Sensitivity of Hyaluronic Acid Fillers to Hyaluronidase: An in vitro Analysis

Objective: The purpose of this study was to provide qualitative information on the in vitro dissolution of hyaluronic acid (HA) fillers upon exposure to hyaluronidase and to determine whether in vitro sensitivity of fillers relates to clinical findings in patients treated with hyaluronidase to manage complications of HA filler placement. Methods: The authors undertook an in vitro study to evaluate how 6 types of HA fillers respond to hyaluronidase exposure. The findings were compared to outcomes in 3 clinical cases in which hyaluronidase was given to manage adverse outcomes of HA injection. Results: The fillers responded differently to the same dose of hyaluronidase. Fillers with a higher concentration of HA or a greater degree of crosslinking generally were more resistant to enzymatic dissolution. Clinical findings were consistent with in vitro results. Conclusion: The sensitivities of HA fillers to hyaluronidase in vitro were consistent with clinical findings.