MXPA97001376A - Composition of antitranspirant aerosol and method for factory - Google Patents

Abstract

The present invention relates to a composition in aerosol antiperspirant, in suspension for topical application to human skin, comprising from 1 to 30% by weight of activated aluminum hydrochloride, solid, milled 1 to 30% by weight of an agent of liquid masking, from 30 to 90% of a propellant to expel the composition from a container and a carrier

Description

COMPOSITION OF ANTITRANSPIRANT AEROSOL AND METHOD TO MANUFACTURE DESCRIPTION OF THE INVENTION This invention relates to antiperspirant aerosol compositions suitable for topical application to human skin. Antiperspirant compositions suitable for topical application typically contain an antiperspirant material such as aluminum chlorohydrate, which acts to suppress the level of perspiration in the area of the body to which it is applied. The antiperspirant compositions are widely applied in the form of an aerosol spray driven by a pressurized propellant. Antiperspirant aerosol compositions typically have the antiperspirant material suspended in an anhydrous carrier, together with a propellant and a suspending agent. Other secondary ingredients may also be present and the composition is housed in a pressurized container. A major problem associated with all antiperspirants, including aerosolized antiperspirants, is that of depositing or whitening, where the active antiperspirant, which is usually in the powder form, is deposited on the wearer's or skin's clothes, so which causes visible bleaching / staining and occasionally damage to clothes. Several attempts have been made to reduce whitening or visible deposits. One widely used approach has been to incorporate masking oils, such as aliphatic hydrocarbons, esters and siloxane fluids in antiperspirant formulations. Generally, masking oils also have an emollient effect. The function of the masking oils by coating the surface of the active antiperspirant particles minimizes the dispersion of light, making the active ingredient less visible to the naked eye. It has been found that the method of masking to reduce whitening in products in bar and rotating ball. However, the reduction of bleaching in the aerosol compositions containing activated aluminum chlorhydrate (AACH) as the active ingredient has been less effective. It proved to be particularly difficult to couple the refractive index (Rl) of the masking oil with that of the AACH, since the commercially available AACH does not have a continuous Rl value in all the particles. More particularly, the AACH particles generally contain hollow cores, which have an Rl of 1.0, while the Rl of the outer particles is in the region of 1.5, which results in visible whitening. An object of the invention is to provide an antiperspirant aerosol composition, particularly improved one comprising a particulate antiperspirant active having reduced visible bleaching. Another object of the invention is to provide a method for producing an antiperspirant composition having reduced visible whitening. According to the invention, there is provided an antiperspirant aerosol composition, in suspension for topical application to human skin, comprising 1-30% by weight of solid or non-hollow activated aluminum hydrochloride, of 1-30% by weight. weight of a liquid masking agent, 30-90% of a propellant to expel the composition from a container and a carrier. Preferably, the activated aluminum hydrochloride comprises non-hollow particles. By "not hollow" in this context, particles are understood which do not contain nuclei or spaces which have a diameter greater than 40% of the diameter of the particle. Preferably, any of the cores or spaces are less than 30% of the diameter of the particle, more preferably less than 20% of the diameter of the particle, even more preferably less than 10% of the diameter of the particle, most preferably less than 5% of the diameter of the particle. Suitably, activated aluminum hydrochloride has a continuous refractive index. Preferably, the aluminum hydrochloride has a Refractive Index of 1.52 to 1.57 and the masking agent has a Refractive Index of 1.40 to 1.57. A preferred method for obtaining such AACH without or with very small cores or spaces is to obtain the AACH with very large particle sizes (e.g. 100 microns or more) and reduce these particles in size by grinding or grinding them. More preferably, the masking agent is selected from the group comprising esters benzoate, hydrogenated polybutene, butyl ether PPG-14, isopropyl palmitate, phenylsilicone and isopropyl myristate. In an alternative embodiment, the invention relates to the use of a solid activated aluminum hydrochloride (ie without gaps) in the preparation of an antiperspirant composition. The AACH antiperspirant active ingredients and methods for suitably producing them for use in the present invention are described in GB 1,568,831, GB 1,597,497, GB 1,597,498, EP 6,738, EP 6,739, EP 7,191, EP 191,628, EP 256,832 and EP 491,395, the contents of which are incorporated herein by reference. The particulate material is suspended in a liquid, emollient, hydrophobic masking agent. The masking agent improves the initial adhesion of the active antiperspirant to the skin, thereby aiding in the capture of the antiperspirant material through the skin as it is delivered in the form of a spray or aerosol. Also, the agent serves as a diluent, lubricant or a dispersing agent to facilitate the uniform distribution of the antiperspirant material in the skin. Suitable emollient liquid masking agents are described in U.S. Patent Nos. 4,822,596 and 4,904,463 the disclosures of which are specifically incorporated herein by reference. The amount of the emollient liquid masking agent in the composition, according to the invention preferably can vary from 1-30% by weight of the total composition. Preferred emollient masking agents are the Benzoate Finsolv Esters (Trade Mark) available from Finetex Inc. and Panalane, a hydrogenated polybutene available from Amoco, AP Fluid (Union Carbide), isopropyl palmitate, phenylsilicone and isopropyl myristate.

