Description: Purpose Trastuzumab combined with Doxorubicin (DOX) demonstrates significant clinical activity in human epidermal growth factor receptor-2 (HER2)-positive breast cancer (BC). However, emergence of treatment resistance and trastuzumab associated cardiotoxicity remain clinical challenges. In an effort to improve patient outcome, we have developed and evaluated novel tri-functional immunoliposomes (TFIL) that target HER2-receptors on BC cells and CD3-receptors on T-lymphocytes, and deliver DOX. Methods Trastuzumab (anti-HER2) and OKT-3 (anti-CD3) antibodies were conjugated to liposomes using a micelle-transfer method. Cytotoxicity of targeted immunoliposomes loaded with DOX was examined in vitro on HER2-positive BC cells (BT474), with peripheral blood monocytic cells (PBMC) as immune effector cells. Results TFIL demonstrated high antibody-liposome conjugation ratios (100–130 μg protein/μmol phospholipid) and cargo capacity (0.21 mol:mol drug:lipid), highly efficient DOX loading (〉90%), a particle size favorable for extended circulation (~150 nm), and good stability (up to 3 months at 4°C). In the presence of PBMCs, TFIL showed complete killing of BT474 cells, and were superior to mono-targeted trastuzumab-bearing liposomes, non-targeted liposomes, and free Trastuzumab and DOX. Conclusions Novel anti-HER2xCD3 + DOX TFIL show promise as a means to both engage immune cells against HER2 positive breast cancer cells and deliver chemotherapy, and have the potential to improve clinical outcomes.

Description: Purpose The objective was the development of a whole-body physiologically-based pharmacokinetic (WB-PBPK) model for colistin, and its prodrug colistimethate sodium (CMS), in pigs to explore their tissue distribution, especially in kidneys. Methods Plasma and tissue concentrations of CMS and colistin were measured after systemic administrations of different dosing regimens of CMS in pigs. The WB-PBPK model was developed based on these data according to a non-linear mixed effect approach and using NONMEM software. A detailed sub-model was implemented for kidneys to handle the complex disposition of CMS and colistin within this organ. Results The WB-PBPK model well captured the kinetic profiles of CMS and colistin in plasma. In kidneys, an accumulation and slow elimination of colistin were observed and well described by the model. Kidneys seemed to have a major role in the elimination processes, through tubular secretion of CMS and intracellular degradation of colistin. Lastly, to illustrate the usefulness of the PBPK model, an estimation of the withdrawal periods after veterinary use of CMS in pigs was made. Conclusions The WB-PBPK model gives an insight into the renal distribution and elimination of CMS and colistin in pigs; it may be further developed to explore the colistin induced-nephrotoxicity in humans.

Description: Purpose Acute lung injury (ALI) is a fatal syndrome in critically ill patients. It is characterized by lung edema and inflammation. Numerous pro-inflammatory mediators are released into alveoli. Among them, interleukin-1beta (IL-1β) causes an increase in solute permeability across the alveolar-capillary barrier leading to edema. It activates key effector cells (alveolar epithelial and endothelial cells) releasing inflammatory chemokines and cytokines. The purpose of the study was to demonstrate that nebulized liposomes inhibit ALI in vivo . Methods In vivo ALI model was simulated through intra-tracheal instillation of IL-1β solution (100 μg/mL in PBS, pH 7.2, 200 μL) in male Sprague-Dawley rats. Various formulations were tested in ALI induced rats. These formulations include plain liposomes (PL), methylprednisolone sodium succinate solution (MPS solution), cRGD-peptide grafted liposomes (L cRGD ) and methylprednisolone sodium succinate encapsulated and cRGD-peptide grafted liposomes (MPS-L cRGD ). Formulations were nebulized in vivo in rats using micro-pump nebulizer. Results Liposome formulations exhibited higher levels of drug concentration in lungs. The physicochemical parameters demonstrated that the liposome formulations were stable. On the basis of aerodynamic droplet-size, nebulized formulations were estimated to deposit in different regions of respiratory tract, especially alveolar region, Among the formulations, MPS-L cRGD caused significant reduction of edema, neutrophil infiltration and inflammation biochemical marker levels. Conclusion From the results, it can be inferred that nebulization of targeted liposomes had facilitated spatial and temporal modulation of drug delivery resulting in alleviation of ALI.

