Effects of Three Kinds of Carbohydrate Pharmaceutical Excipients-Fructose, Lactose and Arabic Gum on Intestinal Absorption of Gastrodin through Glucose Transport Pathway in Rats.

BACKGROUND: Some glucoside drugs can be transported via intestinal glucose transporters (IGTs), and the presence of carbohydrate excipients in pharmaceutical formulations may influence the absorption of them. This study, using gastrodin as probe drug, aimed to explore the effects of fructose, lactose, and arabic gum on intestinal drug absorption mediated by the glucose transport pathway. METHODS: The influence of fructose, lactose, and arabic gum on gastrodin absorption was assessed via pharmacokinetic experiments and single-pass intestinal perfusion. The expression of sodium-dependent glucose transporter 1 (SGLT1) and sodium-independent glucose transporter 2 (GLUT2) was quantified via RT‒qPCR and western blotting. Alterations in rat intestinal permeability were evaluated through H&E staining, RT‒qPCR, and immunohistochemistry. RESULTS: Fructose reduced the area under the curve (AUC) and peak concentration (Cmax) of gastrodin by 42.7% and 63.71%, respectively (P < 0.05), and decreased the effective permeability coefficient (Peff) in the duodenum and jejunum by 58.1% and 49.2%, respectively (P < 0.05). SGLT1 and GLUT2 expression and intestinal permeability remained unchanged. Lactose enhanced the AUC and Cmax of gastrodin by 31.5% and 65.8%, respectively (P < 0.05), and increased the Peff in the duodenum and jejunum by 33.7% and 26.1%, respectively (P < 0.05). SGLT1 and GLUT2 levels did not significantly differ, intestinal permeability increased. Arabic gum had no notable effect on pharmacokinetic parameters, SGLT1 or GLUT2 expression, or intestinal permeability. CONCLUSION: Fructose, lactose, and arabic gum differentially affect intestinal drug absorption through the glucose transport pathway. Fructose competitively inhibited drug absorption, while lactose may enhance absorption by increasing intestinal permeability. Arabic gum had no significant influence.

Gastrodin, a Promising Natural Small Molecule for the Treatment of Central Nervous System Disorders, and Its Recent Progress in Synthesis, Pharmacology and Pharmacokinetics.

Gastrodia elata Blume is a traditional medicinal and food homology substance that has been used for thousands of years, is mainly distributed in China and other Asian countries, and has always been distinguished as a superior class of herbs. Gastrodin is the main active ingredient of G. elata Blume and has attracted increasing attention because of its extensive pharmacological activities. In addition to extraction and isolation from the original plant, gastrodin can also be obtained via chemical synthesis and biosynthesis. Gastrodin has significant pharmacological effects on the central nervous system, such as sedation and improvement of sleep. It can also improve epilepsy, neurodegenerative diseases, emotional disorders and cognitive impairment to a certain extent. Gastrodin is rapidly absorbed and widely distributed in the body and can also penetrate the blood-brain barrier. In brief, gastrodin is a promising natural small molecule with significant potential in the treatment of brain diseases. In this review, we summarised studies on the synthesis, pharmacological effects and pharmacokinetic characteristics of gastrodin, with emphasis on its effects on central nervous system disorders and the possible mechanisms, in order to find potential therapeutic applications and provide favourable information for the research and development of gastodin.

Elucidation of the Transport Mechanism of Puerarin and Gastrodin and Their Interaction on the Absorption in a Caco-2 Cell Monolayer Model.

Puerarin (PUR) and gastrodin (GAS) are often used in combined way for treating diseases caused by microcirculation disorders. The current study aimed to investigate the absorption and transportation mechanism of PUR and GAS and their interaction via Caco-2 monolayer cell model. In this work, the concentration in Caco-2 cell of PUR and GAS was determined by HPLC method. The bidirectional transport of PUR and GAS and the inhibition of drug efflux including verapamil and cyclosporine on the transport of these two components were studied. The mutual influence between PUR and GAS, especially the effect of the latter on the former of the bidirectional transport were also investigated. The transport of 50 µg·mL-1 PUR in Caco-2 cells has no obvious directionality. While the transport of 100 and 200 µg·mL-1 PUR presents a strong directionality, and this directionality can be inhibited by verapamil and cyclosporine. When PUR and GAS were used in combination, GAS could increase the absorption of PUR while PUR had no obvious influence on GAS. Therefore, the compatibility of PUR and GAS is reasonable, and GAS can promote the transmembrane transport of PUR, the effect of which is similar to that of verapamil.

