Current challenges ahead in preparation, characterization, and pharmaceutical applications of nanoemulsions.

Nanoemulsions (NEs) are emulsions with particle size of less than around 100 nm. Reviewing the literature, several reports are available on NEs, including preparation, characterization, and applications of them. This review aims to brief challenges that researchers or formulators may encounter when working with NEs. For instance, when selecting NE components and identifying their concentrations, stability and safety of the preparation should be evaluated. When preparing an NE, issues over scale-up of the preparation as well as possible effects of the preparation process on the active ingredient need to be considered. When characterizing the NEs, the two major concerns are accuracy of the method and accessibility of the characterizing instrument. Also a highly efficient NE for clinical use to deliver the active ingredient to the target tissue with maximum safety profile is commonly sought. Throughout the review we also have tried to suggest approaches to overcome the challenges. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Cell-based wound dressing: Bilayered PCL/gelatin nanofibers-alginate/collagen hydrogel scaffold loaded with mesenchymal stem cells.

Wound dressing is applied to promote the healing process, wound protection, and additionally regeneration of injured skin. In this study, a bilayer scaffold composed of a hydrogel and nanofibers was fabricated to improve the regeneration of injured skin. To this end, polycaprolactone/gelatin (PCL/Gel) nanofibers were electrospun directly on the prepared collagen/alginate (Col/Alg) hydrogel. The bilayer scaffold was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), mechanical properties, and swelling/degradation time. Cytotoxicity assays were evaluated using MTT assay. Then, the nanofiber and bilayer scaffolds were seeded with Adipose-derived stem cells (ADSCs). ADSCs were isolated from rat adipose tissue and analyzed using flow cytometry, in advance. Full-thickness wounds on the backs of rats were dressed with ADSCs-seeded bilayer scaffolds and nanofibers. Histopathological evaluations were performed after 14 and 21 days using H&E (hematoxylin and eosin) staining. The results indicated that re-epithelialization, angiogenesis, and collagen remodeling were enhanced in ADSCs-seeded bilayer scaffolds and nanofibers in comparison with the control group. In conclusion, the best re-epithelialization, collagen organization, neovascularization, and low presence of inflammation in the wound area were observed in the ADSCs-seeded bilayer scaffolds.

Encapsulation of Ginger Extract in Nanoemulsions: Preparation, Characterization and in vivo Evaluation in Rheumatoid Arthritis.

Ginger is an anti-inflammatory and antioxidant natural substance, however, its effectiveness is limited primarily due to insufficient solubility and low oral bioavailability. This study aimed to formulate ginger extract into nanoemulsion (NE) to enhance therapeutic benefits against rheumatoid arthritis (RA). Hence, ginger extract-loaded NEs were prepared by the spontaneous emulsification method. The NE that passed the thermodynamic stability analyses showed no phase changes or appearance of turbidity. They had an average droplet diameter of 76 ± 45 nm with a zeta potential of - 35 ± 12 mV. Besides, the high antioxidant activities (IC50 = 53.89 µg/mL), about ten times increment of the skin permeability, and no sign of skin irritancy were observed from the ginger-loaded NE. The anti-arthritic evaluations of RA-induced rats treated with ginger-loaded NE showed a significant decline in arthritic symptoms and the highest rate of paw edema inhibition (27.7 %). In addition, the level of involved inflammatory cytokines in the serum of rats was significantly reduced (p < 0.05) compared to the negative control, so that histopathological manifestations also approved the reduction of inflammation indications. Thus, the topical delivery of ginger-loaded NE can be an efficient approach for reducing inflammation and inhibit of RA symptoms.

Antioxidative, anticancer, and antibacterial activities of a nanogel containing Mentha spicata L. essential oil and electrospun nanofibers of polycaprolactone-hydroxypropyl methylcellulose.

