Implantable biodegradable polymeric device in the treatment of experimental proliferative vitreoretinopathy

Abstract

We investigated the use of a scleral plug of biodegradable polymer implanted at the pars plana to create a controlled drug-delivery system in the vitreous. We evaluated the efficacy of a plug containing doxorubicin hydrochloride to treat experimental proliferative vitreoretinopathy (PVR) in pigmented rabbits. An implantable device on the sclera, which imitates a scleral plug, containing 1% doxorubicin, was prepared with poly(lactic acid) (molecular weight, 20,000). The release of doxorubicin in phosphate-buffered saline was evaluated by spectro-photometry. After pars plana vitrectomy and plug implantation, concentrations of doxorubicin in the vitreous humor of the rabbits were measured by high performance liquid chromatography. The release profiles were evaluated during 5 weeks in vitro and 4 weeks in vivo. Cultured homologous fibroblasts were injected into the vitreous space to induce experimental PVR after gas compression of the vitreous. The scleral plugs were implanted at the pars plana in treatment animals (n = 11). Control rabbits (n = 11) were followed up without implantation after PVR induction. All eyes of the control group developed tractional retinal detachment at day 28, while the incidence of retinal detachment was decreased to 64% in the treated eyes. (P = 0.002). The implantation of the scleral plug effectively inhibited intravitreous proliferation of fibroblasts. This study demonstrated that the scleral plug of biodegradable polymers may have potential as a treatment modality for PVR.