Development of a quercetin-loaded nanostructured lipid carrier formulation for topical delivery

PLGA-PEG Nanoparticles Coated with Anti-CD45RO and Loaded with HDAC Plus Protease Inhibitors Activate Latent HIV and Inhibit Viral Spread

Activating HIV-1 proviruses in latent reservoirs combined with inhibiting viral spread might be an effective anti-HIV therapeutic strategy. Active specific delivery of therapeutic drugs into cells harboring latent HIV, without the use of viral vectors, is a critical challenge to this objective. In this study, nanoparticles of poly(lactic-co-glycolic acid)-polyethylene glycol diblock copolymers conjugated with anti-CD45RO antibody and loaded with the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) and/or protease inhibitor nelfinavir (Nel) were tested for activity against latent virus in vitro. Nanoparticles loaded with SAHA, Nel, and SAHA + Nel were characterized in terms of size, surface morphology, zeta potential, entrapment efficiency, drug release, and toxicity to ACH-2 cells. We show that SAHA- and SAHA + Nel-loaded nanoparticles can target latently infected CD4(+) T-cells and stimulate virus production. Moreover, nanoparticles loaded with SAHA + NEL were capable of both activating latent virus and inhibiting viral spread. Taken together, these data demonstrate the potential of this novel reagent for targeting and eliminating latent HIV reservoirs.

Nanostructured lipid carriers-based flurbiprofen gel after topical administration: acute skin irritation, pharmacodynamics, and percutaneous absorption mechanism

In order to assess the preliminary safety and effectiveness of nanostructured lipid carriers-based flurbiprofen gel (FP NLC-gel), the acute irritation test, in vivo pharmacodynamics evaluation and pharmacokinetic study were investigated after topical application. No dropsy and erythema were observed after continuous dosing 7 d of FP NLC-gel on the rabbit skin, and the xylene-induced ear drossy could be inhibited by FP NLC-gel at different dosages. The maximum concentration of FP in rats muscle was 2.03 μg/g and 1.55 μg/g after oral and topical administration, respectively. While the peak concentration in untreated muscle after topical administration was only 0.37 μg/mL. And at any time, following topical administration the mean muscle-plasma concentration ratio Cmuscle/CPlasma was obviously higher than that following oral administration. Results indicated that FP could directly penetrate into the subcutaneous muscle tissue from the administration site. Thus, the developed FP NLC-gel could be a safe and effective vehicle for topical delivery of FP.

Quercetin prevents adipogenesis by regulation of transcriptional factors and lipases in OP9 cells

With the industrialization of society, the increase in the prevalence of obesity and metabolic disorders has become an important health concern in a number of countries. Quercetin (3,30,40,5,7-pentahydroxyflavone) is well known as a bioactive flavonoid in a variety of biological resources. The aim of the present study was to explore the machanisms responsible for the anti-adipogenic activity of quercetin and its effects on the lipolysis in OP9 mouse stromal cells which rapidly differentiate into adipocytes. The differentiation of OP9 cells into adipocytes was evaluated by the measurement of lipid accumulation by Oil Red O (ORO) staining; lipid accumulation was significantly impaired by treatment with quercetin. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis were used to measure the expression levels of CCAAT/enhancer binding protein α (C/EBPα), proliferator-activated receptor γ (PPARγ), sterol regulatory element-binding protein-1 (SREBP-1) and fatty acid synthase (FAS). The mRNA expression levels of lipases, such as adipose triglyceride lipase (ATGL), hormone sensitive lipase (HSL) and lipoprotein lipase (LPL) were also measured by RT-PCR. Quercetin significantly decreased the expression of transcription factors, including C/EBPα, PPARγ and SREBP-1c both at the protein and mRNA level. The results from the present study demonstrate that quercetin prevents adipogenesis by upregulating ATGL and HSL expression and downregulating FAS, LPL and adipocyte fatty acid-binding protein (aP2) expression, as well as the expression of transcription factors. Our data suggest that quercetin has therapeutic potential by regulating the expression of transcriptional factors and enzymes associated with adipogenesis.

