Size-tunable and biodegradable thrombin-functionalized carboxymethyl chitin microspheres for endovascular embolization.

As a minimally invasive method, endovascular embolization has been an effective strategy for controlling bleeding and tumor treatment. Herein, carboxymethyl chitin embolic microspheres were prepared with the aqueous two-phase carboxymethyl chitin/polyethylene glycol system without using any crosslinking agents and thrombin-functionalized embolic microsphere named as Thr@CMCHm-30 was made after covalent introduction of thrombin. The size of the microspheres can be adjusted from 5 to 500 µm. The data of in vitro and in vivo tests indicated that these microspheres possessed good degradability and biocompatibility. Meanwhile, Thr@CMCHm-30 can significantly promote blood clotting and enhance the strength of the blood clots. More importantly, Thr@CMCHm-30 displayed better embolization effect than that of the commercial available Gelfoam Alicon® and polyvinyl alcohol-based embolic microspheres CalliSpheres® in rat femoral vein and rabbit ear artery embolization models. Therefore the size-tunable and biodegradable thrombin-functionalized carboxymethyl chitin microspheres Thr@CMCHm-30 possess great potential for effective hemostasis and endovascular embolization.

Quartz crystal microbalance sensor based on 11-mercaptoundecanoic acid self-assembly and amidated nano-titanium film for selective and ultrafast detection of phosphoproteins in food.

A novel quartz crystal microbalance (QCM) sensor for trace-phosphoprotein ultrafast detection was constructed based on the bridge interactions between the NH2-TiO2 sites enriched on Au-electrode and phosphate groups. Herein, 11-mercaptoundecanoic acid (MUA) modified by Au-S bond acted as carrier for immobilizing NH2-TiO2. Functionalized NH2-TiO2 to absorb phosphoproteins. Under the optimal conditions, the proposed sensor showed a linear frequency shift to the concentration of α-casein ranging from 1.0 × 10-3 to 1.0 mg mL-1 with a low detection limit of 5.3 × 10-6 mg mL-1 (S/N = 3), and the limit of quantitation was 0.001 mg mL-1. Compared with traditional Ti4+-IMAC/MOAC-system, the analysis process of NH2-TiO2/MUA/AuE-QCM sensor was simpler and faster which could complete within 5 min. Additionally, the constructed biosensor was successfully used for the non-fat milk and chicken egg white. This proposed sensor presents a great prospective strategy for the evaluation of the nutrition in different foods.

An insect acetylcholinesterase biosensor utilizing WO3/g-C3N4 nanocomposite modified pencil graphite electrode for phosmet detection in stored grains.

This study was undertaken to assess the potential of Tribolium castaneum (Red flour beetle) acetylcholinesterase (Tc-AChE) based electrochemical biosensor integrating WO3/g-C3N4 nanocomposite modified Pencil graphite electrode to detect an organophosphate insecticide, Phosmet. The WO3/g-C3N4 nanocomposite provides a non-toxic, biocompatible surface for binding the enzyme on the electrode surface, attributed to its large surface area, high conductivity, and low ohmic resistance. The proposed biosensor shows a very good analytical performance with LOD 3.6 nM for Phosmet and effectively determined Phosmet in wheat with a 99% recovery rate. Furthermore, molecular docking deciphers the binding interactions of Phosmet with Tc-AChE using a modified AutoDock LGA algorithm and an AMBER03 force field in YASARA. The kinetic parameters strongly suggest the high potency of inhibitor with the enzyme. This study presents an adaptable, rapid, and straightforward approach that opens ways towards real progress in developing commercial biosensors for pesticide detection.

Targeted imaging of breast cancer cells using two different kinds of aptamers -functionalized nanoparticles.

