Diacetylmorphine, or heroin, was first synthesized from morphine in 1874. It is formed by simply adding two acetyl groups. Heroin is around three times more potent than morphine. Its increased lipid solubility allows heroin to cross the blood-brain barrier more quickly. The drug is reconverted back to morphine before it binds to brain-tissue receptors.
Pure heroin is a white, odourless powder with a bitter taste.
This is because of impurities left from the manufacturing process or the presence of additives. Heinrich Dreser, in charge of drug development at Bayer, tested the new semi-synthetic drug on animals, humans, and most notably himself. He was impressed. Dreser pronounced heroin an effective treatment for a variety of respiratory ailments, especially bronchitis, asthma and tuberculosis. Commercial production of heroin began in 1898.