BACKGROUND: As the largest organ, the skin has been frequently affected by trauma, chemical materials, toxins, bacterial pathogens, and free radicals. Recently, many attempts have been made to develop natural nanogels that, besides hydrating the skin, could also be used as antioxidant or antibacterial agents. METHODS: In this study, the chemical composition of the Mentha spicata essential oil was first investigated using GC-MS analysis. Its nanoemulsion-based nanogel was then investigated; successful loading of the essential oil in the nanogel was confirmed using FTIR analysis. Besides, nanogel's antioxidative, anticancer, and antibacterial activities were investigated. RESULTS: Carvone (37.1%), limonene (28.5%), borneol (3.9%), ß-pinene (3.3%), and pulegone (3.3%) were identified as five major compounds in the essential oil. By adding carboxymethylcellulose (3.5% w/v) to the optimal nanoemulsion containing the essential oil (droplet size of 196 ± 8 nm), it was gelified. The viscosity was fully fitted with a common non-Newtonian viscosity regression, the Carreau-Yasuda model. The antioxidant effect of the nanogel was significantly more potent than the essential oil (P < 0.001) at all examined concentrations (62.5-1000 µg/mL). Furthermore, the potency of the nanogel with an IC50 value of 55.0 µg/mL was substantially more (P < 0.001) than the essential oil (997.4 µg/mL). Also, the growth of Staphylococcus aureus and Escherichia coli after treatment with 1000 µg/mL nanogel was about 50% decreased compared to the control group. Besides, the prepared electrospun polycaprolactone-hydroxypropyl methylcellulose nanofibers mat with no cytotoxic, antioxidant, or antibacterial effects was proposed as lesion dressing after treatment with the nanogel. High potency, natural ingredients, and straightforward preparation are advantages of the prepared nanogel. Therefore, it could be considered for further consideration in vivo studies.

Subcutaneous Injection of Bee Venom in Wistar Rats: effects on blood cells and biochemical parameters.

Objectives: Bee venom (BV) therapy is performed by a bee sting or subcutaneous injection of BV. However, there is not much information on the effect of BV on blood parameters after entering the body. This project aimed to assess the side effects of subcutaneous BV injections in healthy rats by measuring the hematological and biochemical parameters. Methods: Various amounts of BV, including 100, 200, and 500 (µg/day), were subcutaneously injected into rats for 30 days. The results showed that BV affected the metabolism of the liver, kidney, and glands. Results: An increase in blood sugar and a decrease in other biochemical parameters, including cholesterol, triglyceride, urea, creatinine AST, ALT, ALP, and phosphorous, were observed. Results also showed increased counts of white blood cells, neutrophils (%), and platelets and decreased levels of red cells, hemoglobin, and hematocrit. Conclusion: This study demonstrates that BV therapy in medical clinics requires routine care and testing to prevent eventual metabolic and anemia side effects.

Anti-inflammatory and anti-nociceptive effects of Cinnamon and Clove essential oils nanogels: an in vivo study.

BACKGROUND: Cinnamon (Cinnamomum zeylanicum) and Clove (Syzygium aromaticum) essential oils are two medicinally important plant-derived substances with a wide range of biological properties. Besides, nanoemulsion-based gels have been widely used to increase topical drug delivery and effectiveness. METHODS: This study aimed to explore the anti-inflammatory effect (paw edema test) and the anti-nociceptive effect (hot plate and formalin test) of nanoemulsion-based gels containing the essential oils in the animal model. Cinnamon and Clove essential oils nanoemulsions with droplet sizes of 28 ± 6 nm and 12 ± 3 nm were first prepared. By adding carboxymethylcellulose (3.5% w/v), the nanoemulsions were then gelified. Finally, the nanogels were characterized by ATR-FTIR analysis and were used as topical pre-treatment before induction of inflammation or pain in acute and chronic analgesic experimental studies. RESULTS: The paw edema and formalin findings showed that the nanogels formulations possess significant anti-nociceptive and anti-inflammatory effects. CONCLUSION: The prepared nanogels could be considered as analgesic drugs for inhibiting the inflammation and pain of diseases.

Anti-rheumatic activity of topical nanoemulsion containing bee venom in rats.

