Polymeric nanocarriers for nose-to-brain drug delivery in neurodegenerative diseases and neurodevelopmental disorders

Neurodegenerative diseases are progressive conditions that affect the neurons of the central nervous system (CNS) and result in their damage and death. Neurodevelopmental disorders include intellectual disability, autism spectrum disorder, and attention-deficit/hyperactivity disorder and stem from the disruption of essential neurodevelopmental processes. The treatment of neurodegenerative and neurodevelopmental conditions, together affecting ∼120 million people worldwide, is challenged by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier that prevent the crossing of drugs from the systemic circulation into the CNS. The nose-to-brain pathway that bypasses the BBB and increases the brain bioavailability of intranasally administered drugs is promising to improve the treatment of CNS conditions. This pathway is more efficient for nanoparticles than for solutions, hence, the research on intranasal nano-drug delivery systems has grown exponentially over the last decade. Polymeric nanoparticles have become key players in the field owing to the high design and synthetic flexibility. This review describes the challenges faced for the treatment of neurodegenerative and neurodevelopmental conditions, the molecular and cellular features of the nasal mucosa and the contribution of intranasal nano-drug delivery to overcome them. Then, a comprehensive overview of polymeric nanocarriers investigated to increase drug bioavailability in the brain is introduced.

Engineering a folic acid-decorated ultrasmall gemcitabine nanocarrier for breast cancer therapy: Dual targeting of tumor cells and tumor-associated macrophages

Combination of passive targeting with active targeting is a promising approach to improve the therapeutic efficacy of nanotherapy. However, most reported polymeric systems have sizes above 100 nm, which limits effective extravasation into tumors that are poorly vascularized and have dense stroma. This will, in turn, limit the overall effectiveness of the subsequent uptake by tumor cells via active targeting. In this study, we combined the passive targeting via ultra-small-sized gemcitabine (GEM)-based nanoparticles (NPs) with the active targeting provided by folic acid (FA) conjugation for enhanced dual targeted delivery to tumor cells and tumor-associated macrophages (TAMs). We developed an FA-modified prodrug carrier based on GEM (PGEM) to load doxorubicin (DOX), for co-delivery of GEM and DOX to tumors. The co-delivery system showed small particle size of ∼10 nm in diameter. The ligand-free and FA-targeted micelles showed comparable drug loading efficiency and a sustained DOX release profile. The FA-conjugated micelles effectively increased DOX uptake in cultured KB cancer cells that express a high level of folate receptor (FR), but no obvious increase was observed in 4T1.2 breast cancer cells that have a low-level expression of FR. Interestingly, in vivo, systemic delivery of FA-PGEM/DOX led to enhanced accumulation of the NPs in tumor and drastic reduction of tumor growth in a murine 4T1.2 breast cancer model. Mechanistic study showed that 4T1.2 tumor grown in mice expressed a significantly higher level of FOLR2, which was selectively expressed on TAMs. Thus, targeting of TAM may also contribute to the improved in vivo targeted delivery and therapeutic efficacy.

Development of fluorescent- and radio-traceable T1307-polymeric micelles as biomedical agents for cancer diagnosis: biodistribution on 4T1 tumor-bearing mice

Abstract In recent years, nanocarriers have been studied as promising pharmaceutical tools for controlled drug-delivery, treatment-efficacy follow-up and disease imaging. Among them, X-shaped amphiphilic polymeric micelles (Tetronic®, poloxamines) display great potential due to their biocompatibility and non-toxic effects, among others. In the present work, polymeric micelles based on the T1307 copolymer were initially decorated with a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-fluorophore in order to determinate its in vivo biodistribution on 4T1 tumor-bearing mice. However, unfavorable results with this probe led to two different strategies. On the one hand, the BODIPY-micelle-loaded, L-T1307-BODIPY, and on the other hand, the 99mTc-micelle-radiolabeled, L-T1307- 99m Tc, were analyzed separately in vivo. The results indicated that T1307 accumulates mainly in the stomach, the kidneys, the lungs and the tumor, reaching the maximum organ-accumulation 2 hours after intravenous injection. Additionally, and according to the results obtained for L-T1307- 99m Tc, the capture of the polymeric micelles in organs could be observed up to 24 hours after injection. The results obtained in this work were promising towards the development of new radiotracer agents for breast cancer based on X-shaped polymeric micelles.

