Resveratrol self-emulsifying system increases the uptake by endothelial cells and improves protection against oxidative stress-mediated death

Self-Emulsifying Systems for Delivery of Bioactive Compounds from Natural Origin

Nature has been used as therapeutic resources in the treatment of diseases for many years. However, some natural compounds have poor water solubility. Therefore, physicochemical strategies and technologies are necessary for development of systems for carrying these substances. The self-emulsifying drug delivery systems (SEDDS) have been used as carriers of hydrophobic compounds in order to increase the solubility and absorption, improving their bioavailability. SEDDS are constituted with a mixture of oils and surfactants which, when come into contact with an aqueous medium under mild agitation, can form emulsions. In the last years, a wide variety of self-emulsifying formulations containing bioactive compounds from natural origin has been developed. This review provides a comprehensive overview of the main excipients and natural bioactive compounds composing SEDDS. In addition, applications, new technologies and innovation are reviewed as well. Examples of self-emulsifying formulations administered in different sites are also considered for a better understanding of the use of this strategy to modify the delivery of compounds from natural origin.

Cytotoxicity of iodine-131 radiopharmaceutical in tumor and non-tumor human cells and radioprotection by integral juices of Vitis labrusca L

Abstract Iodine-131 (I-131) radioisotope it causes the formation of free radicals, which lead to the formation of cell lesions and the reduction of cell viability. Thus, the use of radioprotectors, especially those from natural sources, which reduce the effects of radiation to healthy tissues, while maintaining the sensitivity of tumor cells, stands out. The objective of the present study was to evaluate the cytoprotective/radioprotective effects of whole grape juices manufactured from the conventional or organic production systems, whether or not exposed to ultraviolet (UV-C) light irradiation. The results showed that I-131 presented a cytotoxic effect on human hepatocellular cells (HepG2/C3A) at concentrations above 1.85 MBq/mL, after 24 and 48 hours of treatment, though all concentrations (0.0037 to 7.40 MBq/mL) were cytotoxic to non-tumor human lung fibroblast (MCR-5) cells, after 48 hours. However, grape juices (10 and 20 µL/mL) did not interfere with the cytotoxic effect of the therapeutic dose of I-131 on tumor cells within 48 hours of treatment, while protecting the non-tumor cells, probably due to its high antioxidant activity. In accordance with their nutraceutical potential, antioxidant and radioprotective activity, these data stimulate in vivo studies on the use of natural products as radioprotectants, such as grape juice, in order to confirm the positive beneficial potential in living organisms.

Resveratrol: nanocarrier-based delivery systems to enhance its therapeutic potential

Resveratrol (3,5,4'-trihydroxystilbene) is a polyphenolic compound existing in trees, peanuts and grapes and exhibits a broad spectrum of promising therapeutic activities, but it is unclear whether this entity targets the sites of action after oral administration. In vivo applicability of resveratrol has limited success so far, mainly due to its incompetent systemic delivery resulting from its low water solubility, poor bioavailability and short biological half-life. First-pass metabolism and presence of enterohepatic recirculation create doubt on the biological application of high doses typically used for in vitro trials. To augment bioavailability, absorption and uptake of resveratrol by cellular internalization, countless approaches have been implemented which involve the use of nanocarriers. Nanocarriers are a well-known delivery system used to reduce first-pass hepatic metabolism, overcome enterohepatic recirculation and accelerate the absorption of drugs via lymphatic pathways.

Characterizations and Bioavailability of Dendrimer-like Glucan Nanoparticulate System Containing Resveratrol

In this study, sugary maize dendrimer-like glucan (SMDG) was used as a delivery carrier for improving the bioavailability of resveratrol (RES). After optimization, the solubility of RES in RES-SMDG markedly increased to approximately 9.1 times that of the raw RES solution. The structural characterizations of the RES-SMDG formulation showed crystal RES was entrapped in the SMDG matrix for the amorphous state due to the strong intermolecular hydrogen bonds between the -OH of RES and glucan chains. In this case, antioxidant activity of RES-SMDG was markedly higher than that of the raw RES solution. In the Caco-2 cell model, the P_app value of RES in the RES-SMDG group was slightly higher than those of common permeable compounds, while the cellular uptake was significantly improved. RES-SMDG also exhibited protective effects against cellular damage under oxidative stress. The results indicated that SMDG is an attractive carrier to encapsulate and protect hydrophilic bioactive ingredients.