Enhanced Solubility and Permeability of Salicis cortex Extract by Formulating as a Microemulsion.

A microemulsion system was developed and investigated as a novel oral formulation to increase the solubility and absorption of Salicis cortex extract. This extract possesses many pharmacological activities, in particular, it is beneficial for back pain and osteoarthritic and rheumatic complaints. In this work, after qualitative and quantitative characterization of the extract and the validation of an HPLC/diode array detector analytical method, solubility studies were performed to choose the best components for microemulsion formulation. The optimized microemulsion consisted of 2.5 g of triacetin, as the oil phase, 2.5 g of Tween 20 as the surfactant, 2.5 g of labrasol as the cosurfactant, and 5 g of water. The microemulsion was visually checked, characterized by light scattering techniques and morphological observations. The developed formulation appeared transparent, the droplet size was around 40 nm, and the ζ-potential result was negative. The maximum loading content of Salicis cortex extract resulted in 40 mg/mL. Furthermore, storage stability studies and an in vitro digestion assay were performed. The advantages offered by microemulsion were evaluated in vitro using artificial membranes and cells, i.e., parallel artificial membrane permeability assay and a Caco-2 model. Both studies proved that the microemulsion was successful in enhancing the permeation of extract compounds, so it could be useful to ameliorate the bioefficacy of Salicis cortex.

Pharmacokinetic and tissue distributions study of adenosine, 4-hydroxybenzyl alcohol and Parishin C from Gastrodia elata extract in rats.

The plant Gastrodia elata is a type of the orchid plant Gastrodia elata Bl. which contains glycosides, phenols, polysaccharides, sterols, and organic acids and a variety of active ingredients are proved to have certain pharmacological activities. To understand the process in the body of Gastridua elata, we used HPLC to study pharmacokinetics and tissue distributions of adenosine, 4-hydroxybenzyl alcohol and Parishin C in rats. The results showed that the three ingredients could be detected in plasma and different organizations at various time points. There was no significant difference in systemic clearance at three ingredients and it may be show that the three ingredients distributed (0.475±0.025, 0.518±0.033, 0.699±0.051) quickly and eliminated (5.37±0.87, 4.54±0.69, 5.34±0.82) slowly in plasma. There was the highest content of adenosine in spleen, followed by liver and lung. The highest content of 4-hydroxybenzylacohol in liver, and was higher in spleen. Parishin C was highest in heart, followed by liver and spleen. It is obvious that the contents of three ingredients are all higher in liver. The trends of the three ingredients' contents in G. rhizome extract were consistent with the contents in the plasma after intravenous administration.

Simultaneous determination of ferulic acid and gastrodin of Tianshu Capsule in rat plasma by ultra-fast liquid chromatography with tandem mass spectrometry and its application to a comparative pharmacokinetic study in normal and migraine rats.

Tianshu Capsule, consisting of Ligusticum chuanxiong Hort and Gastrodia elata Blume, is a widely used Traditional Chinese Medicine preparation for the treatment of migraine. Ferulic acid and gastrodin are main active constituents in Ligusticum chuanxiong Hort and Gastrodia elata Blume, and have been used as marker components for quality control of Tianshu Capsule. In this study, a selective, sensitive, and reliable ultra-fast liquid chromatography with tandem mass spectrometry method was developed for simultaneous determination of ferulic acid and gastrodin in rat plasma using geniposide as internal standard. The plasma samples were extracted by protein precipitation with methanol after acidification and separated on a Shim-Pack XR-ODS C18 column (75 × 3.0 mm, 2.2 µm) using gradient elution with a mobile phase consisting of water (containing 0.1% formic acid) and acetonitrile at a flow rate of 0.6 mL/min. Detection was performed on 3200 QTRAP mass spectrometry equipped with turbo ion spray source in negative ionization mode. Validation parameters were within acceptable ranges. The validated method was applied to compare the pharmacokinetic profiles of ferulic acid and gastrodin in normal and migraine rats. Our results showed that there were remarkable differences in the pharmacokinetic properties of the analytes between the normal and migraine groups.