Lapatinib-loaded nanocolloidal polymeric micelles for the efficient treatment of breast cancer

This study aims at preparing and evaluating lapatinib-loaded polymeric micelles for the better treatment of breastcancer (BC). LP-loaded polymeric micelles (LP-PMs) were prepared as per our previous studies by using Soluplus®as the polymer. Therefore, we employed the lyophilization technique using mannitol as a cryoprotectant and furtherconducted in vitro and in vivo anticancer efficacy studies, in addition to our previously reported works. We found thatthe lyophilized LP-PMs were sufficiently stable and retained encapsulated drugs. Furthermore, their smooth surfacewas visualized on the atomic force microscopy. The X-ray powder diffractogram of LP-PMs showed successfulencapsulation of Lapatinib; however, the presence of few drug molecules on the surface was evidenced by energydispersive X-ray analysis. Furthermore, LP-PMs showed sustained release of drugs, with selective drug release in anacidic environment, resembling that of a tumor. The LP-PMs exhibited higher cytotoxicity against SKBr3 BC cellsand also induced effective inhibition of the growth of the tumor in vivo when compared to that of lapatinib solutionand marketed formulation. The results of this study indicate the greater potential of LP-PMs for the efficient treatmentfor BC

Polymeric micelles containing resveratrol: development, characterization, cytotoxicity on tumor cells and antimicrobial activity

Antimicrobial and antitumor activities of resveratrol, a compound found mainly in grapes, have already been demonstrated. However, its low bioavailability is a limiting factor for therapeutic application. Polymeric micelles can be an approach to solve this problem since they can encapsulate hydrophobic substances. We developed and characterized micellar formulations containing resveratrol and evaluated their cytotoxic and antimicrobial effects. The formulations were prepared by the cold dispersion method with different concentrations of F127 (5 or 10% w/w) and resveratrol (500 or 5000 µM). The formulations were characterized according to size, polydispersity index, pH, encapsulation rate and in vitro release. Cytotoxic effect was evaluated on a bladder cancer cell line and antimicrobial effect was evaluated on E. coli, S. aureus and C. albicans. One of the formulations (10% w/w of F127 and 5000 µM of resveratrol) was a monodispersed solution with high encapsulation rate, thus it was chosen for the cytotoxicity and antimicrobial assays. MS- 10+RES-3 was able to preserve the antimicrobial and cytotoxic activity of resveratrol. This is the first study that evaluated antimicrobial potential and cytotoxicity of micelles containing resveratrol on bladder cancer cells and the results showed that micellar nanostructures could ensure the maintenance of the biological activity of resveratrol.

Cytotoxicity and cellular uptake of paclitaxel-loaded carboxymethyl chitosan-rhein polymeric micelles in MCF-7 cells / 中国药科大学学报

@#In this study, in vitro cytotoxicity of carboxymethyl chitosan-rhein conjugate(CR conjugate)and paclitaxel-loaded carboxymethyl chitosan-rhein polymeric micelles(PTX/CR PMs)was evaluated by MTT method in MCF-7 cells. The results showed that CR conjugate displayed good security; PTX/CR PMs in 24 h showed better antitumor activity than Taxol® . Environment-responsive fluorescent probe P4 was used to determine the cellular uptake of PTX/CR PMs in MCF-7 cells. The results also showed that P4 and PTX co-loaded carboxymethyl chitosan-rhein polymeric micelles ［(P4+PTX)/CR PMs］ could be taken up by MCF-7 cells. There was no difference between(P4+PTX)/CR PMs group and(P4+PTX)/CR PMs with verapamil group, suggesting that CR PMs could protect fluorescent probe and/or drugs in their cores avoiding efflux by P-glycoprotein. These results will contribute to in vivo study of CR conjugate and PTX/CR PMs in the future.

