Antiperspirant active compositions and manufacture thereof

A method of making an antiperspirant active composition comprising:

• I) heating an aqueous solution containing a first aluminum salt having an aluminum to chloride molar ratio of 0.3:1 to 3:1 and a buffer, wherein the buffer is an amino acid or betaine and a molar ratio of buffer to aluminum is at least 0.1:1, at a temperature of 50° C. to 100° C. for a period of time of 1 hour to 6 hours to obtain a first aluminum salt solution;
• II) adding to the first aluminum salt solution an aqueous solution of an inorganic base to obtain a second pH adjusted aluminum salt solution having an OH:Al molar ratio of at most 2.6:1 and a pH of 2 to 5;
• III) heating the second pH adjusted aluminum salt solution at a temperature of 50° C. to 100° C. for a period of time of at least 6 hours to obtain a third aluminum salt solution containing a third aluminum salt exhibiting an 27Al NMR spectrum with a species distribution including at least 95% Al30 polyhydroxyoxoaluminum cation as the predominant species detectable by 27Al NMR within the third aluminum salt;
• and
• IV) optionally adding an aqueous solution containing a zirconium compound to the second pH adjusted aluminum salt solution to thereby obtain a second pH adjusted aluminum-zirconium salt solution having a molar ratio of aluminum to zirconium of 5:1 to 10:1.