Enhancing Methotrexate Delivery in the Brain by Mesoporous Silica Nanoparticles Functionalized with Cell-Penetrating Peptide using in Vivo and ex Vivo Monitoring.

The blood-brain barrier (BBB) acts as a physical/biochemical barrier that protects brain parenchyma from potential hazards exerted by different xenobiotics found in the systemic circulation. This barrier is created by "a lipophilic gate" as well as a series of highly organized influx/efflux mechanisms. The BBB bottleneck adversely affects the efficacy of chemotherapeutic agents in treating different CNS malignancies such as glioblastoma, an aggressive type of cancer affecting the brain. In the present study, mesoporous silica nanoparticles (MSNs) were conjugated with the transactivator of transcription (TAT) peptide, a cell-penetrating peptide, to produce MSN-NH-TAT with the aim of improving methotrexate (MTX) penetration into the brain. The TAT-modified nanosystem was characterized by Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and N2 adsorption-desorption analysis. In vitro hemolysis and cell viability studies confirmed the biocompatibility of the MSN-based nanocarriers. In addition, in vivo studies showed that the MTX-loaded MSN-NH-TAT improved brain-to-plasma concentration ratio, brain uptake clearance, and the drug's blood terminal half-life, compared with the use of free MTX. Taken together, the results of the present study indicate that MSN functionalization with TAT is crucial for delivery of MTX into the brain. The present nanosystem represents a promising alternative drug carrier to deliver MTX into the brain via overcoming the BBB.

Systemic delivery of parathyroid hormone (1-34) using spray freeze-dried inhalable particles.

Pulmonary delivery of peptides remains an important, noninvasive route of administration that is attractive because it offers high bioavailability and patient compliance. Optimization of particle characteristics for deposition in the deep regions of the lung after inhalation and retention of peptide stability are key challenges to their delivery to the lungs. The present study investigated the use of spray freeze-drying to produce porous inhalable parathyroid hormone (1-34)-loaded microparticles suitable for pulmonary delivery. The influence of different excipients in the medium of water or citrate buffer on microparticles characteristics, peptide stability and its systemic delivery in rats were evaluated. Using leucine at 10% (w/w) and hydroxy propyl-ß-cyclodextrin (HPßCD) at 0.04% (w/w) in water or citrate medium preserved parathyroid hormone (1-34) stability by spray freeze-drying. Aerosol performance showed that leucine was more effective than HPßCD in producing inhalable microparticles. Nevertheless, there was no statistical difference between bioavailabilities of HPßCD containing formulations and leucine-containing formulations in the presence of citrate buffer; and even in the presence of water, HPßCD resulted in higher bioavailability compared to leucine. The high absolute bioavailability (up to 47.25%) of formulations could facilitate replacement of injected form of parathyroid hormone (1-34) by dry powder inhaler form.

Diatom-guided bone healing via a hybrid natural scaffold.

Bone tissue engineering (BTE) involves the design of three-dimensional (3D) scaffolds that aim to address current challenges of bone defect healing, such as limited donor availability, disease transmission risks, and the necessity for multiple invasive surgeries. Scaffolds can mimic natural bone structure to accelerate the mechanisms involved in the healing process. Herein, a crosslinked combination of biopolymers, including gelatin (GEL), chitosan (CS), and hyaluronic acid (HA), loaded with diatom (Di) and ß-sitosterol (BS), is used to produce GCH-Di-S scaffold by freeze-drying method. The GCH scaffold possesses a uniform structure, is biodegradable and biocompatible, and exhibits high porosity and interconnected pores, all required for effective bone repair. The incorporation of Di within the scaffold contributes to the adjustment of porosity and degradation, as well as effectively enhancing the mechanical property and biomineralization. In vivo studies have confirmed the safety of the scaffold and its potential to stimulate the creation of new bone tissue. This is achieved by providing an osteoconductive platform for cell attachment, prompting calcification, and augmenting the proliferation of osteoblasts, which further contributes to angiogenesis and anti-inflammatory effects of BS.

Correction to "Targeted Reinforcement of Macrophage Reprogramming Toward M2 Polarization by IL-4-Loaded Hyaluronic Acid Particles".

[This corrects the article DOI: 10.1021/acsomega.8b03182.].

Targeted Reinforcement of Macrophage Reprogramming Toward M2 Polarization by IL-4-Loaded Hyaluronic Acid Particles.

Alteration of macrophage polarization from inflammatory (M1) to anti-inflammatory (M2) phenotype can have striking implications for the regeneration of injured tissues, treatment of inflammatory diseases, and relief of autoimmune disorders. Although certain cytokines like interleukin (IL)-4 and IL-13 are capable of inducing M2 macrophage polarization, their therapeutic potential in vivo is suffering from low efficacy due to their instability and poor access to target cells. Here, we report the synthesis of IL-4-loaded hyaluronic acid (HA) particle for the targeted delivery of cytokines through the high affinity of HA to CD44 receptors of macrophages. HA carriers composed of low, middle, and high molecular weight (MW) polymers were synthesized using divinyl sulfone (DVS) cross-linking. The MW of HA had a negligible effect on the physicochemical properties and biocompatibility of the macrophages, but as an indicative of M2 polarization, a significant change in the arginase-1 (Arg-1) activity, TNF-α release, and IL-10 secretion was observed for the HA particles prepared with high MW polymers. Therefore, these particles were loaded with IL-4 for simultaneous macrophage targeting and M1 to M2 reprogramming, evidenced by a remarkable increase in the Arg-1 to iNOS ratio, as well as CD163 and CD206 upregulation in the M1 macrophages, which were initially triggered by lipopolysaccharide and interferon-γ.

The effect of excipients on the stability and aerosol performance of salmon calcitonin dry powder inhalers prepared via the spray freeze drying process.

Spray freeze drying was developed to produce dry powders suitable for applications such as inhalation delivery. In the current study, the spray freeze drying technique was employed to produce inhalable salmon calcitonin microparticles. Effects of the carrier type, concentration of hydroxyl propyl-ß-cyclodextrin and the presence of Tween 80 on the chemical and structural stability, as well as on the aerosol performance of the particles were investigated. The results indicated that hydroxyl propyl-ß-cyclodextrin had the most important effect on the chemical stability of the powder and strongly increased its stability by increasing its concentration in the formulation. Chemically stable formulations (over 90 % recovery) were selected for further examinations. Fluorescence spectroscopy and circular dichroism suggested that the formulations were structurally stable. Aerosol performance showed that the Tween-free powders produced higher fine particle fraction values than the formulations containing Tween (53.7 vs. 41.92 % for trehalose content and 52.85 vs. 43.06 % for maltose content).