Targeting implies that the concentration of a
substance is increased in the vicinity of a target.
A selectivity of the targeting vehicle between
target and non-target is required.

When targeting is achieved, it is normal that the
targeting vehicle releases the substance.

For oral delivery, release properties are adjustable by
changes in pH of the gastric tract or by enzymatic activity.

An example of a product, where both drug targeting
and drug release are used, is described at the
website of Microbionical.
      Controlled release    
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