Parameters and characteristics governing cellular internalization and trans-barrier trafficking of nanostructures

Cellular internalization and trans-barrier transport of nanoparticles can be manipulated on the basis of the physicochemical and mechanical characteristics of nanoparticles. Research has shown that these factors significantly influence the uptake of nanoparticles. Dictating these characteristics allows for the control of the rate and extent of cellular uptake, as well as delivering the drug-loaded nanosystem intra-cellularly, which is imperative for drugs that require a specific cellular level to exert their effects. Additionally, physicochemical characteristics of the nanoparticles should be optimal for the nanosystem to bypass the natural restricting phenomena of the body and act therapeutically at the targeted site. The factors at the focal point of emerging smart nanomedicines include nanoparticle size, surface charge, shape, hydrophobicity, surface chemistry, and even protein and ligand conjugates. Hence, this review discusses the mechanism of internalization of nanoparticles and ideal nanoparticle characteristics that allow them to evade the biological barriers in order to achieve optimal cellular uptake in different organ systems. Identifying these parameters assists with the progression of nanomedicine as an outstanding vector of pharmaceuticals.

In vitro and in vivo study of Baicalin-loaded mixed micelles for oral delivery

The aim of this work was to research the potential functions and the mechanism of absorption of the baicalin (BC)-loaded micelle system that contained Pluronic P123 copolymer (P123) and sodium taurocholate (ST) as carrier materials via oral delivery. Based on the numerous advantages of oral administration, such as cost-effectiveness, flexible and accommodated dosing regimen, and improved compliance for patients, the ST-P123-MMs system would be evaluated as oral delivery vehicle of BC. In this study, X-ray powder diffractometer analysis confirmed the phase change of BC after being incorporated in mixed micelles. The release study in simulated gastric fluid/simulated intestinal fluid exhibited that BC-loaded ST-P123-MMs presented a sustained drug release behavior. Compared with coumarin-6 solution, higher cellar uptake efficiency was achieved for coumarin-6 loaded ST-P123-MMs towards Caco-2 cell lines. The in situ perfusion test in rat indicated that the absorption of BC-loaded ST-P123-MMs in intestinal tract was stronger than BC solution. After oral administration, the Cmax and AUC of BC-loaded ST-P123-MMs were 1.77 times and 1.54 times as high as those of BC suspension in rat, respectively. Promisingly, the formulated BC exhibited a prolonged circulation time with the oral bioavailability increased to 1.54-fold compared with the control group. These results all suggested that P123 and ST mixed micelles could serve as a promising approach to oral administration of BC.

Potential of Nanomaterials as Movers and Packers for Drug Molecules

As the development of nanotechnology has extended to the world of biomolecules, a revolution has occurred in the design and assembly of nanomaterials for drug delivery with a significant potential to impact drug efficacy and patient outcomes. Currently a number of nanomaterials are under investigation for their suitability as sustained, controlled and targeted drug carriers. Leading edge of the rapidly developing nanosciences is the development and assessment of these nanomaterials, with specific physicochemical properties different from their larger/ bulk counterparts, as vehicles for transport of small and large drug molecules. The characteristics such as size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility, can greatly influence interactions of these nanostructured systems or carriers with biomembranes and cells. The selectivity and reactivity achieved due to the very small size assigns these systems with a wide spectrum of applications. In this review, nanomaterials are considered in terms of the physical attributes or pharmaceutical effects allocated by them to the all-inclusive carrier or vehicle system (s). However we will limit our discussion to lipidic and polymeric nanomaterials, the two most commonly promoted, and safe nanosystems for delivery of both, the chemical or small molecular entities (SME) and the macromolecules including genes and siRNA.Contents of Paper

Skin delivery aspects of benzoyl peroxide-loaded solid lipid nanoparticles for acne treatment

Background: Benzoyl peroxide (BPO) has been a mainstay of topical acne treatment for years. However, is frequently accompanied by cutaneous irritation and erythema. To reduce these side effects many novel drug delivery systems have been developed in the past, of which solid lipid nanoparticles (SLN) demonstrate clear dominance. Hence, we developed a facile method to prepare stable SLN of BPO and evaluated their anti-bacterial activity. Results: BPO-SLN optimized using 23 full factorial design provided high occlusion factor, low permeation rate, increased drug deposition, reduced skin irritation and strong anti-bacterial activity in contrast with marketed product. Conclusion: Desired goals were achieved by factorial design approach in shortest possible time with minimum number of experiments. The developed BPO-SLN system provided controlled drug release, thereby reducing the well-known side effects.

