Distribution Of Active Components Research Articles

In vivo distribution and pharmacokinetics of multiple active components from Danshen and Sanqi and their combination via inner ear administration

Ethnopharmacological relevanceSalvia miltiorrhiza Bunge (Labiatae sp. plant, Chinese name Danshen) and Panax notoginseng (Burk.) F. H. Chen (Araliaceae plant, Chinese name Sanqi) have a long history in treating coronary heart disease, cerebrovascular disease and inner ear disorders in traditional Chinese medicine. To provide a rational basis for the use of these herbs in clinical practice, we investigated the in vivo distribution and pharmacokinetics of marker agents in Danshen and Sanqi via intravenous and inner ear administration and explored the potential interactions of these agents in compound prescription. Materials and methodsGuinea pigs were given Danshen extracts (salvianolic acid B, tanshinone IIA), Sanqi extracts (Panax notoginseng saponins) and combination of the two extracts via intravenous and intratympanic administration (IT). Samples from the brain, inner ear perilymph (PL), cerebrospinal fluid (CSF) and plasma were collected at different time points. The concentration of salvianolic acid B (Sal B), tanshinone IIA (Ts IIA), notoginsenoside R1 (R1), ginsenoside Rg1 (Rg1) and ginsenoside Rb1 (Rb1) was determined by high-performance liquid chromatography coupled with a diode array detector (DAD). Pharmacokinetic parameters were estimated using non-compartmental methods. ResultsLocal drug application via inner ear greatly improved drug distribution within the PL, CSF and brain tissues compared with intravenous administration (IV). The values of Cmax and AUC(0–t) after IT were significantly higher than IV. In comparison with IT of Danshen and Sanqi alone, the pharmacokinetic parameters for R1, Rg1, Rb1, Sal B and Ts IIA were markedly different in the compound prescription. The compound compatibility enhanced the transport of Danshen components into the brain through the inner ear and apparently prolonged the retention time in CSF while decreasing the distribution of Sanqi components in the inner ear and brain. ConclusionsThe results indicated that local drug application to the inner ear was a more effective delivery route than systemic administration. Co-administration of Danshen and Sanqi could cause significant pharmacokinetic herb–herb interactions in guinea pigs. The multiple active components via inner ear administration might be promising candidates for the treatment of inner ear and brain diseases.

Si-SiOx-Cristobalite/Graphite Composite as Anode for Li-ion Batteries

A gentle route is developed to fabricate multicomponent nanosilicon-based composite by using SiO, NaOH and graphite as starting materials. The composite is composed of nanosilicon, nonstoichiometric SiOx, cristobalite and graphite (Labeled as Si-SiOx-cristobalite/graphite). Used as anode material in Li-ion batteries, the Si-SiOx-cristobalite/graphite exhibits high lithium storage capacity with good cycling stability and rate capability. At a current density of 100mAg−1, the composite shows a stable reversible capacity of about 990 mAh g−1(Calculated on the total mass of the composite) and the capacity retention is nearly 100% after 150 cycles. Even at 1600mAg−1, the stable discharge capacity of the composite is also over than the theoretic capacity of graphite. In the composite, cristobalite is inert to lithium, while the other components are involved in lithiation process during the first discharge. The excellent electrochemical performance of the Si-SiOx-cristobalite/graphite electrode is attributed to the uniform distribution of active components in inert media and the conductivity enhanced by graphite.

Solar light induced rhodamine B degradation assisted by TiO2–Zn–Al LDH based photocatalysts

A series of TiO2/Zn–Al layered double hydroxides (LDHs) based composites were synthesized and their photocatalytic efficiency in rhodamine B photodegradation reaction under solar light irradiation was tested. The aim of this study was to develop photocatalysts based on TiO2/Zn–Al layered double hydroxides that can be activated by solar light irradiation. The influence of TiO2 doping (1, 2 and 3mass%) on the photocatalytic properties of developed TiO2/Zn–Al LDHs nanocomposites was studied. Different photocatalytic behaviour of composites was interpreted in correlation to their structural, textural, morphological properties and kinetic parameters. All nanocomposites were active in the selected reaction. It was observed that the presence of Zn2TiO4 coupled with the ZnO phase contributes to the activity provoked by solar light irradiation. The photodegradation follows the pseudo first-order kinetics in accordance with the Langmuir–Hinshelwood model. The kinetic study suggested that the applied synthesis methodology resulted in homogeneous distribution of TiO2 and other active components on the photocatalyst surface leading to better accessibility of active sites. The developed synthesis method enables favourable interactions among active phases. Novel TiO2/LDH based photocatalysts are advantageous considering the low-cost and simple preparation, ensuring high photodegradation efficiency, making them appealing for the application in the field of water treatment.

