Microscale Experimentation vs. Preparative Synthesis during drug development

I'm trying to understand the drug development stages, techniques and procedures. My understanding on the subject:


**Microscale experimentation**


* Is used on early stages to find compounds reacting with some target
proteins/whatever
* Is done on a very small scale (< 1mg) since most of
the compounds are not going to react with the target
* Techniques: Combinatorial Chemistry


**Preparative Synthesis**


* Is done on later stages when we found a number of potentially useful compounds
* Is used to synthesise compounds in larger quantities (5-200mg) for further testing and possible conversions to other compounds with better characteristics (e.g. lower toxicity or better distribution). We need larger quantities because we will conduct a lot of experiments with these compounds down the road (including microscale experimentation?)
* Techniques: High-Throughput Chemistry


Could someone please correct and possibly extend my explanation?