Relative tissue distribution and excretion studies of gastrodin and parishin from powder and extract of Gastrodiae Rhizoma in rat by UHPLC-ESI-MS/MS.

New research has indicated that Gastrodiae Rhizome (GR) has potential anti-diabetic and anti-asthmatic effects in mouse models. On the basis of our previous study of the relative bioavailability of gastrodin (GAS) and parishin (PA) from extract and powder of GR, we performed further research on the tissue distribution and excretion of the two analytes. A reliable bioanalytical method for the quantification of GAS and PA in rat tissues and excretion is required. Chromatographic separation was carried out on a gradient mobile phase of acetonitrile-water with 0.1% formic acid. Calibration curves (1/x2 weighted) offered satisfactory linearity (r2 > 0.9835) within 100-3000 ng mL-1 for GAS and (r2 > 0.9862) within 10-1000 ng mL-1 for PA. The relative standard deviations of the intra-day and inter-day precision were all <14.98%, whilst the relative errors of the intra-day and inter-day accuracy were all within ±14.71%. The matrix effect and recovery values were satisfactory in all of the biological matrices examination. The data of relative differences in tissue distribution and excretion of GAS and PA from powder and extract of GR indicated that higher bioavailabilities for GAS and PA were obtained when a dosage of 4 g kg-1 GR powder was used.

An Optimized and Sensitive Pharmacokinetic Quantitative Method of Investigating Gastrodin, Parishin, and Parishin B, C and E in Beagle Dog Plasma using LC-MS/MS after Intragastric Administration of Tall Gastrodia Capsules.

Gastrodia elata Blume, called Tianma in China, has been widely used to treat headaches, convulsions and epilepsy for thousands of years. In the present study, a series of optimizations were employed to develop a rapid, sensitive, and reliable high-performance liquid chromatography-triple quadrupole mass spectrometry method, which was then used for the simultaneous determination of gastrodin, parishin, parishin B, parishin C and parishin E in beagle dog plasma after intragastric administration of tall Gastrodia capsules (Tianma brand). The chromatographic separation was achieved on a C18 column with gradient elution by using a mixture of 0.4% formic acid aqueous solution and acetonitrile as the mobile phase at a flow rate of 0.15 mL/min. A tandem mass spectrometric detection was conducted using multiple-reaction monitoring (MRM) via electrospray ionization (ESI) source in negative ionization mode. Samples were pre-treated by a single-step protein precipitation with methanol, and bergenin was used as internal standard (IS). Under the optimized conditions, the lower limit of quantification (LLOQ) was 0.10 ng/mL for gastrodin, 0.40 ng/mL for parishin B, 0.02 ng/mL for parishin E and 0.20 ng/mL for parishin and parishin C, all of which previously were the highest levels of sensitivity. The methods were optimized for selectivity, calibration curves, accuracy and precision. Extraction recoveries, matrix effects and stability were within acceptable ranges. Pharmacokinetic parameters of the tested substances were also quantitatively determined. Finally, a possible metabolic pathway was induced based on correlations obtained from quantitative and qualitative data analysis in vivo.

[Effect of combination of gastrodia and uncaria on pharmacokinetics of gastrodin and rhynchophylline].

