Structural characterization and stability of dimethylaminoethanol and dimethylaminoethanol bitartrate for possible use in cosmetic firming.

2-Dimethylaminoethanol (DMAE) (also known as deanol) has been used as an ingredient in skin care, and in cognitive function- and mood-enhancing products. It is marketed as a free base or salt, and in theory, the two forms should be equally effective and able to substitute for each other in pharmaceutical formulations. Detecting possible alterations in the active principle is a basic part of preformulation studies. Accordingly, this study compared DMAE and DMAE bitartrate to identify potential alterations or differences between the free base and the salt that might compromise the long-term stability of cosmetic preparations at different temperatures, and also compared the behavior of the base substance and derivative alone and in solution. Samples were analyzed with different physicochemical methods such as differential scanning calorimetry, ultraviolet and infrared spectroscopy, and nuclear magnetic resonance spectroscopy.