CA2586725A1 - Activated aluminum/depolymerized zirconium antiperspirant compositions - Google Patents

Abstract

An aluminum-zirconium antiperspirant composition comprising activated aluminum and depolymerized zirconium species is characterized by an Inductively Coupled Plasma (ICO)-Size Exclusion Chromatograpy (SEC)-HPLC method. A good correlation is obtained between the intensity of the zirconium peak at retention time of about 4.3 minutes to about 4.9 minutes by ICP-SEC-HPLC and the extent of the polymerization of the zirconium species, such that the higher the intensity of the zirconium species, the greater the polymerization of the zirconium species. The extent of the polymerization of zirconium species in the activated aluminum-zirconium salt is affected by the factors and reaction conditions such as the ratio of chloride to zirconium in a zirconium hydroxy chloride (ZHC) solution; the heat treatment of the ZHC
glycinate solution; and the concentration of activated basic aluminum chloride (BAC) solution. Controlling the reaction conditions yields a novel aluminum-zirconium antiperspirant salt of enhanced efficacy having activated aluminum and depolymerized zirconium species.

Description

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ACTIVATED ALUMINUM/DEPOLYMERIZED ZIRCONIUM ANTIPERSPIRANT
COMPOSITIONS

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This invention relates to aluminum-zirconium antiperspirant compositions of enhanced efficacy comprising activated aluminum and depolymerized zirconium species and the metliods of making said compositions.

BACKGROUND OF THE INVENTION

Antiperspirants of enhanced efficacy usually have high SEC-HPLC Band III, with Band III to Band II area ratio of at least 0.5. The activation of aluminum is achieved by the dilution and heat treatment of aluminum chlorohydrate (ACH) solution. Heating the inore diluted ACH solution for a longer period of time produces an activated aluininum antiperspirant with higher Band III/II ratio. The Band III aluminum species are generally very reactive and quickly revert back to Band II aluminum species. The activated aluminum solutions are dried to powders in order to preserve their eiihanced efficacy.
Prior art describing the preparation of such salts include the following:
U.S. Patent No. 4,359,456 which describes a process of heating 2.5% to 8.5% by weight ACH solution at 50 C to 140 C from 0.5 hour to 30 days that gives a composition having SEC-HPLC Band III of at least 20% aluminum.
GB2048229A describes an activated aluininum salt made by aging or heating from 5% to 40% by weight ACH from 50 C to 100 C. The patent does not disclose any preferred SEC-HPLC profile.
U.S. Patent No. 4,944,933 discloses a direct process of making activated basic aluminum chlorohydrate solution at 7.5% to 13% by weight having an aluminum to cliloride ratio of 1.7:1 to 2.2:1 and a Band III fraction of at least 20%.
U.S. Patent No. 5,356,609 describes a process of malcing basic aluminum chloride solution with high Band III of at least 25% by the direct reaction of A1C13 solution with Al powder at 50 C to 100 C and at a conceiltration of about 8% to about 25% by weight. The product has a large amount of Alb species.
U.S. Patent Publication No. 2004/0101500 Al provides a method of making an activated aluminum salt solution having a ratio of aluminum to chloride ranging from 1.5:1 to 2.0:1 and an aluminum concentration ranging from 0.5% to 3.8% by weight. Heat treatment of the solution is involved. The aluminum salt has a ratio of SEC-HPLC Band III to Band II
of greater than 3:1.
Activated aluminum-zirconium antiperspirant salts are produced by the addition of zirconium compounds to the activated aluminum solutions, which are dried to powders due to the fast change of Band III into Band II in solution fornis that result in the loss of efficacy of the corresponding salts. The introduction of zirconium species into these aluminum salt solutions fiu-ther depolymerize the aluminum species, which results in a change in the distribution of aluminum species and an increase in efficacy is observed. The zirconium species, on the other hand, become further polymerized during the process and the effect is more pronounced wlien activated aluminum solutions are involved. Patents describing the preparation of such activated aluminum-zirconium antiperspirant salts include:
U.S. Patent No. 4,775,528 which discloses an aluminum-zirconium solid composition of enhanced efficacy. The process of making includes firstly, heating a 2% to 18% by weiglit ACH solution at a teinperature of at least 50 C for a certain period of time, secondly mixing zirconium hydroxy chloride with the solution before, during or after the heat treatment of the diluted ACH solution and thirdly drying the solution to a powder. No differences in the final compositions were observed between addition of the zirconium species to the aluminum solution before, during or after the heat treatment. The sequence of the addition however, has a substantial effect on the degree of polymerization of the zirconium species.
The aluminum-zirconium salts prepared according to U.S. Patent No. 4,775,528 show a large SEC-HPLC
peak 1, which is an indication that the zirconium species are greatly polyinerized.
U.S. Patent No. 4,871,525 teaches a process of inaking an aluminum-zirconium lzydroxychloride glycinate complex having a pealc 4 to peak 3 pealc height ratio of 0.5 to 1.8 and peaks (1+2) contain less than 4% of the total distribution by weight. The process involves mixing an aqueous zirconyl hydroxychloride solution with an 8% to 35%
by weight basic aluminum chloride solution at a temperature of from 500C to 100 C for a period of time of less than 2 hours to form a coinbined solution. Zirconium species are furtlier polymerized during the heating process, which can not always be demonstrated by SEC-HPLC
profile depending on the types of size exclusion colunms involved and the experimental conditions employed.
U.S. Patent No. 4,900,534 discloses a direct process of making aluminuzn-zirconium salt by dissolving aluminum metal in an aqueous solution comprising zirconium oxychloride and aluminum chloride at about 50 C to 105 C. The solution of the final aluminum-zirconium chlorohydrate has a concentration of metal of 0.5 to 2.3 moles/Kg and a SEC-HPLC Band III of at least 20%. The high temperature treatment polymerizes the zirconium species substantially, which results in the loss of effectiveness of the antiperspirant.
EU0653203 Al teaches an improved process for inaking novel zirconium salts which involves mixing zirconium starting material and glycine at ambient temperature and combining said zirconium/glycine aqueous mixture witli an aluminum chlorohydrate starting material then rapidly drying the resultant aluminum chlorohydrate/glycine/zirconium mixture. There is no disclosure related to the effect of Cl/Zr ratios of the zirconium solutions and the concentrations of the aluminum chlorohydrate solutions on the polymerization of the zirconium species, which are generally accepted as crucial to the efficacy of aluminum-zirconium antiperspirant.

