Lipid peroxidation: Its effects on the formulation and use of pharmaceutical emulsions

Effect of galangin on oxidative stress, antioxidant defenses and mitochondrial dynamics in a rat model of focal cerebral ischemia

Focal ischemia occurs when a cerebral artery becomes obstructed by an embolus or thrombus, leading to a rapid reduction in cerebral blood flow and significantly increasing the risk of mortality and disability. This condition is of particular concern in developing countries, where its prevalence is on the rise. Galangin, a flavonoid found in Alpinia officinarum, shows strong antioxidant, anti-inflammatory and anti-apoptotic properties. Its wide-ranging bioactivity in both in vitro and animal studies points to promising therapeutic applications. Given the role of oxidative stress in the pathophysiology of focal ischemia, the present study explored the effects of galangin on oxidative stress markers and antioxidant defenses in an animal model of the disease. A total of 60 healthy male Wistar rats were randomly assigned to six groups: Control, right middle cerebral artery occlusion (Rt.MCAO) + vehicle, Rt.MCAO + piracetam, and Rt.MCAO + galangin at doses of 25, 50 and 100 mg/kg body weight. The results indicated that 7 days of galangin treatment reduces infarct volume, malondialdehyde levels, and the density ratio of mitogen-activated protein kinase, while enhancing catalase, glutathione peroxidase and superoxide dismutase activities, and improving the density ratio of mitofusin 2 protein in the cortex and hippocampus. In conclusion, galangin showed significant in vivo potential in mitigating the pathological changes caused by cerebral ischemia, likely due to its antioxidant properties and modulation of mitochondrial dynamics. Additional research is now needed to explore the biochemical and neurological impacts of galangin in focal cerebral ischemia and to fully elucidate its mechanism of action.

Analysis of the Efficiency of Antioxidants in Inhibiting Lipid Oxidation in Terms of Characteristic Kinetic Parameters

In this work, we aim to find physical evidence demonstrating the crucial role that the effective concentration of antioxidants (AOs) present at the interfacial region of emulsions has in controlling the inhibition of the lipid oxidation reaction. We prepared a series of antioxidants of different hydrophobicities derived from chlorogenic and protocatechuic acids. We first monitored, in intact emulsions, the (sigmoidal) production of conjugated dienes and determined the corresponding induction times, tind. Independently, we determined the effective concentrations of the antioxidants in the same intact emulsions. Results show that both the length of the induction periods and the antioxidant interfacial concentrations parallel each other, with a maximum at the octyl-dodecyl derivatives. The ratio between the interfacial antioxidant concentrations and the induction periods remains constant for all AOs in the same series, so that the rates of initiation of lipid oxidation are the same regardless of the hydrophobicity of the antioxidant employed. The constancy in the rate of initiation provides strong experimental evidence for a direct relationship between interfacial concentrations and antioxidant efficiencies. Results suggest new possibilities to investigate lipid peroxidation under non-forced conditions and are of interest to formulators interested in preparing emulsions with antimicrobial properties.

Arabic gum grafted with phenolic acid as a novel functional stabilizer for improving the oxidation stability of oil-in-water emulsion

Three kinds of phenolic acids: ferulic acid (FA), caffeic acid (CA), and gallic acid (GA) with different chemical structures were individually grafted onto Arabic gum (AG) via a laccase mediated method, and their roles in stabilizing o/w emulsions were evaluated. The total phenolic content in modified AG increased from 2.7 ± 0.2 to 18.7 ± 0.2, 19.8 ± 0.6, 22.4 ± 0.8 mg/g after 4 h of laccase catalysis, respectively. FTIR spectra of modified AGs exhibited additional phenolic characteristics, revealing the successful grafting of phenolic acids to AG structure. Compared with natural AG, modified AGs showed remarkably enhanced thermal stability, as well as antioxidant capacity in an order of gallic acid > caffeic acid > ferulic acid. The incorporation of phenolic acids into AG dramatically improved its emulsification performance. Herein, gallic acid-modified AG evinced up to 17.6 % and 12.6 % increments in emulsifying activity and emulsion stability relative to natural AG, respectively. Moreover, the oxidative stability of AG emulsions was pronouncedly meliorated by the introduced phenolic acids, especially gallic acid, as manifested by the suppressed production of primary and secondary oxidation products.

n-3 Polyunsaturated Fatty Acid Supplementation Affects Oxidative Stress Marker Levels in Patients with Type II Intestinal Failure: A Randomized Double Blind Trial

Type II intestinal failure (IF-II) is a condition in which the gastrointestinal tract is compromised. Liver complications may occur because of the pathology and/or prolonged use of parenteral nutrition (PN); oxidative stress has been implicated as one of the causes. Lipid emulsions containing n-3 polyunsaturated fatty acids (PUFAs) have been proposed for the treatment. We aimed to evaluate the effect of 7-day n-3 PUFA supplementation on oxidative stress in IF-II patients receiving PN. This was a randomized, controlled, double-blinded, pilot trial of adult patients with IF-II, receiving either conventional PN (control) or PN enriched with n-3 PUFAs (intervention). Twenty patients were included (14 men, 49 ± 16.9 years), with the ANCOVA analysis the glucose (p = 0.003), and direct bilirubin (p = 0.001) levels reduced; whereas the high-density lipoprotein cholesterol (HDL-C) increased (p = 0.017). In the random-effect linear regression analysis, a reduction (p < 0.0001) in the malondialdehyde (MDA) level was found in the intervention group when the covariables age, HDL-C level, and alanine aminotransferase activity were considered. After 1 week of PN supplementation with n-3 PUFAs, the marker levels of some oxidative stress, blood lipids, and hepatic biomarkers improved in patients with IF-II.