To investigate the effect of the combination of gastrodia and uncaria on the pharmacokinetics of gastrodin and rhynchophylline, and determine their pharmacokinetic parameters after administration of the combination of gastrodia and uncaria at the ratio of 12∶9. Compared with uncaria group or gastrodia group, Cmax and AUC of both gastrodin and rhynchophylline were significantly increased, and tmax was retroceded by 1.5 h for rhynchophylline and 0.25 h for gastrodin. The change of tmax resulted in a 1.25 h difference in the peak time between gastrodin and rhynchophylline , which was the same between them. Uncaria shows a more effect in suppressing hyperactive Yang, while gastrodia has a balancing effect by nourishing Yin and suppressing hyperactive Yang. As a result, gastrodia could exert the effect in nourishing Yin and suppressing effect of uncaria, which could avoid the deficiency of Yang affecting Yin due to mono-treatment of uncaria. On one hand, the enhanced AUC and Cmax of gastrodin could increase the average plasma drug concentration of gastrodin, and remedy the losing effect of uncaria at the early stage; On the other hand, the increased AUC and Cmax of rhynchophylline could make up the quick elimination of gastrodia in vivo at the late stage. Their combination could lead to an increased anti-hypertensive effect with the balance of Yin and Yang. They showed unique advantages compared with simple dosage increase of western medicines. The results were consistent with the principle of TCM treatment for the hypertension due to hyperactivity of the liver Yang. In short, this study gives a good pharmacokinetic explanation of the balance of Yin and Yang and TCM treatment for both symptoms and root cause.

Population pharmacokinetics of inhaled fluticasone furoate and vilanterol in adult and adolescent patients with asthma.

OBJECTIVES: Population pharmacokinetic (PK) methods were used to characterize the PK of fluticasone furoate (FF) and vilanterol (VI) in patients with asthma following once daily inhaled FF/VI and FF and to identify significant covariates that impact the PK. MATERIALS AND METHODS: Four of the five studies in the meta-analysis were conducted in patients with asthma (> 90%), the fifth in healthy subjects. FF data were described by a two-compartment model with first order absorption and elimination. VI data were described by a three-compartment model with zero-order absorption and first order elimination. RESULTS: Race was a significant covariate on inhaled clearance (CL/F) of FF PK. AUC(0-24) for Asian patients was on average 33 - 53% higher than for non-Asians. Race was also a significant covariate on VI PK, with lower (81%) central volume of distribution (Vc/F) for Asian patients compared with non-Asians; VI C(max) was 220 - 287% higher in Asian patients. Treatment (combination or monotherapy), predicted percentage FEV(1), and other demographic variables did not influence the PK of FF or VI. CONCLUSIONS: Combination of FF/VI does not appear to affect the PK of FF or VI. The effect of race on PK of FF or VI does not have impact on dosage adjustments for FF/VI in East Asian patients with asthma.

Pharmacokinetics of fluticasone furoate, umeclidinium, and vilanterol as a triple therapy in healthy volunteers.

OBJECTIVE: Two single-center, four-way, single-dose, crossover studies assessed the systemic exposure, systemic pharmacodynamics (PD), and safety profile of the closed triple fluticasone furoate/ umeclidinium/vilanterol (FF/UMEC/VI) therapy compared with dual therapies. These are the first studies where pharmacokinetic (PK) profile assessment was possible for this inhaled triple fixed-dose combination product. METHODS: Healthy volunteers were randomized to receive 4 consecutive inhalations (each administered as a single dose) via a single ELLIPT® dry powder inhaler: in study 1 (CTT116415/NCT01691547), FF/UMEC/VI at total doses of 400/500/100 µg, FF/UMEC 400/500 µg, UMEC/VI 500/100 µg, or FF/VI 400/100 µg; in study 2 (200587/NCT01894386), FF/UMEC/VI at total doses of 400/500/100 µg or 400/250/100 µg, FF/VI 400/100 µg, or UMEC/VI 250/100 µg. PK and PD parameters and safety were assessed. RESULTS: Of 88 subjects, 95% completed both studies and received all planned treatments. Total systemic exposure was similar for FF, UMEC, and VI when administered as a triple therapy compared with FF/VI and UMEC/VI. No clinically significant systemic PD findings were detected. The incidence of adverse events was low and similar across treatment arms. CONCLUSIONS: Systemic exposure to all three components of the closed triple therapy, following single-dose delivery, was similar to that seen with the dual therapies FF/VI and UMEC/VI. The delivered lung dose and safety profile of all three agents, delivered via a single inhaler, are expected to be similar to those of the dual therapies.

