Sample preparation - erythromycin estolate

Hello everyone!
Does someone have experience with sample preparation of erythromycin estolate DP for LC-MS analysis? We have encountered problem due to estolate which causes foaming of the sample when water based diluent is used.

@Martina thanks for the question. I’m tagging few folks that might be able to help or assist.
@giorgio @Aaron @AmandaGuiraldelli @drhzrd @Hugo @nathananderson @My3sonsMN @Daisuke @shailendra1985 @haaai @davidetartaglione @celine.martin003 @Elodie