User blog comment:Xilinoc/Ch. 659 - There Will Be Frost/@comment-26091912-20160122035425/@comment-26091912-20160122103014

Hmm... maybe. I guess Ryuken was probably looking for a way to counteract Yhwach's ability to 'take' power. He already knows how to restore Quincy power, so it doesn't sound too implausible to suggest he was looking for a way to do the opposite. He may have told Uryu how while he was in the hospital during The Lost Substitute Shinigami Arc.

Could also explain why he's not interested in the Quincy and, well, probably detests them with every fibre of his being.