How to make: erythromycin base 2% hydrocortisone acetate 1% isopropanol 70 ° ad 200ml

I suspect that erythromycin is soluble in isopropanol 70% and this analogy with the erythromycin preparations from the TMF. So it probably beats hydrocortisone acetate. Given the concentration of isopropanol, it is still difficult to increase, we are preparing a suspension in which we use Hydroxypropylcellulose 400 as a viscosities increasing substance 1 à 2%.