In an alternative embodiment of the invention, the emollient, liquid carrier element of the composition comprises a volatile silicone fluid. Preferred volatile fluids for use in the compositions according to the invention include dimethylcyclosiloxanes, such as the fluids DC244, DC245, DC344 and DC345 (Dow Corning). To prevent cake formation or settling of the antiperspirant salt in the emollient, hydrophobic liquid carrier, a bulking agent or suspension agent is preferably incorporated into the composition of the invention. The suspending agent is preferably a hydrophobically treated montmorillonite clay, such as bentonites and hectorites. One of such commercially available clay is Bentone-38, which is a hectorite clay available from NL Industries, Inc. The amount of clay in the composition of the invention, preferably may vary from 0.2-5.0% by weight of the total composition . The propellant gas according to the invention can be any liquefiable gas known in the art for use in propellant-driven aerosol containers. Examples of suitable propellants include trichlorofluoromethane, trichlorotrifluoromethane, difluoroethane, propane, butane or isobutane or combinations thereof. The amount of propellant in the composition of the invention conveniently is not more than 90% by weight. Other secondary ingredients which may be present in the compositions according to the invention include: cosmetically acceptable vehicles, such as straight and branched chain alcohols, for example ethanol, isobutanol or isopropanol; perfumes active deodorants and deodorant compounds, which can act as antimicrobial agents; hydrophobic oils, such as liquid paraffin oils; inorganic electrolytes, such as sodium chloride or sodium sulfate; other thickeners such as clays, silicas, for example, Aerosil 200 and hydroxypropyl celluloses such as Klucel; polar additives such as propylene carbonate or alcohol; skin-improving enhancers, such as talcum and finely divided polyethylene, such as Accu ist R38; humectants, such as polyols, for example glycerol; perfumes; preservatives and antioxidants; agents for the benefit of the skin such as allantoin; - colors; other cosmetic adjuvants conventionally employed in propellant-driven aerosol products. While not wishing to be bound by any theory, the Applicant believes that the poor masking associated with the antiperspirant aerosol compositions of the prior art is due to the morphology of the antiperspirant active ingredients used in the aerosol compositions. The active ingredients used in products in suspension, bar and rotating ball is AZAG. The AZAG particles are irregular in shape and have an average particle diameter of about 2 microns. The particles are solid in nature and are obtained by grinding larger particles. The "whitening" of the deposits in the skin using products in suspension in bar and revolving ball, is usually more intense than for the aerosol due to the use of smaller particle sizes, in such a way that the products that provoke more surfaces of Dissemination of light that will be exposed to light. Smaller particle sizes are used to prevent the settling of the active ingredient during placement of the antiperspirants in bar and rotating ball to facilitate resuspension. In contrast, the larger macrospheric active agents are used in aerosol formulations partly for safety reasons. The active ingredient for aerosol favored is the AACH, in the form of almost spherical particles of average diameter for example 20-30 microns, which can be produced by reducing the particle size of the particles which originally had a size in the region of 100 microns. The original particles have a hollow core, that is, they are in the form of a cover that encloses a core that contains air, hollow. The masking oils help to eliminate bleaching as previously described. However, it is believed that although the refractive index of the oil can be coupled with the particle cover to reduce visible masking, a decoupling in the refractive index between the shell and the hollow core remains. Hence, the processing to eliminate the hollow core and therefore the difference in the refractive indexes, is beneficial.

