Abstract
Abstract: :
Purpose: To determine the effect of temperature and light on the rate of degradation of bimatoprost and latanoprost in a patient-use setting. Methods: Open label, parallel-group, multicenter evaluation. Patients with glaucoma or ocular hypertension presently using either bimatoprost (n=31) or latanoprost (n=34) were identified at 2 clinical sites. Medications were dispensed on Day 1 in 2.5 (latanoprost) or 3.0 ml bottles (bimatoprost). Patients continued to use and store their drops as usual and returned between Day 28 and Day 34 for collection of used bottles. Bottles were collected and stored at room temperature and shipped to arrive at a central laboratory between Day 35 and 42. Bottles were tested on approximately the 42nd day after opening. The primary endpoint, the percent of label claim in the bottles at time of testing, was calculated as (concentration in bottle/concentration of the drug indicated on the label)* 100. Results: There was no significant between-group difference in the mean age of the bottles on the test date. The mean age was 43.0 days with bimatoprost and 43.9 days with latanoprost (P=.072). The mean percent of label claim was 103.7% in the bimatoprost bottles and 88.1% in the latanoprost bottles (P<.001). One-hundred percent (31/31) of the bimatoprost bottles contained > 100% of the label claim, compared with 8.8% (3/34) of the latanoprost bottles. The percent of label claim in the latanoprost bottles ranged from 52% to 115%. Conclusions: Latanoprost degrades after the bottle is opened but bimatoprost is consistently stable. These findings suggest that patients are more likely to receive an appropriate dose of bimatoprost than of latanoprost after the bottles have been opened for use and are therefore more likely to achieve maximum IOP lowering.
Keywords: clinical laboratory testing