Question
Posted on: March 6 2013Please help in connection with a problem magistal preparation: ZnO 10% hydrocortisone acetate 1% in AVA
The ointment base is recommended by the TMF. This is the same problem that the buffered CETOMACROGOLCR è me (nl stability problem). Is it enough to provide sour pH? But how? Lactic acid? Citric acid? Is Citric acid not incompatiebel with hydrocortisone acetate? Lactic acid? Can that be added to a postprepared W/O base to make pH 5? Or is it better to add ZnO and hydrocortisone acetate to another W/O base like Cremor sorbatis PMF?
Answer
The situation is similar; Alcalically reacting water will not be conducive to the stability of hydrocortisone acetate. Buffering or acidifying becomes a problem due to the presence of ZnO that will give the water an of pH given that there will be a saturated solution. I am afraid that all of your good proposals will not be enough to remedy the need to add mass quantities. The different acids react with ZnO for the formation of BV zncitrate...
There are two possibilities
- omit either ZnO; maybe not the desire of the dermatologist;
- or hydrocortisone; I note that in the commentated drug directory A number of CR è Mes with hydrocortisone are prevented.