title: Nanoparticles for controlled delivery and sustained release of chlorhexidine in the oral environment.
abstract: OBJECTIVE
  Chlorhexidine (CHX) is in widespread use as a topical antimicrobial agent. Within the field of oral medicine, it is used in the prevention of ventilator-associated pneumonia as well as in the treatment of oral candidosis and microbial-associated lichenoid reactions. The objective of this study was to develop a strategy for controlled, sustained topical delivery of CHX using nanoparticle technology.
  
  
  METHODS
  Chlorhexidine was applied to hydroxyapatite, selected as a tooth analogue, as conventional CHX digluconate solutions and as aqueous suspensions of CHX hexametaphosphate nanoparticles with total CHX concentrations of 1, 2.2 and 5 mM. Soluble CHX release from the treated hydroxyapatite was monitored over a period of 7 days.
  
  
  RESULTS
  A repeated-measures ANOVA with post hoc LSD test indicated that CHX release was 2-3× greater, and sustained for longer, when CHX was delivered as CHX hexametaphosphate nanoparticles than in aqueous solution with 2.2 and 5 mM CHX (P = 0.020 and 0.013, respectively), but there was no statistically significant difference at 1 mM CHX (P = 0.172).
  
  
  CONCLUSIONS
  Chlorhexidine hexametaphosphate nanoparticles increased both the local dose and duration of soluble CHX delivery when applied to hydroxyapatite surfaces. This may provide a means to deliver a sustained dose of CHX with less frequent interventions.
authors.affiliation: Oral Nanoscience, School of Oral and Dental Sciences, University of Bristol, Bristol, UK.
authors.forename: S
authors.initials: S
authors.lastname: Garner
authors.affiliation: Oral Nanoscience, School of Oral and Dental Sciences, University of Bristol, Bristol, UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Barbour
mesh_terms: D000284:Administration, Oral; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use; D002710:Chlorhexidine / Q000008:administration & dosage* / Q000737:chemistry*; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems / Q000379:methods; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry*; D010710:Phosphates
chemical_list: D000891:Anti-Infective Agents, Local; D003692:Delayed-Action Preparations; D010710:Phosphates; C005035:hexametaphosphate; D002710:Chlorhexidine
keywords: chlorhexidine; control; drug delivery; nanoparticles