Application of Polymeric Micelles in Transdermal Drug Delivery Systems / 中国药师

Objective: To review the application of polymeric micelles as the vehicles in transdermal delivery systems.Methods: Based on the recently published papers, the researches of preparation, penetration mechanism, drug release and application of polymeric micelles in transdermal delivery systems were classified and summarized.Results: Polymeric micelles were extensively applied as drug vehicles due to the ability of solubilization and transdermal absorption enhancement.Conclusion: Polymeric micelles can be used as promising vehicles in transdermal delivery systems, which show a good application prospect.

Determination of Encapsulation Efficiency and Medicine Loading and Release ofβ-elemene inβ-elemene-loaded Nano Polymeric Micelles / 中国中医药信息杂志

Objective To establish a RP-HPLC method for the determination of encapsulation efficiency (EE) and medicine loading (ML) in β-elemene-loaded Nano Polymeric Micelles; To study its release characteristic in vitro. Methods DSPE-PEG2000 was used as carrier to prepare medicine-loaded micelles. EE and ML were determined by petroleum ether extraction method, and its release characteristic in vitro was studied by dialysis method. Results The average EE and ML ofβ-elemene-loaded Nano Polymeric Micelles were 89.47%and 8.33%, respectively. Its release characteristic was slow. Conclusion The method for EE and ML determination is simple and accurate, and the prepared micelles have the property of sustained release.

Comparison of pharmacokinetics of curcumin in rats administered with two kinds of polymeric micelles / 中国中药杂志

To investigate the effect of end-capped modification of mPEG-PLA with Boc-phenylalanine(BP) on pharmacokinetic characteristics of curcumin(CUR) loaded micelles, and then provide experimental evidence for prescription optimization. Healthy male SD rats were randomly divided into three groups and they were intravenously administered with a single injection of CUR-mPEG-PLA micelles, CUR-mPEG-PLA-BP micelles and reference formulations DMSO solution(n=6). The doses were 20 mg•kg⁻¹ in term of CUR. Blood samples were collected before and after administration, and the concentration of curcumin in blood plasma was determined by HPLC to draw time-concentration curve. Non-compartmental pharmacokinetic parameters were calculated by using DAS 2.0 software and statistical analysis was conducted between the different groups. The results indicated that the pharmacokinetic characteristics of CUR-mPEG-PLA micelles were similar to those of the free drug of CUR dissolved in DMSO, and the main pharmacokinetic parameters had no significant difference between the two groups. However, as compared with CUR-mPEG-PLA micelles, CUR-mPEG-PLA-BP micelles had a significantly increased area under the time-concentration curve(AUC), significantly prolonged half-life of elimination(tl/2) and mean residence time(MRT), and reduced total body clearance(Cl) (P<0.05). In conclusion, the amphipathic block copolymer of mPEG-PLA-BP could provide curcumin loaded micelles with preferable pharmacokinetic properties in vivo, and CUR-mPEG-PLA-BP micelles were worthy of further research and development.

Preparation and properties of docetaxel-loaded nanobubbles / 国际药学研究杂志

Objective To optimize the formulation and preparation technology of docetaxel (DTX)-loaded nanobubbles, and evaluate their properties. Methods The best ratio of methoxypoly(ethylene glycol)-poly(.DL-lactide-co-glycolide) (mPEG-PLGA) and different membrane stabilizers were optimized with Langmuir membrane balance. DTX-Loaded nano-micelles were encapsulated by mPEG-PLGA with an injection method. Nanoemulsions was formed after being added with perfluoropentane (PFP, the boiling point of 29.5 °C) as the organic phase. The formulations and preparation techniques of nanoemulsions were optimized and the conditions of nanobubbles formulaion was also evaluated. Cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was evaluated with the MTT method. Results The best ratio of mPEG-PLGA and Span 20 was 10: 1 (mol/mol). The membrane elasticity of the prepared nanobubbles with optimized formulations and the preparation techniques was good. In addition, they were obviously temperature-sensitive and ultrasonic-sensitive. The particle size of nanobubbles increased with higher temperature and decreased with lower temperature. The size of nanobubbles increased upon ultrasound application and then decreased a little. The cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was obvious and dose-dependent. Conclusion DTX-Loaded nanobubbles are a novel formulation with tumor-targeted and ultrasound-sensitive drug release.

