Pharmacology of montelukast sodium (Singulair™), a potent and selective leukotriene D₄receptor antagonist

Abstract

Montelukast sodium (Singulair), also known as MK-0476 (1-(((1(R)-(3-(2-(7-chloro-2-quinolinyl)-(E)-ethenyl)phenyl)(3-2-(1- hydroxy-1-methylethyl)phenyl)propyl)thio)methyl)cyclopropane) acetic acid sodium salt, is a potent and selective inhibitor of [3H]leukotriene D4 specific binding in guinea pig lung (Ki 0.18 +/- 0.03 nM), sheep lung (Ki 4 nM), and dimethylsulfoxide-differentiated U937 cell plasma membrane preparations (Ki 0.52 +/- 0.23 nM), but it was essentially inactive versus [3H]leukotriene C4 specific binding in dimethylsulfoxide-differentiated U937 cell membranes (IC50 10 microM) and [3H]leukotriene B4 specific binding in THP-1 cell membranes (IC50 40 microM). Montelukast also inhibited specific binding of [3H]leukotriene D4 to guinea pig lung in the presence of human serum albumin, human plasma, and squirrel monkey plasma with Ki values of 0.21 +/- 0.08, 0.19 +/- 0.02, and 0.26 +/- 0.02 nM, respectively. Functionally, montelukast antagonized contractions of guinea pig trachea induced by leukotriene D4 (pA2 value 9.3; slope 0.8). In contrast, montelukast (16 microM) failed to antagonize contractions of guinea pig trachea induced by leukotriene C4 (45 mM serine-borate), serotonin, acetylcholine, histamine, prostaglandin D2, or U-44069. Intravenous montelukast antagonized bronchoconstriction induced in anesthetized guinea pigs by i.v. leukotriene D4 but did not block bronchoconstriction to arachidonic acid, histamine, serotonin, or acetylcholine. Oral administration of montelukast blocked leukotriene D4 induced bronchoconstriction in conscious squirrel monkeys, ovalbumin-induced bronchoconstriction in conscious sensitized rats (ED50 0.03 +/- 0.001 mg/kg; 4 h pretreatment), and also ascaris-induced early and late phase bronchoconstriction in conscious squirrel monkeys (0.03-0.1 mg/kg; 4 h pretreatment). A continuous i.v. infusion of montelukast (8 micrograms.kg-1.min-1) resulted in a 70% decrease in the peak early response and a 75% reduction of the late response to ascaris aerosol in allergic conscious sheep. Montelukast, a potent and selective leukotriene D4 receptor antagonist with excellent in vivo activity is currently in clinical development for the treatment of asthma and related diseases.

Fracture healing and lipid mediators

“…Montelukast antagonizes cysteinyl leukotriene receptor 1 and is commonly used to treat asthma. 44,45 Mice treated with montelukast daily (1.5 mg kg À 1 , gastro-intestinal gavage) showed increased fracture callus cartilage amounts similar to what had been observed in 5-LOnull mice or in rats treated with a 5-LO inhibitor. 9,13,46 In contrast, when rats were treated with montelukast daily (1 mg kg À 1 , intraperitoneal injection), no effect on tibial fracture healing was observed.…”

Shortening of the Induction Period of Allergic Asthma in Cynomolgus Monkeys by Ascaris suum and House Dust Mite

“…Non-human primate models could reduce these concerns (1 -9). Thus far, although wildcaught cynomolgus monkeys (10 -13) and squirrel monkeys (14) sensitive to inhaled Ascaris suum allergen had been used, these wild-caught monkeys are not currently available. Recently, several studies showed that sensitization of monkeys with allergens could elicit allergen-specific IgE production (9) and allergic asthma symptoms upon allergen provocation (15,16).…”

Characterization of Mouse Cysteinyl Leukotriene Receptors mCysLT1 and mCysLT2

“…Most of the biological reactions of cysteinyl LTs including bronchospasm, plasma exudation, vasoconstriction, mucus secretion, and eosinophil recruitment are mediated through interaction with CysLT 1 (11). CysLT 1 antagonists, montelukast (Singulair TM ) (12,13), zafirlukast (Accolate TM ) (14), and pranlukast (Onon TM ) (15) are currently used clinically for the treatment of bronchial asthma and allergic rhinitis. Human CysLT 1 , human CysLT 2 , and mouse CysLT 1 were recently cloned and characterized (16 -21).…”