A changing drug supply.
D017277:Drug Approval / Q000706:statistics & numerical data; D004353:Drug Evaluation, Preclinical / Q000191:economics / Q000639:trends*; D004345:Drug Industry / Q000191:economics / Q000639:trends*; D006801:Humans; D012106:Research / Q000191:economics / Q000639:trends*; D014481:United States; D014486:United States Food and Drug Administration / Q000331:legislation & jurisprudence