Enantiomeric separation of salbutamol from spiked urine extracted with solid stationary phase

Enantiomeric separation of salbutamol from spiked urine extracted with solid stationary phase

Teerapol Srichana, D. of Pharmaceutical Tech., F. of Pharmaceutical Sci., PSU.
Roongnapa Suedee, Asst. Prof., D. of Pharmaceutical Chemistry, F. of Pharmaceutical Sci., PSU.
Corresponding e-mail : srteerap@ratree.psu.ac.th

Published : Thai J Pharm Sci 2000, 24, 27-36.
Key words : chiral stationary phase, salbutamol, solid phase extraction, fluorescence

A solid phase extraction procedure followed by a fluorescence HPLC assay was developed for the determination of salbutamol enantiomers in urine. The extraction method employing silica cartridge made in house, was proved to be able to eliminate the matrix in urines with over 98% recovery of salbutamol. In HPLC analysis, organic mobile phase containing hexane/dichloromethane/methanol/trifluoroacetic acid 60:35:5:0.1 by volume) with urea-Pirkle type chiral stationary was employed to resolve salbutamol enantiomers. In this paper (-)-phenylephrine was used as an internal standard. Baseline resolution was achieved with enantioselectivity (a) and enantiomeric resolution (R_s) of 1.37 and 2.0, respectively. Concentration of each salbutamol enantiomer could be measured down to 0.25 ng ml^-1 from 1 ml urine sample.The calibration curve was linear from 0.5 to 10 ng ml^-1. Furthermore, stability studies revealed that salbutamol in urine samples were stable if stored at -20 ^oC for 6 months. However, if the storage condition was at 8 ^oC, salbutamol degraded about 5% after one month.

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