Effects of solvent used for fabrication on drug loading and release kinetics of electrosprayed temozolomide-loaded PLGA microparticles for the treatment of glioblastoma

The application of electrosprayed minocycline-loaded PLGA microparticles for the treatment of glioblastoma

The survival of patients with glioblastoma multiforme (GBM), the most common and invasive form of malignant brain tumors, remains poor despite advances in current treatment methods including surgery, radiotherapy, and chemotherapy. Minocycline is a semi-synthetic tetracycline derivative that has been widely used as an antibiotic and more recently, it has been utilized as an antiangiogenic factor to inhibit tumorigenesis. The objective of this study was to investigate the utilization of electrospraying process to fabricate minocycline-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles with high drug loading and loading efficiency and to evaluate their ability to induce cell toxicity in human glioblastoma (i.e., U87-MG) cells. The results from this study demonstrated that solvent mixture of dicholoromethane (DCM) and methanol is the optimal solvent combination for minocycline and larger amount of methanol (i.e., 70:30) resulted in a higher drug loading. All three solvent ratios of DCM:methanol tested produced microparticles that were both spherical and smooth, all in the micron size range. The electrosprayed microparticles were able to elicit a cytotoxic response in U87-MG glioblastoma cells at a lower concentration of drug compared to the free drug. This work provides proof of concept to the hypothesis that electrosprayed minocycline-loaded PLGA microparticles can be a promising agent for the treatment of GBM and could have potential application for cancer therapies.

Novel biodegradable molecularly imprinted polymer nanoparticles for drug delivery of methotrexate anti-cancer; synthesis, characterization and cellular studies

BACKGROUND

Recently biodegradable nanoparticles are the center of attention for the development of drug delivery systems. Molecularly imprinted polymer (MIP) is an interesting candidate for designing drug nano-carriers. MIP-based nanoparticles could be used for cancer treatment and exhibited the potential to fill gaps regarding to ligand-based nanomaterials. Also, the presence of a cross-linker can play an essential role in nanoparticle stability and physicochemical properties of nanoparticles after synthesis.

OBJECTIVES

In this research, a biodegradable drug delivery system based on MIP nanoparticles was prepared using a biodegradable cross-linker (dimethacryloyl hydroxylamine, DMHA) for methotrexate (MTX). A hydrolysable functional group CO-O-NH-CO was added to the crosslinking agent to increase the final biodegradability of the polymer.

METHODS

Firstly, a biodegradable cross-linker was synthesized. Then, the non-imprinted polymers were prepared through mini-emulsion polymerization in the absence of a template; and efficient particle size distribution was determined. Finally, methotrexate was placed in imprinted polymers to achieve the desired MIP. Different types of MIPs were synthesized using different molar ratios of template, cross-linker, and functional monomer, and the optimal molar ratio was obtained at 1:4:20, respectively.

RESULTS

HNMR successfully confirmed the chemical structure of the cross-linker. According to SEM images, nanoparticles had a spherical shape with a smooth surface. The imprinted nanoparticles showed a narrow size distribution with an average of 120 nm at a high ratio of cross-linker. The drug loading and entrapment efficiency were 6.4% and 92%, respectively. The biodegradability studies indicated that the nanoparticles prepared by DMHA had a more degradability rate than ethylene glycol dimethacrylate as a conventional cross-linker. Also, the polymer degradation rate was higher in alkaline environments. Release studies in physiological and alkaline buffer showed an initial burst release of a quarter of loaded MTX during the day and a 70% release during a week. The Korsmeyer-Peppas model described the release pattern. The cytotoxicity of MTX loaded in nanoparticles was studied on the MCF-7 cell line, and the IC50 was 3.54 μg/ml.

CONCLUSION

It was demonstrated that nanoparticles prepared by DMHA have the potential to be used as biodegradable drug carriers for anticancer delivery. Synthesis schema of molecular imprinting of methotrexate in biodegradable polymer based on dimethacryloyl hydroxylamine cross-linker, for use as nanocarrier anticancer delivery to breast tumor.

Development of WRAP5 Peptide Complexes for Targeted Drug/Gene Co-Delivery toward Glioblastoma Therapy

Despite the great progress over the past few decades in both the diagnosis and treatment of a great variety of human cancers, glioblastoma remains the most lethal brain tumor. In recent years, cancer gene therapy focused on non-viral vectors which emerged as a promising approach to glioblastoma treatment. Transferrin (Tf) easily penetrates brain cells of the blood–brain barrier, and its receptor is highly expressed in this barrier and glioblastoma cells. Therefore, the development of delivery systems containing Tf appears as a reliable strategy to improve their brain cells targeting ability and cellular uptake. In this work, a cell-penetrating peptide (WRAP5), bearing a Tf-targeting sequence, has been exploited to condense tumor suppressor p53-encoding plasmid DNA (pDNA) for the development of nanocomplexes. To increase the functionality of developed nanocomplexes, the drug Temozolomide (TMZ) was also incorporated into the formulations. The physicochemical properties of peptide/pDNA complexes were revealed to be dependent on the nitrogen to phosphate groups ratio and can be optimized to promote efficient cellular internalization. A confocal microscopy study showed the capacity of developed complexes for efficient glioblastoma cell transfection and consequent pDNA delivery into the nucleus, where efficient gene expression took place, followed by p53 protein production. Of promise, these peptide/pDNA complexes induced a significant decrease in the viability of glioblastoma cells. The set of data reported significantly support further in vitro research to evaluate the therapeutic potential of developed complexes against glioblastoma.

