A cream based on water-containing petroleum jelly, which contains 2% erythromycin and 0.1% Clobetasol propionate, is not stable

There are a few problems with this cream.  

1. Although not well water soluble is a hydrolysis of clobetasol propionate by not completely excluding erythromycin (base). So the combination is not favorable  

2. When we look at the structure formula of Clobetasol propionate, there is, to a certain extent, perhaps an amphiophile molecule in which emulgatorische (O/W) properties possess. And then we are with conflicting emulsifiers. All this is and remains a hypothesis

3. Conclusion: Water-Free is perhaps better if watertight