Preparation and Determination of Entrapment Efficiency of Puerarin Polymeric Micelles / 中国药房

OBJECTIVE:To prepare Puerarin polymeric micelles and establish a method to determine its entrapment efficiency. METHODS:Puerarin polymeric micelles were prepared by film dispersion method. The polymeric micelles and free drug were sepa-rated by centrifugal-millipore filter filtration method. The entrapment efficiency of puerarin polymeric micelles was determined by HPLC. Diamonsil C18(2)column was used with 1% citric acid solution-methanol(65∶35)at the flow rate of 1 ml/min. The detec-tion wavelength was set at 250 nm,and column temperature was room temperature. RESULTS:The prepared polymeric micelles were spherical and spherical-like in shape with a mean particle size of 54.12 nm,polydispersity index of 0.122,Zeta potential of -13.60 mV;the linear range of puerarin was 2-10μg/ml(R2=0.999 4)with average recovery rate of 99.2%(RSD=0.9%,n=3). The re-covery rate of free drug was 95.3%(RSD=1.7%,n=3). The mean entrapment efficiency and drug-loading amount of puerarin were(35.5±2.12)% and(0.3±0.07)%,respectively(n=3). CONCLUSIONS:Film dispersion method is suitable for the prepara-tion of Puerarin polymeric micelles. Established method is convenient,accurate and reliable for the content and entrapment efficien-cy determination of Puerarin polymeric micelles.

Preparation and properties of docetaxel-loaded nanobubbles / 国际药学研究杂志

Objective To optimize the formulation and preparation technology of docetaxel(DTX)-loaded nanobubbles,and evaluate their properties. Methods The best ratio of methoxypoly(ethylene glycol)-poly(DL-lactide-co-glycolide)(mPEG-PLGA) and different membrane stabilizers were optimized with Langmuir membrane balance. DTX-Loaded nano-micelles were encapsulated by mPEG-PLGA with an injection method. Nanoemulsions was formed after being added with perfluoropentane(PFP,the boiling point of 29.5℃)as the organic phase. The formulations and preparation techniques of nanoemulsions were optimized and the conditions of nanobubbles formulaion was also evaluated. Cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was evaluated with the MTT meth?od. Results The best ratio of mPEG-PLGA and Span 20 was 10∶1(mol/mol). The membrane elasticity of the prepared nanobubbles with optimized formulations and the preparation techniques was good. In addition,they were obviously temperature-sensitive and ultra?sonic-sensitive. The particle size of nanobubbles increased with higher temperature and decreased with lower temperature. The size of nanobubbles increased upon ultrasound application and then decreased a little. The cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was obvious and dose-dependent. Conclusion DTX-Loaded nanobubbles are a novel formulation with tumor-targeted and ultra?sound-sensitive drug release.

Preparation of Redox-responsive Pluronic F127 Micelles with High Drug-loading Efficiency / 中国药房

