Hyaluronic acid-based nanocomposite hydrogels for ocular drug delivery applications.

Hyaluronic acid (HA) is a widely investigated biomaterial for many therapeutic applications owing to its unique properties of biocompatibility, biodegradation, and viscoelasticity. HA being a natural component of eye tissue with significant role in wound healing is a natural choice as a carrier for ocular drug delivery, provided the incorporated drugs are released in a sustained manner. However, localized sustained release of drugs inside eye has been difficult to achieve because of the inability to retain carriers for long periods in the eye. Using noncrosslinked (soluble) HA offers limited control over site retention of drugs. In order to obtain prolonged sustained delivery, two HA-based composite hydrogels incorporating nanocarriers, have been synthesized and characterized for swelling, rheology, degradation, and in vitro release of latanoprost, a drug used to reduce intraocular pressure. The HA is first chemically modified, mixed with drug-loaded liposomes, and then crosslinked to obtain nanocomposite hydrogels. In vitro release study shows longer sustained release of latanoprost from composite hydrogels as compared to liposomes or hydrogels alone indicating additional resistance to drug diffusion because of the incorporation of liposomes inside the hydrogels. It is believed that these nanocomposite hydrogels, with controlled degradation properties and sustained release, could serve as potential drug delivery systems for many ocular diseases.