A drug delivery process is the method for the administration of any pharmaceutical compound to achieve maximum therapeutic effect in humans and animals. It may be defined as a system comprising of Drug formulation, Medical device or dosage form /technology which carries the drug inside the body. A drug carrier is any substrate used in the process of drug delivery which serves to improve the selectivity, effectiveness and safety of drug administration. Drug Carriers are primarily used to control the release into systemic circulation. A wide variety of drug carrier systems have been developed and studied, each of which has unique advantages and disadvantages. The popular drug carriers include liposomes, microspheres, nanoparticles etc.