Honokiol-Loaded Nanoemulsion for Glioblastoma Treatment: Statistical Optimization, Physicochemical Characterization, and an In Vitro Toxicity Assay

BACKGROUND

Glioblastoma (GBM) is an extremely invasive and heterogenous malignant brain tumor. Despite advances in current anticancer therapy, treatment options for glioblastoma remain limited, and tumor recurrence is inevitable. Therefore, alternative therapies or new active compounds that can be used as adjuvant therapy are needed. This study aimed to develop, optimize, and characterize honokiol-loaded nanoemulsions intended for intravenous administration in glioblastoma therapy.

METHODS

Honokiol-loaded nanoemulsion was developed by incorporating honokiol into Lipofundin MCT/LCT 20% using a horizontal shaker. The Box-Behnken design, coupled with response surface methodology, was used to optimize the incorporation process. The effect of the developed formulation on glioblastoma cell viability was determined using the MTT test. Long-term and short-term stress tests were performed to evaluate the effect of honokiol on the stability of the oil-in-water system and the effect of different stress factors on the stability of honokiol, respectively. Its physicochemical properties, such as MDD, PDI, ZP, OSM, pH, and loading efficiency (LE%), were determined.

RESULTS

The optimized honokiol-loaded nanoemulsion was characterized by an MDD of 201.4 (0.7) nm with a PDI of 0.07 (0.02) and a ZP of -28.5 (0.9) mV. The LE% of honokiol was above 95%, and pH and OSM were sufficient for intravenous administration. The developed formulation was characterized by good stability and a satisfactory toxicity effect of the glioblastoma cell lines.

CONCLUSIONS

The honokiol-loaded nanoemulsion is a promising pharmaceutical formulation for further development in the adjuvant therapy of glioblastoma.

Physicochemical Evaluation of Personal Care Products Developed with Chondrus crispus Fractions Processed by Ecofriendly Methodologies

Novel personal care products are necessary to cope with the growing market demand for sustainable green products. In this context, this work deals with the formulation and fundamental physicochemical and rheological characterization of different natural personal care products using bioactive fractions from Chondrus crispus red macroalgae extracted under optimized green conditions. Body milks, body oils and shampoos were supplemented with soluble extracts with antioxidant features recovered after hydrothermal (200 °C) and microwave (170 °C)- and ultrasound (80 °C)-assisted extraction of the red macroalgae used as raw material. Formulated products were also compared with those prepared using (±)-α-tocopherol and butylhydroxytoluene standards. Body scrubs were formulated with the remaining solids (<2.25%) after microwave hydrodiffusion and gravidity treatment of the macroalgae. Results indicated that selected extracts provided personal care products with similar or even better physicochemical, color and viscous features than those supplemented with (±)-α-tocopherol or butylhydroxytoluene commercial antioxidants. Rheological profiles indicated that it is possible to develop personal care products with adequate viscous behavior (102−105 mPa s, at 1 s−1), comparable with their synthetic counterparts. To conclude, the addition of antioxidant extracts led to lower apparent viscosity values suggesting an advantage from the skin applicability point of view, jointly with the absence of both the hysteresis phenomenon and water syneresis of the proposed formulations.

Levofloxacin in nanostructured lipid carriers: Preformulation and critical process parameters for a highly incorporated formulation

The first step of a successful nanoformulation development is preformulation studies, in which the best excipients, drug-excipient compatibility and interactions can be identified. During the formulation, the critical process parameters and their impact must be studied to establish the stable system with a high drug entrapment efficiency (EE). This work followed these steps to develop nanostructured lipid carriers (NLCs) to deliver the antibiotic levofloxacin (LV). The preformulation studies covered drug solubility in excipients and thorough characterization using thermal analysis, X-ray diffraction and spectroscopy. A design of experiment based on the process parameters identified nanoparticles with < 200 nm in size, polydispersity <= 0.3, zeta potential -21 to -24 mV, high EE formulations (>71 %) and an acceptable level of LV degradation products (0.37-1.13 %). To the best of our knowledge, this is the first time that a drug degradation is reported and studied in work on nanostructured lipids. LV impurities following the NLC production were detected, mainly levofloxacin N-oxide, a degradation product that has no antimicrobial activity and could interfere with LV quantification in spectrophotometric experiments. Also, the achievement of the highest EE in lipid nanoparticles than those described in the literature to date and the apparent protective action of NLC of entrapped-LV against degradation are important findings.

