the separation and simultaneous determination , by high-performance liquid chromatography , of acetaminophen ( i ) , guaifenesin ( ii ) , pseudoephedrine hydrochloride ( iii ) , and pholcodine ( iv ) , together with a series of parabens ( methyl to butyl , v-viii ) in a cough mixture , has been demonstrated using a chemically bonded octadecylsilane stationary phase with a mobile phase of methanol-water-acetic acid ( 45:55:2 ) containing the ion-pairing agent octanesulfonic acid .
C0018305
guaifenesin
C0010200
cough