Overview of metabolism and bioavailability enhancement of polyphenols

A proper diet is one of major factors contributing to good health and is directly related to general condition of the organism. Phenolic compounds are abundant in foods and beverages (fresh and processed fruits and vegetables, leguminous plants, cereals, herbs, spices, tea, coffee, wine, beer) and their pleiotropic biological activities result in numerous health beneficial effects. On the other hand, high reactivity and very large diversity in terms of structure and molecular weight renders polyphenols one of the most difficult groups of compounds to investigate, as evidenced by ambiguous and sometimes contradictory results of many studies. Furthermore, phenolics undergo metabolic transformations, which significantly change their biological activities. Here, we discuss some aspects of metabolism and absorption of phenolic compounds. On the basis of information reported in the literature as well as in summaries of clinical trials and patent applications, we also give an overview of strategies for enhancing their bioavailability.

Nanotechnology-based drug delivery systems and herbal medicines: a review

Herbal medicines have been widely used around the world since ancient times. The advancement of phytochemical and phytopharmacological sciences has enabled elucidation of the composition and biological activities of several medicinal plant products. The effectiveness of many species of medicinal plants depends on the supply of active compounds. Most of the biologically active constituents of extracts, such as flavonoids, tannins, and terpenoids, are highly soluble in water, but have low absorption, because they are unable to cross the lipid membranes of the cells, have excessively high molecular size, or are poorly absorbed, resulting in loss of bioavailability and efficacy. Some extracts are not used clinically because of these obstacles. It has been widely proposed to combine herbal medicine with nanotechnology, because nanostructured systems might be able to potentiate the action of plant extracts, reducing the required dose and side effects, and improving activity. Nanosystems can deliver the active constituent at a sufficient concentration during the entire treatment period, directing it to the desired site of action. Conventional treatments do not meet these requirements. The purpose of this study is to review nanotechnology-based drug delivery systems and herbal medicines.

Topical anti-inflammatory potential of quercetin in lipid-based nanosystems: in vivo and in vitro evaluation

PURPOSE

To develop quercetin-loaded phospholipid vesicles, namely liposomes and PEVs (Penetration Enhancer-containing Vesicles), and to investigate their efficacy on TPA-induced skin inflammation.

METHODS

Vesicles were made from a mixture of phospholipids, quercetin and polyethylene glycol 400 (PEG), specifically added to increase drug solubility and penetration through the skin. Vesicle morphology and self-assembly were probed by Cryo-Transmission Electron Microscopy and Small/Wide Angle X-ray Scattering, as well as the main physico-chemical features by Light Scattering. The anti-inflammatory efficacy of quercetin nanovesicles was assessed in vivo on TPA-treated mice dorsal skin by the determination of two biomarkers: oedema formation and myeloperoxidase activity. The uptake of vesicles by 3T3 fibroblasts was also evaluated.

RESULTS

Small spherical vesicles were produced. Their size and lamellarity was strongly influenced by the PEG content (0%, 5%, 10% v/v). The administration of vesicular quercetin on TPA-inflamed skin resulted in an amelioration of the tissue damage, with a noticeable attenuation of oedema and leukocyte infiltration, especially using 5% PEG-PEVs, as also confirmed by confocal microscopy. In vitro studies disclosed a massive uptake and diffusion of PEVs in dermal fibroblasts.

CONCLUSIONS

The proposed approach based on quercetin vesicular formulations may be of value in the treatment of inflammatory skin disorders.

Characterization and biodistribution in vivo of quercetin-loaded cationic nanostructured lipid carriers

Nanobiotechnology has been recently viewed as a promising strategy to improve therapy efficacy by promoting the accumulation of hydrophobic bioactive compounds in tissues. The aim of present study was to formulate a novel quercetin-loaded cationic nanostructured lipid carriers (QR-CNLC) and to evaluate its biodistribution in vivo after oral administration. QR-CNLC were prepared by emulsifying at high temperature and subsequent solidifying at low temperature using various functional ingredients, and its characteristics, including physical index, release profile in vitro, and tissue distribution in vivo, were investigated. The results demonstrated that QR-CNLC exhibited an average particle size 126.6 nm, a zeta potential of 40.5 mV and 89.3% entrapment efficiency. QR-CNLC performed slower release compared with quercetin solution in vitro. QR-CNLC showed higher AUC (area under tissue concentration-time curve) value and higher Cmax value in lung, liver and kidney compared with control group. The value of relative intake rate (re) for lung, liver and kidney was 1.57, 1.51 and 1.68, respectively, which revealed that quercetin can be significantly accumulated in lung, kidney and liver after oral administration of QR-CNLC compared with quercetin suspension. In conclusion, cationic nanostructured lipid carriers may be an attractive nanocarrier system for oral delivery of hydrophobic functional components.

