Abstract: One embodiment of the present invention relates to a method of preparing a concentrated pharmaceutical formulation, comprising the steps of: combining in a container a therapeutic agent, a solvent and at least one pharmaceutically acceptable excipient to give a solution; adding to said solution a seed crystal of said compound to give a heterogeneous mixture; and observing the stability of said heterogeneous mixture.

Abstract: A topical liquid aerosol formulation for accurate metered dose delivery has been developed which includes a concentrate comprising a local anesthetic in a non-alcohol solvent and a hydrofluorocarbon (HFC) propellant. In the preferred embodiment, the concentration of the non-alcohol solvent in the concentrate is between about 75% and 85% by weight of the formulation. In the most preferred embodiment, the non-alcohol solvent is a water-soluble polyol such as ethylene glycol, propylene glycol, glycerol, diethylene glycol, dipropylene glycol, oligoalkylene glycols, liquid polyalkylene glycols, or combinations thereof. In one embodiment, the concentration of the local anesthetic in the concentrate is between about 15% and 25% by weight.