Abstract Background Energy-based devices (EBDs), such as high-intensity focused ultrasound (HIFU), radiofrequency (RF), and microwave, are increasingly used for facial rejuvenation, raising concerns about whether heat exposure may affect the potency of botulinum toxin. Objectives This study investigated the thermal stability of four commercial botulinum toxin type A (BoNT/A) products under conditions simulating EBD-related heat exposure, that includes one liquid formulation (INNOTOX®; hereafter referred to as innoBoNT/A) and three powder formulations: onabotulinumtoxinA (onaBoNT/A, BOTOX®), incobotulinumtoxinA (incoBoNT/A, XEOMIN®), and abobotulinumtoxinA (aboBoNT/A, DYSPORT®). Methods Mouse intraperitoneal LD50 potency assays were performed after exposing reconstituted and liquid formulations to 60 °C for 10–40 minutes. Relative and normalized potency values were compared before and after exposure. Results InnoBoNT/A maintained its potency after 25 minutes of exposure at 60 °C, showing no significant loss of biological activity. In contrast, onaBoNT/A, incoBoNT/A, and aboBoNT/A displayed marked reduction in potency under the same conditions. In particular, onaBoNT/A showed a 32% decrease upon exposure at 60 °C for 25 minutes and a complete loss of measurable potency at when exposed at 60 °C for 40 minutes. Conclusions Among the BoNT/A formulations evaluated, only the liquid-stabilized preparation preserved potency during thermal stress.
Ahn et al. (Wed,) studied this question.