Oral Administration In Rats Research Articles

Bioavailability of phenolic compounds and antioxidant effects of wine pomace seasoning after oral administration in rats

The bioavailability of phenolics contained in a powdered red wine pomace seasoning (RWPS) and its beneficial effects after acute and short-term supplementation were investigated. First, a single oral-dose of RWPS (300 mg/kg body weight) was administered to healthy Wistar rats (n = 6) and several phenolic acids were determined post-RWPS intake in plasma (0, 2 and 4 h) and urine (−3 to 0, 0–3 and 3–6 h). Higher prevention of lipid peroxidation (plasma and urinary F2-isoprostanes) and improved nitric oxide bioavailability were observed in samples collected at 4 h and between 3 and 6 h (p < 0.05), suggesting an important antioxidant role of the metabolites generated by the action of colonic microbiota. In contrast, following 4 weeks of daily RWPS consumption, no significant differences were detected between supplemented and control groups for any of the biomarkers assessed, which indicates that acute beneficial effects of RWPS intake might be only transient under normal physiological conditions for this rat model.

Oral Bioavailability and Mass Balance Studies of a Novel Anti-arrhythmic Agent Sulcardine Sulfate in Sprague-Dawley Rats and Beagle Dogs.

Sulcardine sulfate is a newly developed candidate drug used to control arrhythmias. The aim of this research was to investigate the pharmacokinetics, bioavailability and excretion characteristics of sulcardine in animals. Sprague-Dawley rats were orally and intravenously given sulcardine at 20 and 40mg/kg. Beagle dogs were also orally and intravenously dosed at 10mg/kg. Both [3H]-labeled sulcardine and unlabeled sulcardine were given to rats. Feces, urine and bile were collected at 0-72h for mass balance study. The contents of unlabeled sulcardine and radioactivity in samples were determined by a validated LC-MS/MS method and by liquid scintillation counting, separately. Sulcardine was rapidly eliminated in rats after dosing. The oral bioavailability was 34-35% in rats, while a higher exposure was observed in dogs (bioavailability=62.7%). More than 90% of dosed sulcardine was recovered, and approximately 20-40% of the dose excreted into urine as the original form, and the remaining was found in feces and bile, most of which (about 40%) was transformed into metabolites. No difference was observed between sexes. Metabolism may occur to a large extent after oral administration in rats but to a smaller extent in dogs. Sulcardine was extensively absorbedin both rats and dogs after oral administration. The mass balance data indicated that sulcardine was widely metabolized in rats after oral administration.

Hybridization of polyvinylpyrrolidone to a binary composite of curcumin/α-glucosyl stevia improves both oral absorption and photochemical stability of curcumin

The tri-component system curcumin/α-glucosyl stevia (Stevia-G)/polyvinylpyrrolidone (PVP) was developed to improve the oral bioavailability and physicochemical properties of curcumin (CUR). The tri-component CUR formulation with Stevia-G and PVP was prepared with freeze-drying. The tri-component CUR system exhibited 13,000-fold higher solubility of CUR than the equilibrium solubility of CUR for 24h, indicating a stable tri-composite structure involving CUR. CUR could be converted into an amorphous form in the presence of Stevia-G and PVP by freeze-drying. The photo-degradation of CUR in the tri-component system was negligible even under an amorphous state of CUR. After oral administration in rats, the oral absorption of the tri-component CUR formulation (20mgCUR/kg) was 6.7-fold higher than that of crystalline CUR. The tri-component CUR formulation would therefore be a promising option to improve physicochemical properties and oral absorption of CUR.

Pharmacokinetics of 16-dehydropregnenolone hydroxypropyl-β-cyclodextrin inclusion complex following peroral administration

16-Dehydropregnenolone (16-DHP) is an active compound with an unsatisfied in vivo behavior and poor water-solubility, which limits its clinical application. To improve its in vivo behavior and water-solubility, a Hydroxypropyl-beta-Cyclodextrin (HP-β-CD) inclusion complex of 16-DHP was prepared in this paper. Pharmacokinetic studies after oral administration of 16-DHP–HP-β-CD at doses of 37.5, 75, 150 mg/kg were carried out to investigate its dose proportionality in rats. The relative bioavailability was researched by comparing the area under the plasma concentration–time curve of 16-DHP–HP-β-CD and free 16-DHP after oral administration in rats at the dose of 75 mg/kg. At the same time, tissue distribution of 16-DHP–HP-β-CD after oral administration at the dose of 240 mg/kg in mice was also investigated. Consequently, 16-DHP–HP-β-CD appeared to be a linear pharmacokinetic character after peroral administration to the rat at the doses tested. Compared to free 16-DHP, inclusion complex could significantly improve the relative bioavailability (467%). Tissue distribution studies indicated that 16-DHP–HP-β-CD tended to distribute into stomach, intestine, lung, brain and liver.

