Purpose: The purpose of the study was to determine the concentrations of Flarex® and Lotemax® when shaken and not shaken. Many patients fail to shake or inappropriately shake suspensions of corticosteroids before instillation as directed. This study was designed to help determine what concentration of corticosteroid these patients are receiving. In addition, independent confirmation of loteprednol etabonate ophthalmic gel dose uniformity was determined and compared as a possible alternative.
Methods: Drug concentrations of shaken versus unshaken Flarex and Lotemax were determined over a 20-day simulated tapered course in our institutional laboratory. Collected samples were analyzed by reversed-phase high-performance liquid chromatography with photodiode array detection at 240 nm.
Results: Flarex had a mean concentration of 93.7% of the declared concentration when shaken and 7.25% when not shaken. The difference between these groups was statistically significant (P = 0.0001). Lotemax had a mean concentration of 96.74% of the declared concentration when shaken and a mean concentration of 98.97% when not shaken. The difference between these groups was not statistically significant (P = 0.194).
Conclusions: Flarex maintains dose uniformity when shaken. When not shaken, it has poor dose uniformity. Lotemax was consistent whether shaken or not in our study and can be considered to eliminate the variability of poor patient compliance with shaking. The manufacturers of both drugs recommend shaking before application.
Keywords: dose uniformity; flourometholone acetate; loteprednol etabonate; ophthalmic formulation; simulated dosing.