Administration Of Oral Doses Research Articles

Tissue distribution of artemisinin in broiler chickens following single or multiple oral administration

Background: Artemisinin is commonly used for the treatment of malaria, but recently has been considered as a potential substance to control poultry coccidiosis. OBJECTIVES: The aim of the present study was to determine the tissue distribution of artemisinin following single or multiple oral administration of different doses in broiler chickens. METHODS: A total number of 390 one day old Ross broiler chicks were divided randomly into two main groups, in the first group 0, 1, 5, 25, 125, 250, 500 or 1000 mg/kg artemisinin as a single oral dose was administered on day 44, but the second group were treated with 0, 17, 34, 68 or 136 ppm artemisinin from day 8 to day 44. The HPLC system was used to determine the level of artemisinin in different tissue samples. Data were assessed using one way analysis of variance (ANOVA) followed by the Tukey’s test (p<0.05). RESULTS: Maximum concentrations of artemisinin were found in the liver of chickens in both groups in a dose dependent manner. While, the minimum level was determined in the brain and the kidney of chickens received multiple artemisinin administration; in the spleen of those chickens a single oral dose was administered. The concentration of artemisinin in the brain reached a plateau at 68 ppm in multiple administration and 125mg/kg at single dose, no shift was found with dose increment. CONCLUSIONS: It can be concluded that tissue accumulation of artemisinin is time and dose dependent. Moreover, redistribution, saturation effect and tissue selectivity were also observed.

Toxic Effects of Oral Administration Doses of Hydroxylated C&lt;SUB&gt;60&lt;/SUB&gt; Fullerene on Liver in Swiss Albino Mice

Toxic Effects of Oral Administration Doses of Hydroxylated C&lt;SUB&gt;60&lt;/SUB&gt; Fullerene on Liver in Swiss Albino Mice

Discovery of N-[Bis(4-methoxyphenyl)methyl]-4-hydroxy-2-(pyridazin-3-yl)pyrimidine-5-carboxamide (MK-8617), an Orally Active Pan-Inhibitor of Hypoxia-Inducible Factor Prolyl Hydroxylase 1–3 (HIF PHD1–3) for the Treatment of Anemia

The discovery of novel 4-hydroxy-2-(heterocyclic)pyrimidine-5-carboxamide inhibitors of hypoxia-inducible factor (HIF) prolyl hydroxylases (PHD) is described. These are potent, selective, orally bioavailable across several species, and active in stimulating erythropoiesis. Mouse and rat studies showed hematological changes with elevations of plasma EPO and circulating reticulocytes following single oral dose administration, while 4-week q.d. po administration in rat elevated hemoglobin levels. A major focus of the optimization process was to decrease the long half-life observed in higher species with early compounds. These efforts led to the identification of 28 (MK-8617), which has advanced to human clinical trials for anemia.

Neuroprotective Effect of a New 7,8-Dihydroxycoumarin-Based Fe2+/Cu2+ Chelator in Cell and Animal Models of Parkinson's Disease.

Disturbed iron homeostasis, often coupled to mitochondrial dysfunction, plays an important role in the progression of common neurodegenerative diseases such as Parkinson's disease (PD). Recent studies have underlined the relevance of iron chelation therapy for the treatment of these diseases. Here we describe the synthesis, chemical, and biological characterization of the multifunctional chelator 7,8-dihydroxy-4-((methylamino)methyl)-2H-chromen-2-one (DHC12). Metal selectivity of DHC12 was Cu2+ ∼ Fe2+ > Zn2+ > Fe3+. No binding capacity was detected for Hg2+, Co2+, Ca2+, Mn2+, Mg2+, Ni2+, Pb2+, or Cd2+. DHC12 accessed cells colocalizing with Mitotracker Orange, an indication of mitochondrial targeting. In addition, DHC12 chelated mitochondrial and cytoplasmic labile iron. Upon mitochondrial complex I inhibition, DHC12 protected plasma membrane and mitochondria against lipid peroxidation, as detected by the reduced formation of 4-hydroxynonenal adducts and oxidation of C11-BODIPY581/591. DHC12 also blocked the decrease in mitochondrial membrane potential, detected by tetramethylrhodamine distribution. DHC12 inhibited MAO-A and MAO-B activity. Oral administration of DHC12 to mice (0.25 mg/kg body weight) protected substantia nigra pars compacta (SNpc) neurons against MPTP-induced death. Taken together, our results support the concept that DHC12 is a mitochondrial-targeted neuroprotective iron-copper chelator and MAO-B inhibitor with potent antioxidant and mitochondria protective activities. Oral administration of low doses of DHC12 is a promising therapeutic strategy for the treatment of diseases with a mitochondrial iron accumulation component, such as PD.

