Determination of scopolamine, atropine and anisodamine in Flos daturae by capillary electrophoresis.

A capillary electrophoresis method was developed for the separation and determination of tropane alkaloids in Flos daturae plants. Separation was performed on a fused silica capillary(42.1 cm x 50 microm i.d.) at an applied voltage of 20 kV. Scopolamine, atropine and anisodamine were well separated in the buffer of 50 mmol/L phosphate buffer (pH 5.0) containing 20% (v/v) tetrahydrofuran (THF). Beer's law was obeyed in the range of concentration of 2.4-21.8 microg/mL for scopolamine, 4.0-36.0 microg/mL for atropine and 2.6-23.7 microg/mL for anisodamine, respectively, and the correlation coefficients were over 0.999 (n = 6). The developed method was applied for the analysis of herb samples.     

Simultaneous determination of physostigmine and tetrahydroaminoacridine in a transdermal permeation study by high-performance liquid chromatography

A selective and stability-indicating high-performance liquid chromatographic assay with diazepam as the internal standard was developed for simultaneously analyzing physostigmine and tetrahydroaminoacridine in skin samples, permeation diffusates and dosage form. Baseline resolution was achieved with an octadecyl column for physostigmine, its two degradation products and tetrahydroaminoacridine. Peak homogeneity of physostigmine and tetrahydroaminoacridine was confirmed. The calibration curves for both drugs in skin samples were established at 1-50 micrograms per 200 mg skin. Those for diffusate samples were at 10-50 ng per 50 microliters for physostigmine and 30-150 ng per 50 microliters for tetrahydroaminoacridine. The assay was reproducible with within-day and between-day variations of 5-6 and 4-10%, respectively. Application of the assay for in vitro transdermal permeation study was demonstrated.     

Development of a microwave-assisted extraction of atropine and scopolamine from Solanaceae family plants followed by a QuEChERS cleanup procedure

In this work, a novel method based on the microwave-assisted extraction (MAE), the QuEChERS dispersive solid-phase extraction and gas chromatography–mass spectrometry was developed for the determination of atropine and scopolamine in plant samples from Datura and Brugmansia genera, which belong to the Solanaceae family. The experimental conditions for MAE, such as temperature, time of extraction, and volume of the extracting solvent as well as extract purification procedure parameters were optimized by the Doehlert uniform shell design and the response surface methodology. For quantitative analysis and validation, a standard addition calibration method was used to reduce the matrix effect. The limits of detection from 3.0 to 3.4 µg g^?1 of dry matter and the linearity of the calibration dependence were suitable for the analysis of plant extracts. The repeatability and intermediate precision for both analytes were found to be acceptable (<15%). The developed method was successfully applied to the samples of leaves and seeds of Datura and Brugmansia.     

Preparative separation of atropine and scopolamine from Daturae metelis Flos using pH-zone-refining counter-current chromatography with counter-rotation and dual-mode elution procedure

To isolate atropine and scopolamine from Daturae metelis Flos, three different elution modes have been applied in pH-zone-refining counter-current chromatography. These separations were performed with a two-phase solvent system composed of ethyl acetate/n-butanol/water (4:1:5 v/v) with 0.50% triethylamine in the organic phase and 0.15% hydrochloric acid in the aqueous phase. As a result, the best separation was obtained by counter-rotation and dual-mode elution procedure. In this new separation mode, the mobile phase and stationary phase were exchanged when the rotation direction was reversed. The two purified alkaloids (purity over 98% as determined by HPLC) were identified by ESI-MS, (1)H-NMR and (13)C-NMR.     

Simultaneous determination of atropine,scopolamine, and anisodamine in Flos daturae by capillary electrophoresis using a capillary coated by graphene oxide

A novel CE method was developed for the separation and determination of three main tropane alkaloids in Flos daturae with a capillary coated by graphene oxide (GO). The GO‐coated capillary was characterized by SEM, energy dispersive X‐ray spectroscopy, and Raman spectroscopy, and the results indicated that the inner surface of the capillary was partially coated by GO. A phosphate solution (40 mM, pH7.0) containing 20% v/v methanol and 30% v/v acetonitrile was used as the running buffer for the analysis of the atropine, scopolamine, and anisodamine. The linear ranges of atropine, scopolamine, and anisodamine was 0.5–200 μg/mL with satisfactory correlation coefficients (R²) > 0.9987, and this novel method provided an efficient separation for three tropane alkaloids as well as a good reproducibility and stability. Finally, the method was successfully applied for the determination of these three tropane alkaloids in plant extracts.     

