Showing papers in "Molecular Pharmaceutics in 2010"
TL;DR: The novel developments described here may revise the classical outlook that NPs are passive delivery vehicles, in favor of responsive, sensing vehicles that use environmental cues to achieve maximal drug potency.
Abstract: First-generation nanoparticles (NPs) have been clinically translated as pharmaceutical drug delivery carriers for their ability to improve on drug tolerability, circulation half-life, and efficacy. Toward the development of the next-generation NPs, researchers have designed novel multifunctional platforms for sustained release, molecular targeting, and environmental responsiveness. This review focuses on environmentally responsive mechanisms used in NP designs, and highlights the use of pH-responsive NPs in drug delivery. Different organs, tissues, and subcellular compartments, as well as their pathophysiological states, can be characterized by their pH levels and gradients. When exposed to these pH stimuli, pH-responsive NPs respond with physicochemical changes to their material structure and surface characteristics. These include swelling, dissociating or surface charge switching, in a manner that favors drug release at the target site over surrounding tissues. The novel developments described here may ...
793 citations
TL;DR: Nanotheranostic systems are considered to be highly suitable systems for (pre-) clinical implementation, not only because they might assist in better understanding various important aspects of the drug delivery process, and in developing better drug delivery systems, but also because they Might contribute to realizing the potential of "personalized medicine", and to developing more effective and less toxic treatment regimens for individual patients.
Abstract: Nanomedicine formulations aim to improve the biodistribution and the target site accumulation of systemically applied (chemo-) therapeutics. Various different passively and actively targeted nanomedicines have been evaluated over the years, based e.g. on liposomes, polymers, micelles and antibodies, and a significant amount of (pre-) clinical evidence has been obtained showing that these 5−200 nm sized carrier materials are able to improve the therapeutic index of low-molecular-weight drugs. Besides for therapeutic purposes, however, nanomedicine formulations have also been more and more used for imaging applications, as well as, in recent years, for theranostic approaches, i.e. for systems and strategies in which disease diagnosis and therapy are combined. Potential applications of theranostic nanomedicine formulations range from the noninvasive assessment of the biodistribution and the target site accumulation of low-molecular-weight drugs, and the visualization of drug distribution and drug release at ...
370 citations
TL;DR: This publication critically reviews the literature that is relevant to oral human drug delivery and serves as a basis for the design of dissolution test methods and systems that are more representative of the human condition.
Abstract: Pharmaceutical solid oral dosage forms must undergo dissolution in the intestinal fluids of the gastrointestinal tract before they can be absorbed and reach the systemic circulation. Therefore, dissolution is a critical part of the drug-delivery process. The rate and extent of drug dissolution and absorption depend on the characteristics of the active ingredient as well as properties of the dosage form. Just as importantly, characteristics of the physiological environment such as buffer species, pH, bile salts, gastric emptying rate, intestinal motility, and hydrodynamics can significantly impact dissolution and absorption. While significant progress has been made since 1970 when the first compendial dissolution test was introduced (USP apparatus 1), current dissolution testing does not take full advantage of the extensive physiologic information that is available. For quality control purposes, where the question is one of lot-to-lot consistency in performance, using nonphysiologic test conditions that ma...
365 citations
TL;DR: This review summarizes the in vivo assessment-preliminary, preclinical, and clinical-of chemotherapeutics derived from camptothecin or a derivative, specifically in the context of biodistribution, dosing regimens, and pharmacokinetics with the desire of providing a useful source of comparative data.
Abstract: This review summarizes the in vivo assessment—preliminary, preclinical, and clinical—of chemotherapeutics derived from camptothecin or a derivative. Camptothecin is a naturally occurring, pentacyclic quinoline alkaloid that possesses high cytotoxic activity in a variety of cell lines. Major limitations of the drug, including poor solubility and hydrolysis under physiological conditions, prevent full clinical utilization. Camptothecin remains at equilibrium in an active lactone form and inactive hydrolyzed carboxylate form. The active lactone binds to DNA topoisomerase I cleavage complex, believed to be the single site of activity. Binding inhibits DNA religation, resulting in apoptosis. A series of small molecule camptothecin derivatives have been developed that increase solubility, lactone stability and bioavailability to varying levels of success. A number of macromolecular agents have also been described wherein camptothecin(s) are covalently appended or noncovalently associated with the goal of improv...
339 citations
TL;DR: The current study describes the impact of particle size and/or molecular targeting on the in vivo transport of block copolymer micelles (BCMs) in athymic mice bearing human breast cancer xenografts that express differential levels of EGF receptors (EGFR).
Abstract: The current study describes the impact of particle size and/or molecular targeting (epidermal growth factor, EGF) on the in vivo transport of block copolymer micelles (BCMs) in athymic mice bearing human breast cancer xenografts that express differential levels of EGF receptors (EGFR). BCMs with diameters of 25 nm (BCM-25) and 60 nm (BCM-60) were labeled with indium-111 (111In) or a fluorescent probe to provide a quantitative and qualitative means of evaluating their whole body, intratumoral, and subcellular distributions. BCM-25 was found to clear rapidly from the plasma compared to BCM-60, leading to an almost 2-fold decrease in their total tumor accumulation. However, the tumoral clearance of BCM-25 was delayed through EGF functionalization, enabling the targeted BCM-25 (T-BCM-25) to achieve a comparable level of total tumor deposition as the nontargeted BCM-60 (NT-BCM-60). Confocal fluorescence microscopy combined with MATLAB analyses revealed that NT-BCM-25 diffuses further away from the blood vessel...