Breast cancer which is the most commonly diagnosed cancer among women; have been known as a serious threat for health and life around the world. So development of an approach for early-stage diagnosis of breast cancer is vital. In this study, we designed a double aptamer-nanoparticle conjugates-based (DANP) complex for specific detection and visualization of MCF-7 cells using Mucin 1 (MUC 1) aptamer-conjugated gold nanoparticles (MUC1 apt - GNPs) and adenosine triphosphate (ATP) aptamer-conjugated CdTe quantum dots (ATP apt-QDs). The ATP apt-QDs was attached onto MUC1 apt - GNPs surface through Van der Waals forces and electrostatic interactions between ATP aptamer and GNPs leading to the formation of DANP complex. Atomic force microscopy asserted DANP complex formation. The imaging process was based on the recognition of MUC1 protein on the surface of MCF-7 cells by MUC1 aptamer and specific internalization of DANP complex into target cells (MCF-7). Existence of abundant amounts of ATP in lysosome led to release of ATP apt-QDs from the MUC1 apt-GNPs surface resulting in strong fluorescence emission. The flow cytometry analysis and fluorescence microscopy confirmed significant internalization of DANP complex into MCF-7 cells (target) in comparison with CHO cells (non-target). Based on the obtained results, the DANP complex possesses high potency for efficient detection and monitoring of breast cancer cells (MCF-7).

Development of a sensitive monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for analysing nobiletin in citrus and herb samples.

Nobiletin, a polymethoxyflavone mainly found in citrus fruits, have been reported to exhibit various beneficial biological activities for human health. It is an important bioactive compound in traditional Chinese medicine, Pericarpium Citri Reticulatae and Fructus Aurantii. To detect the contents of nobiletin in citrus and herb samples, we developed an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on monoclonal antibodies. It possessed a median inhibition concentration (IC50) of 2.43 ±â€¯0.19 ng/mL and a working range of 0.52-12.3 ng/mL. The assay exhibited the average recoveries of 72.5-85.3% in citrus peel, pulp and juice samples. Moreover, eleven citrus cultivars samples and four herb samples were also detected by the icELISA. The nobiletin content varied in different citrus cultivars samples and herb samples, which were confirmed by the ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS). These results indicated that the developed immunoassay was suitable for detecting nobiletin in citrus and herb samples.

Smart nanocarrier based on PEGylated hyaluronic acid for deacetyl mycoepoxydience: High stability with enhanced bioavailability and efficiency.

Deacetyl mycoepoxydience (DM) nanocrystals core were stabilized by the folate modified distearoylphosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG2000-FA) as the active-targeting stabilizer and D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) as the reversion of multidrug resistance stabilizer, respectively. The DM nanocrystals was acted as the core and shelled by the polyethylene glycol-hyaluronic acid (PEG-HA). The optimal core-shell system demonstrated superior stability at 4 °C for 6 weeks by the stability study and higher dissolution velocity. Cytotoxicity in vitro and cell proliferation inhibition was evaluated by MCF-7 cells line. Furthermore, the core-shell nanocrystals revealed a concentration- and time-dependent cytotoxicity activity and enhanced the cell proliferation inhibition. Pharmacokinetic studies in rabbits showed core-shelled DM nanocrystals significantly increased AUC and t1/2 and reduced CLz compared to the DM solution for intravenous delivery. Results indicated that core-shell nanocrystals nanogel was successfully established with higher stability and the bioavailability of DM with higher safety was improved.

Sensitivity enhancement for mycotoxin determination by optical waveguide lightmode spectroscopy using gold nanoparticles of different size and origin.

Mycotoxins, present in a wide range of food and feed commodities, are toxic secondary metabolites produced by a number of different fungi. Certain mycotoxins do not readily degrade at high temperatures, therefore are resistant to food processing, and consequently are present in the human and animal food supply. Optical waveguide lightmode spectroscopy (OWLS) was applied for the detection of aflatoxin B1, in a competitive immunoassay format, to compare the analytical sensitivity achieved with an immunosensor design allowing signal enhancement by increasing the sensor surface through immobilization of gold nanoparticles (AuNPs) of different size and origin (obtained by chemical or biotechnological synthesis). The effects of AuNPs median size, the methods of sensitization and the biochemical parameters on immunosensor performace were examined. After optimization of the sensitized sensor surface, an immunosensing method was developed for the analysis of aflatoxin in paprika matrix and the results were compared with HPLC reference measurements.