PH-dependent release of platycodin mitigates its gastrointestinal mucosa irritation after oral administration in rats.

The present study aimed to evaluate the gastrointestinal mucosa irritation of three platycodin formulations. Platycodin-loaded core pellets were prepared via extrusion-spheronization method and coated with Eudragit(®) L100-55 (L100) or Eudragit(®) S100 (S100) for pH-dependent release. The release of platycodin D from coated pellets exhibited pH dependent release profiles. The pharmacokinetic study in rats showed that Tmax of the coated pellets were prolonged as compared to that of un-coated pellets. The S100-coated pellets possess a lower Cmax and decreased AUC0-24h as compared to the L100-coated and uncoated pellets. Hematoxylin-eosin staining and nuclear factor Kappa B (NF-κB) measurement were carried out to observe the gastrointestinal mucosa irritations. The results revealed that the irritations of platycodin on the upper gastrointestinal mucosa are dose-dependent. However, no obvious irritation effect on the gastrointestinal tissues of rats was detected after oral administration of the coated pellets. In addition, the amount of NF-κB in the stomach of rats treated with the uncoated pellets was about fivefold higher as compared to that of the coated pellets. In summary, the L100-coated platycodin pellets exhibited higher oral bioavailability and less gastrointestinal mucosa irritations as compared to the other two formulations.

Effects of glycosides components and combinations of Buyang Huanwu decoction on vascular smooth muscle cells proliferation and related signaling pathway

This paper was aimed to explore the effects of glycosides, the effective component of Buyang Huanwu decoction, and its main active components such as astragaloside Ⅳ, amygdalin, peoniflorin and their combinations on vascular smooth muscle cells (VSMC) proliferation, clarify the major active materials of anti-VSMC proliferation and investigate the mechanisms via the signal transduction pathway. Plasma containing drug was prepared via oral administration in rats. VSMCs of rats aorta were cultured, and then VSMC proliferation was stimulated by using platelet derived growth factor (PDGF).The plasma containing drug was added to detect the activity of cell proliferation, cell cycle and related protein expressions of signaling pathway such as extracellular signal-regulated kinase (ERK), phos-phatidylinositol-3-kinase/protein kinase B (PI3K/Akt) and Janus kinase/signal transducer and activator of transcription (JAK/STAT). After being stimulated by PDGF, the proliferation activity of VSMC was strengthened (P<0.01), G₀/G₁ phase cells were decreased (P<0.01), S/M phase cells were increased (P<0.01), and PcNA, cyclin D1 protein expressions related to cell cycle were up-regulated (P<0.01). Glycosides, astragaloside Ⅳ, amygdalin, peoniflorin and their combinations could inhibit the cell proliferation (P<0.05 or P<0.01) in a dose-effect relationship and time-effect relationship. They could increase G₀/G₁ phase cells (P<0.01), decrease S/M phase cells (P<0.01), and down-regulate the protein expressions of PCNA, cyclin D1 (P<0.01); and the effects of the combinations were greater than those of single active component (P<0.05). After VSMC proliferation was induced by PDGF, p-ERK1/2 expression was increased (P<0.01), PI3K expression was down-regulated while p-PI3K expression was up-regulated (all P<0.01), and STAT3expression was reduced while p-STAT3 expression was increased (all P<0.01). Glycosides, astragaloside Ⅳ, amygdalin, peoniflorin and the combinations of these active components could reduce p-ERK1/2 expression (P<0.05), increase PI3K expression (P<0.01), decreasep-PI3K expression (P<0.05 or P<0.01), increase STAT3 expression (P<0.01), and decrease p-STAT3 expression (P<0.05 or P<0.01). These results suggested that PDGF could induce the cell cycle conversion of VSMC, leading to VSMC proliferation. The mechanism was related to the activation of ERK, PI3K/Akt and JAK/STAT signaling pathways. Glycosides and its main active components such as astragaloside Ⅳ, amygdalin, peoniflorin and their combinations can inhibit the cell cycle conversion of VSMC, with the effect against VSMC proliferation, and the mechanisms may be associated with the inhibition of PI3K/Akt, mitogen-activated protein kinase (MAPK) and JAK/STAT signaling pathways. astragaloside Ⅳ, amygdalin and peoniflorin were the major active materials of anti-VSMC proliferation, and their combination showed enhanced effect.

