Drug injection taking drugs, injection is favoured by some people as the full effects of the drug are experienced very quickly, typically in five to ten seconds. It also bypasses first-pass metabolism in the liver, resulting in higher bioavailability and efficiency for many drugs (such as morphine or diacetylmorphine/heroin; roughly two-thirds of which is destroyed in the liver when consumed orally) than oral ingestion would. The effect is that the person gets a stronger (yet shorter-acting) effect from the same amount of the drug. Drug injection is therefore often related to substance dependence. In a recreational context, the shorter, more intense "high"
Nanoparticles for drug delivery to the brain to target specific organs and tissues in the body, to carry DNA for gene therapy, and to deliver larger molecules such as proteins, peptides, and even genes. To manufacture these polymeric nanoparticles, the drug molecules are first dissolved and then encapsulated or attached to a polymer nanoparticle matrix. Three different structures can then be obtained from this process; nanoparticles, nanocapsules (in which the drug is encapsulated and surrounded by the polymer matrix), and nanospheres (in which the drug is dispersed throughout the polymeric matrix in a spherical form). One of the most important traits for nanoparticle delivery systems is that