Pharmacokinety of intravitreous administration of indomethin

ObjectiveBecause of the recurrent nature of the disease,proliferative vitreoretinopathy(PVR) causes blindness in approximately 10% of patients undergoing retinal re-attachment surgery. Indomethin can prevent PVR.The present study examined the pharmacokinetics of indomethin after intravitreal injection in rabbits.MethodsForty New Zealand rabbits were randomly divided into 10 groups and 8 eyes of 4 animals for each.3mg of indomethin was intravitreously injected in 36 rabbits,and drug did not administrated in 4 rabbits of blank control group.Rabbits of each group were killed at 0.5,1,2,4,8,12,24,48,72 hours following injection of indomethin respectively and the vitreous specimens were obtained immediately.Indomethin concentrations were detected by reversed phase high performance liquid chromatography (RP-HPLC).The main parameters of pharmacokinetics were calculated through DAS pharmacokinetics software.ResultsThe half life for elimination (t_ 1/2 ) of indomethin from vitreous was 7.71 hours.The area under concentration-time curve(AUC) was 3785.59 μg/(ml·h).The clearance (CL) was 0.0015 μg/h.The mass concentration was (347.467±15.671) μg/ml,(305.951±6.608) μg/ml,(233.234±30.910)μg/ml,(228.503±22.080) μg/ml,(172.363±11.486)μg/ml,(113.259±11.738 )μg/ml,(47.743±2.440)μg/ml,(17.457±1.385)μg/mland(6.757 ±0.843 )μg/ml at 0.5,1,2,4,8,12,24,48,72 hours after injection of 30 mg/ml indomethin,respectively.ConclusionThe half life for elimination of indomethin from vitreous is not long.Indomethin can reduce the toxicity of retina and may be a useful pharmacologic tool to control PVR.