Quercetin Suspension Research Articles

Simple preparation and greatly improved oral bioavailability: The supersaturated drug delivery system of quercetin based on PVP K30.

Quercetin, as a representative flavonoid, is widely present in daily diet and has been developed as a dietary supplement due to its beneficial physiological activities. However, the application of quercetin is limited due to its poor water solubility and extensive metabolism. So far, the nano-drug delivery systems designed to improve its bioavailability generally have the shortcomings of low drug loading content and difficulty in industrial production. In order to tackle these problems, quercetin supersaturated drug delivery system (QSDDS) was successfully prepared using solvent method, for which PVP K30 was employed as a crystallization and precipitation inhibitor to maintain the supersaturated state of quercetin in aqueous system. The obtained QSDDS, with a relative high drug loading content of 13%, could quickly disperse in water and form colloidal system with the mean particle size of about 200nm, meanwhile induce the generation of supersaturated quercetin solution more than 12h. In vivo pharmacokinetic study proved that QSDDS achieved a high absolute bioavailability of 36.05%, 10 times as that of physical quercetin suspension, which was dose-dependent with higher bioavailability at higher dose. Considering the simple preparation method, QSDDS provided a feasible strategy and a simple way to improve oral absorption of insoluble flavonoids.

Therapeutic Potential of Quercetin-Loaded Nanoemulsion against Experimental Visceral Leishmaniasis: In Vitro/Ex Vivo Studies and Mechanistic Insights.

Visceral leishmaniasis (VL) is one of the most fatal and neglected tropical diseases caused by Leishmania donovani (L. donovani). The applications of currently available chemotherapy (amphotericin B, miltefosine, and others) in VL treatment have been limited due to their poor bioavailability, unfavorable toxicity profile, and prolonged parenteral dosing. Quercetin (QT), a potent natural antioxidant, is a prominent target when conducting investigations on alternative therapies against L. donovani infections. However, the therapeutic applications of QT have been restricted due to its low solubility and bioavailability. In the present study, we developed and evaluated the antileishmanial activity (ALA) of quercetin-loaded nanoemulsion (QTNE) against L. donovani clinical strains. In vitro anti-promastigote assay results demonstrated that QTNE (IC50 6.6 μM, 48 h) significantly inhibited the growth of parasites more efficiently than the pure QT suspension in a dose- and time-dependent manner. Results of the anti-amastigote assay revealed that the infected macrophages (%) of QTNE were significantly more than those of the pure QT suspension at all concentrations (6.6, 26.4, and 52.8 μM; p < 0.05, p < 0.01 compared to the control). Moreover, the results of in vitro and ex vivo studies assisted in determining the mechanistic insights associated with the ALA of QTNE. The overall findings suggested that QTNE exhibited potential ALA by enhancing the intracellular ROS and nitric oxide levels, inducing distortion of membrane integrity and phosphatidylserine release (AV/PI), rupturing the parasite DNA (late apoptosis/necrosis process), and upregulating the immunomodulatory effects (IFN-γ and IL-10 levels). Additionally, QTNE showed superior biocompatibility against all of the treated healthy cells (PBMCs, PECs, and BMCs) as compared to the control. In conclusion, QTNE acts as a potential antileishmanial agent targeting both promastigote and intracellular amastigote forms of L. donovani, which thus opens a new avenue for the use of QTNE in VL therapy.

Enhancing the oral bioavailability of asenapine maleate with bio-enhancer: An in-silico assisted in-vivo pharmacokinetic study

The present work is aimed to address the oral bioavailability issue of asenapine maleate with the help of bio-enhancers. Molecular modeling platform by Maestro, Schrödinger was used to screen a list of bio-enhancer molecules. The bio-enhancer with the highest docking score and the best intermolecular interactions was selected for in-vivo pharmacokinetics studies. Of all the bio-enhancer molecules, quercetin showed the highest docking score (−10.6 on CYP1A2 and -9.34 on CYP3A4), induced fit docking score (−989.65 on CYP1A2 and -906.76 on CYP3A4) and greater association with proteins during molecular dynamics run. Animals were divided into five groups and orally administered with asenapine maleate and quercetin suspension at different dose and interval. The plasma was analyzed in high performance liquid chromatography, and various pharmacokinetic parameters were determined using Phoenix WinNonlin version 8.1. The presence of quercetin was found to significantly increase various pharmacokinetic parameters of asenapine maleate, and the groups administered with 25 mg/kg of quercetin showed better pharmacokinetic profile. A 2.5 folds increase in Cmax and 2.17 folds increase in AUC was observed in groups administered with quercetin. The increase in pharmacokinetic parameters could be attributed to the ability of the bio-enhancer to bind to the enzymes responsible for the metabolism of the drug, thereby prolonging the stay of drug in the body.