Oncolytic Newcastle Disease Virus Co-Delivered with Modified PLGA Nanoparticles Encapsulating Temozolomide against Glioblastoma Cells: Developing an Effective Treatment Strategy

Glioblastoma multiforme (GBM) is considered to be one of the most serious version of primary malignant tumors. Temozolomide (TMZ), an anti-cancer drug, is the most common chemotherapeutic agent used for patients suffering from GBM. However, due to its inherent instability, short biological half-life, and dose-limiting characteristics, alternatives to TMZ have been sought. In this study, the TMZ-loaded PLGA nanoparticles were prepared by employing the emulsion solvent evaporation technique. The prepared TMZ-PLGA-NPs were characterized using FT-IR, zeta potential analyses, XRD pattern, particle size estimation, TEM, and FE-SEM observations. The virotherapy, being safe, selective, and effective in combating cancer, was employed, and TMZ-PLGA-NPs and oncolytic Newcastle Disease Virus (NDV) were co-administered for the purpose. An AMHA1-attenuated strain of NDV was propagated in chicken embryos, and the virus was titrated in Vero-slammed cells to determine the infective dose. The in vitro cytotoxic effects of the TMZ, NDV, and the TMZ-PLGA-NPs against the human glioblastoma cancer cell line, AMGM5, and the normal cell line of rat embryo fibroblasts (REFs) were evaluated. The synergistic effects of the nano-formulation and viral strain combined therapy was observed on the cell lines in MTT viability assays, together with the Chou–Talalay tests. The outcomes of the in vitro investigation revealed that the drug combinations of NDV and TMZ, as well as NDV and TMZ-PLGA-NPs exerted the synergistic enhancements of the antitumor activity on the AMGM5 cell lines. The effectiveness of both the mono, and combined treatments on the capability of AMGM5 cells to form colonies were also examined with crystal violet dyeing tests. The morphological features, and apoptotic reactions of the treated cells were investigated by utilizing the phase-contrast inverted microscopic examinations, and acridine orange/propidium iodide double-staining tests. Based on the current findings, the potential for the use of TMZ and NDV as part of a combination treatment of GBM is significant, and may work for patients suffering from GBM.

Self-assembled dehydropeptide nanocarrier as a delivery system for antitumor drug temozolomide

Stable molecular conformation and intermolecular forces are essential for peptide self-assembly. In this study, one novel dehydropeptide (DDP) monomer (Boc-(Z)C^α,β-ΔPhe-Gly-NHMe, DDP 1) was prepared; its conformation was confirmed to be more stable than the normal peptide 2 by nuclear magnetic resonance (NMR) and X-ray crystal diffraction experiments. DDP 1 was self-assembled to one novel dehydropeptide nanomaterial (DDPN 1). Fourier transform infrared (FTIR) spectroscopy results showed that hydrogen bonding was the main driving force of self-assembly. Electron microscope images displayed that the DDPN 1 fibers were longer and more stable than peptide 2 nanomaterials. Results of cell activity and enzyme hydrolysis proved that DDPN 1 had excellent biocompatibility and resistance to the enzymatic hydrolysis of protease K. Therefore, the DDPN 1 was used to load the antitumor drug temozolomide (TMZ). Due to intermolecular hydrogen bonds formed between TMZ and DDPN 1, TMZ-loaded DDPN 1 had a high percent entrapment efficiency (EE) of 83.72 ± 4.30% (n = 8) and a percent drug loading efficiency (LE) of 6.70 ± 0.34% (n = 8), and the half-life of TMZ-loaded DDPN 1 was 2.5-3 times longer than that of TMZ at pH 7. The in vitro cell viability results revealed that TMZ-loaded DDPN 1 exhibited higher antitumor activity (IC₅₀ = 552.1 μM) against U118-MG than that of TMZ (IC₅₀ = 1980.1 μM), possibly because that U118-MG cells uptook more TMZ from TMZ-loaded DDPN 1 than from free TMZ directly. This study is expected to inspire the design of biocompatible nanocarriers applied for anti-enzymatic hydrolysis in drug delivery systems.

