Drug targeting to the diseased liver

Many serious liver diseases affecting millions of people world-wide cannot be treated despite many efforts which warrants a search for new therapeutic strategies. Potent drugs may not be effective enough in vivo or exhibit adverse effects and enhanced delivery into the target cells may improve this significantly. We aim to summarize the available options for drug delivery to the different intrahepatic cell-types. The most relevant target cells are identified for each liver disease and the strategies for drug delivery to these cells are subsequently reviewed. The review describes the use of proteins, viruses, polymers and liposomes for therapeutic purposes in various liver diseases. It is shown that to date, all resident intrahepatic cells can be reached with several different drug carriers. Much progress has been made in recent years to deliver small drug molecules, proteins and nucleic acids specifically to the key pathogenic cells in vivo. The knowledge of drug targeting gained in the past decades, combined with a proper preclinical evaluation, may bring new therapeutics to the clinic in the near future.