Pharmacokinetics, toxicity, and cytochrome P450 modulatory activity of plumbagin.

BackgroundThe antimalarial activity of plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone), a naturally occurring naphthoquinone widely distributed in the Plumbaginaceae family has previously been demonstrated in vitro (good activity) and in vivo (weak activity). The aim of the study was to investigate the pharmacokinetic profile following a single oral dosing to explain inconsistency of results of the in vitro and in vivo antimalarial activities. In addition, toxicity profiles and potential of modulation of cytochrome P450 enzymes (CYP1A2 and CYP3A11) were also investigated.MethodsThe pharmacokinetics and toxicity of plumbagin were investigated in rats. The propensity of plumbagin to modulate the mRNA expression and activities of the two inducible forms of hepatic drug metabolizing enzyme cytochrome P450 (CYP450), i.e., CYP1A2 and CYP3A11, was investigated using microsomes prepared from mouse livers.ResultsAcute and subacute toxicity tests indicate low toxicity of plumbagin with maximum tolerated doses of 150 (single oral dose) and 25 (daily doses for 28 days) mg/kg body weight, respectively. The pharmacokinetic profile of plumbagin following a single oral dose of 100 mg/kg body weight suggests that delayed absorption and short residence time (median values of time to maximal concentration and elimination half-life = 9.63 and 5.0 h, respectively) in plasma. Plumbagin did not modulate mRNA expression and activities of CYP1A2 and CYP3A11.ConclusionsPlumbagin was well tolerated following oral dose administration in rats. Pharmacokinetic property of this compound may be a limiting factor that explains the weak antimalarial activity of plumbagin observed in animal models. Potential metabolic interaction with co-administered drugs that are metabolized by CYP1A2 or CYP3A11 are unlikely.

Clinical Pharmacokinetics and Pharmacodynamics of Febuxostat.

Febuxostat is a xanthine oxidoreductase inhibitor that has been developed to treat chronic gout. In healthy subjects, the pharmacokinetic parameters of febuxostat after multiple oral dose administration include an oral availability of about 85%, an apparent oral clearance (CL/F) of 10.5±3.4L/h and an apparent volume of distribution at steady state (V ss/F) of 48±23L. The time course of plasma concentrations follows a two-compartment model. The initial half-life (t ½) is approximately 2h and the terminal t ½ determined at daily doses of 40mg or more is 9.4±4.9h. Febuxostat is administered once daily. The maximum (peak) plasma concentrations are approximately 100-fold greater than the trough concentrations. Consequently, there is no significant accumulation of the drug during multiple dose administration. There are few data on the pharmacokinetics of febuxostat in patients with gout. While the pharmacokinetic parameters are not affected by mild to moderate hepatic impairment, there is no consensus on whether renal impairment has any effect on the pharmacokinetics of febuxostat. Febuxostat is extensively metabolised by oxidation (approximately 35%) and acyl glucuronidation (up to 40%); febuxostat acyl glucuronides are cleared by the kidney. In healthy subjects treated with multiple doses of febuxostat 10-240mg, the concentrations of serum urate are reduced by a maximum of about 80%. The percentage reduction in the concentrations of serum urate is slightly less in gouty patients than in healthy subjects.

