High Quality Content by WIKIPEDIA articles! SB-271,046 is a drug which is used in scientific research. It was one of the first selective 5-HT6 receptor antagonists to be discovered, and was found through high-throughput screening of the SmithKline Beecham Compound Bank using cloned 5-HT6 receptors as a target, with an initial lead compound being developed into SB-271,046 through a structure-activity relationship (SAR) study. SB-271,046 was found to be potent and selective in vitro and had good oral bioavailability in vivo, but had poor penetration across the blood-brain barrier, so further SAR work was then conducted, which led to improved 5-HT6 antagonists such as SB-357,134 and SB-399,885.