Biodistribution Profile Research Articles

Gemcitabine-loaded Folic Acid Tagged Liposomes: Improved Pharmacokinetic and Biodistribution Profile.

Gemcitabine (GEM) is found effective in the treatment of many solid tumors. However, its use is restricted due to its small circulation half-life, fast metabolism and low capacity for selective tumor uptake. Folate receptors (FRs) have been recognized as cellular surface markers, which can be used for cancer targeting. PEGylated liposomes decorated with folic acid have been investigated for several anticancer agents not only to extend plasma half-life but also for tumor targeting via folic acid receptors which overexpressed on tumor cell surface. Therefore, the objective of the present study was to prepare GEM-loaded folic acid tagged liposomes to improve the pharmacokinetics and tumor distribution of GEM. The blank folate-targeted liposomes composed of HSPC/DSPE-mPEG2000/DSPE-mPEG-Folic acid were prepared first by thin film hydration technique. GEM was then loaded into liposomes by remote loading technique. The optimized liposomal formulations were evaluated in vitro for GEM release using dialysis technique, HeLa cell uptake using FACS technique, and cytotoxicity using MTT dye reduction assay. The comparative in vivo pharmacokinetic and biodistribution characteristics of radiolabeled (99mTc-labeled) plain GEM solution, and all liposomal formulations (conventional:CLs; stealth: SLs; folate targeted: FTLs) were evaluated in mice model. GEM-loaded FTLs showed sustained release profile, efficient uptake by HeLa cells and greater cytotoxicity. Further, FTLs displayed significantly improved pharmacokinetics, and biodistribution profile of loaded GEM. In conclusion, the developed GEM-loaded folic acid receptor-targeted liposomal formulation could be a promising and potential alternative formulation for further development.

A multifunctional drug nanocarrier for efficient anticancer therapy

So far, the success of anticancer nanomedicines has been moderate due to their lack of adequate targeting properties and/or to their difficulties for penetrating tumors. Here we report a multifunctional drug nanocarrier consisting of hyaluronic acid nanocapsules conjugated with the tumor homing peptide tLyp1, which exhibits both, dual targeting properties (to the tumor and to the lymphatics), and enhanced tumor penetration. Data from a 3D co-culture in vitro model showed the capacity of these nanocapsules to interact with the NRP1 receptors over-expressed in cancer cells. The targeting capacity of the nanocapsules was evidenced in orthotopic lung cancer-bearing mice, using docetaxel as a standard drug. The results showed a dramatic accumulation of docetaxel in the tumor (37-fold the one achieved with Taxotere®). This biodistribution profile correlated with the high efficacy shown in terms of tumor growth regression and drastic reduction of metastasis in the lymphatics. When efficacy was validated in a pancreatic patient-derived tumor, the nanocapsule's activity was comparable to that of a dose ten times higher of Abraxane®. Multi-functionality was found to be the key to the success of this new therapy.

A Rationally Designed Novel Polymer for Safe and Synergistic Delivery of High Dose Bortezomib, Pomalidomide/Lenalidomide, and Dexamethasone for Multiple Myeloma

