Simultaneously Inhibiting P-gp Efflux and Drug Recrystallization Enhanced the Oral Bioavailability of Nintedanib.

INTRODUCTION: Nintedanib (NDNB) is a novel triple-angiokinase inhibitor for the treatment of lung cancer. However, the oral bioavailability of NDNB is only 4.7% owing to the poor solubility and the efflux of P-glycoprotein (P-gp). AIM: The aim was to explore the potential applications of a hydrogel of NDNB/hydroxypropyl-ß- cyclodextrin (HP-ß-CD) complex combined with a strong P-gp inhibitor Itraconazole (ITZ) for augmenting the oral delivery of NDNB. METHODS: The NDNB/HP-ß-CD complex was prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and molecular simulation and was subjected to in vitro and in situ studies. Then the NDNB/HP-ß-CD complex was dispersed in carbopol 934 hydrogel and the gel was evaluated for pharmacokinetic and pharmacodynamics studies. RESULTS: The HP-ß-CD and NDNB formed complex by van der Waals and hydrogen bonding interaction forces by XRD, FT-IR, and molecular simulation studies. When the molar ratio of NDNB/HP-ß-CD was 1:20, the complex exhibited high drug inclusion efficiency and excellent stability. The in situ perfusion results revealed that the permeability of the combination of complex and ITZ enhanced about 3.0-fold compared with the NDNB solution. The oral bioavailability of the sequential administration of ITZ and NDNB/HP-ß-CD complex gels was increased 3.5-fold by preventing recrystallization, extending the residence time in the gastrointestinal tract, and inhibiting P-gp in comparison with NDNB soft capsules. The co-therapy with NDNB/HP-ß-CD complex gels and ITZ exerted a strong anti-tumor effect. CONCLUSION: In conclusion, NDNB/HP-ß-CD complex gels combined with P-gp inhibitor were a potential strategy for enhancing the oral bioavailability and anti-tumor effect of NDNB.

Preparation, Characterization and in vitro/vivo Evaluation of Long-Acting Rivaroxaban-Loaded Microspheres.

BACKGROUND: Rivaroxaban is widely used for long-term prevention and maintenance therapy of thromboembolic disorders. The existing oral dosage forms of rivaroxaban lead to poor patient adherence because of repeated daily administration. The aim of this study is to design long-acting rivaroxaban- loaded microspheres to reduce dosing frequency and improve patient compliance. METHODS: Rivaroxaban-loaded microspheres were prepared using the emulsion-solvent evaporation method. The microspheres were evaluated in terms of morphology, particle size, drug loading and encapsulation efficiency, the physical state of the drug in the matrix, in vitro release/release mechanism, and in vivo pharmacokinetics in Sprague Dawley rats. RESULTS & DISCUSSION: Rivaroxaban-loaded microspheres presented spherical-shaped particles displaying a mean particle size of 89.3 µm, drug loading of 16.5% and encapsulation efficiency of 97.8%. The X-ray diffraction indicated that rivaroxaban existed in crystal form in the microspheres. in vitro release lasting approximately 50 days was characterized as a tri-phasic pattern: (1) an initial burst release, mainly due to the dissolution of drug particles with direct access to the microparticles' surface, (2) a "plateau" phase with a slow-release rate controlled by the diffusion and (3) a final, rapid drug release phase controlled by polymer erosion. Pharmacokinetic studies showed that rivaroxaban microspheres maintained a sustained release for more than 42 days. CONCLUSION: Rivaroxaban-loaded microspheres have great potential clinical advantages in reducing dosing frequency and improving patient compliance. The data obtained from this study could be used as scientific evidence for decision-making in future formulation development.

Bile acid transporter mediated STC/Soluplus self-assembled hybrid nanoparticles for enhancing the oral drug bioavailability.

