French dressing does, but it takes
a good shaking to make them co-exist.
In 2003, Pashley at ANU, Canberra
reported that degassing the fluids made
it easy to form a stable emulsion of oil
and water.
Eastoe at UBristol,UK, found repeated
freeze thaw cycles would work instead
of degassing in 2004.
The theory is surprizingly fuzzy for this
effect: on the one hand it sounds like a
Science Fair experiment: on the other,
finding water bases for injectable
oil-miscible drugs is potentially very,
very interesting.
[NewScientist, 26Mar2005, p27]
On an unrelated note, there is a solvent called DMSO,
dimethyl sulphoxide, which is used as a drug carrier,
for its unusual property of readily transporting
materials through the skin. This is used in veterinary
practice and animal husbandry. Users are warned to
wear gloves when handling DMSO which contains
dissolved components. There are folk tales of
self-medicators using it for rheumatic joints...