Development and evaluation of long-circulating nanoparticles loaded with betulinic acid for improved anti-tumor efficacy.

The clinical application of betulinic acid (BA), a natural pentacyclic triterpenoid with promising antitumor activity, is hampered due to its extremely poor water solubility and relatively short half-life in the systemic circulation. In order to address these issues, herein, we developed betulinic acid loaded polylactide-co-glycolide- monomethoxy polyethylene glycol nanoparticles (PLGA-mPEG NPs). The PLGA-mPEG co-polymer was synthesized and characterized using NMR and FT-IR. BA loaded PLGA-mPEG NPs were prepared by an emulsion solvent evaporation method. The developed nanoparticles had a desirable particle size (∼147nm) and exhibited uniform spherical shape under transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The PLGA-mPEG NPs were able to decrease the uptake by macrophages (i.e. J774A.1 and Raw 264.7 cells) as compared to PLGA nanoparticles. In vitro cytotoxicity in MCF7 and PANC-1 cells demonstrated enhanced cytotoxicity of BA loaded PLGA-mPEG NPs as compared to free BA. The cellular uptake study in both the cell lines demonstrated time dependent uptake behavior. The enhanced cytotoxicity of BA NPs was also supported by increased cellular apoptosis, mitochondrial membrane potential loss, generation of high reactive oxygen species (ROS) and cell cycle arrest. Further, intravenous pharmacokinetics study revealed that BA loaded PLGA-mPEG NPs could prolong the circulation of BA and remarkably enhance half-life by ∼7.21 folds. Consequently, in vivo studies in Ehrlich tumor (solid) model following intravenous administration demonstrated superior antitumor efficacy of BA NPs as compared to native BA. Moreover, BA NPs treated Ehrlich tumor mice demonstrated no biochemical, hematological and histological toxicities. These findings collectively indicated that the BA loaded PLGA-mPEG NPs might serve as a promising nanocarrier for improved therapeutic efficacy of betulinic acid.

Development and mechanistic insight into enhanced cytotoxic potential of hyaluronic acid conjugated nanoparticles in CD44 overexpressing cancer cells.

The overexpression of CD44 in cancer cells reroutes number of oncogenic pathways including the central Pi3K/Akt/NF-kB pathway leading to cancer progression and malignancy. Herein, we developed hyaluronic acid-modified poly(dl-lactic-co-glycolic acid)-poly (ethylene glycol) nanoparticles (PLGA-PEG-HA NPs) for targeted delivery of TTQ (thio-tetrazolyl analog of a clinical candidate, IC87114) to CD44 overexpressing cancer cells. The PLGA-PEG co-polymer was synthesized and characterized by NMR and FTIR. The co-polymer based nanoparticles were prepared by solvent evaporation method and hyaluronic acid (HA) was conjugated on to the nanoparticle surface via EDC/NHS chemistry. The PLGA-PEG-HA NPs had a desirable particle size (<200nm) with reduced polydispersibility and exhibited spherical shape under atomic force microscope (AFM). In vitro cytotoxicity and cellular uptake studies demonstrated higher cytotoxicity and enhanced intracellular accumulation of PLGA-PEG-HA NPs compared to PLGA-PEG NPs in high CD44 expressing MiaPaca-2 cells compared to MDA-MB-231 and MCF7 cells. At the molecular level, the PLGA-PEG-HA NPs were found to be inducing premature senescence with increase in senescence associated ß-galactosidase activity and senescence specific marker p21 expression through modulation of Pi3K/Akt/NF-kB signaling pathway in MiaPaca-2 cells. These findings collectively indicated that HA-modified nanoparticles might serve as a promising nanocarrier for site-specific drug delivery, and can be explored further to increase the therapeutic efficacy of anticancer drugs via targeting to CD44 over-expressing cancer cells.