329 citations
TL;DR: The sensitivity of DOX fluorescence intensity to DOX concentration, local microenvironment, and interaction with model cellular components is illustrated by fluorescence spectra of paired DOX/phospholipid,DOX/histone, DOx/DNA, and triple DOX /histone/DNA and DOX-loaded nanodroplet systems.
Abstract: Doxorubicin (DOX) is one of the most commonly used chemotherapeutic drugs and is a popular research tool due to the inherent fluorescence of the DOX molecule. After DOX injection, fluorescence imaging of organs or cells can provide information on drug biodistribution. Therapeutic and imaging capabilities combined in a DOX molecule make it an excellent theranostic agent. However, DOX fluorescence depends on a number of factors that should be taken into consideration when interpreting results of DOX fluorescence measurements. Discussing these problems is the main thrust of the current paper. The sensitivity of DOX fluorescence intensity to DOX concentration, local microenvironment, and interaction with model cellular components is illustrated by fluorescence spectra of paired DOX/phospholipid, DOX/histone, DOX/DNA, and triple DOX/histone/DNA and DOX/phospholipid/DNA systems. DOX fluorescence is dramatically quenched upon intercalation into the DNA; DOX fluorescence is also self-quenched at high concentratio...
308 citations
TL;DR: High-performance RGD-conjugated dendrimer-modified gold nanorods conjugated with arginine-glycine-aspartic acid (RGD) peptides exhibit great potential in applications such as tumor targeting, imaging, and selective photothermal therapy.
Abstract: Successful development of safe and effective nanoprobes for tumor targeting and selective therapy is a challenging task. Although gold nanorods(GNRs) have the potential to perform such a role, the toxicity of surfactant cetyltrimethylammonium bromides (CTAB) on their surfaces limits their applications. Here, polyamidoamine dendrimer was applied to replace CTAB molecules on the surface of gold nanorods. When the resultant dendrimer-modified gold nanorods conjugated with arginine-glycine-aspartic acid (RGD) peptides, they showed highly selective targeting and destructive effects on the cancer cells and solid tumors under near-infrared laser irradiation. Also, we successfully observed the disappearance of tumors implanted in four sample mice from test group of ten. High-performance RGD-conjugated dendrimer-modified GNR nanoprobes exhibit great potential in applications such as tumor targeting, imaging, and selective photothermal therapy.
306 citations
TL;DR: The 3D coculture system may serve as a valuable tool for developing drugs and formulations for the treatment of inflammatory bowel diseases, as well as for studying the interaction of xenobiotics and nanoparticles with the intestinal epithelial barrier in the state of inflammation.
Abstract: While epithelial cell culture models (e.g., Caco-2 cell line) are widely used to assess the absorption of drug molecules across healthy intestinal mucosa, there are no suitable in vitro models of the intestinal barrier in the state of inflammation. Thus development of novel drugs and formulations for the treatment of inflammatory bowel disease is largely bound to animal models. We here report on the development of a complex in vitro model of the inflamed intestinal mucosa, starting with the selection of suitable enterocyte cell line and proinflammatory stimulus and progressing to the setup and characterization of a three-dimensional coculture of human intestinal epithelial cells and immunocompetent macrophages and dendritic cells. In the 3D setup, controlled inflammation can be induced allowing the mimicking of pathophysiological changes occurring in vivo in the inflamed intestine. Different combinations of proinflammatory stimuli (lipopolysaccharides from Escherichia coli and Salmonella typhimurium, interleukin-1β, interferon-γ) and intestinal epithelial cell lines (Caco-2, HT-29, T84) were evaluated, and only Caco-2 cells were responsive to stimulation, with interleukin-1β being the strongest stimulator. Caco-2 cells responded to the proinflammatory stimulus with a moderate upregulation of proinflammatory markers and a slight, but significant, decrease (20%) of transepithelial electrical resistance (TEER) indicating changes in the epithelial barrier properties. Setting up the coculture model, macrophages and dendritic cells derived from periphery blood monocytes were embedded in a collagen layer on a Transwell filter insert and Caco-2 cells were seeded atop. Even in the presence of immunocompetent cells Caco-2 cells formed a tight monolayer. Addition of IL-1β increased inflammatory cytokine response more strongly compared to Caco-2 single culture and stimulated immunocompetent cells proved to be highly active in sampling apically applied nanoparticles. Thus the 3D coculture provides additional complexity and information compared to the stimulated single cell model. The coculture system may serve as a valuable tool for developing drugs and formulations for the treatment of inflammatory bowel diseases, as well as for studying the interaction of xenobiotics and nanoparticles with the intestinal epithelial barrier in the state of inflammation.
192 citations
TL;DR: The integrated diagnostic and therapeutic design of MFM nanomedicine potentially allows for image-guided, target-specific treatment of lung cancer.
