A cell-permeable pyrazolo-napthalenyl urea compound that acts as a highly potent, slowly binding (IC₅₀ = 8 and 97 nM, respectively, against human p38α, respectively, with or without 2 h preincubation), but high affinity (t_1/2 of dissociation from human p38α = 23 h), p38-selective inhibitor by simultaneously targeting the ATP-binding site and an adjacent DFG-out conformation-specific allosteric cavity. It inhibits JNK2α2 and c-Raf-1 only at much higher concentrations (IC₅₀ = 98 nM and 1.4 µM, respectively) and displays little or no activity toward 10 other kinases (IC₅₀ >20 µM). Shown to inhibit LPS-induced TNF-α production in cultures in vitro (IC₅₀ = 18 and 780 nM using THP-1 cells and in human whole blood, respectively) and in mice in vivo (by 84% and 63%, respectively, with oral dosage of 30 mg/kg and 10 mg/kg).

Packaged under inert gas

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C.

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CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Regulatory Review (Z)