Analysis of the pharmacokinetics and metabolism of aloe-emodin following intravenous and oral administrations in rats.

Aloe-emodin, a natural polyphenolic anthraquinone, has shown various beneficial bioactivities in vitro. The aim of this study was to investigate the pharmacokinetics and metabolism of aloe-emodin. Aloe-emodin was intravenously and orally administered to rats. The concentrations of aloe-emodin and rhein, a metabolite of aloe-emodin, were determined by HPLC method prior to and after hydrolysis with β-glucuronidase and sulfatase/β-glucuronidase. The results showed that the systemic exposures of aloe-emodin and its metabolites were ranked as aloe-emodin glucuronides (G)>rhein sulfates (S)>aloe-emodin > rhein and rhein G when aloe-emodin was given intravenously. In contrast, when aloe-emodin was administered orally, the parent form of aloe-emodin was not absorbed per se, and the systemic exposures of its metabolites were ranked as aloe-emodin G>rhein G>rhein. In conclusion, the metabolites of aloe-emodin are more important than the parent form for the bioactivities in vivo. Copyright © 2016 John Wiley & Sons, Ltd.

Curcumin bioavailability from oil in water nano-emulsions: In vitro and in vivo study on the dimensional, compositional and interactional dependence

Although nanocarriers can enhance the bioavailability of free curcumin in the blood, a systematic study on the parameters that affect such enhancement is still missing. In this work we focused the attention on a nanocarrier represented by an oil in water nano-emulsion coated with a thiol modified chitosan and carried out a comprehensive study on the effects that parameters such as size, co-delivery of piperine and degree of chitosan modification can exert on curcumin bioavailability and quantified their impact. We obtained an unprecedented pharmacokinetic profile of curcumin with the best formulation, represented by a combination of a small nano-emulsion size (110nm), co-delivery of curcumin and piperine (weight ratio 100:1) and a high degree of chitosan thiolation (14–15%). Then, we assessed its anti-inflammatory properties after oral administration in rats at low doses (≤0.1 times the volume administered in the pharmacokinetic study). Furthermore, the proposed food grade nano-emulsions loaded with curcumin did not show any cytotoxic effect on normal fibroblasts, while they were able to promote death in colon cancer cells in agreement with the common knowledge of the selective action of curcumin.

Pyrene did not induce gene mutation in red blood cell Pig-a assay and PIGRET assay in rats

A new in vivo gene mutation assay has been developed based on the phosphatidylinositol glycan anchor biosynthesis, Class A gene (Pig-a in rodents) as an endogenous reporter. Although a large number of chemicals have been evaluated in the rat Pig-a assay in 28-day repeat dose regimens, there was limited reporting of rat Pig-a assay after a single dose. A collaborative study by the Mammalian Mutagenicity Study group, which is a subgroup of the Japanese Environmental Mutagen Society, was conducted to verify the usefulness of the rat Pig-a assay after a single dose as a short-term genotoxicity test. As a part of this collaborative study, the in vivo mutagenicity of a single dose of pyrene (Pyr) was investigated in the red blood cell (RBC Pig-a assay) and in reticulocytes (PIGRET) of rats. Eight-week old male rats were orally dosed with Pyr at 500, 1000, and 2000 mg/kg or ethylnitrosourea (ENU) at 10 and 40 mg/kg as a positive control. The animals in each group were examined for Pig-a mutant frequencies (MF) except for animals in the 2000mg/kg group because of mortality or severe toxicity. The Pig-a MF in RBCs and reticulocytes, as CD59 negative cells, were evaluated once a week for 4 weeks after the dosing. With a single exposure to ENU, the Pig-a MF in both RBCs and reticulocytes increased in a time- and dose-dependent manner. In contrast, no statistically significant effect was observed in rats dosed with Pyr at 500 and 1000 mg/kg. Therefore, Pyr was concluded to be negative in the RBC Pig-a assay and the PIGRET assay after a single oral administration in rats. The result was consistent with previously reported Pig-a assays with repeat dose regimens.

