Oh, it's all good.
My philosophy is that anything that is possible is possible for a PC...for a price.
For example, wanna overthrow the emperor? No problem. Get you diplomatic skills up high enough, convince a few hundred worlds to revolt, and there your are...you probably want to have someone in your party who is the equivalent of Sun Tsu and Von Clausewitz all rolled into one managing your military, but those are easy to find, right?
Or, just assassinate him. I'd expect there'd be a few dozen very high DC rolls to make to get past his security. And after that, there would be the problem of succession...I'd expect his heirs just wouldn't roll over and let you be the boss. Details, details.
So, if it's physically possible to make anagathics in the T20 universe, it's possible for a character or a group of characters or a group of characters supervising a large number of employees to make them. Now, what skills do they need? I'd expect that Medical/5 wouldn't quite do. What facilities do they need? I doubt a Cr500 chemistry set would suffice. How much labor is involved? For a single dose, the key question is if one person, given all the necessary skills, materials, and facilities, could make a dose in a month. I would expect the answer is yes, since we're talking about something you could hold in your hand. But making the first batch might take years of research. Consider, how long does it take to make a light bulb? A few minutes, given all the facilities. How long did it take Edison to make the first light bulb? Months. How long would it take you to make a light bulb from scratch? It would take you a few days to set up the machinery to make the first one, then you could just crank them out. I'd think it would be the same with anagathics, although the Cr200,000 price implies a large amount of tweaking with some very sophisticated equipment to get it just right.
Likewise, if you wanted to make dozens, let alone hundreds of doses a month, maybe a ship-sized laboratory wouldn't do. You'd need several dozen highly skilled workers, all highly paid professionals, to do the tweaking, and each one of them would need space to work. They probably couldn't all share the same mass spectrometer and still get their month's work done, so you'd have to provide them with several (and several centrifuges, and several gene sequencers, and several....you get the point).
But, to get back to my original question, given that anyone with Cr200,000 and the right contacts can score a dose (well, if they're in a place where anagathics are available), the drugs shouldn't be impossible to manufacture, just very difficult. Even at 1/3 the price for raw materials, bringing in Cr66,667 credits/character/month isn't exactly a trivial task, and I'd expect that spending enough time in the lab to make them wouldn't leave as much time for adventuring as most characters would like. And, if the big pharmaceutical companies get wind of the fact that someone is cutting into their boutique market for ultra-high priced drugs, they may get cranky and do something about it.
Just some of my thoughts on the subject.