Biodegradablity and biocompatibility

Biodegradablity and biocompatibility

Biodegradability refers to the ability of the biological systems, such as the human body, to degrade and eliminate the polymer. This is important to ensure that any polymer administered as a part of a dosage form can break down into smaller pieces and be eliminated by the body, without causing undue toxicity of accumulation.

Biocompatibility of a polymer refers to the tolerance of the biological system, such as the human body, to the polymer. A biocompatible polymer is not sensed as foreign or harmful by the biological system, and the body does not mount an immune response against the polymer. This is criti-cal, for example, for administration of polymers as a part of implantable devices to prevent any adverse reactions. Thus, biocompatible polymers avoid chronic inflammation and long-term complications.

Most biodegradable polymers have hydrolysable linkages, namely ester, orthoester, anhydride, carbonate, amide, urea, and urethane, in their back-bones. Such linkages allow the biodegradable polymer to break down into metabolic products by hydrolysis or enzymatic action. Biodegradable poly-mers are reduced to soluble fragments that are either excretable or metabo-lized under physiological conditions.

Biodegradable biocompatible polymers are used to deliver a wide range of drugs to diseased tissues, often in a sustained-release dosage form for drug release and action over a prolonged period. Commercially available prod-ucts that use such polymers include Decaptyl^®, Lupron Depot^®, Zoladex^®, Adriamycin^® and Capronor^®.