Description: Purpose Lung cancer is the leading cause of cancer-related deaths. The aim of this study was to design solid lipid core nanocapsules (SLCN) comprising a solid lipid core and a PEGylated polymeric corona for paclitaxel (PTX) and erlotinib (ERL) co-delivery to non-small cell lung cancer (NSCLC), and evaluate their physicochemical characteristics and in vitro activity in NCI-H23 cells. Methods PTX/ERL-SLCN were prepared by nanoprecipitation and sonication and physicochemically characterized by dynamic light scattering, transmission electron microscopy, differential scanning calorimetry, X-ray diffraction, and Fourier-transform infrared spectroscopy. In vitro release profiles at pH 7.4 and pH 5.0 were studied and analyzed. In vitro cytotoxicity and cellular uptake and apoptosis assays were performed in NCI-H23 cells. Results PTX/ERL-SLCN exhibited appropriately-sized spherical particles with a high payload. Both PTX and ERL showed pH-dependent and sustained release in vitro profiles. PTX/ERL-SLCN demonstrated concentration- and time-dependent uptake by NCI-H23 cells and caused dose-dependent cytotoxicity in the cells, which was remarkably greater than that of not only the free individual drugs but also the free drug cocktail. Moreover, well-defined early and late apoptosis were observed with clearly visible signs of apoptotic nuclei. Conclusion PTX/ERL-SLCN could be employed as an optimal approach for combination chemotherapy of NSCLC.

Description: Purpose To investigate the blood-to-retina verapamil transport at the blood-retinal barrier (BRB). Methods EverFluor FL Verapamil (EFV) was adopted as the fluorescent probe of verapamil, and its transport across the BRB was investigated with common carotid artery infusion in rats. EFV transport at the inner and outer BRB was investigated with TR-iBRB2 cells and RPE-J cells, respectively. Results The signal of EFV was detected in the retinal tissue during the weak signal of cell impermeable compound. In TR-iBRB2 cells, the localization of EFV differed from that of LysoTracker ® Red, a lysosomotropic agent, and was not altered by acute treatment with NH 4 Cl. In RPE-J cells, the punctate distribution of EFV was partially observed, and this was reduced by acute treatment with NH 4 Cl. EFV uptake by TR-iBRB2 cells was temperature-dependent and membrane potential- and pH-independent, and was significantly reduced by NH 4 Cl treatment during no significant effect obtained by different extracellular pH and V-ATPase inhibitor. The EFV uptake by TR-iBRB2 cells was inhibited by cationic drugs, and inhibited by verapamil in a concentration-dependent manner with an IC 50 of 98.0 μM. Conclusions Our findings provide visual evidence to support the significance of carrier-mediated transport in the blood-to-retina verapamil transport at the BRB.

Description: Purpose The main purpose of this study was to formulate an oil-in-water nanoemulsion of a next generation taxoid DHA-SBT-1214 and evaluate its biodistribution and pharmacokinetics. Methods DHA-SBT-1214 was encapsulated in a fish oil containing nanoemulsion using a high pressure homogenization method. Following morphological characterization of the nanoemulsions, qualitative and quantitative biodistribution was evaluated in naïve and cancer stem cell-enriched PPT-2 human prostate tumor bearing mice. Results DHA-SBT-1214 was successfully encapsulated up to 20 mg/ml in the nanoemulsion formulation and had an average oil droplet size of 200 nm. Using a DiR near infra-red dye encapsulated nanoemulsion, we have shown the delivery of nanoemulsion to mouse tumor region. By quantitative analysis, DHA-SBT-1214 encapsulated nanoemulsion demonstrated improved pharmacokinetic properties in plasma and different tissues as compared to its solution form. Furthermore, the nanoemulsions were stable and had slower in vitro drug release compared to its solution form. Conclusions The results from this study demonstrated effective encapsulation of the drug in a nanoemulsion and this nanoemulsion showed sustained plasma levels and enhanced tumor delivery relative to the solution form.

Description: Purpose Polymeric drugs, including patiromer (Veltassa®), bind target molecules or ions in the gut, allowing fecal elimination. Non-absorbed insoluble polymers, like patiromer, avoid common systemic drug-drug interactions (DDIs). However, the potential for DDI via polymer binding to orally administered drugs during transit of the gastrointestinal tract remains. Here we elucidate the properties correlated with drug-patiromer binding using quantitative structure-property relationship (QSPR) models. Methods We selected 28 drugs to evaluate for binding to patiromer in vitro over a range of pH and ionic conditions intended to mimic the gut environment. Using this in vitro data, we developed QSPR models using step-wise linear regression and analyzed over 100 physiochemical drug descriptors. Results Four descriptors emerged that account for ~70% of patiromer-drug binding in vitro : the computed surface area of hydrogen bond accepting atoms, ionization potential, electron affinity, and lipophilicity ( R 2  = 0.7, Q 2  = 0.6). Further, certain molecular properties are shared by nonbinding, weak, or strong binding compounds. Conclusions These findings offer insight into drivers of in vitro binding to patiromer and describe a useful approach for assessing potential drug-binding risk of investigational polymeric drugs.

