Pharmaceutical solution aerosol formulations containing...

Drug – bio-affecting and body treating compositions – Effervescent or pressurized fluid containing – Organic pressurized fluid

Reexamination Certificate

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C424S046000

Reexamination Certificate

active

06290930

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to pharmaceutical aerosol formulations containing Budesonide dissolved or solubilized in a fluoroalkane(s) and a cosolvent(s).
BACKGROUND OF THE INVENTION
Chlorohydrocarbon and chlorofluorocarbon propellants used in medical aerosol formulations are generally considered to be environmentally unfriendly. Therefore, these propellants have been largely replaced by hydrofluoroalkanes such as 1,1,1,2 tetrafluoroethane (“HFA-134a”) and 1,1,1,2,3,3,3 heptafluoropropane (“HFA-227ea”)that have been identified as safe for use in pressurized metered dose inhalers.
Medicinal aerosol formulations are generally of the solution or suspension type. Each type is composed of at least the medicament and the propellant. The solution type aerosol formulation contains the medicament dissolved or solubilized in the propellant, or a mixture of propellant and cosolvent. The suspension type aerosol formulation contains the medicament in the form of particles which are dispersed in the propellant. The suspension type aerosol formulations usually contains a surfactant, and can also include a cosolvent. Conventional Budesonide aerosol formulations are of the suspension type.
U.S. Pat. No. 5,736,124 (Akehurst) discloses a suspension type aerosol formulation in which the medicament is in the form of particles dispersed in a cosolvent. The cosolvent is present in an amount less than 5% by weight to avoid dissolving the medicament (column 4, lines 13-24).
Published International Application No. WO 98/05302 discloses a suspension type aerosol formulation in which the medicament is in the form of particles dispersed in a cosolvent. The cosolvent can be present in amount of from 6 to 25% by weight. However, WO 98/05302 teaches that the medicament and cosolvent selected should be such that the medicament is not dissolved in the cosolvent and the particulate shape of the medicament is retained.
The drug Budesonide has proven difficult to formulate in conventional aerosols. There remains, therefore, an important need for aerosol formulations containing Budesonide that remain chemically and physically stable during storage at ambient conditions of temperature and humidity.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide a pressurized metered dose inhaler containing a stable solution formulation of Budesonide which does not require the use of refrigeration.
Another objective of the present invention is to provide a stable solution formulation of Budesonide that is suitable for use as an aerosol, which does not require the use of refrigeration.
The above objectives and other objectives are surprisingly achieved by the following. The present invention provides a novel pressurized metered dose inhaler comprising a container equipped with a metering valve and containing a pressurized solution aerosol formulation formulated from a composition comprising:
Budesonide;
at least one fluoroalkane propellant; and
a cosolvent present in an amount that dissolves or solubilizes the Budesonide in the mixture of cosolvent and propellant.
The present invention also provides a novel solution aerosol formulation adapted for use in a pressurized aerosol container. The aerosol formulation is formulated from a composition comprising:
Budesonide;
at least one fluoroalkane propellant; and
a cosolvent present in an amount that dissolves or solubilizes the Budesonide in the mixture of cosolvent and propellant.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
It has been unexpectedly discovered that chemically and physically stable aerosol formulations of Budesonide can be formulated utilizing unusually high concentrations of cosolvent in which the Budesonide is dissolved or solubilized in the mixture of cosolvent and propellant. Budesonide aerosol formulations can be formed according to the present invention which exhibit stability under elevated temperatures (40° C.), thus requiring no refrigeration.
The amount of Budesonide utilized in the present solution type aerosol formulations is usually from about 0.01 to about 1% by weight, preferably about 0.05 to about 0.5% by weight, and most preferably about 0.3% by weight, based on the total weight of the aerosol formulation. All weight percents herein are based on the total weight of the formulation unless stated otherwise.
Any cosolvent that is suitable for inhalation and capable of dissolving or solubilizing the Budesonide in the mixture of cosolvent and propellant can be used. Examples of suitable cosolvents include alcohols, ethers, hydrocarbons, and perfluorocarbons. Preferably, the cosolvent is a short chain polar alcohol. More preferably, the cosolvent is an aliphatic alcohol having from one to six carbon atoms, such as ethanol or isopropanol. The most preferred cosolvent is ethanol. Examples of suitable hydrocarbons include n-butane, isobutane, pentane, neopentane and isopentanes.
Examples of suitable ethers include dimethyl ether and diethyl ether.
Examples of suitable perfluorocarbons include perfluoropropane, perfluorobutane, perfluorocyclobutane, and perfluoropentane.
When ethanol is utilized as the cosolvent, the cosolvent is usually present in an amount of from about 6% to about 40% by weight, based on the total weight of the aerosol formulation. The ethanol should be present in an amount which fully dissolves or solubilizes the Budesonide in the mixture of ethanol and propellant. Preferably, ethanol is present in amount sufficient to fully maintain the Budesonide in solution at freezing temperatures, such as 0° C. In general, as the temperature is decreased, the solubility of Budesonide in ethanol is decreased. Therefore, an excess of ethanol over the amount required to fully dissolve or solubilize the Budesonide at ambient or room temperature is preferred. In this regard, ethanol is preferably present in an amount of at least 10% by weight, more preferably at least 15% by weight, even more preferably at least 20% by weight, and most preferably at least 25% by weight. Based on the disclosure provided herein, one skilled in the art will recognize that lower concentrations of medicament usually require lower concentrations of cosolvent, and vice versa, in order to form a stable solution. Furthermore, one skilled in the art will recognize that the type of propellant utilized can also affect the amount of ethanol required to fully dissolve or solubilize the Budesonide in the mixture of ethanol and propellant. In general, the greater the polarity of the propellant the less ethanol required to fully dissolve or solubilize the Budesonide. For example, when HFA-134a is utilized as the propellant, the amount of ethanol is preferably from about 10 to about 30% by weight. When HFA-227ea is utilized as the propellant, the amount of ethanol is preferably from about 6 to about 20% by weight.
Any fluoroalkane propellant that is suitable for inhalation can be used. Examples of suitable fluoroalkanes include HFA-134a, HFA-227ea, HFA-125 (pentafluoroethane), HFA-152a (1,1-difluoroethane), and HFA-32 (difluoromethane). Hydrocarbon and/or aliphatic gases may be added to modify propellant characteristics as required. Preferably, the aerosol formulation is substantially free of chlorofluorocarbons. However, if desired chlorofluorocarbons can be utilized. Preferably, the fluoroalkane is 1,1,1,2-tetrafluoroethane (HFA-134a) or 1,1,1,2,3,3,3-heptafluoropropane (HFA-227ea). Most preferably, only a single fluoroalkane is utilized as the propellant.
The propellant is usually present in an amount of from about 60% to about 94% by weight, preferably from about 70 to about 90% by weight, based on the total weight of the aerosol formulation.
A preferred aerosol formulation comprises HFA-134a or HFA-227ea in an amount less than about 90% by weight, ethanol in an amount of at least about 10% by weight, and Budesonide in an amount of from about 0.05 to about 0.5% by weight. A particularly preferred aerosol formulation comprises about 86% by weight of HFA-227ea, about 14% by weight of ethanol, and about 0.3% by weight of Budesonide. Another part

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