Pharmaceutical Research (v.35, #4)

Barriers to Drug Distribution into the Perinatal and Postnatal Brain by Jean-François Ghersi-Egea; Elodie Saudrais; Nathalie Strazielle (1-10).
Drug bioavailability to the developing brain is a major concern in the treatment of neonates and infants as well as pregnant and breast-feeding women. Central adverse drug reactions can have dramatic consequences for brain development, leading to major neurological impairment. Factors setting the cerebral bioavailability of drugs include protein-unbound drug concentration in plasma, local cerebral blood flow, permeability across blood-brain interfaces, binding to neural cells, volume of cerebral fluid compartments, and cerebrospinal fluid secretion rate. Most of these factors change during development, which will affect cerebral drug concentrations. Regarding the impact of blood-brain interfaces, the blood-brain barrier located at the cerebral endothelium and the blood-cerebrospinal fluid barrier located at the choroid plexus epithelium both display a tight phenotype early on in embryos. However, the developmental regulation of some multispecific efflux transporters that also limit the entry of numerous drugs into the brain through barrier cells is expected to favor drug penetration in the neonatal brain. Finally, drug cerebral bioavailability is likely to be affected following perinatal injuries that alter blood-brain interface properties. A thorough investigation of these mechanisms is mandatory for a better risk assessment of drug treatments in pregnant or breast-feeding women, and in neonate and pediatric patients.
Keywords: blood-brain barrier; cerebrospinal fluid; choroid plexus; development; efflux transporters

Anti-GD2 Immunoliposomes for Targeted Delivery of the Survivin Inhibitor Sepantronium Bromide (YM155) to Neuroblastoma Tumor Cells by Shima Gholizadeh; Emmy M. Dolman; Rebecca Wieriks; Rolf W. Sparidans; Wim E. Hennink; Robbert J. Kok (1-15).
Sepantronium bromide (YM155) is a hydrophilic quaternary compound that cannot be administered orally due to its low oral bioavailability; it is furthermore rapidly eliminated via the kidneys. The current study aims at improving the pharmacokinetic profile of YM155 by its formulation in immunoliposomes that can achieve its enhanced delivery into tumor tissue and facilitate uptake in neuroblastoma cancer cells.PEGylated YM155 loaded liposomes composed of DPPC, cholesterol and DSPE-PEG2000 were prepared via passive film-hydration and extrusion method. Targeted (i.e. immuno-)liposomes were prepared by surface functionalization with SATA modified monoclonal anti-disialoganglioside (GD2) antibodies. Liposomes were characterized based on their size, charge, antibody coupling and YM155 encapsulation efficiency, and stability. Flow cytometry analysis and confocal microscopy were performed on IMR32 and KCNR neuroblastoma cell lines. The efficacy of developed formulations were assessed by in-vitro toxicity assays. A pilot pharmacokinetic analysis was performed to assess plasma circulation and tumor accumulation profiles of the developed liposomal formulations.YM155 loaded immunoliposomes had a size of 170 nm and zeta potential of −10 mV, with an antibody coupling efficiency of 60% andYM155 encapsulation efficiency of14%. Targeted and control liposomal formulations were found to have similar YM155 release rates in a release medium containing 50% serum. An in-vitro toxicity study on KCNR cells showed less toxicity for immunoliposomes as compared to free YM155. In-vivo pharmacokinetic evaluation of YM155 liposomes showed prolonged blood circulation and significantly increased half-lives of liposomal YM155 in tumor tissue, as compared to a bolus injection of free YM155.YM155 loaded immunoliposomes were successfully formulated and characterized, and initial in-vivo results show their potential for improving the circulation time and tumor accumulation of YM155.
Keywords: immunoliposomes; neuroblastoma cells; sepantronium bromide (YM155); targeted delivery