Description: Purpose This work explores synthesis of novel cholesterol derivative for the preparation of cationic liposomes and its interaction with Paclitaxel (PTX) within liposome membrane using molecular dynamic (MD) simulation and in-vitro studies. Methods Cholesteryl Arginine Ethylester (CAE) was synthesized and characterized. Cationic liposomes were prepared using Soy PC (SPC) at a molar ratio of 77.5:15:7.5 of SPC/CAE/PTX. Conventional liposomes were composed of SPC/cholesterol/PTX (92:5:3 M ratio). The interaction between paclitaxel, ligand and the membrane was studied using 10 ns MD simulation. The interactions were studied using Differential Scanning Calorimetry (DSC) and Small Angle Neutron Scattering analysis. The efficacy of liposomes was evaluated by MTT assay and endothelial cell migration assay on different cell lines. The safety of the ligand was determined using the Comet Assay. Results The cationic liposomes improved loading efficiency and stability compared to conventional liposomes. The increased PTX loading could be attributed to the hydrogen bond between CAE and PTX and deeper penetration of PTX in the bilayer. The DSC study suggested that inclusion of CAE in the DPPC bilayer eliminates T g . SANS data showed that CAE has more pronounced membrane thickening effect as compared to cholesterol. The cationic liposomes showed slightly improved cytotoxicity in three different cell lines and improved endothelial cell migration inhibition compared to conventional liposomes. Furthermore, the COMET assay showed that CAE alone does not show any genotoxicity. Conclusions The novel cationic ligand (CAE) retains paclitaxel within the phospholipid bilayer and helps in improved drug loading and physical stability. Graphical Abstract ᅟ

Description: Purpose The aim of this study was to determine the potential of magnetic resonance imaging to evaluate the biodistribution of exogenous iron within 24 h after one single injection of Venofer® (iron sucrose). Methods Venofer® was evaluated in vitro for its ability to generate contrast in MR images. Subsequently, iron disposition was assessed in rats with MRI, in vivo up to 3 h and post mortem at 24 h after injection of Venofer®, at doses of 10- and 40 mg/kg body weight ( n  = 2 × 4), or saline ( n  = 4). Results Within 10–20 min after injection of Venofer®, transverse relaxation rates (R 2 ) clearly increased, representative of a local increase in iron concentration, in liver, spleen and kidney, including the kidney medulla and cortex. In liver and spleen R 2 values remained elevated up to 3 h post injection, while the initial R 2 increase in the kidney was followed by gradual decrease towards baseline levels. Bone marrow and muscle tissue did not show significant increases in R 2 values. Whole-body post mortem MRI showed most prominent iron accumulation in the liver and spleen at 24 h post injection, which corroborated the in vivo results. Conclusions MR imaging is a powerful imaging modality for non-invasive assessment of iron distribution in organs. It is recommended to use this whole-body imaging approach complementary to other techniques that allow quantification of iron disposition at a (sub)cellular level.

Description: Purpose Volume of distribution at steady state (Vd ss ) is a fundamental pharmacokinetic (PK) parameter driven predominantly by passive processes and physicochemical properties of the compound. Human Vd ss can be estimated using in silico mechanistic methods or empirically scaled from Vd ss values obtained from preclinical species. In this study the accuracy and the complementarity of these two approaches are analyzed leveraging a large data set (over 150 marketed drugs). Methods For all the drugs analyzed in this study experimental in vitro measurements of LogP, plasma protein binding and pKa are used as input for the mechanistic in silico model to predict human Vd ss . The software used for predicting human tissue partition coefficients and Vd ss based on the method described by Rodgers and Rowland is made available as supporting information. Results This assessment indicates that overall the in silico mechanistic model presented by Rodgers and Rowland is comparably accurate or superior to empirical approaches based on the extrapolation of in vivo data from preclinical species. Conclusions These results illustrate the great potential of mechanistic in silico models to accurately predict Vd ss in humans. This in silico method does not rely on in vivo data and is, consequently, significantly time and resource sparing. The success of this in silico model further suggests that reasonable predictability of Vd ss in preclinical species could be obtained by a similar process.