Cholesterol–PEG comodified poly (N-butyl) cyanoacrylate nanoparticles for brain delivery: in vitro and in vivo evaluations

This study investigated cholesterol–polyethylene glycol (PEG) comodified poly (ethyleneglycol)-poly (lactide) nanoparticles (CLS-PEG NPs) as a novel, biodegradable brain drug delivery system and included an evaluation of its in vitro and in vivo properties. To this end, coumarin-6 (C6), a fluorescent probe, was encapsulated into CLS-PEG NPs by an emulsion polymerization method. We reported that the use of CLS-PEG NPs led to a sustained drug release in vitro. Additionally, cell viability experiments confirmed their safety. The uptake and transport of CLS-PEG NPs, by bEnd.3 cells (an immortalized mouse brain endothelial cell line), was significantly higher than that of a control C6 solution. An investigation of the uptake mechanisms of different NP formulations demonstrated that cholesterol modifications may be the primary way to improve the efficiency of cellular uptake, wherein macropinocytosis may be the most important endocytic pathway in this process. An investigation of the transport mechanisms of CLS-PEG NPs also implicated macropinocytosis, energy and cholesterol in bEnd.3 cells lines. Following an intravenous (IV) administration to rats, pharmacokinetic experiments indicated that C6-loaded CLS-PEG NPs achieved sustained release for up to 12?h. In addition, IV delivery of CLS-PEG NPs appeared to significantly improve the ability of C6 to pass through the blood–brain barrier: the concentration of C6 found in the brain increased nearly 14.2-fold when C6 CLS-PEG NPs were used rather than a C6 solution. These in vitro and in vivo results strongly suggest that CLS-PEG NPs are a promising drug delivery system for targeting the brain, with low toxicity.     

Solid lipid nanoparticles for transdermal delivery of diclofenac sodium: preparation, characterization and in vitro studies

The aim of this study was to prepare diclofenac sodium (DNa) solid lipid nanoparticles (SLNs) by a modified emulsion/solvent evaporation method for transdermal delivery. Five independent processing parameters including the lipid matrix, emulsifiers, co-emulsifiers, water-dispersed phase and organic phase were assessed systematically to enhance the entrapment of DNa. The SLNs produced by optimal formulation were submicrometre size with low polydispersity index, the entrapment efficiency was about 89% and the drug loading was about 9.5%. Shape and surface morphology were determined by transmission electron microscopy, which revealed the fairly spherical and core-shell shapes of the SLNs. The in?vitro release of SLNs showed a two-step release pattern: one initial burst release followed by a second slow-release phase. In the in?vitro cutaneous permeation studies, value of flux obtained for DNa solution was higher than that of SLNs suspension. SLNs had also been shown to improve the dermal localization of DNa.     

A novel hydrogel plug of Sterculia urens for pulsatile delivery: in vitro and in vivo evaluation

The objective of this study was to investigate a novel hydrogel plug using isolated root mucilage of Sterculia urens to obtain a desired lag time for an oral chronotherapeutic colon-specific pulsatile drug delivery of indomethacin. Pulsatile drug delivery was developed using chemically treated hard gelatin capsule bodies filled with eudragit multiparticulates of indomethacin, and sealed with different hydrogel plugs (root mucilage of S. urens, xanthan gum, guar gum, HPMC K4M and combination of maltodextrin with guar gum). Indomethacin multiparticulates were prepared using extrusion spheronization, spray drying and solvent evaporation techniques with Eudragit? L-100 and S-100 (1:2) by varying drug-to-polymer ratio. After oral administration, the water-soluble cap of capsule dissolved in the intestinal fluid and the hydrogel plug swells. After a controlled time, the swollen plug subsequently ejected from the dosage form, releases the contents of the capsule. The formulation factors affecting the drug release were concentration and types of hydrogel plug used. In?vivo gamma scintigraphy study in healthy rabbits proved the capability of the system to release drug in lower parts of the gastrointestinal tract after a programmed lag time. This study demonstrates that the indomethacin multiparticulates could be successfully colon-targeted by the design of time and pH-dependent modified chronopharmaceutical formulation. In conclusion, the investigated novel hydrogel plug could be a valuable tool for achieving desired lag time.     

