Comprehensive Analysis of Free BDPE Content in Commercial Hyaluronic Acid Fillers: Implications for Safety Assessment and Regulatory Standards.

Industry claims regarding complete cross-linker removal may fail to account for the persistence of BDPE species. The substantial inter-product variability observed in this study suggests inadequate process control among manufacturers. Given the structural similarity of BDPE to known sensitizers and the direct dermal injection route that circumvents the skin barrier, free BDPE should be designated a critical quality attribute with defined acceptance limits. These findings suggest that BDPE can be reduced to concentrations below 2.5 ppm, supporting the need for stricter manufacturing standards.