Duodenum-triggered delivery of pravastatin sodium: II. Design, appraisal and pharmacokinetic assessments of enteric surface-decorated nanocubosomal dispersions

Context: Pravastatin sodium (PVS) is a freely water-soluble HMG-CoA inhibitor that suffers from instability at gastric pH, extensive first pass metabolism, short elimination half-life (1–3 h) and low oral bioavailability (18%). Objective: To overpower these drawbacks and to maximize drug absorption at its main site of absorption at the duodenum, enteric surface-coated PVS-loaded nanocubosomal dispersions were presented. Materials and methods: Glyceryl monooleate (GMO)-based dispersions were developed by the fragmentation or the liquid precursor methods using Pluronic® F127 or Cremophor® EL as surfactants. As a challenging enteric-coating approach, the promising dispersions were surface-coated via lyophilization with Eudragit® L100-55; a duodenum-targeting polymer. The drug content, particle size, zeta potential, morphology and release studies of PVS-loaded dispersions were evaluated before and after surface-coating. Compared to an aqueous PVS solution, the pharmacokinetics of the best achieved system (E-F8) was evaluated (UPLC-MS/MS) in rats. Results: The enteric surface-coated nanocubosomal dispersions were more or less spherical in shape and showed high drug-loading, negative zeta potential values and fine-tuned biphasic drug-release patterns characterized by retarded (2 h) and sustained (10 h) phases in pH 1.2 and pH 6.8, respectively. E-F8 system showed significantly (p< 0.05) higher oral bioavailability, delayed Tmax and prolonged MRT0−∞ following oral administration in rats. Conclusions: The duodenum-triggering potential and the controlled-release characteristics of the best achieved system for smart PVS delivery were revealed.

Usefulness of liquid–crystal oral formulations to enhance the bioavailability and skin tissue targeting of p-amino benzoic acid as a model compound

Topical formulations are not always suitable to deliver active ingredients to large areas of skin. Thus, in this study, we aimed to develop an oral formulation for skin tissue targeting with a high bioavailability using liquid crystal (LC) dispersions comprising cubosomes of a mal-absorptive model compound, p-amino benzoic acid (PABA), which is an active element in cosmeceuticals, dietary supplements and skin disorder medicines. The bioavailability and skin concentration of PABA were investigated after oral administration in rats. The effect of the remaining amount of the LC formulation in the stomach on the pharmacokinetic profiles of orally administered PABA was evaluated. The skin permeation and concentration of PABA were also investigated using an in vitro permeation experiment. As a result, the bioavailability of PABA was significantly improved by administration of PABA–LC formulations compared with PABA solution alone, although the effect was greatly influenced by the type of LC-forming lipids. The in vitro skin permeation study showed that the PABA concentration in the skin when applied from the dermis side was higher than when applied from the epidermis side. These findings suggested that oral administration advantageously supports skin targeting, and oral LC formulations could be a promising material in cosmeceutical, dietary and clinical fields.

Improved Oral Bioavailability Using a Solid Self-Microemulsifying Drug Delivery System Containing a Multicomponent Mixture Extracted from Salvia miltiorrhiza.

The active ingredients of salvia (dried root of Salvia miltiorrhiza) include both lipophilic (e.g., tanshinone IIA, tanshinone I, cryptotanshinone and dihydrotanshinone I) and hydrophilic (e.g., danshensu and salvianolic acid B) constituents. The low oral bioavailability of these constituents may limit their efficacy. A solid self-microemulsifying drug delivery system (S-SMEDDS) was developed to load the various active constituents of salvia into a single drug delivery system and improve their oral bioavailability. A prototype SMEDDS was designed using solubility studies and phase diagram construction, and characterized by self-emulsification performance, stability, morphology, droplet size, polydispersity index and zeta potential. Furthermore, the S-SMEDDS was prepared by dispersing liquid SMEDDS containing liposoluble extract into a solution containing aqueous extract and hydrophilic polymer, and then freeze-drying. In vitro release of tanshinone IIA, salvianolic acid B, cryptotanshinone and danshensu from the S-SMEDDS was examined, showing approximately 60%–80% of each active component was released from the S-SMEDDS in vitro within 20 min. In vivo bioavailability of these four constituents indicated that the S-SMEDDS showed superior in vivo oral absorption to a drug suspension after oral administration in rats. It can be concluded that the novel S-SMEDDS developed in this study increased the dissolution rate and improved the oral bioavailability of both lipophilic and hydrophilic constituents of salvia. Thus, the S-SMEDDS can be regarded as a promising new method by which to deliver salvia extract, and potentially other multicomponent drugs, by the oral route.