Nanoparticle-mediated delivery of oligonucleotides to the blood–brain barrier: in vitro and in situ brain perfusion studies on the uptake mechanisms

Abstract

Except for the few exceptions where topical administration is feasible, progress towards broad clinical application of nucleic acid therapeutics requires development of effective systemic delivery strategies. The central nervous system represents a particularly difficult organ for systemic delivery due to the blood–brain barrier. We previously reported a nanoparticulate delivery system for targeted brain delivery of oligonucleotides upon systemic administration, i.e. liposome-encapsulated polyethylenimine/oligonucleotides polyplexes. In this study, cellular uptake and intracellular trafficking of the nanoparticles were further investigated using in situ brain perfusion technique followed by colocalization and fluorescence resonance energy transfer techniques. The brain endothelial uptake and possibly parenchymal accumulation were readily visualized upon administration via internal carotid artery perfusion. The nanoparticles were colocalized with early-endosome antigen, which confirms the brain endothelial uptake through transferrin receptor-mediated endocytosis. Fluorescence resonance energy transfer analysis also suggested the nanoparticles entered the brain endothelial cells while maintaining their integrity. Together, the enhanced brain uptake, as claimed previously, of the antibody-targeted nanoparticles was clearly confirmed with more convincing evidences. In addition, the experimental techniques described here should be applicable to the studies involving nanoparticle-mediated brain delivery of nucleic acid therapeutics.     

Glutathione PEGylated liposomes: pharmacokinetics and delivery of cargo across the blood–brain barrier in rats

Abstract

Partly due to poor blood–brain barrier drug penetration the treatment options for many brain diseases are limited. To safely enhance drug delivery to the brain, glutathione PEGylated liposomes (G-Technology®) were developed. In this study, in rats, we compared the pharmacokinetics and organ distribution of GSH-PEG liposomes using an autoquenched fluorescent tracer after intraperitoneal administration and intravenous administration. Although the appearance of liposomes in the circulation was much slower after intraperitoneal administration, comparable maximum levels of long circulating liposomes were found between 4 and 24?h after injection. Furthermore, 24?h after injection a similar tissue distribution was found. To investigate the effect of GSH coating on brain delivery in vitro uptake studies in rat brain endothelial cells (RBE4) and an in vivo brain microdialysis study in rats were used. Significantly more fluorescent tracer was found in RBE4 cell homogenates incubated with GSH-PEG liposomes compared to non-targeted PEG liposomes (1.8-fold, p?<?0.001). In the microdialysis study 4-fold higher (p?<?0.001) brain levels of fluorescent tracer were found after intravenous injection of GSH-PEG liposomes compared with PEG control liposomes. The results support further investigation into the versatility of GSH-PEG liposomes for enhanced drug delivery to the brain within a tolerable therapeutic window.     

β-Hydroxybutyric acid grafted solid lipid nanoparticles: A novel strategy to improve drug delivery to brain

Delivery of drugs to brain is an elusive task in the therapy of many serious neurological diseases. With the aim to create a novel formulation to enhance the drug uptake to brain, betreliesoxybutyric acid (HBA) grafted docetaxel loaded solid lipid nanoparticles (HD-SLNs) were explored. Transportation of HD-SLNs relies on the transport of novel ligand, HBA, by monocarboxylic acid transporter (MCT1). Expression of MCT1 transporter on brain endothelial cells (bEnd cells) was studied using immunocytochemistry. Stearylamine–HBA conjugate was used to modify the surface of SLNs and it was confirmed using XPS (X-Ray Photon Spectroscopy) analysis. In vitro release studies revealed the controlled release of drug from HD-SLNs. Cytotoxicity and cell uptake studies revealed the increased uptake of docetaxel with HD-SLNs. Mechanism involved in the uptake of HD-SLNs was studied in bEnd cells by saturating MCT1 with excess HBA. Pharmacokinetic and brain distribution demonstrated increased docetaxel concentrations in brain compared with Taxotere®.From the Clinical EditorThe authors of this study demonstrate enhanced drug delivery to the brain using a novel formulation of beta-hydroxybutyric acid grafted docetaxel loaded solid lipid nanoparticles. The results show increased uptake of docetaxel compared with Taxotere.     

