SB224289 is a selective antagonist of 5-HT1B receptor with pKi of 8.2. It is a centrally active following oral administration in vivo. SB224289 displays 60-fold selectivity over 5-HT1D, 5-HT1A, 5-HT1E, 5-HT1F, 5-HT2A and 5-HT2C receptors in radioligand
SB 243213 hydrochloride is an orally active, selective and high-affinity antagonist of 5-hydroxytryptamine (5-HT)2C receptor(pKi of 9.37 and a pKb of 9.8).It has improved anxiolytic profile and has the potential for schizophrenia and motor disorders.