BI 1002494, a Novel Potent and Selective Oral Spleen Tyrosine Kinase Inhibitor, Displays Differential Potency in Human Basophils and B Cells.

BI 1002494 [(R)-4-{(R)-1-[7-(3,4,5-trimethoxy-phenyl)-[1,6]napthyridin-5-yloxy]-ethyl}pyrrolidin-2-one] is a novel, potent, and selective spleen tyrosine kinase (SYK) inhibitor with sustained plasma exposure after oral administration in rats, which qualifies this molecule as a good in vitro and in vivo tool compound. BI 1002494 exhibits higher potency in inhibiting high-affinity IgE receptor-mediated mast cell and basophil degranulation (IC50 = 115 nM) compared with B-cell receptor-mediated activation of B cells (IC50 = 810 nM). This may be explained by lower kinase potency when the physiologic ligand B-cell linker was used, suggesting that SYK inhibitors may exhibit differential potency depending on the cell type and the respective signal transduction ligand. A 3-fold decrease in potency was observed in rat basophils (IC50 = 323 nM) compared with human basophils, but a similar species potency shift was not observed in B cells. The lower potency in rat basophils was confirmed in both ex vivo inhibition of bronchoconstriction in precision-cut rat lung slices and in reversal of anaphylaxis-driven airway resistance in rats. The different cellular potencies translated into different in vivo efficacy; full efficacy in a rat ovalbumin model (that contains an element of mast cell dependence) was achieved with a trough plasma concentration of 340 nM, whereas full efficacy in a rat collagen-induced arthritis model (that contains an element of B-cell dependence) was achieved with a trough plasma concentration of 1400 nM. Taken together, these data provide a platform from which different estimates of human efficacious exposures can be made according to the relevant cell type for the indication intended to be treated.

Preparation, characterization and pharmacokinetic studies of linalool-loaded nanostructured lipid carriers

Context Linalool (LL) is associated with numerous pharmacological activities. However, its poor solubility usually results in poor bioavailability, and further limited its applications.Objective To reduce volatilization and improve bioavailability of LL, linalool-loaded nanostructured lipid carriers (LL-NLCs) were prepared.Materials and methods LL-NLCs were prepared using high-pressure homogenization method and optimized via response surface methodology-central composite design, followed by characterization, including particle size (PS), zeta potential (ZP), transmission electron microscope (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and in vitro release study. Rats were administered 300 mg × kg − 1 LL with each preparation (LL-NLCs or LL) via oral gavage.Results LL-NLCs had a PS of 52.72 nm with polydispersity index of 0.172, and ZP of –16.0 mV. The encapsulation efficiency and drug loading gave 79.563 and 7.555%, respectively. The cumulative release of LL from free LL reached 51.414% at 180 min, while LL from LL-NLCs was 15.564%. All the pharmacokinetics parameters of LL-NLCs were better than those of LL, including Cmax (from 1915.45 to 2182.45 ng × mL − 1), AUC0–t (from 76003.40 to 298948.46 ng × min × mL − 1) and relative bioavailability (393.34%). The t1/2, MRT and tmax of LL-NLCs (110.50, 146.66 and 60 min) were also longer than that of LL (44.72, 45.66 and 40 min).Discussion and conclusion LL-NLCs were for the first time prepared and its oral administration in rats thoroughly investigated. LL-NLCs exhibited sustained release effect and increased absorption of LL. Therefore, these findings might provide a potential possibility for clinical application of LL.

Absorptive interactions of concurrent oral administration of (+)-catechin and puerarin in rats and the underlying mechanisms.