Comparison of Gene Transfection and Cytotoxicity Mechanisms of Linear Poly(amidoamine) and Branched Poly(ethyleneimine) Polyplexes by Ammar A. Y. Almulathanon; Elisabetta Ranucci; Paolo Ferruti; Martin C. Garnett; Cynthia Bosquillon (1-12).
This study aimed to further explore the mechanisms behind the ability of certain linear polyamidoamines (PAAs) to transfect cells with minimal cytotoxicity.The transfection efficiency of DNA complexed with a PAA of a molecular weight over 10 kDa or 25 kDa branched polyethyleneimine (BPEI) was compared in A549 cells using a luciferase reporter gene assay. The impact of endo/lysosomal escape on transgene expression was investigated by transfecting cells in presence of bafilomycin A1 or chloroquine. Cytotoxicity caused by the vectors was evaluated by measuring cell metabolic activity, lactate dehydrogenase release, formation of reactive oxygen species and changes in mitochondrial membrane potential.The luciferase activity was ~3-fold lower after transfection with PAA polyplexes than with BPEI complexes at the optimal polymer to nucleotide ratio (RU:Nt). However, in contrast to BPEI vectors, PAA polyplexes caused negligible cytotoxic effects. The transfection efficiency of PAA polyplexes was significantly reduced in presence of bafilomycin A1 while chloroquine enhanced or decreased transgene expression depending on the RU:Nt.PAA polyplexes displayed a pH-dependent endo/lysosomal escape which was not associated with cytotoxic events, unlike observed with BPEI polyplexes. This is likely due to their greater interactions with biological membranes at acidic than neutral pH.
Keywords: cationic polymers; cytotoxicity; DNA-complexes; gene delivery; linear polyamidoamines

Ionophore and Biometal Modulation of P-glycoprotein Expression and Function in Human Brain Microvascular Endothelial Cells by Mitchell P. McInerney; Irene Volitakis; Ashley I. Bush; William A. Banks; Jennifer L. Short; Joseph A. Nicolazzo (1-12).
Biometals such as zinc and copper have been shown to affect tight junction expression and subsequently blood-brain barrier (BBB) integrity. Whether these biometals also influence the expression and function of BBB transporters such as P-glycoprotein (P-gp) however is currently unknown.Using the immortalised human cerebral microvascular endothelial (hCMEC/D3) cell line, an in-cell western assay (alongside western blotting) assessed relative P-gp expression after treatment with the metal ionophore clioquinol and biometals zinc and copper. The fluorescent P-gp substrate rhodamine-123 was employed to observe functional modulation, and inductively coupled plasma mass spectrometry (ICP-MS) provided information on biometal trafficking.A 24-h treatment with clioquinol, zinc and copper (0.5, 0.5 and 0.1 μM) induced a significant upregulation of P-gp (1.7-fold) assessed by in-cell western and this was confirmed with western blotting (1.8-fold increase). This same treatment resulted in a 23% decrease in rhodamine-123 accumulation over a 1 h incubation. ICP-MS demonstrated that while t8his combination treatment had no effect on intracellular zinc concentrations, the treatment significantly enhanced bioavailable copper (4.6-fold).Enhanced delivery of copper to human brain microvascular endothelial cells is associated with enhanced expression and function of the important efflux pump P-gp, which may provide therapeutic opportunities for P-gp modulation.
Keywords: blood-brain barrier; clioquinol; ionophore; P-glycoprotein; transporter

The Use of Magnetic Resonance Imaging for Non-Invasive Assessment of Venofer® Biodistribution in Rats by Kimberley Span; Ebel H. E. Pieters; Wim E. Hennink; Annette van der Toorn; Vera Brinks; Rick M. Dijkhuizen; Geralda A. F. van Tilborg (1-12).
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).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).Within 10–20 min after injection of Venofer®, transverse relaxation rates (R2) 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 R2 values remained elevated up to 3 h post injection, while the initial R2 increase in the kidney was followed by gradual decrease towards baseline levels. Bone marrow and muscle tissue did not show significant increases in R2 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.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.
Keywords: biodistribution; intravenous; iron; MRI; oxidative stress

