Liposomal pH-sensitive nanomedicines in preclinical development

MARIA JOSE MORILLA, EDER LILIA ROMERO

Bionanotechnology II; Global prospect

CRC Press, Taylor & Francis Group

Año: 2011; p. 383 - 414

In order to increase the therapeutic efficacy of a drug or to reduce its toxicity, biodistributionand intracellular traffic have to be changed, since the sole modification of itspharmacokinetics is insufficient. Nanomedicines (nano-objects loaded with small drugsor macromolecules) are powerful tools developed in the framework of the applicationof nanotechnology to medicine1 that, functioning as nano-drug delivery systems, arecapable of modifying the pathway followed by molecules. Pharmacokinetics, biodistribution,and intracellular traffic of loaded molecules no longer depend on their chemicalstructures but on the size, shape, and chemical structure of the nano-object. Liposomes,for instance, are the best known example of nano-objects, recently clasified as nanoparticules(with their three dimensions in the nanoscale (<200?300 nm)). Different fromconventional drug delivery systems, and depending on the biodegradability of the nanoobject,nanomedicines can cross anatomical and phenomenological barriers. They canbe administered by parenteral, transcutaneous, or mucosal vias, but changes in biodistributioncan only be achieved upon parenteral administration. An exclusive feature of nanomedicines is their uptake by phagocytic or pynocitic mechanisms upon cell recognition. The structure of the nanomedicine is responsible for its own recognitionby a given mechanism of cellular uptake. Each uptake mechanism leads towell-defined intracellular traffic mediated by vesicles, which ends up in different cellularcompartments.