A Nano-Pharmaceutical Formula of Quercetin Protects from Cardiovascular Complications Associated with Metabolic Syndrome.

Metabolic syndrome (MetS) is closely associated with the development of cardiovascular diseases. We recently developed a nano-preparation of the flavonoid quercetin (QU) in a self-nanoemulsifying drug delivery system (SNEDDS). The latter comprised a mixture composed of pumpkin seed oil, D-α-Tocopherol polyethylene glycol 1,000 succinate and polyethylene glycol. The QU SNEDDS preparations exhibited a considerably higher bioavailability compared with the standard quercetin suspension. Here, we investigated whether the quercetin loaded SNEDDS could offer better protection compared with the standard formulation against cardiovascular complications of MetS in rats. MetS was induced by high fructose, high salt and high fat diet for 12 weeks while the nano-preparation or the standard suspension of quercetin was orally administered for the last 6 weeks. Compared to little effect for the standard quercetin suspension (MQ), the treatment of MetS rats with the quercetin loaded SNEDDS (MNQ) virtually abolished the depressant effect of MetS on contractility index (control, 114 ± 4; MetS, 92 ± 3; MQ, 100 ± 2; MNQ, 114 ± 6 1/s) and rate of rise in left ventricular pressure (dP/dtmax) (control, 8,171 ± 274; MetS, 6,664 ± 135; MQ, 6,776 ± 108; MNQ, 7,498 ± 303 mmHg/s). Likewise, the prolongation by MetS of electrocardiographic markers of arrhythmogenesis (QTc, JT, and Tpeak-to-Tend intervals) and concomitant rises in dicrotic notch pressure were preferentially reversed by quercetin nano-preparation. On the other hand, the rises in the isovolumic relaxation constant (Tau, denotes diastolic dysfunction), blood pressure, pulse pressure, and difference between systolic and dicrotic pressure (SDP difference) were equally improved by the two preparations of quercetin. Additionally, no differences were noted in the ability of the two quercetin preparations in abrogating the elevated oxidative (MDA) and inflammatory (TNFα) markers in cardiac tissues of MetS rats. Histopathological, microscopical signs of necrosis, inflammatory cell infiltration, and vascular congestion in MetS hearts were more markedly inhibited by the nano-preparation, compared with the standard preparation of quercetin. In conclusion, the quercetin loaded SNEDDS is evidently more advantageous than the standard preparation of the drug in alleviating functional and histopathological manifestations of cardiac damage incited by MetS.

Effect of quercetin on bone metabolism and serum osteocalcin in osteoporotic rats

Purpose: To determine the effect of quercetin on bone metabolism and serum osteocalcin in osteoporotic rats.&#x0D; Methods: Sixty specific pathogen-free rats were randomly divided into control group, model group; high, medium and low dose quercetin groups, and diethylstilbestrol group, with 10 rats in each group. The high, middle and low dose quercetin groups were given quercetin suspension at doses of 200, 100, 50 mg/kg/day, respectively; the ethylene estradiol group was given ethylene estradiol (1.0 mg/kg/week), while control rats received ethylene estradiol at doses of 200, 100, 50 mg/kg/day. Rats in the model group were given saline. Samples were taken after 6 weeks of administration. The levels of serum bone-derived alkaline phosphatase (BALP), estradiol (E2) and serum osteocalcin (BGP) in femur tissue were measured using ELISA kits. Bone mineral density (BMD) was determined using BMD tester.&#x0D; Results: Relative to normal rats, BALP and BGP levels in the model rats were markedly increased, while E2 was significantly lower (p &lt; 0.5). Quercetin treatment led to significant increases in BALP and E2 levels in the middle and high dose groups, relative to the model group, while BGP levels in all quercetin treatment groups decreased significantly, when compared to model rats (p &lt; 0.05). There were higher BMD values in quercetin and diethylstilbestrol groups than in model (p &lt; 0.05).&#x0D; Conclusion: Quercetin enhances bone formation and BMD, but decreases osteocalcin levels and maintains bone biomechanics in ovariectomized rats. Thus, it may find therapeutic application in maintaining bone health.&#x0D; Keywords: Quercetin, Osteoporosis, Bone metabolism, Osteocalcin

Preparation and in vitro and in vivo evaluation of quercetin-loaded mixed micelles for oral delivery.