Thiomers: Impact of in situ cross-linkers on mucoadhesive properties.

The aim of this study was to evaluate the impact of in situ cross-linkers on the gelling and mucoadhesive properties of thiomers. Polycarbophil-cysteine conjugate (PCP-cys) was synthesized by covalent attachment of l-cysteine to polycarbophil via amide bond formation mediated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) and N-hydroxysuccinimide (NHS) whereas in situ cross-linkers (PAA-cys-MNA) were synthesized by the same bond formation between poly(acrylic acid) (PAA) of 2.1-, 6-, and 15kDa and 2-((2-amino-2-carboxyethyl)disulfanyl)nicotinic acid (cys-MNA) used as ligand. The in situ cross-linking properties were studied via rheological measurements of dynamic viscosity of mixtures of PCP-cys and PAA-cys-MNA with purified porcine intestinal mucus and via rotating cylinder method. The diffusion of polymers in purified porcine intestinal mucus was studied via rotating tube technique. The results showed that in situ cross-linkers (PAA 2.1-, 6-, 15kDa) increase the dynamic viscosity of PCP-cys/mucus mixtures by 5.1-, 5.6-, and 3.5-fold. Combinations of 10% of in situ cross-linkers PAA 2.1-, 6- or 15kDa and 90% PCP-cys increased the adhesion time 1.1-, 2.0- and 4.9-fold, respectively, compared to PCP-cys alone. Diffusion study showed that low molecular mass PAAs highly penetrate into the mucus gel layer due to their high polymer chain mobility compared to PCP-cys. The results provide evidence for the potential of in situ cross-linking agents as gelling and mucoadhesion enhancers.

Metal-organic framework preparation using magnetic graphene oxide-ß-cyclodextrin for neonicotinoid pesticide adsorption and removal.

A novel magnetic copper-based metal-organic framework (M-MOF) was prepared using a Fe4O3-graphene oxide (GO)-ß-cyclodextrin (ß-CD) nanocomposite as the magnetic core and support, and used for adsorption and removal of neonicotinoid insecticide pollutants from aqueous solution. M-MOF characterization suggested that 1Fe4O3-GO-ß-CD consisted of a thin single layer with anchored Fe3O4. The M-MOF was coated on the Fe4O3-GO-ß-CD surface. The M-MOF had a large Brunauer-Emmett-Teller surface area (250.33m2g-1) and high super-paramagnetism with saturation magnetization of 10.47emug-1. Adsorption model analysis showed that the equilibrium data for thiacloprid fitted Langmuir monolayer adsorption and the other insecticides tested showed Freundlich bimolecular layer adsorption. The results show that M-MOF is a promising hybrid adsorbent for rapid removal of neonicotinoid insecticide pollutants from environmental waters.

Fine-tuned PEGylation of chitosan to maintain optimal siRNA-nanoplex bioactivity.

Polyethylene glycol (PEG) is a widely used modification for drug delivery systems. It reduces undesired interaction with biological components, aggregation of complexes and serves as a hydrophilic linker of ligands for targeted drug delivery. However, PEGylation can also lead to undesired changes in physicochemical characteristics of chitosan/siRNA nanoplexes and hamper gene silencing. To address this conflicting issue, PEG-chitosan copolymers were synthesized with stepwise increasing degrees of PEG substitution (1.5% to 8.0%). Subsequently formed PEG-chitosan/siRNA nanoplexes were characterized physicochemically and biologically. The results showed that small ratios of chitosan PEGylation did not affect nanoplex stability and density. However, higher PEGylation ratios reduced nanoplex size and charge, as well as cell uptake and final siRNA knockdown efficiency. Therefore, we recommend fine-tuning of PEGylation ratios to generate PEG-chitosan/siRNA delivery systems with maximum bioactivity. The degree of PEGylation for chitosan/siRNA nanoplexes should be kept low in order to maintain optimal nanoplex efficiency.