Natural products and phytochemical nanoformulations targeting mitochondria in oncotherapy: an updated review on resveratrol

Mitochondria are intracellular organelles with two distinct membranes, known as an outer mitochondrial membrane and inner cell membrane. Originally, mitochondria have been derived from bacteria. The main function of mitochondria is the production of ATP. However, this important organelle indirectly protects cells by consuming oxygen in the route of energy generation. It has been found that mitochondria are actively involved in the induction of the intrinsic pathways of apoptosis. So, there have been efforts to sustain mitochondrial homeostasis and inhibit its dysfunction. Notably, due to the potential role of mitochondria in the stimulation of apoptosis, this organelle is a promising target in cancer therapy. Resveratrol is a non-flavonoid polyphenol that exhibits significant pharmacological effects such as antioxidant, anti-diabetic, anti-inflammatory and anti-tumor. The anti-tumor activity of resveratrol may be a consequence of its effect on mitochondria. Multiple studies have investigated the relationship between resveratrol and mitochondria, and it has been demonstrated that resveratrol is able to significantly enhance the concentration of reactive oxygen species, leading to the mitochondrial dysfunction and consequently, apoptosis induction. A number of signaling pathways such as sirtuin and NF-κB may contribute to the mitochondrial-mediated apoptosis by resveratrol. Besides, resveratrol shifts cellular metabolism from glycolysis into mitochondrial respiration to induce cellular death in cancer cells. In the present review, we discuss the possible interactions between resveratrol and mitochondria, and its potential application in cancer therapy.

Development of a Resveratrol Nanosuspension Using the Antisolvent Precipitation Method without Solvent Removal, Based on a Quality by Design (QbD) Approach

The purpose of this study was to develop a resveratrol nanosuspension with enhanced oral bioavailability, based on an understanding of the formulation and process parameters of nanosuspensions and using a quality by design (QbD) approach. Particularly, the antisolvent method, which requires no solvent removal and no heating, is newly applied to prepare resveratrol nanosuspension. To ensure the quality of the resveratrol nanosuspensions, a quality target product profile (QTPP) was defined. The particle size (z-average, d90), zeta potential, and drug content parameters affecting the QTPP were selected as critical quality attributes (CQAs). The optimum composition obtained using a 3-factor, 3-level Box-Behnken design was as follows: polyvinylpyrrolidone vinyl acetate (10 mg/mL), polyvinylpyrrolidone K12 (5 mg/mL), sodium lauryl sulfate (1 mg/mL), and diethylene glycol monoethyl ether (DEGEE, 5% v/v) at a resveratrol concentration of 5 mg/mL. The initial particle size (z-average) was 46.3 nm and the zeta potential was -38.02 mV. The robustness of the antisolvent process using the optimized composition conditions was ensured by a full factorial design. The dissolution rate of the optimized resveratrol nanosuspension was significantly greater than that of the resveratrol raw material. An in vivo pharmacokinetic study in rats showed that the area under the plasma concentration versus time curve (AUC0-12h) and the maximum plasma concentration (Cmax) respectively, than those of the resveratrol raw material. Therefore, the prepara values of the resveratrol nanosuspension were approximately 1.6- and 5.7-fold higher,tion of a resveratrol nanosuspension using the QbD approach may be an effective strategy for the development of a new dosage form of resveratrol, with enhanced oral bioavailability.

Preparation and evaluation of self-microemulsions for improved bioavailability of ginsenoside-Rh1 and Rh2

Due to intestinal cytochrome P450 (CYP450)-mediated metabolism and P-glycoprotein (P-gp) efflux, poor oral bioavailability hinders ginsenoside-Rh1 (Rh1) and ginsenoside-Rh2 (Rh2) from clinical application. In this study, Rh1 and Rh2 were incorporated into two self-microemulsions (SME-1 and SME-2) to improve oral bioavailability. SME-1 contained both CYP450 and P-gp inhibitory excipients while SME-2 only consisted of P-gp inhibitory excipients. Results for release, cellular uptake, transport, and lymph node distribution demonstrated no significant difference between either self-microemulsions in vivo, but were elevated significantly in comparison to the free drug. The pharmaceutical profiles in vivo showed that the bioavailability of Rh1 in SME-1 (33.25%) was significantly higher than that in either SME-2 (21.28%) or free drug (12.92%). There was no significant difference in bioavailability for Rh2 between SME-1 (48.69%) or SME-2 (41.73%), although they both had remarkable increase in comparison to free drug (15.02%). We confirmed that SME containing CYP450 and P-gp inhibitory excipient could distinctively improve the oral availabilities of Rh1 compared to free drug or SME containing P-gp inhibitory excipient. No notable increase was observed between either SME for Rh2, suggesting that Rh2 undergoes P-gp-mediated efflux, but may not undergo distinct CYP450-mediated metabolism.

