[Determination of piritramid in plasma using high pressure liquid chromatography methods]

After alkalization piritramid and codeine (internal standard) were extracted from plasma thrice with ether, solvent was removed, the residue dissolved in a mobile phase (methanol-phosphate buffer pH 4.5. 7:3) and injected on the column (packing Lichrosorb RP-18). The amount (0.5-2.5 micrograms) of piritramid was determined, average recovery was 88%.