Drug – bio-affecting and body treating compositions – Effervescent or pressurized fluid containing – Organic pressurized fluid
Reexamination Certificate
2000-01-27
2002-10-29
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Effervescent or pressurized fluid containing
Organic pressurized fluid
C424S046000, C424S047000, C424S078020, C424S078030, C424S489000
Reexamination Certificate
active
06471944
ABSTRACT:
TECHNICAL FIELD
This invention relates to aerosol preparations. More particularly, it relates to powdery aerosol preparations showing improved adhesion of powders and active ingredients on the skin and giving an excellent feel in using.
BACKGROUND ART
Aerosol preparations containing powdery components have been developed to improve the feel in using aerosol products applied onto the surface of the skin and to dry the affected parts or wounds in a moisten state. In these powdery aerosol preparations, various flons were employed as propellants. Since it turned out that flons would cause the environmental disruption, combustible liquefied gases such as liquefied petroleum gas and dimethyl ether have been used as propellants substituting for flons.
However, combustible liquefied gases generally have low boiling points, which brings about some troubles, for example, taking on the latent evaporation heat and thus giving pain on the skin. To avoid the above-described problems, therefore, attempts have been made to spray a powdery aerosol preparation in the form of a fine mist by stopping down the orifice of a valve or a button. In such a case, however, the powder and active ingredient thus sprayed spatter into the atmosphere and, therefore, can be hardly adhered to the skin. Moreover, there arises a fear in safety such as inhalation in using.
Examples of known techniques for enhancing the adhesion of powdery aerosol preparations with the use of these combustible liquefied gases to the skin involve those disclosed in JP-A-60-215092, JP-A-3-118313, JP-A-3-70788, JP-A-3-95289, etc. (the term “JP-A” as used herein means an “unexamined published Japanese patent application”). However, satisfactory adhesion of drugs to the skin cannot be always achieved by these techniques.
DISCLOSURE OF THE INVENTION
As a result of extensive investigation to solve the above-described problems, the present inventors have found out that a very high adhesion rate of a powder and an active ingredient can be obtained by using a combination of a propellant having a low vapor pressure with a straight nozzle button having a large orifice, and that a powdery aerosol preparation, which gives no pain when a low-boiling propellant, etc. is sprayed directly onto the skin and can be dried quickly, can be obtained by using a combination of an aliphatic hydrocarbon having a boiling point of 5 to 40° C. with a lower alcohol. The invention has been completed based on these findings.
Accordingly, the invention provides a powdery aerosol preparation wherein 50 to 90% by weight of a propellant having a vapor pressure at 20° C. of 4.5 kg/cm
2
or less, 5 to 30% by weight of an aliphatic hydrocarbon having a boiling point of 5 to 40° C., 0.5 to 20% by weight of a powdery component and 1 to 20% by weight of a lower alcohol are packed in a container provided with a straight nozzle button having an orifice of 0.7 to 2.0 mm.
The propellant to be used in the invention is one which is selected from propane, n-butane, isobutane and dimethyl ether or a mixture of two or more thereof and has a vapor pressure at 20° C. of 4.5 kg/cm
2
or less. When it is a mixture having a vapor pressure exceeding 4.5 kg/cm
2
, the ratio of propane (boiling point: −40° C.) or dimethyl ether (boiling point: −24° C.) becomes larger and the propellant vaporizes before it reaches the skin. As a result, the powder is atomized and spatters, thereby lowering the adhesion rate to the skin and causing a risk of inhalation.