Abstract Introduction. Synergistic delivery of free drugs is highly challenging due to each drug's unique pharmacokinetics and biodistribution profiles. The standard of care Bortezomib, Pomalidomide/Lenalidomide, and Dexamethasone only demonstrates synergy in a specific concentration window. This specific concentration window has been proven difficult to reach using free drugs. Whereas the Bortezomib, Pomalidomide/Lenalidomide, and Dexamethasone drug combination is the standard of care for patients, an improved method to deliver drugs more specifically to the tumor in higher concentration and at their synergistic ratios would greatly improve the clinical outcome of Multiple Myeloma patients treatments. Methods and Results. We developed a novel 10 nm biodegradable bottlebrush polymer made of various PEG macromonomers conjugated to clinically used Myeloma drugs, including Bortezomib, Pomalidomide, Lenalidomide, and Dexamethasone. By combining the different macromonomer-drug conjugates together, we defined the most synergistic drug ratio by using the Chou-Talalay method in MM.1S, and KMS11 cell lines. Before evaluating the efficacy of the combination therapy in-vivo, we determined the maximum tolerated dose (MTD) for the Bortezomib bottlebrush alone by monitoring body weight loss, performing H&E staining in all major organs, and performing blood test panels. We successfully injected up to 25x the tolerated dose of free Bortezomib (0.75 mg/kg once a week) with our novel bottlebrush polymer conjugated to Bortezomib (18.75 mg/kg) without signs of toxicity in healthy Balb/c mice. We next evaluated the efficacy of Bortezomib bottlebrush in an orthotopic model of MM.1SGFP+/Luc+ Multiple Myeloma. We determined by fluorescence imaging of harvested organs and by flow cytometry that approx. 5% of the injected dose of bottlebrush Bortezomib (0.95 mg/kg) accumulated in the bone marrow. As a result, this improved and safer delivery technique allowed us to increase by 12 and 10 days the long-term survival of the MM.1SGFP+/Luc+ SCID mice, as compared to free Bortezomib (0.75 mg/kg) and low dose Bortezomib bottlebrush (0.75 mg/kg), respectively (p-value = 0.038, Mann-Whitney). In order to improve the long-term survival and to reach a complete response, we are currently investigating the use of the combination of the 3 drugs: Bortezomib, Pomalidomide, Dexamethasone simultaneously loaded in our bottlebrush at synergistic ratios and comparing the efficacy and toxicity of this combination to the 3 different single loaded bottlebrushes and to the efficacity and toxicity of the free drug combination. Conclusion. In conclusion, we developed a novel polymer enabling the controlled loading of multiple drugs at their optimal synergistic ratios. In addition, we demonstrated that the conjugation of the drug on our polymer enables the safe delivery of a higher tolerated dose in the body compared to treatments using free drugs and provided improved in-vivo therapeutic outcomes. Disclosures Ghobrial: Janssen: Consultancy; BMS: Consultancy; Celgene: Consultancy; Takeda: Consultancy.

Development of self-assembled multi-arm polyrotaxanes nanocarriers for systemic plasmid delivery in vivo

Polyrotaxane (PRX) is a promising supramolecular carrier for gene delivery. Classic PRX exhibits a linear structure in which the amine-functionalized α-cyclodextrin (CD) is threaded along the entire polyethylene glycol (PEG) backbone. While promising in vitro, the absence of free PEG moieties after CD threading compromised the in vivo implementation, due to the unfavorable pharmacokinetics (PK) and biodistribution profile. Herein, we developed a multi-arm PRX nanocarrier platform, which has been designed for protective nucleic acid encapsulation, augmented biodistribution and PK, and suitable for intravenous (IV) administration. A key design was to introduce cationic CD rings onto a multi-arm PEG backbone in a spatially selective fashion. The optimal structural design was obtained through iterative rounds of experimentation to determine the appropriate type and density of cationic charge on CD ring, the degree of PEGylation, the size and structure of polymer backbone, etc. This allowed us to effectively deliver large size reporter and therapeutic plasmids in cancer mouse models. Post IV injection, we demonstrated that our multi-arm polymer design significantly enhanced circulatory half-life and PK profile compared to the linear PRX. We continued to use the multi-arm PRX to formulate a therapeutic plasmid encoding an immunomodulatory cytokine, IL-12. When tested in a colon cancer syngeneic mouse model with same background, the IL-12 plasmid was protected by the multi-arm PRX and delivered through the tail vein to the tumor site, leading to a significant tumor inhibition effect. Moreover, our delivery system was devoid of major systemic toxicity.

