Analysis of information sources in references of the Wikipedia article "오피오이드" in Korean language version.
Opiate is the older term classically used in pharmacology to mean a drug derived from opium. Opioid, a more modern term, is used to designate all substances, both natural and synthetic, that bind to opioid receptors (including antagonists).
The lipid solubility of hydromorphone lies between morphine and fentanyl, but is closer to that of morphine.