Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Chitosan

1,296 views

Published on

Published in: Technology, Business
  • Be the first to comment

Chitosan

  1. 1. 5조 송정환
  2. 2. 1. Introduction 1) Saliva is supersaturated with calcium and phosphate - remineralization at normal pH 2) Action of Fluoride in oral cavity - Reduce the enamel solubility by substitution of hydroxyl group to form (Ca10(PO4)6F2) or (Ca10(PO4)6(OH)2-xFx) - Incorporation of fluoride into dental material i) inhibit the growth of relevant bacteria - ii) recharged with F significant cariostatic benefits - - High [F ] result in CaF2 like deposit : more acid labile
  3. 3. 3) What is Chitosan - copolyme of glucosamine and N-acetyl glucosamine Structure of Chitosan - exhibits moderate to good mucoadhesion - retained on the oral mucosa for several hours in vivo - antibacterial activity4) Use of Chitosan microparticles - local delivery to oral cavity (ex, tetracycline, chorhexidine. etc) - by ionotropic gelation, emulsion polymerisatios forms
  4. 4. 5) The aim of this work 1) spray drying : method for manufacture and characterise chitosan microparticles containing NaF at low cost 2) particle size distribution 3) fluoride loading 4) in vitro fluoride release 5) particle morphology 6) in vitro bioadhesion of discs prepared from compressed chitosan / fluoride microparticles6) Null hypotheses using in vitro models 1) Conc. of glutaraldehyde and chitosan – no affect on particle size, fluoride loading and fluoride release 2) Use of glutaraldehyde – no affect on bioadhesive properties
  5. 5. 2. Materials And Methods 1) Microparticle manufacture a) Chitosan was dissolved in 1.0% acetic acid (40 ml), sealed, stirred overnight b) NaF sln. was prepared in DI water (10 ml) c) b) was added drop wise to a) over period of 60s d) spray drying the 3 sln. using a bench top mini spray drier
  6. 6. 2) Microparticle characterisation 2.1) Particle size distribution – particle sizer 2.2) Enverionmental scanning electron microscypy (ESEM) 2.3) Fluoride analysis – fluoride ion selective electrode 2.4) Determination of total fluoride loading O 2.5) in vitro fluoride release – at 32 C for 360 min 2.6) texture probe analysis – chitosan disc on porcine oesophagi
  7. 7. 3. Result 3.1 Microparticle manufacture - fixed [chitosan]:[fluoride] = 2:1 - two [chitosan]: 1.0 and 2.0 % - increasing chitosan conc. to 2.0 % reduced yield - 2.0 % chitosan only – 19 % yield - 2.0 % chitosan + 0.4 % NaF – 42 % yield
  8. 8. 3.2 Particle size distribution - Increasing [chitosan] effected predictable increase in VMD - D[v, 90] shows greater polydispersity in 2.0 % chitosan - Addition of glutaraldehyde had no significant impact on size distribution (p>0.05)
  9. 9. 3.3 Fluoride loading - Fluoride content and entrapment efficiency were enhanced - when conc. of [chitosan] and [F ] was increased - Addn. of glutaraldehyde had no significant effect on fluoride content and entraptment efficiency
  10. 10. 3.4 Fluoride release profiles 2 - Sample 2 exhibited the greatest cumulative fluoride release with 77.4 % total fluoride released after 360 min.
  11. 11. - Microparticles without glutaraldehyde swelled relatively quickly (sample 1 and 4)- Microparticles with high glutaraldehyde conc. showed minimal swelling due to the high cross-linking density (sample 3 and 6)- For microparticles without or low conc. of glutaraldehyde (0.0010 %) (sample 1 and 4; 2 and 5, respectively), summed the cumulative fluoride release at 360 min was 90 %
  12. 12. - Eeffect of pH on release of fluoride was not significant pH 7.0 pH 4.0 pH 5.5
  13. 13. 3.5 Microparticle morphology - Addition of NaF and glutaraldehyde had minimal effect on the morphology of isolated microparticles
  14. 14. 3.6 Bioadhesion to porcine oesophageal mucosa - Both F max and WOA were dramatically decreased
  15. 15. 4. Discussion 1) Employed low cost spray drying technique to manufacture bioadhesive chitosan/fluoride matrix microparticles 2) No fluoride incoporated chitosan microparticles using spray drying method was investigated 3) Chitosan and fluoride conc. were primary determinant on size distribution 4) Increasing the chitosan conc. resulted in significant increases in particle size
  16. 16. 5) Micro particles could be formulated into an anhydrous dentifrice from which the release of fluoride would be initiated by the addn. of water6) Alternative delivery formats could include aerosolised chitosan/fluoride microparticles7) Based on current aerosol systems, 10 mg of chitosan/fluoride microparticles would introduce up to 630 ㎍ of fluoride
  17. 17. 8) Compressed chitosan/fluoride discs method can be applied9) Incoporation of NaF showed unexpected reduction in bioadhesive ability
  18. 18. 9. Conclusion 1) Bioadhesive chitosan/fluoride microparticles using a low cost spray drying technique was successful 2) Recovered yield were inversely proportional to the viscosity of the original dispersion 3) Isolated chitosan/fluoride microparticles have potential utility as vehicles to enhance fluoride retention and promote controlled fluoride delivery in the oral cavity

×