Biodistribution and Pharmacokinetic Evaluations of a Novel Taxoid DHA-SBT-1214 in an Oil-in-Water Nanoemulsion Formulation in Naïve and Tumor-Bearing Mice by Gulzar Ahmad; Florence Gattacecca; Rana El Sadda; Galina Botchkina; Iwao Ojima; James Egan; Mansoor Amiji (1-13).
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.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.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.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.
Keywords: biodistribution and pharmacokinetic; nanoemulsion formulation; prostate tumor; taxoid

Rational Design of Cholesterol Derivative for Improved Stability of Paclitaxel Cationic Liposomes by Jasmin Monpara; Chryso Kanthou; Gillian M. Tozer; Pradeep R. Vavia (1-17).
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.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.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 Tg. 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.The novel cationic ligand (CAE) retains paclitaxel within the phospholipid bilayer and helps in improved drug loading and physical stability. Graphical Abstractᅟ
Keywords: COMET assay; molecular dynamic simulation; paclitaxel-loaded cationic liposomes; trans-well migration assay

Comparing Mechanistic and Preclinical Predictions of Volume of Distribution on a Large Set of Drugs by Rosa Chan; Tom De Bruyn; Matthew Wright; Fabio Broccatelli (1-11).
Volume of distribution at steady state (Vdss) is a fundamental pharmacokinetic (PK) parameter driven predominantly by passive processes and physicochemical properties of the compound. Human Vdss can be estimated using in silico mechanistic methods or empirically scaled from Vdss 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).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 Vdss. The software used for predicting human tissue partition coefficients and Vdss based on the method described by Rodgers and Rowland is made available as supporting information.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.These results illustrate the great potential of mechanistic in silico models to accurately predict Vdss 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 Vdss in preclinical species could be obtained by a similar process.
Keywords: mechanistic in silico model; PBPK; physicochemical properties; preclinical; volume of distribution (Vdss)

Use of QSPR Modeling to Characterize In Vitro Binding of Drugs to a Gut-Restricted Polymer by Christine Taylor Brew; James F. Blake; Anita Mistry; Fengling Liu; Diana Carreno; Deidre Madsen; YongQi Mu; Martha Mayo; Wilhelm Stahl; David Matthews; Derek Maclean; Steve Harrison (1-10).
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.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.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.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.
Keywords: drug interaction; electron affinity; hydrogen bonding; ionization potential; lipophilicity

The purpose was to evaluate DSF for high throughput screening of protein thermal stability (unfolding/ aggregation) across a wide range of formulations. Particular focus was exploring PROTEOSTAT® – a commercially available fluorescent rotor dye – for detection of aggregation in surfactant containing formulations. Commonly used hydrophobic dyes (e.g. SYPRO™ Orange) interact with surfactants, complicating DSF measurements.CRM197 formulations were prepared and analyzed in standard 96-well plate rT-PCR system, using SYPRO™ Orange and PROTEOSTAT® dyes. Orthogonal techniques (DLS and IPF) are employed to confirm unfolding/aggregation in selected formulations. Selected formulations are subjected to non-thermal stresses (stirring and shaking) in plate based format to characterize aggregation with PROTEOSTAT®.Agreement is observed between SYPRO™ Orange (unfolding) and PROTEOSTAT® (aggregation) DSF melt temperatures across wide range of non-surfactant formulations. PROTEOSTAT® can clearly detect temperature induced aggregation in low concentration (0.2 mg/mL) CRM197 formulations containing surfactant. PROTEOSTAT® can be used to explore aggregation due to non-thermal stresses in plate based format amenable to high throughput screening.DSF measurements with complementary extrinsic dyes (PROTEOSTAT®, SYPRO™ Orange) are suitable for high throughput screening of antigen thermal stability, across a wide range of relevant formulation conditions – including surfactants –with standard, plate based rT-PCR instrumentation.
Keywords: aggregation; fluorescence spectroscopy; high-throughput screening; modified diphtheria toxin (CRM197); vaccine formulation

