A potent, selective and orally active receptor antagonist of leukotriene D4, verlukast (MK-571), was discovered and developed from a styrylquinoline lead structure based on a hypothetical model of the leukotriene D4 receptor. MK-571 blocks the action of LTD4 in animals and man, and is effective in a number of animal models of antigen-induced bronchoconstriction at plasma concentration at or below 2 ug/mL. MK-571 also blocks antigen-induced asthmatic responses in man. MK-571 is a potent and selective leukotriene D4 (LTD4) antagonist and ABCC multidrug resistance protein 1(MRP1) inhibitor. The cysteinyl leukotrienes (CysLTs), LTC4, LTD4, and LTE4, mediate their actions through two distinct G-protein coupled receptors. LTD4 is the preferred ligand for the CysLT1 receptor, whereas LTC4 and LTD4 bind with approximately equal affinity to the CysLT2 receptor. MK-571 is a selective, orally active CysLT1 receptor antagonist. It blocks the binding of LTD4, but not LTC4, to human and guinea pig lung membranes with Ki values of 0.22 nM and 2.1 nM, respectively. MK-571 effectively blocks LTD4 activation of recombinant human and mouse CysLT1 receptors but is ineffective at blocking LTC4 or LTD4 activation of the recombinant human or murine CysLT2 receptors.

Cathine, known as D-norpseudoephedrine, is a psychoactive drug of amphetamine class, found naturally in Catha edulis (khat). It is a norepinephrine and dopamine releasing agent, and has thermogenic and anorectic effect. In the United States, cathine is classified as a Schedule IV controlled substance. Cathine hydrochloride is used as an appetite suppressant during the first few weeks of dieting to help establish new eating habits.

Roxindole (EMD-49,980) is a dopaminergic and serotonergic drug which was originally developed for the treatment of schizophrenia. Roxindole has also been investigated as a therapy for the major depressive disorder, Parkinson's disease, and prolactinoma. Roxindole is dopamine autoreceptor-selective agonistic drug with high affinity to D2-like receptors and with much lower affinities to D1-like, % and ol2, muscarinic and 5HT 2 receptors. Additionally, Roxindole exerts 5HT uptake inhibition and 5HT1A agonistic effects. The bioavailability of Roxindole has been estimated at 5% due to a high first-pass metabolization. On the other hand, in 14C distribution studies, Roxindole has crossed the blood-brain barrier readily and the brain concentrations at all intervals have been much higher than corresponding plasma levels. In clinical trials, Roxindole ‘s antipsychotic efficacy was only modest but it was unexpectedly found to produce potent and rapid antidepressant and anxiolytic effects. However, the clinical development of Roxindole was discontinued.

Efrotomycin (ET) is an antibiotic obtained by the incubation of Nocardia lacamduranns, and composed of 4 components: Efrotomycin A1, Efrotomycin A2, Efrotomycin B1, and Efrotomycin B2. Although its antibacterial spectrum is narrow, ET has an antibacterial effect on part of the Grampositive bacteria and on treponema, and has a growth promoting effect on pigs etc. ET is a pure-grade antibiotic that was designated as a feed additive. Under the brand name Producil Efrotomycin was indicated for increased rate of weight gain when incorporated into complete swine feeds at 3.6 to 14.5 g/ton. This antibiotic is a potent inhibitor of bacterial protein synthesis by interfering with peptide transfer reactions associated with the elongation factor Tu.

Nimorazole is an antimicrobial with activity against anaerobic bacteria and protozoa. Its actions and properties are similar to metronidazole. It has also been used in trials studying the treatment of Hypoxia, Radiotherapy, Hypoxic Modification, Gene Profile, Gene Signature, and Head and Neck Squamous Cell Carcinoma, among others. Azanta is developing, nimorazole, as an oral hypoxic radio-sensitiser for the treatment of patients with head and neck cancer who are undergoing radiotherapy. Previously, nimorazole has been approved for use as an anti-protozoal agent and has been launched worldwide. Nimorazole, for the treatment of head and neck cancer patients undergoing radiotherapy received orphan designation by EMA in 2011.

Vaniprevir (MK-7009) is an non-covalent competitive macrocyclic inhibitor of Hepatitis C virus NS3/4A protease genotype 1a and 1b proteases at subnanomolar concentrations with modestly shifted potency against genotype 2a and 2b proteases at low nanomolar concentrations. Merck & Co. developed vaniprevir in combination with standard therapy for the twice-daily treatment of hepatitis C virus infections. The product has been launched in Japan under name VANIHEP, and Merck reported in its 2014 annual report that the product will only be available in this region.

Ivermectin B1B (dihydroavermectin B1b) is the minor component (<10%) of the commercial anthelmintic, ivermectin. Members of the avermectin/milbemycin anthelmintic class exert their anthelmintic effects by binding to glutamate-gated chloride channels expressed on nematode neurons and pharyngeal muscle cells. The avermectin/milbemycins are also potent insecticides. In vitro, the B1b (25-isopropyl) analog is slightly more potent than the 25-sec-butyl (B1a) analog as an inhibitor of nematode larval development and paralysis, and also a more sensitive probe for ivermectin resistance.

Etoricoxib is a selective COX-2 inhibitor, which is approved in Europe for the treatment of inflammatory disorders such as osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, acute pain conditions, gout and postoperative dental surgery pain.

Eprinomectin is 4"-deoxy-4"-epiacetylamino-avermectin B1. It is a semi-synthetic member of the avermectin family of macrocyclic lactones and consists of a mixture of two homologous components, B1a (not less than 90%) and B1b (not more than 10%), which differ by a single methylene group at C26. Eprinomectin is a member of the macrocyclic lactone class of endectocides which have a unique mode of action. Compounds of the class bind selectively and with high affinity to glutamate-gated chloride ion channels which occur in invertebrate nerve and muscle cells. This leads to an increase in the permeability of the cell membrane to chloride ions with hyperpolarization of the nerve or muscle cell, resulting in paralysis and death of the parasite. Compounds of this class may also interact with other ligand-gated chloride channels, such as those gated by the neurotransmitter gamma-aminobutyric acid (GABA). Molecular studies indicate that these drugs interact strongly not only with ligand-gated ion channels, the mode-of action receptors of nematodes and arthropods, but also with efflux ABC transporters. The margin of safety for compounds of this class is attributable to the fact that mammals do not have glutamate-gated chloride channels, the macrocyclic lactones have a low affinity for other mammalian ligand-gated chloride channels and they do not readily cross the blood-brain barrier. IVOMEC EPRINEX (eprinomectin) Pour-On is indicated for the treatment and control of gastrointestinal roundworms (including inhibited Ostertagia ostertagi), lungworms, grubs, sucking and biting lice, chorioptic and sarcoptic mange mites, and horn flies in beef and dairy cattle of all ages, including lactating dairy cattle.

Bamaluzole, an anticonvulsant compound, is an agonist of a GABA receptor.