Long-Term Sustained Drug Delivery via 3D Printed Masks for the Development of a Heparin-Loaded Interlayer in Vascular Tissue Engineering Applications

Current approaches in small-diameter vascular grafts for coronary artery bypass surgeries fail to address physiological variations along the graft that contribute to thrombus formation and ultimately graft failure. We present an innovative interlayer drug delivery system that can be utilized for the sustained delivery of heparin through a graft with a high degree of temporal and spatial control. A heparin-loaded gelatin methacrylate (gelMA) interlayer sits within a biohybrid composed of decellularized bovine pericardium (dECM) and poly(propylene fumarate) (PPF), and its UV crosslinking is controlled via three-dimensional (3D) printed shadow masks. The masks can be readily designed to modulate the incident light intensity on the graft, enabling us to control the resultant gelMA crosslinking and properties. A high heparin loading efficiency was obtained in gelMA and was independent of crosslinking. We achieved sustained heparin release over the course of 2 weeks within the biohybrid material using the 3D printed mask patterns. High doses of heparin were observed to have detrimental effects on endothelial cell function. However, when exposed to heparin in a slower, more sustained manner consistent with the masks, endothelial cells behave similarly to untreated cells. Further, slower release profiles cause significantly more release of tissue factor pathway inhibitor, an anticoagulant, than a faster release profile. The heparin-loaded gelMA interlayer we have developed is a useful tool for the temporal and spatial control of heparin release that supports endothelial function and promotes an antithrombotic environment.

R, Trevino De Leo C, Lopez SA, Martirosyan KS, Chew SA. Application of iron oxide nanoparticles to control the release of minocycline for the treatment of glioblastoma

Background: The utilization of iron oxide nanoparticles (Fe3O4 NPs) to control minocycline release rates from poly(lactic-co-glycolic acid) scaffolds fabricated from an easy/economical technique is presented. Results & methodology: A larger change in temperature and amount of minocycline released was observed for scaffolds with higher amounts of Fe3O4 NPs, demonstrating that nanoparticle concentration can control heat generation and minocycline release. Temperatures near a polymer's glass transition temperature can result in the polymer's chain becoming more mobile and thus increasing drug diffusion out of the scaffold. Elevated temperature and minocycline released from the scaffold can work synergistically to enhance glioblastoma cell death. Conclusion: This study suggests that Fe3O4 NPs are promising materials for controlling minocycline release from polymeric scaffolds by magnetic hyperthermia for the treatment of glioblastoma.

Design, Synthesis, and Biological Evaluation of Dexamethasone-Salvianolic Acid B Conjugates and Nanodrug Delivery against Cisplatin-Induced Hearing Loss

Cisplatin (CDDP) is an extensively used chemotherapeutic agent but has a high incidence of severe ototoxicity. Although a few molecules have entered clinical trials, none have been approved to prevent or treat CDDP-induced hearing loss by the Food and Drug Administration. In this study, an amphiphilic drug-drug conjugate was synthesized by covalently linking dexamethasone (DEX) and salvianolic acid B (SAL) through an ester or amide bond. The conjugates could self-assemble into nanoparticles (NPs) with ultrahigh drug loading capacity and favorable stability. Compared with DEX, SAL, or their physical mixture at the same concentrations, both conjugates and NPs showed enhanced otoprotection in vitro and in vivo. More importantly, the conjugates and NPs almost completely restored hearing in a guinea pig model with good biocompatibility. Immunohistochemical analyses suggested that conjugates and NPs activated the glucocorticoid receptor, which may work as one of the major mechanisms for their protective effects.

Recent advances in the formulation of PLGA microparticles for controlled drug delivery

Polymeric microparticles (MPs) are recognized as very popular carriers to increase the bioavailability and bio-distribution of both lipophilic and hydrophilic drugs. Among different kinds of polymers, poly-(lactic-co-glycolic acid) (PLGA) is one of the most accepted materials for this purpose, because of its biodegradability (due to the presence of ester linkages that are degraded by hydrolysis in aqueous environments) and safety (PLGA is a Food and Drug Administration (FDA)-approved compound). Moreover, its biodegradability depends on the number of glycolide units present in the structure, indeed, lower glycol content results in an increased degradation time and conversely a higher monomer unit number results in a decreased time. Due to this feature, it is possible to design and fabricate MPs with a programmable and time-controlled drug release. Many approaches and procedures can be used to prepare MPs. The chosen fabrication methodology influences size, stability, entrapment efficiency, and MPs release kinetics. For example, lipophilic drugs as chemotherapeutic agents (doxorubicin), anti-inflammatory non-steroidal (indomethacin), and nutraceuticals (curcumin) were successfully encapsulated in MPs prepared by single emulsion technique, while water-soluble compounds, such as aptamer, peptides and proteins, involved the use of double emulsion systems to provide a hydrophilic compartment and prevent molecular degradation. The purpose of this review is to provide an overview about the preparation and characterization of drug-loaded PLGA MPs obtained by single, double emulsion and microfluidic techniques, and their current applications in the pharmaceutical industry.Graphic abstract.