Review of High-Frequency Ultrasounds Emulsification Methods and Oil/Water Interfacial Organization in Absence of any Kind of Stabilizer

Emulsions are multiphasic systems composed of at least two immiscible phases. Emulsion formulation can be made by numerous processes such as low-frequency ultrasounds, high-pressure homogenization, microfluidization, as well as membrane emulsification. These processes often need emulsifiers' presence to help formulate emulsions and to stabilize them over time. However, certain emulsifiers, especially chemical stabilizers, are less and less desired in products because of their negative environment and health impacts. Thus, to avoid them, promising processes using high-frequency ultrasounds were developed to formulate and stabilize emulsifier-free emulsions. High-frequency ultrasounds are ultrasounds having frequency greater than 100 kHz. Until now, emulsifier-free emulsions' stability is not fully understood. Some authors suppose that stability is obtained through hydroxide ions' organization at the hydrophobic/water interfaces, which have been mainly demonstrated by macroscopic studies. Whereas other authors, using microscopic studies, or simulation studies, suppose that the hydrophobic/water interfaces would be rather stabilized thanks to hydronium ions. These theories are discussed in this review.

Royal jelly plus coenzyme Q10 supplementation improves high-intensity interval exercise performance via changes in plasmatic and salivary biomarkers of oxidative stress and muscle damage in swimmers: a randomized, double-blind, placebo-controlled pilot trial

Background

Excessive production of free radicals caused by many types of exercise results in oxidative stress, which leads to muscle damage, fatigue, and impaired performance. Supplementation with royal jelly (RJ) or coenzyme Q10 (CoQ10) has been shown to attenuate exercise-induced oxidant stress in damaged muscle and improve various aspects of exercise performance in many but not all studies. Nevertheless, the effects of treatments based on RJ plus CoQ10 supplementation, which may be potentially beneficial for reducing oxidative stress and enhancing athletic performance, remain unexplored. This study aimed to examine whether oral RJ and CoQ10 co-supplementation could improve high-intensity interval exercise (HIIE) performance in swimmers, inhibiting exercise-induced oxidative stress and muscle damage.

Methods

Twenty high-level swimmers were randomly allocated to receive either 400 mg of RJ and 60 mg of CoQ10 (RJQ) or matching placebo (PLA) once daily for 10 days. Exercise performance was evaluated at baseline, and then reassessed at day 10 of intervention, using a HIIE protocol. Diene conjugates (DC), Schiff bases (SB), and creatine kinase (CK) were also measured in blood plasma and saliva before and immediately after HIIE in both groups.

Results

HIIE performance expressed as number of points according to a single assessment system developed and approved by the International Swimming Federation (FINA points) significantly improved in RJQ group (p = 0.013) compared to PLA group. Exercise-induced increase in DC, SB, and CK levels in plasma and saliva significantly diminished only in RJQ group (p < 0.05). Regression analysis showed that oral RJQ administration for 10 days was significantly associated with reductions in HIIE-induced increases in plasmatic and salivary DC, SB, and CK levels compared to PLA. Principal component analysis revealed that swimmers treated with RJQ are grouped by both plasmatic and salivary principal components (PC) into a separate cluster compared to PLA. Strong negative correlation between the number of FINA points and plasmatic and salivary PC1 values was observed in both intervention groups.

Conclusion

The improvements in swimmers’ HIIE performance were due in significant part to RJQ-induced reducing in lipid peroxidation and muscle damage in response to exercise. These findings suggest that RJQ supplementation for 10 days is potentially effective for enhancing HIIE performance and alleviating oxidant stress.

Abbreviations

RJ, royal jelly; CoQ10, coenzyme Q10; HIIE, high-intensity interval exercise; DC, diene conjugates; SB, Schiff bases; CK, creatine kinase; RJQ, royal jelly plus coenzyme Q10; PLA, placebo; FINA points, points according to a single assessment system developed and approved by the International Swimming Federation; ROS, reactive oxygen species; 10H2DA, 10-hydroxy-2-decenoic acid; AMPK, 5′-AMP-activated protein kinase; FoxO3, forkhead box O3; MnSOD, manganese-superoxide dismutase; CAT, catalase; E, optical densities; PCA, principal component analysis; PC, principal component; MCFAs, medium-chain fatty acids; CaMKKβ, Ca²⁺/calmodulin-dependent protein kinase β; TBARS, thiobarbituric acid reactive substances; MDA, malondialdehyde.

Measurement of Lipid Peroxidation Products and Creatine Kinase in Blood Plasma and Saliva of Athletes at Rest and following Exercise

This study aimed to assess the agreement between quantitative measurements of plasmatic and salivary biomarkers capable of identifying oxidative stress and muscle damage in athletes at rest and following exercise. Thirty-nine high-level athletes participating in track and field (running), swimming or rowing were recruited and assigned to one of three groups depending on the sport. Each athlete group underwent its specific exercise. Blood and saliva samples were collected before and immediately after the exercise. Diene conjugates (DC), triene conjugates (TC), Schiff bases (SB), and creatine kinase (CK) were measured. Comparisons were made using Wilcoxon signed-rank test. Correlation analysis and Bland−Altman method were applied. DC levels were elevated in plasma (p < 0.01) and saliva (p < 0.01) in response to exercise in all three groups, as were the plasmatic (p < 0.01) and salivary (p < 0.01) TC and SB concentrations. CK activity was also significantly higher at postexercise compared to pre-exercise in both plasma (p < 0.01) and saliva (p < 0.01) in all groups. Strong positive correlation between salivary and plasmatic DC (p < 0.001), TC (p < 0.001), SB (p < 0.01), and CK (p < 0.001) was observed at rest and following exercise in each athlete group. The bias calculated for DC, TC, SB, and CK using the Bland−Altman statistics was not significant at both pre-exercise and postexercise in all three groups. The line of equality was within the confidence interval of the mean difference. All of the data points lay within the respective agreement limits. Salivary concentrations of DC, TC, SB, and CK are able to reliably reflect their plasma levels.

