Formulation optimization of solid self-microemulsifying pellets for enhanced oral bioavailability of curcumin

Exploring novel type of lipid-bases drug delivery systems that contain one lipid and one water-soluble surfactant only

None of transitional lipid-based drug delivery systems (LBDDS) includes compositions containing one lipid and one water-soluble surfactant that form stable microemulsions. The conversion of liquid LBDDS to solid LBDDS has been limited by low drug loading. Previously, we have developed drug solid microemulsions containing one lipid and TPGS (a water-soluble surfactant) that achieved high drug loading and remarkably increased oral bioavailability. This study aimed to test if binary lipid systems (BLS), composed of one lipid and one water-soluble surfactant that form stable self-emulsifying microemulsions, is not an exclusive but widely applicable type of LBDDS for other lipids and surfactants and evaluate the influences of chemical structures of lipids and surfactants on microemulsions and solid microemulsions. We systemically identified new BLS by using a library of lipids and surfactants. Propylene glycol diesters and glycerol triesters were favorable for forming stable microemulsions with Tween 80, Cremophor EL, or TPGS. To the best of our knowledge, this is the first report exploring and confirming that the BLS is a new addition to traditional LBDDS, provides a promising option for researchers, and has the potential to increase drug loading to facilitate the development of solid microemulsions.

Defining the mechanisms behind the hepatoprotective properties of curcumin

As a critical cause of human dysfunctionality, hepatic failure leads to approximately two million deaths per year and is on the rise. Considering multiple inflammatory, oxidative, and apoptotic mechanisms behind hepatotoxicity, it urges the need for finding novel multi-targeting agents. Curcumin is a phenolic compound with anti-inflammatory, antioxidant, and anti-apoptotic roles. Curcumin possesses auspicious health benefits and protects against several diseases with exceptional safety and tolerability. This review focused on the hepatoprotective mechanisms of curcumin. The need to develop novel delivery systems of curcumin (e.g., nanoparticles, self-micro emulsifying, lipid-based colloids, solid lipid nanoparticles, cyclodextrin inclusion, phospholipid complexes, and nanoemulsions) is also considered.

Regulation of immunomodulatory networks by Nrf2-activation in immune cells: Redox control and therapeutic potential in inflammatory diseases

Inflammatory diseases present a serious health challenge due to their widespread prevalence and the severe impact on patients' lives. In the quest to alleviate the burden of these diseases, nuclear factor erythroid 2-related factor 2 (Nrf2) has emerged as a pivotal player. As a transcription factor intimately involved in cellular defense against metabolic and oxidative stress, Nrf2's role in modulating the inflammatory responses of immune cells has garnered significant attention. Recent findings suggest that Nrf2's ability to alter the redox status of cells underlies its regulatory effects on immune responses. Our review delves into preclinical and clinical evidence that underscores the complex influence of Nrf2 activators on immune cell phenotypes, particularly in the inflammatory milieu. By offering a detailed analysis of Nrf2's role in different immune cell populations, we cast light on the potential of Nrf2 activators in shaping the immune response towards a more regulated state, mitigating the adverse effects of inflammation through modeling redox status of immune cells. Furthermore, we explore the innovative use of nanoencapsulation techniques that enhance the delivery and efficacy of Nrf2 activators, potentially advancing the treatment strategies for inflammatory ailments. We hope this review will stimulate the development and expansion of Nrf2-targeted treatments that could substantially improve outcomes for patients suffering from a broad range of inflammatory diseases.

Protein-polysaccharide-based delivery systems for enhancing the bioavailability of curcumin: A review

In recent years, a wide attention has been paid to curcumin in medicine due to its excellent physiological activities, including anti-inflammatory, antioxidant, antibacterial, and nerve damage repair. However, the low solubility, poor stability, and rapid metabolism of curcumin make its bioavailability low, which affects its development and application. As a unique biopolymer structure, protein-polysaccharide (PRO-POL)-based delivery system has the advantages of low toxicity, biocompatibility, biodegradability, and delayed release. Many scholars have investigated PRO-POL -based delivery systems to improve the bioavailability of curcumin. In this paper, we focus on the interactions between different proteins (e.g. casein, whey protein, soybean protein isolate, pea protein, zein, etc.) and polysaccharides (chitosan, sodium alginate, hyaluronic acid, pectin, etc.) and their effects on complexes diameter, surface charge, encapsulation drive, and release characteristics. The mechanism of the PRO-POL-based delivery system to enhance the bioavailability of curcumin is highlighted. In addition, the application of PRO-POL complexes loaded with curcumin is summarized, aiming to provide a reference for the construction and application of PRO-POL delivery systems.

