Development of a Layer-by-Layer Assembled Film on Hydrogel for Ocular Drug Delivery

Hydrogel is a kind of attractive drug carriers because of its good biocompatibility and transparency. But traditional hydrogel showed some restrictions in its application in ocular drug delivery. A simple surface modification technique based on layer-by-layer (LbL) self-assembled multilayer for ocular drug delivery was developed in this work. Polycarboxymethyl-beta-cyclodextrin (poly(CM-beta-CD))/poly-l-lysine (PLL) multilayer film was designed and constructed for ocular drug delivery, since beta-CD showed good drug delivery property. The properties such as the contact angle and transparency varied a little with the deposition of poly(CM-beta-CD)/PLL multilayer. Orfloxacin and puerarin were loaded into multilayer during the self-assembly procedure by two methods, which were tracked by the largest drug absorbance of UV spectrum. The loaded drug amount by incorporating drugs into poly(CM-beta-CD) solution was larger than that by incorporating drugs into PLL solution. The loaded drug in the multilayer could gradually be released from multilayer in some period either for orfloxacin or for puerarin. The drug release behavior was influenced by drug loading method and pH value of released medium. Moreover, the balanced released drug amount by incorporating drugs into poly(CM-beta-CD) solution is much smaller than that by incorporating drugs into PLL solution.