Supersaturable Self-Emulsifying Drug Delivery System of Krill Oil with Improved Oral Absorption and Hypotriglyceridemic Function

This study aimed to develop a supersaturable self-emulsifying drug delivery system (S-SEDDS) of krill oil (KO), a rich source of docosahexaenoic acid and eicosapentaenoic acid (EPA), to improve its hypotriglyceridemic function. S-SEDDS of KO (KO/S-SEDDS) was prepared by the addition of lysolecithin, glycerin, and hydroxypropyl methylcellulose (HPMC). Self-emulsifying drug delivery system of KO (KO/SEDDS) and KO with HPMC (KO/HPMC) were also prepared for comparison purposes. The physicochemical and pharmacokinetic properties of KO samples were characterized, and the hypotriglyceridemic function of KO/S-SEDDS was evaluated. Micronized droplets in KO/SEDDS and KO/S-SEDDS with a mean diameter of ca. 270 nm could be observed in comparison to KO and KO/HPMC. Both KO/HPMC and KO/S-SEDDS tended to enhance the dissolution behavior of KO, and the S-SEDDS formulation improved the dissolution behavior of KO as a result of micronized droplets and the addition of HPMC. KO/S-SEDDS (60 mg of EPA/kg) improved the oral absorption of KO based on the pharmacokinetic profiling of EPA, and repeated oral administration of KO/S-SEDDS (250 mg of KO kg^-1 day^-1) for 7 days had a potent hypotriglyceridemic effect on rats with corn-oil-induced hypertriglyceridemia compared to orally administered KO. On the basis of these findings, the S-SEDDS approach might be an efficacious dosage option to enhance the nutraceutical properties of KO.

Use of Resveratrol Self-Emulsifying Systems in T/C28a2 Cell Line as Beneficial Effectors in Cellular Uptake and Protection Against Oxidative Stress-Mediated Death

Osteoarthritis (OA) is the most prevalent rheumatic disease in the world. Although its etiology is still unknown, one of the key processes in OA progression and development is oxidative stress. In this context, resveratrol, a well-known anti-oxidant from the stilbene family, could be of particular interest in future OA therapeutic strategies. However, currently, because of its low bioavailability, use of resveratrol in human health is very limited. In this study, we tested two resveratrol self-emulsifying systems previously developed in our laboratory in order to determine if they could improve cellular uptake of resveratrol in a human immortalized chondrocytic cell line (T/C28a2) and enhance protection against oxidative stress. Our results showed that resveratrol self-emulsifying systems were able first to increase cellular tolerance towards resveratrol, and thus decrease resveratrol intrinsic cellular toxicity, allowing the use of higher concentrations, second, to increase resveratrol uptake in membrane and intracellular fractions, and finally, to improve protection against oxidative stress-mediated death in human immortalized chondrocytic cell line T/C28a2. These data suggest that new formulations of resveratrol could be considered as potential beneficial effectors in future OA treatments.

Development of self-microemulsifying drug delivery system for oral delivery of poorly water-soluble nutraceuticals

The objective of the study was to develop a self-microemulsifying drug delivery system (SMEDDS), also known as microemulsion preconcentrate, for oral delivery of five poorly water-soluble nutraceuticals or bioactive agents, namely, vitamin A, vitamin K2, coenzyme Q₁₀, quercetin and trans-resveratrol. The SMEDDS contained a 1:1 mixture (w/w) of Capmul MCM NF (a medium chain monoglyceride) and Captex 355 EP/NF (a medium chain triglyceride) as the hydrophobic lipid and Tween 80 (polysorbate 80) as the hydrophilic surfactant. The lipid and surfactant were mixed at 50:50 w/w ratio. All three of the SMEDDS components have GRAS or safe food additive status. The solubility of nutraceuticals was determined in Capmul MCM, Captex 355, Tween 80, and the SMEDDS (microemulsion preconcentrate mixture). The solubility values of vitamin A palmitate, vitamin K2, coenzyme Q₁₀, quercetin, and trans-resveratrol per g of SMEDDS were, respectively, 500, 12, 8, 56, and 87 mg. Appropriate formulations of nutraceuticals were prepared and filled into hard gelatin capsules. They were then subjected to in vitro dispersion testing using 250 mL of 0.01 N HCl in USP dissolution apparatus II. The dispersion test showed that all SMEDDS containing nutraceuticals dispersed spontaneously to form microemulsions after disintegration of capsule shells with globule size in the range of 25 to 200 nm. From all formulations, except that of vitamin K2, >80-90% nutraceuticals dispersed in 5-10 min and there was no precipitation of compounds during the test period of 120 min. Some variation in dispersion of vitamin K2 was observed due to the nature of the material used (vitamin K2 pre-adsorbed onto calcium phosphate). The present report provides a simple and organic cosolvent-free lipid-based SMEDDS for the oral delivery of poorly water-soluble nutraceuticals. Although a 50:50 w/w mixture of lipid to surfactant was used, the lipid content may be increased to 70:30 without compromising the formation of microemulsion.