U.S. Patent No. 6,375,937 B1 describes aii aluminum-zirconium chlorohydrate composition witli low metals to chloride ratio of from 0.9 to 1.2 and a glycine to zirconium molar ratio greater than 1.3. The active salt can be prepared by three different methods; the mixing of zirconyl chloride with activated ACH salt is one of the disclosed methods. The ratio of glycine to zirconium of the said composition is greater than 1.30.
U.S. Patent No. 6,436,381 B1 discloses enhanced efficacy aluminum-zirconium antiperspirant compositions having SEC-HPLC pealc 5 of about 33% or more and an SEC-HPLC peak 4 to pealc 3 area ratio of at least 0.4. The salt compositioiis have a low metal to chloride ratio of about 0.9 to about 1.0, which when applied can give rise to skin irritation.
The enhanced efficacy of aluminum-zirconium antiperspirant salts is generally achieved through the activation of aluminum species and the extent of the activation is characterized by different methods sucli as SEC-HPLC, 27A1 NMR and Ferron analysis.
These metliods mostly characterize the aluminum species. There is very little information generally available about the nature and extent of polymerization of the zirconium species in antiperspirant salts. There are limited methods available for the characterization of zirconium species that restricts the understanding of the zirconium chemistry that contributes to the eiilianced efficacy of aluminum-zirconium antiperspirant salts.

It would be highly desirable to provide aluminum-zirconium antiperspirant salts having increased efficacy comprising both activated aluminum species and depolymerized zirconium coinplexes. Such aluminum-zirconium antiperspirant compositions will provide higher efficacy than the conventional prior art salts heretofore described under the same conditions, such as Al to Zr ratio and metal to chloride ratio content.