The nano-particulate system for oral delivery faces a big challenge across the gastrointestinal bio-barriers. The aim was to explore the potential applications of bile acid transporter mediated the self-assembled hybrid nanoparticles (SHNPs) of sodium taurocholate (STC) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (Soluplus) for augmenting the oral delivery of poorly water-soluble drugs. Felodipine (FLDP) was chosen as a model drug. The self-assembly of STC with Soluplus to load FLDP and the microstructure of the SHNPs were confirmed using molecular simulation, STC determination by high performance liquid chromatography (HPLC) and transmission electron microscope. Results showed that STC was integrated with Soluplus on the surface of nanoparticles by hydrophobic interactions. The permeability of FLDP loaded STC/Soluplus SHNPs was STC dependent in the ileum, which was inhibited by the higher concentrations of STC and the inhibitor of apical sodium-dependent bile acid transporter (ASBT). STC/Soluplus (1:9) SHNPs significantly improved the drug loading of FLDP, achieved the highest permeability of FLDP and realized 1.6-fold of the area under the curve (AUC) of Soluplus self-assembled nanoparticles (SNPs). A water-quenching fluorescent probe P4 was loaded into the STC/Soluplus SHNPs, which verified that the SHNPs were transferred intactly across the ileum. In conclusion, STC/Soluplus SHNPs via ASBT are a potential strategy for enhancing the oral bioavailability of poorly water-soluble drugs.

Magnetic Reactive Oxygen Species Nanoreactor for Switchable Magnetic Resonance Imaging Guided Cancer Therapy Based on pH-Sensitive Fe5C2@Fe3O4 Nanoparticles.

Reactive oxygen species (ROS) are crucial molecules in cancer therapy. Unfortunately, the therapeutic efficiency of ROS is unsatisfactory in clinic, primarily due to their rigorous production conditions. By taking advantage of the intrinsic acidity and overproduction of H2O2 in the tumor environment, we have reported an ROS nanoreactor based on core-shell-structured iron carbide (Fe5C2@Fe3O4) nanoparticles (NPs) through the catalysis of the Fenton reaction. These NPs are able to release ferrous ions in acidic environments to disproportionate H2O2 into •OH radicals, which effectively inhibits the proliferation of tumor cells both in vitro and in vivo. The high magnetization of Fe5C2@Fe3O4 NPs is favorable for both magnetic targeting and T2-weighted magnetic resonance imaging (MRI). Ionization of these NPs simultaneously decreases the T2 signal and enhances the T1 signal in MRI, and this T2/T1 switching process provides the visualization of ferrous ions release and ROS generation for the supervision of tumor curing. These Fe5C2@Fe3O4 NPs show great potential in endogenous environment-excited cancer therapy with high efficiency and tumor specificity and can be guided further by MRI.

Novel Hot Melt Extruded Matrices of Hydroxypropyl Cellulose and Amorphous Felodipine-Plasticized Hydroxypropyl Methylcellulose as Controlled Release Systems.

Hydroxypropyl methylcellulose (HPMC) is a hydrophilic retarding-release polymer with the limited application in hot melt extrusion (HME) due to its high glass transition temperature (Tg 181-191°C) and melt viscosity. The aim of this study is to develop hot melt extruded matrices using hydroxypropyl cellulose (HPC) and felodipine (FLDP) with HPMC for controlled release and explore the relations of their specialty, processability, and structure with the product properties. Results showed that FLDP/HPCEF/HPMC can be extruded at 160°C with torques not more than 0.5 N·m. The extruded matrices of FLDP/HPCEF/HPMCK15M (10:45:45 and 30:35:35) achieved the controlled release for 24 h. Rheological behaviors demonstrated that HPCEF and FLDP were miscible with HPMCK15M, attaining maximum 30% FLDP soluble in the molten mixtures. HPCEF and FLDP decreased the complex viscosity and plasticized HPMCK15M to improve the extrusion processing. DSC and FT-IR indicated that the molten soluble FLDP was amorphous in the extruded matrices by hydrogen bonding with HPCEF/HPMCK15M. SEM/energy-dispersive X-ray microanalysis illustrated that the microstructure of extrudates was surface dense and interior loose, and FLDP was homogenously dispersed. Three-point bending test revealed that the plasticizers of HPCEF and FLDP contributed differently to the mechanical properties. HPCEF decreased the flexural modulus of HPMCK15M while that of HPCEF/HPMCK15M was increased by FLDP. Besides controlled release, low moisture absorption and enhanced stability were also the correlated achievements. Therefore, HPCEF-combined poorly water-soluble drugs to plasticize HPMCK15M provide an alternative novel potential approach to realize the controlled-release delivery via HME.

