ROS 234 is a highly effective H3 antagonist, demonstrating a strong binding affinity (pK B) of 9.46 for the Guinea-pig ileum H3 receptor and a pKi of 8.90 for the Rat cerebral cortex H3 receptor. Additionally, it exhibits an ex vivo ED50 of 19.12 mg kg (ip) in the Rat cerebral cortex. It should be noted that ROS 234 demonstrates limited central access, as reported in [1] and [2].