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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.

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Hedgehog (Hh) signaling is an essential pathway in the human body, and plays a major role in embryo development and tissue patterning. Constitutive activation of the Hh signaling pathway through sporadic mutations or other mechanisms is explicitly associated with cancer development and progression in various solid malignancies. Therefore, targeted inhibition of the Hh signaling pathway has emerged as an attractive and validated therapeutic strategy for the treatment of a wide range of cancers. Vismodegib, a first-in-class Hh signaling pathway inhibitor was approved by the US Food and Drug Administration in 2012, and sonidegib, another potent Hh pathway inhibitor, received FDA's approval in 2015 as a new treatment of locally advanced or metastatic basal cell carcinoma. The clinical success of vismodegib and sonidegib provided strong support for the development of Hh signaling pathway inhibitors via targeting the smoothened (Smo) receptor. Moreover, Hh signaling pathway inhibitors aimed to target proteins, which are downstream or upstream of Smo, have also been pursued based on the identification of additional therapeutic benefits. Recently, much progress has been made in Hh singling and inhibitors of this pathway. Herein, medicinal chemistry strategies, especially the structural optimization process of different classes of Hh inhibitors, are comprehensively summarized. Further therapeutic potentials and challenges are also discussed.

Diabetes mellitus is a systemic disease responsible for morbidity in the western world and is gradually becoming prevalent in developing countries too. The prevalence of diabetes is rapidly increasing in industrialized countries and type 2 diabetes accounts for 90% of the disease. Insulin resistance is a major pathophysiological factor in the development of type 2 diabetes, occurring mainly in muscle, adipose tissues, and liver leading to reduced glucose uptake and utilization and increased glucose production. The prevalence and rising incidence of diabetes emphasized the need to explore new molecular targets and strategies to develop novel antihyperglycemic agents. Protein Tyrosine Phosphatase 1B (PTP 1B) has recently emerged as a promising molecular level legitimate therapeutic target in the effective management of type 2 diabetes. PTP 1B, a cytosolic nonreceptor PTPase, has been implicated as a negative regulator of insulin signal transduction. Therefore, PTP 1B inhibitors would increase insulin sensitivity by blocking the PTP 1B-mediated negative insulin signaling pathway and might be an attractive target for type 2 diabetes mellitus and obesity. With X-ray crystallography and NMR-based fragment screening, the binding interactions of several classes of inhibitors have been elucidated, which could help the design of future PTP 1B inhibitors. The drug discovery research in PTP 1B is a challenging area to work with and many pharmaceutical organizations and academic research laboratories are focusing their research toward the development of potential PTP 1B inhibitors which would prove to be a milestone for the management of diabetes.