RS-25344 hydrochloride is a selective cAMP-phosphodiesterase 4 (PDE 4; PDE IV) inhibitor with an IC 50 of 0.28 nM in human lymphocytes. RS-25344 hydrochloride has only weak inhibitory effects on PDE I, II, III (IC 50 of >100 μM, 160 μM, 330 μM, respectively). RS-25344 hydrochloride has anti-inflammatory, memory- and cognition enhancing, and antineoplastic effects In Vitro RS-25344 hydrochloride (0-10 μM) is a potent inhibitor of sperm PDE activity, with an effective concentration of 0.3 nM and reaching maximum inhibition in the range of 100 nM. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo RS-25344 hydrochloride (5 mg/kg; i.p.; twice daily for 72 h) results in significant increases in stomach weights in wild type C57BL/6 mice. RS-25344 hydrochloride (1 mg/kg; i.p.; 30 min prior to food bolus) increases gastric retention in mice. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:PDE Ⅳ 0.28 nM (IC 50 ) PDE Ⅰ >100 μM (IC 50 ) PDE Ⅱ 160 μM (IC 50 ) PDE Ⅲ 330 μM (IC 50 )