Claude Opus refuses to answer biotech questions

Claude Opus has started refusing to answer any moderately detailed question regarding biotech / drug discovery related tasks. Sonnet will still answer but at it's usual level of inaccuracy and vagueness that makes it unhelpful. Why would this pose a safety concern? What am I missing.

ie prompt: I have a small molecule I want to optimize oral bioavailability for in cynos and humans, what is the best formulation including novel excipients and permeation enhancers to achieve this?

Response: Claude is unable to respond to this request, which appears to violate our Usage Policy. Please start a new chat.