Ambient Mass Spectrometry Imaging: Plasma Assisted Laser Desorption Ionization Mass Spectrometry Imaging and Its Applications

Mass spectrometry imaging (MSI) has been widely used in many research areas for the advantages of providing informative molecular distribution with high specificity. Among the recent progress, ambient MSI has attracted increasing interests owing to its characteristics of ambient, in situ, and nonpretreatment analysis. Here, we are presenting the ambient MSI for traditional Chinese medicines (TCMs) and authentication of work of art and documents using plasma assisted laser desorption ionization mass spectrometry (PALDI-MS). Compared with current ambient MSI methods, an excellent average resolution of 60 μm × 60 μm pixel size was achieved using this system. The feasibility of PALDI-based MSI was confirmed by seal imaging, and its authentication applications were demonstrated by imaging of printed Chinese characters. Imaging of the Radix Scutellariae slice showed that the two active components, baicalein and wogonin, mainly were distributed in the epidermis of the root, which proposed an approach for distinguishing TCMs' origins and the distribution of active components of TCMs and exploring the environmental effects of plant growth. PALDI-MS imaging provides a strong complement for the MSI strategy with the enhanced spatial resolution, which is promising in many research fields, such as artwork identification, TCMs' and botanic research, pharmaceutical applications, etc.

Foster®: A High-Efficiency Combination Metered Dose Inhaler with Consistent Particle Size Distribution at Alternative Flow Rates

This publication adds perspective to a recent publication by Johal et al. that presented the performance of combination inhalation therapies at a flow rate differing from that recommended by the regulatory authorities for metered dose inhaler (MDI) performance testing. Altering the flow rate through an impactor can create potential pitfalls which can result in performance misrepresentation. In-house data for Foster® (Chiesi, Parma, Italy) and Flutiform® (Bard Pharmaceuticals Limited, Cambridge, UK) have been collected using standard pharmacopaeial conditions and also at the unconventional 60 L/min flow rate utilized by Johal et al. A marked reduction in mass median aerodynamic diameters (MMADs) of both the inhaled corticosteroids (ICS) and long-acting beta agonists in Foster MDI from approximately 1.2–0.5 μm with increase in flow rate (Johal et al.) is not observed. Use of the Andersen cascade impactor at flow rates above 28.3 L/min is not common practice. The industry generally utilizes data from the next generation impactor (NGI), an impactor specifically designed and developed for this purpose. Data for the ICS component of Foster have been generated using an NGI operated at 30 and 60 L/min, yielding an MMAD (±SD) of 1.1 ± 0.1 μm at both flow rates. Johal et al. suggest that submicron particles are prone to be exhaled by the patient, and therefore imply that they may be non-effective. However, therapeutic significance of submicron particles is supported by a scintigraphic lung deposition study carried out using the Foster MDI. The in vivo data highlight that just 2–3% of the nominal dose was exhaled, with 31–34% deposited in the lungs. Consistent particle size distribution of both active drug components delivered from Foster MDI at flow rates of 28–30 and 60 L/min is observed.

The effect of active component distribution in a porous structure of supported catalyst

The catalytic process in supported catalyst with nonuniform distribution of active component among the pores of different size is considered. Some previous as well as new estimates are presented. The limit value of diffusivity in small pores (D L < 10−8 cm2/s) is established, at which the distribution can takes an effect. That is possible in the case of capillary condensation, when micro-pores are filled with liquid while macro-pores are filled with gas. Such diffusivity is also observed at configuration or surface diffusion in zeolite channels. Then the distribution may influence the pellet effectivity when the activity of active component inside zeolite crystals is higher than that on its external surface.

Spatial structure and geographic distribution of major active component in medical herb Dipsacus asperoides population

To study the spatial structure and geographic distribution of major active components in medical herb Dipsacus asperoides population, in Guizhou province, the author obtained the asperosaponin VI content among 38 D. asperoides population points. Using spatial statistic and traditional statistic, the spatial variation pattern has been found. Combining the environment variables, it is tried to reveal the geographic distribution rules between group of major active component in medical herb D. asperoides population and group of environmental factors. The results show: the spatial structure of major active component in medical herb D. asperoides population is randomly distributed in global space, but has two aggregation points which have a high positive correlation in local space; environmental factors value for group of major active component in medical herb D. asperoides population has a large difference in the interior-group, but environmental factors value has a small difference in inter-group.