Bottom-Up and Top-Down Approaches to Explore Sodium Dodecyl Sulfate and Soluplus on the Crystallization Inhibition and Dissolution of Felodipine Extrudates.

The objectives of this study were to explore sodium dodecyl sulfate (SDS) and Soluplus on the crystallization inhibition and dissolution of felodipine (FLDP) extrudates by bottom-up and top-down approaches. FLDP extrudates with Soluplus and SDS were prepared by hot melt extrusion, and characterized by polarized light microscopy, differential scanning calorimetry, and fourier transform infrared spectroscopy. Results indicated that Soluplus inhibited FLDP crystallization, and the whole amorphous solid dispersions (ASDs) were binary FLDP-Soluplus (1:3) and ternary FLDP-Soluplus-SDS (1:2:0.15∼0.3 and 1:3:0.2∼0.4) extrudates. Internal SDS (5%-10%) decreased glass transition temperatures of FLDP-Soluplus-SDS ternary ASDs without presenting molecular interactions with FLDP or Soluplus. The enhanced dissolution rate of binary or ternary Soluplus-rich ASDs in the nonsink condition of 0.05% SDS was achieved. Bottom-up approach indicated that Soluplus was a much stronger crystal inhibitor to the supersaturated FLDP in solutions than SDS. Top-down approach demonstrated that SDS enhanced the dissolution of Soluplus-rich ASDs via wettability and complexation with Soluplus to accelerate the medium uptake and erosion kinetics of extrudates, but induced FLDP recrystallization and resulted in incomplete dissolution of FLDP-rich extrudates. In conclusion, top-down approach is a promising strategy to explore the mechanisms of ASDs' dissolution, and small amount of SDS enhances the dissolution rate of polymer-rich ASDs in the nonsink condition.

The Synergetic Effects of Nonpolar and Polar Protic Solvents on the Properties of Felodipine and Soluplus in Solutions, Casting Films, and Spray-Dried Solid Dispersions.

The aim was to explore the effects of nonpolar and polar protic solvents composed of dichloromethane (DCM) and ethanol (EtOH) on the properties of felodipine (FLDP) and Soluplus in solutions, casting films, and spray-dried drug-rich or polymer-rich solid dispersions (SDs). Measurement of intrinsic viscosity and solubility indicated that FLDP and Soluplus were miscible. EtOH-DCM ranging from 20:80 to 50:50 induced the strongest molecular interactions for FLDP-Soluplus-solvents systems. Accordingly, the casting films and spray-dried powders of FLDP and Soluplus were prepared using pure EtOH or DCM and their mixtures as solvents. Polarized light microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, in vitro dissolution tests, and stability have been conducted to characterize these films or spray-dried powders. EtOH-DCM (50:50) showed δH 2-3 MPa1/2 higher than FLDP and Soluplus. It exhibited stronger inhibitory effects on phase separation and recrystallization of amorphous FLDP than pure DCM or EtOH in the drug-rich casting films, spray drying process, and spray-dried SDs exposure to 40°C/RH75% for 1 month. Higher ratio of Soluplus may offset the effects of solvents on the dissolution and stability of polymer-rich SDs. In conclusion, combination of nonpolar and polar protic solvents is of high potential for spray drying to optimize drug-rich SDs.

Novel self-assembled tacrolimus nanoparticles cross-linking thermosensitive hydrogels for local rheumatoid arthritis therapy.