SUMMARY OF THE INVENTION

According to the present invention an Inductively Coupled Plasma (ICP) instrument is applied to characterize the extent of the polymerization of zirconium species of activated aluminum-zirconium antiperspirant salts. The zirconium species are first separated by Size Exclusion Chromatography (SEC) operated via a High Performance Liquid Chromatograh (HPLC). It was discovered that after SEC-HPLC separation, analysis by ICP
revealed a good correlation between the intensity of the zirconium pealc at retention time of about 4.3 minutes to 4.9 minutes and the extent of the polymerization of the zirconium species, i.e., the higher the intensity of the zirconium species, the greater their degree of polymerization.
The extent of polymerization of the zirconium species in an activated aluminum-zirconium salt is affected by several factors such as (a) the ratio of cliloride to zirconium in a zirconium hydroxy chloride (ZHC) solution; (b) the heat treatment of ZHC
glycinate solution; and (c) the concentration of the activated basic aluminum chloride (BAC) solution.
By carefully controlling the reaction conditions, a novel aluminum-zirconium antiperspirant salt of enhanced efficacy is obtained, comprising activated aluminum and depolymerized zirconium species. Specifically, the activated aluminum-zirconium salt of this invention is prepared by (1) heating a solution of about 15% to 25%, preferably 18% to 22%, by weight, BAC solution having an aluminum to chloride ratio of about 1.5 to about 2.1, preferably fiom about 1.8 to about 2.0, at a temperature of at least 50 C, preferably higher, for a period of time sufficient to yield the desired activation; (2) blending a concentrated ZHC glycinate solution that has been heated at a temperature of greater than 50 C with the heated BAC
solution at RT, and (3) drying the blended final solution to a powder.

BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is the SEC-HPLC of ZHC solution with Cl/Zr ratio of 1.05.
Fig. 2 is the SEC-HPLC of ZHC solution with Cl/Zr ratio of 1.27.
Fig. 3 is the SEC-HPLC of ZHC solution with Cl/Zr ratio of 1.53.
Fig. 4 is the ICP-SEC-HPLC of ZHC solution with Cl/Zr ratio of 1.05.
Fig. 5 is the ICP-SEC-HPLC of ZHC solution with Cl/Zr ratio of 1.27.
Fig. 6 is the ICP-SEC-HPLC of ZHC solution with Cl/Zr ratio of 1.53.
Fig. 7 is the SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.05 at RT.
Fig. 8 is the SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.05 at 80 C.
Fig. 9 is the SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.05 at reflux.
Fig. 10 is the SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.53 at RT.
Fig. 11 is the SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.53 at 80 C.
Fig. 12 is the SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.53 at reflux.
Fig. 13 is the ICP-SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.05 at RT.

Fig. 14 is the ICP-SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.05 at 80 C.
Fig. 15 is the ICP-SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.05 at reflux.
Fig. 16 is the ICP-SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.53 at RT.
Fig. 17 is the ICP-SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.53 at 80 C.
Fig. 18 is the ICP-SEC-HPLC of ZHC glycinate solution with Cl/Zr ratio of 1.53 at reflux.
Fig. 19 is the ICP-SEC-HPLC of activated Al-Zr powder with M/Cl ratio of 1.13 and with ZHC glycinate solution made at RT .
Fig. 20 is the ICP-SEC-HPLC of activated Al-Zr powder with M/Cl ratio of 1.25 where ZHC glycinate solution was forined at RT.
Fig. 21 is the ICP-SEC-HPLC of activated Al-Zr powder with M/Cl ratio of 1.25 where ZHC glycinate solution was formed at 80 C.
Fig. 22 is the SEC-HPLC of activated Al-Zr powder with M/Cl ratio of 1.25 where ZHC glycinate solution was formed at RT.
Fig. 23 is the SEC-HPLC of activated Al-Zr powder with M/Cl ratio of 1.25 where ZHC glycinate solution was formed at 80 C.
Fig. 24 is the 27A1 NMR of activated AI-Zr powder according to Experiment 8 in Exainple 2 (Table II).

