Ocular delivery of acetylsalicylic acid by repetitive coulomb-controlled iontophoresis

To investigate the potential of transscleral coulomb-controlled iontophoresis (CCI) for repetitive delivery of acetylsalicylic acid (ASA) into the eye, a total of 50 rabbits was included in this study. Fourteen animals received serial CCI treatment. Fourteen animals underwent CCI with either ASA or balanced salt solution (BSS) for at least 6 days at 24- and 48-hour intervals. Eighteen animals received a single CCI application, while 18 animals were injected with 15 mg ASA/kg body weight intravenously. HPLC analysis was performed to determine the levels of salicylic acid (SA) in ocular tissues. Apart from clinical follow-up, 2 rabbits in the ASA and BSS groups were examined by electroretinography, and 2 animals were examined histologically. Though high concentrations of SA were measured, no alterations were observed clinically, histologically and electrophysiologically. Repetitive CCI demonstrated its potential as a topical drug delivery system for ASA into the eye. This transscleral delivery of ASA resulted in significant and sustained intraocular concentrations of SA without side effects. Iontophoresis may be advantageous in clinical administration maintaining therapeutic levels of ASA while avoiding adverse effects associated with the systemic administration of nonsteroidal anti-inflammatory drugs

Safety and feasibility of a novel intravitreal tamponade using a silicone oil/acetyl-salicylic acid suspension for proliferative vitreoretinopathy: first results of the Austrian Clinical Multicenter Study

The safety and efficacy of a new surgical method of intravitreal tamponade using silicone oil suspended with aspirin (acetylsalicylic acid) was investigated for the treatment of proliferative vitreoretinopathy. The study was designed as a prospective, randomized, controlled, double-blind multicenter study. A total of 29 patients were included; 15 patients were treated with the silicone oil suspended with aspirin, and 14 patients represented the control group receiving only silicone oil. A standard three-port pars plana vitrectomy was performed in 29 eyes of 29 patients. In cases in which the natural lens was present, simultaneous phacoemulsification was required. The control group received as standard therapy a vitreous tamponade with pure 5000 mPas silicone oil and the treatment group received silicone oil containing 0.2 mg/ml aspirin (AS SiO). At 6 months after surgery, the tamponade was removed from all eyes. The main outcome measure was the incidence of retinal redetachment requiring reoperation. Secondary outcome measures were visual acuity and ophthalmic examination results. The rate of redetachment, defined as the primary outcome parameter, was the same for both groups. The AS SiO was well tolerated and remained clear during the 6-month study period. Clinical examination revealed no signs of local or systemic adverse effects. The visual acuities were well matched before inclusion in the study and there were no significant differences during the follow-up period and in the final visual outcome between the two groups. Aspirin delivery by intravitreal silicone oil in the human eye is safe and also may provide a delivery vehicle for other antiproliferative agents to the posterior pole

Pharmacokinetics of Systemic Versus Focal Carboplatin Chemotherapy in the Rabbit Eye: Possible Implication in the Treatment of Retinoblastoma

PURPOSE. To characterize the pharmacology and toxicity of intravenous versus focal carboplatin delivery in the rabbit eye. METHODS. Pharmacological distribution of carboplatin was examined in New Zealand White Rabbits after a single intravenous infusion of carboplatin (18.7 mg/kg of body weight), a single subconjunctival carboplatin injection (5.0 mg/400 L), or a single application of carboplatin delivered by Coulombcontrolled iontophoresis (CCI; 14 mg/mL carboplatin, 5.0 mA/ cm 2 , 20 minutes). After each treatment, animals were euthanatized, and the eyes analyzed at 1, 2, 6, or 24 hours by atomic absorption spectroscopy to determine carboplatin concentration in ocular structures. Potential toxicity of focally delivered carboplatin was assessed by histology after six cycles of 5.0 mg carboplatin delivered by subconjunctival injection or six transscleral carboplatin CCI applications at 72-hour intervals (14.0 mg/mL, 20 minutes at 2.5 mA). RESULTS. Determination of concentrations through atomic absorption spectroscopy in the retina, choroid, vitreous humor, and optic nerve after subconjunctival injection or iontophoretic carboplatin delivery revealed significantly higher levels than those achieved with intravenous administration. Carboplatin concentrations in the blood plasma were found to be significantly higher after intravenous delivery than after focal delivery by subconjunctival injection or CCI. No evidence of ocular toxicity was detected after focally delivered Carboplatin. CONCLUSIONS. Focal administration of carboplatin using subconjunctival or noninvasive CCI safely and effectively transmits this chemotherapeutic drug into the target tissues of the retina, choroid, vitreous, and optic nerve. These results suggest that focal carboplatin delivery may effectively increase intraorbital carboplatin concentrations while decreasing systemic exposure to this cytotoxic drug. (Invest Ophthalmol Vis Sci