IDRA-21 is a positive AMPA receptor modulator.

Oral administration of IDRA 21 produced a highly significant improvement in the performance of a delayed matching-to-sample (DMTS) task by young adult rhesus monkeys.?The pattern of task improvement over the dose range 0.15-10 mg/kg was maintained to 48 hr after the single dose administration.?For sessions run after administration of the individualized Best Dose of IDRA 21, task accuracy for Long delay (most difficult) trials was increased by 34% of vehicle.?Animals were randomly assigned fixed doses of IDRA 21 to determine whether the positive mnemonic response could be maintained.?The repeated doses were separated by 3 days, thus allowing for potential cumulative effects.?IDRA 21 produced a gradual increase in task accuracy that was maintained on average above vehicle performance levels over an intermittent dosing schedule during a total period of 3 weeks.?A separate group of aged monkeys (>20 y) were, as a group, impaired (during vehicle testing) in DMTS performance efficiency relative to the young cohort.?IDRA 21 also improved task accuracy by aged rhesus monkeys over the same dose range, but the responses were not as robust as those exhibited by young animals.?Aged subjects also appeared to be more individually sensitive to drug dose, and they exhibited shorter task latencies than did the young group[1].