Toxicological implications of Margaritaria discoidea aqueous seed extract on Na+, K+-ATPase specific activity, glucose and serum electrolytes level in wistar rats

The effect of aqueous seed extract of Margaritaria discoidea on Na+ K+ ATPase activity and toxicity studies of its seed extract were investigated in albino rats. The study involved oral administration of different doses of the aqueous extract to groups of male albino rats at 25, 50,100, and 200mg/kg body weight resulted in significant (p&lt;0.05) decrease in sodium, potassium and glucose levels while chloride and calcium ions showed a significant (p&lt;0.05) increase relative to control. The seed extract also showed significant (p&lt;0.05) decrease in Na+ K+ ATPase specific activity in a dose dependent manner relative to control. The median lethal dose (LD50) of this extract in mice was established at 316.2mg/kg body weight using probit of mortality. The results showed that the acute toxicity potency of the aqueous extract of the seeds was practically non-toxic. The study showed that seeds of Margaritaria discoidea could be toxic if not consumed in moderate quantities.

Andrographis paniculata: Dissolution investigation and pharmacokinetic studies of four major active diterpenoids after multiple oral dose administration in healthy Thai volunteers

Ethnopharmacological relevanceAndrographis paniculata is included in ‘The National List of Essential Herbal Drugs A.D. 1999’ of Thailand as an herbal drug for the treatment of common cold symptoms and non-infectious diarrhea. The therapeutic activities of A. paniculata are attributed to four major active diterpenoids: andrographolide (1), 14-deoxy-11, 12-didehydroandrographolide (2), neoandrographolide (3), and 14-deoxyandrographolide (4). However, the pharmacokinetic studies in humans of this plant were performed after a single oral dose administration and reported the parameters related to be of only 1. Aim of the studyThis study aims to determine the pharmacokinetic parameters of four major active diterpenoids after multiple oral dose administration of A. paniculata capsules in healthy volunteers. The dissolution testing of these four diterpenoids was also performed. Materials and methodThe dissolution testing of four major active diterpenoids was conducted in pH 1.2, pH 4.5, and pH 6.8 for 10–100min. The pharmacokinetic study of these active diterpenoids was designed as an open-label, multiple oral dose administration of A. paniculata capsules in 20 healthy Thai volunteers at 1:1 ratio of female and male. Each volunteer was given four A. paniculata capsules each time which contained 1, 2, 3, and 4 in the quantities of 32.64, 5.40, 3.60, and 3.84mg, respectively, three times a day for three consecutive days. On the fourth day, after the first dose of the day was administered, blood samples were collected at the predefined time points. The validated LC-MS/MS method was used to simultaneously determine the concentrations of these diterpenoids in the human plasma samples. The pharmacokinetic parameters of each active diterpenoid were determined. ResultsAll four major active diterpenoids have been completely dissolved in the simulated pH of gastrointestinal tract within 60min of dissolution. The dissolution profiles were found to be highest in pH 6.8 and lowest in pH 1.2, especially for 3. In the pharmacokinetic study, although 1 was administered at the highest dose among these four diterpenoids, 2 exhibited the highest maximum concentrations (Cmax) of 44.89ng/mL and area under the plasma concentration-time curve (AUC) of 128.17h×ng/mL. Compound 1 had the second highest Cmax and AUC as 32.41ng/mL and 55.23h×ng/mL, respectively. The relative systemic exposure, represented by the dose normalized AUC [(h×ng/mL)/(mg/kg)], of 2 was approximately 14 times higher than that of 1, while those of 3 and 4 were approximately 1.5 and 1.6 times higher, respectively. Cmax, AUC, apparent volume of distribution, and apparent clearance of 2 were found to be significant difference between female and male. However, when these parameters were calculated as dose normalized basis, no statistically significant difference was found. ConclusionThe four major active diterpenoids in the A. paniculata capsules were soluble in all studied dissolution media. The pharmacokinetic parameters of these active diterpenoids in the present study could be applied for dose optimization of A. paniculata product in order to obtain good therapeutic efficacy and reduce the possible side effects that may occur from different active diterpenoids in this medicinal plant.