Abstract: Polymeric micelles are emerging as a highly integrated nanoplatform for cancer targeting, drug delivery and tumor imaging applications. In this study, we describe a multifunctional micelle (MFM) system that is encoded with a lung cancer-targeting peptide (LCP), and encapsulated with superparamagnetic iron oxide (SPIO) and doxorubicin (Doxo) for MR imaging and therapeutic delivery, respectively. The LCP-encoded MFM showed significantly increased alpha(v)beta(6)-dependent cell targeting in H2009 lung cancer cells over a scrambled peptide (SP)-encoded MFM control as well as in an alpha(v)beta(6)-negative H460 cell control. (3)H-Labeled MFM nanoparticles were used to quantify the time- and dose-dependent cell uptake of MFM nanoparticles with different peptide encoding (LCP vs SP) and surface densities (20% and 40%) in H2009 cells. LCP functionalization of the micelle surface increased uptake of the MFM by more than 3-fold compared to the SP control. These results were confirmed by confocal laser scanning microscopy, which further demonstrated the successful Doxo release from MFM and accumulation in the nucleus. SPIO clustering inside the micelle core resulted in high T(2) relaxivity (>400 Fe mM(-1) s(-1)) of the resulting MFM nanoparticles. T(2)-weighted MRI images showed clear contrast differences between H2009 cells incubated with LCP-encoded MFM over the SP-encoded MFM control. An ATP activity assay showed increased cytotoxicity of LCP-encoded MFM over SP-encoded MFM in H2009 cells (IC(50) values were 28.3 +/- 6.4 nM and 73.6 +/- 6.3 nM, respectively; p < 0.005). The integrated diagnostic and therapeutic design of MFM nanomedicine potentially allows for image-guided, target-specific treatment of lung cancer.
191 citations
TL;DR: Indicating slow distribution of TPGS 1000 into the membrane, and in agreement with an intramembranal or intracellular side of action, Caco-2 cell monolayer experiments preincubated with T PGS 1000 produce stronger substrate inhibitory activity than those conducted by direct substrate and surfactant coapplication.
Abstract: Previous work conducted in our laboratories established the notion that TPGS 1000 (d-alpha-tocopheryl polyethylene glycol 1000 succinate), a nonionic surfactant, modulates P-glycoprotein (P-gp) efflux transport via P-gp ATPase inhibition. The current in vitro research using Caco-2 cells was conducted to further explore the P-gp ATPase inhibition mechanism. Using a monoclonal CD243 P-gp antibody shift assay (UIC2), we probed P-gp conformational changes induced via TPGS 1000. In the presence of TPGS 1000, UIC2 binding was slightly decreased. TPGS 1000 does not appear to be a P-gp substrate, nor does it function as a competitive inhibitor in P-gp substrate efflux transport. The reduction in UIC2 binding with TPGS 1000 was markedly weaker than with orthovanadate, data ruling out trapping P-gp in a transition state by direct interaction with one or both of the P-gp ATP nucleotide binding domains. An intracellular ATP depletion mechanism could be ruled out in the UIC2 assay, and by monitoring intracellular ATP levels in the presence of TPGS 1000. Indicating slow distribution of TPGS 1000 into the membrane, and in agreement with an intramembranal or intracellular side of action, Caco-2 cell monolayer experiments preincubated with TPGS 1000 produce stronger substrate inhibitory activity than those conducted by direct substrate and surfactant coapplication.
191 citations
TL;DR: The high uptake rates observed in vitro and the relatively low specificity in vivo imply that CPPs would be better suited for topical application in combination with cargoes which show passive targeting and dominate the pharmacokinetic behavior.
Abstract: Cell-penetrating peptides (CPPs) are able to penetrate the cell membrane carrying cargoes such as peptides, proteins, oligonucleotides, siRNAs, radioisotopes, liposomes, and nanoparticles. Consequently, many delivery approaches have been developed to use CPPs as tools for drug delivery. However, until now a systematic analysis of their in vivo properties including potential tumor binding specificity for drug targeting purposes has not been conducted. Ten of the most commonly applied CPPs were obtained by solid phase peptide synthesis and labeled with (111)In or (68)Ga. Uptake studies were conducted using a panel of six tumor cell lines of different origin. The stability of the peptides was examined in human serum. Biodistribution experiments were conducted in nude mice bearing human prostate carcinoma. Finally, positron emission tomography (PET) measurements were performed in male Wistar rats. The in vitro uptake studies revealed high cellular uptake values, but no specificity toward any of the cell lines. The biodistribution in PC-3 tumor-bearing nude mice showed a high transient accumulation in well-perfused organs and a rapid clearance from the blood. All of the CPPs revealed a relatively low accumulation rate in the brain. The highest uptake values were observed in the liver (with a maximal uptake of 51 %ID/g observed for oligoarginine (R(9))) and the kidneys (with a maximal uptake of 94 %ID/g observed for NLS). The uptake values in the PC-3 tumor were low at all time points, indicating a lack of tumor specific accumulation for all peptides studied. A micro-PET imaging study with (68)Ga-labeled penetratin, Tat and transportan(10) (TP(10)) confirmed the organ distribution data. These data reveal that CPPs do not show evidence for application in tumor targeting purposes in vivo. However, CPPs readily penetrate into most organs and show rapid clearance from the circulation. The high uptake rates observed in vitro and the relatively low specificity in vivo imply that CPPs would be better suited for topical application in combination with cargoes which show passive targeting and dominate the pharmacokinetic behavior. In conclusion, CPPs are suitable as drug carriers for in vivo application provided that their pharmacokinetic properties are also considered in design of CPP drug delivery systems.
