| 摘要 |
Aqueous anaesthetic solutions, prepared by adding carbon dioxide to an aqueous suspension of a local anaesthetic of the basically substituted acid amide type, e.g. lidocaine, until the anaesthetic base is dissolved, are applied from pressure resistant dispensers in which the propellant may be a mixture of chlorofluorohydrocarbons.ALSO:Aqueous solutions of local anaesthetics of the basically substituted acid amide type are prepared by introducing carbon dioxide, in an amount in excess over that stoichiometrically required for carbonate salt formation, into an aqueous suspension of the anaesthetic, at a temperature not exceeding ambient temperature, until the anaesthetic base has been dissolved. In a modification, an acid addition salt of the anaesthetic base is used together with a water-soluble, acid-neutralizing agent, e.g. sodium bicarbonate, sodium carbonate or sodium hydroxide, in an amount equimolecular to the acid moiety of the addition salt, and carbon dioxide is then introduced to dissolve the liberated base. Anaesthetics specified are lidocaine, mepivacaine, a -(n-propylamino)-propionyl-toluide-(2), (n-butyl-amino)-acetyl-2-methyl-6-chloroanilide and diethylamino-acetyl-2, 6-dimethyl-4-butoxyanilide. The solutions may be used in vials, ampoules or pressure resistant dispensers and may be incorporated into jellies, ointments and creams. When used in pressurised form, the propellant may be excess carbon dioxide, nitrogen or a chloro-fluorohydrocarbon. |
