Table 4.

Advantages and disadvantages of controlled drug delivery systems.

Advantages of Controlled DDS	Disadvantages of Controlled DDS
Controlled or defined drug release	Possible toxicity of materials used
Target specificity	Dose dumping
Long residence of drug	Invasive procedure to implant or remove the system
Protection from metabolism by enzymes/chemicals	Uptake by RES reduces efficacy
Improved bioavailability	Poorer IVIVC
Low dosing frequency	Limited standards
Better patient compliance	Higher manufacturing cost