Paclitaxel-loaded polyester nanoparticles prepared by spray-drying technology: in vitro bioactivity evaluation

Paclitaxel (PTX), an antimicrotubular agent used in the treatment of ovarian and breast cancer, was encapsulated in nanoparticles (NPs) of poly(lactide-co-glycolide) (PLGA) and poly(ε-caprolactone) (PCL) polymers using the spray-drying technique. Morphology, size distribution, drug encapsulation efficiency, thermal degradation and drug release were characterized. MCF7 cells were employed to evaluate the efficacy of the systems on cell cycle and cytotoxicity. The particle size was in the range 0.8-1?μm. The incorporation efficiency of PTX was more than 80% in all NPs obtained. In?vitro drug release took place during 35 days, and drug release rates were in the order PCL?>?PLGA 50:50?>?PLGA 75:25. Unloaded NPs showed to be cytocompatible at MCF7 cells. PTX-loaded NPs demonstrated the release of the drug block cells in the G2/M phase. All PTX-loaded formulations showed their efficacy in killing MCF7 cells, mainly PTX-loaded PLGA 50:50 and PLGA 75:25 that cause a decrease in cell viability lower than 20%.     

Salmon calcitonin-loaded Eudragit® and Eudragit®-PLGA nanoparticles: in vitro and in vivo evaluation

The main objective of this study was to prepare salmon calcitonin (sCT)-loaded Eudragit?RSPO, Eudragit?L100 and Eudragit?-poly(lactic-co-glycolic acid) blend nanoparticles for in vitro and in vivo evaluation as an oral drug delivery system. The prepared nanoparticles ranged in size from 179.7 to 308.9?nm with a polydispersity index between 0.051 and 2.75, and had surface charges ~ -11 to +6?mV. Efficient sCT encapsulation and release was observed with all the nanoparticle formulations. The polymer type was an important factor that influenced the release characteristics and the in vivo hypocalcemic effect. Nanoparticle formulations were also prepared with sodium taurodeoxycholate (NaTDC) and characterized. No statistically significant difference was noted between the hypocalcemic effect of any of the nanoparticle formulations with and without NaTDC (p?>?0.05). The use of Eudragit?RSPO nanoparticles appears to be a potential approach for the oral delivery of sCT.     

The potential for nanoparticle-based drug delivery to the brain: overcoming the blood–brain barrier

The development of blood–brain barrier (BBB)-targeting technologies is a very active field of research: targeting therapeutic actives to the central nervous system by means of systemic administration means crossing the BBB, and this is now one of the most challenging problems in drug development. The BBB is a unique regulatory system that protects the brain environment by separating it from direct contact with the circulating blood. In doing so, it impedes at the same time the access of a large number of diagnostic and therapeutic agents into the brain parenchyma. One of the possibilities of bypassing this barrier relies on specific properties of nanoparticulate vectors designed to interact with BBB-forming cells at a molecular level, as a result of which the transport of drugs or other molecules (such as nucleic acids, proteins or imaging agents) could be achieved without interfering with the normal function of the brain. This article summarises several recent example applications, presents emerging work and highlights the directions for further developments in this area.     

