The observed precipitation in a lotion containing 4% hydroquinone and 0.03% tretinoin is evaluated. To bring both assets into solution, the alcohol concentration is systematically changed in addition to 10% propylene glycol. The results show that a minimum of 54 ml of 96 ° ethanol is required to resolve both assets. It is also shown that the addition of 0.2% vitamin C, as an antioxidant, is necessary to avoid discoloration of the lotion due to the presence of hydroquinone, depending on the storage time.
AUTHOR:
Apr. Valérie Schaus
Center for Pharmaceutical
Information, CWOA - APB.
Valerie.schaus@apb.be
Reproduced with approval from Pharmaceutical magazine for Belgium, September 2014.
The full article can be found in the attachment .