Simultaneous determination of atropine,anisodamine, and scopolamine in plant extract by nonaqueous capillary electrophoresis coupled with electrochemiluminescence and electrochemistry dual detection

A rapid and simple method was demonstrated for the analysis of atropine, anisodamine, and scopolamine by nonaqueous capillary electrophoresis (NACE) coupled with electrochemiluminescence (ECL) and electrochemistry (EC) dual detection. The mixture of acetonitrile (ACN) and 2-propanol containing 1 M acetic acid (HAc), 20 mM sodium acetate (NaAc), and 2.5 mM tetrabutylammonium perchlorate (TBAP) was used as the electrophoretic buffer. Although a short capillary of 18 cm was used, the decoupler was not needed and the separation efficiency was good. The linear ranges of atropine, anisodamine, and scopolamine were 0.5–50, 5–2000, and 50–2000 μM, respectively. For six replicate measurements of 100 μM scopolamine, 15 μM atropine, and 200 μM anisodamine, the RSDs of ECL intensity, EC current, and migration time were less than 3.6%, 4.5%, and 0.3%, respectively. In addition, because the organic buffer was used, the working electrode (Pt) was not easily fouled and did not need reactivation. The method was also applied for the determination of these three alkaloids in Flos daturae extract.     

The effects of transdermal permeation enhancers on thermotropic phase behaviour of a stratum corneum lipid model

This study evaluates the interactions of a model stratum corneum (SC) lipid system based on ceramide AP (N-(2-hydroxystearoyl)phytosphingosine) with three selected permeation enhancers including urea, oleic acid (OA), and N-lauroylglycine lauryl ester (12G12) using temperature-dependent small-angle X-ray diffraction measurements. As a first step, the thermotropic phase behaviour of the control SC lipid membrane, i.e. without enhancer, was characterized. The system shows two separated phases at 32 °C, which mix into another phase at around 45 °C. This phase is stable till 70 °C when the repeat distance starts to decrease. After cooling, only one phase is visible which shows two phase transitions at 45 and 70 °C again. Based on these results, the effects of the permeation enhancers were studied. The permeation enhancers influence the phase behaviour of the system. Urea and 12G12 cause a concentration-dependent shift of the phase transition temperatures while OA induces a phase separation. The results from this simple model system may provide basis for studies on more complex systems or real SC.     

微流控芯片测定丁溴东莨菪碱注射液中丁溴东莨菪碱

建立了微流控芯片非接触电导检测法测定丁溴东莨菪碱注射液中丁溴东莨菪碱含量的方法。优化选择3 mmol/LHAc+2 mmol/LNaAc(pH4.5)为缓冲溶液,1.0 mmol/Lβ-CD为添加剂,分离电压为2.00 kV,进样时间为10 s,丁溴东莨菪碱在2 min内可得到较好分离,线性范围为20～250μg/mL(r=0.998),检出限为6.0μg/mL(S/N=3),RSD为2.1%,加标回收率为97.0%～99.6%。     

Membrane permeation-controlled transdermal delivery system design. Influence of controlling membrane and adhesive on skin permeation of isosorbide dinitrate

A membrane permeation-controlled transdermal delivery system (MC-TDS) of isosorbide dinitrate (ISDN), a model drug, was prepared from polyvinyl alcohol aqueous gel containing the drug, a membrane consisting of ethylene-vinyl acetate copolymer membrane and acrylic adhesive (EV-a). The permeability of ISDN through the EV-a membrane was 2.5 times higher than that through excised hairless rat skin. The ratio of plasma concentration of ISDN after application of MC-TDS on stripped (damaged) skin relative to intact skin was lower than that after application of Frandol tape-S, a marketed ISDN TDS, which suggests that the EV-a membrane might work as a control membrane for overall delivery rate of ISDN to the body. When MC-TDS stored at 30 degrees C for 13.5-48h was applied to the damaged skin, however, the initial plasma concentration of ISDN was very much higher than the expected therapeutic level and was not controlled by the EV-a membrane. The initial high plasma concentration of ISDN after application of the stored MC-TDS on the damaged skin was due to migration of ISDN from the reservoir to the adhesive during storage at 30 degrees C. The migration of drugs into the adhesive might be an important problem in developing efficient MC-TDS.     

Evaluation of calcipotriol transdermal permeation through pig,rat and mouse skin using liquid chromatography–tandem mass spectrometry

A rapid and sensitive liquid chromatography–tandem mass spectrometric method to evaluate the permeation and retention of calcipotriol in excised samples of pig, rat and mouse skin after application of a calcipotriol ointment has been developed and validated. After sample preparation of ointment, skin homogenate and receptor medium by liquid–liquid extraction, chromatography was performed on an Extend‐C₁₈ column using isocratic elution. Detection was by electrospray ionization in the negative ion mode using multiple‐reaction monitoring of the precursor to product ion transitions of calcipotriol at m/z 411.1 → 393.5, and of lovastatin (internal standard) at m/z 403.2 → 101.2. The assay was linear in all matrices with LLOQs of 1, 0.5 and 40 ng/mL for skin homogenate, receptor medium and ointment samples respectively. In terms of the permeation profiles, it was found that calcipotriol permeated through all skins to only a limited extent over 20 h after application but was efficiently retained in all skins at a level at 20 h of between 40% (pig) and 60% (rat and mouse) of the applied dose. This indicates that calcipotriol ointment has the potential to provide sustained therapeutic benefit in the treatment of psoriasis with minimal systemic side effects. Copyright © 2013 John Wiley & Sons, Ltd.     

