Increasing the scale of true moving bed electrophoretic separations using filtration to reduce solvent volumetric flows between sections II and III

Over the past decade the moving bed process has become a commonly used tool for the continuous separation of chiral compounds, and its recent application to electrophoretic separations allows the technique to be used as a model system for moving bed method improvements. Much of the recent research on moving bed separations has focused on improving the technique's efficiency and increasing the maximum attainable throughput. This paper presents a novel method for reducing or reversing the increases in tailing that stem from the addition of the feed stream in a moving bed process by adding a filtration unit which retains the products while removing fluid from the boundary between the sections above and below the feed stream. This filtration-enhanced moving bed process was applied to a true moving bed (TMB) electrophoresis separation in the Vortex Stabilized Electrophoresis Apparatus, and its effect on a homatropine enantiomer separation was studied. Experiments showed that there is a 2.4-fold increase in the homatropine processing rate when 0.5 ml/h of water is removed through a reverse osmosis filter at the boundary between the sections above and below the feed stream. In order to further understand the process, filtration-enhanced TMB (FE-TMB) was also analyzed using a linear model of the system which shows that the 99% purity operating region of the separation is greatly increased even with moderate permeate flowrates.

Hepatic angiomyolipoma with trace amounts of fat: a case report and literature review

Hepatic angiomyolipoma (AML), a rare benign mesenchymal tumour, is characterised by the presence of mature adipose tissue, smooth-muscle cells and thick-walled blood vessels. Increasing attention to hepatic AMLs has led to the discovery that sufficient proportions of fat often allow for definite diagnoses preoperatively. However, the proportion of fatty tissue in these tumours is highly variable. One case of hepatic AML is reported, where the amount of fat was <1%. In this case, the viral hepatitis markers, including hepatitis B antigen and anti-hepatitis C virus antibody, were negative. The serum alpha-fetoprotein level was 3.4 ng/ml and in the normal range. Abdominal ultrasonography showed a hypoechoic mass measuring 5 cm in diameter and without an obvious capsule in the left lobe of the liver. A dynamic computed tomography scan showed a well-defined and slightly enhanced mass in the medial segment of the left lobe of the liver. Angiography showed that the mass was hypervascular in character. As hepatocellular carcinoma was highly suspected from these preoperative image studies, a left lobectomy was carried out. Microscopically, the amount of fat was too low to establish a diagnosis of hepatic AML. However, positive homatropine methylbromide 45 immunoreactivity of the smooth-muscle cells seemed to assist in arriving at the diagnosis.

Determination of anatoxin-a in environmental water samples by solid-phase microextraction and gas chromatography-mass spectrometry

In the present work, a method was developed and optimized aiming at the determination of anatoxin-a in environmental water samples. The method is based on the direct derivatization of the analyte by adding hexylchloroformate in the alkalinized sample (pH = 9.0). The derivatized anatoxin-a was extracted by a solid-phase microextraction (SPME) procedure, submersing a PDMS fiber in an amber vial for 20 min under magnetic stirring. GC-MS was used to identify and quantify the analyte in the SIM mode. Norcocaine was used as internal standard. The following ions were chosen for SIM analyses (quantification ions in italics): anatoxin-a: 191, 164, 293 and norcocaine: 195, 136, 168. The calibration curve showed linearity in the range of 2.5-200 ng/mL and the LOD was 2 ng/mL. This method of SPME and GC-MS analysis can be readily utilized to monitor anatoxin-a for water quality control.

Identification of isomeric tropane alkaloids from Schizanthus grahamii by HPLC-NMR with loop storage and HPLC-UV-MS/SPE-NMR using a cryogenic flow probe

