is hydroxyl, a halide such as Cl, I or Br or an ester group which can be prepared from a hydroxyl group such as an alkyl, phenyl, benzyl or substituted alkyl, phenyl or benzyl group, including activated ester groups such as a tosyl group, mesyl group or related activating groups. [0063] The term ???biodegradable??? relates to the characteristic whereby a polymer will degrade in the body.