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By: Steve Herman
Posted: July 13, 2011, from the July 2011 issue of GCI Magazine.
page 3 of 5
What did borax contribute to the cold cream formulation? It neutralized the cerotic acid in the beeswax (approximately 13% of beeswax by weight is cerotic acid), creating a conventional anionic emulsifier. When borax dissolves in water, it produces boric acid plus sodium hydroxide. The reaction of sodium hydroxide and cerotic acid produces sodium ceroate:
C25H51COOH + NaOH → C25H51COO-Na+
Sodium hydroxide alone produces the anionic emulsifier, but the boric acid buffers the system. For the chemistry geeks, the composition of beeswax2 and the stoichiometry of the neutralization reaction are in Composition of Beeswax.
One formulation note concerns the solubility of borax, which is 201 grams per 100 mL at 100°C but drops precipitously to 1.3 grams at 0°C. Consequently, excess borax in the cream can crystallize out, and also increase the pH of the system, which is already high. Phase volume is also critical for determining the type of emulsion produced: Less than 45% water creates a water/oil emulsion, greater than 45% an oil/water emulsion.
Today’s Cold Cream
The closest modern descendent of Galen’s invention is Pond’s Cold Cream. Unilever officially traces it to 1846. Theron T. Pond, a pharmacist from Utica, New York, introduced Pond’s Golden Treasure, based on witch hazel, but Pond’s didn’t actually market a cleansing cream until 1920. The ingredients of the classic Pond’s shows its close affinity for Galen: mineral oil, water, beeswax, ceresin, sodium borate, fragrance and carbomer.