Double or Simple Emulsion Process to Encapsulate Hydrophilic Oxytocin Peptide in PLA-PEG Nanoparticles by Betty Gourdon; Xavier Declèves; Jean-Manuel Péan; Caroline Chemin (1-18).
Oral drug delivery using NPs is a current strategy for poorly absorbed molecules. It offers significant improvement in terms of bioavailability. However, the encapsulation of proteins and peptides in polymeric NPs is a challenge. Firstly, the present study focused on the double emulsion process in order to encapsulate the OXY peptide. Then the technique was challenged by a one-step simplified process, the simple emulsion.In order to study the influence of formulation and process parameters, factorial experimental designs were carried on. The responses observed were the NP size (<200 nm in order to penetrate the intestinal mucus layer), the suspension stability (ZP < |30| mV) and the OXY loading.It was thus found that the amount and the nature of surfactant, the ratio between the phases, the amount of PLA-PEG polymer and OXY, the presence of a viscosifying agent, and the duration of the sonication could significantly influence the responses. Finally, OXY-loaded NPs from both processes were obtained with NP size of 195 and 226 nm and OXY loading of 4 and 3.3% for double and simple emulsions, respectively.The two processes appeared to be suitable for OXY encapsulation and comparable in term of NP size, peptide drug load and release obtained.
Keywords: emulsion process; factorial experimental design; oxytocin peptide; polymer nanoparticles

In Vitro’, ‘In Vivo’ and ‘In Silico’ Investigation of the Anticancer Effectiveness of Oxygen-Loaded Chitosan-Shelled Nanodroplets as Potential Drug Vector by Amina Khadjavi; Ilaria Stura; Mauro Prato; Valerio Giacomo Minero; Alice Panariti; Ilaria Rivolta; Giulia Rossana Gulino; Federica Bessone; Giuliana Giribaldi; Elena Quaglino; Roberta Cavalli; Federica Cavallo; Caterina Guiot (1-11).
Chitosan-shelled/decafluoropentane-cored oxygen-loaded nanodroplets (OLN) are a new class of nanodevices to effectively deliver anti-cancer drugs to tumoral cells. This study investigated their antitumoral effects ‘per se’, using a mathematical model validated on experimental data. OLN were prepared and characterized either in vitro or in vivo. TUBO cells, established from a lobular carcinoma of a BALB-neuT mouse, were investigated following 48 h of incubation in the absence/presence of different concentrations of OLN. OLN internalization, cell viability, necrosis, apoptosis, cell cycle and reactive oxygen species (ROS) production were checked as described in the Method section. In vivo tumor growth was evaluated after subcutaneous transplant in BALB/c mice of TUBO cells either without treatment or after 24 h incubation with 10% v/v OLN.OLN showed sizes of about 350 nm and a positive surface charge (45 mV). Dose-dependent TUBO cell death through ROS-triggered apoptosis following OLN internalization was detected. A mathematical model predicting the effects of OLN uptake was validated on both in vitro and in vivo results.Due to their intrinsic toxicity OLN might be considered an adjuvant tool suitable to deliver their therapeutic cargo intracellularly and may be proposed as promising combined delivery system.
Keywords: antitumor nanodevice; breast cancer; chitosan nanodroplet; nanocarrier; oxygen

To identify conditions allowing the use of cell-based models for studies of drug absorption during in vitro lipolysis of lipid-based formulations (LBFs).Caco-2 was selected as the cell-based model system. Monolayer integrity was evaluated by measuring mannitol permeability after incubating Caco-2 cells in the presence of components available during lipolysis. Pure excipients and formulations representing the lipid formulation classification system (LFCS) were evaluated before and after digestion. Porcine mucin was evaluated for its capacity to protect the cell monolayer.Most undigested formulations were compatible with the cells (II-LC, IIIB-LC, and IV) although some needed mucin to protect against damaging effects (II-MC, IIIB-MC, I-LC, and IIIA-LC). The pancreatic extract commonly used in digestion studies was incompatible with the cells but the Caco-2 monolayers could withstand immobilized recombinant lipase. Upon digestion, long chain formulations caused more damage to Caco-2 cells than their undigested counterparts whereas medium chain formulations showed better tolerability after digestion.Most LBFs and components thereof (undigested and digested) are compatible with Caco-2 cells. Pancreatic enzyme is not tolerated by the cells but immobilized lipase can be used in combination with the cell monolayer. Mucin is beneficial for critical formulations and digestion products.
Keywords: Caco-2 cells; digestion; intestinal absorption; lipid-based formulation

