Hylans (hyaluronan derivatives) retain the biological compatibility of the natural hyaluronan and have enhanced rheological properties which expands their utility in medical applications. Hylan materials (hylan A fluid, hylan B gel) were evaluated in a variety of tissue compartments for local and systemic tissue reaction (gross and microscopic), residence time and overall behavior in vivo. Hylan material was implanted into the subcutaneous, intradermal, submucosal, intramuscular, eye (vitreus, anterior chamber, trabecular meshwork), and neural (sciatic nerve) tissues at volumes ranging from 0.50 ml/kg to 20 ml/kg (2.5 mg/kg to 100 mg/kg). There was no difference in tissue response to hylan implants at the various ‘doses’ evaluated; all samples tested were observed to be biocompatible and did not elicit significant tissue response. Therefore, tissue reaction of hylan implants was not dependent on dose or concentration of hylan administered, since implantation of small amounts resulted in the same response as implantation of large amounts of material. In one of the most sensitive tests of biocompatibility, hylan was found to have no adverse effect on nerve regeneration (severed sciatic nerves in rat), and the results indicated that hylan materials “regeneration-friendly” environment for peripheral nerve growth as commatpearriaelds tpor othveid BedS Sa controls.

Hylan materials provide biologically and physically compatible intercellular matrices which are useful in a variety of medical applications, including use as viscosurgical and viscoprotective tools (to maintain space, separate and protect tissues) and as viscosupplementation devices and implants.