Antiperspirant

A significant disadvantage consumers associate with many solid-form antiperspirants is that they often leave a noticeable white residue on skin and clothing after application. An optimal approach to formulating antiperspirant sticks with less visible product residue is to partially substitute non-volatile silicone and, more importantly, incorporate antiperspirant actives with unique physical properties.

The demand for optically clear products continues to grow in the world cosmetics market. The polyol content helps lower the active's refractive index and bring it closer to the base vehicle. These actives offer greater efficacy than conventional aluminum-zirconium and aluminum chlorohydrate complexes and provide low whitening characteristics to most formulas. Despite the undisputed efficacy of today's deodorant and antiperspirant actives, marketing departments and product formulators are still searching for alternative methods and materials to reduce body odor and perspiration.

The resident microflora of the skin suggests that they usually exist in acceptable numbers in a healthy equilibrium. This balance is partly due to the free fatty acids released by the bacterial breakdown of triglycerides having a limiting action on numbers but, more importantly, to the free sphingoid bases, which show growth inhibitory activity against Gram-positive bacteria, yeast, and molds. It is suggested that by topical application of phytosphingosine, the growth of undesirable micro-organisms will be inhibited, which may reduce body odor.

Modified corn starch and acrylate cross-polymers are two gripping physical means of reducing body odor. The modified corn starch is said to be particularly suitable for use in powder products, deodorants, and antiperspirants. It absorbs body moisture and imparts the skin a dry, lubricious feel. The mechanism may be contrasted with a macroporous cross-linked acrylate copolymer applied to the skin, which adsorbs the fatty acid components of human perspiration. The macroporous copolymer possesses a pore diameter too small to allow penetration by skin-resident bacteria, thereby retarding the decomposition of the fatty acids.