Background: The efficacy of botulinum neurotoxin type A after prolonged storage at room temperature is currently unknown. This randomized, double-blinded, split-face study investigated the impact of postreconstitution 25°C storage for 1 week on the clinical efficacy of incobotulinumtoxinA in the treatment of lateral canthus lines.
Patients and methods: Twenty-one participants with at least mild to moderate crow's feet at maximum contraction on the Crow's Feet Grading Scale (CFGS) underwent injection to each lateral canthus area with 10 U of freshly reconstituted and room temperature-stored product and followed for 4 months. Responders were defined as those demonstrating at least a 1-point improvement on their CFGS score.
Results: At each visit (2 weeks and 1, 2, 3, and 4 months), there was no statistical difference in the rate of responders between the fresh and the stored products. In addition, the percentage of responders displaying a 2-point versus a 1-point improvement and response longevity did not statistically differ between both products for the entire 4-month study duration.
Conclusion: Prolonged storage of incobotulinumtoxinA at room temperature does not appear to significantly alter its efficacy or longevity in the treatment of dynamic lateral canthus lines.