Blind multicenter study of the efficacy and safety of injections of a commercial preparation of botulinum toxin type A reconstituted up to 15 days before injection.

Background: It is recommended that attention be given to the shelf life of botulinum toxin type A (BT-A) after its reconstitution.

Objective: To assess the efficacy and safety of 500 U of BT-A after reconstitution up to 15 days after injection.

Material And Methods: BT-A vials were diluted 15 days, 8 days, and 8 hours before injection. One hundred five volunteers were randomized to one of three treatment groups, according to dilution dates. They were evaluated at baseline and 28, 56, 84, and 112 days after treatment. At each visit, the investigator and the volunteer evaluated the motility of the treated area using a 4-point qualitative scale. Five independent specialists, who scored the motility of the treated area on the same scale, blind analyzed photographs taken at each visit. The reconstituted vials of BT-A were stored and analyzed before and after the study.

Results: No significant difference was shown between the groups. No evidence of contamination was found in the BT-A vials.

Conclusion: The results confirm the possibility of injecting 500 U of BT-A up to 15 days after its reconstitution safely and without loss of efficacy.