Examples of the aliphatic hydrocarbon having a boiling point of 5 to 40° C. include n-pentane (boiling point: 36.1° C.), isopentane (boiling point: 27.9° C.) and neopentane (boiling point: 9.5° C.). By using such an aliphatic hydrocarbon, the boiling point of the whole composition can be elevated to a certain level. Thus, the immediate vaporization of the propellant can be prevented and the spattering caused by the atomization of the powder can be regulated. At the same time, the pain on the skin at the spraying can be avoided thereby. It is preferable that the content of the aliphatic hydrocarbon ranges from 5 to 30% by weight of the whole aerosol composition. When the content thereof is smaller than 5% by weight, the above-described effects cannot be fully expressed. On the other hand, it is unfavorable that the content thereof exceeds 30% by weight, since the spray power is weakened due to a decrease in the inner pressure of the aerosol preparation thereby causing clogging with the powder. In this case, there arise additional unfavorable phenomena such as excessively broadened spray pattern and dripping.
The content of the combustible liquefied gas serving as the propellant preferably ranges from 50 to 90% by weight based on the whole aerosol composition. It is unfavorable that the content thereof is smaller than 50% by weight, since the spray power is weakened and thus clogging with the powder occurs in this case. On the other hand, it is also unfavorable that the content thereof exceeds 90%, since the excessively high spray power causes a pain or spattering of the powder.
In the invention, use is further made of a straight nozzle button having an orifice of 0.7 to 2.0 mm. When the orifice is less than 0.7 mm, no favorable preparation can be obtained. This is because the sprayed matter is atomized to thereby extremely lower the adhesion rate to the skin and the powder spatters largely in this case. It is also unfavorable that the orifice exceeds 2.0 mm, since dripping arises in this case.
The valve is not particularly limited, so long as it is a valve commonly employed for powders. The size of the vapor tap orifice scarcely affects the adhesion rate.
In the invention, the powder component is used in order to give an excellent feel in using by elevating the adhesion of the active ingredient to the skin, enhancing the dryness of a moisten part and improving the slipperiness, lubricating action, etc. and, moreover, it is used for facilitating the production of the powdery aerosol preparation. Examples of the powdery component include inorganic powders (silicic anhydride, magnesium silicate, talc, kaolin, mica, zinc oxide, titanium oxide, magnesium oxide, magnesium carbonate, calamine, magnesium aluminate metasilicate, etc.) and organic powders (corn starch, potato starch, nylon powder, polyethylene powder, polystyrene powder, cellulose powder, etc.). Either one of these powders or a mixture of two or more thereof may be employed.
The content of the powdery component ranges from 0.5 to 20% by weight, preferably from 1 to 15% by weight, based on the whole aerosol composition. When its content is smaller than 0.5% by weight, the above-described objects can be hardly achieved. On the other hand, it is unfavorable that the content thereof exceeds 20% by weight, since there arises clogging with the powder in this case.
In the invention, a lower alcohol (ethyl alcohol, isopropyl alcohol, etc.) is used in an amount of from 1 to 20% by weight, preferably from 3 to 15% by weight, based on the whole aerosol composition in order to promote the dissolution of the active ingredient, improve the dispersion stability of the powder in the aerosol composition, improve the spredability of the sprayed powder and active ingredient, etc. When its content is smaller than 1% by weight, the above-described objects can be hardly achieved. On the other hand, it is unfavorable that the content thereof exceeds 20% by weight, since the sprayed matter cannot be quickly dried but becomes sticky in this case.
The powdery aerosol preparation of the invention may further contain, if required, publicly known additives such as silicone oils (methylpolysiloxane, etc.), hydrocarbons (liquid paraffin, suqalane, etc.), higher fatty acid esters (isopropyl myristate, butyl stearate, etc.), vegetable oils (olive oil, castor oil, etc.), animal oils (beeswax, squalene, etc.), nonionic surfactants (sorbitan sesquioleate, polyglycerol fatty acid esters, etc.) and the like.
The active ingredient to be used in the invention is one expected as achieving a therapeutic effect when a
Imaoji Ariko
Suzuki Megumi
Uchiyama Tsuyoshi
Dees Jose′ G.
Dewitty Robert M.
Lorusso & Loud
Taisho Pharmaceutical Co. Ltd.
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