DETAILED DESCRIPTION OF THE INVENTION

The present invention describes enhanced efficacy aluminum-zirconium antiperspirant salt compositions comprising activated aluminum and depolymerized zirconium species. The compositions have a SEC-HPLC Band III to II area ratio of at least 0.5, preferably at least 0.7 and nlost preferably at least 0.9, which are achieved by the heating of 15% to 25% by weight basic aluminum salts having the formula Al2(OH)6_aXa wherein X is Cl, Br, I or NO3, a is from about 1 to about 1.4, with basic aluminum chloride solution the most preferred. It is preferable to have a BAC solution with aluminum to chloride ratio of about 1.3 to about 2.1 and most preferably froin about 1.6 to about 2Ø The time of the heating depends on the teinperatures, as longer times are usually required at lower temperatures and shorter times at higher temperatures. It is preferred to heat the diluted BAC
solutions at 50 C, preferably at 80 C and most preferably at reflux for at least 2 hours. The concentration of the BAC solutions has a large effect on the extent of the polymerization of the zirconium species in the activated aluminum-zirconium antiperspirant salt.
It was observed that zirconium species polymerized furtlier at lower BAC
concentrations. In order to achieve the increased efficacy of the combined salt, it is preferable to have about 15% to about 25% by weight BAC solutions and most preferably about 18% to about 22%
by weight of BAC solutions.
Zirconium compounds useful in the present invention have the formula ZrO(OH)bX2-b wlierein b is a numerical number from 0 to 1.2, X is Cl, Br, I or NO3, with chloride being the most preferred. The zirconiuin hydroxychloride solution can be prepared by the reaction of basic zirconium carbonate with hydrochloric acid or zirconyl chloride at elevated temperature for a certain period of time. It has been found that there is not a substantial difference in the polymerization of the zirconium species in ZHC solution prepared by the above two different methods, especially at higher chloride to zirconium ratio. The conditions of the preparation such as the preparation temperature, heating time and the concentration of the ZHC solutions have greater effects on the polymerization of zirconium species. The polymerization of the zirconium species is largely controlled by the chloride to zirconium (Cl/Zr) ratio of the ZHC
solutions, i.e., the higher the Cl/Zr ratio the more the depolymerized the zirconium species. It is desirable to have ZHC solutions with Cl/Zr ratio of at least 1, preferably of at least 1.4, and more preferably of at least 1.6. The ZHC solutions are further mixed with an amino acid, preferably glycine, at a temperature of about 50 C, preferably at about 80 C
to reflux, for a period of about 1 liour to about 4 hours. It has been observed that the heating of the ZHC
glycinate solutions has a very substantial effect on the degree of polymerization of the zirconium species in the final aluminum-zirconium antiperspirant salt, especially at higher Cl/Zr ratio. Heating the ZHC glycinate solution at 80 C for 1 hour for example, greatly depolymerized the zirconium species, sometimes to a greater extent, even at lower Cl/Zr ratios, than mixing the higher Cl/Zr ratio ZHC glycinate solution at RT.
The amino acids that may be used include glycine, alanine, lysine, ornithine, citrulline, hydroxyproline, cysteine, threonine, valine, serine, methionine, glutamic acid and the mixtures thereof. Glycine is the most preferred amino acid. The quantity of glycine is controlled such that the glycine to zirconium molar ratio is of about 1.

