Improvement of therapeutic index of phosphodiesterase type IV inhibitors as anti-Asthmatics

A new series of catechol hydrazines was synthesized and their structure–activity relationship (SAR) was analyzed for developing an effective phosphodiesterase 4 (PDE4) inhibitor as an anti-asthmatic drug candidate. Among the (E)-Analogues tested using in vitro assays, 5CC showed a strong PDE4 inhibitory activity and a significantly improved rolipram binding profile compared with rolipram, a prototype PDE4 inhibitor. Moreover, from in-vivo asthma model, we observed that (E)-Analogue 5CC had a good efficacy against guinea-pig respiratory tract inflammation and bronchoconstriction, along with a remarkably reduced emetic side effect, compared with rolipram. Conclusively, (E)-Analogue 5CC seems to be a promising candidate for the development of anti-asthmatic PDE4 inhibitors.