I am trying to create a case statement in t-sql to extract the various parts of this field into separate elements

Sample Data

VANCOMYCIN 1 GM - Route: INTRAVENOUS @ 08:45 By: GAM
ANCEF - Route: INTERVENOUS @ 11:15 BY GAM
ANCEF  2 GRAMS - Route: INTRAVENOUS @ 09:25 By: DR. HORNUNG

Basically, I need 4 separate elements, so for the first one it would be
Drug Name: VANCOMYCIN
Route: INTRAVENOUS
Time: 08:45
Give By: GAM

The only logic I can't really grasp is getting the Drug Name without the amount. The rest I have definable points I can utilize to include with the CHARINDEX feature. But since some of the drug names have an amount and some don't I'm stumped on that part.

Thanks for any help