Radon levels assessment in some Northern Romanian salt mines

Due to their low radioactivity background, underground salt mines spaces offer a unique possibility for speleotherapy use. The knowledge of radon concentration levels in such underground environments is essential for therapeutic purposes of different respiratory and rheumatic diseases. In order to develop speleotherapy in Romania, this paper presents the results of an indoor radon concentration levels survey in some salt mines in Romania. The survey was carried out using radon monitor Pylon AB-5 system methodology validated by a CIS-P5M system. In order to investigate whether differences in depth and microclimate parameters translate into significant differences in salt mine indoor radon concentrations, have been chosen three salts mine test sites placed in the Northern part of Romania (Turda, Cacica and Ocna Dej) in stable areas of the mining field at 32?C120?m depth. Environmental microclimate conditions (mean values of air temperature 10?C14.5?°C, air humidity 65?C80%, air velocity 0.2?m/s saline aerosols and low microbial factors) have anti-bacterial, anti-microbial, and anti-inflammatory properties and recognized therapeutically effects on human body??s health. Air temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations in salt mines because temperature largely determines close spaces ventilation rates, and ventilation habits are known to have significant effects on indoor radon concentrations. The analyzed environmental conditions and recorded low levels of indoor mean radon concentration (6.9?±?0.39 and 96.5?±?4.76?Bq/m³) demonstrated the best suitability of the investigated three salt mines in Romania for speleotherapeutic applications.     

Differential permeation. Part II: Behaviors of polyvinylalocohol films in transient permeation

The variations of the permeation rate of ethanol in ethanol-water mixtures through poly(vinylalcohol) membranes of different crystallinities were studied in the transient regime. We observed an anomalous two-wave kinetics, which was accounted for in terms of a model postulating two diffusion-pathways for ethanol molecules in the polymer. One wave corresponds to the permeation of ethanol through the amorphous polymer matrix, which occurs whatever the water content in the mixture. The other wave appears only when the water content in the mixture exceeds a threshold. The higher the crystallinity, the higher the value of this threshold. This wave is attributed to the diffusion of ethanol molecules through clusters formed with the water molecules sorbed on the hydroxyl sites.     

Simultaneous determination of atropine,scopolamine, and anisodamine from Hyoscyamus niger L. in rat plasma by high‐performance liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetics study

In order to investigate the pharmacokinetics of tropane alkaloids in Hyoscyamus niger L., a sensitive and specific high‐performance liquid chromatography with tandem mass spectrometry method for the simultaneous determination of atropine, scopolamine, and anisodamine in rat plasma is developed and fully validated, using homatropine as an internal standard. The separation of the four compounds was carried out on a BDS Hypersil? C₁₈ column using a mobile phase consisting of acetonitrile and water (containing 10 mmol ammonium acetate). Calibration curves were linear from 0.2 to 40 ng/mL for atropine, scopolamine, and from 0.08 to 20 ng/mL for anisodamine. The precision of three analytes was <5.89% and the accuracy was between ?1.04 to 2.94%. This method is successfully applied to rat pharmacokinetics analysis of the three tropane alkaloids after oral administration of H. niger extract. The maximum concentration of these three tropane alkaloids was reached within 15 min, and the maximum concentrations were 31.36 ± 7.35 ng/mL for atropine, 49.94 ± 2.67 ng/mL for scopolamine, and 2.83 ± 1.49 ng/mL for anisodamine. The pharmacokinetic parameters revealed areas under the curve of 22.76 ± 5.80, 16.80 ± 3.08, and 4.31 ± 1.21 ng/h mL and mean residence times of 2.08 ± 0.55, 1.19 ± 0.45, and 3.28 ± 0.78 h for atropine, scopolamine, and anisodamine, respectively.     