[Pharmacokinetic study on combined application of gastrodin and puerarin in rats].

To establish a HPLC method for simultaneously determining plasma concentrations of gastrodin (Gas) and its metabolites hydroxybenzyl alcohol (HBA), puerarin (Pur) and internal standard (IS) p-hydroxyphenylethanol (Tyr) in rats and studying the pharmacokinetic process and interactions of gastrodin and puerarin after single and combined intravenous injection and oral administration. With Tyr as the internal standard, plasma samples were processed with methanol for protein precipitation, supernatant was dried with N2, and residues were re-dissolved with acetonitrile-0.05% phosphoric acid (20: 80). Chromatography was carried out on an Agilent ZORBAX SB-Aq C18 column (4.6 mm x 250 mm, 5 µm), with acetonitrile-0.05% phosphoric acid as the gradient mobile phase for the gradient elution. The UV detector wavelength was set at 221 nm for Gas HBA and IS and 250 nm for Pur. After the single or combined administration of Gas and Pur, their plasma concentrations in rats were detected. WinNonlin 5.2 pharmacokinetic software and SPSS 17. 0 software were used to respectively calculate pharmacokinetic parameters of each group, make a statistical analysis and compare the pharmacokinetic processes of Gas and Pur after the single or combined administration. According to the results, the absolute recoveries between low, media and high concentrations of Gas, HBA and Pur and IS as well as Tyr were more than 77.20%, with a good linearity (r > 0.999 6, n = 5) for Gas, HBA and Pur within concentration ranges of 0.10-101, 0.03-7.58 and 0.05-5.98 mg xL ('1) respectively. The lower limits of quantification for Gas, HBA and Pur were 0.10, 0.03, 0.05 mg x L(-1), respectively. Their in-ra-day and inter-day precisions were less than 12% with the accuracy between 85. 1% -1 10. %. All of the three substances and IS were stable during the whole analysis process. The findings showed significant differences in the main in vivo pharmacokinetic parame-ers in rats (AUC, C.(max) T,½ T.(max) MRT) after the single and combined administration of Gas and Pur. Either after the oral adminis-ration or after the intravenous injection, parameters showed a lower clearance rate ( L) longer mean residence time ( RT) and higher relative bioavailability, especially after the oral administration. Specifically, the relative bioavailability of the combined oral ad-inistration of Pur was 10. 7 times of that of the single administration, while that of Gas was 1. times of that of the single administra-ion. The combined administration of Gas and Pur can promote the absorption, decrease the elimination rate and prolong the mean resi-ence time. The method is simple and accurate and can be applied in the simultaneous determination of plasma concentrations of Gas, HBA and Pur in rats and the pharmacokinetic studies.

A repeat-dose thorough QT study of inhaled fluticasone furoate/vilanterol combination in healthy subjects.

AIMS: This study was designed as a thorough QT (TQT) study to evaluate the effects of fluticasone furoate (FF)/vilanterol (VI) in healthy subjects. Supportive data from a TQT study conducted with FF are also presented. METHODS: This was a randomized, placebo- and positive-controlled, double-dummy, double-blind, four-way crossover study, in which healthy subjects (n = 85) were randomized to 7 days of once-daily treatment of FF/VI (200/25 or 800/100 µg) or placebo or single-dose oral moxifloxacin (single-blind, 400 mg). In the supportive TQT study, subjects (n = 40) were randomized to single-dose inhaled FF (4000 µg), oral moxifloxacin (400 mg) or placebo. RESULTS: There was a lack of effect of FF/VI (200/25 µg) on QTcF (Fridericia's correction); all time-matched mean differences from baseline relative to placebo (0-24 h) were <5 ms, with upper 90% confidence intervals (CI) of <10 ms. At 800/100 µg, FF/VI had no significant clinical effect on QTcF except at 30 min postdose when the 90% CI was >10 ms [mean (90% CI), 9.6 ms (7.2, 12.0)]. No effect on QTci (individually corrected) was observed at either strength of FF/VI, with mean time-matched treatment differences <5 ms at all time points [upper 90% CIs <10 ms (0-24 h)]. Assay sensitivity was confirmed; moxifloxacin prolonged QTcF and QTci, with time-matched mean differences from baseline relative to placebo of >10 ms (1-8 h postdose). CONCLUSIONS: Repeat once-daily dosing of FF/VI (200/25 µg), which is the highest therapeutic strength used in phase III studies, is not associated with QTc prolongation in healthy subjects. Supratherapeutic strength FF/VI (800/100 µg) demonstrated a small transient effect on QTcF but not on QTci.

