Gasco M R, Gallarate M, Trotta M, Bauchiero L, Gremmo E, Chiappero O
Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, Turin, Italy.
J Pharm Biomed Anal. 1989;7(4):433-9. doi: 10.1016/0731-7085(89)80030-5.
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.