Long-circulatory nanoparticles for gemcitabine delivery: Development and investigation of pharmacokinetics and in-vivo anticancer efficacy.

The anticancer potential of gemcitabine, a nucleoside analog, is compromised due to the enzymatic degradation into inactive form leading to the short half-life in systemic circulation. Novel delivery strategies are required to improve therapeutic efficacy of this potential drug. Monomethoxy polyethylene glycol amine-polylactide-co-glycolide (mPEG-PLGA) co-polymer was synthesized and characterized by FTIR and (1)H NMR. Gemcitabine loaded mPEG-PLGA nanoparticles (NPs) were developed and investigated for pharmacokinetic profile and in vivo anticancer activity. The mPEG-PLGA NPs (size: 267±10nm, zeta potential: -17.5±0.2mV) exhibited sustained drug release profile and were found to be compatible with blood. The mPEG-PLGA NPs were able to evade the uptake by macrophages (i.e. THP-1 and J774A) by reducing the adsorption of proteins on the surface of NPs. The enhanced cellular uptake and cell cytotoxicity was observed by mPEG-PLGA NPs in MiaPaCa-2 and MCF-7 cells. The half-life of gemcitabine in mPEG-PLGA NPs was remarkably enhanced (19 folds) than native gemcitabine. Further, the pharmacokinetic modulation of gemcitabine using mPEG-PLGA-NPs was translated in improved anticancer efficacy as compared to native gemcitabine in Ehrlich ascites bearing Balb-c mice. The results demonstrated the potential of long-circulatory nanoparticles in improving the pharmacokinetic profile and in-turn the anticancer efficacy of gemcitabine.

Peptide-conjugated hyaluronic acid surface for the culture of human induced pluripotent stem cells under defined conditions.

Hyaluronic acid (HA) has been cross-linked to form hydrogel for potential applications in the self-renewal and differentiation of human pluripotent stem cells (hPSCs) for years. However, HA hydrogel with improved residence time and mechanical integrity that allows the survival of hPSCs under defined conditions is still much needed for clinical applications. In this study, HA was modified with methacrylate functional groups (MeHA) and cross-linked by photo-crosslinking method. After subsequent conjugation with adhesive peptide, these MeHA surfaces demonstrated performance in facilitating human induced pluripotent stem cells (hiPSCs) proliferation, and good pluripotency maintenance of hiPSCs under defined conditions. Moreover, MeHA films on glass-slides exhibited long residence time and mechanical stability throughout hiPSC culture. Our photo-crosslinkable MeHA possesses great value in accelerating the application of HA hydrogel in hiPSCs proliferation and differentiation with the conjugation of adhesive peptides.

pH-sensitive polymeric micelles formed by doxorubicin conjugated prodrugs for co-delivery of doxorubicin and paclitaxel.

A doxorubicin conjugated prodrug incorporated acid-sensitive linkage between drug and Pluronic F127-chitosan (F127-CS) polymer was successfully synthesized. Subsequently a pH-sensitive polymeric micelle system was designed based on the conjugated prodrugs (F127-CS-DOX) to co-deliver doxorubicin and paclitaxel. Paclitaxel (PTX) was physically entrapped in the hydrophobic inner core of the micelles simultaneously. The structures of conjugates were analyzed by means of (1)H NMR and UV-vis spectrum. Size distribution and morphology of the micelles were observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results indicated that obtained micelles had good dispersity and the diameter was between 56.3 and 403.4 nm. The loading of PTX into the micelle increased with higher DOX content. DOX and PTX release from polymeric micelles followed an acid-triggered manner. Furthermore, in vivo pharmacokinetic study also showed that the area under the plasma concentration time curve (AUC0-∞) values of PTX and DOX for PTX-loaded F127-CS-DOX micelles in rats were 3.97 and 4.38-fold higher than those for PTX plus DOX solution. These results suggested the PTX-loaded F127-CS-DOX micelles would be a promising carrier for co-delivering DOX and PTX.

