Comparison of the Degradability of Hyaluronic Acid by Ovine and Recombinant Human Hyaluronidase

BackgroundThe mainstay of treatment for adverse events to hyaluronic acid filler is the use of hyaluronidase (HYAL); however, the dose and dilution are not standardized.

ObjectivesThe objective of this study was to examine differential dilutions and concentrations of HYAL, and to compare the effectiveness of ovine and human HYAL.

MethodsFillers were selected for study based on a variety of rheologic factors. A 0.2-mL dose of product was selected for use based on previous studies. Degradation was assessed by comparing both ovine and recombinant HYAL over a range of concentrations and dilutions.

ResultsIn the 2:1 dilution group, Restylane Lidocaine (Galderma, Lausanne, Switzerland) was degraded by 100 U of ovine HYAL after 50 minutes. No other filler was completely degraded; Restylane Lyft (Galderma) was partially degraded after 1 hour of treatment with 100 U of HYAL. In both the 3:1 and 4:1 dilution groups, Restylane Shaype (Galderma) and Restylane Lyft fillers were most susceptible to degradation, dissolving within 30 minutes with 100 U of recombinant HYAL and within 40 minutes with 100 U of ovine HYAL. Juvéderm and RHA4 fillers were the most resistant, requiring 300 U of HYAL for degradation within 1 hour. Beyond a 3:1 dilution ratio, no further improvement was observed.

ConclusionsThis study demonstrates that 300 U of hyaluronidase is sufficient to degrade 0.2 mL of the most resistant hyaluronic acid fillers within 1 hour. Importantly, a minimum dilution of 3:1 should be used to provide adequate fluid for dissolving filler. Ovine HYAL appears to be just as effective as recombinant HYAL in terms of dissolving product.