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EDIT: On re-read, I notice that you didn't say "diaper store," but rather were referring to "medical supply." But this is in the Diaper Talk forum, so...I think we all know what you meant.
)
Curiously, what makes you think that there's a need for a brick-and-mortar diaper store in your area? I would be very skeptical. Diapers are inevitably cheaper online, and people are embarrassed to buy them in person. At the same time, the (often) elderly population who's most in need of diapers is getting increasingly tech-savvy, and will be increasingly disposed to ordering them. Institutions like hospitals and nursing homes are going to order them. ABDLs are scarce, and are used to ordering them. If your prospective customers aren't ordering their diapers already...why not? Do you know? Is it a good reason? Or would you mainly be capitalizing on other people's poor planning, ignorance, occasional emergencies, etc.? That might work for a little while, but...
In short: Do you know who (and why!) your customers are, both now and in the future? Are you truly certain that they exist in the numbers needed to support your stocking products, leasing retail space, and (still) profiting? Advice from a girlfriend really isn't enough. This is stuff for deep thought and research.
And your funding source would probably be a bank, not an angel investor. Investors usually want to hear about new products and inventions, and they expect a percentage of the profits. You're just after a loan with an interest rate. And if you can't successfully pitch your business idea to a bank, consider that it might not be a good idea after all. Or you haven't done enough homework to prove that it is.
Not to be negative or anything.
I get how, to an ABDL, running a diaper business would seem like a great thing. Ask yourself, though: Why isn't somebody already filling the need you describe?