This is a review of classical and novel concepts of drug delivery in particular diseases such as central nervous system disease, ophthalmic disease, cardiovascular disease, cancer and others. Nowadays, scientists are trying to propose efficient and selective drugs for the site of action, with best acceptance of patients, that can be metabolized to non-toxic derivatives. Prodrugs, soft drugs, codrugs are designed to maximize the amount of active drugs that reaches the site of action, through changing the physicochemical, biopharmaceutical or pharmacokinetic properties of the parent drugs. For last years different concepts of drug delivery have been developed to achieve the best patients ’ tolerance of a drug that has no undesirable properties. It is established that future studies will ameliorate drug properties so as to achieve the best drug delivery system.