Increased intestinal permeation and modulation of presystemic metabolism of resveratrol formulated into self-emulsifying drug delivery systems

Despite various beneficial biological properties, resveratrol lacks therapeutic applications because of poor bioavailability due to variable absorption and extensive metabolism. The present study aims at evaluating the capability of self-emulsifying drug delivery systems (SEDDS) to enhance resveratrol permeation across rat intestine and to modulate its presystemic metabolism. For that purpose, semi-solid (SS) and liquid (L) SEDDS were prepared and dispersed in an aqueous buffer to produce nanoemulsions (NE). The jejunal absorptive transepithelial fluxes (J_ms) of resveratrol elicited by these formulations (SS-NE and L-NE) and presystemic metabolization were determined on Ussing chambers. The absorptive fluxes through the intestinal epithelium from the nanoemulsions (J_ms=20.5±3.1μgh^-1cm^-2 SS-NE; 28.9±2.9μgh^-1cm^-2 L-NE) were significantly increased compared to an ethanolic control solution (J_ms=3.4±0.3μgh^-1cm^-2, p<0.05). No significant variations of conductance were observed after two hours of contact between the formulations and the mucosa. Simultaneously, the presystemic metabolization pattern was modified in the case of the nanoemulsions compared to the control solution. In conclusion, our data suggests that oil-in-water nanoemulsions prepared from SEDDS dispersions of medium-chain lipids could be promising formulations for enhancing oral delivery of resveratrol.

Preparation and In Vitro/In Vivo Evaluation of Puerarin Solid Self-Microemulsifying Drug Delivery System by Spherical Crystallization Technique

The aim of this work was to establish a method for preparing stable and controllable solid self-microemulsifying drug delivery system (S-SMEDDS) by spherical crystallization technique, which was explored for promoting the dissolution, oral bioavailability, and process efficiency. Solubility test, preparation of liquid self-microemulsifying drug delivery system (L-SMEDDS), and the obtained ternary phase diagrams test have been performed to screen and optimize the composition of LSMEDDS. The optimized formulation was used to prepare puerarin solid self-microemulsifying drug delivery system (Pue-SSMEDDS) by spherical crystallization technique. Droplet size and morphological analysis of the optimal Pue-SSMEDDS were determined to evaluate the final formulation. And the Pue-SSMEDDS was also assessed by flowability study, angle of repose, Carr's index, and flow velocity. Furthermore, the vitro dissolution and pharmacokinetic profile in vivo were analyzed. The study in vitro showed the Pue-SSMEDDS could disperse in the dispersion medium within 60 s and was spherical with the particle size of 19.66 nm and zeta potential of -28.3 mV. It could keep stable at low temperature and seal condition for 3 months. In vivo pharmacokinetic experiments of rats, the mean plasma concentration of self-microemulsion group was much higher than that of conventional tablets and could play a long-lasting efficacy, while there was no significant difference between the LSMEDDS and S-SMEDDS. The results suggested the potential of S-SMEDDS could improve the oral bioavailability of poorly water-soluble drug, such as puerarin.

Development and characterization of resveratrol nanoemulsions carrying dual-imaging agents

AIM

Delivery of the natural anti-inflammatory compound resveratrol with nanoemulsions can dramatically improve its tissue targeting, bioavailability and efficacy. Current assessment of resveratrol delivery efficacy is limited to indirect pharmacological measures. Molecular imaging solves this problem. Results/methodology: Nanoemulsions containing two complementary imaging agents, near-infrared dye and perfluoropolyether (PFPE), were developed and evaluated. Nanoemulsion effects on macrophage uptake, toxicity and NO production were also evaluated. The presence of PFPE did not affect nanoemulsion size, zeta potential, colloidal stability, drug loading or drug release.

