Purity ~95% (HPLC). A cell-permeable, competitive Acidic Mammalian Chitinase (AMCase) Inhibitor (IC50=0.92uM and Ki=0.42uM for hAMCase, and IC50=2.2uM for mAMCase, in vitro) that demonstrates 20-fold selectivity for hAMCase over hCHIT1. It is shown to decrease chitinase enzymatic activity (5mg/kg, i.p.) in the lungs of control PBS- and OVA-challenged mice. Furthermore, it attenuates lung chitinase activity, reduces eosinophil influx, and improves ventilatory function, in vivo, in a murine model of allergic inflammation. It also causes neutrophilia in the lungs of OVA-challenged mice. Formula: C16H18N8O4 Molecular Weight: 386.4 Solubility: DMSO (5mg/ml, clear, nearly colorless solution)