Polymeric micelles of amphiphilic graft copolymer of α-tocopherol succinate-g-carboxymethyl chitosan for tamoxifen delivery: Synthesis, characterization and in vivo pharmacokinetic study.

Novel amphiphilic graft copolymers were prepared from low molecular weight carboxymethyl chitosan (LMW Cmc) and α-tocopherol succinate (TS) via an amidation reaction and confirmed by (1)H NMR and IR spectroscopy. These graft copolymers are self-assembled to nanosized core-shell-structural micelles in an aqueous milieu. The critical micelle concentration (CMC) decreased with an increasing substitution of TS on LMW Cmc, which ranged from 7.94×10(-8) to 1.58×10(-6)g/mL. Cmc-TS4.5 (Cmc-TS with a charged molar ratio of TS to glucosamine units of Cmc∼4.5) was shown maximum TMX loading up to 8.08±0.98%. Both blank and TMX-loaded PM's of Cmc-TS4.5 exhibit spherical shape with particle size below 200nm. An in vitro release study in simulated gastric and intestinal fluid demonstrated that TMX release from TMX-PM4.5 (TMX-PMs prepared with amphiphilic polymer Cmc-TS4.5, and the weight ratio of Cmc-TS4.5 to TMX was 8:1) was slow and pH dependent. In vivo oral absorption study revealed Cmc-TS4.5 based PM's permeated the epithelial barrier via the paracellular route without causing any intestinal damage. In vivo toxicity study demonstrated the safety of PM's after oral administration. Compared to tamoxifen control, TMX-PM4.5 dosed to fasted female Sprague Dawley rats showed a 1.9 fold increase in AUC0-72h. Thus, the results suggested that Cmc-TS micelles are a promising carrier for TMX delivery.

The targeted delivery of doxorubicin with transferrin-conjugated block copolypeptide vesicles.

We previously investigated the intracellular trafficking properties of our novel poly(l-glutamate)60-b-poly(l-leucine)20 (E60L20) vesicles (EL vesicles) conjugated to transferrin (Tf). In this study, we expand upon our previous work by investigating the drug encapsulation, release, and efficacy properties of our novel EL vesicles for the first time. After polyethylene glycol (PEG) was conjugated to the vesicles for steric stability, doxorubicin (DOX) was successfully encapsulated in the vesicles using a modified pH-ammonium sulfate gradient method. Tf was subsequently conjugated to the vesicles to provide active targeting to cancer cells and a mode of internalization into the cells. These Tf-conjugated, DOX-loaded, PEGylated EL (Tf-DPEL) vesicles exhibited colloidal stability and were within the allowable size range for passive and active targeting. A mathematical model was then derived to predict drug release from the Tf-DPEL vesicles by considering diffusive and convective mass transfer of DOX. Our mathematical model reasonably predicted our experimentally measured release profile with no fitted parameters, suggesting that the model could be used in the future to manipulate drug carrier properties to alter drug release profiles. Finally, an in vitro cytotoxicity assay was used to demonstrate that the Tf-DPEL vesicles exhibited enhanced drug carrier efficacy in comparison to its non-targeted counterpart.

Development and evaluation of folate functionalized albumin nanoparticles for targeted delivery of gemcitabine.