CONCLUSION

PFPE nanoemulsions can be used in future studies to evaluate nanoemulsion biodistribution without interfering with resveratrol delivery and pharmacological outcomes. Developed nanoemulsions show promise as a versatile treatment strategy for cancer and other inflammatory diseases. [Formula: see text].

Resveratrol and Cardiovascular Diseases

The increased incidence of cardiovascular diseases (CVDs) has stimulated research for substances that could improve cardiovascular health. Among them, resveratrol (RES), a polyphenolic compound notably present in grapes and red wine, has been involved in the “French paradox”. RES is known for its antioxidant and anti-inflammatory properties and for its ability to upregulate endothelial NO synthase (eNOS). RES was able to scavenge ^•OH/O₂^•− and peroxyl radicals, which can limit the lipid peroxidation processes. Moreover, in bovine aortic endothelial cells (BAEC) under glucose-induced oxidative stress, RES restored the activity of dimethylargininedimethylaminohydrolase (DDAH), an enzyme that degrades an endogenous inhibitor of eNOS named asymmetric dimethylarginine (ADMA). Thus, RES could improve ^•NO availability and decrease the endothelial dysfunction observed in diabetes. Preclinical studies have made it possible to identify molecular targets (SIRT-1, AMPK, Nrf2, NFκB…); however, there are limited human clinical trials, and difficulties in the interpretation of results arise from the use of high-dose RES supplements in research studies, whereas low RES concentrations are present in red wine. The discussions on potential beneficial effects of RES in CVDs (atherosclerosis, hypertension, stroke, myocardial infarction, heart failure) should compare the results of preclinical studies with those of clinical trials.

Cyclodextrin-based nanosponges: a versatile platform for cancer nanotherapeutics development

Nanosponges (NSs) are a new age branched cyclodextrin (CD) polymeric systems exhibiting tremendous potential in pharmaceutical, agro science, and biomedical applications. Over the past decade, different varieties of NS based on the type of CD and the crosslinker have been developed tailored for specific applications. NS technology has been instrumental in achieving solubilization, stabilization, sustained release, enhancement of activity, permeability enhancement, protein delivery, ocular delivery, stimuli sensitive drug release, enhancement of bioavailability, etc. There is a major explosion of research in the area of NS-aided cancer therapeutics. A wide of anticancer molecules both from a pharmacological and physicochemical perspective have been developed as NS formulations by several groups including ours. Our objective in this review is to capture a systematic and comprehensive snapshot of the state-of-the-art of NS-aided cancer therapeutics reported so far. This review will provide an ideal platform for both the formulation scientists working on new polymeric/drug development and cancer biologists/scientists to understand the current nanotechnologies in CD-based NS-aided cancer therapeutics. The scope of the review is limited to small molecules and CD-based NS. The review covers in detail the problems associated with anticancer small molecules, and the solution provided by CD-based NS specifically for camptothecin, curcumin, paclitaxel, tamoxifen, resveratrol, quercetin, oxygen-NS, temozolomide, doxorubicin, and 5-Fluorouracil. WIREs Nanomed Nanobiotechnol 2016, 8:579-601. doi: 10.1002/wnan.1384 For further resources related to this article, please visit the WIREs website.

Recent trends in the development of nanophytobioactive compounds and delivery systems for their possible role in reducing oxidative stress in Parkinson's disease models

Oxidative stress plays a very critical role in neurodegenerative diseases, such as Parkinson's disease (PD), which is the second most common neurodegenerative disease among elderly people worldwide. Increasing evidence has suggested that phytobioactive compounds show enhanced benefits in cell and animal models of PD. Curcumin, resveratrol, ginsenosides, quercetin, and catechin are phyto-derived bioactive compounds with important roles in the prevention and treatment of PD. However, in vivo studies suggest that their concentrations are very low to cross blood-brain barrier thereby it limits bioavailability, stability, and dissolution at target sites in the brain. To overcome these problems, nanophytomedicine with the controlled size of 1-100 nm is used to maximize efficiency in the treatment of PD. Nanosizing of phytobioactive compounds enhances the permeability into the brain with maximized efficiency and stability. Several nanodelivery techniques, including solid lipid nanoparticles, nanostructured lipid carriers, nanoliposomes, and nanoniosomes can be used for controlled delivery of nanobioactive compounds to brain. Nanocompounds, such as ginsenosides (19.9 nm) synthesized using a nanoemulsion technique, showed enhanced bioavailability in the rat brain. Here, we discuss the most recent trends and applications in PD, including 1) the role of phytobioactive compounds in reducing oxidative stress and their bioavailability; 2) the role of nanotechnology in reducing oxidative stress during PD; 3) nanodelivery systems; and 4) various nanophytobioactive compounds and their role in PD.

