title: In vitro uptake and release of natamycin Dex-b-PLA nanoparticles from model contact lens materials.
abstract: OBJECTIVE
  To evaluate the uptake and release of the antifungal agent natamycin encapsulated within poly(D,L-lactide)-dextran nanoparticles (Dex-b-PLA NPs) from model contact lens (CL) materials.
  
  
  METHODS
  Six model CL materials (gel 1:poly(hydroxyethyl methacrylate, pHEMA); gel 2:85% pHEMA: 15% [Tris(trimethylsiloxy)silyl]-propyl methacrylate (TRIS); gel 3: 75% pHEMA: 25% TRIS; gel 4: 85% N,N dimethylacrylamide (DMAA): 15% TRIS; gel 5:75% DMAA: 25% TRIS; and gel 6: DMAA) were prepared using a photoinitiation procedure. The gels were incubated in: (1) natamycin dissolved in deionized (DI) water and (2) natamycin encapsulated within Dex-b-PLA NPs in dimethylsulfoxide/DI water. Natamycin release from these materials was monitored using UV-visible spectrophotometry at 304 nm over 7 d.
  
  
  RESULTS
  Natamycin uptake by all model CL materials increased between 1 and 7 d (p < 0.001). The uptake of natamycin-NPs was higher than the uptake of the drug alone in DI water (p < 0.05). Drug release was higher in materials containing DMAA than pHEMA (p < 0.05). All gels loaded with natamycin-NPs also released more drug compared to gels soaked with natamycin in DI water (p < 0.001). After 1 h, CL materials loaded with natamycin alone released 28-82% of the total drug release. With the exception of gel 6, this burst released was reduced to 21-54% for CL materials loaded with natamycin-NPs.
  
  
  CONCLUSIONS
  Model CL materials loaded with natamycin-Dex-b-PLA NPs were able to release natamycin for up to 12 h under infinite sink conditions. DMAA-TRIS materials may be more suitable for drug delivery of natamycin due to the higher drug release observed with these materials.
authors.affiliation: a Centre for Contact Lens Research, School of Optometry and Vision Science , University of Waterloo , 200 University Avenue West, Waterloo , ON , N2L 3G1 , Canada .
authors.forename: Chau-Minh
authors.initials: CM
authors.lastname: Phan
authors.forename: Lakshman
authors.initials: L
authors.lastname: Subbaraman
authors.forename: Shengyan
authors.initials: S
authors.lastname: Liu
authors.forename: Frank
authors.initials: F
authors.lastname: Gu
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry*; D003261:Contact Lenses; D003911:Dextrans / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D010866:Natamycin / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry
chemical_list: D000935:Antifungal Agents; D003911:Dextrans; D004337:Drug Carriers; D020100:Hydrogels; D011091:Polyesters; D012828:Silicones; C033616:poly(lactide); D010866:Natamycin