TL;DR: Anti-carcinoembryonic antigen half-antibody conjugated lipid-polymer hybrid nanoparticles are synthesized and characterized and show enhanced cancer killing effect compared to the corresponding nontargeted nanoparticles.
Abstract: Current chemotherapy regimens against pancreatic cancer are met with little success as poor tumor vascularization significantly limits the delivery of oncological drugs. High-dose targeted drug delivery, through which a drug delivery vehicle releases a large payload upon tumor localization, is thus a promising alternative strategy against this lethal disease. Herein, we synthesize anti-carcinoembryonic antigen (CEA) half-antibody conjugated lipid−polymer hybrid nanoparticles and characterize their ligand conjugation yields, physicochemical properties, and targeting ability against pancreatic cancer cells. Under the same drug loading, the half-antibody targeted nanoparticles show enhanced cancer killing effect compared to the corresponding nontargeted nanoparticles.
TL;DR: These measurements together with a direct comparison with TAT peptides demonstrate that PAMAM dendrimers possess similar properties to these widely used cell-penetrating peptides and thanks to their chemical tunability may represent a valid alternative for drug and gene delivery.
Abstract: The ability of dendrimers to cross cell membranes is of much interest for their application in drug and gene delivery. Recent studies demonstrate that dendrimers are capable to enter cells by endocytosis, but the intracellular pathway following their internalization remains controversial. In this study we use confocal fluorescence microscopy to elucidate the intracellular trafficking properties of PAMAM dendrimers with high spatial and temporal resolution in living HeLa cells. Macromolecules of different chemical functionality (neutral, cationic and lipidated), size (from G2 up to G6) and surface charge are investigated and their internalization properties correlated with the molecular structure. Toxicity and internalization data are discussed that allow the identification of dendrimers maximizing intracellular uptake with the minimum effect on cell viability. Time-lapse imaging and colocalization assays with fluorescent biomarkers for endocytic vesicles demonstrate that dendrimers are internalized by bot...
TL;DR: It is concluded that the balance between the thermodynamic factors (enthalpy and entropy of mixing) in a ternary water-drug-polymer system is the important factor in determining which solid dispersion systems are susceptible to moisture-induced amorphous-amorphous phase separation.
Abstract: It has been previously observed that exposure to high relative humidity (RH) can induce amorphous-amorphous phase separation in solid dispersions composed of certain hydrophobic drugs and poly(vinylpyrrolidone) (PVP). The objective of this study was to investigate if this phenomenon occurred in solid dispersions prepared using less hygroscopic polymers. Drug-polymer miscibility was investigated before and after exposure to high RH using infrared (IR) spectroscopy and differential scanning calorimetry (DSC). PVP, poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA), and hypromellose acetate succinate (HPMCAS) were selected as model polymers, and felodipine, pimozide, indomethacin, and quinidine were selected as model drugs. Drug-polymer mixing at the molecular level was confirmed for all model systems investigated. Moisture-induced drug-polymer demixing was observed in felodipine-PVPVA, quinidine-PVP, quinidine-PVPVA, pimozide-PVPVA, and pimozide-HPMCAS systems, but was absent in the other HPMCAS dispersions and for indomethacin-PVPVA. It is concluded that the balance between the thermodynamic factors (enthalpy and entropy of mixing) in a ternary water-drug-polymer system is the important factor in determining which solid dispersion systems are susceptible to moisture-induced amorphous-amorphous phase separation. Systems with strong drug-polymer interactions and a less hygroscopic polymer will be less susceptible to moisture-induced phase separation, while more hydrophobic drugs will be more susceptible to this phenomenon even at low levels of sorbed moisture.
TL;DR: The physiologicalsolubility of "grease ball" molecules may be largely underestimated in in vitro solubility assays unless BDM is used, and the results herein indicate that the improvement obtained in BDM may be possible to predict from chemical features alone.
Abstract: A series of poorly soluble BCS class II compounds with “grease ball” characteristics were assessed for solubility and dissolution rate in biorelevant dissolution media (BDM) with the purpose of investigating which molecular structures gain most in solubility when dissolved under physiologically relevant conditions. The compounds were studied in four media (simulated intestinal fluid in fasted (FaSSIF pH 6.5) and fed state (FeSSIF pH 5.0), and their corresponding blank buffers (FaSSIFblk and FeSSIFblk)) at a temperature of 37 °C. The experimental results were used to analyze which molecular characteristics are of importance for the solubility in BDM and for in silico modeling using multivariate data analysis. It was revealed that a majority of the compounds exhibited a higher dissolution rate and higher solubility in the FaSSIF and FeSSIF than in their corresponding blank buffers. Compounds which were neutral or carried a positive charge were more soluble in FeSSIF than FaSSIF. The acidic compounds display...
TL;DR: Two previously unreported amorphous solid dispersions involving up to three components and containing voriconazole and telithromycin are analyzed using SSNMR experiments based on dipolar correlation, spin diffusion, and relaxation measurements to demonstrate the general applicability of the approach.