OBJECTIVE:To prepare redox-responsive pluronic F127 micelles with high drug-loading efficiency. METHODS:The thiol derivative F127-SH with strong hydrophobicity was synthesized by introducing tert-butyl methacrylate and cysteamine to the hydrophobic segments of F127. Paclitaxel (PTX)-loaded redox-responsive pluronic F127 micelles with high drug-loading effi-ciency(F127-SS/PTX)were prepared by film-hydration method as well as oxidation reaction of thiol groups. The diameter,encap-sulation efficiency and drug-loading amount were detected,and the change of diameter and drug release behavior of micelles were investaged under reducing environment or non-reducing environment. RESULTS:Mean diameter of F127-SS/PTX micelles was about(77.87±1.79)nm,and encapsulation efficiency and drug-loading amount were(92.73±2.35)% and(16.25±0.99)%,re-spectively. The diameter of the micelles increased rapidly and drug release rate of PTX increased significantly in the presence of 10 mmol/L dithiothreitol. CONCLUSIONS:The redox-responsive pluronic F127 micelles with high drug-loading efficiency are pre-pared successfully.

Research Progress in Polymeric Micelles Used for Tumor Targeting Drug Delivery Systems / 中国药师

Polymeric micelles as effective drug carriers have been paid wide attention. They have many considerable advantages in cancer therapy, such as high efficiency, long acting and high drug loading etc. The paper reviewed the type, preparation materials and drug lording methods of polymeric micelles, especially discussed the targeting strategy of tumor-targeting drug delivery systems and the ap-plication examples of polymeric micelles in targeting drug delivery systems.

Preparation,physicochemical properties and anti-tumor activity of polymeric micelles of one gemcitabine lipid derivative / 中国药理学与毒理学杂志

OBJECTIVE Topreparealipidderivativeofgemcitabine(Gem)anditspolymericmi-celles to overcome the disadvantages of Gem.METHODS N-benzyl-3′-acetyl-gemcitabine(BAG)was synthesized.A BAG-loaded poloxamer polymeric micelle (BAG∶poloxamer 188 =10∶1 ,mol/mol)was prepared using an injection method.The micelles were characterized with a laser particle size and elec-tric charge instru ment and negatively-stained trans mission electron microscopy.Hu man breast cancer cells MCF-7 were cultured with Gem or BAG polymeric micelles of 5,10,20,30,50,70,90 μmol·L-1 for 24,48 and 72 h,respectively.The inhibitory rate of cells was measured with an MTT method.The MCF-7 cytotoxicity of BAG polymeric micelles was investigated.A pharmacodynamic study was per-formed on the mice bearing mouse hepatocellular cancer cells H22.Intravenous (iv)and oral (ig)ad-ministration was used at the dose of Ge m 40 mg·kg -1 or BAG polymeric micelles 62 mg·kg -1 .The mice were administered on the 1 st,4th and 7th day and sacrificed on the 8th day.Tumor inhibitory rates were measured.RESULTS TheBAGstructurewasidentifiedbythinlayerchromatograph,1Hand13C NMR,infrared ray chromatograph and mass spectrum.The appearance of BAG micelles was a slightly blue suspension.The micelles were spheres according to the electron microscopic observation.Their size was 62.82 nm and the zeta potential was -18.8 mV.The half inhibition concentration (IC50)of Gem and BAG polymeric micelles was 40.6 and 90.0 μmol·L-1 ,5.0 and 14.9 μmol·L-1 ,5.0 and 1 3.6 μmol·L-1 at 24,48 and 72 h,respectively according to the MTT results.According to the in vivo results,compared with the tumor model group,Gem (ig),Gem (iv)and BAG polymeric micelles (iv and ig)had significant effect on the tumor weight of H22 cell xenograft mice (P<0.01 ).As for anti-tumor efficiency,BAG polymeric micelles (ig)were better than Gem (ig)(P<0.05);BAG polymeric micelles (iv)were better than BAG polymeric micelles (ig)(P<0.05),and BAG polymeric micelles (iv)were almostequaltoGem(iv).CONCLUSION ThelipidderivativeofGemcanbeloadedinthepoloxamer 1 88 polymeric micelles.BAG polymeric micelles show in vitro MCF-7 cell inhibition and in vivo inhibition of mouse H22 xerografts;iv or ig.BAG polymeric micelles (ig)show better anti-tumor effect than Gem (ig),indicating that BAG polymeric micelles are a promising novel anti-tumor oral preparation.