Physiologically based pharmacokinetic–pharmacodynamic modeling to predict concentrations and actions of sodium‐dependent glucose transporter 2 inhibitor canagliflozin in human intestines and renal tubules

Canagliflozin is a recently developed sodium-glucose cotransporter (SGLT) 2 inhibitor that promotes renal glucose excretion and is considered to inhibit renal SGLT2 from the luminal side of proximal tubules. Canagliflozin reportedly inhibits SGLT1 weakly and suppresses postprandial plasma glucose, suggesting that it also inhibits intestinal SGLT1. However, it is difficult to measure the drug concentrations of these assumed sites of action directly. The pharmacokinetic-pharmacodynamic (PK/PD) relationships of canagliflozin remain poorly characterized. Therefore, a physiologically based pharmacokinetic (PBPK) model of canagliflozin was developed based on clinical data from healthy volunteers and it was used to simulate luminal concentrations in intestines and renal tubules. In small intestine simulations, the inhibition ratios for SGLT1 were predicted to be 40%-60% after the oral administration of clinical doses (100-300mg/day). In contrast, inhibition ratios of canagliflozin for renal SGLT2 and SGLT1 were predicted to be approximately 100% and 0.2%-0.4%, respectively. These analyses suggest that canagliflozin only inhibits SGLT2 in the kidney. Using the simulated proximal tubule luminal concentrations of canagliflozin, the urinary glucose excretion rates in canagliflozin-treated diabetic patients were accurately predicted using the renal glucose reabsorption model as a PD model. Because the simulation of canagliflozin pharmacokinetics was successful, this PBPK methodology was further validated by successfully simulating the pharmacokinetics of dapagliflozin, another SGLT2 inhibitor. The present results suggest the utility of this PBPK/PD model for predicting canagliflozin concentrations at target sites and help to elucidate the pharmacological effects of SGLT1/2 inhibition in humans. Copyright © 2016 John Wiley & Sons, Ltd.

EFFECT OF PHARMACOLOGICAL DOSES OF GARLIC AND OMEGA 3 ON GASTRIC LESIONS INDUCED BY ETHANOL IN MICE

ABSTRACTObjective: This work was designed to investigate and compare the possible protective effect of pharmacological doses of garlic and omega 3 againstgastric lesions induced by ethanol in mice.Methods: A total of 30 mice involved in the study were divided into five groups with 6 mice for each. Groups 1 (ulcer control) and 2 (normal control),Groups 3 (positive ulcer control treated with ranitidine 50 mg/kg), Groups 4 and 5 treated with garlic oil and omega 3 oil at doses 200 and 150 mg/kg,respectively. All groups treated orally by gastric gavage once daily for 14 days before starting gastric ulcer (GU) induction process by absolute ethanoladministration.Results: A treatment with garlic and omega 3 ameliorated the severity of gastric ulceration evidenced by reduced ulcer index area, increase %gastroprotection, increase mucus content, reduced erosions, and necrosis.Conclusion: Oral administration of pharmacological doses of garlic oil and omega 3 oil shows significant gastroprotection against GU models inducedby absolute ethanol confirmed by biochemical and histological data.Keywords: Gastric ulcer, Garlic, Omega 3, Gastroprotection.

Leveraging model-based study designs and serial micro-sampling techniques to understand the oral pharmacokinetics of the potent LTB4 inhibitor, CP-105696, for mouse pharmacology studies

1. Leukotriene B4 (LTB4) is a proinflammatory mediator important in the progression of a number of inflammatory diseases. Preclinical models can explore the role of LTB4 in pathophysiology using tool compounds, such as CP-105696, that modulate its activity. To support preclinical pharmacology studies, micro-sampling techniques and mathematical modeling were used to determine the pharmacokinetics of CP-105696 in mice within the context of systemic inflammation induced by a high-fat diet (HFD).2. Following oral administration of doses > 35 mg/kg, CP-105696 kinetics can be described by a one-compartment model with first order absorption. The compound’s half-life is 44–62 h with an apparent volume of distribution of 0.51–0.72 L/kg. Exposures in animals fed an HFD are within 2-fold of those fed a normal chow diet. Daily dosing at 100 mg/kg was not tolerated and resulted in a >20% weight loss in the mice.3. CP-105696’s long half-life has the potential to support a twice weekly dosing schedule. Given that most chronic inflammatory diseases will require long-term therapies, these results are useful in determining the optimal dosing schedules for preclinical studies using CP-105696.

