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

Monoolein aqueous dispersions as a delivery system for quercetin

This study describes the preparation, characterization and in vitro release of monoolein aqueous dispersions (MAD) encapsulating quercetin (QT). As emulsifier, sodium cholate was employed at two different concentrations, namely 0.15% and 0.25% with respect to the total weight of the formulation. Cryogenic Transmission electron microscopy and X-ray analysis indicated that MAD015 are a mixture of vesicles and cubic structures, whilst MAD025 are mainly characterized by unilamellar vesicular structures. Photon correlation spectroscopy (PCS) and Sedimentation Field Flow Fractionation (SdFFF) showed a MAD size higher than 300 nm that over 100 days from analysis reduces up to 200 nm. In vitro Franz cell experiments showed that the two systems had a similar behaviour in the release of QT. Experiments on antioxidant activity of MAD containing QT demonstrated that their activity parallel with the content of encapsulated QT within the MAD formulations produced. Taken together these results allow us to conclude that MAD can be potentially proposed for the delivery of QT.

Advances in the design of solid lipid nanoparticles and nanostructured lipid carriers for targeting brain diseases

Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) comprise a category of versatile drug delivery systems that have been used in the biomedical field for >25years. SLNs and NLCs have been used for the treatment of various diseases including cardiovascular and cerebrovascular, and are considered a standard treatment for the latter, due to their inherent ability to cross the blood brain barrier (BBB). In this review, a presentation of the most important brain diseases (brain cancer, ischemic stroke, Alzheimer's disease, Parkinson's disease and multiple sclerosis) is approached, followed by the basic fabrication techniques of SLNs and NLCs. A detailed description of the reported studies of the last seven years, of active and passive targeting SLNs and NLCs for the treatment of glioblastoma multiforme and of other brain cancers, as well as for the treatment of neurodegenerative diseases is also carried out. Finally, a brief description of the advantages, the disadvantages, and the future perspectives in the use of these nanocarriers is reported, aiming at giving an insight of the limitations that have to be overcome in order to result in a delivery system with high therapeutic efficacy and without the limitations of the existing nano-systems.

Production of Cornstarch Granules Enriched with Quercetin Liposomes by Aggregation of Particulate Binary Mixtures Using High Shear Process

Liposomes are colloidal structures capable of encapsulating, protecting, and releasing hydrophobic bioctives, as flavonoids. Quercetin is a flavonoid with high antioxidant activity that provides benefits to health. The wet-agglomeration processes in high-shear equipment are useful to produce granules from binary mixtures, obtaining a powder with homogeneous composition and without segregation or elutriation of fine particles. In this study, the binary mixtures containing microparticles of native cornstarch and nanoparticles of quercetin liposomes were aggregated in high-shear batches, using maltodextrin solution as binder agent. The cornstarch was enriched by agglomeration with 8%, 22%, and 30% (w/w) of quercetin-loaded lyophilized liposomes and the physical properties were evaluated. The moisture of all formulations showed similar values ranging from 4.42% to 4.57%. The values of hygroscopicity (g adsorbed water/100 g of dry matter) indicated the lyophilized liposomes were able to decrease the capacity of the agglomerated cornstarch to absorb water, decreasing the possibility of microbiological contamination. The addition of quercetin-loaded lyophilized liposomes improved the flowability and turned the powder (agglomerated cornstarch) less cohesive. The pasting properties of enriched agglomerated cornstarch decreased the pasting temperature about 10 °C, and the cornstarch agglomerated with 8% (w/w) of quercetin-loaded lyophilized liposomes showed no significance difference in the peak viscosity. Agglomeration of cornstarch with more than 8% (w/w) lyophilized liposomes decreased the tendency of starch to retrograde, which is very interesting for food products which requires low levels of retrogradation of granules for their stability.

PRACTICAL APPLICATION

This study is an unprecedent association of 2 technologies, nanoencapsulation and wet agglomeration, here used together to enrich cornstarch with quercetin. The agglomeration process was used to obtain granules of cornstarch, an ingredient extremely used in the food industry, enriched with quercetin-loaded lyophilized liposomes. The goals were both the improvement of the nutritional quality and the increase of the added value of the cornstarch.