Quercetin (QT) is a plant polyphenol with various pharmacological properties. However, the low water solubility limits its therapeutic efficacy. In the present study, QT-loaded sodium taurocholate-Pluronic P123 (QT-loaded ST/P123) mixed micelles were developed and characterized, and the effect of the formulation on improving the water solubility of QT was investigated. QT-loaded ST/P123 mixed micelles were prepared by thin film hydration-direct dissolution and optimized by uniform design. The optimal formulation possessed high drug loading (12.6%) and entrapment efficiency (95.9%) in small (16.20nm) spherically-shaped micelles. A low critical micelle concentration indicated that the micelles were stable, and they showed a sustained release pattern, as determined in vitro in simulated gastric fluid and intestinal fluid. Pharmacokinetic evaluation showed the Cmax and AUC0-24 were 1.8-fold and 1.6-fold higher than the QT suspension. The present results indicate that QT-loaded ST/P123 micelles are potential candidates to improve the solubility and oral bioavailability of QT.

Enhanced oral bioavailability of quercetin by a new non‐aqueous self‐double‐emulsifying drug delivery system

The present study investigated a new non‐aqueous self‐double‐emulsifying drug delivery system (SDEDDS) to enhance oral bioavailability of quercetin (QT), a drug with poor water solubility. The new formulation was prepared using a modified two‐step method and evaluated in vitro and in vivo. The optimized formulation consisted of oil‐in‐oil emulsions and hydrophilic surfactant that could spontaneously emulsify to oil‐in‐oil‐in‐water (O/O/W) double emulsions in the mixed aqueous gastrointestinal environment, with drugs mainly encapsulated in the inner oil phase of the double emulsions. Furthermore, the non‐aqueous QT‐SDEDDS exhibited sustained release of quercetin under conditions mimicking gastrointestinal tract, and gave significantly higher AUC and Cmax than did quercetin control suspension (p &lt; 0.05). In particular, the AUC of the non‐aqueous QT‐SEDDS was about 5.22‐fold higher than that of drug control suspension, with an absolute bioavailability of 26.67%. The obtained results demonstrated that SDEDDS was successfully developed and could be a promising technique for improving the oral bioavailability of quercetin with low solubility.Practical applications:Conventional SDEDDS is mainly designed to encapsulate, protect, and release hydrophilic bioactive components. Hence, the new non‐aqueous SDEDDS could as a drug delivery system to encapsulate hydrophobic drug with low oral bioavailability. Pharmacokinetic studies have displayed increased relative bioavailability (more than fivefold) of QT‐SDEDDS compared to quercetin suspension in rats after oral administration, with an absolute bioavailability of 26.67%. The new formulation was prepared using a modified two‐step method, which is widespread and easy to handle. Furthermore, the used excipients are considered generally recognized as safe (GRAS) for addition to food and/or drug products. Regard to industrial production aspects, the non‐aqueous SDEDDS have the chance to be exploited as drug delivery system in commercial products. Hence, the non‐aqueous SDEDDS could be applicable delivery system for hydrophobic compounds with low oral bioavailability.(i) The new non‐aqueous QT‐SDEDDS could spontaneously emulsify to oil‐in‐oil‐in‐water (O/O/W) double emulsions upon mild agitation by dilution in aqueous media; and (ii) after oral administration in rats, the non‐aqueous SDEDDS displayed an absolute bioavailability of 26.67%, which was 5.22 times higher than that of quercetin control suspension.

LC-ESI-MS/MS analysis of quercetin in rat plasma after oral administration of biodegradable nanoparticles.

