MA-2029 is selective for the motilin receptor over various other receptors and ion channels. MA-2029 is a selective and competitive motilin receptor antagonist (IC50=4.9 nM). MA-2029 may be useful for gastrointestinal disorders associated with disturbed gastrointestinal motility.

Motilin receptor:4.9 nM

MA-2029 concentration-dependently inhibits the binding of [125I]motilin to motilin receptors in a homogenate of rabbit colon smooth muscle tissue and membranes of HEK 293 cells expressing human motilin receptors. The pKi of MA-2029 is 8.58±0.04 in the rabbit colon homogenate and 8.39 in the HEK 293 cells. MA-2029 (1 to 30 nM) competitively inhibits motilin-induced contractions in isolated rabbit duodenal longitudinal muscle strips, with a pA2 value of 9.17±0.01. Contractile responses to acetylcholine and substance P are unaffected even at 1 μM of MA-2029 .

MA-2029 (10 mg/kg; p.o.) treatment displays that the t1/2 is 2 hours. The inhibition is significant at 30 min after administration of 3 mg/kg or more and at 4 h after administration of 10 mg/kg or more (MA-2029), so the administration of 10 mg/kg or more causes inhibitory effects from 30 min or less to at least 4 h after administration. MA-2029 (0.3-3 mg/kg; p.o.) dose-dependently suppresses the number of abdominal muscle contractions induced under the same conditions and cause significant inhibition at 3 mg/kg .