Effect of combined oral doses of Δ(9)-tetrahydrocannabinol (THC) and cannabidiolic acid (CBDA) on acute and anticipatory nausea in rat models.

The purpose of this study was to evaluate the potential of oral combined cannabis constituents to reduce nausea. The objective of this study was to determine the effect of combining subthreshold oral doses of Δ(9)-tetrahydrocannabinol (THC) and cannabidiolic acid (CBDA) on acute and anticipatory nausea in rat models of conditioned gaping. The potential of intragastric (i.g.) administration of THC, CBDA, or combined doses, to interfere with acute nausea-induced conditioned gaping (acute nausea) or the expression of contextually elicited conditioned gaping (anticipatory nausea), was evaluated. For acute nausea, i.g. administration of subthreshold doses of THC (0.5 and 1mg/kg) or CBDA (0.5 and 1μg/kg) significantly suppressed acute nausea-induced gaping, whereas higher individual doses of both THC and CBDA were maximally effective. Combined i.g. administration of higher doses of THC and CBDA (2.5mg/kg THC-2.5μg/kg CBDA; 10mg/kg THC-10μg/kg CBDA; 20mg/kg THC-20μg/kg CBDA) also enhanced positive hedonic reactions elicited by saccharin solution during conditioning. For anticipatory nausea, combined subthreshold i.g. doses of THC (0.1mg/kg) and CBDA (0.1μg/kg) suppressed contextually elicited conditioned gaping. When administered i.g., THC was effective on its own at doses ranging from 1 to 10mg/kg, but CBDA was only effective at 10μg/kg. THC alone was equally effective by intraperitoneal (i.p.) and i.g. administration, whereas CBDA alone was more effective by i.p. administration (Rock et al. in Psychopharmacol (Berl) 232:4445-4454, 2015) than by i.g. administration. Oral administration of subthreshold doses of THC and CBDA may be an effective new treatment for acute nauseaandanticipatory nausea and appetite enhancement in chemotherapy patients.

Abstract 350: Visualizing alectinib distribution in mice brain by using MALDI mass spectrometry imaging technique

Abstract [Introduction] In the development of anticancer drug, measurement of drug concentration in target tissue has been thought to be crucial for predicting its efficacy and safety. However, measuring homogenized tissue by using quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) completely loss the spatial information of the compound in a target tissue. Mass spectrometry imaging (MSI) has been recently applied as innovative tools to detect pharmaceutical distributions in heterogeneous targets; however, it still needs to be improved in quantitative capability or reproducibility. [Purpose] We propose quantitative approach for MSI (qMSI) that administere matrix-assisted laser desorption ionization (MALDI)-MSI, concurrently with LC-MS/MS by using serial sections. We applied qMSI for visualizing spatial distribution of alectinib, novel ALK inhibitor, in mouse brain and examined the effect of MDR1 (p-glycoprotein) on the pharmacokinetic profiles in FVB and Mdr1a/b knockout mice. [Method] Pharmacokinetic study of alectinib was conducted in FVB and Mdr1a/b KO mice. Plasma, cerebrospinal fluid (CSF) and brain tissue were collected at 1, 1.5, 2, and 4 hours after a single oral administration dose of 4 and 20 mg/kg. The concentration of alectinib in plasma, CSF and brain tissue sections was measured by LC-MS/MS. The distribution of alectinib in mice brain tissue section was visualized by qMSI that we established. [Results] Developing qMSI showed the brain distribution of alectinib in the range from 1.2 to 952.6 pg/mm2 per each section, and the results made with qMSI were in excellent agreement with the complementary measurements by using laser-micro dissection to verify the exposure level. While plasma alectinib concentrations had no difference between both mice, the diffuse alectinib distributions in brain were observed in Mdr1a/b knockout compared with that in FVB mice. The dominant localization of alectinib in choroid plexus and brain blood vessels of FVB mice was observed by 20 μm resolution MSI analysis. [Conclusion] Our qMSI technique is expected to contribute to the development of anticancer drugs and translational research by visualizing drug distribution in target organs and tumors. Citation Format: Hiroaki Aikawa, Mitsuhiro Hayashi, Shoraku Ryu, Makiko Yamashita, Naoto Ohtsuka, Masanobu Nishidate, Akinobu Hamada. Visualizing alectinib distribution in mice brain by using MALDI mass spectrometry imaging technique. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 350.

