Yep: as someone with a chemistry background, synthesis is the easy part.
Purification and analysis? That's the hard part.
Not getting screwed by additives, coatings or contamination? Thats what the big bucks in lab gear cost (i.e. a metered dispensing pump comes with a list of every element which touches the dispensed fluid).
I'd be hesitant to put anything mixed in a DIY device with off the shelf peristaltic pumps into my body without some additional analysis.
If something like automated analysis was a possibility, then maybe this would be more alluring.