Preparation of AlCl3/silica gel catalyst for simultaneously removing thiophene and olefins from coking benzene by inclosed grafting method

AlCl3/silica gel catalysts were prepared by inclosed grafting method in the autoclave and their catalytic activities for alkylation reaction of thiophene with olefins in benzene were studied. The gas chromatograph and chromatography–mass spectroscopy were used to quantitatively determine the thiophene in benzene and qualitatively measure the reaction products, respectively. XPS, SEM, EDX and N2 adsorption techniques were used to characterize the physical and chemical properties of catalyst samples. The results show that AlCl3 can be effectively anchored by reacting with the silanol groups on silica gel surface to form the Six(OH)y−aOaAlCl(3−a) species and the prepared AlCl3/silica gel catalyst possesses the significant activity for the alkylation reaction of thiophene and olefin. The preparation conditions, such as mass ratio of AlCl3/silica gel support, grafting temperature and time, and thermal treatment temperature of silica gel, have an important role on the content and distribution of active component over silica gel support, and thus affect the catalytic activity. The optimum preparation conditions of AlCl3/silica gel catalyst are that AlCl3 is grafted on silica gel support, which has been thermally treated at 400°C for 3h, and at 180°C for 4h with the mass ratio of 0.20 for AlCl3/silica gel support. The loading ratio of AlCl3 on silica gel can reach about 64wt.% and the optimal conversion rate of thiophene in benzene is 94.23% when the ratio of liquid to catalyst is 20mL/g.

K2CO3/Al2O3 for Capturing CO2 in Flue Gas from Power Plants. Part 3: CO2 Capture Behaviors of K2CO3/Al2O3 in a Bubbling Fluidized-Bed Reactor

K2CO3/Al2O3 used for capturing CO2 in flue gas is thoroughly investigated. The present paper focuses on the CO2 capture behaviors of K2CO3/Al2O3 in a bubbling fluidized-bed reactor. It is found that K2CO3/Al2O3 shows a higher CO2 capture capacity than other potassium-based sorbents. The carbonation reaction capacities are in the range of 290–319 mg of CO2/g of K2CO3 for K2CO3/Al2O3 with loading amounts of 12.8–36.8%. It is abruptly decreased to 148.98 mg of CO2/g of K2CO3 when the loading amount of K2CO3 increases to 45.1%. The reason is attributed to the change of the active component distribution behavior. The total CO2 sorption capacity maintains a high level when the carbonation temperature is in the range of 60–80 °C. The CO2 capture behavior is significantly affected by the changing H2O concentration and the process of water pretreatment for the sorbent. The effect of the CO2 concentration is not significant on the carbonation conversion when it is in the range of 10–30%. The sorbent is completely r...

Herb-drug interactions: Focus on metabolic enzymes and transporters

As the uses of herbal medicines from traditional natural products are increased, the need for pharmacokinetic studies and relevant data are also increased for safe pharmacotherapy. The market entry for the traditional herbal medicine is easier compared with that for synthetic drugs because of a lower regulatory barrier. Thus, the exact mechanisms for the absorption, distribution, metabolism and excretion of active components in herbal medicines and the potential herb-drug interactions are not always fully understood. Recently, there has been an increasing interest in pharmacokinetic studies of herbal remedies and relevant data of commonly used herbal remedies are accumulating in this field. In this review, the effects of nine botanicals (ginkgo, green tea, grapes, licorice, saw palmetto, garlic milk thistle, ginseng and St. John's wort) on metabolic enzymes and transporters affecting absorption and disposition of herbal products are summarized. The source of samples (extracts and individual components), the species (human and animal) and in vivo and in vitro systems were separately reviewed for a better understanding of herb-drug interactions.

A Pd–Fe/α-Al 2O 3/cordierite monolithic catalyst for CO coupling to oxalate

A novel Pd–Fe/α-Al 2O 3/cordierite monolithic catalyst was prepared for the synthesis of diethyl oxalate from CO and ethyl nitrite. The palladium-based monolithic catalyst with an optimal thickness (15 μm) of Al 2O 3 washcoat showed excellent catalytic activity and selectivity in a continuous flow, fixed-bed microreactor. The physicochemical properties of catalyst were studied by a variety of characterization techniques. Catalytic performances of Pd–Fe/α-Al 2O 3/cordierite monolithic catalysts were dependent on particle size of alumina-sol, thickness of Al 2O 3 washcoat, pore structure, surface acidity of carrier, and distribution of active metal component on the Al 2O 3 washcoat. Under the mild reaction conditions, CO conversion was 32% and the space–time yield of diethyl oxalate was 429 g/(L h). Pd efficiency (DEO(g)/Pd(g)/h) of the monolithic catalyst (274 h −1) was much higher than that of a reference pellet catalyst (46 h −1), probably due to high dispersion of the Pd nanoparticles on the surface of the monolithic catalyst.