Pharmacokinetics After Single Ascending Dose, Food Effect, and Safety of Sacubitril/Valsartan (LCZ696), an Angiotensin Receptor and Neprilysin Inhibitor, in Healthy Japanese Subjects.

LCZ696 (sacubitril/valsartan) is a novel angiotensin receptor neprilysin inhibitor (ARNI) that has been developed for treatment of heart failure patients with reduced ejection fraction and approved in the US, Europe, and many other countries. This randomized, placebo-controlled study was conducted in healthy Japanese male subjects (N=50) to assess the pharmacokinetics and safety of single ascending oral doses (20-600mg) of LCZ696. Food effect was also evaluated following administration of 200mg dose. Plasma and urine samples from 40 subjects receiving LCZ696 were collected to assess pharmacokinetics of LCZ696 analytes (sacubitril, sacubitrilat, and valsartan). Following single oral dose administration of LCZ696, sacubitril and valsartan rapidly appeared in systemic circulation with a dose-linear increase in the exposure to the LCZ696 analytes. Of the administered dose, approximately 0.85%, 54.0%, and 8.19% of sacubitril, sacubitrilat, and valsartan, respectively, were recovered in urine. Food reduced AUC of sacubitril, sacubitrilat, and valsartan by 21, 8, and 40%, respectively, and C max by 72, 27, and 51%, respectively. Single oral doses of up to 600mg of LCZ696 were safe and generally well tolerated in healthy Japanese male subjects.

Pharmacokinetics of Roflumilast and Its Active Metabolite Roflumilast N-Oxide in Healthy Chinese Subjects After Single and Multiple Oral Doses

Roflumilast is a selective, oral phosphodiesterase 4 inhibitor approved for the treatment of severe chronic obstructive pulmonary disease. The aim of this study was to evaluate the pharmacokinetics of roflumilast and roflumilast N-oxide in healthy Chinese subjects, and the effects of gender and food on their respective pharmacokinetic profiles. 36 healthy Chinese subjects were recruited in a randomized, single-center, open-label, parallel group study and assigned to 0.25-, 0.375-, and 0.5-mg dose groups. The single-dose pharmacokinetic studies in fasting condition were carried out in all groups. Moreover, the food effect study and multiple-dose study were conducted in 0.375-mg dose group. Serial blood samples were collected over 168h after dosing, and plasma concentrations of roflumilast and roflumilast N-oxide were determined using a validated LC-MS/MS method. After oral administration of single doses of 0.25, 0.375 and 0.5mg of roflumilast under fasting condition, the mean AUC0-72h for roflumilast was 21.7±8.3, 29.8±8.3 and 54.2±21.3ng·h/mL, respectively. Meanwhile the mean AUC0-168h for roflumilast N-oxide was 290±103, 385±107 and 673±245ng·h/mL, respectively. In the steady state after the multi-dose administration, the exposure to roflumilast in the subjects increased 20-40%, and the exposure to roflumilast N-oxide increased about 169%, compared to the single-dose administration. No statistically significant effect of gender on the disposition of roflumilast and roflumilast N-oxide was observed. Food had no effect on systemic exposure to roflumilast and roflumilast N-oxide in the subjects, but delayed the T max of roflumilast by 0.9h and reduced the C max of roflumilast by approximately 20%. Based upon between-study comparison, peak and systemic exposure of roflumilast and roflumilast N-oxide were higher in Chinese than that in Caucasian subjects after oral administration of the same dose (i.e., 0.25 and 0.5mg). It implies that the therapeutic dose for Chinese patients may be different from that for Caucasians, warranting further investigation.