The aluminum-zirconium solution is prepared by mixing the activated BAC
solution with heat treated ZHC glycinate solution at RT for a certain period of time generally no more than 1 hour and the final solution is dried to a powder by any appropriate means, including freeze-drying and vacuum drying. Spray drying is the most preferred method.
The aluminum-zirconium salts thus prepared have a M/Cl ratio of more than 1, and most preferably at least 1.2. Aluminum-zirconium antiperspirant salts with veiy low M/Cl ratios of 1 or less generally have iuicreased efficacy. However, these salts are very difficult to forinulate. The difficulties include fragrance stability, yellow color and softness of the sticlc when these salts are used. They can also be irritating to skin. The aluminum-zirconium salts according to the present patent having a M/Cl ratio of 1.2 or above demonstrate increased efficacy from both activated aluminum and depolymerized zirconiuin species, are easy to formulate and generally more mild to the skin.
The characterization of aluminuin and zirconium species in aluminum-zirconium antiperspirant salts are determined by the following methods:
SEC-HPLC
The degree of the polymerization of aluminum complexes is determined by Size Exclusion Chromatography (SEC) operated via a High Performance Liquid Chromatograph (HPLC) instrument. In this technique, the highest molecular weight Al species are eluted first and are designated as Band I or otherwise called pealcs 1 and 2. Band II (or peak 3) and Band III (or pealc 4) are due to intermediate molecular weight Al complexes. Band IV or peak 5 is due to the lowest molecular weight Al complexes, including monomers and diinmers. The relative area of one or more peaks is determined in order to characterize the distribution of polymeric species in aluminum complexes formed. The aluminum-zirconium antiperspirant salts of the present invention have SEC-HPLC Band III to Band II area ratio of at least 0.5, preferably at least 0.7, and most preferably at least 0.9.
A Phenominex column and a Waters column connected in series (dual coluinn) are used to obtain a SEC-HPLC Cliromatogram. Each sample is dissolved in deionized water to form a 2% by weight Al solution. Each sample is filtered through a 0.45 filter and chromatographed within 15 minutes using a 0.01N nitric acid solution as the mobile phase.
Nuclear Magnetic Resonance Spectroscopy 27A1 Nuclear Magnetic Resonance (NMR) is utilized to identify the structures of different aluminum species in the activated aluminum-zirconium antiperspirant salts of enhanced efficacy. The antiperspirant salt in solution form is measured as is and the powder is dissolved in deuteriated water to form a 10% by weight solution just before the measurement. Data were collected using a Varian Inova 400 instrument at 104.2 MHz.
Generally a sharp peak at chemical shift of about 0 ppm by 27A1 NMR indicates the presence of monomeric octahedral Al species. A sharp peak at about 63 ppm fiom a tetrahedral aluminum species, indicates the presence A113 species which contains one tetrahedral Al center. The other 12 octahedral Al centers in this coinpound have pealcs that are too broad to be detected. A broad chemical shift at about 72 ppm is also from tetrahedral aluminum species and indicates the presence of A141 species. Larger aluminum species usually show chemical shifts that are too broad to be detected. The aluminum-zirconium antiperspirant salts of enhanced efficacy comprising activated aluminuzn and depolymerized zirconium species according to the present invention do not show sharp peaks at about 63 ppm.
Inductively Coupled Plasma Spectroscopy (ICP) SEC-HPLC
The present invention employs ICP-SEC-HPLC aiialysis to study the polymerization of zirconium species and the distribution of the aluminum polymers. The size exclusion column operated by HPLC has been used to separate the aluminum and zirconium polyiners by size. The separated species are sent to the ICP instead of a refractive index (RI) detector as in regular HPLC. Prior to the analysis, the colum.n was conditioned by repeated injections of a 10% aluminum-zirconium tetrachlorohydrex glycine solution until the area of Band I is constant. The SEC-HPLC data for aluminum-zirconium salt obtained by using RI
detector are sometimes found to be misleading with respect to the distribution of zirconiuin species as can be seen from Figs. 20 to 23. This is because firstly the RI detector is not very sensitive to the zirconium species of aluminum-zirconium antiperspirant salts and secondly the zirconium pealc(s) at retention times between 4.3 minutes to 4.9 minutes overlap witll the aluminuin pealcs Band I and Band II, especially when activated aluminum-zirconium salts are involved.
When the separated species from the SEC column are detected by ICP, discrete zirconium and aluminum peaks are observed. Furthermore, the intensity of the zirconium peak(s) at retention times of 4.3 to 4.9 minutes changes with the apparent extent of polyinerization of the zirconium species.
The invention will be further illustrated by the following Examples. In the Examples, parts are by weight unless otherwise specified.

Example 1: Comparison of Basic Aluininum Cliloride Solutions Prepared by both Direct and Indirect Methods There are two methods for the preparation of the activated basic aluminum chloride solution. The first is a direct process, which includes the direct reaction of aluminum powder with aluminutn chloride solution at elevated temperature. The second is an indirect process, which involves heating a diluted BAC solution at above 50 C for a certain period of time, preferably at reflux for about 4 hours. The following solutions are made by both the direct and indirect processes and their properties are listed in Table I.
Table I

Experiment Process Al/Cl Ratio Concentration Ferron analysis Number %w/w %Alb 1 direct 1.88 25% 41.0 2 direct 1.78 25% 29.6 3 indirect 1.75 25% 3.8 4 Indirect 1.90 25% 6.8 The data indicate that there is a different distribution of aluminum species in the diluted BAC solutions when made by either the direct and indirect process. The activated BAC solution made from the direct process contains more Alb species that is not considered to be efficacious as an antiperspirant. It is preferable to make a solution having a concentration of about 15% to 25% by weight solution of activated BAC through the indirect process.