Abstract: Solid-state NMR (SSNMR) can provide detailed structural information about amorphous solid dispersions of pharmaceutical small molecules. In this study, the ability of SSNMR experiments based on dipolar correlation, spin diffusion, and relaxation measurements to characterize the structure of solid dispersions is explored. Observation of spin diffusion effects using the 2D 1H−13C cross-polarization heteronuclear correlation (CP-HETCOR) experiment is shown to be a useful probe of association between the amorphous drug and polymer that is capable of directly proving glass solution formation. Dispersions of acetaminophen and indomethacin in different polymers are examined using this approach, as well as 1H double-quantum correlation experiments to probe additional structural features. 1H−19F CP-HETCOR serves a similar role for fluorinated drug molecules such as diflunisal in dispersions, providing a rapid means to prove the formation of a glass solution. Phase separation is detected using 13C, 19F, and 23Na-de...
TL;DR: Evidence is provided that PAMAM-PEG-T7 can be applied as a potential tumor-targeting drug delivery system and in vitro antitumor effect was enhanced markedly and T7 may be a promising ligand for targeted drug delivery to the tumor.
Abstract: The purpose of this work was to evaluate the potential of HAIYPRH (T7) peptide as a ligand for constructing tumor-targeting drug delivery systems. T7 could target to transferrin-receptor (TfR) through a cavity on the surface of TfR and then transport into cells via endocytosis with the help of transferrin (Tf). In this study, T7-conjugated poly(ethylene glycol) (PEG)-modified polyamidoamine dendrimer (PAMAM) (PAMAM-PEG-T7) was successfully synthesized and further loaded with doxorubicin (DOX), formulating PAMAM-PEG-T7/DOX nanoparticles (NPs). In vitro, almost 100% of DOX was released during 2 h in pH 5.5, while only 55% of DOX was released over 48 h in pH 7.4. The cellular uptake of DOX could be significantly enhanced when treated with T7-modified NPs in the presence of Tf. Also, the in vitro antitumor effect was enhanced markedly. The IC(50) of PAMAM-PEG-T7/DOX NPs with Tf was 231.5 nM, while that of NPs without Tf was 676.7 nM. T7-modified NPs could significantly enhance DOX accumulation in the tumor by approximately 1.7-fold compared to that of unmodified ones and by approximately 5.3-fold compared to that of free DOX. For in vivo antitumor studies, tumor growth of mice treated with PAMAM-PEG-T7/DOX NPs was significantly inhibited compared to that of mice treated with PAMAM-PEG/DOX NPs and saline. The study provides evidence that PAMAM-PEG-T7 can be applied as a potential tumor-targeting drug delivery system. T7 may be a promising ligand for targeted drug delivery to the tumor.
TL;DR: This study evaluates a powerful two-pronged strategy for efficient treatment of atherosclerosis that includes nanomedical therapy of Atherosclerotic plaques and the application of noninvasive and clinically approved imaging techniques to monitor delivery and therapeutic responses.
Abstract: Atherosclerosis is an inflammatory disease causing great morbidity and mortality in the Western world. To increase the anti-inflammatory action and decrease adverse effects of glucocorticoids (PLP), a nanomedicinal liposomal formulation of this drug (L-PLP) was developed and intravenously applied at a dose of 15 mg/kg PLP to a rabbit model of atherosclerosis. Since atherosclerosis is a systemic disease, emerging imaging modalities for assessing atherosclerotic plaque are being developed. (18)F-Fluoro-deoxy-glucose positron emission tomography and dynamic contrast enhanced magnetic resonance imaging, methods commonly used in oncology, were applied to longitudinally assess therapeutic efficacy. Significant anti-inflammatory effects were observed as early as 2 days that lasted up to at least 7 days after administration of a single dose of L-PLP. No significant changes were found for the free PLP treated animals. These findings were corroborated by immunohistochemical analysis of macrophage density in the vessel wall. In conclusion, this study evaluates a powerful two-pronged strategy for efficient treatment of atherosclerosis that includes nanomedical therapy of atherosclerotic plaques and the application of noninvasive and clinically approved imaging techniques to monitor delivery and therapeutic responses. Importantly, we demonstrate unprecedented rapid anti-inflammatory effects in atherosclerotic lesions after the nanomedical therapy.
TL;DR: It is demonstrated that PTX/TPGS nanocrystals have significant advantages over Taxol in achieving better therapeutic effect in Taxol-resistant cancer cells both in vitro and in vivo, which was also confirmed by apoptosis assays.
Abstract: Here we described a paclitaxel (PTX) nanocrystal formulation using d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) as the sole excipient for overcoming multidrug resistance (MDR), a key challenge in current cancer therapy. To the best of our knowledge, it is the first report on PTX nanocrystals which can reverse MDR. TPGS serves as a surfactant to stabilize the nanocrystals and a P-gp inhibitor to reverse MDR. The size and morphology of the nanocrystals were studied by transmission electron microscopy, and the crystalline structure was determined by powder X-ray diffraction. An in vitro drug release profile showed that the nanocrystals exhibited sustained release kinetics compared to Taxol, which is the clinical paclitaxel formulation. The cytotoxicity and antitumor efficacy in xenograft models were also investigated. It is demonstrated that PTX/TPGS nanocrystals have significant advantages over Taxol in achieving better therapeutic effect in Taxol-resistant cancer cells both in vitro and in vivo, which was also confirmed by apoptosis assays. We envision that further development of this type of nanocrystal will provide a novel strategy for drug delivery and multidrug resistance treatment.
TL;DR: Results indicate that the poly(l-glutamic acid) dendrimers with OAS core are promising vectors for fabricating smart and targeting drug delivery systems.
