Modifier and additive effects in the supercritical fluid extraction of pseudoephedrine hydrochloride from spiked-sand and suphedrine tablets

The effect of modifier and additive composition upon pseudoephedrine recove ry from spiked-sand and Suphedrine tablets was examined, Recovery was shown to be dependent on CO2 density as well as on the addition of an ion pairin g agent to the matrix, The presence of methanol in the extraction vessel pr ior to SFE was shown to play a significant role in the ion-pair extraction process, Recovery was also shown to be a function of ion-pairing reagent co mposition and concentration. The most successful recovery was obtained in t he presence of 1-heptanesulfonic acid (HSA), sodium salt in methanol at a 5 :1 molar ratio (reagent to drug). The increased extractability in the prese nce of ion-pairing reagent was attributed to reduced analyte polarity and a nalyte-matrix displacement. Alternatively, a matrix-spiked mixture of metha nol and 1% water by itself was just as effective as a matrix-spiked mixture of methanol and HSA for attaining efficient extraction. Several in-cell (e .g. to the matrix) and in-line (e.g. to the fluid) modifiers were examined for the extraction of pseudoephedrine from Suphedrine tablets, The greatest pseudoephedrine recovery from Suphedrine tablets of 82% (7.0%) was achieve d with 10% (1% H2O) methanol-modified CO2 in the presence of 400 mu L of me thanol (1% H2O), Finally AgCl tests and infrared analyses were performed on two tablet extracts. It was confirmed that even in the absence of any in-c ell modifier, a small fraction of pseudoephedrine hydrochloride could be ex tracted.