Two fully automated HPLC-NMR methods are reported and compared for the structure elucidation of four isomeric tropane alkaloids from the stem-bark of an endemic Chilean plant, Schizanthus grahamii Gill. (Solanaceae). The first approach interfaced a conventional HPLC column to NMR by means of a loop storage unit. After elution with a mobile phase consisting of deuterated water and standard protonated organic solvents, the separated analytes were momentarily stored in a loop cassette and then transferred one-at-a-time to the NMR flow probe for measurements. The second strategy combined HPLC with parallel ion-trap MS detection and NMR spectroscopy using an integrated solid-phase extraction (SPE) unit for post-column analyte trapping. The SPE cartridges were dried under a gentle stream of nitrogen and analytes were sequentially eluted and directed to a cryogenically cooled flow-probe with an NMR-friendly solvent. The structures of the four isomeric alkaloids, 3alpha-senecioyloxy-7beta-hydroxytropane, 3alpha-hydroxy-7beta-angeloyloxytropane, 3alpha-hydroxy-7beta-tigloyloxytropane and 3alpha-hydroxy-7beta-senecioyloxytropane, were unambiguously determined by combining NMR assignments with MS data.

Cocaine distribution in wild Erythroxylum species

Cocaine distribution was studied in leaves of wild Erythroxylum species originating from Bolivia, Brazil, Ecuador, Paraguay, Peru, Mexico, USA, Venezuela and Mauritius. Among 51 species, 28 had never been phytochemically investigated before. Cocaine was efficiently and rapidly extracted with methanol, using focused microwaves at atmospheric pressure, and analysed without any further purification by capillary gas chromatography coupled to mass spectrometry. Cocaine was reported for the first time in 14 species. Erythroxylum laetevirens was the wild species with the highest cocaine content. Its qualitative chromatographic profile also revealed other characteristic tropane alkaloids. Finally, its cocaine content was compared to those of two cultivated coca plants as well as with a coca tea bag sample.

Analysis of isomeric tropane alkaloids fromSchizanthus grahamii by very fast gas chromatography

This study presents a very fast GC analysis applied for the baseline separation of isomeric tropane alkaloids extracted from the stem-bark of Schizanthus grahamii (Solanaceae). The work provided a challenging application where isothermal analysis in conjunction with very short narrow bore columns (3 m x 100 microm ID and 1.5 m x 50 microm ID) was particularly suited for the speeding up. Experimental parameters were used in the optimisation steps, including selection of stationary phase, temperature, internal column diameter and optimal practicable gas velocity. Some considerations about sample injection in fast isothermal analysis are also briefly presented. Finally, the investigated approach allowed a very fast baseline separation of four positional and configurational isomers in less than 9 s.

Separation of four isomeric tropane alkaloids from Schizanthus grahamii by non-aqueous capillary electrophoresis

The potential of non-aqueous capillary electrophoresis was investigated for the separation of four isomeric tropane alkaloids, namely 3alpha-senecioyloxy-7beta-hydroxytropane, 3alpha-hydroxy-7beta-senecioyloxytropane, 3alpha-hydroxy-7beta-angeloyloxytropane and 3alpha-hydroxy-7beta-tigloyloxytropane extracted from Schizanthus grahamii. The composition of the organic solvent and the nature of the electrolyte were of considerable importance with respect to selectivity. Different organic solvents (i.e. methanol, ethanol, acetonitrile, tetrahydrofuran) and mixtures thereof were investigated. Moreover, different electrolytes such as formate, acetate and trifluoroacetate were tested. After optimisation, an electrolyte consisting of 1 M trifluoroacetic acid and 25 mM ammonium trifluoroacetate in methanol:ethanol (40:60, v:v) was selected. It provided an efficient separation of the four positional isomers as well as a good repeatability of migration time (RSD < 0.2%). The method was successfully used with electrospray MS to confirm the molecular mass of the tropane alkaloids.

Winter Cherry Bugs Feed on Plant Tropane Alkaloids and De-epoxidize Scopolamine to Atropine

The winter cherry bug colonizes the Duboisia leichhardtii tree, which is a rich source of scopolamine. It consumes the tropane alkaloids atropine and scopolamine. Quantitative analysis revealed that the ratio of scopolamine to atropine in the winter cherry bug (0.46) was far from that found in the leaves of the host plant (7.20). To elucidate whether the winter cherry bugs selectively excrete or decompose scopolamine, they were fed scopolamine and/or atropine together with sucrose. They took up scopolamine as well as atropine, and converted scopolamine into atropine.

Preparing for chemical terrorism: stability of injectable atropine sulfate

OBJECTIVE

A massive nerve agent attack may rapidly deplete in-date supplies of atropine. The authors considered using atropine beyond its labeled shelf life. The objective was to determine the stability of premixed injectable atropine sulfate samples with different expiration dates.