Oxidative Stability in Lipid Formulations: a Review of the Mechanisms, Drivers, and Inhibitors of Oxidation

The importance of lipid-based formulations in addressing solubility and ultimately the bioavailability issues of the emerging drug entities is undeniable. Yet, there is scarcity of literature on lipid excipient chemistry and performance, notably in relation to oxidative stability. While not all lipid excipients are prone to oxidation, those with sensitive moieties offer drug delivery solutions that outweigh the manageable oxidative challenges they may present. For example, caprylocaproyl polyoxylglycerides help solubilize and deliver cancer drug to patients, lauroyl polyoxylglycerides enhance the delivery of cholesterol lowering drug, and sesame/soybean oils are critical part of parenteral nutrition. Ironically, excipients with far greater oxidative propensity are omnipresent in pharmaceutical products, a testament to the manageability of oxidative challenges in drug development. Successful formulation development requires awareness of what, where, and how formulation stability may be impacted, and accordingly taking appropriate steps to circumvent or meet the challenges ahead. Aiming to fill the information gap from a drug delivery scientist perspective, this review discusses oxidation pathways, prooxidants, antioxidants, and their complex interplay, which can paradoxically take opposite directions depending on the drug delivery system.

Evaluation of the biological activities of β-glucan isolated from Lentinula edodes

Lentinula edodes (shiitake) is an edible mushroom that contains many constituents and β-glucan is considered a major polysaccharide. This study, therefore, aimed to characterize β-glucan and evaluate its activities. Fresh fruit bodies of L. edodes were used for β-glucan extraction and followed by analyses via Fourier transform infrared, Nuclear magnetic resonance, and High Performance Liquid Chromatography confirming its characteristic structure. For evaluating biological activities of β-glucan, different concentrations (0.1-3.5 mg ml^-1 ) were assessed. The optimal dose was 3.5 mg ml^-1 that showed the highest scavenging radical ability (75.3%) confirms antioxidant activity, strong inhibition of the peroxyl radical (80.9%) to inhibit lipid peroxidation, elevation the inhibition percentage of both α-amylase (73.4%) and α-glucosidase (70.3%) indicates the antidiabetic properties, and highest AFB1 reduction (88%) which ensured the aflatoxin-detoxifying ability. In addition, antifungal activity of β-glucan was evaluated to inhibit sporulation process in Aspergillus niger and recorded with minimum inhibitory concentration of 2.5 mg ml^-1 and minimum fungicidal concentration of 3 mg ml^-1 . In a dose-dependent manner, higher concentration of β-glucan affects viability of tumor cells concomitant induces potent anti-cancer immune responses and inhibited the activity of topoisomerase I which are considered an important target for cancer chemotherapy. Therefore, L. edodes-β-glucan has the potential to act as a suggestive agent for antioxidant, antidiabetic, antifungal activity, and aflatoxin detoxification.

Impact of Fixed Oil on Ostwald Ripening of Anti-Oral Cancer Nanoemulsions Loaded with Amomum kravanh Essential Oil

Recently, essential oil from Amomum kravanh (AMO) was reported to exert anti-oral cancer effects. Although it was more effective after being loaded into nanoemulsions, AMO without an Ostwald ripening inhibitor was unable to form stable nanoemulsions because of the Ostwald ripening phenomenon. In this study, we examined the influence of Ostwald ripening inhibitors, such as fixed oils and polyethylene glycol 4000 (PEG 4000), on nanoemulsion properties prepared by a phase inversion temperature method. Several fixed oils, including virgin coconut oil (VCO), palm oil (PMO), olive oil (OLO), and PEG 4000, were evaluated, and their Ostwald ripening inhibitory effects were compared. The results suggest that the type and ratio of AMO:fixed oils influence the formation and characteristics of nanoemulsions. PEG 4000 was unable to produce nanoemulsions; however, stable nanoemulsions with small droplet sizes were observed in preparations containing OLO and VCO at an AMO:fixed oil ratio of 80:20, which may be the result of specific molecular interactions among the components. Using an MTT assay, we demonstrated that the AMO:OLO (80:20) nanoemulsion produced the most significant cytotoxic effect on oral cancer cells with a percentage of 99.68 ± 0.56%. Furthermore, the AMO:OLO 80:20 nanoemulsion inhibits metastasis and induces oral cancer cell death through the intrinsic apoptosis pathway. In conclusion, AMO nanoemulsion with anti-oral cancer activity was successfully produced by varying the amount and type of fixed oils. In the future, this discovery may lead to the development of stable nanoemulsions employing additional volatile oils.