A Self-microemulsifying Drug Delivery System (SMEDDS) for a Novel Medicative Compound Against Depression: a Preparation and Bioavailability Study in Rats

AJS is the code name of an untitled novel medicative compound synthesized by the Tasly Holding Group Company (Tianjin, China) based on the structure of cinnamamide, which is one of the Biopharmaceutics Classification System (BCS) class II drugs. The drug has better antidepressant effect, achieved by acting on the 5-hydroxytryptamine receptor. However, the therapeutic effects of the drug are compromised due to its poor water solubility and lower bioavailability. Herein, a self-microemulsifying drug delivery system (SMEDDS) was developed to improve its solubility and oral bioavailability. AJS-SMEDDS formulation was optimized in terms of drug solubility in the excipients, droplet size, stability, and drug precipitation using a pseudo-ternary diagram. The pharmacokinetic study was performed in rats, and the drug concentration in plasma samples was assayed using the high-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-MS/MS) method. The optimized formulation for SMEDDS has a composition of castor oil 24.5%, Labrasol 28.6%, Cremphor EL 40.8%, and Transcutol HP 2.7% (co-surfactant). No drug precipitation or phase separation was observed from the optimized formulation after 3 months of storing at 25°C. The droplet size of microemulsion formed by the optimized formulation was 26.08 ± 1.68 nm, and the zeta potential was -2.76 mV. The oral bioavailability of AJS-SMEDDS was increased by 3.4- and 35.9-fold, respectively, compared with the solid dispersion and cyclodextrin inclusion; meanwhile, the C max of AJS-SMEDDS was about 2- and 40-fold as great as the two controls, respectively. In summary, the present SMEDDS enhanced oral bioavailability of AJS and was a promising strategy to orally deliver the drug.

Development of an optimized hyaluronic acid-based lipidic nanoemulsion co-encapsulating two polyphenols for nose to brain delivery

The development of mucoadhesive lipidic nanoemulsion based on hyaluronic acid, co-encapsulating two polyphenols (resveratrol and curcumin) for the transnasal treatment of neurodegenerative diseases was attempted in the current manuscript. Nanoemulsions were prepared by the spontaneous emulsification method, and were characterized for their particle size, zeta potential, mucoadhesive strength and morphology. The selected formula was tested for its antioxidant potential, in vitro and ex vivo release of the two polyphenols, safety on nasal mucosa and in vivo quantification of the two drugs in rat brains. Its stability was tested by monitoring the change in particle size, zeta potential, drugs' content and antioxidant potential upon storage for 3 months. The optimized hyaluronic acid based nanoemulsion formula displayed a particle size of 115.2 ± 0.15 and a zeta potential of -23.9 ± 1.7. The formula displayed a spherical morphology and significantly higher mucoadhesive strength compared to its non mucoadhesive counterpart. In addition, the nanoemulsion was able to preserve the antioxidant ability of the two polyphenols and protect them from degradation. Diffusion controlled release of the two drugs was achievable till 6 hours, with an ex vivo flux across sheep nasal mucosa of 2.86 and 2.09 µg/cm(2)hr for resveratrol and curcumin, respectively. Moreover, the mucoadhesive nanoemulsion was safe on nasal mucosa and managed to increase the amounts of the two polypehnols in the brain (about 7 and 9 folds increase in AUC0-7 h for resveratrol and curcumin, respectively). Hyaluronic acid based lipidic nanoemulsion proved itself as a successful carrier enhancing the solubility, stability and brain targetability of polyphenols.

