Can I Make My Own Topical Finasteride?

I have finasteride 5mg pills. I crushed up the pill until it was very fine powder. I put it in an empty bottle of Minoxidil. I added 5ml of Minoxidil. Shook up the contents My intention is to shake up this mixture prior to applying and apply 1ML of this mixture a day via the Minox dropper. Thus this mixture should last 5 days Am i missing something here or is this sound?