Cinnamon oil solid self-microemulsion mediates chronic mild stress-induced depression in mice by modulating monoamine neurotransmitters, corticosterone, inflammation cytokines, and intestinal flora

Cinnamon oil (CO) is a classic Chinese medicine with excellent soothing effects on exhaustion, weakness and depression. Cinnamaldehyde is the main active ingredient of cinnamic oil. Although CO have antidepression-like effects, limited information is available. Furthermore, the disadvantages of CO, such as low oral availability and difficult portability, limit its development. In this study, a Cinnamon Oil Solid Self-Microemulsifying Drug Delivery System (CO-S-SME) was designed, prepared. In addition, we explored the effects and mechanisms of CO-S-SME on chronic unpredictable mild stress (CUMS)-induced depression-like behavior, monoamine neurotransmitters, inflammatory factors, intestinal flora in mice. Mice were subjected CUMS to establish the depression model. The antidepressant effect of CO-S-SME was evaluated by behavioral tests. In addition, the expression levels of neurotransmitters, corticosterone (CORT) and inflammatory factors in CUMS mice were analyzed by enzyme-linked immunosorbent assay. In addition, we explored the effects of CO-S-SME on the diversity and richness of intestinal flora of mice in each group. Behavioral tests showed that CO-S-SME could effectively improve depression-like behaviors in CUMS mice. Specifically, CO-S-SME treatment effectively increased neurotransmitter levels and reduced the expressions of corticosterone and inflammatory factors in CUMS mice. CO-S-SME also changed the intestinal flora composition, decreased the ratio of Firmicutes to Bacteroidetes, reduced relative abundances of Lactobacillus, modulated Alpha diversity and beta diversity. These results suggest that CO-S-SME an act as a good antidepressant, exhibiting effects via monoamine neurotransmitters, CORT, inflammation cytokines, and intestinal flora.

A review on curcumin colon-targeted oral drug delivery systems for the treatment of inflammatory bowel disease

Synthetic drugs and monoclonal antibodies are the typical treatments to combat inflammatory bowel disease (IBD). However, side effects are present when these treatments are used, and their continued application could be restricted by the high relapse rate of the disease. One potential alternative to these treatments is the use of plant-derived products. The use curcumin is one such treatment option that has seen an increase in usage in treating IBD. Curcumin is derived from a rhizome of turmeric (Curcuma longa), and the results of studies on the use of curcumin to treat IBD are promising. These studies suggest that curcumin interacts with cellular targets such as NF-κB, JAKs/STATs, MAPKs, TNF-α, IL-6, PPAR, and TRPV1 and may reduce the progression of IBD. Potentially, curcumin can be used as a therapeutic agent for patients with IBD when it reduces the incidence of clinical relapse. This review discusses the strategies utilized in designing and developing an oral colonic delivery dosage form of curcumin.

Characterization and Ex vivo Evaluation of Curcumin Nanoethosomes for Melanoma treatment

This study aimed at developing curcumin nanoethosomes (Cur-Ets) with superior skin permeation intended for melanoma treatment. Although curcumin is active against many types of skin cancers, a suitable topical formulation is still lacking due to its hydrophobicity and poor skin permeation. The formulation was characterized using Scanning Transmission Electron Microscopy (STEM), atomic force microscopy (AFM), ATR-FTIR, DSC, and XRD. In vitro skin permeation was carried out using human skin, and the cytotoxicity of the formulation was evaluated on human melanoma cells (SK-MEL28). The vesicle size and zeta potential of the Cur-Ets were determined as 67 ± 1.6 nm and - 87.3 ± 3.3 mV, respectively. STEM and AFM analysis further support the size and morphology of the formulation. Curcumin's compatibility with formulation additives was confirmed by ATR-FTIR analysis. In addition, DSC and XRD analyses showed successful drug encapsulation in nanoethosomes. The drug encapsulation efficiency was determined as 87 ± 0.9%. The skin permeation of curcumin from Cur-Ets showed a superior flux (0.14 ± 0.03 µg cm^-2 h^-1) compared to the control (p < 0.05). Cytotoxicity of the formulation demonstrated a time-dependent and concentration-dependent antiproliferative activity against melanoma cells. The developed Cur-Ets is suggested as a promising topical formulation for melanoma treatment.

Drug Delivery Strategies for Curcumin and Other Natural Nrf2 Modulators of Oxidative Stress-Related Diseases

Oxidative stress is associated with a wide range of diseases characterised by oxidant-mediated disturbances of various signalling pathways and cellular damage. The only effective strategy for the prevention of cellular damage is to limit the production of oxidants and support their efficient removal. The implication of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the cellular redox status has spurred new interest in the use of its natural modulators (e.g., curcumin, resveratrol). Unfortunately, most natural Nrf2 modulators are poorly soluble and show extensive pre-systemic metabolism, low oral bioavailability, and rapid elimination, which necessitates formulation strategies to circumvent these limitations. This paper provides a brief introduction on the cellular and molecular mechanisms involved in Nrf2 modulation and an overview of commonly studied formulations for the improvement of oral bioavailability and in vivo pharmacokinetics of Nrf2 modulators. Some formulations that have also been studied in vivo are discussed, including solid dispersions, self-microemulsifying drug delivery systems, and nanotechnology approaches, such as polymeric and solid lipid nanoparticles, nanocrystals, and micelles. Lastly, brief considerations of nano drug delivery systems for the delivery of Nrf2 modulators to the brain, are provided. The literature reviewed shows that the formulations discussed can provide various improvements to the bioavailability and pharmacokinetics of natural Nrf2 modulators. This has been demonstrated in animal models and clinical studies, thereby increasing the potential for the translation of natural Nrf2 modulators into clinical practice.