Metallacarboranes on the Road to Anticancer Therapies: Cellular Uptake, DNA Interaction, and Biological Evaluation of Cobaltabisdicarbollide [COSAN

After uptake by U87 MG and A375 cancer cells, cobaltabisdicarbollide [COSAN]- distributes between membrane and nucleus and presents no relevant cytotoxicity against both cell lines even for long incubation times. The cytotoxicity of Na[COSAN] was also tested towards one normal cell line, the V79 fibroblasts, in order to ascertain the noncytotoxic profile of the compound. As the cell's nucleus contains DNA, the interaction between [COSAN]- and double-stranded calf thymus DNA (CT-dsDNA) has been investigated. There is a strong interaction between both molecules forming a nanohybrid CT-dsDNA-[COSAN] biomaterial, which was fully characterized. Moreover, Na[COSAN] shows characteristic redox peaks ascribed to the oxidation/reduction of Co3+/2+ at a formal potential of -1.444 V and it can be accumulated at a surface-immobilized DNA layer of glassy carbon electrodes. The equilibrium surface-binding constants (Kox /Kred ), which confirm that [COSAN]- interacts with DNA by an intercalative or electrostatic mode, depending on the ionic strength of the solution, were estimated. In addition, high binding affinity of Na[COSAN] to proteins was observed by 11 B{1 H} NMR and confirmed in vivo. Finally, biodistribution studies of [COSAN]- in normal mice were run. After administration, Na[COSAN] was distributed into many organs but mainly accumulated in the reticuloendothelial system (RES), including liver and spleen. After 1 h, the formation of aggregates by plasma protein interaction plays a role in the biodistribution profile; the aggregates accumulate mostly in the lungs. Na[COSAN], which displays low toxicity and high uptake by relevant cancer cells accumulating boron within the nucleus, could act as a suitable compound for further developments as boron neutron capture therapy (BNCT) agents.

Triply Loaded Nitroxide Brush-Arm Star Polymers Enable Metal-Free Millimetric Tumor Detection by Magnetic Resonance Imaging.

Nitroxides occupy a privileged position among plausible metal-free magnetic resonance imaging (MRI) contrast agents (CAs) due to their inherently low-toxicity profiles; nevertheless, their translational development has been hindered by a lack of appropriate contrast sensitivity. Nanostructured materials with high nitroxide densities, where each individual nitroxide within a macromolecular construct contributes to the image contrast, could address this limitation, but the synthesis of such materials remains challenging. Here, we report a modular and scalable synthetic approach to nitroxide-based brush-arm star polymer (BASP) organic radical CAs (ORCAs) with high nitroxide loadings. The optimized ∼30 nm diameter "BASP-ORCA3" displays outstanding T2 sensitivity with a very high molecular transverse relaxivity ( r2 > 1000 mM-1 s-1). BASP-ORCA3 further exhibits excellent stability in vivo, no acute toxicity, and highly desirable pharmacokinetic and biodistribution profiles for longitudinal detection of tumors by MRI. When injected intravenously into mice bearing subcutaneous plasmacytomas, BASP-ORCA3 affords distinct in vivo visualization of tumors on translationally relevant time scales. Leveraging its high sensitivity, BASP-ORCA3 enables efficient mapping of tumor necrosis, which is an important biomarker to predict therapeutic outcomes. Moreover, BASP-ORCA3 allows for detection of millimetric tumor implants in a disseminated murine model of advanced-stage human ovarian cancer that possess genetic, histological, and vascular characteristics that are similar to those seen in patients. This work establishes BASP-ORCA3 as a promising metal-free spin contrast agent for MRI.

Radiolabeled Molecular Imaging Probes for the In Vivo Evaluation of Cellulose Nanocrystals for Biomedical Applications.