(+)-Catechin and puerarin are polyphenol and flavonoid, respectively, in green tea and foodstuffs. They exhibit potent antioxidant activity and are widely used for treating cardiocerebrovascular diseases. The aim of this work was to investigate the potential interactions between (+)-catechin and puerarin following concurrent oral administration in rats, and their absorption mechanisms in Caco-2 cell monolayers. Pharmacokinetic studies were conducted in male rats received (+)-catechin (140 mg/kg, po) and/or puerarin (200 mg/kg, po). The cell uptake and transport behavior in Caco-2 cell monolayers and the interactions of the two compounds were analyzed. When (+)-catechin and puerarin were administered concurrently, the AUC0-12 h and Cmax values of puerarin were 2.48-fold and 3.91-fold, respectively, as large as those of puerarin alone; the AUC0-12 h and Cmax values of (+)-catechin were decreased to 57.62% and 77.55%, respectively, compared with those of (+)-catechin alone. In Caco-2 cell monolayers, (+)-catechin (300 and 600 μmol/L) significantly increased the cell uptake and transport of puerarin, whereas puerarin (300 and 600 μmol/L) significantly decreased the cellular uptake and transport of (+)-catechin. Furthermore, both cyclosporine A (P-glycoprotein inhibitor) and MK-571 (MRP-2 inhibitor) significantly increased the cellular uptake and transport of (+)-catechin and puerarin. Concurrent oral administration of (+)-catechin and puerarin significantly increased the absolute oral bioavailability of puerarin, but decreasing that of (+)-catechin. The competitive efflux of (+)-catechin and puerarin by P-glycoprotein and MRP-2 might lead to this interaction during their absorption process in the small intestine.

Red blood cell Pig-a assay and PIGRET assay in rats with azathioprine

A new in vivo gene mutation assay has been developed based on the phosphatidylinositol glycan anchor biosynthesis, Class A gene (Pig-a in rodents) as an endogenous reporter. Using this Pig-a assay, the in vivo mutagenicity of a single dose of azathioprine (Aza) was investigated in red blood cells (RBC Pig-a assay) and reticulocytes (PIGRET) of rats. Eight-week old male rats were orally dosed once with Aza at 50, 100 and 200mg/kg or ethylnitrosourea (ENU) at 10 and 40mg/kg as a positive control. Because 4 out of 6 animals at 200mg/kg of Aza died 3days after the dosing, this dose group was excluded for analyses. The frequencies of Pig-a mutants in RBCs and reticulocytes (RET) were evaluated once a week for 4 weeks after the treatment. With a single exposure to ENU, the frequencies of Pig-a mutants in both RBCs and RETs increased in a time- and dose-dependent manner. In contrast, with Aza small effects that were not statistically significant were observed in rats at 21 and 14days in the RBC Pig-a and PIGRET assays respectively. Based on the present results, the mutagenic potential of Aza is negligible after single oral administration in rats.

Preparation and evaluation of valsartan by a novel semi-solid self-microemulsifying delivery system using Gelucire 44/14

The aim of the present study was to develop a novel semi-solid self-microemulsifying drug delivery system (SMEDDS) using Gelucire® 44/14 as oil with strong solid character to improve the oral bioavailability of poorly soluble drug valsartan. The solubility of valsartan in various excipients was determined, the pseudo-ternary phase diagram was constructed in order to screen the optimal excipients, and DSC analysis was performed to evaluate the melting point of SMEDDS. The optimal drug-loaded SMEDDS formulation was consisted of 30% Gelucire® 44/14 (oil), 40% Solutol® HS 15 (surfactant), and 30% Transcutol® P (cosurfactant) (w/w) with 80 mg valsartan/g excipients. The average droplet sizes of the optimized blank and drug-loaded SMEDDS formulations were 26.20 ± 1.43 and 33.34 ± 2.15 nm, and the melting points of them were 35.6 and 36.8 °C, respectively. The in vitro dissolution rate of optimal semi-solid SMEDDS was increased compared with commercial capsules, resulting in the 2.72-fold and 2.97-fold enhancement of Cmax and AUC0–t after oral administration in rats, respectively. These results indicated that the novel semi-solid SMEDDS formulation could potentially improve the oral bioavailability of valsartan, and the semi-solid SMEDDS was a desirable system than the traditional liquid SMEDDS because it was convenient for preparation, storage and transportation due to semi-solid state at room temperature and melted state at body temperature.