Novel nanosystems for the treatment of ocular inflammation: Current paradigms and future research directions

Ocular discomforts involve anterior/posterior-segment diseases, symptomatic distress and associated inflammations and severe retinal disorders. Conventionally, the formulations such as eye drops, eye solutions, eye ointments and lotions, etc. were used as modalities to attain relief from such ocular discomforts. However, eye allows limited access to these traditional formulations due to its unique anatomical structure and dynamic ocular environment and therefore calls for improvement in disease intervention. To address these challenges, development of nanotechnology based nanomedicines and novel nanosystems (liposomes, cubosomes, polymeric and lipidic nanoparticles, nanoemulsions, spanlastics and nano micelles) are currently in progress (some of them are already marketed such as Eye-logic liposomal eye spray@Naturalife, Ireland). Today, it is one of the central concept in designing more accessible formulations for deeper segments of the eyes. These nanosystems has largely enabled the availability of medicaments at required site in a required concentration without inversely affecting the eye tissues; and therefore, attaining the excessive considerations from the formulation scientists and pharmacologists worldwide. The entrapment of drugs, genes, and proteins inside these novel systems is the basis that works at the bio-molecular level bestows greater potential to eradicate disease causatives. In this review, we highlighted the recent attempts of nanotechnology-based systems for treating and managing various ocular ailments. The progress described herein may pave the way to new, highly effective and vital ocular nanosystems.

Polymeric drug delivery systems for intraoral site-specific chemoprevention of oral cancer

Oral cancer is among the most prevalent cancers in the world. Moreover, it is one of the major health problems and causes of death in many regions of the world. The traditional treatment modalities include surgical removal, radiation therapy, systemic chemotherapy, or a combination of these methods. In recent decades, there has been significant interest in intraoral site-specific chemoprevention via local drug delivery using polymeric systems. Because of its easy accessibility and clear visibility, the oral mucosa is amenable for local drug delivery. A variety of polymeric systems-such as gels, tablets, films, patches, injectable systems (e.g., millicylindrical implants, microparticles, and in situ-forming depots), and nanosized carriers (e.g., polymeric nanoparticles, nanofibers, polymer-drug conjugates, polymeric micelles, nanoliposomes, nanoemulsions, and polymersomes)-have been developed and evaluated for the local delivery of natural and synthetic chemopreventive agents. The findings of in vitro, ex vivo, and in vivo studies and the positive outcome of clinical trials demonstrate that intraoral site-specific drug delivery is an attractive, highly effective and patient-friendly strategy for the management of oral cancer. Intraoral site-specific drug delivery provides unique therapeutic advantages when compared to systemic chemotherapy. Moreover, intraoral drug delivery systems are self-administrable and can be removed when needed, increasing patient compliance. This article covers important aspects and advances related to the design, development, and efficacy of polymeric systems for intraoral site-specific drug delivery. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1383-1413, 2018.

Phytobioactive compound-based nanodelivery systems for the treatment of type 2 diabetes mellitus - current status

Type 2 diabetes mellitus (T2DM) is a major chronic disease that is prevalent worldwide, and it is characterized by an increase in blood glucose, disturbances in the metabolism, and alteration in insulin secretion. Nowadays, food-based therapy has become an important treatment mode for type 2 diabetes, and phytobioactive compounds have gained an increasing amount of attention to this end because they have an effect on multiple biological functions, including the sustained secretion of insulin and regeneration of pancreatic islets cells. However, the poor solubility and lower permeability of these phyto products results in a loss of bioactivity during processing and oral delivery, leading to a significant reduction in the bioavailability of phytobioactive compounds to treat T2DM. Recently, nanotechnological systems have been developed for use as various types of carrier systems to improve the delivery of bioactive compounds and thus obtain a greater bioavailability. Furthermore, carrier systems in most nanodelivery systems are highly biocompatible, with nonimmunologic behavior, a high degree of biodegradability, and greater mucoadhesive strength. Therefore, this review focuses on the various types of nanodelivery systems that can be used for phytobioactive compounds in treating T2DM with greater antidiabetic effects. There is also additional focus on improving the effects of various phytobioactive compounds through nanotechnological delivery to ensure a highly efficient treatment of type 2 diabetes.