The aim was to explore the potential application of novel self-assembled nanoparticles cross-linking thermosensitive hydrogels composed of polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (Soluplus) and tacrolimus (FK-506) for local therapy of rheumatoid arthritis (RA). The sol-gel transition temperature (Tsol-gel), gelation time, rheological behaviors, in vitro release, in vivo gelation and retention, and therapeutic efficacy against adjuvant-induced arthritis (AIA) rats were compared between the Soluplus hydrogels and widely studied poloxamer 407 (P407) delivery systems. In sol, the spherical and uniform FK506 loaded Soluplus nanoparticles (Soluplus-SNPs) were self-assembled with encapsulation efficiency of 99.5±1.5% and particle size of 73.9±2.9nm. The decreased Tsol-gel of Soluplus-SNPs hydrogels was associated with the addition of salts, elevation of pH and ionic strength. The optimal Tsol-gel of Soluplus-SNPs with concentrations of 10%-30% in phosphate buffer (50mM, pH 7.4) was from 37.4±0.1°C to 32.8±0.3°C and the gelation time was not greater than 2min. Soluplus-SNPs gelling systems showed lower viscosity and wider range concentrations in sol state at 25°C and stronger gel strength at 37°C than P407, which resulting in longer sustained release of FK506 but without burst-release in vitro, and longer retention time in the local injection site in vivo. The therapeutic efficacy to treat AIA rats was significantly enhanced from d10 to d17 after a single dose of FK506 loaded in 10% and 20% Soluplus-SNPs hydrogels. In conclusion, Soluplus-SNPs hydrogel is a potential sustainable delivery system for FK506 to treat RA locally.

Optimization of a cationic liposome-based gene delivery system for the application of miR-145 in anticancer therapeutics.

In order to improve the delivery efficiency of microRNA (miRNA or miR)-145, the present study examined several factors which may affect cationic liposome (CL)-based transfection, including the hydration medium used for the preparation of liposomes, the quantity of the plasmid, the molar ratio of N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP)/cholesterol (chol), or DOTAP/chol, and the weight ratio of DOTAP/DNA. In order to enhance the transfection efficiency, protamine was selected as a DNA-condensing agent to form liposome­protamine­DNA (LPD) ternary complexes. An agarose gel retardation assay was used to examine the DNA binding affinity of the CLs. Following transfection, GFP fluorescence images were captured and flow cytometry was performed to determine the transfection efficiency. Furthermore, an MTT assay was performed to determine the cytotoxicity of the liposome complexes. The final optimal conditions were as follows: 5% glucose as the hydration medium, a molar ratio of DOTAP/chol at 3:1 for the preparation of CLs, a weight ratio of DOTAP/protamine/DNA of 3:0.5:1, with 8 µg plasmid added for the preparation of the LPD complexes. In vitro, the LPD complexes exhibited an enhanced transfection efficiency and low cytotoxicity, which indicated that the presented LPD vector enhanced the transfection efficiency of the CLs. The HepG2 cells were found to have the lowest expression levels of miR­145 out of the cell lines tested (A549, BGC-823, HepG2, HeLa, LoVo and MCF-7). Following the transient transfection of the HepG2 cells with miR­145, the results revealed that the overexpression of miR­145 inhibited the proliferation of the HepG2 cells and downregulated the expression of cyclin-dependent kinase 6 (CDK6), cyclinD1, c-myc, and Sp1 transcription factor (Sp1). In conclusion, in this study, we optimized a liposome­based delivery system for the efficient delivery of miR­145 into cancer cells. This may provide a foundation for further research into the use of miR­145 in anticancer therapeutics.

Liposomal oxymatrine in hepatic fibrosis treatment: formulation, in vitro and in vivo assessment.