Example 2: Zirconium Hydroxy Chloride Solutions with Different Chloride to Zirconium Ratios Three ZHC solutions were made by dissolving basic zirconium carbonate paste in aqueous zirconyl chloride solutions at about 60 C until clear. The ZHC
solutions have zirconium contents of about 20% with Cl/Zr ratio of 1.53, 1.27 and 1.05, respectively. The SEC-HPLC profiles of the three ZHC solutions are illustrated in Figs.1, 2 and 3 with zirconium species eluted at retention time(s) of about 4.5-4.9 minutes and chloride at about 7.5 minutes. The solutions were also analyzed by ICP-SEC-HPLC and the chromatograms are shown in Figs. 4, 5 and 6. Both SEC-HPLC and ICP-SEC-HPC indicate that the degree of polymerization of zirconium species increases with the basicity of ZHC
solutions as measured by the refractive index of SEC-HPLC and the intensity of the concentration of zirconium species of ICP-SEC-HPLC.

Example 3: Comparison of Zirconium Hydroxy Chloride Glycinate Solutions Heated Versus Unheated The ZHC solutions with Cl/Zr ratios of 1.53, 1.27 and 1.05 prepared above were mixed with glycine at glycine to zirconium molar ratio of about l. The ZHC
glycinate solutions were then mixed at RT for 2 hours, 80 C for an hour and refluxed for 2 hours, respectively. The solutions were subjected to both SEC-HPLC and ICP-SEC-HPLC.
Some of the chromatographs are illustrated in Figs. 7 through 18. The data indicate that zirconium species become depolymerized upon addition of glycine and the depolymerization of the.
zirconium species is more effective at higher temperature such as at 80 C and reflux as suggested by ICP-SEC-HPLC, which is not observed by SEC-HPLC especially at higher Cl/Zr ratio. At lower Cl/Zr ratio such as about 1, the addition of glycine does not depolymerize the zirconium species substantially, both at RT and higher temperatures.
Example 4: Effect of the Concentration of BAC Solutions on the Polymerization of Zirconium Species in the Activated Al-Zr Salts Six activated aluminum-zirconium antiperspirant powders were made by mixing ZHC
(Cl/Zr, 1.37) glycinate solutions with six activated BAC solutions (Al/Cl, 1.8) at different concentrations of 10%, 15%, 18%, 20%, 22% and 25% by weight, respectively. All six solutions were treated with the same small quantity of hydrochloric acid, then spray dried to give six corresponding powders. SEC-HPLC, 27Al NMR and ICP-SEC-HPLC were performed on the powders and the results are as follows:
Table II

Experiment %BAC by SEC-HPLC Al NMR Intensity of Number weight %@Oppm Zr(RT-4.5 min.) by %I III/II IPC-SEC-HPLC

10 1.9 3.9 11.0 -1070 6 15 1.6 2.2 14.3 -960 7 18 2.4 1.6 14.6 -950 8 20 2.2 1.3 17.3 -870 9 22 0 1.0 12.4 -600 25 1.9 0.8 14.8 -1110 Example 5: Effects of M/Cl Ratio and Heat Treatnient of ZHC Glycinate Solutions on the Polymerization of Zirconium Species of the Activated Al-Zr Antiperspirant Salts Four activated Al-Zr antiperspirant powders were prepared with M/Cl ratios of 1.13, 1.25, 1.35 and 1.44 and Al/Zr ratio of about 3.3. These were made by treating about 25% by weiglit activated BAC solutions with zirconyl chloride glycinate solution and ZHC glycinate solutions at Cl/Zr ratios of 1.61, 1.27 and 1.05, respectively, followed by spray drying.
A-iiother sample was also made similar to the powder with M/Cl ratio of 1.25 except that the ZHC glycinate solution was heated at 80 C for 1 hour. The SEC-HPLC and ICP-SEC-HPLC
data are summarized in Table III.
Table III