Gemcitabine is one of the most potent anticancer agents acting on a wide range of solid tumors, however, its use is limited by short half life and high dose leading to serious side effects. The present investigation describes the development and characterization of folate functionalized gemcitabine loaded bovine serum albumin nanoparticles (Fa-Gem-BSANPs). The nanoparticles were prepared by desolvation cross-linking technique and characterized for various parameters including morphology, particle size, zeta potential, drug loading and release profile. The particle size of Gem-BSANPs and Fa-Gem-BSANPs was found to be 159.1±5.29 and 208.7±1.80 nm, respectively. DSC and XRD analysis indicated amorphous nature of the drug within the particles. The encapsulated gemcitabine exhibited less hemolytic properties as compared to native drug. The anticancer activity of Fa-Gem-BSANPs was evaluated in folate receptor over expressing cell lines (Ovcar-5 and MCF-7) and folate receptor deficient cell line (MIAPaCa-2). The Fa-Gem-BSANPs showed superior anticancer activity as compared to Gem-BSANPs in Ovcar-5 and MCF-7 cells while no significant difference in cytotoxicity was found with MIAPaCa-2 cells. Confocal microscopy indicated facilitated intracellular uptake of Fa-Gem-BSANPs in MCF-7, which in turn result in a higher potential for apoptosis. Further, Fa-Gem-BSANPs exhibited improved anti-tumor activity in Ehrlich solid tumor model in mice. In conclusion, our study indicates that folate functionalized nanoparticles confer enhance cellular uptake and cytotoxicity for gemcitabine.

A micelle-like structure of poloxamer-methotrexate conjugates as nanocarrier for methotrexate delivery.

The purpose of this study was to develop a novel featured and flexible methotrexate (MTX) formulation, in which MTX was physically entrapped and chemically conjugated in the same drug delivery system. A series of poloxamer-MTX (p-MTX) conjugates was synthesized, wherein MTX was grafted to poloxamer through an ester bond. p-MTX conjugates could self-assemble into micelle-like structures in aqueous environment and the MTX end was in the inner-core of micelles. Moreover, free MTX could be physically entrapped into p-MTX micelles hydrophobic core region to increase the total drug loading. Importantly, the resulting MTX-loaded p-MTX micelles showed a biphasic release of MTX, with a relative fast release of the entrapped MTX (about 6-7h) followed by a sustained release of the conjugated MTX. The pharmacokinetics study showed that the mean residence time (MRT) was extended in the case of MTX-loaded p-MTX micelles, indicating a delayed MTX elimination from the bloodstream and prolonged in vivo residence time. Besides, the area under curve (AUC) of MTX-loaded p-MTX micelles was greater than free MTX, indicating a drug bioavailability improvement. Overall, MTX-loaded p-MTX micelles might be a promising nanosized drug delivery system for the cancer therapy.

Nanostructured lipid carriers used for oral delivery of oridonin: an effect of ligand modification on absorption.

Oridonin (Ori) is a natural compound with notable anti-inflammation and anti-cancer activities. However, therapeutic use of this compound is limited by its poor solubility and low bioavailability. Here a novel biotin-modified nanostructured lipid carrier (NLC) was developed to enhance the bioavailability of Ori. The effect of ligand (biotin) modification on oral absorption of Ori encapsulated in NLCs was also explored. Ori-loaded NLCs (Ori-NLCs) were prepared by the melt dispersion-high pressure homogenization method. Biotin modification of Ori-NLCs was achieved by EDC and NHS in aqueous phase. The obtained biotin-decorated Ori-NLCs (Bio-Ori-NLCs) were 144.9nm in size with an entrapment efficiency of 49.54% and a drug load of 4.81%. Oral bioavailability was enhanced by use of Bio-Ori-NLCs with a relative bioavailability of 171.01%, while the value of non-modified Ori-NLCs was improved to 143.48%. Intestinal perfusion showed that Ori solution unexpectedly exhibited a moderate permeability, indicating that permeability was not a limiting factor of Ori absorption. Ori could be rapidly metabolized that was the main cause of low bioavailability. However, there was a difference in the enhancement of bioavailability between Bio-Ori-NLCs and conventional NLCs. Although severe lipolyses happened both on Bio-Ori-NLCs and non-modified NLCs, the performance of Bio-Ori-NLCs in the bioavailability improvement was more significant. Overall, Bio-Ori-NLCs can further promote the oral absorption of Ori by a ligand-mediated active transport. It may be a promising carrier for the oral delivery of Ori.