Effect of surface properties of activated carbon on CO oxidation over supported Wacker-type catalysts

The effects of chemical pretreatments of the support on CO oxidation over the activated carbon-supported Wacker-type catalyst were studied. Dry oxidation by air at 400 °C and wet oxidation in H 2O 2 and H 3PO 4 aqueous solution were used to modify the physical and chemical properties of activated carbon. The textural and surface characteristics of activated carbons were characterized by nitrogen adsorption, temperature-programmed desorption (TPD) and Boehm titration. The dispersion of active phase and chemical environment of CO oxidation catalysts were investigated by X-ray Photoelectron Spectroscopy (XPS) and temperature-programmed reduction (TPR). CO oxidation results showed that the catalyst prepared using activated carbon with high mesopores and oxygen-functional groups as support performs higher CO oxidation activity at ambient temperature, especially in high relative humidity. XPS and TPR results show that the activated carbon support with enriched oxygen-functional groups would benefit the distribution of active components (Pd 2+, Cu 2+) on the catalyst surface and the formation of easily reducible Cu 2+ species.

Evaluation of API-Distribution and Coating Thickness by NIR Spectroscopy and Raman Chemical Mapping

Spray coating is an important unit operation in the pharmaceutical industry. The ultimate goal is to produce uniformly coated products with the desired amount of coating material, to guarantee controlled active pharmaceutical ingredient (API) release. The coating thickness and homogeneity can be determined with spectroscopic process analytical technology (PAT) tools, like near-infrared (NIR) and Raman spectroscopy. Here, both spectroscopic techniques were applied for the analysis and characterization of tablet coatings. Due to the relatively small coating thickness with respect to the penetration depth of the excitation, both laser light and Raman scattering penetrate through the coated layer. Hence, Raman chemical mapping can also be used to analyse qualitatively the chemical composition (i. e. the distribution of (active) components) in tablets. A quantitative multivariate data analysis (MVDA) based model for the tablet coating thickness was developed on basis of tablets sampled from different stages of a coating process [1, 2]. Calibration was carried out by monitoring weight gain, which is also used in industrial quality control. A comparison between calibration models for four different sampling modes (Mapping, Line, Super Macro and Single Point) was performed. The root mean squared error of prediction (RMSEP) of the different sampling methods showed 1.25, 1.33, 2.1 and 2.05 mg for Mapping, Line, Super Macro and Single Point measurement respectively. In accordance, NIR measurements with a fiber optical reflectance probe showed a RMSEP of 1.07 mg, representing a good correlation between the two methods. Although the RMSEP of the mapping mode is the smallest, it does not compensate for the much longer measurement time. Raman chemical mapping is conditionally applicable for the determination of coating thickness, but it is not a rapid standard method.

Research on target depth classification in low frequency acoustic field of shallow water

The cross-spectrum characteristics of sound pressure between two hydrophones deployed vertically are analyzed in low frequency acoustic field of shallow water, more attentions are paid to the cross-spectrum active component of sound pressure when only two normal modes are trapped in the waveguide. The numerical results show that （1） the sign of the sound pressure cross-spectrum active component is independent of range when receiving transducers placed in appropriate depths, so it can be used to tell whether the sound source is near the surface or underwater by selecting a pair of appropriate deploying depth of transducers; （2） acoustic velocity profiles have little effects on the application of this method, the seabed attenuation will limit the detection range, but the algorithm still has a good robustness in the valid detection range. Approximate theoretic analysis of cross-spectrum active component characteristics is proposed in the paper combined with the concept of effective depth, and the prediction formula of appropriate deploying depth of transducers is presented. The theoretic analysis indicates that the sum of the bi-hydrophone depths should be equal to the waveguide effective depth and the sign distribution of the sound pressure cross-spectrum active component is divided into three level regions in an ideal pressure-release waveguide. The theoretic analysis provides deeper understanding of the low-frequency sound field characteristics in shallow water and also guidance to the application of the algorithm.