[Pharmacokinetics of gastrodin from Tiangou Jiangya capsule in rats].

The paper aims to study the pharmacokinetic parameters of gastrodin in rats effected by compound compatibilitiy and different doses of Tiangou Jiangya capsule. The extracts from Gastrodiae Rhizoma( equivalent to gastrodin 16.82 mg x kg(-1) and Tiangou jiangya capsule (equivalent to gastrodin 8.410, 16.82, 33.64 mg x kg(-1)) were oral administrated to rats respectively. The plasma were taken at various time points and treated with acetonitrile to measure the contents of gastrodin by HPLC method. The mean plasma concentration-time data were analyzed by 3P97 pharmacokinetic software and the pharmacokinetic parameters between groups were treated by SPSS 16.0. The results showed that gastrodin in rat was fitted to one-compartment model, Cmax and AUC of Tiangou Jiangya capsule were in direct proportion to oral administration, and t1/2Ka had nothing to do with doses, which indicated that gastrodin was fitted first-order rate transfter process in vivo. Morever, comparison with the Gastrodiae Rhizoma extract, isodose gastrodin in Tiangou Jiangya capsule showed a significant decrease for Cmax, Ke and increase for t1/2Ke, V/Fc, this indicated that compound compatibility can delay the absorbtion of gastrodin, prolong the resident time and promote the distribution in vivo, but its bioavailability is not significantly effected.

Metabolism and disposition of vilanterol, a long-acting ß(2)-adrenoceptor agonist for inhalation use in humans.

The metabolism and disposition of vilanterol, a novel long-acting ß(2)-adrenoceptor agonist (LABA) for inhalation use, was investigated after oral administration in humans. Single oral administrations of up to 500 µg of vilanterol were shown to be safe and well tolerated in two clinical studies in healthy men. In a human radiolabel study, six healthy men received a single oral dose of 200 µg of [(14)C]vilanterol (74 kBq). Plasma, urine, and feces were collected up to 168 hours after the dose and were analyzed for vilanterol, metabolites, and radioactivity. At least 50% of the radioactive dose was orally absorbed. The primary route of excretion of drug-related material was via O-dealkylation to metabolites, which were mainly excreted in urine. Vilanterol represented a very small percentage (<0.5%) of the total drug-related material in plasma, indicative of extensive first-pass metabolism. Circulating metabolites resulted mainly from O-dealkylation and exhibited negligible pharmacologic activity. The therapeutic dose level for vilanterol is 25 µg by the inhalation route. At this low-dose level, the likelihood of pharmacologically inactive metabolites causing unexpected toxicity is negligible. In addition to providing an assessment of the disposition of vilanterol in human, this work highlights a number of complexities associated with determining human absorption, distribution, metabolism, and excretion (ADME) for inhaled molecules--mainly related to the low chemical doses and complications associated with the inhalation route of administration.

The effect of ketoconazole on the pharmacokinetics and pharmacodynamics of inhaled fluticasone furoate and vilanterol trifenatate in healthy subjects.