An updated review on efficacy and benefits of sweet almond, evening primrose and jojoba oils in skin care applications

Renewed consumer and industry interest in natural ingredients has led to a large growth of natural cosmetics. This has put pressure on formulation skills and product claims when it comes to using natural compounds. Taking a strategic and comprehensive approach in viewing natural ingredients, including natural oils, as 'active' ingredients rather than just providing for so-called 'natural' claims, aids both innovation and development. Given the ever-increasing consumer demand for natural ingredients, and more importantly the demand for effective natural ingredients including plant oils, it is important for the cosmetic industry to re-evaluate them in this context. The objectives of this review are to provide an update of three popular cosmetic plant oils - Sweet Almond, Evening Primrose, and Jojoba - in terms of their cosmetic applications as 'active' ingredients. This review highlights the activity of these oils, in the management of dry skin, ageing skin, juvenile skin, atopic dermatitis, scalp conditions, and their wider potential. Attention is given to formulation considerations where the content of these oils impacts product oxidation, skin penetration and stratum corneum homeostasis. Benefits of these oils have been well documented both pre-clinically and clinically. Historically, they have been used for hundreds if not thousands of years for their management and treatment of various skin and other ailments. Given the discrepancies in some clinical data presented for a variety of dermatoses, the importance of the choice of oil and how to formulate with them within the context of the epidermal barrier function, skin penetration, and toxicity, cannot be underestimated. Care should be taken in terms of the quality and stability of theses oils, as well as ensuring best formulation type, if the reported activities of these oils are to be achieved with consistency. Despite discrepancies in the literature and questionable study designs, it is clear, that Sweet Almond, Evening Primrose and Jojoba oils, do have skin care benefits for both adult and juvenile applications. They are effective ingredients for skin care preparations to strengthen stratum corneum integrity, recovery, and lipid ratio. Nevertheless, further experimental data are required concerning the impact on stratum corneum physiology and structure.

Bioactive Lipids and Their Derivatives in Biomedical Applications

Lipids, which along with carbohydrates and proteins are among the most important nutrients for the living organism, have a variety of biological functions that can be applied widely in biomedicine. A fatty acid, the most fundamental biological lipid, may be classified by length of its aliphatic chain, and the short-, medium-, and long-chain fatty acids and each have distinct biological activities with therapeutic relevance. For example, short-chain fatty acids have immune regulatory activities and could be useful against autoimmune disease; medium-chain fatty acids generate ketogenic metabolites and may be used to control seizure; and some metabolites oxidized from long-chain fatty acids could be used to treat metabolic disorders. Glycerolipids play important roles in pathological environments, such as those of cancers or metabolic disorders, and thus are regarded as a potential therapeutic target. Phospholipids represent the main building unit of the plasma membrane of cells, and play key roles in cellular signaling. Due to their physical properties, glycerophospholipids are frequently used as pharmaceutical ingredients, in addition to being potential novel drug targets for treating disease. Sphingolipids, which comprise another component of the plasma membrane, have their own distinct biological functions and have been investigated in nanotechnological applications such as drug delivery systems. Saccharolipids, which are derived from bacteria, have endotoxin effects that stimulate the immune system. Chemically modified saccharolipids might be useful for cancer immunotherapy or as vaccine adjuvants. This review will address the important biological function of several key lipids and offer critical insights into their potential therapeutic applications.

Enhancement of Chemical Stability and Dermal Delivery of Cordyceps militaris Extracts by Nanoemulsion

This study aimed to develop nanoemulsions for enhancing chemical stability and dermal delivery of Cordyceps militaris extracts. C. militaris was extracted by maceration and infusion. The extracts were investigated for cordycepin, phenolic, and flavonoid content. The antioxidant activity was investigated by in vitro spectrophotometric methods. The irritation profile was investigated by hen's egg-chorioallantoic membrane test. Nanoemulsions were developed using high-pressure homogenizer. C. militaris extract was incorporated into the nanoemulsion and investigated for safety, release profile, permeation, and skin retention. The results demonstrated that water extract (CW) contained the significantly highest content of cordycepin, phenolics, and flavonoids, which were responsible for antioxidant activity. CW was the most potent antioxidant. CW possessed comparable 2,2'-diphenyl-1-picrylhydrazyl radical scavenging activity and lipid peroxidation inhibition to l-ascorbic acid (96.9 ± 3.1%) and alpha-tocopherol (87.2 ± 1.0%). Consequently, ten mg/mL of CW was incorporated into nanoemulsions composing of sugar squalene, Tween® 85, and deionized water. Nanoemulsion, which had the smallest internal droplet size (157.1 ± 2.6 nm), enhanced the stability of CW, had no cytotoxicity effect and no skin irritation, released the most CW (0.9 ± 0.0% w/w after 24 h), and delivered the highest CW into the skin layer (33.5 ± 0.7% w/w). Therefore, nanoemulsion was suggested for enhancing the stability and dermal delivery of CW.

