[ghareb]

Hello Everyone
I have a drug containg primary amino groups. This drug is in the form of sulfate salt. I also have dextran containing carboxylate groups in form of sodium salt. When I mix them together, I see little turbidity indicating that a reaction takes place. Now I am trying to find the meachnism of the interaction. I expect the ammonium salt of the drug to react with the carboxylate of the polymer and form sodium sulfate. However, my boss told me that the amine of the drug will not leave the sulfate (strong acid) and go to the carboxylate of the polymer (weak acid). Anybody can help me with this and if there is any reference, I appreciate it.
Thanks

[Borek]

What is pH of solution containing only dextran?

[ghareb]

I do these experiments in phosphate buffer pH 7 so, the pH of the polymer solution is 7.0 and that of the drug sulfate is 6.5 (I adjust to 7).