Abstract
Abstract: :
Purpose: To investigate the potency of two anti-glaucoma medications, once they have been dispensed to the patient and stored in a variety of possible real-use patient conditions within the United States, including realistic temperature variations and light exposure. Latanoprost 0.005% (X) has labeled storage conditions of: "Protect from light. Opened bottle may be stored at room temperature up to 25 C (77 F) for 6 weeks." Bimatoprost 0.03% (L) is labeled "Store at 15 - 25 C (59 -77 F)." We were interested in the potency of these drugs after simulated real-use storage, as there may be patients who do not adequately follow storage instructions or the 6-week time expiry period for X, or adequately protect product bottles from excessive temperature or direct sunlight. Methods:Multiple lot numbers of both drugs were tested for potency by a high pressure liquid chromatography (HPLC) assay after storage in the dark at either 77 F/25 C room temperature, 104 F/40 C to simulate summer temperatures in many parts of the United States, and 122 F/ 50 C to simulate the bottle being kept at possible summer temperatures such as within a parked car while running errands. All bottles were opened and exposed to air on the initial day of testing. Samples were tested after storage for 42, 55, 84, or 110 days. Additional samples were exposed to simulated sunlight and ultraviolet light corresponding to up to 72 hours of direct sunlight. Results:Averaged potency results, as % of initial value, are shown below. In the dark, L is stable out to 12 weeks at all tested temperatures, while X loses potency at higher storage temperatures. For samples exposed to simulated sunlight, L was stable, while X lost potency quickly. Conclusions:Bimatoprost (L) is stable, when exposed to high storage temperatures or light. Latanoprost (X) is less stable with potency concerns for patients with product stored at temperatures above the label guideline, when exposed to direct sunlight, or with using product remaining past 42 days after dispensing.
Keywords: clinical laboratory testing • drug toxicity/drug effects • clinical (human) or epidemiologic studies: sys