The safety and efficacy of timolol 0.5% in xanthan gum versus timolol gel forming solution 0.5%

Abstract

Purpose. To evaluate the efficacy and safety of timolol maleate 0.5% gel forming solution (TXE, Merck) versus timolol maleate 0.5% gel forming solution (TXG, Falcon) in primary open-angle glaucoma and ocular hypertension patients. Methods. Following a washout period patients were randomly begun on either TXE or TXG each given once each morning for six weeks (Period 1). Patients then were crossed over to the opposite medicine for Period 2. Following each 6-week treatment period the intraocular pressure was obtained at 08:00 trough and +2 and +8 hours post-dosing. Anterior segment staining and photography were performed to assess surface irritation. Results. Thirty-two patients were enrolled in this study; 28 completed. The diurnal intraocular pressure as well as the 08:00 trough and +2 hour post dosing pressures were statistically equal between groups, although a trend to a lower mean pressure was observed in the TXE (17.9 ± 3.2mmHg) compared to the TXG (18.6 ± 3.4mmHg) group. However, eight hours after dosing the pressure was 17.5 ± 3.2mmHg in the TXE group and 18.9 ± 3.3mmHg in the TXG group (P = 0.0019). Safety was similar between groups, including corneal and conjunctival staining, conjunctival hyperemia graded by anterior segment photography and at the slit lamp, and unsolicited and solicited side effects. Vision recovery after instillation was similar between groups. Conclusion. TXE demonstrates a lower intraocular pressure eight hours after dosing than does TXG, but safety appears similar between products.