Cellulose nanocrystals (CNCs) have remarkable potential to improve the delivery of diagnostic and therapeutic agents to tumors; however, the in vivo studies on CNC biodistribution are still limited. We developed CNC-based imaging probes for the in vitro and in vivo evaluation using two labeling strategies: site-specific hydrazone linkage to the terminal aldehyde of the CNC and nonsite-specific activation using 1,1'-carbonyldiimidazole (CDI). The in vivo behavior of unmodified CNC, DOTA-CNC (ald.), and DOTA-CNC (OH) was investigated in healthy and 4T1 breast cancer mouse models. They displayed good biocompatibility in cell models. Moreover, the biodistribution profile and SPECT/CT imaging confirmed that the accumulation of 111In-labeled DOTA-CNC (ald.) and 111In-DOTA-CNC (OH) was primarily in hepatic, splenic, and pulmonary ducts in accordance with the clearance of nontargeted nanoparticles. The developed CNC imaging probes can be used to obtain information with noninvasive imaging on the behavior in vivo to guide structural optimization for targeted delivery.

Intraperitoneal delivery of NanoOlaparib for disseminated late-stage cancer treatment.

BackgroundPARP inhibitors, such as Olaparib, have advanced the treatment of ovarian cancer by providing patients with an effective and molecularly-targeted maintenance therapy. However, all orally-administered drugs, including Olaparib, must undergo first-pass metabolism. In contrast, a nanoparticle delivery system has the advantage of administering Olaparib directly into the peritoneal cavity for local treatment. Consequently, we sought to optimize the sustained-release formulation NanoOlaparib, previously deemed effective as an intravenous solid tumor treatment, for the local treatment of disseminated disease via intraperitoneal (i.p.) therapy.MethodsThe tumor cell line 404, which was derived from a Brca2−/−, Tp53−/−, Pten−/− genetically engineered mouse model, exhibited high sensitivity to Olaparib in vitro. It was chosen for use in developing an i.p. spread xenograft for testing nanotherapy efficacy in vivo. NanoOlaparib as a monotherapy or in combination with cisplatin was compared to oral Olaparib alone or in combination using two different dose schedules. A pilot biodistribution study was performed to determine drug accumulation in various organs following i.p. administration.ResultsDaily administration of NanoOlaparib reduced tumor growth and decreased the variability of the treatment response observed with daily oral Olaparib administration. However, systemic toxicity was observed in both the NanoOlaparib and vehicle (empty nanoparticle) treated groups. Scaling back the administration to twice weekly was well tolerated up to 100 mg/kg but reduced the effect on tumor growth. Biodistribution profiles indicated that NanoOlaparib began accumulating in tissues within an hour of administration and persisted for at least 72 hours after a single dose, exiting the peritoneal cavity faster than expected.ConclusionNanoOlaparib must be modified for use against disseminated disease. Future avenues to develop NanoOlaparib as an i.p. therapy include a modified surface-coating to retain it in the peritoneal cavity and prevent entry into systemic circulation, in addition to targeting moieties for localization in tumor cells.

Synthesis and Preclinical Evaluation of the First Carbon-11 Labeled PET Tracers Targeting Substance P1-7.

Two potent SP1–7 peptidomimetics have been successfully radiolabeled via [11C]CO2-fixation with excellent yields, purity, and molar activity. l-[11C]SP1–7-peptidomimetic exhibited promising ex vivo biodistribution profile. Metabolite analysis showed that l-[11C]SP1–7-peptidomimetic is stable in brain and spinal cord, whereas rapid metabolic degradation occurs in rat plasma. Metabolic stability can be significantly improved by substituting l-Phe for d-Phe, preserving 70% more of intact tracer and resulting in better brain and spinal cord tracer retention. Positron emission tomography (PET) scanning confirmed moderate brain (1.5 SUV; peak at 3 min) and spinal cord (1.0 SUV; peak at 10 min) uptake for l- and d-[11C]SP1–7-peptidomimetic. A slight decrease in SUV value was observed after pretreatment with natural peptide SP1–7 in spinal cord for l-[11C]SP1–7-peptidomimetic. On the contrary, blocking using cold analogues of l- and d-[11C]tracers did not reduce the tracers’ brain and spinal cord exposure. In summary, PET scanning of l- and d-[11C]SP1–7-peptidomimetics confirms rapid blood–brain barrier and blood–spinal-cord barrier penetration. Therefore, further validation of these two tracers targeting SP1–7 is needed in order to define a new PET imaging target and select its most appropriate radiopharmaceutical.

