Development and characterization of drug delivery systems for targeting mammalian cells and tissues: a review.

Recent advances in the development of diagnostics and therapeutics in the fields of recombinant biochemistry, solid phase peptide synthesis as well as in galenical research have resulted in highly specific and efficient components. Presently, millions of patients can profit from these new therapeutic modalities. The application of an effective anti-tumor dose of drugs can lead to marked toxicity in patients. Therefore, safe and efficient possibilities to transport these compounds to the target are of outmost importance. The importance of drug delivery is pivotal in the wide area of pharmacological research. However, until now, this issue is still to be solved. The main goal of every drug delivery system is the delivery of a precise amount of a drug at a pre-programmed rate to the desired location in order to achieve the necessary drug concentration in the targeted organ for effective treatment. The key problem still remains the achievement of curative doses in a pharmacologically active state in the desired target while avoiding side effects. Although respectable advances can be recognized in this field, the currently applied mechanisms for the transport of therapeutic molecules across biological membranes still remain far from being efficient. Helper molecules could improve delivery to desired target sites. Presently, a number of efforts are made and a huge spectrum of biochemical, biological, medical, pharmaceutical and physical possibilities are arising. However, the design and development of successful therapies based on this technology still remains a great challenge.