Human Primary Cell-Based Organotypic Microtissues for Modeling Small Intestinal Drug Absorption by Seyoum Ayehunie; Tim Landry; Zachary Stevens; Alex Armento; Patrick Hayden; Mitchell Klausner (1-18).
The study evaluates the use of new in vitro primary human cell-based organotypic small intestinal (SMI) microtissues for predicting intestinal drug absorption and drug-drug interaction.The SMI microtissues were reconstructed using human intestinal fibroblasts and enterocytes cultured on a permeable support. To evaluate the suitability of the intestinal microtissues to model drug absorption, the permeability coefficients across the microtissues were determined for a panel of 11 benchmark drugs with known human absorption and Caco-2 permeability data. Drug-drug interactions were examined using efflux transporter substrates and inhibitors.The 3D–intestinal microtissues recapitulate the structural features and physiological barrier properties of the human small intestine. The microtissues also expressed drug transporters and metabolizing enzymes found on the intestinal wall. Functionally, the SMI microtissues were able to discriminate between low and high permeability drugs and correlated better with human absorption data (r2 = 0.91) compared to Caco-2 cells (r2 = 0.71). Finally, the functionality of efflux transporters was confirmed using efflux substrates and inhibitors which resulted in efflux ratios of >2.0 fold and by a decrease in efflux ratios following the addition of inhibitors.The SMI microtissues appear to be a useful pre-clinical tool for predicting drug bioavailability of orally administered drugs.
Keywords: caco-2; drug-drug interaction; drug metabolizing enzymes; drug permeation; drug transporters; organotypic small intestinal microtissues

Hyaluronidase Enzyme-responsive Targeted Nanoparticles for Effective Delivery of 5-Fluorouracil in Colon Cancer by Haiping Jiang; Xinyan Shi; Xiaoyun Yu; Xinjia He; Yongheng An; Haijun Lu (1-9).
In this study, we have successfully prepared the hyaluronic acid (HA)-conjugated mesoporous silica nanoparticles loaded with 5-fluorouracil (5-FU) to increase the anticancer efficacy in colon cancers.The particles were nanosized and perfectly spherical. In vitro release kinetics clearly showed the enzyme-sensitive release of 5-FU from HA-conjugated 5-FU loaded mesoporous silica nanoparticles (HA/FMSN).The presence of HA on the surface of nanoparticles targeted the CD44 receptors overexpressed in the colon cancer cells In vitro cell viability and apoptosis assay clearly showed the superior anticancer effect of HA/FMSN in HT29 colon cancer cells. HA/FMSN exhibited a remarkably higher 43% of cells in early apoptosis phase and 55% of cells in late apoptosis phase indicating the superior anticancer effect of HA/FMSN. HA/FMSN exhibited a significant reduction in the tumor burden compared to that of any group. HA/FMSN was 3-fold more effective than free drug and 2-fold more effective than -FU loaded mesoporous silica nanoparticles (FMSN).Overall, results suggest that the novel delivery strategy could hold enormous potential in colon cancer targeting.
Keywords: 5-fluorouracil; Apoptosis; Colon cancers; Hyaluronic acid; Mesoporous silica nanoparticles

