Type 4 cyclic nucleotide phosphodiesterases (PDE4s), which are highly expressed in neutrophils and monocytes, selectively inactivate the second messenger cAMP by hydrolyzing the phosphodiester bond, producing AMP. Inhibition of PDE4 activity has been examined in the context of treating asthma, chronic obstructive pulmonary disease, and as a general modulator of inflammation. ML-030 is a triazolothiadiazine that inhibits PDE4 in a cell-based cyclic nucleotide-gated cation channel biosensor assay with an EC50 value of 18.7 nM. Among the PDE4 isoforms, ML-030 displays selectivity for inhibiting PDE4A (IC50 = 6.7 nM) over PDE4B1, PDE4B2, PDE4C1, and PDE4D2 (IC50 = 48.2, 37.2, 452, and 49.2 nM, respectively).
![3-(2,5-dimethoxyphenyl)-6-(3,4-dimethoxyphenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine](https://www.chemicalbook.com/CAS/20180703/GIF/1013750-77-0.gif)