[narna84]

hi,

I am not a chemist, my degree in in molecular biology but I had a query regarding mandelic acid and was wondering if an organic chemist could clear it up for me - sources on the internet have varied and reading chem journals started to hurt my brain.

It is concerning mandelic acid - is it lipid soluble?  ive read in places that it has 'lipid soluble properties' - which sounds like annoying double speak by cosmetic manufacturers (it is commonly used in cosmetics) trying to misrepresent their product.  Other sources say that it is only water soluble.  Most of these sources have affiliations hence my skepticism

here is a link to the structure

http://chemicalland21.com/industrialchem/organic/MANDELIC%20ACID.htm

thank you to anyone who can clear this up for me.

[azmanam]

Small molecular weight with a not-too-long 'greasy' hydrocarbon tail (the phenyl ring).  Free alcohol.  Carboxylic acid group (probably deprotonoated at physiological pH).  I say not very lipid soluble (disclaimer: I am not a biological chemist).

At physiological pH (~7.3) the carboxylic acid will be deprotonated (charged) and the hydroxyl group (alcohol) will be protonated.  That deprotonation will drive the deprotonated acid into water.  If it is in the protonated acid form, however, it might slip in to a nonpolar lipid phase, but the polar hydroxyl group and the polar carboxylic acid group and low molecular weight are fairly significant strikes against it going into a lipid phase.