title: Intra-articular Duration of Durolane™ after Single Injection into the Rabbit Knee.
abstract: OBJECTIVE
  The aim of the present study was to investigate the intra-articular duration of Durolane™ in a rabbit model to allow comparison between Durolane™ residence time and data reported for other hyaluronic acid products as well as native hyaluronic acid.
  
  
  METHODS
  (14)C-labeled Durolane™ was manufactured by labeling the cross-linker used for stabilization. A single injection of approximately 0.3 mL (14)C-labeled Durolane™ was administered intra-articularly in both knee joints of male New Zealand White rabbits. At days 1, 2, 3, 7, 28, 60, 96, and 120 after injection, the knee joints of 4 animals were collected, and the radioactivity of the remaining gel was measured. The obtained data were fitted by exponential models to calculate the half-life of the gel. Two additional rabbits were used for histology of the joint 127 days after the injection.
  
  
  RESULTS
  The elimination of (14)C-labeled Durolane™ followed first-order kinetics with an apparent half-life of approximately 32 days. Histology showed no morphological changes in the knee joints.
  
  
  CONCLUSIONS
  This study shows that Durolane™ has a half-life of 32 days in the rabbit knee joint, which is much longer compared to literature data on hyaluronic acid and other modified hyaluronic acid products.
authors.affiliation: Q-Med AB, Uppsala, Sweden.
authors.forename: Katarina
authors.initials: K
authors.lastname: Edsman
authors.affiliation: Q-Med AB, Uppsala, Sweden.
authors.forename: Roland
authors.initials: R
authors.lastname: Hjelm
authors.affiliation: Q-Med AB, Uppsala, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Lärkner
authors.affiliation: Q-Med AB, Uppsala, Sweden.
authors.forename: Lars I
authors.initials: LI
authors.lastname: Nord
authors.affiliation: Q-Med AB, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Karlsson
authors.affiliation: Q-Med AB, Uppsala, Sweden.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Wiebensjö
authors.affiliation: Visionar Preclinical AB, Uppsala, Sweden.
authors.forename: A Urban
authors.initials: AU
authors.lastname: Höglund
authors.affiliation: Q-Med AB, Uppsala, Sweden.
authors.forename: Anne Helander
authors.initials: AH
authors.lastname: Kenne
authors.affiliation: Q-Med AB, Uppsala, Sweden ; PledPharma AB, Stockholm, Sweden.
authors.forename: Jacques
authors.initials: J
authors.lastname: Näsström
keywords: Durolane™; duration; hyaluronic acid; intra-articular; osteoarthritis