One-step self-assembled nanomicelles for improving the oral bioavailability of nimodipine.

Our study aimed to develop a self-assembled nanomicelle for oral administration of nimodipine (NIM) with poor water solubility. Using Solutol® HS15, the NIM-loaded self-assembled nanomicelles displayed a near-spherical morphology with a narrow size distribution of 12.57±0.21 nm (polydispersity index =0.071±0.011). Compared with Nimotop® (NIM tablets), the intestinal absorption of NIM from NIM nanomicelle in rats was improved by 3.13- and 2.25-fold in duodenum and jejunum at 1 hour after oral administration. The cellular transport of NIM nanomicelle in Caco-2 cell monolayers was significantly enhanced compared to that of Nimotop®. Regarding the transport pathways, clathrin, lipid raft/caveolae, and macropinocytosis mediated the cell uptake of NIM nanomicelles, while P-glycoprotein and endoplasmic reticulum/Golgi complex (ER/Golgi) pathways were involved in exocytosis. Pharmacokinetic studies in our research laboratory have showed that the area under the plasma concentration–time curve (AUC0–∞) of NIM nanomicelles was 3.72-fold that of Nimotop® via oral administration in rats. Moreover, the NIM concentration in the brain from NIM nanomicelles was dramatically improved. Therefore, Solutol® HS15-based self-assembled nanomicelles represent a promising delivery system to enhance the oral bioavailability of NIM.

Toxicity of Smokeless Tobacco Extract after 184-Day Repeated Oral Administration in Rats.

The use of smokeless tobacco (ST) is growing rapidly and globally. The consumption of ST is associated with an increased risk for developing chronic diseases, such as diabetes, hypercholesterolemia, and myocardial infarction, and has led to many public health problems. It is very important to access the toxicity of ST. This experiment presents data from 184-day toxicology studies in Sprague-Dawley (SD) rats designed to characterize the chronic effects of a smokeless tobacco extract (STE). The control group and treatment groups were matched for a range of nicotine levels. Animals were given STE by oral gavage with doses of 3.75 (low-dose), 7.50 (mid-dose) and 15.00 (high-dose) mg·nicotine/kg body weight/day for 184 days, followed by 30 days for recovery. Variables evaluated included body weights, feed consumption, clinical observations, clinical and anatomic pathology (including organ weights), and histopathology. Decreased body weights and organ weights (heart, liver and kidney) were found in animals in the mid-dose and high-dose groups. STE also showed moderate and reversible toxicity in esophagus, stomach, liver, kidney and lung.

Developmental toxicity of N-methylaniline following prenatal oral administration in rats.

The objective of the study was to assess prenatal toxicity of N-methylaniline (NMA) administered by gavage to pregnant female rats. Pregnant female rats were administered N-methylaniline in corn oil by gavage at daily doses of 0.8 mg/kg of body weight (b.w.), 4 mg/kg b.w., 20 mg/kg b.w. and 100 mg/kg b.w. from implantation (the 5th day post mating) to the day prior to the scheduled caesarean section (the 20th day of pregnancy). General behavior, body weight, food and water consumption, hematological, biochemical analyses and pathomorphological changes of the dams were recorded. All the females survived until the end of the study. The test substance was toxic to pregnant females, even at the lowest of the used doses, i.e., 0.8 mg/kg b.w./day. Lower weight gain during pregnancy and significantly higher NMA-dose-dependent absolute weight of the organs were noted in the exposed females. The females from the groups exposed at doses of 20 mg/kg b.w./day and 100 mg/kg b.w./day developed anemia and showed higher concentrations of free thyroxine (FT3) and free triiodothyronine (FT4) thyroid hormones. Total protein concentration exhibited an increase in all the exposed groups of females. In the prenatal toxicity study, administration of N-methylaniline throughout the embryonic and fetal periods produced embryotoxic effects at doses ranging 4-100 mg/kg b.w./day. Considering the data obtained in this study, it is reasonable to assume that N-methylaniline administered orally to pregnant rats is toxic for mothers even at a low dose of 0.8 mg/kg b.w./day. However, this dose was not associated with any significant effects to their offspring. This prenatal exposure level may be considered as no-observed-adverse-effect level (NOAEL) for the progeny and a dose of 4 mg/kg b.w./day as the lowest-observed-adverse-effect level (LOAEL) for the progeny.