Enhanced anti-glioblastoma efficacy by PTX-loaded PEGylated poly(ɛ-caprolactone) nanoparticles: In vitro and in vivo evaluation

The aim of this work was to investigate the anti-tumor effect of paclitaxel (PTX)-loaded methoxy poly(ethylene glycol)-poly(?-caprolactone) nanoparticles (MPEG-NP/PTX) against glioblastoma multiforme (GBM). MPEG-NP/PTX was prepared by the emulsion and evaporation technique with particle size of 72.5±2.2nm and did not change remarkably during the period of 21-day storage at 4°C. The drug-loading coefficient and encapsulation ratio of optimized formulation were 8.2±0.6% and 90.4±2.3%, respectively. The in vitro release behavior exhibits a biphase release manner and was affected by PEG segment. In vitro cytotoxicity was assessed using C6 cell lines and was compared to Taxol and PTX-loaded poly(?-caprolactone) conventional nanoparticles (NP/PTX). Cell viability assay against C6 cells exhibited higher or at least comparable cytotoxicity than that of Taxol and NP/PTX. More importantly, in vivo real-time fluorescence imaging analysis in intracranial C6 glioblastoma bearing mice showed that the methoxy poly(ethylene glycol)-poly(?-caprolactone) nanoparticles (MPEG-NP) displayed much stronger fluorescence signal and 3-fold larger Area-Under-Curve (AUC) than poly(?-caprolactone) conventional nanoparticles (NP) in tumor-bearing brain. Furthermore, in vivo anti-glioblastoma effect exhibited the mean survive time of MPEG-NP/PTX (28 days) was much longer than those of Taxol injection (20 days) and NP/PTX (23 days). Therefore, MPEGylated poly(?-caprolactone) nanoparticles significantly enhanced the anti-glioblastoma activity of PTX and might be considered a promising drug delivery system against advanced glioblastoma.     

Microencapsulation of budesonide with dextran by spray drying technique for colon-targeted delivery: an in vitro/in vivo evaluation in induced colitis in rat

The aim of this study was developing colon targeted-delivery of budesonide for ulcerative colitis. Microcapsules were prepared using spray drying technique by different drug-to-dextran ratios and three molecular weights (MWs) of polymer. Differential scanning calorimetry, X-ray diffraction (XRD), drug release and loading efficiency of microcapsules were studied. In?vivo efficacy of the selected formulation prepared by 1?:?10 drug-to-polymer ratio and dextran with MW 500?000 (D10M500) against acetic acid-induced colitis in rats was evaluated and compared to the control and reference groups (mesalasine and budesonide suspensions). The results showed that D10M500 microcapsules could target the drug to colon and its efficacy in reducing macroscopic damage score was higher than mesalasine suspension. Treatment with D10M500 decreased the scores of crypt damage and total colitis significantly compared to the control group which just received the vehicle and the groups treated with mesalasine and budesonide suspension which could not reduce the colitis parameters significantly.     

Intranasal delivery of tapentadol hydrochloride–loaded chitosan nanoparticles: formulation,characterisation and its in vivo evaluation

The aim of the present investigation was to formulate tapentadol hydrochloride–loaded chitosan nanoparticles (CS-NPs) for nose to brain delivery. Chitosan nanoparticles were prepared using ionotropic gelation technique. Optimisation of the formulation and process parameters was done using Box–Behnken Design. The entrapment efficiency, drug loading, Z-average size and zeta potential of the optimised batch were 63.49?±?1.61%, 17.25?±?1.38%w/w, 201.2?±?1.5?nm and +49.3?mV, respectively. In-vitro release study showed 84.04?±?1.53% drug release after 28?h, while ex vivo studies indicated higher permeation of CS-NPs through nasal mucosa. The nanoparticles exhibited good mucoadhesiveness, haemocompatibility and safety as evidenced by histopathology. The results of the pharmacodynamic study revealed prolongation of the analgesic activity. The intranasal instillation of CS-NPs resulted in the higher concentrations in brain compared to the drug solution and intravenous administration of CS-NPs. In a nutshell, intranasal administration of tapentadol hydrochloride–loaded CS-NPs is a promising approach for effective pain management.     