Exosomes in perspective: a potential surrogate for stem cell therapy.

Exosomes as a unique subtype of small extracellular vesicles (sEVs) have attracted increasing interest in recent years in the fields of mesenchymal stromal cell (MSC) research. Studies have confirmed that exosomes derived from MSCs preserve immunosuppressive phenotype and can mimic therapeutic benefits of their parent cells. This review briefly summarizes most recent findings on the potential of exosomes as an alternative of therapeutic MSCs, focusing on the role of MSCs and their secreted exosomes in regulation of immune cells, preclinical and clinical evidence of therapeutic outcomes of MSC exosomes, and the biodistribution and pharmacokinetic profile of systemically administered exosomes. It is appreciated that exosomes from MSCs of different sources have variable contents including inflammatory mediators, tropic factors, signaling molecules, and nucleic acids (DNA, mRNA, microRNA and long non-coding RNA). Diverse functions of exosomes derived from different sources are expected. More importantly, exosomes isolated in vitro may not mirror that from in vivo, where donor MSCs are exposed to specific disease or injury-related conditions. Simulating in vivo microenvironment by pretreatment of MSCs with relevant chemical mediators may lead to their secretion of therapeutically more efficient exosomes/sEVs. However, we know very little about the key molecules involved and the differences between exosomes released under different conditions. These issues would be of tremendous interest to preclinical research that pursues exosome biology-underlain therapeutic mechanisms of MSCs. Further studies are expected to demonstrate the superiority of MSC-derived exsomes/sEVs as a pharmaceutical entity with regard to efficacy, safety, and practicability.

Ultrasmall targeted nanoparticles with engineered antibody fragments for imaging detection of HER2-overexpressing breast cancer

Controlling the biodistribution of nanoparticles upon intravenous injection is the key to achieving target specificity. One of the impediments in nanoparticle-based tumor targeting is the inability to limit the trafficking of nanoparticles to liver and other organs leading to smaller accumulated amounts in tumor tissues, particularly via passive targeting. Here we overcome both these challenges by designing nanoparticles that combine the specificity of antibodies with favorable particle biodistribution profiles, while not exceeding the threshold for renal filtration as a combined vehicle. To that end, ultrasmall silica nanoparticles are functionalized with anti-human epidermal growth factor receptor 2 (HER2) single-chain variable fragments to exhibit high tumor-targeting efficiency and efficient renal clearance. This ultrasmall targeted nanotheranostics/nanotherapeutic platform has broad utility, both for imaging a variety of tumor tissues by suitably adopting the targeting fragment and as a potentially useful drug delivery vehicle.

Radiolabeling of Preformed Niosomes with [99mTc]: In Vitro Stability, Biodistribution, and In Vivo Performance.

Nanocarriers radiolabeled with [99mTc] can be used for diagnostic imaging and radionuclide therapy, as well as tracking their pharmacokinetic and biodistribution characteristics. Due to the advantages of niosomes as an ideal drug delivery system, in this study, the radiolabeling procedure of niosomes by [99mTc]-HMPAO complexes was investigated and optimized. Glutathione (GSH)-loaded niosomes were prepared using a thin-film hydration method. To label the niosomes with [99mTc], the preformed GSH-loaded niosomes were incubated with the [99mTc]-HMPAO complex and were characterized for particle size, size distribution, zeta potential, morphology, and radiolabeling efficiency (RE). The effects of GSH concentration, incubation time, incubation temperature, and niosomal composition on RE were investigated. The biodistribution profile and in vivo SPECT/CT imaging of the niosomes and free [99mTc]-HMPAO were also studied. Based on the results, all vesicles had nano-sized structure (160-235nm) and negative surface charge. Among the different experimental conditions that were tested, including various incubation times, incubation temperatures, and GSH concentrations, the optimum condition that resulted in a RE of 92% was 200-mM GSH and 15-min incubation at 40°C. The in vitro release study in plasma showed that about 20% of radioactivity was released after 24h, indicating an acceptable radiolabeling stability in plasma. The biodistribution of niosomes was clearly different from the free radiolabel. Niosomes carrying radionuclide were successfully used for tracking the in vivo disposition of these carriers and SPECT/CT imaging in rats. Furthermore, biodistribution studies in tumor-bearing mice revealed higher tumor accumulation of the niosomal formulation as compared with [99mTc]-HMPAO.