Resveratrol-loaded liposomes for topical treatment of the vaginal inflammation and infections

Resveratrol (RES), chemically known as 3,5,4'-trihydroxy-trans-stilbene, is a promising multi-targeted anti-oxidative and anti-inflammatory natural polyphenol. Preclinical studies showed its biological activities against the pathogens of sexually transmitted diseases causing vaginal inflammation and infections. Due to its low solubility and poor bioavailability, the optimal therapeutic uses are limited. Therefore, a clinically acceptable topical vaginal formulation of RES exhibiting optimal therapeutic effects is highly desirable. For this purpose, we prepared and optimized chitosan-coated liposomes with RES. The coated vesicles (mean diameter 200nm) entrapped up to 77% of RES, a sufficient load to assure required therapeutic outcome. In vitro drug release study showed the ability of liposomes to provide sustained release of RES. In vitro anti-oxidative activities of RES, namely DPPH and ABTS(•+) radicals scavenging assays, confirmed RES to be as potent as standard anti-oxidants, vitamins C and E. The anti-oxidative activities of RES and its corresponding liposomal formulation were also compared by measuring enhanced superoxide dismutase (SOD) activities in lipopolysaccharide (LPS)-induced J774A.1 cells. In vitro anti-inflammatory activities were compared by measuring nitric oxide (NO), tumor necrosis factor (TNF)-α and interleukin (IL)-1β production in LPS-induced J774A.1 cells. Liposomal RES was found to exhibit stronger anti-oxidative and anti-inflammatory activities than RES solution.

Pharmacokinetic Study and Optimal Formulation of New Anti-Parkinson Natural Compound Schisantherin A

Our recent studies showed that schisantherin A (StA) is a promising candidate for PD treatment, but the pharmacokinetic profile of StA is largely unknown. The effects of different formulations on the pharmacokinetics and bioavailability of StA were investigated by HPLC equipped with a vacuum degasser, a quaternary pump, a manual sampler, and an ultraviolet detector. The absolute bioavailability of StA in nanoemulsion formulation was significantly increased from 4.3% to 47.3%. To the best of our knowledge, this is the first report of absolute bioavailability for StA in rats and successful increase of bioavailability of StA by nanoemulsion formulation. The pharmacokinetic profiles of StA could be significantly improved by a safe nanoemulsion formulation. This study provides a successful example of advanced delivery system for improving the bioavailability of potential central nervous system (CNS) drug candidate with poor solubility. This novel approach could be an effective alternative solution to overcome the shortcomings of conventional poor drug delivery of CNS drugs. The results of present study not only indicate that StA has potential to be developed as a promising oral therapeutic agent for the management of PD but also shed light on novel way to improve bioavailability of PD drugs.

Stability and solubility of trans-resveratrol are strongly influenced by pH and temperature

Recently trans-resveratrol (trans-RSV) has received great attention due to its prophylactic and therapeutic properties. Its limited bioavailability provides compelling evidence of the need for more suitable formulations in order to attain better clinical effectiveness. Some physicochemical properties of trans-RSV are still unknown or research findings are contradictory. Therefore, this paper presents newly determined trans-RSV solubility and stability at various pH and temperatures, and the importance of such data for the studies of novel trans-RSV-loaded nanofibers. In acidic pH trans-RSV was stable, whereas its degradation started to increase exponentially above pH 6.8. Consequently, it is worthwhile to note that special consideration has to be dedicated to long dissolution testing or biological assays on cell lines in order to obtain relevant data. Measurements were done by validated UV/VIS spectroscopy, HPLC, and newly developed UPLC methods. Specificity was confirmed for HPLC and UPLC method, whereas UV/VIS spectroscopy resulted in false higher trans-RSV concentrations in conditions under which it was not stable (alkaline pH, light, increased temperature). The study is of interest because it draws attention to the importance of careful selected experimental conditions, their influence on the trans-RSV stability and the implications this has for formulation development, storage, and maintenance of therapeutic doses.

Involvement of the inhibition of intestinal glucuronidation in enhancing the oral bioavailability of resveratrol by labrasol containing nanoemulsions

Nanoemulsions have been developed for the oral delivery of poorly bioavailable phenolic compounds that are sensitive to intestinal glucuronidation. However, little is known about the contribution of UDP-glucuronosyltransferase (UGT) inhibitory excipients in nanoemulsions toward the inhibition of intestinal glucuronidation and the consequent enhanced bioavailability. In this study, Labrasol but not poloxamer 188 (F68) was found to inhibit the glucuronidation of resveratrol (RES), a model phenolic compound, in an inhibition assay with rat microsomes. Subsequently, two nanoemulsions, Lab-N and F68-N, were prepared with similar particle size distribution, zeta potentials, and entrapment efficiency by coemulsifying with Labrasol or F68, respectively. Although Lab-N exhibited inferior or comparable profiles of in vitro release, cellular uptake in Caco-2 cells, and lymphatic transport in rats to F68-N, the in vitro absorption study with everted sacs suggested that Labrasol containing formulations significantly and dose-dependently increased the transport of RES relative to free RES or F68-N by decreasing the amount of permeated metabolite, RES-3-glucuronide (RES-G). The in vivo pharmacokinetic experiments indicated that Lab-N exhibited increments in the maximum plasma concentration and the bioavailability of RES by 1098% and 560%, respectively, and significant decreases in those of RES-G, compared to F68-N. The overall results demonstrated that the improved oral bioavailability of RES by Lab-N was mainly attributable to the inhibition of intestinal glucuronidation by the presence of UGT inhibitory excipient.