Novel in situ gelling ocular inserts for voriconazole-loaded niosomes: design,in vitro characterisation and in vivo evaluation of the ocular irritation and drug pharmacokinetics

This work aimed to develop voriconazole in situ gelling ocular inserts loaded with niosomal suspension. Niosomes and mixed niosomes were prepared using span 40 and span 60 with pluronic L64 and pluronic F127. The entrapment efficiency percentages (EE%), mean vesicle size, polydispersity index (PI), zeta potential and in vitro drug release of these niosomes were evaluated. F3-mixed niosomes prepared with span 60 and pluronic L64 was selected, due to its highest EE; optimum vesicle size with smallest PdI and suitable release pattern of the drug (63% after 8?h). In situ ocular inserts were prepared using sodium carboxymethylcellulose (CMC Na) and sodium alginate (ALG) and characterised for surface morphology, surface pH, water uptake, mucoadhesion and in vitro release. ALG in situ ocular insert (S₂) was selected for further in vivo evaluation of the ocular irritation and drug pharmacokinetics in the aqueous humour of rabbit's eyes. S₂ in situ gelling ocular insert was non-irritant and showed significantly (p?<?0.01) higher C_max, delayed T_max and increased bioavailability.     

Exploration of Wedelia chinensis leaf-assisted silver nanoparticles for antioxidant,antibacterial and in vitro cytotoxic applications

Green synthetic route of silver nanoparticles (AgNPs) has already been proved to be an advantageous over other physico-chemical approaches due to its simplicity, cost effectiveness, ecofriendly and nontoxicity. In this finding, aqueous Wedelia chinensis leaf extract (WLE) mediated synthesis of AgNPs was approached. Surface plasmon resonance (SPR) band at 408 nm preliminary indicated the formation of AgNPs, while TEM and XRD characterization confirmed the formation of spherically shaped and crystalline AgNPs with an average size of 31.68 nm, respectively. The plausible biomolecules in the aqueous leaf extract responsible for the reduction and stabilization of AgNPs were identified by FTIR analysis and found to be polyphenolic groups in flavonoid. Further, synthesized AgNPs was explored for different biological applications. Biosynthesized AgNPs showed significant free radical scavenging activity as compared to Wedelia leaf extract and antibacterial activity against clinically isolated test pathogens where Gram-negative bacteria were found more susceptible to AgNPs than Gram-positive one. In addition, in vitro cytotoxic response was also evaluated on hepatocellular carcinoma Hep G2 cell lines and showed a dose-dependent cytotoxic response with an IC₅₀ value of 25 μg/mL.     

Preparation and in vitro–in vivo evaluation of surface-modified poly(lactide-co-glycolide) nanoparticles as controlled release carriers for flutamide delivery

Abstract

This investigation explores the use of methoxy polyethylene glycol (mPEG) functionalised poly(d,l-lactide-co-glycolide) (PLGA) nanocrystals of flutamide (FLT) with enhanced solubility, bioavailability and blood circulation time for targeting prostate cancer. FLT had Log P 3.27, short half life 5–6?h, low water solubility, permeability and bioavailability with extensive first-pass metabolism. FLT-loaded nanocrystals were prepared using nanoprecipitation method with surface coating by mPEG and characterised through differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electronic microscopy, particle size, zeta potential, percent entrapment efficiency (% EE), in vitro dissolution, haemolysis, sterility, bioavailability and stability studies. The percent cumulative drug release and % EE of optimised formulation was found to be 95.21?±?1.18 and 88.36?±?1.20, respectively, for 48?h. In addition, FLT-loaded PEGylated PLGA nanocrystals exhibited significantly delayed blood clearance with drug level of about 766.71?ng/mL at 48?h. In conclusion, PEGylated PLGA FLT nanocrystals could be demonstrated as a novel approach to enhance solubility, bioavailability and blood circulation time.     

