The geometric mean ratios ( MPH-MLR/IR methylphenidate -LSB- @ % CI -RSB- ) of log-transformed area under the plasma drug concentration-time curve to the last measurable observation ( day @ : @ -LSB- @-@ @ -RSB- ; day @ : @ -LSB- @-@ @ -RSB- ) , and area under the plasma drug concentration extrapolated to infinity ( day @ : @ -LSB- @-@ @ -RSB- ; day @ : @ -LSB- @-@ @ -RSB- ) were within the @-@ % bioequivalence range .