LAUSR

Abstract To manage glaucoma, timolol is currently delivered via eye drop solution in high doses due to poor ocular bioavailability. The silicone contact lenses can be used to control the release of timolol by conventional soaking technology without changing or altering the swelling and optical transmittance of the contact lens. However, the soaking method showed limitations of low timolol uptake and high-burst release. In this research work, we have investigated the influence of microemulsion on timolol loading from the soaking solution and its ability to control the drug release kinetics. The contact lenses were soaked in the timolol-microemulsion soaking solution (TB-ME-SM) and compared with the timolol-soaking solution (TB-SM) without microemulsion. The loading of timolol laden-microemulsion in the contact lenses did not alter the swelling and transmittance properties. The two fold improvement in the timolol loading was noted from the TB-ME-SM soaking solution in comparison to TB-SM solution. The flux report showed improvement in the release rate profiles of TB-ME-SM lenses (up to 48–96 h) in comparison to TB-SM lenses (up to 24–36 h). The rabbit tear fluid data of TB-ME-SM lenses showed improvement in the timolol retention time in comparison to TB-SM lenses and eye drop solution. The efficacy study in the rabbit model showed a peak and valley profile with eye drop therapy, while TB-ME-SM-2 contact lenses showed prolong reduction in intra ocular pressure for 96 h. The study demonstrates the potential of microemulsion to improve the uptake of timolol and control release kinetics without altering the swelling and transmittance of the contact lens. Graphical Abstract