A simple, rapid and sensitive LC-MS/MS method was developed and validated for the determination of free quercetin in rat plasma, using fisetin as internal standard. The detection was performed by negative ion electrospray ionization under selected reaction monitoring. Chromatographic separation (isocratic elution) was carried out using acetonitrile-10 m m ammonium formate (80:20, v/v) with 0.1% v/v formic acid. The lower limit of quantification (4.928 ng/mL) provided high sensitivity for the detection of quercetin in rat plasma. The linearity range was from 5 to 2000 ng/mL. Intra- and inter-day variability (RSD) of quercetin extraction from rat plasma was <4.19 and 1.37% with accuracies of 98.77 and 99.67%. The method developed was successfully applied for estimating free quercetin in rat plasma, after oral administration of quercetin-loaded biodegradable nanoparticles (QLN) and quercetin suspension. QLN (C(max), 1277.34 ± 216.67 ng/mL; AUC, 17,458.25 ± 3152.95 ng hr/mL) showed a 5.38-fold increase in relative bioavailability as compared with quercetin suspension (C(max), 369.2 ± 108.07 ng/mL; AUC, 3276.92 ± 396.67 ng hr/mL).

Design and Optimization of Self-Nanoemulsifying Delivery System to Enhance Quercetin Hepatoprotective Activity in Paracetamol-Induced Hepatotoxicity

The present study aimed to develop optimized quercetin (QT)-loaded self-nanoemulsifying drug delivery system (SNEDDS) that offers protective effect against liver damage. Solubility study of QT in different oils, surfactants, and cosurfactants was performed. Ternary phase mixtures of the selected components were constructed to select a suitable range for each component. Experimental mixture design was utilized to optimize SNEDDSs that possess smaller globule size with enhanced emulsification and dissolution rates. QT SNEDDS was compared with QT suspension control and silymarin. In vivo evaluation and histopatholgical study of the selected QT SNEDDSs were achieved after administration of paracetamol over dosage to albino rats. Two optimized formulations were selected; one based on Sefsol and the other based on linoleic acid as an oily phase, Tween(®) 80 and polyethylene glycol 400 as surfactant and cosurfactant, respectively. Both Sefsol and linoleic-acid-optimized SNEDDS formulation showed no symptoms associated with toxicity and offered protective effect against paracetamol-induced hepatotoxicity by scavenging free radicals, attenuating lipid peroxidation, and enhancing the activity of antioxidants. The histopatholgical observations revealed that the inflammatory infiltrations induced by paracetamol were significantly ameliorated.

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 126.6nm, a zeta potential of 40.5mV 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.

Novel self-emulsifying formulation of quercetin for improved in vivo antioxidant potential: Implications for drug-induced cardiotoxicity and nephrotoxicity

Quercetin (QT) was formulated into a novel self-emulsifying drug delivery system (SEDDS) to improve its oral bioavailability and antioxidant potential compared to free drug. Capmul MCM was selected as the oily phase on the basis of optimum solubility of QT in oil. Tween 20 and ethanol were selected as surfactant and cosurfactant from a large pool of excipients, depending upon their spontaneous self-emulsifying ability with the selected oily phase. Pseudoternary-phase diagrams were constructed to identify the efficient self-emulsification regions in various dilution media, viz., water, pH 1.2, and pH 6.8. The ratio of 40:40:20 w/w, Capmul MCM:QT (19:1)/Tween 20/ethanol was optimized based on its ability to form a spontaneous submicrometer emulsion in simulated gastrointestinal fluids. DPPH scavenging assay showed comparable antioxidant activity of QT-SEDDS to free QT. QT-SEDDS was robust in terms of stability against short-term excursion of freeze/thaw cycles and accelerated stability for 6 months as per International Conference on Harmonisation guidelines. A fluorescent dye-loaded SEDDS formulation showed rapid internalization within 1h of incubation with Caco-2 cells as evident by confocal laser scanning microscopy. QT-SEDDS showed a significant increase in cellular uptake by 23.75-fold in comparison with free QT cultured with Caco-2 cells. The SEDDS demonstrated ~5-fold enhancement in oral bioavailability compared to free QT suspension. The in vitro–in vivo relation between in vitro Caco-2 cell uptake and in vivo pharmacokinetics of QT-SEDDS showed a correlation coefficient of ~0.9961, as evident from a Levy plot. Finally, QT-SEDDS showed a significantly higher in vivo antioxidant potential compared to free QT when evaluated as a function of ability to combat doxorubicin- and cyclosporin A-induced cardiotoxicity and nephrotoxicity, respectively.