Characterization of Retinol Stabilized in Phosphatidylcholine Vesicles with and without Antioxidants

Retinol stability has been reported to be improved by encapsulation in liposomes, both with and without cholesterol. However, this improvement is limited because of lipid peroxidation. In this study, we compare the stability of retinol in phosphatidylcholine liposomes under ultraviolet (UV) light or standard room air, with and without the addition of antioxidants. Both butylated hydroxytoluene (BHT) and a proprietary mix (StoppOx) improved the shelf stability from <10 to over 30 d. The addition of cholesterol had no effect. Fluorescence imaging showed a heterogeneous distribution of retinol within the vesicles, including within the aqueous layer. Fluorescence lifetimes were equally heterogeneous. Under UV irradiation, StoppOx protected retinol for significantly longer than BHT and via different mechanisms. This suggests that natural antioxidants work well to improve the retinol stability, but that further work to determine the optimal vesicle structure remains to be performed.

Fast, direct and in situ monitoring of lipid oxidation in an oil-in-water emulsion by near infrared spectroscopy

Lipid oxidation has implications on food, cosmetics and other fat containing products. Fatty acid autoxidation alters both the quality and safety of these products. Efficient and fast methods are needed to track lipid oxidation in complex systems. In this study, an oil-in-water emulsion (20% v/v of fish oil stabilized with high oleic sunflower lecithin) was subjected to iron-initiated oxidation. Conjugated dienes (CDs) were measured after fat extraction using a standardized method. Near infrared spectroscopy (NIRS) has been used to record chemical changes occurring during oxidation directly in the emulsion. Variations were noticed in different spectral regions. Partial least squares regression (PLSR) revealed correlations between conjugated diene values and NIRS spectra. High coefficients of determination (R2 = 0.967 and 0.996) were found for calibration and prediction respectively. The CD value was predicted from NIRS spectra with an error of 7.26 mmol eq. LH kg-1 oil (7.8% error). Limits of detection (LOD) and quantification (LOQ) of 4.65 and 15.5 mmol eq. LH kg-1 oil were estimated. NIRS is a rapid and simple method for measuring lipid oxidation (CD value) in an emulsion without prior fat extraction. NIRS can replace the reference methods that use hazardous solvents and consume time. Therefore, NIRS enables in-line monitoring for process and quality control.

Carminic Acid Linked to Silica Nanoparticles as Pigment/Antioxidant Bifunctional Excipient for Pharmaceutical Emulsions

The incorporation of pigments and natural polyphenols into inorganic matrices, resulting in a hybrid material that improves the resistance and chemical stability of the pigments and the antioxidant capacity of the materials, has been of great interest to the pharmaceutical, chemical and food industries. The aim of this work was to prepare and characterize a bifunctional pigment-antioxidant nanomaterial-based carminic acid-decorated solid core-mesoporous shell silica nanoparticles, evaluating its properties as a pigment, its antioxidant capacity and its properties as a chemical stabilizer of emulsions. The chemical stability of oil-in-water (O/W) Pickering emulsions was evaluated determining the stability of vitamin E solubilized in the oil phase. Carminic acid was attached through the action of coupling ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) agents, and the resulting spherical and homogeneous nanoparticles showed a diameter close to 175 nm. A notorious change of emulsion color was observed by the addition of the nanomaterial. Emulsions showed an attractive pink color, and when the pH was adjusted to pH 3 and pH 9, a change in color was observed, analogous to carminic acid in solution. The nanomaterial incorporation also improved chemical stability, decreasing vitamin E consumption to 9.26% of the initial value, demonstrating an important antioxidant effect of the developed nanomaterial.

Techno-biofunctionality of mangostin extract-loaded virgin coconut oil nanoemulsion and nanoemulgel

Techno-biofunctional characteristics of nanoemulsion and (nano)emulgel loaded with mangostin extracts were elucidated. Crude mangostins from mangosteen peels recovered by virgin coconut oil (VCO), mixed VCO and propylene glycol (PG), and pure PG were used. The extracts were loaded in the dispersed phase in the presence of mixed surfactants (Tween20/Span20) with a varying hydrophilic-lipophilic balance (HLB) from 10.2 to 15.1. Results showed that globular and uniformly distributed droplets of the nanoemulsion were observed. The small particle sizes (typically 18-62 nm) with the zeta potential of -39 to -54.5 mV were obtained when mixed emulsifiers with HLB values of 12.6 and 15.1 were employed. With HLB values of 12.6 and 15.1, nanoemulsions loaded with mangostin extracts prepared with mixed VCO-PG and pure PG-based extracts showed approximately a 2 to 3-fold lower droplet size diameter when compared with the VCO-based extract. For the stability test, all nanoemulsions were stable over three freeze-thaw cycles with some changes in pH, zeta potential, and droplet size. The DPPH● scavenging activity, H2O2 scavenging activity, reducing power and antibacterial activities (E. coli and S. aureus) of the nanoemulsions were greater than their corresponding bulk extracts. Nanoemulgels produced by embedding the nanoemulsions in a hydrogel matrix was homogeneous and creamy yellow-white in appearance. The nanoemulgels had a higher mangostin release (87-92%) than their normal emulgels (74-78%). Therefore, this study presented the feasibility of nanoemulsions and nanoemulgels loaded with mangostin extracts as a promising delivery system for bioactive polyphenol in food supplements, pharmaceuticals and cosmetics.

