otherwise rise to unsafe levels in hot environments or as a result of physical exertion. The apocrine glands are located mainly in the underarm and genital-anal areas, generally beside hair follicles. They produce a 60mL-per-day secretion of almost colorless to slightly grayish-yellow viscous liquid, typically containing about 98.5% water; 1.1% NaCl and other inorganic salts; and 0.4% lactic acid, ammonia and proteinaceous ingredients. The initial Sandalwood odor of the sweat vanishes as skin-resident bacteria quickly attack the organic items, degrading them to butyric and iso-valeric acids, mercaptans, indoles, amines and hydrogen sulfide. The eccrine sweat glands do not act in this fashion, but participate by keeping the areas moist. There is evidence that underarm malodors aggravate males and may attract females if not too intense. Aluminum Chlorohydrate (ACH) The earliest “dry powder” aerosol antiperspirants used “regular” ACH powder when they were first introduced about 1958. The formula was Al2(OH)5n•nCl, where the Al/Cl ratio was from 2.10/1 to 1.91/1. Some marketers boldly added small amounts of aluminum chloride to improve drying efficiency, but this caused cases of skin irritation for some sensitive people. About 1960, a supplier introduced a bimetallic powder, where some zirconium chlorohydrate Zr(OH)3n•xCl was blended with the ACH. It was decidedly more effective in keeping the underarm area dry—a problem with the aerosol, when compared to sticks and roll-ons. A few years later, a major marketer employed a toxicologist who questioned the possible long-term effects of inhaling the Al/Zr powder on the lungs. He pointed out that over-spray inhalation was a potential problem since the nose and mouth of users were, moreor less, in line with the direction of the spray when targeting the underarms. He conducted experiments with Rhesus monkeys (who were very costly and ill-tempered) since they have lung characteristics very similar to human lungs. He found some tissue reddening and duly reported this to the U.S. Food & Drug Administration (FDA). The FDA Over-the-Counter Antiperspirant (OTC AP) Review Panel rather quickly approved rule-making that banned zirconium compounds from further use in any aerosol products. Other marketers objected, stating that the powder particles could be manufactured with diameters in the range of >90%—well over 10 microns and virtually none over 45 microns, thus the alveolar sacs would not be impacted. The agency re At about this time (AUG-1982), the FDA developed its “Guide for Effectiveness Testing of OTC Drug Products.” Basically, it involved the testing of a statistically significant number of people—unofficially 13 or more. They were sprayed on one underarm with the product and on the opposite underarm with a placebo. The time was not indicated, but is thought to be about two seconds each. A weighed absorbent pad was placed on each underarm and they were then seated in a chamber warmed to 100°F and having a relative humidity of 30 to 40%. After about 30 minutes the pads were re-weighed. To pass the test, the product pad had to weigh 20% less than the placebo pad. Using this test, the original CFC products, averaging about 3.5% ACH, showed sweat reductions of about 25%. While they passed and could be legally labeled as “OTC” drugs, the results were considered marginally low. They were decidedly inferior to the 40% to 50% reductions of the early roll-on and stick alternatives. In 1985, the Reheis Chemical Co., a producer of ACH for antiperspirants, resolved the problem by introducing its new line of REACH 101, REACH 201 and REACH 501 activated ACH powders. The products were still pure ACH, but where the regular ACH product was an oligopolymer, with “n” (the unknown number) averaging about 11, the new REACH versions had lower “n” values. The company used a sophisticated chromatographic process to separate the three molecular species. Particle size distributions were established by mechanically shaking the raw powder through special silk bags. The aerosol industry was pleased to learn that the REACH compounds provided sweat reductions in the 40% to 50% range—essentially twice that found with regular ACH. By 1987, most aerosol marketers had converted to one of the REACH products. Table 1 illustrates how the aerosols compared to roll-ons and sticks with respect to sweat reduction: Table 1: UNDERARM SWEAT REDUCTION* Active Ingredient Percentage Type Product Propellant Efficacy (% Sweat Reduction) ACH 3.5 Aerosol CFCs 25 ACH 10.0 Aerosol Hydrocarbons 25 REACH 501 10.0 Aerosol Hydrocarbons 45 ACH 20.0 Stick — 40 ACH + ZCH** 20.0 Stick — 60 ACH 25.0 Roll-On — 40 REACH + ZCH** 25.0 Roll-On — 60 *The efficacy figures are approximate, due to many variables, such as delivery rate for aerosols, pay-out for sticks and human differentials. At an efficacy of about 65% to 75%, most subjects develop Miliaria—an inflammation of the sweat glands with eruptions of the small papules and vesicles, producing redness and itching, e.g. prickly heat. ** “Z” stands for zirconium. August 2016 Spray 15
Spray August 2016
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