Cocoa intake attenuates oxidative stress associated with rat adjuvant arthritis

Cocoa contains flavonoids with antioxidant properties. The aim of this study was to ascertain the effect of cocoa intake on oxidative stress associated with a model of chronic inflammation such as adjuvant arthritis. Female Wistar rats were fed with a 5% or 10% cocoa-enriched diet or were given p.o. a quercetin suspension every other day for 10days. Arthritis was induced by a heat-killed Mycobacterium butyricum suspension. Reactive oxygen species (ROS) produced by macrophages, and splenic superoxide dismutase (total, cytoplasmic and mitochondrial) and catalase activities were determined. Clinically, joint swelling in arthritic rats was not reduced by antioxidants; however, the 5% cocoa diet and quercetin administration reduced ROS production. Moreover, the 5% cocoa diet normalized the activities of superoxide dismutase and catalase. In conclusion, a cocoa diet reduces the oxidative stress associated with a chronic inflammatory pathology, although it was not enough to attenuate joint swelling.

Development of quercetin nanoformulation and in vivo evaluation using streptozotocin induced diabetic rat model.

Quercetin-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Qu-NP) were prepared by emulsion-diffusion-evaporation method and characterized as 179.9 ± 11.2nm in size with 0.128 as polydispersity index, more than 86% drug entrapment efficiency, and zeta potential was -6.06 ± 1.51mV. D-Trehalose (5% w/v) was found to be a suitable cryoprotectant for lyophilization of Qu-NP, and antioxidant assays indicated that Qu-NP were able to retain the antioxidant property similar to that of free drug at equivalent concentration after formulation development. In vitro release study of Qu-NP showed a controlled release pattern of quercetin. An enhanced oral bioavailability (523% relative increase) was observed in pharmacokinetic study with a 6-day sustained release from Qu-NP as compared to quercetin suspension, which indicated the reduced dosing frequency. Efficacy in diabetic rats suggested that same dose of Qu-NP on every fifth day was sufficient to bring effect similar to daily dose of oral quercetin suspension, and the same effect was also observed for catalase and superoxide dismutase levels in pancreas and kidneys. Thus, the system offers an efficacious oral therapy with reduced dose and dosing frequency for treatment of diabetes and is hence patient compliant.

Anti-inflammatory effect of quercetin-loaded microemulsion in the airways allergic inflammatory model in mice

Quercetin is a plant-derived flavonoid widely known by its anti-oxidant and anti-inflammatory properties, but its oral bioavailability is very poor and this becomes difficult to assess its therapeutic potential. Here we have compared the anti-inflammatory effect of quercetin-loaded microemulsion (QU-ME) and quercetin suspension (QU-SP) in an experimental model of airways allergic inflammation. Mice received daily oral doses of QU-ME (3 or 10 mg/kg; in an oil-in-water microemulsion content 0.02:0.2:1 of lecithin:castor oil:Solutol HS15 ®), QU-SP [10 mg/kg, in carboxymethylcellulose (CMC) 0.5% in water] or vehicle from the 18th to the 22nd day after the first immunization with ovalbumin (OVA). Dexamethasone was used as positive control drug. Every parameter was evaluated in the 22nd day (24 h after the second OVA-challenge). We have also tried to assess by HPLC–MS a quercetin metabolite in the blood of rats treated with QU-SP or QU-ME. QU-ME was better orally absorbed when compared with QU-SP. Furthermore, oral administration of QU-SP failed to interfere with leukocyte recruitment, while QU-ME inhibited in a dose-dependent way, the eosinophil recruitment to the bronchoalveolar lavage fluid (BALF). QU-ME also significantly reduced both IL-5 and IL-4 levels, but failed to interfere with CCL11, IFN-γ and LTB 4 levels. In addition, QU-ME oral treatment inhibited the nuclear transcription factor kappa B (NF-κB) activation, P-selectin expression and the mucus production in the lung. The present results show that QU-ME exhibits pronounced anti-inflammatory properties in a murine model of airways allergic inflammation and suggest that it might present therapeutic potential for the airways inflammatory diseases management.