PURPOSE: Bee Venom (BV) has been used to treat rheumatoid arthritis (RA) for many centuries. However, its clinical use is limited by pain and fear of bee stings/injection. Nanoemulsions (NEs) are nanocarriers that are able to help their content(s) penetrate through the skin. They also act as drug reservoirs on the skin to provide an efficient, sustained-release vehicle. METHODS: In this paper, we present the development of a stable water-in-oil NE to help passing BV through the animal skin when used topically. RESULTS: Particle size of NE was 12.7 to 29.8 nm for NEs containing 0 to 150 µg/ml BV. Also, its anti-inflammatory effects were evaluated in rat models of type II collagen-induced arthritis. Topical administration of NEs containing 18.75 or 9.37 µg/ml BV were able to significantly (p < 0.05) reduce inflammation in the rat paws compared to the blank and control groups. CONCLUSION: Our findings demonstrated the efficacy of NEs containing BV to reduce inflammation caused by RA animal model.

Hybrid PCL/chitosan-PEO nanofibrous scaffolds incorporated with A. euchroma extract for skin tissue engineering application.

Skin tissue engineering is an advanced method to repair and regenerate skin injuries. Recent research is focused on the development of scaffolds that are safe, bioactive, and cytocompatible. In this work, a new hybrid nanofibrous scaffold composed of polycaprolactone/chitosan-polyethylene oxide (PCL/Cs-PEO) incorporated with Arnebia euchroma (A. euchroma) extract were synthesized by the two-nozzle electrospinning method. Then the synthesized scaffold was characterized for morphology, sustainability, chemical structure and properties. Moreover, to verify their potential in the burn wound healing process, biodegradation rate, contact angle, swelling properties, water vapor permeability, mechanical properties, antibacterial activity and drug release profile were measured. Furthermore, cytotoxicity and biocompatibility tests were performed on human dermal fibroblasts cell line via XTT and LDH assay. It is shown that the scaffold improved and increased proliferation during in-vitro studies. Thus, results confirm the efficacy and potential of the hybrid nanofibrous scaffold for skin tissue engineering.

Serum Levels of IL-6, IL-8, TNF-α, and TGF-ß in Chronic HBV-Infected Patients: Effect of Depression and Anxiety.

OBJECTIVE: To assess the effects of depression and anxiety on serum cytokine levels in patients with chronic hepatitis B (CHB) infection. METHODS: In this cross-sectional study, 60 healthy control individuals and 60 patients with CHB participated after filling out standard questionnaires. We examined their serum interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, and TGF-ß levels using enzyme-linked immunosorbent assay (ELISA) techniques. RESULTS: In patients with CHB compared with healthy controls, serum levels of IL-8 were significantly increased, whereas IL-6 and TGF-ß levels were significantly decreased. Serum levels of TGF-ß were significantly decreased in the patients with CHB who had mild depression, compared with patients with CHB without depression and with moderate and severe depression. CONCLUSIONS: Downregulation of IL-8 and TGF-ß, respectively, is a corresponding mechanism for induction of chronic inflammation in patients with CHB. Depression also seems to induce inflammation via downregulation of TGF-ß in these patients.

Are RIG-1 and MDA5 Expressions Associated with Chronic HBV Infection?

Melanoma differentiation-associated protein 5 (MDA5) and retinoic acid-inducible gene 1 (RIG-1) as the pattern recognition receptors play important roles in viral mRNA recognition. Chronic HBV-infected (CHB) patients are unable to properly respond to hepatitis B virus (HBV). Therefore, the aim of the present study was to evaluate the mRNA levels of MDA5 and RIG-1 in the peripheral blood immune cells of CHB patients in comparison to healthy controls. In this cross-sectional study, the mRNA levels of MDA5 and RIG-1 were examined in 60 CHB patients and 60 healthy controls using the real-time polymerase chain reaction (PCR) technique. Our results showed that mRNA levels of MDA5 and RIG-1 were significantly decreased and increased, respectively, in CHB patients when compared to healthy controls. Our results also revealed that mRNA levels of MDA5 and RIG-1 were not altered among CHB patients with various states of e-antigen of hepatitis B and HBV-DNA viral loads. According to the results presented here, it may be concluded that downregulation of MDA5 may be a responsible mechanism from several reasons, which leads to HBV persistence in CHB patients.