Influence of Ternary Emulsifier Mixtures on Oxidative Stability of Nanoemulsions Based on Avocado Oil

The aim of this work was to study the effect of two emulsifiers (M1: SL-soy lecithin, Tw80-Tween 80 and CasCa-calcium caseinate and M2: SL-soy lecithin, Tw80-Tween 80 and SE-sucrose esters) on the oxidative stability of avocado oil-based nanoemulsions. Oil-in-water nanoemulsions were prepared using 3.6% w/w of two emulsifier mixtures, which were optimized by mixture experimental design in order to minimize particle size (PS) and polydispersity index (PdI). Then, the oxidative stability of nanoemulsions was evaluated through both an induction period and a quantification of hydroperoxides and thiobarbituric acid reactive species (TBARs) under accelerated storage conditions. The simplex-centroid mixture design showed that PS and PdI varied when proportions of different emulsifiers were modified, obtaining an optimized concentration for each mixture of: 85% SL, 10% Tw80 and 5%CasCa (M1) and 85% SL, 7.4% Tw80 and 7.6% SE (M2) that produced nanoemulsions with PS ~116 nm and PdI < 0.2. Nanoemulsions elaborated with M1 and M2 presented similar particle characteristics and physical stability to the control sample with Tw80. However, M1 nanoemulsions were more stable against lipid oxidation, since they showed the highest induction period and lower formation of hydroperoxides and TBARs during storage.

Preparation, characteristics, and antioxidant activities of carboxymethylated polysaccharides from blackcurrant fruits

In the present study, the native polysaccharide (RNP) extracted from blackcurrant fruits was carboxymethylated. Physicochemical characteristics and antioxidant activities in vitro of RNP and three carboxymethylated polysaccharides (CRNPs) were determined. GC analysis proved that RNP and CRNPs were composed of the same six monosaccharides (galacturonic acid, rhamnose, arabinose, mannose, glucose and galactose), but the molar ratios of monosaccharides were different. HPLC demonstrated that the molecular weights of CRNPs were improved. The assays of the antioxidant properties indicated that CRNPs possessed stronger scavenging activities on radicals (hydroxyl and superoxide radicals) and better anti-lipid peroxidation activities, as well as better protection effects on erythrocyte hemolyses in vitro compared with RNP. The activities of CRNPs were significantly enhanced with the increase of the degree of substitution (DS). These results proved that the carboxymethylation could effectively increase the antioxidant activities of the polysaccharide.

Nitrone-Trolox conjugate as an inhibitor of lipid oxidation: Towards synergistic antioxidant effects

Free radical scavengers like α-phenyl-N-tert-butylnitrone (PBN) and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) have been widely used as protective agents in various biomimetic and biological models. A series of three amphiphilic Trolox and PBN derivatives have been designed by adding to those molecules a perfluorinated chain as well as a sugar group in order to render them amphiphilic. In this work, we have studied the interactions between these derivatives and lipid membranes to understand how they influence their ability to prevent membrane lipid oxidation. We showed the derivatives better inhibited the AAPH-induced oxidation of 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLiPC) small unilamellar vesicles (SUVs) than the parent compounds. One of the derivatives, bearing both PBN and Trolox moieties on the same fluorinated carrier, exhibited a synergistic antioxidant effect by delaying the oxidation process. We next investigated the ability of the derivatives to interact with DLiPC membranes in order to better understand the differences observed regarding the antioxidant properties. Surface tension and fluorescence spectroscopy experiments revealed the derivatives exhibited the ability to form monolayers at the air/water interface and spontaneously penetrated lipid membranes, underlying pronounced hydrophobic properties in comparison to the parent compounds. We observed a correlation between the hydrophobic properties, the depth of penetration and the antioxidant properties and showed that the location of these derivatives in the membrane is a key parameter to rationalize their antioxidant efficiency. Molecular dynamics (MD) simulations supported the understanding of the mechanism of action, highlighting various key physical-chemical descriptors.

Targeting Antioxidants to Interfaces: Control of the Oxidative Stability of Lipid-Based Emulsions

The oxidation of lipid-based emulsions and nanoemulsions strongly affects their overall quality and safety. Moreover, introduction of oxidatively unstable emulsions into biological systems either as an energy source in parenteral nutrition or as delivery systems of bioactives may promote oxidation "in situ" leading to the overproduction of reactive oxygen species, initiating new harmful oxidative reactions and increasing the oxidative damage. Addition of antioxidants, AOs, may help to prevent the oxidative degradation of unsaturated lipids. Nevertheless, prediction of the optimal antioxidant or set of antioxidants and their efficiency is still far from being completely understood because the site of reaction is often uncertain and because the effective concentrations of reactants in the different regions of the emulsion have been frequently overlooked. Furthermore, the absence of quantitative relationships between the hydrophobicity of the antioxidants and their partitioning among the oil, water, and interfacial regions hampers their optimal use. Here we investigated the effects of gallic acid and some of its alkyl derivatives on the oxidative stability of soybean oil-in-water emulsions and determined their effective concentrations in the different regions of the emulsion (aqueous, oil, and interface). The results provide physical evidence for the crucial role played by the interfacial region in the reaction between antioxidants and lipid radicals: a direct relationship between interfacial concentrations and the oxidative stability could be established. The results indicate that AOs accumulate in the interfacial region, where the effective concentration is 20-180 times higher than the stoichiometric concentrations. Control of the hydrophobicity of the AOs and of the surfactant concentration allows control of interfacial concentrations: the lower the concentration of surfactant employed, the higher the effective interfacial concentration.

