Formation of inclusion-complexes between cyclodextrins, as mobile-phase additives in RPTLC, and fluoxetine, norfluoxetine, and promethazine

Inclusion complex formation and the potential separation of racemates of fl uoxetine (FL) and norfluoxetine (NR), and of promethazine (PR) and its stru ctural isomer isopromethazine (i-PR), have been investigated by reversed-ph ase thin-layer chromatography with hydroxypropyl-beta-cyclodextrin (HP-beta -CD) and beta-cyclodextrin (beta-CD) as mobile-phase additives, The results were compared with those from analogous studies in HPLC and capillary elec trophoresis, Although the high affinity of the drugs for the stationary pha se limited the selection of suitable chromatographic conditions, complex fo rmation was evident with both types of cyclodextrin for all three drugs. Us e of HP-beta-CD enables the successful separation of the enantiomers of FL and NL and the positional isomers of promethazine.