Effect of the composition of lecithin/n-propanol/isopropyl myristate/water microemulsions on barrier properties of mice skin for transdermal permeation of tetracaine hydrochloride: in vitro

Effect of composition of lecithin water-in-oil and oil-in-water microemulsion on in vitro transdermal permeation of tetracaine hydrochloride was studied on mice model. The results were compared with an aqueous solution of tetracaine hydrochloride (2.7 mg/ml). In vitro skin flux and permeability coefficients were obtained using the Franz diffusion cell. Differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM) were used to study the mechanism of action of the microemulsion. Micrographs of TEM and CLSM studies were analyzed by using Image Pro Plus image software. Skin flux of tetracaine hydrochloride was found to be dependent on the composition of lecithin/n-propanol/isopropyl myristate/water microemulsions. At lower Km ratio (i.e. 0.5:1 and 0.8:1) of microemulsion, the rate of permeation of tetracaine hydrochloride was higher when compared to the microemulsion of higher Km ratio (1:1 and 1.5:1). Image analysis of TEM micrograph, 6h after application of lecithin microemulsion, showed 3.5+/-0.75-fold (p<0.001) increase in the intercellular space in the epidermis and 3.8+/-0.4-fold (p<0.001) enhancement in upper dermis. CLMS results show that sweat gland and hair follicles also provided path for permeation of the drug through the skin.     

Superposition of permeation and adsorption effects in liquid chromatography

Summary A generalized treatment of the superposition of separations based on gel-permeation chromatography (GPC) and liquid-solid chromatography (LSC) is presented. Special emphasis is given to the fact that restricted-pore entry behaviour in GPC automatically eliminates part of the surface accessible for adsorption in LSC. Therefore the simple additivity rule for K_GPC and K_ads, applied so far exclusively to adsorptive GPC interpretation, cannot be used in general and special care has to be taken if information about adsorptivities is to be deduced from the chromatographic experiment.     

The use of permeation tube device and the development of empirical formula for accurate permeation rate

A series of laboratory experiments were conducted to assess the accuracy of permeation tube (PT) devices using a calibration gas generator system to measure permeation rate (PR) of volatile organic compounds (VOCs). Calibration gas standards of benzene, toluene, and m-xylene (BTX) were produced from PTs at varying flow rates (FR) of 20-1200 mL min(-1) and constant temperature (30°C). Results indicate that changes in flow rate greatly affected the permeation rate of each VOC at this temperature. This paper presents experimental approaches to accurately measure actual permeation rate (APR) and the derivation of empirical equations for predicted permeation rate (PPR). If the magnitude of bias is defined as the difference between PPR and the manufacturer's permeation rate (MPR), the bias was typically 19-40% for toluene (T) and 31-54% for m-xylene (X). Benzene (B) exhibited the least bias of 1.4-18.8%, nevertheless our PPR values for benzene were more reliable at lower flow rates (0.75-1.20%). This study highlights the importance of flow rate and associated pressure changes as a key to accurate permeation rate estimation from permeation tube devices.     

Role of diffusion in gel permeation chromatography

A theory is developed that describes the diffusion of solute into the gel particles during a gel permeation chromatographic experiment. The particles are treated as homogeneous spheres of radius a, into which diffusion takes place with diffusion coefficient D_s. The concentration in the mobile phase at any level at any time is supposed to be uniform throughout the cross-section of the column. It is shown that in the usual columns the effect of diffusion in the mobile phase is unimportant. A determinative quantity in the process is the parameter a²/D_st, where t is the time. For large values of a²/D_st an explicit expression for concentration versus time in the mobile phase at the end of the column is derived [eq. (26) and Fig. 1]. It shows a relatively long tail at large efflux volumes V, where the concentration varies at V^?3/2. For arbitrary values of a²/D_st the first three moments of the concentration versus time curve are calculated [eqs. (33)–(37)]. Pronounced skewness of the curve is found unless a²/D_st is small.     

Role of Ion exchange in permeation processes

The single ion transport of transition metal ions like Cu²⁺, Co²⁺, Ni²⁺ and Zn²⁺ were carried out through the H⁺ and alkali metal ion forms of Nafion membrane. These studies showed that the ion exchange selectivity coefficient of the permeating ion had an effect on its transport process. It was found that the diffusion coefficient values (D) were directly proportional to the selectivity coefficient (K). This shows that the initial stage of permeation is governed by ion exchange process (effect of K on D).     

Estimation of gas transport coefficients from differential permeation, integral permeation, and sorption rate data

Experimental methods for studying the transport of gases in polymers may be divided into three categories: integral permeation rate measurement, in which the cumulative amount of a penetrant that has passed through a membrane is determined; differential permeation rate measurement, in which the rate of penetration through a membrane is measured directly; and sorption rate measurement, or determination of the cumulative amount of a penetrant absorbed in a polymer sample. This paper reviews commonly used techniques for estimating diffusion coefficients from transport data of all three types. Several new estimation formulas are presented, and the relative merits of different measurement and estimation methods are discussed. A general relationship between the traditional time lag method for integral rate data analysis and a recently developed moment method for differential rate data analysis is established, extending the applicability of the moment approach to the analysis of non-ideal transport in membranes of arbitrary geometry and composition.