Experiment M/Cl Ratio ZHC-glycinate SEC-HPLC Intensity of Zr Number solution (RT-4.5 min.) by %I III/II IPC-SEC-HPLC
11 1.13 RT 0 0.9 -115 12 1.25 RT 0 0.7 -430 13 1.36 RT 0 0.5 -920 14 1.44 RT 3.9 0.4 -1830 15 1.25 80 C/lhour 0 0.7 -165 ICP-SEC-HPLC and SEC-HPLC profiles of the activated Al-Zr AP powders at M/Cl ratios of 1.13 and 1.25 from ZHC glycinate solutions formed at botlz RT and 80 C are illustrated in Figs. 19 through 23. The data further support that zirconium species depolymerize at lower M/Cl ratios such as 1.13 and that a similar extent of depolymerization of the zirconium species can be achieved at higher M/Cl ratios such as 1.25 by the heat treatment of ZHC glycinate solutions. The ICP-SEC-HPLC data also indicate that the SEC-HPLC Bands I, II and III can be misleading with respect to the concentration of aluminuin species.
The present invention may be embodied in other specific forms without departing from the spirit of essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specifications as indicating the scope of the invention.

Claims (25)

1. A method of making solid aluminum-zirconium compositions of increased efficacy consisting of activated aluminium and depolymerized zirconium species having an SEC-HPLC Band III to Band II area ratio of at least 0.5 comprising:
(i) heating a solution from about 15% to about 25% by weight of a basic aluminum salt of the formula Al2(OH)6-a X a wherein X is Cl, Br or NO3, wherein a is from about 1 to 1.4 from 50°C
to about reflux for a period of time from about 2 hours to about 20 hours and cooling to RT;
(ii) heating a solution of a zirconium compound of the formula ZrO(OH)b X2-b with an amino acid wherein b is a numerical number from 0 to 1, X is Cl, Br or NO3 to at least 50°C;
(iii) blending said basic aluminum salt solution of (i) and said zirconium amino acid solution of (ii) at RT; and (iv) drying the blended solution of (iii) to a powder solid.

2. The method according to claim 1 wherein the amino acid is glycine.

3. The method of claim 1 wherein the SEC-HPLC Band III to II area ratio is at least 0.7.

4. The method according to claim 1 wherein the aluminum salt is a basic aluminum chloride (BAC) with an aluminum to chloride ratio of the BAC is from about 1.4 to about 2.1.

5. The method according to claim 4 wherein the aluminum to chloride ratio of the BAC is from about 1.5 to about 1.9.

6. The method of claim 1 wherein the heating, step (i) heated at reflux for at least 2 hours.

7. The method of claim 1 wherein the heating, step (i) heated at reflux for at least 4 hours.

8. The method according to claim 4 wherein the BAC solution comprises about 15% to about 25% by weight.

9. The method according to claim 8 wherein the BAC solution comprises about 18% to about 22% by weight.

10. The method according to claim 8 wherein the ratio of aluminum to chloride is from about 1.6 to about 2Ø

11. The method of claim 1 wherein the zirconium compound is a zirconium hydroxychloride (ZHC) solution with a chloride to zirconium ratio of at least 1.

12. The method of claim 11 wherein the chloride to zirconium ratio of the ZHC
solution is at least 1.4.

13. The method of claim 12 wherein the step (ii) the heating of ZHC glycinate solution is at 80°C for 1 hour.

14. The method of claim 12 wherein the step (ii) the heating of ZHC glycinate solution is at reflux for 2 hours.

15. The method of claim 1 wherein the amino acid to zirconium molar ratio is between about 0.5 and 1.5.

16. The method of claim 15 wherein the amino acid is glycine.

17. An activated Al-Zr antiperspirant composition prepared according to the method of claim 1 and having an SEC-HPLC Band III to Band II area ratio of at least 0.5.

18. An activated Al-Zr antiperspirant composition prepared according to the method of claim 1 and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.

19. An activated Al-Zr antiperspirant composition prepared according to the method of claim 2 and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.

20. An activated Al-Zr antiperspirant composition prepared according to the method of claim 8 and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.

21. An activated Al-Zr antiperspirant composition prepared according to the method of claim and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.

22. An activated Al-Zr antiperspirant composition prepared according to the method of claim 13 and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.

23. An activated Al-Zr antiperspirant composition prepared according to the method of claim 14 and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.

24. An activated Al-Zr antiperspirant composition prepared according to the method of claim and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.

25. An activated Al-Zr antiperspirant composition prepared according to the method of claim 16 and having an SEC-HPLC Band III to Band II area ratio of at least 0.7.