Ultrasensitive quantification of the CYP2E1 probe chlorzoxazone and its main metabolite 6-hydroxychlorzoxazone in human plasma using ultra performance liquid chromatography coupled to tandem mass spectrometry after chlorzoxazone microdosing.

Chlorzoxazone is a probe drug to assess cytochrome P450 (CYP) 2E1 activity (phenotyping). If the pharmacokinetics of the probe drug is linear, pharmacologically ineffective doses are sufficient for the purpose of phenotyping and adverse effects can thus be avoided. For this reason, we developed and validated an assay for the ultrasensitive quantification of chlorzoxazone and 6-hydroxychlorzoxazone in human plasma. Plasma (0.5mL) and liquid/liquid partitioning were used for sample preparation. Extraction recoveries ranged between 76 and 93% for both analytes. Extracts were separated within 3min on a Waters BEH C18 Shield 1.7μm UPLC column with a fast gradient consisting of aqueous formic acid and acetonitrile. Quantification was achieved using internal standards labeled with deuterium or (13)C and tandem mass spectrometry in the multiple reaction monitoring mode using negative electrospray ionization, which yielded lower limits of quantification of 2.5pgmL(-1), while maintaining a precision always below 15%. The calibrated concentration ranges were linear for both analytes (2.5-1000pgmL(-1)) with correlation coefficients of >0.99. Within-batch and batch-to-batch precision in the calibrated ranges for both analytes were <15% and <11% and plasma matrix effects always were below 50%. The assay was successfully applied to assess the pharmacokinetics of chlorzoxazone in two human volunteers after administration of single oral doses (2.5-5000μg). This ultrasensitive assay allowed the determination of chlorzoxazone pharmacokinetics for 8h after microdosing of 25μg chlorzoxazone.

Serum concentration of Artemisinin after single and chronic oral dose administration in broiler chickens

Although preliminary studies have shown the anticoccidial effects of Artemisinin in broiler chickens, there are no proofs of its pharmacokinetics. The objective of this study was to determine the serum concentration of Artemisinin after single and multiple oral administration in broiler chickens. A total of 390 one-day-old healthy Ross 308 chickens were divided randomly into two groups. In the first group, single oral doses of 0, 1, 5, 25, 125, 250, 500 and 1000 mg/kg Artemisinin were given on day 44, and in the second group 0, 17, 34, 68 and 136 ppm of Artemisinin were given chronically in the diet over a 36-day period. An HPLC system with UV detector was used to determine serum level of Artemisinin. Data were presented as Mean ± SE and analyzed using the linear mixed model (p < 0.05). The results showed that in both groups the serum levels of Artemisinin were generally very low and there were no significant differences between multiple and single dose administration groups or between different doses in each group (p < 0.05). The serum levels of Artemisinin in the chickens that had received single doses were in the range of 25.38 ± 0.15 to 42.27 ± 12.04 ng/ml and 24.68 ± 0.12 to 29.24 ± 1.72 ng/ml for those that had received chronic doses. It can be concluded that serum level of Artemisinin administered orally to the chickens as single or chronic doses is low which seems to be due to low oral absorption and metabolism induction and thus, can have high therapeutic index and good anticoccidial properties.

Development and validation of an LC-MS/MS method for simultaneous quantification of levodopa and MD01 in rat plasma and its application to a pharmacokinetic study of mucuna pruriens extract.