The aim was to develop a liposomal oxymatrine conjugating D-alpha tocopheryl polyethylene glycol 1000 succinate (OMT-LIP) for enhanced therapeutics of hepatic fibrosis. OMT-LIP was prepared using the remote loading method. The influences of formulation compositions on the encapsulation efficiency of OMT-LIP were investigated. Mean particle size, zeta potential, morphology, in vitro release, fibrotic liver targeting, and therapeutics of OMT-LIP were thoroughly assessed. The intraliposomal buffer composition and concentration, extraliposomal phase composition and pH, types of phospholipid, lipid molar ratio composition, and theoretical drug loading are crucial factors to entrap OMT into liposomes. The optimum OMT-LIP presented spherically unilamellar microstructures with entrapment efficiency of 79.7 ± 3.9%, mean particle size of 121.6 ± 52.9 nm, and zeta potential of -5.87 mV. OMT-LIP significantly increased the accumulation of OMT in the fibrotic liver with an 11.5-fold greater AUC than OMT solution in the dimethylnitrosamine (DMN)-induced hepatic fibrosis animals. OMT-LIP could be a potential strategy to improve treatment outcomes for hepatic fibrosis, showing the protective effects to mice given CCl4 and the enhanced therapeutics to mice with either DMN or CCl4-induced hepatic fibrosis.

Formulation, antileukemia mechanism, pharmacokinetics, and biodistribution of a novel liposomal emodin.

Emodin is a multifunctional Chinese traditional medicine with poor water solubility. D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) is a pegylated vitamin E derivate. In this study, a novel liposomal-emodin-conjugating TPGS was formulated and compared with methoxypolyethyleneglycol 2000-derivatized distearoyl-phosphatidylethanolamine (mPEG2000-DSPE) liposomal emodin. TPGS improved the encapsulation efficiency and stability of emodin egg phosphatidylcholine/cholesterol liposomes. A high encapsulation efficiency of 95.2% ± 3.0%, particle size of 121.1 ± 44.9 nm, spherical ultrastructure, and sustained in vitro release of TPGS liposomal emodin were observed; these were similar to mPEG2000-DSPE liposomes. Only the zeta potential of -13.1 ± 2.7 mV was significantly different to that for mPEG2000-DSPE liposomes. Compared to mPEG2000-DSPE liposomes, TPGS liposomes improved the cytotoxicity of emodin on leukemia cells by regulating the protein levels of myeloid cell leukemia 1 (Mcl-1), B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein, which was further enhanced by transferrin. TPGS liposomes prolonged the circulation time of emodin in the blood, with the area under the concentration-time curve (AUC) 1.7 times larger than for free emodin and 0.91 times larger than for mPEG2000-DSPE liposomes. In addition, TPGS liposomes showed higher AUC for emodin in the lung and kidney than for mPEG2000-DSPE liposomes, and both liposomes elevated the amount of emodin in the heart. Overall, TPGS is a pegylated agent that could potentially be used to compose a stable liposomal emodin with enhanced therapeutics.

Preparation, therapeutic efficacy and intratumoral localization of targeted daunorubicin liposomes conjugating folate-PEG-CHEMS.

Folate polyethylene glycol-cholesterol hemisuccinate (folate-PEG-CHEMS) is a novel folate ligand firstly synthesized by our group and demonstrated good stability and potential targeting results on KB cells in vitro. The current study further explored endocytosis mechanisms of liposomes via folate receptor on L1210JF cells and assessed targeted therapeutic efficacy of folate-PEG-CHEMS anchored liposomes loading daunorubicin (F-L-DNR) in vivo. Folate-PEG-CHEMS was synthesized by a modified method. The liposome properties, cell cytotoxicity, intracellular and intratumoral localization, and therapeutic efficacy on a murine tumor model bearing L1210JF cells were evaluated. High encapsulation efficiency (95.1%±1.5%) and appropriate particle size (76.0±35.5nm) and zeta potential (-12.83±1.36mV) were achieved for F-L-DNR. IC(50) of F-L-DNR on L1210JF cells was 2-3-folds lower than that of non-targeted liposomal daunorubicin (L-DNR). Anticancer efficacy on L1210JF tumor model indicated that mice survival time of F-L-DNR group at doses of 5mg/kg and 10mg/kg was significantly longer than that of L-DNR or free DNR. Confocal fluorescence photographs of F-L-DNR indicated enhanced endocytosis of liposomes via folate receptor on L1210JF cells, prolonged retaining time in tumors and improved drug release in the tumor site at 24h post intravenous injection of F-L-DNR. In conclusion, folate-PEG-CHEMS is an effective ligand for folate-targeted daunorubicin liposomes to achieve increased drug release in tumor and therapeutic efficacy.

