A minoxidil 4% formula without propylene glycol likes.

I don't have a validated formula. I do know the composition of the TMF and which reads

minoxidil 2g
isopropanol 25g
propylene glycol 10g
water up to 50g

I suspect that if you replace the propylene glycol with isopropanol it should succeed. Out of all safety maybe take only 15g isopropanol (so in the total 40g IP) and then water up to 50g.

Two alternative solvents can be: 1. Glycerin, 2. PEG 400.