Evaluation of heteroscorpionate ligands as scaffolds for the generation of Ruthenium(II) metallodrugs in breast cancer therapy.

The modular synthesis of the heteroscorpionate core is explored as a tool for the rapid development of ruthenium-based therapeutic agents. Starting with a series of structurally diverse alcohol-NN ligands, a family of heteroscorpionate-based ruthenium derivatives was synthesized, characterized, and evaluated as an alternative to platinum therapy for breast cancer therapy. In vitro, the antitumoral activity of the novel derivatives was assessed in a series of breast cancer cell lines using UNICAM-1 and cisplatin as metallodrug control. Through this approach, a bimetallic heteroscorpionate-based metallodrug (RUSCO-2) was identified as the lead compound of the series with an IC50 value range as low as 3-5 µM. Notably, RUSCO-2 was found to be highly cytotoxic in TNBC cell lines, suggesting a mode of action independent of the receptor status of the cells. As a proof of concept and taking advantage of the luminescent properties of one of the complexes obtained, uptake was monitored in human breast cancer MCF7 cell lines by fluorescence lifetime imaging microscopy (FLIM) to reveal that the compound is evenly distributed in the cytoplasm and that the incorporation of the heteroscorpionate ligand protects it from aqueous processes, conversion in another entity, or the loss of the chloride group. Finally, ROS studies were conducted, lipophilicity was estimated, the chloride/water exchange was studied, and stability studies in simulated biological media were carried out to propose structure-activity relationships.

Quantitative considerations about the size dependence of cellular entry and excretion of colloidal nanoparticles for different cell types.

Most studies about the interaction of nanoparticles (NPs) with cells have focused on how the physicochemical properties of NPs will influence their uptake by cells. However, much less is known about their potential excretion from cells. However, to control and manipulate the number of NPs in a cell, both cellular uptake and excretion must be studied quantitatively. Monitoring the intracellular and extracellular amount of NPs over time (after residual noninternalized NPs have been removed) enables one to disentangle the influences of cell proliferation and exocytosis, the major pathways for the reduction of NPs per cell. Proliferation depends on the type of cells, while exocytosis depends in addition on properties of the NPs, such as their size. Examples are given herein on the role of these two different processes for different cells and NPs.

Formulation, Optimization and In vitro / In vivo Characterization of Spray Dried Doxorubicin Loaded Folic Acid Conjugated Gelatin Nanoparticles.

AIM: Formulation, optimization and anticancer activity of spray-dried Doxorubicin loaded folic acid conjugated Gelatin nanoparticles (DOX-FA-GN). METHODS: Doxorubicin loaded gelatin nanoparticles (DOX-GN) were prepared by the Coacervation phase separation method, optimized using DoE and then conjugated with folic acid by covalent coupling to formulate Doxorubicin loaded folic acid conjugated nanoparticles (DOX-FA-GN). The formulated nanoparticles were characterized to evaluate its physicochemical properties. Cellular uptake and cell viability studies were carried out using MTT assay and biodistribution studies were carried out in Wistar rats. RESULTS: Particle size, PDI and entrapment efficiency for optimized DOX-GN were found to be 152.3 ± 9.3 nm 0.294 ± 0.1 and 86.9± 3.4% while for DOX-FA-GN, 193.9 ± 12.3 nm 0.247 ± 0.2 and 84 ± 3.6%. The cytotoxic studies showed a cell viability of 75.1% for DOX-GN and 29.5% DOX-FA-GN. Biodistribution studies were found to be statistically insignificant for conjugated nanoparticles with excellent flow properties. Significantly higher DOX distribution in the lungs was observed in the case of DOX-FA-GN. CONCLUSION: There was a higher uptake of DOX on HeLa cells with DOX-FA-GN compared to DOX-GN. Also, the biodistribution of Dox in the lungs of Wistar rats was higher in conjugated nanoparticles as compared to unconjugated nanoparticles.

Atorvastatin-loaded solid lipid nanoparticles as eye drops: proposed treatment option for age-related macular degeneration (AMD).

Statins, widely prescribed for cardiovascular diseases, are also being eyed for management of age-related macular degeneration (AMD). Poor bioavailability and blood-aqueous barrier may however limit significant ocular concentration of statins following oral administration. We for the first time propose and investigate local application of atorvastatin (ATS; representative statin) loaded into solid lipid nanoparticles (SLNs), as self-administrable eye drops. Insolubility, instability, and high molecular weight > 500 of ATS, and ensuring that SLNs reach posterior eye were the challenges to be met. ATS-SLNs, developed (2339/DEL/2014) using suitable components, quality-by-design (QBD) approach, and scalable hot high-pressure homogenization, were characterized and evaluated comprehensively for ocular suitability. ATS-SLNs were 8 and 12 times more bioavailable (AUC) in aqueous and vitreous humor, respectively, than free ATS. Three-tier (in vitro, ex vivo, and in vivo) ocular safety, higher corneal flux (2.5-fold), and improved stability (13.62 times) including photostability of ATS on incorporation in ATS-SLNs were established. Autoclavability and aqueous nature are the other highlights of ATS-SLNs. Presence of intact fluorescein-labeled SLNs (F-SLNs) in internal eye tissues post-in vivo application as eye drops provides direct evidence of successful delivery. Perinuclear fluorescence in ARPE-19 cells confirms the effective uptake of F-SLNs. Prolonged residence, up to 7 h, was attributed to the mucus-penetrating nature of ATS-SLNs. Graphical abstract.