Triggering liposomal drug release with a lysosomotropic agent.

Drug release from liposomes in the endosome-lysosomal organelles into cytoplasm is critical to cytotoxicity and anticancer effects. Chloroquine is a lysosomotropic agent that has been reported to enhance in vitro cytotoxicity of basic anticancer drugs. To investigate the mechanism of chloroquine triggering basic anticancer drugs release from liposomes and the potential to treat solid tumors in clinic, daunorubicin was loaded into folate-targeted liposomes by ammonium sulfate remote loading method. In vitro triggered release profiles showed that chloroquine can instantly expel about 11% daunorubicin out of liposomes. In vitro cytotoxicity of folate-targeted liposomal daunorubicin on L1210JF(FR+) was enhanced by chloroquine, which was further confirmed by confocal micrographs. Intraliposomal pH was increased by adding chloroquine into 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) liposomes with ammonium sulfate gradient, but was not higher than 5.5. Ion exchange and pH rising are the most plausible mechanisms of chloroquine triggering daunorubicin release from liposomes. In vivo anticancer effects on a murine solid tumor model with L1210JF indicated that chloroquine induced daunorubicin release from liposomes as well. Overall, these results support the potential application of chloroquine to trigger the release of liposomal drugs and ultimately to improve the therapeutic efficacy.

[Inhibitive effect of local perfusion of tanshinone II A nanoparticles on MMP-2 secretion].

OBJECTIVE: To test the effect of Tanshinone II A nanoparticles on the expression of MMP-2. METHODS: Thirty five male New Zealand white rabbits were randomly divided into three groups. In group A (15 rabbits), the carotid arteries of the rabbits were stripped. In group B (5 rabbits) and C (15 rabbits), nanoparticles and Tanshinone II A nanoparticles were perfused respectively in the denudated arteries of the rabbits. The neointimal areas and the IOD values of MMP-2 secretion were measured. RESULTS: A significant reduction of neointimal hyperplasia in group C was found compared to the other two groups in terms of the intimal area and the intima-media ratio. Group C had significant lower IOD values than group A. CONCLUSION: Local administration of nanoparticles with incorporated Tanshinone I A not only inhibits neointimal hyperplasia but also inhibits the expression of MMP-2 in stripped arteries.

[The inhibitive effect produced by local perfusion of tanshinone IIA nanoparticle on neointimal hyperplasia of rabbit carotid artery following intimal denudation].

Tanshinone IIA nanoparticles were constructed and perfused in rabbit's right carotid after intimal denudation with ballon. Localization and retention at different time points of the coumarin-labeled drug nanoparticles were evaluated under laser confocal microscope. Nanoparticles were seen in the three layers of the cross-section artery. At 7 days, they were mainly deposited in the medial layer, while the deposition was generally observed in the adventitia and media at 14 days and 28 days. In the Tanshinone IIA nanoparticle study, a significant reduction of the neo-intimal hyperplasia was noted by comparing the intimal area and the intima-media ratio in the three groups. And the PLGA nanoparticles appeared to be fully biocompatible. As a result, the local administration of the nanoparticles with incorporated Tanshinone IIA showed not only the preventive effects, but aslo the high absorption and good biocompatability in the whole arterial wall.

Solid lipid nanoparticles of mitoxantrone for local injection against breast cancer and its lymph node metastases.

