This study aims to design a pH-responsive dual-loaded nanosystem based on PEGylated chitosan nanoparticles loaded with ascorbic acid (AA) and oxaliplatin (OX) for the effective treatment of breast cancer. In this regard, non-PEGylated and PEGylated chitosan nanoparticles (CS NPs) loaded with either ascorbic acid (AA), oxaliplatin (OX), or dual-loaded with AA-OX were fabricated using the ionotropic gelation method. The hydrodynamic diameters of the fabricated AA/CS NPs, OX/CS NPs, and AA-OX/CS NPs were 157.20 ± 2.40, 188.10 ± 9.70, and 261.10 ± 9.19 nm, respectively. While the hydrodynamic diameters of the designed AA/PEG-CS NPs, OX/PEG-CS NPs, and AA-OX/PEG-CS NPs were 152.20 ± 2.40, 156.60 ± 4.82, and 176.00 ± 4.21 nm, respectively. The ζ-potential of the prepared nanoparticles demonstrated high positive surface charges of +22.02 ± 1.50, +22.58 ± 1.85 and +40.4 ± 2.71 mV for AA/CS NPs, OX/CS NPs, and AA-OX/CS NPs, respectively. The ζ-potential of the PEGylated CS NPs was reduced owing to the shielding of the positive charges by the PEG chains. Additionally, all the prepared nanoparticles exhibited high entrapment efficiencies (EE%) and spherical-shaped morphology. The chemical features of the prepared nanoparticles were investigated using Fourier transform infrared (FTIR) spectroscopy. Release studies showed the capability of the prepared non-PEGylated and PEGylated chitosan NPs to release their cargo in the acidic environment of cancer tissue (pH 5.5). Furthermore, the AA/CS NPs, AA/PEG-CS NPs, OX/CS NPs, OX/PEG-CS NPs, AA-OX/CS NPs and AA-OX/PEG-CS NPs exhibited remarkable cytotoxic activities against breast adenocarcinoma (MCF-7) cells with IC50 values of 44.87 ± 11.49, 23.3 ± 3.73, 23.88 ± 6.29, 17.98 ± 3.99, 18.69 ± 2.22, and 7.5 ± 0.69 µg/mL, respectively; as compared to free AA and OX (IC50 of 150.80 ± 26.50 and 147.70 ± 63.91 µg/mL, respectively). Additionally, treatment of MCF-7 cells with IC50 concentrations of AA, AA/CS NPs, AA/PEG-CS NPs, OX, OX/CS NPs, OX/PEG-CS NPs, AA-OX/CS NPs or AA-OX/PEG-CS NPs increased the percentages of early apoptotic cells to 5.28%, 9.53%, 11.20%, 5.27%, 13.80%, 8.43%, 2.32%, and 10.10%, respectively, and increased the percentages of late apoptotic cells to 0.98%, 0.37%, 2.41%, 2.06%, 0.97%, 9.66%, 56%, and 81.50%, respectively. These results clearly indicate that PEGylation enhances the apoptotic effect of AA and OX alone, in addition to potentiating the apoptotic effect of AA and OX when combined on MCF-7 cells. In conclusion, PEGylated chitosan nanoparticles encapsulating AA, OX, or AA and OX represent an effective formula for induction of apoptosis in MCF-7 cells.

Para-sulfocalix[n]arenes are promising host molecules that can accommodate various chemotherapeutic drugs. Pt(IV)-based complexes, including satraplatin and asplatin, are promising alternatives that overcome the shortcomings of Pt(II) complexes. In this study, asplatin has been synthesized by fusing acetylsalicylic acid (aspirin) and cisplatin. Furthermore, it has been characterized using 1H NMR, mass spectrometry, elemental analysis, and UHPLC. A host-guest complex of asplatin and p-sulfocalix[4]arene (PSC4) has been developed and characterized using UV, Job’s plot analysis, HPLC, and density functional theory (DFT) calculations. The experimental and computational investigations propose that a 1:1 complex between asplatin and PSC4 is formed. The stability constant of the designed complex has been determined using Job’s plot and UHPLC and computed to be 9.1 × 104 M–1 and 8.7 × 104 M−1, which corresponds to a free energy of complexation of −6.8 kcal mol–1, while the calculated value for the inclusion free energy is −13.2 kcal mol−1. Both experimentally and theoretically estimated complexation free energy show that a stable host-guest complex can be formed in solution. The in vitro drug release study displayed the ability of the complex to release its cargo at a cancerous pH (pH of 5.5). Additionally, the asplatin/PSC4 complex is shown to be biocompatible when tested on human skin fibroblast noncancerous cells, demonstrating the highest in vitro cytotoxic activity against (MCF-7), cervical (HeLa), and lung cancer cells (A-549), with IC50 values of 0.75, 2.15, and 3.60 µg/mL, respectively. This is as compared to either cisplatin (IC50 of 5.47, 5.94 and 9.61 µg/mL, respectively) or asplatin (IC50 of 1.54, 5.05 and 3.91 µg/mL, respectively). On the other hand, the free asplatin exhibited higher cytotoxicity on cancerous cells and lower toxicity on noncancerous cells. The outcomes of the present joint theoretical and experimental investigation reinforce the interest in platinum-based anticancer therapeutics when they are protected from undesired interactions and suggest the use of the PSC4 macromolecule as a promising carrier for Pt(IV) anticancer drugs. The formed asplatin/PSC4 inclusion complex may represent an effective chemotherapeutic agent.

The potential of computational models to identify new therapeutics and repurpose existing drugs has gained significance in recent times. The current ‘COVID-19′ pandemic caused by the new SARS CoV2 virus has affected over 200 million people and caused over 4 million deaths. The enormity and the consequences of this viral infection have fueled the research community to identify drugs or vaccines through a relatively expeditious process. The availability of high-throughput datasets has cultivated new strategies for drug development and can provide the foundation towards effective therapy options. Molecular modeling methods using structure-based or computer-aided virtual screening can potentially be employed as research guides to identify novel antiviral agents. This review focuses on in-silico modeling of the potential therapeutic candidates against SARS CoVs, in addition to strategies for vaccine design. Here, we particularly focus on the recently published SARS CoV main protease (Mpro) active site, the RNA-dependent RNA polymerase (RdRp) of SARS CoV2, and the spike S-protein as potential targets for vaccine development. This review can offer future perspectives for further research and the development of COVID-19 therapies via the design of new drug candidates and multi-epitopic vaccines and through the repurposing of either approved drugs or drugs under clinical trial.

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