Sustained ocular delivery of tilisolol to rabbits after topical administration or intravitreal injection of lipophilic prodrug incorporated in liposomes

To improve the retention time of tilisolol in the precorneal area or vitreo us body we prepared, liposomes incorporating the O-palmitoyl prodrug of til isolol. O-Palmitoyl tilisolol was completely incorporated in the liposomes. After topical administration of O-palmitoyl tilisolol liposomes to the rab bit eye, O-palmitoyl tilisolol rapidly disappeared from the tear fluid. The inclusion of 2 % carmellose sodium slightly prolonged the retention of O-p almitoyl tillsolol in the tear fluid. After intravitreal injection of O-pal mitoyl tilisolol liposomes, there was a relatively prolonged retention of O -palmitoyl tilisolol in the vitreous body. At 24 and 48 h after intravitrea l injection of O-palmitoyl tilisolol liposomes, the tilisolol concentration in the vitreous body was significantly higher compared with the concentrat ion after intravitreal injection of tilisolol liposomes.