More particularly, the active antiperspirant has a Refractive Index (IR) of 1.52-1.57, that of the oils is 1.40-1.57 and the IR of the air is 1.0. It is believed that the core-shell interface acts as the main dispersion source in the presence of the oil, to cause the excessive visible bleaching experienced with the aerosol formulations.

Examples The invention will now be described by way of example only. The following compositions were prepared using standard techniques known in the art. 1_, Comparative A solid produced by the supplier (ie, without trapped air) of active Locron S (ex Hoechst) aluminum hydrochloride of particle size (e.g. about 100 microns) is milled at an average particle size of 30 microns. , which is comparable to that of the active AACH (ex Giuilini), and these are combined with four masking oils to determine the percentage reduction of whitening.

Whitening measurements are obtained by a sprayed (ie active) deposit weighing 0.2 g. The results are given in the following table. The results show that the level of bleaching (as measured using digital image analysis under controlled lighting conditions) for the two active ingredients (AACH and ground ACH) are very close in the absence of the masking oil. In the presence of the oils, the whitening level of the ACH is, in all cases, lower than that of the AACH. The percentage of reduction of bleaching is given in parentheses.

It should be noted that the refractive indices of the AACH and the ACH are 1.52 and 1.53 respectively. Therefore, the differences in masking can not be explained by a difference in the IR values of the active ingredients.

Accordingly, a ground AACH particle, which is solid, ie does not contain a hollow core or is not a hollow spheroid particle, would clearly result in reduced whitening. The active ingredient AACH can be prepared as described in the references mentioned hereinbefore incorporated herein. 2. Compositions An antiperspirant aerosol composition, driven by a packaged propellant, is prepared to have the following formulation: The masking oils were replaced in the formulation at a level of 10% by replacing 10% of the volatile silicone. 3_j. Whitening reduction The following example shows the results of the variation in an antiperspirant aerosol composition, standard the level of a masking agent fluid and an active antiperspirant, in particular with respect to the morphology of the antiperspirant active agent. The "base" composition for the aerosol contains the amounts of the masking agent and the antiperspirant active ingredient showed with 13% volatile silicone, 1% Bentone 38 and the remainder being the propellant bentone / propane / isobutane. In such spray aerosol composition, under consistent spray and observation conditions, a Quantitative Descriptor Analysis (QDA) classification is attributed to various aerosol formulations in which the level of masking fluid and nature of the antiperspirant salt is varied.

Results The results show that the addition of increasing the levels of the masking agent to normal AACH (which has a hollow core) has a relatively small effect on perceived whitening. However by grinding the AACH and thereby removing the hollow core from the AACH particles, a large reduction in perceived whitening is observed. The reduced bleaching of ACH compared to AACH further emphasizes the importance of the hollow core in the AACH particles in determining the perceived whitening. 4. Whitening reduction Again a standard antiperspirant aerosol composition containing varying amounts of the antiperspirant active agent and the masking fluid in the same aerosol base as described in Example 3. Bleaching is measured by image analysis techniques. The figures in parentheses indicate the change in bleaching compared to the standard of 10% of AACH hollow and without masking oil.

Therefore the figures indicated that with the ground AACH, a huge reduction in bleaching can be achieved by the use of relatively little masking oil, compared to similar formulations containing ACH and AACH without grinding.

Claims (7)

1. A suspension antiperspirant aerosol composition for topical application to human skin, characterized in that it comprises from 1-30% by weight of activated aluminum hydrochloride, solid, 1-30% by weight of a liquid masking agent, 30-90 % of a propellant to expel the composition from a container and a carrier.

2. The aerosol composition according to claim 1, characterized in that the activated aluminum hydrochloride does not comprise hollow particles.

3. The aerosol composition according to claim 2, characterized in that the activated aluminum hydrochloride has a continuous refractive index.

4. The aerosol composition according to claim 3, characterized in that the activated aluminum hydrochloride has a Refractive Index of 1.52 to 1.57.

5. The aerosol composition according to claim 4, characterized in that the masking agent has a Refractive Index of 1.40 to 1.57.

6. The aerosol composition according to claim 5, characterized in that the masking agent is selected from the group comprising esters benzoate, hydrogenated polybutene, PPG-14 butyl ether, isopropyl palmitate, phenylsilicone and isopropyl myristate.

7. The use of an activated, solid aluminum hydrochloride in the preparation of an antiperspirant composition.