Electrophoresis of human brain microvascular endothelial cells with uptake of cationic solid lipid nanoparticles: Effect of surfactant composition

Comparison between Polybutylcyanoacrylate Nanoparticles with Either Surface-Adsorbed or Encapsulated Brain-Derived Neurotrophic Factor on the Neural Differentiation of iPSCs

The brain-derived neurotrophic factor (BDNF) is vital in the neural differentiation of neural stem/progenitor cells, and together may have therapeutic potential for neural regeneration. In this study, a multiplexed polybutylcyanoacrylate nanoparticle (PBCA NP) delivery platform was constructed, incorporating either surface-adsorbed or encapsulated BDNF for the induction of neural differentiation in induced pleuripotent stem cells (iPSCs), where tween 80 (T80) and superparamagnetic iron oxide (SPIO) were added for central nervous system (CNS) targeting and magnetic resonance (MR) image tracking, respectively. Both methods by which the BDNF was carried resulted in loading efficiencies greater than 95%. The nanoparticle-mediated delivery of BDNF resulted in neural differentiation of iPSCs detected on immunofluorescence staining as early as 7 days, with enhanced differentiation efficiency by 1.3-fold compared to the control on flow cytometry; the delivery system of surface-adsorbed BDNF gave rise to cells that had the best neural development than the encapsulated formulation. T80-coating disrupted the in vitro blood–brain barrier model with a corresponding 1.5- to two-fold increase in permeability. SPIO-loaded PBCA NPs exhibited a concentration-dependent, rapid decay in signal intensity on the phantom MR experiment. This study demonstrates the versatility of the PBCA NP, and the surface-adsorption of BDNF is the preferred method of delivery for the differentiation of iPSCs.

Harnessing nanostructured systems for improved treatment and prevention of HIV disease

Combination antiretroviral therapy effectively controls human immunodeficiency virus (HIV) viral replication, delaying the progression to acquired immune deficiency syndrome and improving and extending quality of life of patients. However, the inability of antiretroviral therapeutics to target latent virus and their poor penetration of viral reserve tissues result in the need for continued treatment for the life of the patient. Side effects from long-term antiretroviral use and the development of drug resistance due to patient noncompliance are also continuing problems. Nanostructured systems of antiretroviral therapeutics have the potential to improve targeted delivery to viral reservoirs, reduce drug toxicity, and increase dosing intervals, thereby improving treatment outcomes and enhancing patient adherence. Despite these advantages, very few nanostructured antiretroviral delivery systems have made it to clinical trials due to challenges in preclinical and clinical development. In this context, we review the current challenges in HIV disease management, and the recent progress in leveraging the unique performance of nanostructured systems in therapeutic delivery for improved treatment and prevention of this incurable human disease.

Effect of surface charge on the brain delivery of nanostructured lipid carriers in situ gels via the nasal route

The aim of this study was to investigate the influence of the nanocarrier surface charge on brain delivery of a model hydrophilic drug via the nasal route. Anionic and cationic nanostructured lipid carriers (NLCs) were prepared and optimized for their particle size and zeta potential. The optimum particles were incorporated in poloxamer in situ gels and their in vivo behavior was studied in the plasma and brain after administration to rats. Optimum anionic and cationic NLCs of size <200 nm and absolute zeta potential value of ≈ 34 mV were obtained. Toxicity study revealed mild to moderate reversible inflammation of the nasal epithelium in rats treated with the anionic NLCs (A7), and destruction of the lining mucosal nasal epithelium in rats treated with the cationic NLCs (C7L). The absolute bioavailability of both drug loaded anionic and cationic NLCs in situ gels was enhanced compared to that of the intranasal solution (IN) of the drug with values of 44% and 77.3%, respectively. Cationic NLCs in situ gel showed a non significant higher Cmax (maximum concentration) in the brain compared to the anionic NLCs in situ gel. Anionic NLCs in situ gel gave highest drug targeting efficiency in the brain (DTE%) with a value of 158.5 which is nearly 1.2 times that of the cationic NLCs in situ gel.

Nanoparticle formulation improves the anticonvulsant effect of clonazepam on the pentylenetetrazole-induced seizures: behavior and electroencephalogram

To document the efficacy of clonazepam (CLZ) either free as a solution or loaded in solid lipid nanoparticles (CLZ-SLN) or mixed micelles (CLZ-MM), the in vitro blood-brain barrier permeability of the formulations was determined. Behavior and/or electroencephalograms (EEGs) of rodents receiving treatments were also studied. The in vitro permeability of CLZ increased when associated with SLN, but decreased in the case of MM. The occurrence of the pentylenetetrazole (PTZ)-induced seizures in mice was significantly prevented by CLZ, even when exposed a lower dose of CLZ-SLN after administration by the oral route. The behavioral severity and EEGs showing the PTZ-induced paroxystic activity in rats diminished significantly in the presence of CLZ alone (0.3 mg/kg), and were almost totally prevented in the rats treated with CLZ-SLN (equivalent to 0.3 mg/kg). The frequency, duration, and spreading of the spikes-wave of rats treated with CLZ-SLN decreased significantly as compared with CLZ alone, CLZ-MM, or the vehicle. These results show an in vitro-in vivo correlation in the enhanced blood-brain barrier permeability of SLN formulation, and a contribution of MM to the carrier effect of drugs toward the bloodstream and brain, where this pharmaceutical formulation of CLZ-SLN improves the anticonvulsant effect of this benzodiazepine, thus offering additional advantages after oral administration.