Nanoencapsulation of quercetin enhances its dietary efficacy in combating arsenic-induced oxidative damage in liver and brain of rats

Aims This study was performed to evaluate the therapeutic efficacy of nanocapsulated flavonoidal quercetin (QC) in combating arsenic-induced reactive oxygen species (ROS)-mediated oxidative damage in hepatocytes and brain cells in a rat model. Main methods Hepatic and neuronal cell damage in rats was made by a single injection (sc) of sodium arsenite (NaAsO 2, 13 mg/kg b. wt. in 0.5 ml of physiological saline). A single dose of 500 µl of quercetin suspension (QC) (QC 8.98 µmol/kg) or 500 µl of nanocapsulated QC (NPQC) (QC 8.98 µmol/kg) was given orally to rats at 90 min prior to the arsenite injection. Key findings Inorganic arsenic depositions (182 ± 15.6 and 110 ± 12.8 ng/g protein) were found in hepatic and neuronal mitochondrial membranes. Antioxidant levels in hepatic and neuronal cells were reduced significantly by arsenic. NPQC prevented the arsenite-induced reduction in antioxidant levels in the liver and brain. Arsenic induced a substantial decrease in liver and brain cell membrane microviscosities, and NPQC treatment resulted in a unique protection against the loss. A significant correlation between mitochondrial arsenic and its conjugated diene level was observed both in liver and brain cells for all experimental rats. Significance Arsenic-specific antidotes are used against arsenic-induced toxicity. However, the target site is poorly recognized and therefore achieving an active concentration of drug molecules can be a challenge. Thus, our objective was to formulate NPQC and to investigate its therapeutic potential in an oral route against arsenite-induced hepatic and neuronal cell damage in a rat model.

Enhancement of gastrointestinal absorption of quercetin by solid lipid nanoparticles

The aim of the present study is to design and characterize quercetin-loaded solid lipid nanoparticles (QT-SLNs), clarify the absorption mechanism of QT-SLNs and to evaluate the potential of using solid lipid nanoparticles (SLNs) as an oral delivery carrier for poorly water soluble drugs. QT-SLNs were prepared by an emulsification and low-temperature solidification method. The QT-SLNs presented as spherically shaped under transmission electron microscopy, with an average diameter of 155.3 nm. The average drug entrapment efficiency, drug loading and zeta potential were 91.1%, 13.2% and − 32.2 mV, respectively. Drug release from QT-SLNs was fitted to a double phase kinetics model and the equation was as follows: 100 − Q = 98.87e − 0.1042t + 42.45e − 0.0258t . The absorption of QT-SLNs in the gastrointestinal (GI) tract was studied using an in situ perfusion method in rats. It was found that the absorption percent in the stomach for 2 h was only 6.20% , the absorption process of intestine was first-process with passive diffusion mechanism, and the main absorptive segments were ileum and colon. A pharmacokinetic study was conducted in rats after oral administration of quercetin at 50 mg/kg in the form of either QT-SLNs or suspension. The plasma concentration-time curves were both fitted to a one-compartment model. The relative bioavailability of QT-SLNs to quercetin suspension was 571.4%. The T max and MRT for quercetin in plasma were both delayed. Our studies provide evidence that SLNs are valuable as an oral delivery carrier to enhance the absorption of a poorly water soluble drug, quercetin.

Influence of excipients and technological process on anti-inflammatory activity of quercetin and Achyrocline satureioides (Lam.) D.C. extracts by oral route

The flavonoids quercetin, 3-O-methylquercetin and luteolin play an important role in the anti-inflammatory activity of Achyrocline satureioides ethanol extracts when administered intraperitoneally. The present work describes the oral anti-inflammatory effect of quercetin and A. satureioides extracts and the role played by the solvent concentration, adjuvant and drying processes of freeze-drying (FD) or spray-drying (SD) on the effect. The best anti-edema effect was observed with 250 mg/kg body wt of the freeze-dried powder (FDP), prepared with 40% (v/v) ethanol (FDP40). In contrast, 250 mg/kg body wt of FDP80, prepared with ethanol 80% (ES80), did not significantly inhibit the carrageenan-induced rat paw edema. However, when ES80 was freeze-dried in the presence of polysorbate 80 (FDP80-P80) or spray-dried in the presence of colloidal silicon dioxide (CSD) and P80 (SDP80), both dried extracts became more active. Quercetin suspension in saline did not inhibit paw edema, but the mixture of quercetin with polysorbate 80 was effective in edema inhibition by the oral route. Aqueous extract (ESAQ), freeze-dried (FDPAQ, FDPAQ-P80) or spray-dried (SDPAQ) did not exhibit the edema-inhibition effect. Taken together, the results point to the following order of efficacy (at 4 h, for example): FDP40 > indomethacin > SDP40 > SDP80 = FDP80-80 > Quercetin-P80. Additionally, the FDP40, SDP40 (prepared from 40% v/v ethanol added of CSD) and SDP80 reduced the total leukocyte and polymorphonuclear cell migration in the pleural cavity.