Mucuna pruriens, an ancient Indian herbal medicine containing levodopa, is widely used for Parkinson's disease. In order to simultaneously determine levodopa and 1,1-dimethyl-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (MD01) in rat plasma, an improved LC-MS/MS method was developed and validated for a pharmacokinetic study in rats orally administered levodopa or Mucuna pruriens extract (MPE). Elimination of matrix effect and improvement of extraction recovery were achieved through systematic optimization of reversed-phase and hydrophilic interaction chromatographic conditions together with sample clean-up procedures. A satisfactory chromatographic performance was obtained with a Thermo Aquasil C18 column (50 × 2.1 mm, 3 µm) using acetonitrile and water containing 0.2% formic acid as mobile phases. Futhermore, sodium metabisulfite and formic acid were used as stabilizers in neat solutions as well as rat plasma. The method was validated in a dynamic range of 20.0-10,000 ng/mL for levodopa and MD01; the intra- and inter-day precision and accuracy were acceptable. The method was successfully utilized to determine the levodopa level in plasma samples of rats administered levodopa or MPE. Pharmacokinetic results showed that an increase in the AUC of levodopa was observed in rats following oral administration of multiple doses of MPE. Copyright © 2016 John Wiley & Sons, Ltd.

Pharmacokinetics of isochlorgenic acid C in rats by HPLC-MS: Absolute bioavailability and dose proportionality

Ethnopharmacological relevanceIsochlorgenic acid C (IAC), one of the bioactive compounds of Lonicera japonica, exhibited diverse pharmacological effects. However, its pharmacokinetic properties and bioavailability remained unresolved. Aim of the studyTo determine the absolute bioavailability in rats and the dose proportionality on the pharmacokinetics of single oral dose of IAC. Materials and methodsA validated HPLC-MS method was developed for the determination of IAC in rat plasma. Plasma concentration versus time data were generated following oral and intravenous dosing. The pharmacokinetic analysis was performed using DAS 3.0 software analysis. Absolute bioavailability in rats was determined by comparing pharmacokinetic data after administration of single oral (5, 10 and 25mgkg−1) and intravenous (5mgkg−1) doses of IAC. The dose proportionality of AUC(0-∞) and Cmax were analyzed by linear regression. ResultsExperimental data showed that absolute oral bioavailability of IAC in rats across the doses ranged between 14.4% and 16.9%. The regression analysis of AUC(0-∞) and Cmax at the three doses (5, 10 and 25mgkg−1) indicated that the equations were y=35.23x+117.20 (r=0.998) and y=121.03x+255.74 (r=0.995), respectively. ConclusionsA new HPLC-MS method was developed to determine the bioavailability and the dose proportionality of IAC. Bioavailability of IAC in rats was poor and both Cmax and AUC(0-∞) of IAC had a positive correlation with dose. Evaluation of the pharmacokinetics of IAC will be useful in assessing concentration-effect relationships for the potential therapeutic applications of IAC.

Antithrombotic activity of oral administered low molecular weight fucoidan from Laminaria Japonica

IntroductionFucoidans extracted from brown algae have been documented to have excellent antithrombotic activity when administered by either intravenous or subcutaneous route in animal models. However, it is unknown if the fucoidans also have antithrombotic activity when administered orally, a highly desirable feature of oral antithrombotic agents. In the present study, we compared the oral absorption, bioavailability and antithrombotic activity of two fucoidan fractions from Laminaria japonica with different molecular weight by oral administration in an electricity induced arterial thrombosis model and the underlying molecular mechanisms. Results and conclusionsAfter a single dose of oral administration, the fucoidan content in plasma and urine in rats was assessed using the reverse-phased HPLC analysis of 1-phenyl-3-methyl-5-pyrazolone (PMP)-labeled fucose. The fucose content in the low molecular weight (LMW) fucoidan-treated rats increased up to 2-fold and peaked at 15h, indicating that the LMW fucoidan had much better absorption and bioavailability than the MMW fucoidan in vivo. Oral administration of the LMW fucoidan at 400 and 800mg/kg for 30days inhibited the arterial thrombosis formation effectively induced by electrical shock in rats, accompanied by moderate anticoagulation activity, regulation on TXB2 and 6-keto-PGF1α, significant antiplatelet activity and effective fibrinolysis. The LMW fucoidan showed better oral absorption and antithrombotic activity in addition to different antithrombotic mechanisms compared to those of the medium molecular weight (MMW) fucoidan. Thus, the LMW fucoidan has a potential to become an oral antithrombotic agent.