We are currently working on a photopolymerized hydrogel using riboflavin as a photoinitiator.

The riboflavin we have is not soluble in water and needs DMSO to make it soluble. There are concerns using DMSO on cytotoxicity.

Riboflavin monophosphate sodium salt is water soluble.

Is there a simple way to convert Riboflavin to its monophosphate sodium salt?