A cinchonidine salt, an (R)-(+)-1-(1-naphthyl)ethylamine salt and a (S)-(-)-1-(2-naphthyl)ethylamine salt of (-)-2-{[2-(4-hydroxyphenyl)ethyl]thio}-3-[4-(2-{4-[(methylsulfonyl)oxy]ph- enoxy}ethyl)phenyl]propanoic acid, processes for their preparation, their use in treating clinical conditions including lipid disorders (dyslipidemias) whether or not associated with insulin resistance and other manifestations of the metabolic syndrome, and pharmaceutical compositions containing them.