Synthesis and evaluation of pH-sensitive, self-assembled chitosan-based nanoparticles as efficient doxorubicin carriers.

A novel pH-responsive polymer based on amphiphilic N-acetyl histidine and arginine-grafted chitosan was synthesized using N-acetyl histidine as hydrophobic segment and arginine as hydrophilic segment by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-mediated coupling reactions as anticancer drug delivery system for doxorubicin. The structure of the synthesized polymer was confirmed by Fourier transform infrared and 1H nuclear magnetic resonance analysis. Due to self-association behavior, N-acetyl histidine and arginine-grafted chitosan structured nanoparticles with in size range of 204 nm. N-acetyl histidine and arginine-grafted chitosan with different substitution degree of N-acetyl histidine were initially prepared and characterized. The critical micelle concentration decreased with increasing substitution degree of N-acetyl histidine. Furthermore, N-acetyl histidine and arginine-grafted chitosan nanoparticles exhibited an acidic pH-triggered aggregation and disassembling nature. The doxorubicin-encapsulated nanoparticles based on synthesized conjugate ( N-acetyl histidine and arginine-grafted chitosan/doxorubicin nanoparticles) showed a sustained drug release pattern, which could be hastened under acidic pH conditions but delayed with increasing substitution degree of N-acetyl histidine. Anticancer effects demonstrated that N-acetyl histidine and arginine-grafted chitosan/doxorubicin nanoparticles could suppress both sensitive and resistant human breast tumor cell line (MCF-7) efficiently in a dose- and time-dependent pattern. Confocal microscopy results evidenced increased cellular uptake and enhanced retention of the synthesized nanoparticles in drug-resistant cells demonstrating better efficacy of nanoparticles over native doxorubicin. These results suggest that N-acetyl histidine and arginine-grafted chitosan/doxorubicin nanoparticles might be promising carriers for delivery of hydrophobic drug doxorubicin against drug-resistant tumors.

Self-assembled nanoparticles based on amphiphilic chitosan derivative and arginine for oral curcumin delivery.

Curcumin (Cur) is a striking anticancer agent, but its low aqueous solubility, poor absorption, hasty metabolism, and elimination limit its oral bioavailability and consequently hinder its development as a drug. To redress these limitations, amphiphilic chitosan (CS) conjugate with improved mucoadhesion and solubility over a wider pH range was developed by modification with hydrophobic acrylonitrile (AN) and hydrophilic arginine (Arg); the synthesized conjugate (AN-CS-Arg), which was well characterized by Fourier transform infrared and 1H nuclear magnetic resonance spectroscopy. Results of critical aggregation concentration revealed that the AN-CS-Arg conjugate had low critical aggregation concentration and was prone to form self-assembled nanoparticles (NPs) in aqueous medium. Cur-encapsulated AN-CS-Arg NPs (AN-CS-Arg/Cur NPs) were developed by a simple sonication method and characterized for the physicochemical parameters such as zeta potential, particle size, and drug encapsulation. The results showed that zeta potential of the prepared NPs was 40.1±2.81 mV and the average size was ~218 nm. A considerable improvement in the aqueous solubility of Cur was observed after encapsulation into AN-CS-Arg/Cur NPs. With the increase in Cur concentration, loading efficiency increased but encapsulation efficiency decreased. The in vitro release profile exhibited sustained release pattern from the AN-CS-Arg/Cur NPs in typical biological buffers. The ex vivo mucoadhesion study revealed that AN-CS-Arg/Cur NPs had greater mucoadhesion than the control CS NPs. Compared with free Cur solution, AN-CS-Arg/Cur NPs showed stronger dose-dependent cytotoxicity against HT-29 cells. In addition, it was observed that cell uptake of AN-CS-Arg/Cur NPs was much higher compared with free Cur. Furthermore, the in vivo pharmacokinetic results in rats demonstrated that the AN-CS-Arg/Cur NPs could remarkably improve the oral bioavailability of Cur. Therefore, the developed AN-CS-Arg/Cur NPs might be a promising nano-candidate for oral delivery of Cur.