Dietary-Polysaccharide-Modified Fish-Oil-Based Double Emulsion as a Functional Colloidal Formulation for Oral Drug Delivery

Stability of oil-in-water emulsion and immunomodulating activity in S180 tumor-bearing mice

The stability and nutritional integrity of emulsions are susceptible to various factors including thermal treatment, solid-liquid ratio, and sterilization. In this study, the physicochemical stability and immunomodulatory activities of an oil-in-water emulsion containing immune peptides (TUFSE) were assessed through particle size, zeta potential, related cytokines, and so on. When the temperature was 70°C and a solid-liquid ratio of 1:4, the emulsion revealed stability at high-pressure homogenization, with the small particle size. The loss rates of vitamins were 8.57%-62.26% in 6 months at 25°C. After treatment with cyclophosphamide (CTX), lymphocyte proliferation activity in TUFSE-H group increased (p < 0.05), and immune globulin levels were notably elevated (p < 0.05) in TUFSE groups compared to model group. It confirms the parameters of the emulsion, suggesting its ability to be prepared with minimal vitamin loss while simultaneously improving the disease status in CTX-treated tumor-bearing mice. It shows potential as an immune-enhancing supplement with significant potential value. PRACTICAL APPLICATION: This study validated the parameters of the oil-in-water emulsion and showed that it can be stably prepared with minor vitamin loss while simultaneously improving the disease status in CTX-treated tumor-bearing mice. TUFSE-H group exhibited a notable increase in lymphocytes proliferation activity, whereas serum cytokines and immune globulin levels were elevated compared to MC group, indicating its potential as an immune-enhancing supplement with substantial value.

Cryo-Milled β-Glucan Nanoparticles for Oral Drug Delivery

Gemcitabine is a nucleoside analog effective against a number of cancers. However, it has an oral bioavailability of less than 10%, due to its high hydrophilicity and low permeability through the intestinal epithelium. Therefore, the aim of this project was to develop a novel nanoparticulate drug delivery system for the oral delivery of gemcitabine to improve its oral bioavailability. In this study, gemcitabine-loaded β-glucan NPs were fabricated using a film-casting method followed by a freezer-milling technique. As a result, the NPs showed a small particle size of 447.6 ± 14.2 nm, and a high drug entrapment efficiency of 64.3 ± 2.1%. By encapsulating gemcitabine into β-glucan NPs, a sustained drug release profile was obtained, and the anomalous diffusion release mechanism was analyzed, indicating that the drug release was governed by diffusion through the NP matrix as well as matrix erosion. The drug-loaded NPs had a greater ex vivo drug permeation through the porcine intestinal epithelial membrane compared to the plain drug solution. Cytotoxicity studies showed a safety profile of the β-glucan polymers, and the IC50s of drug solution and drug-loaded β-glucan NPs were calculated as 228.8 ± 31.2 ng·mL-1 and 306.1 ± 46.3 ng·mL-1, respectively. Additionally, the LD50 of BALB/c nude mice was determined as 204.17 mg/kg in the acute toxicity studies. Notably, pharmacokinetic studies showed that drug-loaded β-glucan NPs could achieve a 7.4-fold longer T1/2 and a 5.1-fold increase in oral bioavailability compared with plain drug solution. Finally, in vivo pharmacodynamic studies showed the promising capability of gemcitabine-loaded β-glucan NPs to inhibit the 4T1 breast tumor growth, with a 3.04- and 1.74-fold reduction compared to the untreated control and drug solution groups, respectively. In conclusion, the presented freezer-milled β-glucan NP system is a suitable drug delivery method for the oral delivery of gemcitabine and demonstrates a promising potential platform for oral chemotherapy.

Fish oil-based microemulsion can efficiently deliver oral peptide blocking PD-1/PD-L1 and simultaneously induce ferroptosis for cancer immunotherapy

Peptide immune checkpoint inhibitors in cancer immunotherapy have attracted great attention recently, but oral delivery of these peptides remains a huge challenge due to the harsh gastrointestinal environment, large molecular size, high hydrophilic, and poor transmembrane permeability. Here, for the first time, a fish oil-based microemulsion was developed for oral delivery of programmed death-1/programmed cell death-ligand 1 (PD-1/PD-L1) blocking model peptide, OPBP-1. The delivery system was characterized, in vitro and in vivo studies were conducted to evaluate its overall implication. As a result, this nutraceutical microemulsion was easily formed without the need of co-surfactants, and it appeared light yellow, transparent, good flowability with a particle size of 152 ± 0.73 nm, with a sustained drug release manner of 56.45 ± 0.36% over 24 h and a great stability within the harsh intestinal environment. It enhanced intestinal drug uptake and transportation over human intestinal epithelial Caco-2 cells, and drastically elevated the oral peptide bioavailability of 4.1-fold higher than that of OPBP-1 solution. Meanwhile, the mechanism of these dietary droplets permeated over the intestinal enterocytic membrane was found via clathrin and caveolae-mediated endocytic pathways. From the in vivo studies, the microemulsion facilitated the infiltration of CD8+ T lymphocytes in tumors, with increased interferon-γ (IFN-γ) secretion. Thus, it manifested a promising immune anti-tumor effect and significantly inhibited the growth of murine colonic carcinoma (CT26). Furthermore, it was found that the fish oil could induce ferroptosis in tumor cells and exhibited synergistic effect with OPBP-1 for cancer immunotherapy. In conclusion, this fish oil-based formulation demonstrated great potential for oral delivery of peptides with its natural property in reactive oxygen species (ROS)-related ferroptosis of tumor cells, which provides a great platform for functional green oral delivery system in cancer immunotherapy.

The potential, challenges, and prospects of the genus Spirulina polysaccharides as future multipurpose biomacromolecules

Spirulina has been widely used worldwide as a food and medicinal ingredient for centuries. Polysaccharides are major bioactive constituents of Spirulina and are of interest because of their functional properties and unlimited application potential. However, the clinical translation and market industrialization of the polysaccharides from genus Spirulina (PGS) are retarded due to the lack of a further understanding of their isolation, bioactivities, structure-activity relationships (SARs), toxicity, and, most importantly, versatile applications. Herein, we provide an overview of the extraction, purification, and structural features of PGS; meanwhile, the advances in bioactivities, SARs, mechanisms of effects, and toxicity are discussed and summarized. Furthermore, the applications, potential developments, and future research directions are scrutinized and highlighted. This review may help fill the knowledge gap between theoretical insights and practical applications and guide future research and industrial application of PGS.