METHODS

This was an in-vitro study using gas chromatography and mass spectrometry (GC/MS). Four atropine solutions (labeled concentration of 400 microg/mL) ranging from in date to 12 years beyond expiration (exp) and an additional sample of atropine sulfate (labeled concentration of 2,000 microg/mL) obtained from a World War II era autoinjector were assayed for atropine stability. Standards of atropine sulfate and tropine were prepared and quantified by GC/MS. Study samples were prepared by adding a buffer solution to free the base, extracting with an isopropanol/methylene chloride mixture and followed by evaporating the organic layer to dryness. Pentafluoropropionic anhydride and pentafluoropropanol were then added as derivatization reagents. Study samples were heated, the derivitization reagents were evaporated, and the remaining compound was reconstituted in ethyl acetate for injection into the GC/MS.

RESULTS

All solutions were clear and colorless. Atropine concentrations were as follows: in date, 252 microg/mL; 2001 exp, 290 microg/mL; 1999 exp, 314 microg/mL; 1990 exp, 398 microg/mL; and WW II specimen, 1,475 microg/mL. Tropine was found in concentrations of <10 microg/mL in all study samples.

CONCLUSIONS

Significant amounts of atropine were found in all study samples. All samples remained clear and colorless, and no substantial amount of tropine was found in any study sample. Further testing is needed to determine clinical effect.

RP-HPLC separation of the diastereomers of technetium-99m labelled tropanes and identity confirmation using radio-LC-MS

99mTc-TRODAT-1 (technetium(V)-oxo-2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]]amino]-ethanethiolato(3-)) and 99mTc-TRODAT-M, the 4-methylphenyl derivative of 99mTc-TRODAT-1, are at this moment being evaluated in clinical trials as imaging agents for the central nervous dopamine transporter system. Both compounds are formed as a mixture of two major diastereomers. As the tracer concentration in preparations for clinical investigations is very low (30-150 pmol/ml), identification of these 99mTc-complexes was, up to now, carried out indirectly using X-ray diffraction analysis of the corresponding rhenium complexes which can be synthesized in gram amounts. In this study, we developed a convenient and practical reversed phase HPLC-method for purification and isolation of the respective diastereomers of 99mTc-TRODAT-1 and three of its derivatives using mixtures of solvents which are compatible with biological studies, i.e. aqueous buffers and ethanol. Furthermore, direct identity confirmation of the 99mTc-complexes using radio-LC-MS was successfully elaborated.

Analysis of tropane and related alkaloids

The current methods for tropane alkaloid chromatographic separation and determination are summarised. The alkaloids included are: the medicinally applied tropic acid esters hyoscyamine and scopolamine and their derivatives, cocaine and derivatives, the metabolites and degradation products of these compounds occurring in plant material, calystegines as nortropane alkaloids, anatoxins as homonortropane alkaloids, pelletierines and pseudopelletierines as alkaloids with isomeric structures. Developments in GC, HPLC, CE and TLC are presented and the advantages of each method for plant analysis are discussed. A summary for each chromatographic method lists the instrumentation and parameters applied for tropane alkaloids.

Tropane alkaloids in pharmaceutical and phytochemical analysis

Alkaloids with tropane skeleton, present in many species of Solanaceae family, constitute important raw materials for variety of pharmaceutical preparations. Although basic facts concerning chemistry and pharmacology of these compounds date back to XIX century, the wealth of data, accumulated recently, has challenged many established opinions, particularly in the field of biogenesis. Advances in analytical techniques which made this progress possible are discussed, in reference to contemporary requirements for specification of active pharmaceutical ingredients.

