Metronidazole 500mg, erythromycin 2g, O/W cream ad 50g. How is this cream best prepared?

For this I can recommend the formulation of the TMF in the making that will use an unbuffered CETOMACROGOLCR è me with the following composition:

cetostearyl alcohol 2.4 G
Cetomacrogol 1000 0.6 g
decyloleate ( Cetiol) 6g
propylene glycol 3g
sorbic acid 0.2 g
purified water up to 100g