Breast cancer is the second most common cause of mortality in women in the United States. Targeted delivery of antitumor breast cancer drugs as a drug-delivery strategy may allow direct delivery into the tumor. Currently, chemotherapy is one of the principle strategies for cancer treatment, but it can have toxic side effects. Nanotechnology attempts to resolve these challenges by loading drugs in nanoparticles, such as solid lipid nanoparticles (SLN). In response to the breast cancer drug 5-fluorouracil (5-FU), p38MAPK signaling has been investigated since the 1990s. Ribavirin, a nucleotide derivative, inhibits p38MAPK in infected hepatocytes. A ribavirin prodrug, taribavirin (TBV), was recently synthesized to concentrate in the liver and have minimal concentration in red blood cells.In this study, TBV and 5-FU-pegylated SLNs were prepared and characterized. The in vitro cytotoxicity was evaluated against MCF-7 breast cancer cells. Using molecular docking experiments, 5-FU and TBV were docked on p38MAPK protein.The TBV nanoformulation had the highest cytotoxic effects, achieving IC50 = 0.690 μM after 24 h, compared with free TBV, which also achieved a good cytotoxic effect (IC50 = 0.756 μM). However, there was a detectable cytotoxic effect and an undetectable IC50 of 5-FU nanoparticles and free 5-FU on MCF-7 cells.The effect of TBV nanoparticles on MCF-7 cells may be due to its inhibitory effect against p38MAPK protein, where it fits inside the active pocket site of the p38 protein molecular surface, with a minimum binding affinity of −5.5 kcal/mol (rmsd of 1.07), and it formed strong hydrogen bonds with amino acids ASP’168, ILE’166, HIS’148, and ILE’147. Further studies are warranted to investigate the mechanistic details of the proposed approach.
Keywords: 5-fluorouracil; breast cancer; solid lipid nanoparticles; taribavirin

A multidrug resistance (MDR) modulator, disulfiram (DSF), was incorporated into pure paclitaxel (PTX) nanoparticles to construct a smart paclitaxel-disulfiram nanococrystals (PTX-DSF Ns) stabilized by β-lactoglobulin (β-LG), with the aim to reverse MDR and therefore enhnce cytotoxicity towards Taxol-resistant A549 cells (A549/TAX).PTX-DSF Ns was prepared by antisolvent precipitation method. Flow cytometry was used to determine the cell uptake, drug efflux inhibition, cell cycle phase arrest and apoptosis. MDR-1 gene expression level was detected by real time quantitative PCR and gel electrophoresis.PTX-DSF Ns prepared from the optimized formulation had an optimum diameter of 160 nm, was stable and had a high drug-loading capacity. Importantly, the uptake of PTX-DSF Ns in A549/TAX cells was 14-fold greater than the uptake of PTX Ns. Furthermore, PTX-DSF Ns promoted 5-folds increase in apoptosis, enabled 7-folds reduction in the IC50, and rendered 8.9-fold decrease in the dose compared with free PTX.PTX-DSF Ns with a precise mass ratio offer efficient cytotoxicity against Taxol-resistant cells and a novel approach for codelivery and sensitizing MDR cancer to chemotherapy. In addition, the use of nanosuspensions as a combined treatment provides a new research avenue for nanosuspensions.
Keywords: apoptosis; combined therapy; multidrug resistance; nanosuspensions; p-glycoprotein

CpG-PEG Conjugates and their Immune Modulating Effects after Systemic Administration by Caixing Wu; Xiaofei Xiang; Yang Yue; Lin Li; Yesen Li; Chong Zhang; Yuhong Xu (1-11).
Synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG motifs were found to be able to target cells that express Toll-like receptor 9 to modulate innate and adaptive immune reactions. But their in vivo application in immunotherapy against cancer has not been successful. We attempted in this study to examine polyethylene-glycol (PEG) conjugated CpG ODNs and investigated their mechanism of immune modulation in anti-cancer therapy.CpG-PEG conjugates with different PEG lengths were synthesized. In vitro activity as well as in vivo pharmacokinetics and pharmacodynamics properties were evaluated.CpG-PEG20Ks were found to be able to persist longer in circulation and activate various downstream effector cells. After intravenous injection, they resulted in higher levels of IL-12p70 in the circulation and lower M-MDSC infiltrates in the tumor microenvironment. Such activities were different from those of CpG ODNs without PEGylation, suggesting different PK-PD profiles systemically and locally.Our data support the development of CpG-PEGs as a new therapeutic agent that can be systemically administered to modulate immune responses and the microenvironment in tumor tissues.
Keywords: CpG-ODN; PEG; immune modulation; systemic administation