Direct nose to brain drug delivery via integrated nerve pathways bypassing the blood–brain barrier: an excellent platform for brain targeting

Introduction: The blood–brain barrier (BBB) represents a stringent barrier for delivery of neurotherapeutics in vivo. An attempt to overcome this barrier is represented by the direct transport of drugs from the nose to the brain along the olfactory and trigeminal nerve pathways. These nerve pathways initiate in the nasal cavity at olfactory neuroepithelium and terminate in the brain. An enormous range of neurotherapeutics, both macromolecules and low molecular weight drugs, can be delivered to the central nervous system (CNS) via this route.

Areas covered: Present review highlights the literature on the anatomy-physiology of the nasal cavity, pathways and mechanisms of neurotherapeutic transport across nasal epithelium and their biofate and various strategies to enhance direct nose to brain drug delivery. The authors also emphasize a variety of drug molecules and carrier systems delivered via this route for treating CNS disorders. Patents related to direct nose to brain drug delivery systems have also been listed.

Expert opinion: Direct nose to brain drug delivery system is a practical, safe, non-invasive and convenient form of formulation strategy and could be viewed as an excellent alternative approach to conventional dosage forms. Existence of a direct transport route from the nasal cavity to the brain, bypassing the BBB, would offer an exciting mode of delivering neurotherapeutic agents.     

Protein binding modulates the cellular uptake of silver nanoparticles into human cells: Implications for in vitro to in vivo extrapolations?

Nanoparticles (NP) absorbed in the body will come in contact with blood proteins and form NP/protein complexes termed protein coronas, which may modulate NP cellular uptake. This study quantitated human epidermal keratinocyte (HEK) uptake of silver (Ag) NP complexed to different human serum proteins. Prior to HEK dosing, AgNP (20 nm and 110 nm citrate BioPure™; 40 nm and 120 nm silica-coated) were preincubated for 2 h at 37 °C without (control) or with physiological levels of albumin (44 mg/ml), IgG (14.5 mg/ml) or transferrin (3 mg/ml) to form protein-complexed NP. HEK were exposed to the protein incubated AgNP for 3 h, rinsed and incubated for 24 h, rinsed in buffer and lysed. Ag was assayed by inductively-coupled plasma optical emission spectrometry. Uptake of Ag in HEK was <4.1% of applied dose with proteins suppressing citrate, but not silica coated Ag uptake. IgG exposure dramatically reduced 110 nm citrate AgNP uptake. In contrast, greatest uptake of 20 nm silica AgNP was seen with IgG, while 110 nm silica AgNP showed minimal protein effects. Electron microscopy confirmed cellular uptake of all NP but showed differences in the appearance and agglomeration state of the NP within HEK vacuoles. This work suggests that NP association with different serum proteins, purportedly forming different protein coronas, significantly modulates Ag uptake into HEK compared to native NP uptake, suggesting caution in extrapolating in vitro uptake data to predict behavior in vivo where the nature of the protein corona may determine patterns of cellular uptake, and thus biodistribution, biological activity and toxicity.     

Development of chitosan–pullulan composite nanoparticles for nasal delivery of vaccines: in vivo studies

Abstract

Here, we aimed at developing chitosan/pullulan composite nanoparticles and testing their potential as novel systems for the nasal delivery of diphtheria toxoid (DT). All the chitosan derivatives [N-trimethyl (TMC), chloride and glutamate] and carboxymethyl pullulan (CMP) were synthesised and antigen-loaded composites were prepared by polyion complexation of chitosan and pullulan derivatives (particle size: 239–405?nm; surface charge: +18 and +27?mV). Their immunological effects after intranasal administration to mice were compared to intramuscular route. Composite nanoparticles induced higher levels of IgG responses than particles formed with chitosan derivative and antigen. Nasally administered TMC–pullulan composites showed higher DT serum IgG titre when compared with the other composites. Co-encapsulation of CpG ODN within TMC-CMP-DT nanoparticles resulted in a balanced Th₁/Th₂ response. TMC/pullulan composite nanoparticles also induced highest cytokine levels compared to those of chitosan salts. These findings demonstrated that TMC-CMP-DT composite nanoparticles are promising delivery system for nasal vaccination.