Table 1.

Fundamental characteristics of a targeted drug delivery system

Features	Effect on drug delivery system
The rate of carrier delivery (encapsulated with the drug) to the targeted sites	• An adequate amount of a drug should be delivered to the desired sites • The free drug should reach a particular concentration in the targeted area
The rate of carrier elimination (encapsulated with the drug) from the targeted sites	• The drug should remain in the desired area for a sufficient time • Elimination process of carrier drug conjugate should not be faster than the delivery process
The duration between drug release and drug removal in the targeted sites	• The drug should retain a specific concentration in the targeted tissues for sufficient time to act on it
The rate of drug release at non-targeted sites	• Releasing the drug at non-targeting tissue will reduce the amount of drug delivered to the intended areas • The systematic toxicity will increase
The rate of carrier drug conjugate removal from the body	• The rate of drug elimination from the circulation system should be faster than its transition rate from the targeted tissues to the central compartment of the body