Controlled non-invasive iontophoretic delivery of triamcinolone acetonide amino acid ester prodrugs into the posterior segment of the eye

This study investigated short duration transscleral iontophoretic delivery of four triamcinolone acetonide (TA) amino acid ester prodrugs (TA-AA) (alanine, Ala; arginine, Arg; isoleucine, Ile and lysine, Lys) using whole porcine eyes globes in vitro. Post-iontophoretic biodistribution of TA was quantified by UHPLC-MS/MS in the different ocular compartments (cornea, aqueous humor, sclera, ciliary body, choroid and retinal pigmented epithelium (RPE), neural retina and vitreous humor). Transscleral iontophoresis (3 mA/cm2 for 10 min) increased total drug delivery of the TA-AA prodrugs by 14-30-fold as compared to passive diffusion. The TA-AA prodrugs had distinct biodistribution profiles – the penetration depth achieved was dependent on their physicochemical properties (e.g. lipophilicity for TA-Ile) and susceptibility to hydrolysis (e.g. TA-Arg). Intraocular drug distribution was also influenced by prodrug binding to melanin (TA-Lys). Interestingly, under conditions of equivalent charge (6 mA/cm2 for 5 min vs. 1.5 mA/cm2 for 20 min, i.e. 1.44 C respectively) the longer duration (20 min) at lower current density resulted in ∼6 times more TA delivery into the vitreous humor. Overall, the study provided further evidence of the potential of transscleral iontophoresis for the non-invasive treatment of posterior segment inflammatory diseases.

Synthesis of novel gallium-68 labeled rhodamine: A potential PET myocardial perfusion agent

Myocardial perfusion imaging (MPI) is one of the most commonly performed investigations in nuclear medicine studies. Due to the physical properties of the positron emitter gallium-68 (68Ga) and its availability from 68Ge/68Ga generator, together with the well-known coordination chemistry, we have synthesized 68Ga-NOTA- and 68Ga-NODAGA-rhodamine conjugates using a straightforward and a one-step simple reaction. Radiochemical yields were greater than 95% (decay corrected), with total synthesis time of less than 30 min. Radiochemical purities were always greater than 98% as assessed by TLC and HPLC. These synthetic approaches hold considerable promise as simple method for 68Ga-rhodamine conjugates preparation, with high radiochemical yield and purity. Biodistribution studies in normal Fischer rats at 60 min post-injection, demonstrated significant (~3% ID/g) uptake and favorable biodistribution profile for 68Ga-NOTA-rhodamine over 68Ga-NODAGA-rhodamine conjugate. These results demonstrate that 68Ga-NOTA-rhodamine conjugate may be useful as probe for the PET evaluation of myocardial perfusion.

Zebrafish (Danio rerio) model as an early stage screening tool to study the biodistribution and toxicity profile of doxorubicin-loaded mixed micelles