Current nanotechnology approaches for the treatment and management of diabetic retinopathy

Diabetic retinopathy (DR) is a consequence of diabetes mellitus at the ocular level, leading to vision loss, and contributing to the decrease of patient's life quality. The biochemical and anatomic abnormalities that occur in DR are discussed in this review to better understand and manage the development of new therapeutic strategies. The use of new drug delivery systems based on nanoparticles (e.g. liposomes, dendrimers, cationic nanoemulsions, lipid and polymeric nanoparticles) is discussed along with the current traditional treatments, pointing out the advantages of the proposed nanomedicines to target this ocular disease. Despite the multifactorial nature of DR, which is not entirely understood, some strategies based on nanoparticles are being exploited for a more efficient drug delivery to the posterior segment of the eye. On the other hand, the use of some nanoparticles also seems to contribute to the development of DR symptoms (e.g. retinal neovascularization), which are also discussed in light of an efficient management of this ocular chronic disease.

Recent advances of resveratrol in nanostructured based delivery systems and in the management of HIV/AIDS

Resveratrol, a natural polyphenolic compound present in trees, in peanuts, in grapevines and exhibited multiple pharmacological activities. Extensive research in last two decades suggested that resveratrol possesses anti-inflammatory, anti-cancer, anti-viral, anti-amyloid, anti-arthritic and antioxidant properties. Some clinical reports have proposed that resveratrol might be a potential candidate for the prevention and/or treatment of HIV/AIDS and synergistically enhances the anti-HIV-1 activity. Resveratrol is not toxic to cells, and by itself reduces viral replication by 20% to 30%. With almost 12% of the world population suffering from HIV/AIDS including its resurgence in the developed world, better management of this global threat is highly desired. Further, various studies demonstrated several issues associated with resveratrol which account for its poor systemic bioavailability (almost zero) due to rapid and extensive first pass metabolism and existence of enterohepatic recirculation. In order to improve bioavailability and cellular uptake of resveratrol, various strategies have been adopted to date which includes resveratrol prodrug and the development of nanostructured delivery systems. Besides, nanostructured delivery systems are also known to inhibit the P-glycoprotein (P-gp) efflux, reduced metabolism by gut cytochrome P-450 enzymes, and circumnavigate the hepatic first-pass effect, facilitating absorption of drugs via intestinal lymphatic pathways. This review paper provides an updated bird's-eye view account on the publications and patents study on the recent novel approaches to deliver resveratrol in order to enhance oral bioavailability, overcome first pass metabolism and trounce enterohepatic recirculation to make resveratrol a therapeutically potent drug. Providing a relatively pithy overview, this paper thus presents recent advances of resveratrol for the treatment and prevention of HIV/AIDS.

Self-microemulsifying drug delivery system (SMEDDS)--challenges and road ahead

Self-microemulsifying drug delivery system (SMEDDS) has emerged as a vital strategy to formulate poor water soluble compounds for bioavailability enhancement. However, certain limitations are associated with SMEDDS formulations which include in vivo drug precipitation, formulation handling issues, limited lymphatic uptake, lack of predictive in vitro tests and oxidation of unsaturated fatty acids. These limitations restrict their potential usage. Inclusion of polymers or precipitation inhibitors within lipid based formulations helps to maintain drug supersaturation after dispersion. This, thereby, improves the bioavailability and reduces the variability on exposure. Also, formulating solid SMEDDS helps to overcome liquid handling and stability problems. Usage of medium chain triglycerides (MCT) and suitable antioxidants to minimize oxidation of unsaturated fatty acids are few of the steps to overcome the limitations associated with SMEDDS. The review discussed here, in detail, the limitations of SMEDDS and suitable measures that can be taken to overcome them.