Solvent‐free biodegradable scleral plugs providing sustained release of vancomycin, amikacin, and dexamethasone—An in vivo study

Abstract

Delivering effective drugs at sufficiently high concentrations to the area of infection is a standard treatment for infectious disease, such as endophthalmitis. This is currently done by empirical trans pars plana intravitreal injection of both antibiotics directed against gram-positive and gram-negative microorganisms and steroids. However, injections by needles repeatedly may increase the risks of intraocular infection and hemorrhage, as well as retinal detachment. This article explores the alternative of using biodegradable polymers as scleral plugs for a long-term drug release in vivo. To manufacture plugs, poly(lactide-glycolide) copolymers were first mixed with vancomycin, amikacin, and dexamethasone. The mixture was compressed and sintered at 55 degrees C to form scleral plugs 1.4 mm in diameter. Biodegradable scleral plugs released high concentrations of antibiotics (well above the minimum inhibitory concentrations, MIC) and steroids in vivo for the period of time needed to treat intraocular infection. In addition, no major complications such as infectious or sterile endophthalmitis, retinal detachment, ocular phthisis, or uvea protrusion at sclerotomy site were observed throughout the experiment. The sclerotomy wound healed after total degradation of the scleral implants without leakage or local necrosis. Antibiotic/steroid-impregnated biodegradable scleral plugs may have a potential role in the treatment of various intraocular infections.

Bacterial endophthalmitis in the age of outpatient intravitreal therapies and cataract surgeries: Host–microbe interactions in intraocular infection

“…2). The use of biodegradable polymers mixed with vancomycin, amikacin, and dexamethasone as scleral plugs for treatment of endophthalmitis was found to deliver high concentrations of drugs in vivo in experimental endophthalmitis over an extended period of time without any major complications (Peng et al 2010). …”

Antiinflammatory effect of low-level laser therapy on Staphylococcus epidermidis endophthalmitis in rabbits

“…Bacterial invasion of the body causes two pathological processes, which include toxic effects of bacterial virulence factors on the host and host defence [12]. Many studies have shown that bacteria can secrete a variety of toxic substances and that bacterial cell wall components have toxic effects on intraocular tissue.…”

“…Elimination of eye tissue damage and improving the final visual outcome in endophthalmitis is challenging. Intravitreal injection of antibiotics is necessary to treat endophthalmitis, and inhibiting the inflammatory response within the eye is also very important [12]. Although the current clinically used antiinflammatory is dexamethasone, controversy remains regarding the use of dexamethasone in experimental models and in clinical treatment.…”

Prophylaxis Against Postoperative Endophthalmitis in Cataract Surgery

“…They have the theoretical advantage of overcoming medication non-adherence, as well as providing a barrier to prevent microbial seeding while the wound heals. 89 Further research in developing drug delivery systems that are safe and effective can potentially overcome the limitation of patient adherence and further reduce the risk of postoperative endophthalmitis. 83 Small clinical studies suggest that collagen shield use after extracapsular cataract surgery is safe, 84,85 and may reduce the risk of postoperative endophthalmitis in phacoemulsification cataract surgery with clear corneal wounds.…”