Abstract: The functionalization of pH-sensitiveness and cellular targeting is a promising strategy to fabricate drug delivery systems with high efficiency, high selectivity and low toxicity. In this paper, a poly(l-glutamic acid) dendrimer based drug delivery system with both pH-sensitive and targeting functions is reported. Poly(l-glutamic acid) dendrimers with a polyhedral oligomeric silsesquioxane (POSS) nanocubic core were synthesized. Its globular morphology and compact structure with multiple peripheral functional groups made it suitable for drug delivery. The OAS-G3-Glu dendrimer was conjugated with doxorubicin via pH-sensitive hydrazine bonds and targeting moiety (biotin). The cellular internalization and antitumor effects of the conjugates was evaluated in vitro. Both DLS and TEM results indicated that the conjugates aggregated into nanoparticles with diameters around 50 nm. The release rates of doxorubicin at pH 5.0 were much faster than those at pH 7.0 due to the acid cleavage of the hydrazine bonds. The...
TL;DR: The Flory-Huggins interaction parameter was found to be a reasonably good indicator for predicting the phase stability of small molecule binary mixtures and can enable fast screening of the potential stabilizers needed to produce a stable amorphous binary mixture.
Abstract: The Flory-Huggins interaction parameter has been shown to be useful in predicting the thermodynamic miscibility of a polymer and a small molecule in a binary mixture. In the present paper, this concept was extended and evaluated to determine whether or not the Flory-Huggins interaction parameter can be applied to small molecule binary mixtures and if this parameter can predict the phase stability of such amorphous binary mixtures. This study was based on the assumption that a thermodynamically miscible binary system is stable and cannot crystallize, and that phase separation is essential before the individual components can crystallize. The stabilization of a binary system is thought to derive from molecular interactions between components in a solid dispersion, which are characterized by the Flory-Huggins interaction parameter. Based on DSC experiments, drug molecules (39) in the present study were classified into three different categories according to their crystallization tendency; i.e., highly crystallizing, moderately crystallizing and noncrystallizing compounds. The Flory-Huggins interaction parameter was systematically calculated for each drug pair. The validity of this approach was empirically verified by hot-stage polarized light microscopy. If both compounds in the pair belonged to the category of highly crystallizing compound, the Flory-Huggins interaction predicted an amorphous or crystalline phase with approximately 88% (23 out of 26) confidence. If one or both compounds of the pair were either moderately crystallizing or noncrystallizing compounds, the binary mixture remained in the amorphous phase during the cooling phase regardless of the interaction parameter. The Flory-Huggins interaction parameter was found to be a reasonably good indicator for predicting the phase stability of small molecule binary mixtures. The method described can enable fast screening of the potential stabilizers needed to produce a stable amorphous binary mixture.
TL;DR: The remarkable difference between thermodynamic solubility/miscibility and kinetic miscibility implied that naproxen was highly supersaturated in the PVP solid dispersions and only stabilized kinetically.
Abstract: The objective of the present study was to determine the solid state solubility and miscibility of naproxen in poly(vinylpyrrolidone) (PVP) and the mutual interaction using the standard thermodynamic models and thermal analysis. Solid dispersions were prepared by spray drying several compositions of naproxen and PVP with different molecular weights, viz., PVP K 12, PVP K 25 and PVP K 90, and analyzed using modulated differential scanning calorimetry (mDSC). The kinetic miscibility limit in terms of a single mixed phase glass transition temperature was found to be relatively similar for the dispersions containing PVP with different chain lengths (≥50% w/w drug in PVP). But the systems with different PVP followed diverse patterns of composition dependent mixed phase glass transition temperature as well as the degree of plasticization by water. The crystalline solid solubility values of naproxen in PVP estimated by using its solubility data in n-methylpyrrolidone, a low molecular weight analogue of PVP, were ...
TL;DR: It is suggested that oral administration of PLGA nanoparticles encapsulating curcumin enhances the effects ofCurcumin therapy in CF mice, as compared to delivery of nonencapsulated cur cumin.
Abstract: Cystic fibrosis (CF) is a common life threatening genetic disease (incidence: approximately 1 in 2500 live births) CF is caused by mutations in CFTR, a chloride channel involved in epithelial secretion of fluid and electrolytes The most common mutation entails the deletion of a phenylalanine in position 508 that causes protein misfolding and abnormal CFTR processing The DeltaF508 mutation accounts for approximately 70% of all CF alleles, and about 90% of CF patients carry at least one copy of DeltaF508 CFTR Curcumin, a natural constituent of Curcuma longa (turmeric spice), is a nontoxic low-affinity SERCA (sarco (endo)plasmic reticulum calcium ATPase) pump inhibitor thought to permit DeltaF508 CFTR escape from the ER The compound has been shown to be capable of correcting the defect in cell lines and mice expressing DeltaF508 CFTR In this work, poly lactic-co-glycolic acid (PLGA) nanoparticles encapsulating curcumin were synthesized and used to treat two different CF mouse strains in an effort to correct the defects associated with CF by improving bioavailability of the compound, which has previously been a challenge in treatment with curcumin Our results suggest that oral administration of PLGA nanoparticles encapsulating curcumin enhances the effects of curcumin therapy in CF mice, as compared to delivery of nonencapsulated curcumin
TL;DR: Results suggest that encapsulation of TLR ligands within Ac-DEX microparticles results in increased immunostimulation and potentially better protection from disease when used in conjunction with vaccine formulations.
