The MIC against H. pylori isolates ranged from 0.002-0.032 μg/mL (0.01-0.17 μM) in the agar dilution assay. HPi1 is effective against the clarithromycin-resistant strains ARHp172 (MIC of 0.004–0.016 μg/mL) and ARHp246 (MIC of 0.008–0.032 μg/mL).
HPi1 has some activity against the Bacteroides species , but at concentrations at least 18- fold higher than the H. pylori MIC. More potent activity is detected for Campylobacter jejuni with an MIC of 0.3 μg/mL.
HPi1 has good physicochemical and pharmacological properties, including determining the aqueous solubility (19 μg/mL), human plasma protein binding (93% bound), stability with human liver microsomes (T 1/2 of 1.3 hours) and the ability to passively permeate membranes.