Formulation Stabilization and Disaggregation of Bevacizumab, Ranibizumab and Aflibercept in Dilute Solutions by Steven A. Giannos; Edward R. Kraft; Zhen-Yang Zhao; Kevin H. Merkley; Jiyang Cai (1-15).
Studies were conducted to investigate dilute solutions of the monoclonal antibody (mAb) bevacizumab, mAb fragment ranibizumab and fusion protein aflibercept, develop common procedures for formulation of low concentration mAbs and identify a stabilizing formulation for anti-VEGF mAbs for use in in vitro permeation studies.Excipient substitutions were screened. The most stabilizing formulation was chosen. Standard dilutions of bevacizumab, ranibizumab and aflibercept were prepared in PBS, manufacturer’s formulation, and the new formulation. Analysis was by SE-HPLC and ELISA. Stability, disaggregation and pre-exposure tests were studied.When Avastin, Lucentis and Eylea are diluted in PBS or manufacturer’s formulation, there is a 40–50% loss of monomer concentration and drug activity. A formulation containing 0.3% NaCl, 7.5% trehalose, 10 mM arginine and 0.04% Tween 80 at a pH of 6.78 stabilized the mAbs and minimized the drug loss. The formulation also disaggregates mAb aggregation while preserving the activity. Degassing the formulation increases recovery.We developed a novel formulation that significantly stabilizes mAbs under unfavorable conditions such as low concentration or body temperature. The formulation allows for tissue permeation experimentation. The formulation also exhibits a disaggregating effect on mAbs, which can be applied to the manufacture/packaging of mAbs and bioassay reagents.
Keywords: aflibercept; bevacizumab; ELISA; ranibizumab; SE-HPLC

To understand hydrolysis and alcoholysis of polyvinylpyrrolidone-co-vinylacetate (PVPVA) during formulation and storage, elucidate the reaction mechanism, establish an intrinsic kinetic model, and apply this model coupled with GastroPlus™ modeling to predict the amount of PVPVA degradation in vivo.The experimental approach includes the detection of the polymer reaction by solution nuclear magnetic resonance (NMR) and the measurement of reaction product concentration via gas chromatography (GC). The theoretical approach includes the establishment of the intrinsic kinetic model and the application of GastroPlus™ to predict the degree of PVPVA degradation.The kinetic model established is a first order reaction between PVPVA and 2-propanol (IPA) or water under an acidic condition. The application of this kinetic model shows that between 1.7 and 6.8 mg of degradant is formed in the GI tract for a 850 mg dose of PVPVA.The results from this application provide valuable input for process development and the risk analysis of the degradation of PVPVA.
Keywords: alcoholysis; degradation; hydrolysis; modeling; PVPVA; reaction kinetics

The Placental Barrier: the Gate and the Fate in Drug Distribution by Nino Tetro; Sonia Moushaev; Miriam Rubinchik-Stern; Sara Eyal (1-16).
Optimal development of the embryo and the fetus depends on placental passage of gases, nutrients, hormones, and waste products. These molecules are transferred across the placenta via passive diffusion, carrier-mediated cellular uptake and efflux, and transcytosis pathways. The same mechanisms additionally control the rate and extent of transplacental transfer of drugs taken by the pregnant mother. Essentially all drugs cross the placenta to a certain extent, and some accumulate in the placenta itself at levels that can even exceed those in maternal plasma. Hence, even drugs that are not efficiently transferred across the placenta may indirectly affect fetal development by interfering with placental function. In this article, we describe key properties of the placental barrier and their modulation by medications. We highlight implications for pharmacotherapy and novel approaches for drug delivery in pregnant women and their fetuses.
Keywords: drug transporters; maternal-fetal pharmacology; placenta; placental transfer; pregnancy