This could be my misunderstanding of the definition of "designer drugs" but I interpreted this as substances which mimic controlled substances but don't trigger drug classification or testing. Assuming this definition then this is something we wouldn't feel comfortable supporting regardless of the cash or demand. My understanding is that these substances are not tested in animal and human trials or approved by governing bodies like the FDA which are critical for the safety and efficacy of use.
Though please do correct me if I'm missing the use case you are referring to.
Though please do correct me if I'm missing the use case you are referring to.