Promises of a biocompatible nanocarrier in improved brain delivery of quercetin: Biochemical, pharmacokinetic and biodistribution evidences

In various neurological disorders, antioxidants are frequently prescribed along with the specific treatment modalities. One such promising natural flavonoid is quercetin, offering better outcomes than established vitamins E and C. Though with immense promises, various challenges like poor oral-bioavailability (<2%), extensive first-pass metabolism, poor brain permeability, hydrophobic nature and physiological pH instability hinder its proper usage. Hence, it was planned to prepare quercetin-loaded nano lipidic carriers (NLCs) employing biocompatible components like phospholipids and tocopherol acetate for enhanced brain delivery. The outcomes were also compared with solid lipid nanoparticles (SLNs) of comparable composition. Both the nanocolloids offered better drug loading and controlled drug release with appreciable stability. In vitro antioxidant performance was improved after encapsulation in nanoparticles and the nanoparticles were substantially uptaken by Caco-2 cells. The difference in outcomes was vivid in pharmacokinetic studies, where nanoparticles, esp. NLCs substantially enhanced the relative bioavailability (approx. 6 folds), biological residence (2.5 times) and appreciably retarded the drug clearance (approx. 6 folds). On the other hand, both nanoparticles were able to substantially deliver the drug to brain. NLCs were observed to enhance the brain permeability of drug in a noticeable manner. In Conclusion, SLNs/NLCs can offer a better-platform for brain-delivery of quercetin.

Nanostructured lipid carriers: versatile oral delivery vehicle

Oral delivery is the most accepted and economical route for drug administration and leads to substantial reduction in dosing frequency. However, this route still remains a challenge for the pharmaceutical industry due to poorly soluble and permeable drugs leading to poor oral bioavailability. Incorporating bioactives into nanostructured lipid carriers (NLCs) has helped in boosting their therapeutic functionality and prolonged release from these carrier systems thus providing improved pharmacokinetic parameters. The present review provides an overview of noteworthy studies reporting impending benefits of NLCs in oral delivery and highlights recent advancements for developing engineered NLCs either by conjugating polymers over their surface or modifying their charge to overcome the mucosal barrier of GI tract for active transport across intestinal membrane.

Lay abstract: Oral administration of drugs is considered to be a convenient route; however, various drugs that are insoluble in water or unable to permeate across GI tract membrane cannot be delivered by this route. To deliver them effectively, various lipid carriers have been widely explored by researchers. Lipid carriers encapsulate drug inside them and deliver them effectively via the oral route. Also, encapsulation of drug protects them from degradation inside GI tract and safely delivers them to the site of action. This review summarizes application of lipid carriers, in other words, nanostructured lipid carriers, in eradicating these problems, with suitable examples.

Heterogeneous polymer composite nanoparticles loaded in situ gel for controlled release intra-vaginal therapy of genital herpes

Herpes simplex virus causes serious and contagious genital infections in high percentage of female population world-wide. Acyclovir is a clinically successful antiviral molecule till date, in-spite of limitations as poor solubility, low half-life, reduced oral bioavailability and side effects at higher doses. In the present work, controlled release in situ gelling system loaded with polymeric nanoparticles of acyclovir containing a dose of drug equivalent to 105mg/day has been developed. The formulation containing drug loaded polyvinyl pyrrolidone-Eudragit RSPO hybrid polymeric nanoparticles (Size ∼99±3nm, Zeta ∼+26.1±1.5mV) in 15% Pluronic F-127 gel exhibited improved permeability through vaginal membrane (KP=2.20±0.19×10(-6)cm/s). The nanoparticles showed enhanced viability for vaginal epithelial cell lines up to concentration of 100-250μg/mL. The formulation was evaluated for bioavailability and biodistribution through intra-vaginal administration in rat models. The nanoparticle in situ gel formulation maintained an average therapeutic drug level of 0.6±0.2μg/mL in plasma for 24h. Significant improvement in mean residence time of the drug (12.52±1.12h) was observed with a two-fold increase in the relative bioavailability (AUC0-24h=14.92±2.44μgh/mL) compared to that of the pure drug (7.18±1.79μgh/mL). The tissue distribution was 2-3 folds higher in animals treated with nanoparticles in situ gel compared to that of pure drug. Sustained release of drug in vivo was demonstrated, ensuring the suitability of the formulation for clinical therapy in female population.

