E.g., 14 mg[sup]-1[/sup] day[sup]-1[/sup].
How do you pronounce it? What does it mean? Is it simply milligrams per day? Why the “-1”? Thank you.
“per milligram per day”
An exponent of -1 means reciprocal ( x[sup]-1[/sup] = 1 / x )
This is a little weird - I’d expect mg day[sup]-1[/sup] without the (-1) on mg.
You’d read it as “per milligram per day”. The notation x[sup]-1[/sup] is another (and often more convenient) notation for 1/x.
It’snot so weird. I’ve seen it more often as mg of a drug per kilogram of body weight per day, or X mg kg[sup]-1[/sup] day[sup]-1[/sup].
Ah, it makes sense now! My example should have read “14 mg kg[sup]-1[/sup] day[sup]-1[/sup]”, so no wonder it looked weird. Sorry about the error, and thank you both for your help.