Abstract: Toll-like receptor (TLR) agonists induce potent innate immune responses and can be used in the development of novel vaccine adjuvants. However, access to TLRs can be challenging as exemplified by TLR 7, which is located intracellularly in endosomal compartments. To increase recognition and subsequent stimulatory effects of TLR 7, imiquimod was encapsulated in acetalated dextran (Ac-DEX) microparticles. Ac-DEX, a water-insoluble and biocompatible polymer, is relatively stable at pH 7.4, but degrades rapidly under acidic conditions, such as those found in lysosomal vesicles. To determine the immunostimulatory capacity of encapsulated imiquimod, we compared the efficacy of free versus encapsulated imiquimod in activating RAW 264.7 macrophages, MH-S macrophages, and bone marrow derived dendritic cells. Encapsulated imiquimod significantly increased IL-1β, IL-6, and TNF-α cytokine expression in macrophages relative to the free drug. Furthermore, significant increases were observed in classic macrophage activat...
TL;DR: The pSi carrier facilitates accelerated immediate release of IMC and enhanced oral delivery performance in comparison with crystalline indomethacin and Indocid i.e. a 4-times reduction on T(max), a 200% increase on C(max) and a significant increase in bioavailability.
Abstract: Surface functionalized mesoporous silicon (pSi) microparticles are reported as a solid dispersion carrier for improving dissolution and enhancing the orally administered pharmacokinetics (fasted ra...
TL;DR: A novel antitumor agent loaded drug delivery system, lactoferrin-conjugated biodegradable polymersome holding doxorubicin and tetrandrine (Lf-PO-Dox/Tet), integrating both BBB and glioma-targeting moiety and MDR inhibitor, demonstrated the strongest cytotoxicity against C6 gliomas cells and the greatest uptake index by C6 cells.
Abstract: The blood-brain barrier (BBB) and multidrug resistance (MDR) are the main causes for poor prognosis of glioma patients after chemotherapy. To explore the way for settling this problem, in this study, a novel antitumor agent loaded drug delivery system, lactoferrin-conjugated biodegradable polymersome holding doxorubicin and tetrandrine (Lf-PO-Dox/Tet), integrating both BBB and glioma-targeting moiety and MDR inhibitor, was designed and its chemotherapy for glioma rats was evaluated. Biodegradable polymersome (PO) encapsulating both doxorubicin (Dox) and tetrandrine (Tet) was prepared by the thin-film hydration method (PO-Dox/Tet) and then conjugated with lactoferrin (Lf) to yield Lf-PO-Dox/Tet with an average diameter around 220 nm and surface Lf molecule number per polymersome around 40. Compared with PO-DOX, PO-Dox/Tet, and Lf-PO-Dox, Lf-PO-Dox/Tet demonstrated the strongest cytotoxicity against C6 glioma cells and the greatest uptake index by C6 cells. In vivo imaging analysis indicated that Lf-PO labeled with a near-infrared dye could enter the brain and accumulate at the tumor site. Pharmacokinetics and tissue distribution results also showed that Lf-PO-Dox/Tet accumulated more in the right hemisphere than other groups of polymersomes. Pharmacodynamics results revealed that tumor volume of the Lf-PO-Dox/Tet group was significantly smaller than that of other therapeutic groups, and the median survival time of Lf-PO-Dox/Tet group was longer than that of Lf-PO-Dox group and significantly longer than those of the other three therapeutic groups. These results suggested that Lf-PO-Dox/Tet could have therapeutic potential for gliomas.
TL;DR: Delivering lidocaine intranasally may provide an effective anesthetic technique for a noninvasive maxillary nerve block and could be used to target vaccinations and treat disorders with fewer side effects such as tooth pain, TMJ disorder, trigeminal neuralgia, headache, and brain diseases.
Abstract: Intranasal delivery has been shown to non-invasively deliver drugs from the nose to the brain in minutes along the olfactory and trigeminal nerve pathways, bypassing the blood-brain barrier. However, no one has investigated whether nasally applied drugs target orofacial structures, despite high concentrations observed in the trigeminal nerve innervating these tissues. Following intranasal administration of lidocaine to rats, trigeminally-innervated structures (teeth, temporomandibular joint (TMJ), and masseter muscle) were found to have up to 20-fold higher tissue concentrations of lidocaine than the brain and blood as measured by ELISA. This concentration difference could allow intranasally administered therapeutics to treat disorders of orofacial structures (i.e. teeth, TMJ, and masseter muscle) without causing unwanted side effects in the brain and the rest of the body. In this study, an intranasally administered infrared dye reached the brain within 10 minutes. Distribution of dye is consistent with dye entering the trigeminal nerve after intranasal administration through three regions with high drug concentrations in the nasal cavity: the middle concha, the maxillary sinus, and the choana. In humans the trigeminal nerve passes through the maxillary sinus to innervate the maxillary teeth. Delivering lidocaine intranasally may provide an effective anesthetic technique for a non-invasive maxillary nerve block. Intranasal delivery could be used to target vaccinations and treat disorders with fewer side effects such as tooth pain, TMJ disorder, trigeminal neuralgia, headache, and brain diseases.
TL;DR: This work investigates how two types of surface modification, acetylation and PEGylation, affect the DNA binding characteristics, the cytotoxicity and the in vitro transfection efficiency of generation 4 and 5 PAMAM dendrimers.
