| 摘要 |
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. In the preferred embodiment, the hydrofluorocarbon propellant is 1,1,1,2-tetrafluoroethane 1,1,1,2,3,3,3-heptafluoropropane or combinations thereof, in a concentration between about 35% and 65% by weight of the final formulation, more preferably between about 45% and 55% by weight of the final formulation. A particularly preferred formulation includes benzocaine, tetracaine, and butylaminobenzoate, wherein the concentration of benzocaine in the concentrate is 14% by weight, the concentration of tetracaine in the concentrate is 2% by weight, and the concentration of butylaminobenzoate in the concentrate is 2% by weight. It has been found that the formulation is more stable in the substantial absence of oxygen. The formulation is preferably administered using a metered dose device for release of a controlled amount of the local anesthetic.
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