Biodegradable scleral plugs for vitreoretinal drug delivery

Intraocular controlled drug release is one way to facilitate drug efficacy and decrease side effects that occur with systemic administration. Vitreore tinal drug delivery with the biodegradable scleral plug has been investigat ed. The scleral plug, which is made of biodegradable polymers and drugs, ca n be implanted at the pats plana using a simple procedure, and it gradually releases effective doses of drugs with polymer biodegradation for several months. The release profiles of the drugs were dependent on the hind of pol ymers used, their molecular weights, and the amount of drug in the plug. Th e plugs are effective for treating vitreoretinal diseases such as prolifera tive vitreoretinopathy. The implantation site was replaced with connective tissue. Electroretinography and histologic studies revealed little retinal toxicity. This implantable scleral plug was supposed to be advantageous for diseases such as cytomegalovirus retinitis that respond to repeated intrav itreal injections and for vitreoretinal disorders that require vitrectomy. (C) 2001 Elsevier Science B V All rights reserved.