Abstract: Poly(amidoamine) (PAMAM) dendrimers are promising multipotent gene delivery vectors, providing favorable DNA condensation properties also in combination with the possibility of conjugation of different targeting ligands to their surface. They have been used for transfection both in vitro and in vivo, but their application is currently somewhat limited due to inherent cytotoxicity. In this work we investigate how two types of surface modification, acetylation and PEGylation, affect the DNA binding characteristics, the cytotoxicity and the in vitro transfection efficiency of generation 4 and 5 PAMAM dendrimers. Particularly, we address how the morphology of DNA-dendrimer complexes, formed under low salt conditions, changes upon dilution in cell growth medium, an event that inevitably occurs before the complexes reach the cell surface in any transfection experiment. We find that acetylation and PEGylation essentially eliminates the inherent dendrimer cytotoxicity. However, the transfection efficiency of the modified dendrimers is lower than that of the corresponding unmodified dendrimers, which can be rationally understood by our observations that DNA is less condensed when complexed with these modified dendrimers. Although small DNA-dendrimer particles are formed, the availability for ethidium intercalation and nuclease degradation is significantly higher in the modified DNA-dendrimer complexes than in unmodified ones. Dilution in cell growth medium has a drastic effect on these electrostatically assembled complexes, resulting in increase in size and DNA availability. Our results strongly add to the notion that it is of importance to perform a biophysical characterization under conditions as close to the transfection situation as possible, to enable conclusions regarding structure-activity relations of gene delivery vectors.
TL;DR: The developed HuCC49ΔCH2-SPIO nanotheranostics provides an integrated platform for cancer cell imaging, targeted anticancer drug delivery and pH-dependently drug release.
Abstract: Studies were conducted to develop antibody- and fluorescence-labeled superparamagnetic iron oxide nanoparticle (SPIO) nanotheranostics for magnetic resonance imaging (MRI) and fluorescence imaging of cancer cells and pH-dependent intracellular drug release. SPIO nanoparticles (10 nm) were coated with amphiphilic polymers and PEGylated. The antibody HuCC49ΔCH2 and fluorescent dye 5-FAM were conjugated to the PEG of iron oxide nanoparticles (IONPs). Anticancer drugs doxorubicin (Dox), azido-doxorubicin (Adox), MI-219, and 17-DMAG containing primary amine, azide, secondary amine, and tertiary amine, respectively, were encapsulated into IONPs. The encapsulation efficiency and drug release at various pHs were determined using LC-MS/MS. The cancer targeting and imaging were monitored using MRI and fluorescent microscopy in a colon cancer cell line (LS174T). The pH-dependent drug release, intracellular distribution, and cytotoxicity were evaluated using microscopy and MTS assay. The PEGylation of SPIO and conjugation with antibody and 5-FAM increased SPIO size from 18 to 44 nm. Fluorescent imaging, magnetic resonance imaging (MRI) and Prussian blue staining demonstrated that HuCC49ΔCH2-SPIO increased cancer cell targeting. HuCC49ΔCH2-SPIO nanotheranostics decreased the T(2) values in MRI of LS174T cells from 117.3 ± 1.8 ms to 55.5 ± 2.6 ms. The loading capacities of Dox, Adox, MI-219, and 17-DMAG were 3.16 ± 0.77%, 6.04 ± 0.61%, 2.22 ± 0.42%, and 0.09 ± 0.07%, respectively. Dox, MI-219 and 17-DMAG showed pH-dependent release while Adox did not. Fluorescent imaging demonstrated the accumulation of HuCC49ΔCH2-SPIO nanotheranostics in endosomes/lysosomes. The encapsulated Dox was released in acidic lysosomes and diffused into cytosol and nuclei. In contrast, the encapsulated Adox only showed limited release in endosomes/lysosomes. HuCC49ΔCH2-SPIO nanotheranostics target-delivered more Dox to LS174T cells than nonspecific IgG-SPIO and resulted in a lower IC(50) (1.44 μM vs 0.44 μM). The developed HuCC49ΔCH2-SPIO nanotheranostics provides an integrated platform for cancer cell imaging, targeted anticancer drug delivery and pH-dependently drug release.
TL;DR: A novel strategy for formulation of nanosized, echogenic lipid bubbles by incorporating the surfactant Pluronic, a triblock copolymer of ethylene oxide copropylene oxide coethylene oxide into the formulation is presented and it is concluded that pluronic is effective in lipid bubble size control.
Abstract: The advent of microbubble contrast agents has enhanced the capabilities of ultrasound as a medical imaging modality and stimulated innovative strategies for ultrasound-mediated drug and gene delivery. While the utilization of microbubbles as carrier vehicles has shown encouraging results in cancer therapy, their applicability has been limited by a large size which typically confines them to the vasculature. To enhance their multifunctional contrast and delivery capacity, it is critical to reduce bubble size to the nanometer range without reducing echogenicity. In this work, we present a novel strategy for formulation of nanosized, echogenic lipid bubbles by incorporating the surfactant Pluronic, a triblock copolymer of ethylene oxide copropylene oxide coethylene oxide into the formulation. Five Pluronics (L31, L61, L81, L64 and P85) with a range of molecular weights (Mw: 1100 to 4600 Da) were incorporated into the lipid shell either before or after lipid film hydration and before addition of perfluorocarb...