Single injection of ONO-1301-loaded PLGA microspheres directly after ischaemia reduces ischaemic damage in rats subjected to middle cerebral artery occlusion.

ONO-1301 was developed as a novel long-acting prostacyclin agonist with thromboxane synthase inhibitory activity. In this study, we investigated the therapeutic time window of oral ONO-1301 and the effect of a single subcutaneous injection of ONO-1301-loaded poly(lactide-co-glycolide) (PLGA) microspheres (ONO-1301 PLGA MS) on infarction volume, functional deficits and plasma ONO-1301 levels following a 1 h middle cerebral artery occlusion (MCAO) in rats. Rats were treated with ONO-1301 (3 mg/kg) orally twice-daily starting 1 (directly), 6 or 24 h after MCAO. Rats received a single subcutaneous injection of ONO-1301 PLGA MS (10 mg/kg) directly after MCAO. Neurological scores were evaluated directly after, 1 and 6 h, 1, 2, and 3 days after MCAO. Infarct volume, oedema and plasma ONO-1301 levels were measured three days after MCAO. Neurological scores, oedema and infarct volume were all significantly improved in rats repeatedly treated with oral ONO-1301 and subcutaneous ONO-1301 PLGA MS directly after MCAO. Plasma ONO-1301 levels were significantly lower in rats treated directly after MCAO (either with ONO-1301 or ONO-1301 PLGA MS) than in rats treated 6 h or 24 h after MCAO. ONO-1301 PLGA MS subcutaneous treatment directly after MCAO showed a neuroprotective effect as well as oral ONO-1301. This treatment should be clinically more convenient than ONO-1301 oral administration since it is delivered as a single treatment after MCAO.