AIM: To investigate the effects of the cytochrome P450 3A4 (CYP3A4) inhibitor ketoconazole on the pharmacokinetics (PK) and pharmacodynamics of fluticasone furoate (FF) and vilanterol trifenatate (VI). METHODS: Two double-blind, randomized, placebo-controlled, two-way crossover studies in healthy subjects. In study 1, subjects received single doses of ketoconazole (400 mg) or placebo on days 1-6, with a single dose of inhaled VI (25 µg) on day 5. Pharmacodynamic and PK data were obtained up to 48 h following the VI dose. In study 2, subjects received once daily ketoconazole (400 mg) or placebo for 11 days, with FF/VI (200/25 µg) for the final 7 days. Pharmacodynamic and PK data were obtained up to 48 h following the day 11 dose. RESULTS: In study 1, there was no effect of co-administration of ketoconazole and VI on pharmacodynamic or PK parameters. In study 2, co-administration of ketoconazole and FF/VI had no effect on 0-4 h maximal heart rate or minimal blood potassium {treatment difference [90% confidence interval (CI)] -0.6 beats min(-1) (-5.8, 4.5) and 0.04 mmol l(-1) (-0.03, 0.11), respectively}, whilst there was a 27% decrease in 24 h weighted mean serum cortisol [treatment ratio (90% CI) 0.73 (0.62, 0.86)]. Co-administration of ketoconazole increased [percentage change (90% CI)] FF area under the curve (0-24) and maximal plasma concentration by 36% (16, 59) and 33% (12, 58), respectively, and VI area under the curve (0-t') and maximal plasma concentration by 65% (38, 97) and 22% (8, 38), respectively. CONCLUSION: Co-administration of FF/VI or VI with ketoconazole resulted in a less than twofold increase in systemic exposure to FF and VI. There was no increase in ß-agonist systemic pharmacodynamic effects, while serum cortisol was decreased by 27%. Co-administration of FF/VI with strong CYP3A4 inhibitors has the potential to increase systemic exposure to both fluticasone furoate and vilanterol, which could lead to an increase in the potential for adverse reactions.

The safety, pharmacokinetics and pharmacodynamics of a combination of fluticasone furoate and vilanterol in healthy Japanese subjects.

OBJECTIVE: To evaluate the safety, pharmacokinetics and pharmacodynamics of fluticasone furoate (FF) and vilanterol (VI) administered alone or in combination in three Phase I studies in healthy Japanese male subjects. MATERIALS: FF, VI and FF/VI inhalation powder in a novel dry powder inhaler (nDPI). METHODS: Study A: 48 subjects received the first dose on Day 1, followed by a 4-day washout and once-daily (OD) repeat doses of FF 200, 400 or 800 µg or placebo from Day 5 to Day 11 (7 days). Study B: 32 subjects received repeat doses of VI (12.5, 25 µg) OD for 7 days. Study C: 16 subjects received single doses of FF (800 µg), VI (50 µg), FF/VI (800/50 µg) and placebo. RESULTS: Overall, there were no safety concerns and no major differences were found in treatment-related adverse events when FF and VI were administered alone or in combination. Peak plasma concentration of FF and VI following repeat dosing was up to two times higher compared with the single dose. Individual pharmacokinetic parameters of FF and VI differed when co-administered but the differences from monotherapy were not clinically significant. Repeat dosing of FF affected weighted mean (0 - 24 hours) serum cortisol with FF 200, 400 and 800 µg resulting in respective reductions from placebo of 32%, 38% and 97%, respectively. Mean maximum heart rate (0 - 4 hours) was comparable between placebo, VI 12.5 and 25 µg over 7 days of dosing; for single dosing of FF/VI 800/50 and VI 50 µg, heart rate was comparable (70 and 73 bpm, respectively) and this was higher than FF 800 µg (66 bpm) or placebo (64 bpm), but the difference was not clinically significant. CONCLUSIONS: In healthy Japanese subjects, no safety concerns were found following repeat dosing of FF and VI or single dosing of FF, VI and FF/VI. Systemic exposure to FF and VI increased in a dose-dependent manner. Serum cortisol level was suppressed by 97% after 7 days repeat administration of FF at a dose of 800 µg. Heart rate with a single dose of VI 50 µg was higher than that of placebo, though not to a clinically significant extent.

[Study on effect of combined application on distribution of gastrodigenin in rats].