The Influence of Thermal Treatment and Noble Metal Addition on Hopcalite Activity in Oxidation of Thiophene

In this paper the comparison of activity of hopcalite (Mn–Cu mixed oxides) modified with noble metals (Pd, Pt and Au) calcined at 300, 400 and 500 °C in oxidation of thiophene was presented. Hopcalite modified with Pd demonstrated the highest activity among the studied samples, thus the results of a more detailed study of the most promising palladium catalyst were also shown. Surface and bulk properties of catalyst were studied with BET, XRD, TPRH2 and TG-DTA-MS. The redox properties and distribution of active components on the catalyst surface seem to be important factors influencing the modified hopcalite performance in the oxidation reactions. It was found that irreversible changes occurred during thermal treatment in the Pd-modified hopcalite structure, however they have no marked influence on activity of modified catalysts.

Surface Selective Deposition of Mo(IV) on Ni/TiO2 Particles in Aqueous Solutions

The selective depositions of MoS2 and MoO2 over Ni surfaces are demonstrated on Ni/TiO2 particles in a mild electroless deposition process. High-resolution transmission electron microscopy (HRTEM) images show the uniform distribution of 10-30 nm spherical and hemispherical Ni particles on TiO2 surface, and three to six layers of MoS2 on the surface of Ni particles. The as-prepared MoS2-Ni/TiO2 is used as a catalyst for the hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT), and shows a significant increase over commercial catalysts in turnover frequencies as the result of unique distribution of active components in the binary catalyst. The selective material deposition is explained in the context of Ni catalyzed KBH4 decomposition, which produces strong reducing species responsible for the site selective deposition of Mo. The synthetic method can be potentially used to prepare bimetallic materials with similar nanostructures such as those of Mo-Co, Mo-Pd, and Mo-Rh.

Characteristics of drying and active component distribution in alumina monoliths using 1H-NMR imaging

The distribution of water in the impregnated monolithic substrates was visualized by 1H-NMR imaging. The two-dimensional water content maps along the axial and radial directions have been collected for different monoliths at variation of the drying conditions. Using the blow-through air for drying of the substrate with coated external walls and with free access of air to external walls leads to the parabolic profile of water concentration along the axial direction of the sample. Drying of the monoliths with open external walls proceeds more uniformly in the radial and axial directions of the substrate. Characteristics of drying of alumina monoliths, calcined at 600, 900 and 1200 °C having differences in the pore structure and pore distribution, are studied. During drying of the impregnated washcoated monolith the certain part of the introduced active component precursor (H 2PtCl 6 or H 2PdCl 4) is transported from the substrate macropores to the mesoporous washcoated layer which leads to enrichment of the washcoat of the final catalyst by active component. The non-destructive character of 1H-NMR microimaging demonstrated its capability to visualize the water content maps in monoliths in the presence of Pt and Pd.

Optimization of the active component distribution through the catalyst bed for the case of adiabatic reactor

This article is the next one in the previous series of publications concerning the optimal active component distribution. The aim of the present work is to extend the optimization problem taking into account the energy balance. The variational problem on searching for the optimal active component distribution profile along the catalyst bed was formulated for the case of an adiabatic reactor at an arbitrary form of reaction rate expression. The Euler differential equation was derived and the existence conditions for the solution of variational problem were obtained. A numerical algorithm was suggested and the optimal profiles of the active component distribution were calculated for the first-order reaction. Under isothermal conditions with linear dependence of the reaction rate on reactant concentration at a constant mass transfer coefficient, the uniform distribution is optimal. As opposed to the case of an isothermal reactor with a first-order catalytic reaction, in an adiabatic reactor considerable economy in the active component loading might be achieved due to optimization of its distribution. It was shown that the optimal active component distribution profiles were axially decreasing for the first-order exothermic reactions and increasing for endothermic reactions. The optimal active component distribution profile was calculated for the case of methane combustion on catalytic monoliths.

Improvement of the catalytic monoliths efficiency for CO oxidation using non-uniform active component distribution along the monolith length

It is shown that the efficiency of catalytic packages can be improved using two approaches. The monotone increase of the active component concentration towards the monolith outlet is shown optimal for minimization of the total active component loading at the preserved purification degree. To resolve the problem of achieving the maximal purification degree at a fixed quantity of the active component, it is preferable to concentrate the active component near the duct entrance.

Optimization of the active component distribution through the catalyst bed

A variational problem was formulated to determine the optimal axially non-uniform catalyst activity distribution along the fixed catalyst bed. It was observed that the mass transport limitations or non-isothermal temperature profile are necessary conditions for potential optimization of the catalyst distribution along the bed length. Under isothermal conditions with linear dependence of the reaction rate on concentration at a constant mass transfer coefficient, the uniform distribution is optimal. Analytical solution for the first-order reaction and numerical solutions for power-law kinetics were found.