Question
Posted on: March 6 2013We have received the following prescription from a physician: sulfanilamide 0.5 g mercurochroom pdr 1% with hot water up to 10ml magistal ear Drops
The problem posed by this preparation was that Sulfanilamide was crystallized back after cooling down. However, We did not know whether DT had to deal with its solubility or it had to do with an incompatibility between Sulfanilamide and Mercurochroom. This incompatibility was mentioned in the 26th edition of the Martindale (P 1764).
Answer
I suspect that the sulfanilamide possibly dissolves but returns to cool down together with the Mercurochroom, which was exempted from its sodium salt. I only see 1 possibility and this is the use of the sodium salt. I suspect no incompatibility with mercurochroom. After all, the incompatibility, which you mention, concerns the release of Mercurochroom by sulphonamide acid from its sodium salt and hence precipitation. But now we have after sulfonamide compatible with after Mercurochroom.