How do I prepare ear drops with Ciloxan and hydrocortisone acetate in perforated eardrum?

I can hardly connect with the doctor's point of view and prefer to prepare a solution.

I think the replacement of hydrocortisone acetate by following prednisolone phosphate here is not possible as Ciloxan drops contain benzalkonium chloride. Given the solubility of hydrocortisone in water is undoubtedly greater as of hydrocortisone acetate I would use hydrocortisone here. The amount of hydrocortisone acetate should be converted.

I would start with a small preview and dissolve the amount of hydrocortisone in 4 ml propylene glycol. To this solution I would slowly add 5 ml of water under good mixing (= Volume Ciloxan) and see if there is a precipitation. If there is a precipitation then I would add 1 ml of propylene glycol in order to dissolve the precipitation again. If there is no precipitation then the 5 ml can be added completely. Now we have to add 1 ml of water to 10 ml. Again, it checks whether there is a precipitation. If this is the case then it is brought to volume with propylene glycol