A liquid aerosol formulation comprising at least one thermally stable
active ingredient selected from the group consisting of buspirone,
buprenorphine, triazolam, cyclobenzaprine, zolpidem, pharmaceutically
acceptable salts and esters thereof and derivatives thereof. The liquid
formulation can include an organic solvent such as propylene glycol and
one or more optional excipients. The active ingredient can be present in
an amount of 0.01 to 5 wt. % and the formulation can be heated to provide
a vapor which forms an aerosol having a mass median aerodynamic diameter
of less than 3 .mu.m.