Solidification to improve the biopharmaceutical performance of SEDDS: Opportunities and challenges

Self-emulsifying drug delivery systems (SEDDS) offer potential for overcoming the inherent slow dissolution and poor oral absorption of hydrophobic drugs by retaining them in a solubilised state during gastrointestinal transit. However, the promising biopharmaceutical benefits of liquid lipid formulations has not translated into widespread commercial success, due to their susceptibility to long term storage and in vivo precipitation issues. One strategy that has emerged to overcome such limitations, is to combine the solubilisation and dissolution enhancing properties of lipids with the stabilising effects of solid carrier materials. The development of intelligent hybrid drug formulations has presented new opportunities to harness the potential of emulsified lipids in optimising oral bioavailability for lipophilic therapeutics. Specific emphasis of this review is placed on the impact of solidification approaches and excipients on the biopharmaceutical performance of self-emulsifying lipids, with findings highlighting the key design considerations that should be implemented when developing hybrid lipid-based formulations.

Design, Fabrication, and In Vitro Evaluation of Nanoceria-Loaded Nanostructured Lipid Carriers for the Treatment of Neurological Diseases

Neurodegenerative diseases comprise a large group of disorders characterized by a dramatic synaptic connections loss, occurring as a result of neurodegeneration, which is closely related to the overproduction of reactive oxygen and nitrogen species. Currently, the treatment of neurodegenerative diseases has been limited mainly because of the inability of the synthesized delivery systems to cross the blood-brain barrier and to successfully deliver their therapeutic cargo to the diseased tissue. Taking into consideration the aforementioned limitations, we designed a lipid-based nanotherapeutic vector composed of biomimetic lipids and CeO₂ nanoparticles (nanoceria, NC). NC have shown to be a promising tool for the treatment of several pathological conditions ranging from cancer to neurological diseases, mainly because of their antioxidant properties, while lipid-based structures have been shown to have an inherent ability to cross the blood-brain barrier. The lipid-based nanotherapeutics were successfully fabricated using a combination of ultrasonication and high-pressure homogenization techniques, and they were fully characterized morphologically and physicochemically. Their antioxidant ability was demonstrated using electron paramagnetic resonance spectroscopy and antioxidant assays. These innovative nanotherapeutics demonstrated a higher colloidal stability with respect to free NC, preserving at the same time their antioxidant properties. Finally, the ability of the lipid carriers to cross a model of the blood-brain barrier and to be internalized by neurons, acting both as neuroprotective and pro-neurogenic agents, was demonstrated using single- and triple-culture systems.

Improvement of antihyperglycemic activity of nano-thymoquinone in rat model of type-2 diabetes

Thymoquinone is a bioactive constituent of Nigella sativa seeds. It has been reported to possess antihyperglycemic effect in rats. However, the effect of nanoformulation (NF) of thymoquinone has not been reported in literature. So, the present study was designed with the aim to investigate the effect of nanoformulation of thymoquinone in streptozotocin-nicotinamide induced type-2 diabetic rats and compare its effect with pure bioactive compound as well as metformin, a standard antidiabetic drug. It is the first study reporting the use of thymoquinone NF against diabetes. Polymeric nanocapsules (NCs) of thymoquinone and metformin were prepared by nanoprecipitation method using gum rosin, a biocompatible polymer. Box-Behnken statistical analysis tool was used for the optimization of polymer and other excipients. The NCs were then characterized with respect to particle size, stability, morphology, and in vitro drug dissolution profiles. Furthermore, thymoquinone (20, 40 & 80 mg/kg), metformin (150 mg/kg) and their nanoformulations (20, 40 & 80 mg/kg for thymoquinone and 80 mg/kg for metformin) per se were administered for 21 successive days to type-2 diabetic rats. Body weight and blood glucose levels were measured every week for 3 weeks. Serum lipid profile and glycosylated hemoglobin were estimated on 22^nd day. The nanocapsules were stable, spherical in shape and size was less than 100 nm. Thymoquinone-and metformin-loaded NCs showed sustained release profile as compared to their pure forms. Oral administration of thymoquinone, metformin and their nanoformulations significantly decreased blood glucose level and glycated haemoglobin; and improved the lipid profile of diabetic rats as compared to diabetic control rats. Thymoquinone-loaded NCs (containing 10, 20 and 40 mg of thymoquinone) produced dose-dependent antihyperglycemic effect and this effect was comparable to thymoquinone and metformin. In conclusion, thymoquinone nanocapsules (actually containing half of the doses of thymoquinone) produced better antihyperglycemic effect in type-2 diabetic rats as compared to thymoquinone alone.