Dermal quercetin smartCrystals®: Formulation development, antioxidant activity and cellular safety

Flavonoids are natural plant pigments, which possess high antioxidative and antiradical activities. However, their poor water solubility led to a limited bioavailability. To overcome this major hurdle, quercetin nanocrystals were produced implementing smartCrystals® technology. This process combines bead milling and subsequent high-pressure homogenization at relatively low pressure (300bar). To test the possibility to develop a dermal formulation from quercetin smartCrystals®, quercetin nanosuspensions were admixed to Lutrol® F127 and hydroxythylcellulose nonionic gels. The physicochemical properties (morphology, size and charge), saturation solubility, dissolution velocity and the antioxidant properties (DPPH assay) as well as the cellular interaction of the produced quercetin smartCrystals® were studied and compared to crude quercetin powder. Quercetin smartCrystals® showed a strong increase in the saturation solubility and the dissolution velocity (7.6 fold). SmartCrystals® loaded or not into gels proved to be physically stable over a period of three months at 25°C. Interestingly, in vitro DPPH assay confirmed the preservation of quercetin antioxidative properties after nanonization. In parallel, the nanocrystalline form did not display cellular toxicity, even at high concentration (50μg/ml), as assayed on an epithelial cell line (VERO cells). In addition, the nanocrystalline form confirmed a protective activity for VERO cells against hydrogen peroxide induced toxicity in vitro. This new formulation presents a promising approach to deliver quercetin efficiently to skin in well-tolerated formulations.

Quercetin Attenuates Chronic Ethanol-Induced Hepatic Mitochondrial Damage through Enhanced Mitophagy

Emerging evidence suggested mitophagy activation mitigates ethanol-induced liver injury. However, the effect of ethanol on mitophagy is inconsistent. Importantly, the understanding of mitophagy status after chronic ethanol consumption is limited. This study evaluated the effect of quercetin, a naturally-occurring flavonoid, on chronic ethanol-induced mitochondrial damage focused on mitophagy. An ethanol regime to mice for 15 weeks (accounting for 30% of total calories) led to significant mitochondrial damage as evidenced by changes of the mitochondrial ultrastructure, loss of mitochondrial membrane potential and remodeling of membrane lipid composition, which was greatly attenuated by quercetin (100 mg/kg.bw). Moreover, quercetin blocked chronic ethanol-induced mitophagy suppression as denoted by mitophagosomes-lysosome fusion and mitophagy-related regulator elements, including LC3II, Parkin, p62 and voltage-dependent anion channel 1 (VDAC1), paralleling with increased FoxO3a nuclear translocation. AMP-activated protein kinase (AMPK) and extracellular signal regulated kinase 2 (ERK2), instead of AKT and Sirtuin 1, were involved in quercetin-mediated mitophagy activation. Quercetin alleviated ethanol-elicited mitochondrial damage through enhancing mitophagy, highlighting a promising preventive strategy for alcoholic liver disease.

In vitro scleral lutein distribution by cyclodextrin containing nanoemulsions

Lutein is a macular pigment that contributes to maintaining eye health. The development of lutein-laden nanocarriers for ocular delivery would have the advantages of user friendliness and cost-effectiveness. Nano-scaled vehicles such as cyclodextrin (CD) and nanoemulsion could overcome the barriers caused by the scleral structure. This study focused on the development of hybrid nanocarriers containing nanoemulsion and CD for scleral lutein accumulation. In the presence of the nanoemulsion, CD forms such as βCD and hydroxyethyl (HE) βCD increased the partition of lutein into the porcine sclera. A combination of nanoemulsion and 2% HEβCD enhanced lutein accumulation to 119±6 µg g(-1) h(-1), which was 9.2-fold higher than that with lutein suspension alone. We explored the dose effect of CD in nanoemulsion on scleral lutein and found that the scleral accumulation of lutein was enhanced by increasing the CD content. The novel nanoemulsion had 95% drug-loading efficiency and low cytotoxicity in retinal cells. The CD-modified nanoemulsion not only improved the stability and entrapment efficacy of lutein in the aqueous system but also enhanced scleral lutein accumulation. An increase in the partition coefficient of lutein in porcine sclera when using the CD-modified nanoemulsion was also confirmed.

