Microemulsions as topical delivery vehicles: Ocular administration of timolol

✍ Scribed by M.R. Gasco; M. Gallarate; M. Trotta; L. Bauchiero; E. Gremmo; O. Chiappero

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 512 KB
• Volume: 7
• Category: Article
• ISSN: 0731-7085
• DOI: 10.1016/0731-7085(89)80030-5

✦ Synopsis

The topical administration of timolol as an ion-pair with octanoate was achieved by use of an oil-in-water microemulsion containing lecithin as a surfactant. The microemulsion, a solution of the ion-pair and a solution of timolol alone were instilled in the conjunctival sac of rabbits. A rapid method for the separation and determination of timolol in aqueous humour by HPTLC was used. The bioavailability of timolol from the microemulsion and the ion-pair solution was higher than that obtained from timolol alone. The areas under the curve for timolol in aqueous humour after administration of the microemulsion and the ion-pair solution were 3.5 and 4.2 times higher, respectively, than that observed after the administration of timolol alone.