Compound 8 [PMID: 25898023] is a selective inhibitor of Rho kinase (ROCK) activity that was developed for the treatment of ocular inflammation [1
]. In an effort to reduce unintended systemic ROCK-associated side effects and maximise local effects, it was designed to be rapidly converted to an inactive metabolite in the systemic circulation. Compounds of this type are known as 'soft' drugs. Specifically, compound 8 contains an ester group that is hydrolysed by blood esterases to an inactive carboxylic acid metabolite (8M).
Amakem Ophthalmics have a 'soft' ROCK inhibitor AMA0076 that has been shown to reduce intraocular pressure in a rabbit model of glaucoma [4
], and which has completed Phase 2 clinical evaluation in glaucoma/ocular hypertension (NCT01693315
). The structure of AMA0076 has not been formally disclosed, but it appears to be derived from the same chemical scaffold as compound 8.