I think it depends on the lipophilicity (fat solubility) of the compound... from what I recall fentanyl as freebase (nonpolar) actually has high bioavailibility, LSD tartrate (polar) in DMSO doesn't.
With a predicted LogP of about 1.6 vs fentanyl's logP of 4.0, that works out that salvinorin A is about 300 times less fat soluble. So I guess it could work, but you'd need to use a lot of salvia.