Doxorubicin (DOX) hydrochloride is a powerful anthracycline antibiotic used for the treatment of various types of malignancies, particularly ovarian and metastatic breast cancer. However, DOX presents severe side effects, such as hepatotoxicity, nephrotoxicity, dose-limiting myelosuppression, brain damage and cardiotoxicity. A liposomal formulation, Doxil®, was approved by the FDA, which has managed to reduce the number of cardiac events in patients with metastatic breast cancer. However, in comparison to free DOX, Doxil® has not shown significant improvements regarding survival. We have previously designed DOX-loaded mixed micelles (MMDOX) composed of D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and Tetronic® T1107. To assess the potential toxic effects of this novel formulation, in this work the zebrafish (Danio rerio) model was used to evaluate its in vivo toxicity and teratogenicity. This study evaluated and compared the effects of DOX exposure from different formulations (free DOX, MMDOX and Doxil®) on the swimming activity, morphological alterations, cardiac rhythm, lethality rate and DOX biodistribution. MMDOX showed lower lethal effects, morphological alterations and neurotoxic effects than the free drug. This study shows the potential of the MMDOX to be an effective DOX-delivery system because it could reduce the side effects.

Abstract 4116: Rapid imaging of tumor cell death in vivo using C2Am

Abstract Cell death is an important target for imaging the early response of tumors to treatment. We describe here the validation of C2Am, a phosphatidylserine-binding agent based on the C2A domain of synaptotagmin-I, for detecting tumor cell death in vivo. Methods: The capability of (99m)Technetium-, (111)Indium-labelled or near- infrared fluorophore-labelled derivatives of C2Am for imaging tumor cell death was evaluated in implanted and genetically engineered [Fig.1] mouse models of lymphoma and in a human colorectal xenograft, using single photon CT (SPECT) and planar near-infrared fluorescence imaging, respectively [1,2]. Results: (99m)Tc-C2Am and (111)In-C2Am showed favorable biodistribution profiles, with predominantly renal clearance and low nonspecific retention in the spleen and liver at 24 h after probe administration. (99m)Tc-C2Am and (111In)-C2Am generated tumor-to-muscle ratios in drug-treated tumors of 4.3× and 2.2×, respectively, at 2 h and 7.3× and 4.1×, respectively, at 24 h after administration. A fluorophore-labelled C2Am derivative also showed predominantly renal clearance and high specificity and sensitivity for detecting low levels of tumor cell death (<5%). There was a significant correlation (R=0.9) between fluorescently labelled C2Am binding and histologic markers of cell death (cleaved caspase-3); no such correlation was observed with a site-directed mutant of C2Am that does not bind phosphatidylserine (iC2Am). Conclusions: Given the favorable biodistribution profile of radiolabelled C2Am derivatives, and their ability to produce rapid and cell death-specific image contrast, these agents have potential for clinical translation, particularly as PET tracers. We have initiated GMP manufacture and toxicology studies required for a Phase 1 trial.

Linear Cyclodextrin Polymer Prodrugs as Novel Therapeutics for Niemann-Pick Type C1 Disorder

Niemann-Pick Type C1 disorder (NPC) is a rare lysosomal storage disease characterized by the accumulation of cholesterol in lysosomes. NPC has no FDA approved treatments yet, however 2-hydroxypropyl-β-cyclodextrin (HPβCD) has shown efficacy for treating the disease in both mouse and feline NPC models and is currently being investigated in late stage clinical trials. Despite promising results, therapeutic use of HPβCD is limited by the need for high doses, ototoxicity and intrathecal administration. These limitations can be attributed to its poor pharmacokinetic profile. In the attempt to overcome these limitations, we have designed a β-cyclodextrin (βCD) based polymer prodrugs (ORX-301) for an enhanced pharmacokinetic and biodistribution profile, which in turn can potentially provide an improved efficacy at lower doses. We demonstrated that subcutaneously injected ORX-301 extended the mean lifespan of NPC mice at a dosage 5-fold lower (800 mg/kg, body weight) the HPβCD dose proven efficacious (4000 mg/kg). We also show that ORX-301 penetrates the blood brain barrier and counteracts neurological impairment. These properties represent a substantial improvement and appear to overcome major limitations of presently available βCD-based therapy, demonstrating that this novel prodrug is a valuable alternative/complement for existing therapies.

Scavenging of reactive oxygen and nitrogen species with nanomaterials.