To determine the concentration of gastrodigenin in tissue homogenates with high performance liquid chromatography (HPLC) , in order to study the changes of the distribution of gastrodigenin before and after combined application in rat tissues, including heart, liver, spleen, lung, kidney and brain tissues. The study showed that gastrodigenin could be found in kidney, liver, heart, lungs, spleen and brain tissues. After the combined application of Gastrodiae Rhizoma and Ligustici Wallichii Rhizoma, the content of gastrodigenin decreased in kidney and liver to varying degrees, while increasing in lung and brain. This indicated that Ligustici Wallichii Rhizoma had certain impact on the in vivo distribution of gastrodigenin, an active ingredient in Gastrodiae Rhizoma, because it could improve gastrodigenin's distribution in lung and brain tissues. The study provides scientific basis for the combined application of Gastrodiae Rhizoma and Ligustici Wallichii Rhizoma in treating brain diseases.

Urine concentrations of vilanterol and its metabolites, GSK932009 and GW630200, after inhalation of therapeutic and supratherapeutic doses.

The 2023 Prohibited List issued by the World Anti-Doping Agency (WADA) permits athletes to inhale the beta2 -agonist vilanterol at a standard dose of 25 µg daily. However, given limited data on urine pharmacokinetics, vilanterol has no urinary threshold or decision limit to discriminate therapeutic from supratherapeutic use. We investigated urine concentrations of vilanterol and its main metabolites GSK932009 and GW630200 over 0-72 h following inhalation of therapeutic (25 µg) or supratherapeutic (100 µg) doses and repeat-dose administration for 7 days of 25 or 100 µg·day-1 in 25 trained men and women. Vilanterol administration was followed by 1 h of exercise. GW630200 urine concentrations were low and insufficient for threshold purposes, and while GSK932009 had higher urine concentrations, it could not discriminate between therapeutic and supratherapeutic use. Mean (range) maximum urine concentrations of parent vilanterol were 1.2 (0.2-4.1) and 6.2 (1.4-14.3) ng·ml-1 for single-dose 25 and 100 µg vilanterol, respectively, and 2.0 (0.3-4.8) and 22.4 (6.4-42.1) ng·ml-1 for repeat-dose 25 and 100 µg·day-1 vilanterol. In 333 samples collected 6 h post-administration and considering WADA TD2022DL, a 3.1 ng·ml-1 vilanterol cut-off showed 30% sensitivity in detecting supratherapeutic use at 100 µg versus therapeutic use at 25 µg. Considering inter- and intra-individual variability and guard bands in doping analysis, a 6 ng·ml-1 decision limit, which could be shifted upwards in samples with specific gravity >1.018, appears sufficiently high to minimize risk of samples exceeding the decision limit after therapeutic use of vilanterol, while demonstrating the ability to detect supratherapeutic use at 100 µg.

[Intestinal absorption characteristics of gastrodigenin in rats].

OBJECTIVE: To investigate the intestinal absorption characteristics of gastrodigenin. METHOD: In vitro everted gut sac model and in situ rat single-pass intestinal perfusion model were used to evaluate the absorption characteristics of gastrodigenin in the different intestinal segments. The concentrations of gastrodigenin in the samples were determined by Ultra Performance Liquid Chromatography (UPLC) method, and the relevant absorption parameters were calculated. RESULT: In the everted gut sac tests, no significant difference of absorption among the four segments was observed. A positive correlation was found between drug concentration and the accumulated absorption amount (Q). At the concentration of 400 mg x L(-1), the Q of gastrodigenin in the duodenum, jejunum, ileum and colon were 224.33, 225.81, 233.18 and 189.25 microg, respectively. The in situ rat single-pass intestinal perfusion tests showed that there was also no significant difference of absorption among the four segments. The absorption rates (A) of gastrodigenin in the duodenum, jejunum, ileum and colon were 45.8%, 48.39%, 47.00%, 54.35%, respectively. CONCLUSION: Gastrodigenin can be well absorbed via passive diffusion in the intestine. The absorption rates of gastrodigenin in the different intestinal segments show no regioselectivity.