title: Gel properties of hyaluronic acid dermal fillers.
abstract: BACKGROUND
  Most of the hyaluronic acid (HA)-based dermal fillers currently on the market are chemically modified with cross-linkers to improve the mechanical properties and duration in vivo.
  
  
  OBJECTIVE
  To investigate differences in the properties of dermal fillers that can be related to the respective cross-linking and manufacturing methods used.
  
  
  METHODS
  Thirteen commercially available HA fillers were analyzed. Two different measures of gel strength were used: the elastic modulus (G') determined by rheology and a measure of the swelling capacity of the gel (c(min)). The degree of modification was determined using nuclear magnetic resonance spectroscopy, and the cross-linking ratio was determined using size exclusion chromatography coupled with mass spectrometry.
  
  
  RESULTS
  There was a wide variation in gel strength, and the degree of modification varied between 1% and 8% for the HA fillers investigated.
  
  
  CONCLUSIONS
  Both measures of gel strength, G* and c(min), can be used because the results from the two methods are well correlated. No differentiation in filler properties could be seen as a result of manufacturing process used, except that the nonanimal stabilized HA stabilization process resulted in products with high gel strength and a low degree of modification.
authors: Q-Med AB, Uppsala, Sweden. katarina.edsman@galderma.com
authors: Katarina
authors: K
authors: Edsman
authors: Lars I
authors: LI
authors: Nord
authors: Ake
authors: A
authors: Ohrlund
authors: Helena
authors: H
authors: Lärkner
authors: Anne Helander
authors: AH
authors: Kenne
mesh_terms: D002845:Chromatography; D003357:Cosmetic Techniques; D005782:Gels; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D012212:Rheology; D055682:Viscoelastic Substances
chemical_list: D005782:Gels; D055682:Viscoelastic Substances; D006820:Hyaluronic Acid