Explicit Legal Disclaimer: Do NOT home-compound the topical minoxidil. You (very probably) are NOT a pharmacist. I cannot put here precise instrucions on how to compound topical minoxidil or I may risk legal problems, although unlikely. So, I am listing a few mistakes that people may do, crucial yet important details.
Pitfalls to avoid:
Never weigh any minoxidil powder on top of your sensitive scale directly. Always use something else eg. glassware.
Do not work on porous surfaces or with porous labware, use stainless steel trays and glassware rather than plastic bullshit.
Magnetic stirrers do NOT create enough torque for dissolution of the raw minoxidil powder regardless of the RPM it runs at but good for making a Ethanol-PG-DW mix.
Ethanol takes time to dissolve minoxidil raw powder. With PG-heavy solutions, it is faster but not exponentially so. You are looking to 1 hours at the minimum end for dissolving the topical minoxidil and 2 hours for the maximum end. During the time, you either have to use a stirring rod or an overhead stirrer for continuously stirring the topical minoxidil solution. Since ethanol can only dissolve 29mg/mL of minoxidil while PG can do it at 71mg/mL, ethanol heavy solutions may NOT work. Though, they likely would work, even if mathematically they should not be supposed to dissolve it. It may look as if it is NOT dissolving, do NOT get fooled on the looks and keep stirring at max speed your arms allow you. At 1-1.5hr mark, you will see that the solution is almost perfectly transparent with perhaps some slight white-ish tone. It does NOT end there, after you pour it to the bottle it still has some dissolving left but do NOT worry, as it just needs some time rather than mixing. After 24hrs of preparing topical minoxidil and relocating it to a proper container, it will dissolve almost 100% with crystal-clear transparency.
Minoxidil powder should NOT be utilized in scenarios where it has to be manipulated extensively. There is a good chance it may aerosolize and given that it is a vasodilator, you won’t want it.
A P100 filter full face mask+Nitrile Gloves+Safety Goggles are Necessary. Half face masks are also said to work but I had heard anecdotal accounts on them “leaking” and thus won’t take the risk. If they don’t, you can go with them. Some may say overkill, but better be way overkill than underwhelming.
Ethanol and Propylene Glycol are generally safe for adults, unless you consume a ton of it. They are not powders at the room temperature and do not aerosolize easily to the same extent.
Handle all types of interactions in regards to transferring the raw minoxidil powder inside a glovebox. Avoid handling ethanol inside the glovebox especially if electrical sparks or other elements that may set the ethanol on fire or create an explosion are present. I REPEAT AGAIN, AVOID HANDLING ETHANOL INSIDE A GLOVEBOX.
Aerosolization of raw minoxidil powder is the last thing you would ever want. Have an appropriate air purifier inside with a HEPA-14 filter inside the glovebox and initiate contact with raw minoxidil powder as minimally as possible and handle it slowly and carefully to avoid it mixing with air.
Never use ordinary funnels, I don’t know how powder funnels would work in that regard but ordinary funnels suck for topical minoxidil. Raw minoxidil powder bulks up very easily and is a mess to get through funnels, a very real mess. 4-5 minutes are required at the very least for moving 10-15g of powder, time just spared for it.
Operate by QS logic of pharmacy. Do not pour minoxidil powder to base solution instead pour the solution to minoxidil powder, preferrably on a class A graduated cylinder so you can measure the precise volume that it occupies. eg. 250ml for 250ml solution. Powder funnels may be required beforehand for transferring minoxidil to a 250ml graduated cylinder in the first place though. Plan and operate in a way to avoid aerosolization as much as possible.