Application of nanotechnology in improving bioavailability and bioactivity of diet-derived phytochemicals

Nanotechnology is an innovative approach that has potential applications in nutraceutical research. Phytochemicals have promising potential for maintaining and promoting health, as well as preventing and potentially treating some diseases. However, the generally low solubility, stability, bioavailability and target specificity, together with the side effects seen when used at high levels, have limited their application. Indeed, nanoparticles can increase solubility and stability of phytochemicals, enhance their absorption, protect them from premature degradation in the body and prolong their circulation time. Moreover, these nanoparticles exhibit high differential uptake efficiency in the target cells (or tissue) over normal cells (or tissue) through preventing them from prematurely interacting with the biological environment, enhanced permeation and retention effect in disease tissues and improving their cellular uptake, resulting in decreased toxicity, In this review, we outline the commonly used biocompatible and biodegradable nanoparticles including liposomes, emulsions, solid lipid nanoparticles, nanostructured lipid carriers, micelles and poly(lactic-co-glycolic acid) nanoparticles. We then summarize studies that have used these nanoparticles as carriers for epigallocatechin gallate, quercetin, resveratrol and curcumin administration to enhance their aqueous solubility, stability, bioavailability, target specificity and bioactivities.

Preparation, characterization, and in vivo pharmacokinetics of nanostructured lipid carriers loaded with oleanolic acid and gentiopicrin

Background

The purpose of this work was to develop nanostructured lipid carriers (NLCs) loaded simultaneously with oleanolic acid and gentiopicrin.

Methods

An aqueous dispersion of NLCs was prepared successfully using a film-ultrasonic method, with glycerin monostearate as the solid lipid and oleic acid as the liquid lipid. Poloxamer 188 was used as the surfactant. A central composite design was used to optimize the technologic parameters. The characteristics of the NLCs were then investigated.

Results

The encapsulation efficiency was 48.34% ± 2.76%, drug loading was 8.06% ± 0.42%, particle size was 111.0 ± 1.56 nm, polydispersity index was 0.287 ± 0.01, and zeta potential was −23.8 ± 0.36 mV for the optimized NLCs. The other physicochemical properties were characterized by transmission electron microscopy and differential scanning calorimetry. Drug release followed first-order kinetics and release studies confirmed that oleanolic acid and gentiopicrin fitted a sustained-release model. Compared with NLCs loaded with oleanolic acid or gentiopicrin alone, NLCs loaded with both oleanolic acid and gentiopicrin produced drug concentrations which persisted for a significantly longer time in plasma, with a linear decrement following second-order kinetics. Aspartate and alanine aminotransferase levels were significantly lower on exposure to NLCs loaded with both oleanolic acid and gentiopicrin than in negative controls.

Conclusion

The results of this study confirm that oleanolic acid and gentiopicrin can be loaded simultaneously into NLCs. Compared with oleanolic acid and gentiopicrin loaded alone, sustained release and protective effects against hepatic injury were observed using NLCs loaded with both oleanolic acid and gentiopicrin.

Formulation design, preparation, and in vitro and in vivo characterizations of β-Elemene-loaded nanostructured lipid carriers

In the present study, nanostructured lipid carriers (NLCs) were prepared and optimized for the intravenous delivery of β-Elemene (β-E). Aqueous dispersions of NLCs were successfully prepared by high-pressure homogenization method using glycerol monostearate as the solid lipid and a mixture of Maisine 35-1 and Labrafil M1944 CS as the liquid lipid. The results revealed that the morphology of the NLCs was spheroidal. The particle size, zeta potential, and entrapment efficiency (EE) for the optimized formulation were observed as 138.9 nm, -20.2 mV, and 82.11%, respectively. X-ray diffraction analysis revealed the formation of less ordered structures in the inner core of the NLC particles. Moreover, the β-E-loaded NLCs were also less irritating and less toxic compared to Elemene injection. In addition, β-E-NLCs showed a significantly higher bioavailability and anti-tumor efficacy than Elemene injection. Taken together, our data indicate that the β-E-NLCs described in this study are well-suited for the intravenous delivery of β-E.

Delivering flavonoids into solid tumors using nanotechnologies

INTRODUCTION

Long-term epidemiological studies have demonstrated that regular ingestion of flavonoids contained in dietary sources is associated with a reduced risk for many chronic diseases including cancer. However, although flavonoids are largely consumed in the diet and high concentrations may exist in the intestine after oral administration, the plasma/tissue concentrations of flavonoids are lower than their effective therapeutic doses due to poor bioavailability, resulting in the limited efficacy of flavonoids in various clinical studies. Therefore, the application of nanotechnology to deliver flavonoids to tumor sites has received considerable attention in recent years.

