Nanocarriers for cancer therapy

The requested features of pharmaceutical drug delivery (such as biodegradability or targeting) for intravenous administration are reasonably well met by liposomes, microcapsules, and nanoparticles for water-soluble drugs. The development of nanoparticulate drugs displaying all of these properties for poorly soluble pharmaceuticals still represents a challenge. Low solubility in water, however, tends to be an intrinsic property of many drugs, including some powerful anti-cancer agents. Intravenous administration of relatively large aggregates of an insoluble drug may result in embolisation of these particles into small blood capillaries and may cause unwanted effects like tissue ischemia. Hence, it does not allow for achieving therapeutically significant concentrations. Many promising drug candidates never enter further development processes because of solubility problems. On multiple occasions micelles can serve as drug delivery systems for poorly soluble pharmaceuticals. However, there are problems, which include low loading efficacy of the drug into the micelles; problems with controlling the release rate of the drug, and with micelle stability.