%, respectively. Release profiles were biphasic, releasing 40-60% of the total fluoride during the first 600 s, followed by a prolonged release phase extending out to 6h. Incorporation of 0.40% NaF to the 2.0% chitosan dispersion yielded microparticles with reduced bioadhesive parameters (F(max) and WOA) versus the chitosan-only control whilst retaining significant bioadhesive potential.

CONCLUSIONS

Bioadhesive chitosan/fluoride microparticles manufactured using a spray-drying protocol have been extensively characterised and further opportunity for optimisation identified. These microparticles may provide a means of increasing fluoride uptake from oral care products to provide increased protection against caries, however further work is required to demonstrate this principle in vivo.

CLINICAL SIGNIFICANCE

Spray-drying is a low-cost route for the manufacture of bioadhesive chitosan/fluoride microparticles which can be exploited as controlled fluoride release agents to aid fluoride retention in the oral cavity. The potential exists to optimise release profiles to suit the delivery format thereby maximising the cariostatic benefits.

Authors+Show Affiliations

Chiesi Ltd., Chippenham, Wiltshire SN14 0AB, UK.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22212236

Citation

Keegan, Gemma M., et al. "Chitosan Microparticles for the Controlled Delivery of Fluoride." Journal of Dentistry, vol. 40, no. 3, 2012, pp. 229-40.
Keegan GM, Smart JD, Ingram MJ, et al. Chitosan microparticles for the controlled delivery of fluoride. J Dent. 2012;40(3):229-40.
Keegan, G. M., Smart, J. D., Ingram, M. J., Barnes, L. M., Burnett, G. R., & Rees, G. D. (2012). Chitosan microparticles for the controlled delivery of fluoride. Journal of Dentistry, 40(3), 229-40. https://doi.org/10.1016/j.jdent.2011.12.012
Keegan GM, et al. Chitosan Microparticles for the Controlled Delivery of Fluoride. J Dent. 2012;40(3):229-40. PubMed PMID: 22212236.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Chitosan microparticles for the controlled delivery of fluoride. AU - Keegan,Gemma M, AU - Smart,John D, AU - Ingram,Matthew J, AU - Barnes,Lara-Marie, AU - Burnett,Gary R, AU - Rees,Gareth D, Y1 - 2011/12/23/ PY - 2011/07/18/received PY - 2011/12/14/revised PY - 2011/12/15/accepted PY - 2012/1/4/entrez PY - 2012/1/4/pubmed PY - 2012/7/21/medline SP - 229 EP - 40 JF - Journal of dentistry JO - J Dent VL - 40 IS - 3 N2 - OBJECTIVES: To manufacture and characterise chitosan/fluoride microparticles prepared by spray drying and assess their utility as controlled release vehicles for fluoride. METHODS: Microparticles were manufactured from dispersions containing 1.0% and 2.0% (w/v) chitosan and 0.20% or 0.40% (w/v) NaF in the absence/presence of glutaraldehyde. Particle size distributions were determined using laser diffraction; fluoride loading and release were determined by ion-selective electrode. Release profiles were studied in isotonic media (pH 5.5) over 360 min; microparticles exhibiting greatest cumulative fluoride release were further evaluated at pH 4.0 and 7.0. Particle morphology was investigated using environmental scanning electron microscopy. Bioadhesion parameters were determined with a texture-probe analyser. RESULTS: Microparticles exhibited low polydispersity and volume mean diameters (VMDs) <6 μm. VMDs increased on doubling the chitosan/fluoride concentrations but were largely independent of glutaraldehyde concentration. Recovered yields were inversely proportional to dispersion viscosity due to compromised fluid atomisation; adding NaF reduced viscosity and improved yields. Best-case entrapment efficiency and NaF loading were 84.1% and 14%, respectively. Release profiles were biphasic, releasing 40-60% of the total fluoride during the first 600 s, followed by a prolonged release phase extending out to 6h. Incorporation of 0.40% NaF to the 2.0% chitosan dispersion yielded microparticles with reduced bioadhesive parameters (F(max) and WOA) versus the chitosan-only control whilst retaining significant bioadhesive potential. CONCLUSIONS: Bioadhesive chitosan/fluoride microparticles manufactured using a spray-drying protocol have been extensively characterised and further opportunity for optimisation identified. These microparticles may provide a means of increasing fluoride uptake from oral care products to provide increased protection against caries, however further work is required to demonstrate this principle in vivo. CLINICAL SIGNIFICANCE: Spray-drying is a low-cost route for the manufacture of bioadhesive chitosan/fluoride microparticles which can be exploited as controlled fluoride release agents to aid fluoride retention in the oral cavity. The potential exists to optimise release profiles to suit the delivery format thereby maximising the cariostatic benefits. SN - 1879-176X UR - https://www.unboundmedicine.com/medline/citation/22212236/Chitosan_microparticles_for_the_controlled_delivery_of_fluoride_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0300-5712(11)00320-4 DB - PRIME DP - Unbound Medicine ER -