In vitro and in vivo characterization of pharmaceutical nanocarriers used for drug delivery.

Nanotechnology has emerged strongly in most of the field of sciences at a tiny scale. At this size, atoms and molecules work differently and present a diversity of amazing and appealing applications. Pharmaceutical nanocarriers comprise nanoparticles, nanospheres, nanocapsules, nanoemulsion, nanoliposomes and nanoniosomes. The major objectives in designing nanocarriers are to manage particle size, surface properties as well as drug release in order to fulfil specific objectives. Hence, characterizations of nanocarriers are very critical to control their desired in vitro and in vivo behaviour. Nanocarriers are characterized by their size, morphology and surface charge, using highly advanced microscopic techniques as scanning electron microscopy, transmission electron microscopy and atomic force microscopy. Surface morphology and size are measured by electron microscopy while dynamic light scattering and photon-correlation spectroscopy are used to determine the particle size and size distribution. Colloidal stability is ascertained through zeta potential which is an indirect measure of the surface charge and differential scanning calorimetry is used to characterize particles and drug interaction. Further, binding and internalization of targeted carriers to the specific cells could be determined by cell uptake study. Biodistribution study of targeted nanocarriers is carried out and intracellular uptake and subcellular localization of the nanocarrier could be confirmed using confocal microscopy. This review covers all the aforementioned aspect related to in vitro and in vivo characterization of pharmaceutical nanocarriers.