In vivo real-time fluorescence visualization and brain-targeting mechanisms of lipid nanocarriers with different fatty ester:oil ratios

AIMS

The objective of the present work was to investigate the influence of the inner cores of lipid nanocarriers on the efficiency of brain targeting. Cetyl palmitate and squalene were respectively chosen as the solid lipid and liquid oil in the inner phase of the nanocarriers.

MATERIALS & METHODS

Nanoparticulate systems with different cetyl palmitate/squalene ratios were compared by evaluating the size, zeta potential, molecular environment, and mobility of lipids in the systems.

RESULTS

The particulate diameter ranged from 190 to 210 nm, with systems containing 100% cetyl palmitate in the matrix (solid lipid nanoparticles [SLN]) showing the smallest size, followed by systems with both cetyl palmitate and squalene (nanostructured lipid carriers [NLC]) and with 100% squalene (lipid emulsions [LE]). A cationic surfactant, Forestall, was used to produce a positive surface charge of 40-55 mW. The in vitro release was evaluated using various dyes located in different phases of the nanocarriers. The release of sulforhodamine B occurred in a sustained manner from the shell of the nanocarriers. The in vivo brain distribution of lipid nanosystems after an intravenous injection into rats was monitored by a real-time fluorescence imaging system. LE showed higher brain accumulation than SLN and NLC. NLC only exhibited a slightly higher brain accumulation compared with the aqueous control. Incorporation of sulforhodamine B into LE could prolong its retention in the brain from 20 to 50 min. The results were further confirmed by imaging the entire brain and brain slices. The specific association of lipid nanocarriers with rat brain endothelial cells (bEnd3) was demonstrated using fluorescence microscopy. The cellular uptake of LE and SLN was higher compared with NLC and the aqueous control. LE were observed to be internalized by cells through caveola-mediated and macropinocytotic energy-dependent endocytosis.

CONCLUSION

The experimental profiles indicated that LE with moderate additives are a promising brain-targeting nanocarrier. The composition of the lipid matrix played a significant role in delivering compounds to the brain.

Targeting nevirapine delivery across human brain microvascular endothelial cells using transferrin-grafted poly(lactide-co-glycolide) nanoparticles

Aims: Poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) were grafted with transferrin (Tf) to enhance the transport of nevirapine (NVP) across human brain microvascular endothelial cells (HBMECs). Methods: NVP-loaded PLGA NPs with surface-grafting Tf (Tf/NVP–PLGA NPs) were incubated with HBMECs and immunochemical staining characterized Tf receptors (TfRs). Results: The polydispersity index of Tf/NVP–PLGA NPs was lower than 0.008. The entrapment efficiency of NVP and loading efficiency of Tf was 20–75% and 15–80%, respectively. Tf slightly retarded the release of NVP from PLGA. Dioctadecyldimethylammonium bromide (DODAB)-stabilized Tf/NVP–PLGA NPs reduced the viability of HBMECs to 70–75%. The secretion of TNF-α was inhibited by Tf and stimulated by DODAB. The permeability of NVP across HBMECs reached maxima at 67% DODAB and 0.1–0.2% Tf. An increase in the concentration of Tf enhanced the uptake of Tf/NVP–PLGA NPs via a TfR-mediated mechanism. Conclusion: Tf/NVP–PLGA NPs are efficacious carriers in targeting delivery across HBMECs for viral therapy.

Physicochemical characterization and in vivo bioluminescence imaging of nanostructured lipid carriers for targeting the brain: apomorphine as a model drug

Nanostructured lipid carriers (NLCs) were prepared to investigate whether the duration of brain targeting and accumulation of drugs in the brain can be improved by intravenous delivery. NLCs were developed using cetyl palmitate as the lipid matrix, squalene as the cationic surfactant, and Pluronic F68, polysorbate 80 and polyethylene glycol as the interfacial additives. Solid lipid nanoparticles (SLNs) and lipid emulsions (LEs) were also prepared for comparison. An anti-Parkinson's drug, apomorphine, was used as the model drug. Nuclear magnetic resonance and differential scanning calorimetry showed possible interactions between the solid and liquid lipids in the inner core. The lipid nanoparticles with different compositions were characterized by mean size, zeta potential, apomorphine encapsulation and in vitro drug release. NLCs were 370-430 nm in size, which was between the sizes of the SLNs and LEs. A cationic surfactant was used to produce a positive surface charge of 42-50 mV. The base form of apomorphine was successfully entrapped by NLCs with an entrapment percentage of > 60%. The loading of apomorphine in nanoparticles resulted in a slower release behavior compared to the aqueous solution, with LEs showing the lowest release. In vivo real-time bioluminescence imaging of the rat brain revealed that NLCs could be targeted, through certain vessels, to selected brain regions. This effect was further confirmed by imaging the entire brain and brain slices. The results indicated that NLCs with moderate additives are a promising controlled-release and drug-targeting system.