AREAS COVERED

In this review, after a general review of the potential benefits of flavonoids in cancer therapy and several key factors affecting their bioavailability, the current efforts in improving the delivery efficacy of promising candidates that are particularly important in the human diet, namely quercetin, epigallocatechin-3-gallate (EGCG) and genistein were focused on. Finally, the challenges of developing flavonoid delivery systems that improve flavonoid bioavailability and their anticancer therapy potentials were summarized.

EXPERT OPINION

The design of suitable molecular carriers for flavonoids is an area of research that is in rapid progress. A large number of unheeded promising favonoids are suffering from poor in vivo parameters, their potential benefits deserves further research. Furthermore, more effort should be placed on developing active targeting systems, evaluating the efficacy and toxicity of novel flavonoid delivery systems through small and large scale clinical trials.

Formulation optimization and topical delivery of quercetin from solid lipid based nanosystems

The presence of large amounts of reactive oxygen species (ROS) leads to oxidative stress that can damage cell membranes, lead to DNA breakage and cause inactivation of free radical scavenger enzymes, eventually resulting in skin damage. Quercetin is a natural flavonoid that has been shown to have the highest anti-radical activity, along with the ability to act as a scavenger of free radicals and an inhibitor of lipid peroxidation. In this research work, a solvent-free solid lipid based nanosystem has been developed and evaluated for topical delivery of quercetin. Systematic screening of the formulation and process parameters led to the development of a solid lipid (glyceryl dibehenate) based nanosystem using a probe ultrasonication method. The selected variant demonstrated good physical stability for up to 8 weeks at 2-8 °C. Transmission electron microscopy (TEM) images showed spherical particles in the nanometer range. In vitro release studies showed biphasic release of quercetin from the SLN formulation, with an initial burst release followed by prolonged release for up to 24h. In vitro permeation studies using full thickness human skin showed higher amounts of quercetin to be localized within the skin compared to a control formulation with particles in the micrometer range. Such accumulation of quercetin in the skin is highly desirable since the efficacy of quercetin in delaying ultra-violet radiation mediated cell damage and eventual necrosis mainly occurs in the epidermis.

Preparation and characterization of lipid based nanosystems for topical delivery of quercetin

The main objective of this study was to evaluate the potential of lipid nanosystems for topical delivery of the naturally occurring flavonoid quercetin. These lipid based nanosystems were manufactured using a solvent free probe ultrasonication process. Formulation factors such as the nature of the lipid (solid/combination of solid and liquid) in solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLC) systems and drug loading were evaluated to produce an optimum formulation with adequate physical stability for up to 14 weeks at 2-8°C. The mean particle size of the optimized formulation was around 282 nm, with a zeta potential value of -36.57 ± 2.67 mV, indicating the formation of a stable system. Release studies showed a biphasic release profile, characterized by an initial burst release followed by a more controlled release pattern from both SLN and NLC systems. The NLC system showed the highest improvement in topical delivery of quercetin manifested by the amount of quercetin retained in full thickness human skin, compared to a control formulation with similar composition and particle size in the micrometer range. This study demonstrated the feasibility of nanostructured lipid carrier systems for improved topical delivery of quercetin.

Nanostructured lipid carriers (NLC) based topical gel of flurbiprofen: design, characterization and in vivo evaluation

Nanostructured lipid carriers (NLC)-based gel was developed as potential topical system for flurbiprofen (FP) topical delivery. The characterizations of the prepared semisolid formulation for topical application on skin were assessed by means of particle size distribution, zeta potential analysis, X-ray analysis, in vitro percutaneous penetration, rheological study, skin irritation test, in vivo pharmacodynamic evaluation and in vivo pharmacokinetic study. The NLC remained within the colloidal range and it was uniformly dispersed after suitably gelled by carbopol preparation. It was indicated in vitro permeation studies through rat skin that FP-NLC-gel had a more pronounced permeation profile compared with that of FP-loaded common gel. Pseudoplastic flows with thixotropy were obtained for all NLC-gels after storage at three different temperatures. No oedema and erythema were observed after administration of FP-NLC-gel on the rabbit skin, and the ovalbumin induced rat paw edema could be inhibited by the gel. The maximum concentration in plasma was 29.44 μg/ml and 2.49 μg/ml after oral and topical administration, respectively. While the amount of drug accumulated in skin after topical application was much higher than oral application. In conclusion, NLC-based gel could be a promising vehicle for topical delivery of FP.