Study on antitumor activity of paclitaxel-loaded polymeric micelles / 国际生物医学工程杂志

Objective To develop paclitaxel-loaded polymeric micelles from poly (ε-caprolactone)-poly (ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL),and to evaluate in vitro cytotoxicity as well as in vivo antitumor activity against EMT-6 tumor breast cell.Methods Paclitaxel-loaded polymeric micelles were prepared by thin-film hydration and ultrasonic method.The physical status of paclitaxel inside the polymeric micelles was investigated by differential scanning calorimetry (DSC).In vitro cytotoxicity of paclitaxel-loaded polymeric micelles against EMT-6 cell line was assessed by MTT assay.In vivo anticancer activity was evaluated against EMT-6 tumorbearing mice,with commercially available Taxol injection as control.Results Paclitaxel-loaded polymeric micelles exhibited homogeneous spherical shapes with apparent core-shell morphology.The average diameter of paclitaxelloaded polymeric micelles was 93 nm.DSC study indicated that paclitaxel was in solid amorphous state after being encapsulated in the polymeric micelles.In vitro cytotoxicity demonstrated that the cytotoxic effect of paclitaxelloaded polymeric micelles was lower than that of Taxol injection at the same paclitaxel content.Paclitaxel-loaded polymeric micelles showed greater tumor growth-inhibition effect in vivo on EMT-6 breast tumor in comparison with that of Taxol injection,with tumor growth inhibition of 85.79％ and 63.37％,respectively (P＜0.05).Conculsions The prepared paclitaxel-loaded polymeric micelles showed high anti-tumoral efficacy and low toxicity,and might have the potential to be developed as an effective anticancer drug-delivery system for cancer chemotherapy.

Polymeric micelles and molecular modeling applied to the development of radiopharmaceuticals

Micelles composed of amphiphilic copolymers linked to a radioactive element are used in nuclear medicine predominantly as a diagnostic application. A relevant advantage of polymeric micelles in aqueous solution is their resulting particle size, which can vary from 10 to 100 nm in diameter. In this review, polymeric micelles labeled with radioisotopes including technetium (99mTc) and indium (111In), and their clinical applications for several diagnostic techniques, such as single photon emission computed tomography (SPECT), gamma-scintigraphy, and nuclear magnetic resonance (NMR), were discussed. Also, micelle use primarily for the diagnosis of lymphatic ducts and sentinel lymph nodes received special attention. Notably, the employment of these diagnostic techniques can be considered a significant tool for functionally exploring body systems as well as investigating molecular pathways involved in the disease process. The use of molecular modeling methodologies and computer-aided drug design strategies can also yield valuable information for the rational design and development of novel radiopharmaceuticals.

Micelas poliméricas compostas de copolímeros ligadas a um elemento radioativo são utilizadas em Medicina Nuclear com aplicação predominantemente diagnóstica. A vantagem relevante da utilização de micelas poliméricas em solução aquosa é o tamanho de suas partículas, as quais podem variar de 10 a 100 nm de diâmetro. Neste trabalho de revisão são apresentadas micelas poliméricas marcadas com radioisotopos, como tecnécio-99m (99mTc) e índio-111 (111In), assim como suas aplicações clínicas em técnicas de diagnóstico como Tomografia por emissão de Fóton Único (Single photon Emission Computed Tomography - SPECT), cintilografia, e Ressonância Magnética Nuclear (RMN). Neste contexto, sua aplicação em diagnóstico de sistema linfático e linfonodo sentinela recebe atenção especial. O emprego de técnicas de diagnóstico pode ser considerado uma ferramenta importante para a exploração de sistemas no organismo humano assim como para a investigação de caminhos moleculares envolvidos nos processos de diversas doenças. O uso de metodologias de modelagem molecular e estratégias de desenvolvimento de fármacos assistidas computacionalmente também pode fornecer informações valiosas para o planejamento e o desenvolvimento racional de novos radiofármacos.