SEC determination of cross-link efficiency in hyaluronan fillers

► NMR of linear and cross-linked HA permitted the total linked BDDE quantification. ► Alkaline hydrolysis increased the aqueous solubilization of cross-linked HA. ► Kinetical hydrolysis constants are comparable on linear and cross-linked HA. ► The efficient cross-links were determined as very low by SEC analysis. ► Elastic modulus increases with the cross-link degree.