Latanoprost Storage Requirements
Latanoprost ophthalmic solution remains stable and effective when stored at room temperature (up to 25°C/77°F) for 4-6 weeks after opening, eliminating the need for refrigeration during patient use. 1, 2
Storage Before Opening (Unopened Bottles)
- Refrigeration at 2°C-8°C (36°F-46°F) is recommended for unopened bottles to maintain optimal long-term stability until dispensing. 3
- Unopened bottles should be protected from light exposure, as ultraviolet B radiation causes rapid degradation of latanoprost. 3
Storage After Opening (In-Use Bottles)
- Room temperature storage (up to 25°C/77°F) is acceptable and effective for 4-6 weeks after opening, which covers the typical duration of patient use. 1, 2
- In a clinical study of 89 patients storing latanoprost at room temperatures ranging from 70-95°F during daytime, 94% of bottles maintained concentrations within 90-110% of the labeled amount after 4-6 weeks of use. 1
- A controlled trial demonstrated that latanoprost stored at 30°C (86°F) for 4 weeks after opening achieved statistically equivalent IOP reduction compared to refrigerated storage at 4°C, with no difference in safety profile. 2
Temperature Stability Thresholds
- Latanoprost remains fully stable at 4°C and 25°C for at least 30 days. 3
- At 50°C (122°F), the time for 10% degradation (t90) is 8.25 days, indicating significant heat sensitivity at extreme temperatures. 3
- At 70°C (158°F), degradation accelerates dramatically with t90 of only 1.32 days. 3
Practical Clinical Recommendations
- Patients should be instructed that refrigeration after opening is optional, not mandatory, as room temperature storage maintains therapeutic efficacy throughout the typical 4-6 week usage period. 1, 2
- Bottles should be stored away from direct sunlight and heat sources, as UV-B radiation and temperatures exceeding 30°C accelerate degradation. 3
- The bottle should be discarded after 4-6 weeks of use regardless of storage temperature, as this represents the validated stability window. 1
Common Pitfalls to Avoid
- Do not assume refrigeration is required after opening—this outdated recommendation creates unnecessary patient burden and may reduce adherence when refrigeration is unavailable. 1, 2
- Avoid storage in locations exceeding 30°C (86°F), such as car glove compartments or windowsills, as temperatures above 50°C cause measurable degradation within days. 3
- Never expose bottles to direct sunlight, as UV-B radiation degrades latanoprost more rapidly than heat alone. 3