A W/O cream with erythromycin breaks after adding nystatin. Erythromycin 4g Nystatin 1.82 g Zn oxide 5g triamcinolone acetonide 0.1 g AVA Creme AD 100 g

When you question: ' Why is nystatin incompatible with Carbomeergel TMF? Is there an alternative in such a way that the gel structure remains intact? ' Open then you will find the structure formula of Nystatin and notice that Nystatin has an acidic function, which reacts with both ZnO and erythromycin. This creates a Zn and a chlorhexidinenystatin salt. I expect the first to behave like a W/O emulsifier But the second one as an O/W emulsifier. As a solution I see two possibilities

1. use water-free AVA
2. Switch to an O/W emulsion cream.

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