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Cat. No.: HY-101833
Handling Instructions

YM-264 is a selective, potent and orally active platelet-activating factor (PAF) antagonist with a pKi value of 8.85 for rabbit platelet membranes.

For research use only. We do not sell to patients.

YM-264 Chemical Structure

YM-264 Chemical Structure

CAS No. : 131888-54-5

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  • Biological Activity

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YM-264 is a selective, potent and orally active platelet-activating factor (PAF) antagonist with a pKi value of 8.85 for rabbit platelet membranes.

IC50 & Target

pKi: 8.85 (PAF, rabbit platelet membranes)[1].

In Vitro

The anti-platelet-activating factor effect of YM-264 is examined in vitro. YM-264 inhibits [3H] platelet-activating factor binding to rabbit platelet membranes with a pKivalue of 8.85. YM-264 inhibits the platelet-activating factor-induced human, rabbit and guinea-pig platelet aggregation with pA2 values of 8.68, 8.33 and 8.14, respectively[1].

In Vivo

There are no significant differences in baseline airway responsiveness between control and YM-264 treated groups. Airway hyperresponsiveness induced by antigen exposure is significantly inhibited by the administration of YM-264. The baseline Rrs is 0.40 (0.02) cm H2O/mL/s in the control group (n=6). In the YM-264 treated groups, the baseline Rrs is 0.39 (0.01) and 0.36 (0.01) cm H2O/mL/s at a doses of 1 mg/kg (n=5) and 3 mg/kg (n=6), respectively. The Rrs during the IAR significantly increase from baseline to 0.92 (0.10) cm H2O/mL/s in control (p=0.0002), 0.81 (0.12) in YM-264 1 mg/kg (p=0.01), and 1.06 (0.29) in YM-264 3 mg/kg (p=0.048). Reelevation of Rrs in the late phase is observed in the control group after antigen challenge. At this phase, Rrs significantly increase to 0.72 (0.10) cm H2O/mL/s (p=0.0101) from the baseline (0.40) at 6 h after the exposure of antigen. In contrast, YM-264 at the doses of 1 and 3 mg/kg show significant inhibition of reelevation of Rrs as compared with control. YM-264 inhibit the eosinophil infiltration dose dependently[2].

Animal Administration

Guine Pigs[2]
Male Hartley guinea pigs weighing approximately 300 g are sensitized. The animals are fixed in position with the nose and mouth directed toward the center of the cylinder. Ovalbumin (10 mg/mL) is administered daily for 10 min. On the ninth or tenth day, all of the animals exhibit asthmatic symptoms. Two booster inhalations of AO (10 mg/mL) are subsequently given to the guinea pigs for 5 min at weekly intervals. Forty-five animals are randomized into three experimental groups by the order of their capture from shipping crate. Each group is further divided into three subgroups for control, YM-264 (1 mg/kg) and YM-264 (3 mg/kg). One week after the second booster inhalation, 16 animals for AH experiment are randomly divided into three subgroups for control and YM-264 treatment (1 and 3 mg/kg), and they are exposed to aerosolized OA (10 mg/mL) for 5 min. A dose of 1 or 3 mg/kg of YM264 is administered orally 30 min before and again, 3 h after the exposure to OA. The control group receives 0.5% methylcellulose in the same volume as YM-264[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Molecular Weight









Please store the product under the recommended conditions in the Certificate of Analysis.


Room temperature in continental US; may vary elsewhere

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Cat. No.: HY-101833