Delivery of diphenhydramine through an inhalation route
View Patent ↗The present invention relates to the delivery of antihistamines through an inhalation route. Specifically, it relates to aerosols containing diphenhydramine that are used in inhalation therapy. In a composition aspect of the present invention, the aerosol comprises particles comprising at least 5 percent by weight of diphenhydramine. In a method aspect of the present invention, diphenhydramine is delivered to a mammal through an inhalation route. The method comprises: a) heating a composition, wherein the composition comprises at least 5 percent by weight of diphenhydramine, to form a vapor; and, b) allowing the vapor to cool, thereby forming a condensation aerosol comprising particles, which is inhaled by the mammal. In a kit aspect of the present invention, a kit for delivering diphenhydramine through an inhalation route to a mammal is provided which comprises: a) a composition comprising at least 5 percent by weight of diphenhydramine; and, b) a device that forms a diphenhydramine containing aerosol from the composition, for inhalation by the mammal.
1. A composition for delivery of diphenhydramine comprising a condensation aerosol
a) formed by volatizing the diphenhydramine under conditions effective to produce a heated vapor of the diphenhydramine and condensing the heated vapor of the diphenhydramine to form condensation aerosol particles,
b) wherein said condensation aerosol particles are characterized by less than 5% diphenhydramine degradation products, and
c) wherein the aerosol MMAD is less than 3 microns.
2. The composition according to claim 1 , wherein the diphenhydramine is a free base form of diphenhydramine.
3. The composition according to claim 1 , wherein the diphenhydramine degradation product is benzophenone.
4. The composition according to claim 1 , wherein the condensation aerosel particles comprise at least 90 percent by weight of diphenhydramine.
5. A method of producing diphenhydramine in an aerosol form comprising
a) volatilizing diphenhydramine under conditions effective to produce a heated vapor of the diphenhydramine, and
b) during said volatilizing, passing air through the heated vapor to produce aerosol particles of the diphenhydramine comprising less than 5% diphenhydramine degradation products and an aerosol having an MMAD less than 3 μm.
6. The method according to claim 5 , wherein said volatilizing includes heating a thin layer which includes the diphenhydramine and which is on a solid support having the surface texture of a metal foil, to a temperature sufficient to volatilize the diphenhydramine from the thin layer.
7. The method according to claim 5 , wherein the aerosol particles are formed at a rate of greater than 0.5 mg/sec.
8. The method according to claim 5 , wherein the diphenhydramine degradation product is benzophenone.
9. The method according to claim 8 , wherein the aerosol particles comprise at least 90 percent by weight of diphenhydramine.