MK-0974(Telcagepant) is a highly potent, selective, and orally bioavailable CGRP receptor antagonist with Ki values of 0.77 nM and 1.2 nM for human and rhesus CGRP receptors respectively; displays >1500-fold lower affinity for the canine and rat receptors

MK-1064 is a selective orexin 2 receptor antagonist (2-SORA) for the research of insomnia.

MK-2894 is a highly potent and selective second generation EP4 antagonist.

MK-3207 is a potent and orally bioavailable CGRP receptor antagonist (IC50= 0.12 nM; Ki value= 0.024 nM); highly selective versus human AM1, AM2, CTR, and AMY3.

MK-3697 is a third insomnia drug, currently being developed by Merck. MK-3697 is a potent and selective Orexin receptor antagonist with Ki = 0.95 nM.

MK-571 is a selective, orally active CysLT1 receptor antagonist.

MK-6892 is a highly potential GPR109A agonist with Ki value of 4.0 nM.

MK-7246 is a potent and selective CRTH2 antagonist with a Ki of 2.5±0.5 nM.

MK-8318 (MK8318) is a potent, selective, orally available CRTh2 receptor antagonist with Ki of 5 nM, shows nM potency in functional assay (cAMP IC50=8 nM, β-Arrestin IC50=3.5 nM.

ML-109 is a potent and full thyroid stimulating hormone receptor (TSHR) agonist, with an EC50 of 40 nM.

ML-224 (ANTAG3) is a selective TSH receptor antagonist inhibits stimulation of thyroid function in female mice.

MLR-1023 is a chemical compound which inhibits acid secretion in animal models and also acts as a bronchodilator in histamine-challenged animals.

MLS6585 is a novel positive allosteric modulator of the D1 dopamine receptor, potentiatse dopamine-stimulated G-protein- and β-arrestin-mediated signaling and increase the affinity of dopamine for the D1 receptor with low micromolar potencies..

Montelukast belongs to a group of medications known as leukotriene receptor antagonists.

Mozavaptan (OPC31260) is a orally effective, nonpeptide vasopressin V2 receptor antagonist with an IC50 of 14 nM.

MRE-269 is an active metabolite of selexipag, and acts as a selective IP receptor agonist.

MRS1186 is a potent and selective human Adenosine A3 receptor (hA3AR) antagonist, with a Ki of 7.66 nM.

MRS2578 is a potent P2Y6 receptor antagonist with IC50 of 37 nM, exhibits insignificant activity at P2Y1, P2Y2, P2Y4,and P2Y11 receptors.

MSX-122 is a n orally bioavailable inhibitor of CXCR4 with potential antineoplastic and antiviral activities.

MSX-130 is CXCR4 Antagonist.

MTEP Hcl is a potent, selective and non-competitive mGlu5 antagonist with IC50 and Ki of 5 nM and 16 nM, respectively.

Naftopidil is an α-1-Adrenergic receptor antagonist and an antihypertensive.