Thiazinamium (chloride)

Thiazinamium (chloride) possesses potent anticholinergic and antiallergic activity and inhibits TxB2 synthesis with IC₅₀ value of 0.2 µM. Thiazinamium (chloride) is structurally similar to H-1 antagonists Promethazine (HY-B1296). Thiazinamium (chloride) stimulates the phosphatidylcholine secretion in adult rat type II pneumocytes^[1][2]. IC50 & Target:IC50: 0.2 µM (TxB2 synthesis)^[1] In Vitro:TxB2 synthesis by resting macrophages is inhibited by thiazinamium chloride and promethazine in a dose-dependent manner. Thiazinamium chloride inhibits TxBz synthesis but had no effect on the ingestion of zymosan particles. In contrast, chlorpromazine inhibits phagocytosis but not TxBz synthesis except at lo^-3 M. Under the condition where indomethacin, a nown cyclooxygenase inhibitor, is inhibitory, promethazine but not thiazinamium chloride inhibits TxB2 synthesis from exogenous arachidonic acid. Treatment of macrophages with promethazine and chlorpromazine but not thiazinamium chloride results in a reduction in the oxidative burst during phagocytosis. Furthermore, the ability of thiazinamium chloride to selectively inhibit arachidonic acid metabolism may contribute to its bronchodilator/antiallergic activity^[1].