In an attempt to improve the therapeutic effect of mitoxantrone (MTO) against breast cancer and its lymph node metastases, solid lipid nanoparticles (SLN) of MTO were prepared, characterized and evaluated on mice. Film dispersion-ultrasonication method was used to prepare MTO-SLN, optimized by central composite design. MTO-SLN were prepared with a mean size of 61 nm, drug content (DC) of 4.18+/-0.10% and encapsulation yield (EY) of 87.23+/-2.16%. MTO-SLN were lyophilized and their mean size became 79 nm without significant change in DC and EY. The in vitro release study revealed a profile of sustained release of MTO from MTO-SLN without burst effect: the cumulative release rate Q24 h = 25.86 +/- 0.82%, t50 = (5.25 +/- 1.10)d and t90 = (28.38 +/- 4.50)d. The drug concentration of MTO-SLN in local lymph nodes was much higher and the drug concentrations in other tissues lower than that of MTO solution (MTO-Soln). Human MCF-7 breast cancer in nude mice and animal model of P388 lymph node metastases in Kunming mice were applied to investigate the therapeutic effects. There was no observed toxicity to the main tissues after local injection of MTO-SLN, but, for MTO-Soln, medium to serious toxicity to liver and lung was produced. The percent inhibition of MTO-SLN against breast cancer was 81.81 +/- 14.03%, while that of MTO-Soln with a double dose was 82.86 +/- 11.13%. The tests for lymph node metastases showed that MTO-SLN gave a mean size of lymph node of 41.85 +/- 27.42 mm3, while that of the MTO-Soln was 119.32 +/- 57.30 mm3 and that of the placebo was 186.83 +/- 77.71 mm3. This study opens a new perspective of active delivery of antitumor drug against breast cancer and its lymph node metastases with inspiring therapeutic effect and little side effects.

Mitoxantrone-loaded BSA nanospheres and chitosan nanospheres for local injection against breast cancer and its lymph node metastases. I: Formulation and in vitro characterization.

Positively charged mitoxantrone (MTO) was absorbed by negatively charged blank bovine serum albumin (BSA) and chitosan (CS) nanospheres to form MTO-BSA-NS and MTO-CS-NS, respectively. In addition to other conditions, values of pH of every step were optimized. On optimized conditions, MTO-BSA-NS of a mean size of 77 nm with an encapsulation yield (EY) of (98.86+/-1.43)% [drug loading rate (DL) (19.82+/-0.29)%] and MTO-CS-NS of a mean size of 75 nm with an EY of (97.57+/-1.00)% [DL (9.78+/-0.10)%] were obtained. After lyophilization and sterilization by (60)Co, the mean size increased about 10% but no significant change was observed in EY and DL. Tests for in vitro release in physiological saline or physiological saline containing 0.5% (w/v) ascorbic acid by a dialysis bag showed sustained release and little burst effect.

Mitoxantrone-loaded BSA nanospheres and chitosan nanospheres for local injection against breast cancer and its lymph node metastases. II: Tissue distribution and pharmacodynamics.

Bovine serum albumin (BSA) and chitosan (CS) nanospheres of mitoxantrone (MTO) were comparatively evaluated in terms of tissue distribution, acute toxicity and therapeutic efficiency against breast cancer and its lymph node metastases. After local injection in rats, MTO nanospheres showed a slower elimination rate and a much higher drug concentration in lymph nodes compared with MTO solution, and a lower drug concentration in other tissues. There was no observed acute toxicity to the main tissues of Kunming mice after local injection of MTO-BSA-NS. Mild toxicity to liver and lung was observed for MTO-CS-NS, but, for MTO solution, severe toxicity to liver and lung and much lower number of white blood cells were observed. Human MCF-7 breast cancer in nude mice and animal model of P388 lymph node metastases in Kunming mice were applied to investigate the therapeutic efficiency. The inhibition rate of the nanospheres against breast cancer was much higher than that of MTO solution, and lymph node metastases were efficiently inhibited by the nanospheres, especially MTO-BSA-NS.