Modulation of Pharmacokinetic and Cytotoxicity Profile of Imatinib Base by Employing Optimized Nanostructured Lipid Carriers

PURPOSE

To prepare, optimize and characterize imatinib-loaded nanostructured lipid carriers (IMT-NLC), and evaluate their pharmacokinetic and cytotoxicity characteristics.

METHODS

IMT-NLC was prepared by hot homogenization method, and optimized by an approach involving Plackett-Burman design (PBD) and central composite design (CCD). An in vivo pharmacokinetic study was conducted in rats after both oral and intravenous administration. The in vitro cytotoxicity was evaluated by MTT assay on NCI-H727 cell-lines.

RESULTS

PBD screening, followed by optimization by CCD and desirability function, yielded an optimized condition of 0.054, 6% w/w, 2.5% w/w and 1.25% w/v for organic-to-aqueous phase ratio (O/A), drug-to-lipid ratio (D/L), amount of lecithin (Lec) and amount of Tween® 20 (Tw20) respectively. The optimized IMT-NLC exhibited a particle size (Sz) of 148.80 ± 1.37 nm, polydispersity index (PDI) 0.191 ± 0.017 of and ζ-potential of -23.0 ± 1.5 mV, with a drug loading (DL) of 5.48 ± 0.01% and encapsulation efficiency (EE) of 97.93 ± 0.03%. IMT-NLC displayed sustained IMT release in vitro, significantly enhanced in vivo bioavailability of IMT after intravenous and oral administration, and greater in vitro cytotoxicity on NCI-H727 cells, compared with free IMT.

CONCLUSION

A combined DoE approach enabled accurate optimization and successful preparation of IMT-NLC with enhanced in vivo pharmacokinetic and in vitro cytotoxicity characteristics.

Quercetin in anti-diabetic research and strategies for improved quercetin bioavailability using polymer-based carriers – a review

With numerous pharmacological and biological functions bio-flavonoids gain appreciable attention in diabetes and other therapeutic research.

Nano graphene oxide: a novel carrier for oral delivery of flavonoids

The interesting physical and chemical properties of graphene oxide (GO) have led to much excitement among biomedical scientists in recent years. It is known that many potent, often aromatic medicines are water insoluble, and this has hindered their administration to treat diseases. Nano GO was synthesized and investigated for its biological application as a carrier for quercetin, a focused bioactive flavonoid widely used as a health supplement and a drug candidate. Different techniques were used to fully evaluate the synthesis, cytotoxicity, and quercetin loading capacity of nano GO. AFM and TEM results confirmed the preparation of planar nanoparticles without aggregation which was verified by reported size results (30 nm) obtained with a particle size analyzer. FTIR and DSC results proved the drug-carrier interaction. In vitro cytotoxicity assays showed that nano GO had no cytotoxicity on A549 cells in different amounts after incubation for 72 h, confirming its suitability as a drug carrier. Our results showed that nano GO can be proposed as a new carrier due to its small size, large specific surface area, low cost, and useful non-covalent interactions with aromatic low-soluble flavonoids such as quercetin. Moreover, it may find widespread applications in biomedicine.

Nanotechnology-based drug delivery systems for treatment of oral cancer: a review

Oral cancer (oral cavity and oropharynx) is a common and aggressive cancer that invades local tissue, can cause metastasis, and has a high mortality rate. Conventional treatment strategies, such as surgery and chemoradiotherapy, have improved over the past few decades; however, they remain far from optimal. Currently, cancer research is focused on improving cancer diagnosis and treatment methods (oral cavity and oropharynx) nanotechnology, which involves the design, characterization, production, and application of nanoscale drug delivery systems. In medicine, nanotechnologies, such as polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, gold nanoparticles, hydrogels, cyclodextrin complexes, and liquid crystals, are promising tools for diagnostic probes and therapeutic devices. The objective of this study is to present a systematic review of nanotechnology-based drug delivery systems for oral cancers.