Reactive oxygen and nitrogen species (RONS) are essential for normal physiological processes and play important roles in cell signaling, immunity, and tissue homeostasis. However, excess radical species are implicated in the development and augmented pathogenesis of various diseases. Several antioxidants may restore the chemical balance, but their use is limited by disappointing results of clinical trials. Nanoparticles are an attractive therapeutic alternative because they can change the biodistribution profile of antioxidants, and possess intrinsic ability to scavenge RONS. Herein, we review the types of RONS, how they are implicated in several diseases, and the types of nanoparticles with inherent antioxidant capability, their mechanisms of action, and their biological applications.

Pharmacology study of a chimeric decoy receptor trap fusion protein on retina neovascularization by dual blockage of VEGF and FGF-2

BackgroundClinical anti-vascular epithelial growth factor (VEGF) therapy trials faced a major challenge due to upregulated expression of other pro-angiogenic factors, such as fibroblast growth factor-2 (FGF-2). RC28, a novel recombinant dual decoy receptor IgG1 Fc-fusion protein, can block VEGFA and FGF-2 simultaneously. It is designed for the treatment of neovascular age-related macular degeneration and other pathological ocular neovascularization. The present study investigated the prevention efficacy of RC28 on choroidal neovascularization (CNV) in a monkey model and compared to the other mono VEGF antagonists; biodistribution and pharmacokinetics performance were also investigated. MethodsELISA and endothelial cell proliferation, migration, and tubule formation assay evaluated the bioactivity of RC28 in vitro, and an initial comparison was made among the mono target antagonists, Bevacizumab (Avastin), Ranibizumab (Lucentis), Aflibercept (EYLEA), Conbercept (KH902), and Ranibizumab (Lucentis). Laser-induced CNV in monkeys, and both VEGF and FGF-2 serum levels were detected in animals before and after the CNV model were induced. RC28 prevention efficacy was compared to other VEGF antagonists on CNV with respect to the incidence of CNV and several ophthalmic examinations. Ocular and systemic levels of RC28 were analyzed by 89Zr-labeled RC28 after single intravitreal administration for the biodistribution and pharmacokinetic profiles. ResultsRC28 is a unique fusion protein with high affinity to both VEGF and FGF-2, and beneficial to in vitro and in vivo bioactivity. The in vivo pharmacological studies demonstrated that the incidence of CNV formation was largely reduced in RC28 treatment groups with a low dosage as compared to other VEGF antagonist control groups. Furthermore, traces of RC28 were detected as dispersing from eyeballs to the liver after 20 days, and a prolonged half-time pharmacokinetic profile was exhibited.

The systematic evaluation of size-dependent toxicity and multi-time biodistribution of gold nanoparticles.

As a promising nanomaterial, gold nanoparticles (Au NPs) have been widely applied in diagnosis, drug and gene delivery, and photothermal therapy. However, the toxicity and biodistribution profile of differently sized Au NPs still remains controversial and incomplete, thus hindering their further applications. Herein, a systematic evaluation of size effect on toxicity and multi-time (from 4 h to 90 days) biodistribution of Au NPs ranging from 6.2 nm to 61.2 nm was conducted. The in vitro toxicity by MTT assays manifested that toxicity could be distinctly observed and increased with size decreasing when the dose of Au NPs reached up to a certain amount (1 mM). Subsequently, the corresponding toxicity mechanism was further studied via reactive oxygen species assay kit and the results indicated that Au NPs with various sizes would induce different oxidative stress which was accountable for the ultimate toxicity. Furthermore, the result of the biodistribution showed that Au NPs with larger sizes (42.5 and 61.2 nm) accumulated mainly in liver and spleen while little or none were found in heart, kidney and lung. Dissimilarly, smaller ones (6.2 and 24.3 nm) were distributed not only in liver and spleen but also in other organs. Additionally, most of the Au NPs were excreted out in less than 30 days, whereas there were still bits of remains in liver and spleen up to 90 days, especially for the 42.5 and 61.2 nm Au NPs. These findings are meaningful for the design of the Au NPs in the biomedical fields.