Membrane disruption and enzyme inhibition by naturally-occurring and modified chacotriose-containing Solanum steroidal glycoalkaloids

Naturally-occurring 3beta-O-chacotriosides of solasodine (solamargine), of its 22S, 25S isomer tomatidenol (beta-solamarine), and of solanidine (chaconine), as well as ring E- and F-modified derivatives of solamargine were prepared and assayed in order to assess the relevance of aglycone structural features to membrane-disruption and enzyme-inhibitory activities of the related glycoalkaloids. A ring E-opened dihydro-derivative of solasodine (the chacotrioside of dihydrosolasodine A) did not bind to cholesterol, stigmasterol or ergosterol in vitro, disrupt PC/cholesterol liposomes or mammalian erythrocytes. or inhibit acetylcholinesterase in vitro. It did not synergise with the solatrioside of dihydrosolasodine A or solasonine (nor did solamargine with dihydrosolasodine A solatrioside) in haemolysis tests. The ring F modified derivative, N-nitrososolamargine, did not inhibit acetylcholinesterase in vitro, but lysed liposomes at > or = 150 microM and pH 7. Increasing the pH to 8 (but not 9) further enhanced disruption. The combination of N-nitrososolamargine and solasonine did not cause any disruption of liposomes. Beta-solamarine showed no anti-acetylcholinesterase activity in vitro at up to 100 microM, but disrupted liposomes at 75 and 150 microM, although not to the extent caused by solamargine or chaconine. In combination with both the (inactive) solatriosides, solasonine and solanine, 75 microM beta-solamarine produced synergistic effects, with liposome disruption greater than 150 microM beta-solamarine alone. Beta-solamarine, solamargine and chaconine showed similar haemolytic activity. Beta-solamarine synergised with the solatriosides solasonine and solanine in disrupting erythrocytes. Preliminary structure-activity relationships were evaluated for the active chacotriosides in an attempt to define the scope and limitations of this model study.

Tris(2,2'-bipyridine)ruthenium(II) electrogenerated chemiluminescence of alkaloid type drugs with solid phase extraction sample preparation

An electrogenerated chemiluminescence (ECL) method for the determination of pethidine, atropine, homatropine and cocaine is described. The optimum conditions were found to be similar for all of these compounds although the ECL emission intensity for cocaine was an order of magnitude lower than for pethidine due to their different chemical structures. Linear calibrations were obtained for all the compounds at pH 10 in borate buffer (0.05 mol l-1) at 1.3 V. Limits of detection of 6.8 x 10(-8), 2.2 x 10(-7), 3.2 x 10(-7) and 6.5 x 10(-7) mol l-1, respectively, were achieved for pethidine, atropine, homatropine and cocaine in standard solutions. Solid-phase extraction was used to separate the drugs from their matrix and the method was applied to the determination of spiked urine samples. The limits of quantitation for pethidine, atropine, homatropine and cocaine in urine were 1.0 x 10(-6), 2.0 x 10(-6), 2.0 x 10(-6) and 4.0 x 10(-6) mol l-1, respectively, with recoveries of between 90 and 110%.

[Angel trumpet: a poisonous garden plant as a new addictive drug?]

BACKGROUND AND OBJECTIVE

Angel's trumpet (Species Brugmansia) is widely used as a garden plant because it is easily kept and the luxuriance of its flowering. Belonging to the Family Solanacea it contains a large amount of alkaloids (parasympatholytics). Because of its hallucinogenic action, its leaves and flowers are increasingly used by young people as a substitute for the hallucinogen LSD (lysergic acid diethylamide). In the summer of 1997, one of a group of youths died after they had ingested its flowers which they had gathered from front gardens. An investigation was undertaken to identify the alkaloids and measure their concentration in the various parts of the plant.

METHODS

Four young and one eight-year old plant were kept outdoors from May until October, and its flowers and leaves were removed for analysis weekly. All samples were deep-frozen at -20 degrees C and later, at the same time, thawed out, weighed and extracted in methanol. The alkaloids were identified by high pressure liquid chromatography (HPLC), diode array detector, separated by means of a Hypersil HyPurity cartridge, and measured at a wave-length of 220 nm.

RESULTS

All 66 flowers, 32 leaves and 2 speed capsules contained tropane alkaloids, mainly scopolamine. The highest concentrations were found in the seed capsules, lower ones in the flowers, while the leaves contained only small amounts. Total alkaloid content per flower of the younger plants averaged 0.94 mg, of the younger ones 1.81 mg. The flowers of the old plant contained up to 3 mg scopolamine.

CONCLUSION

The ingestion of even a few flowers of Angel's trumpet can cause symptoms of poisoning. Easy availability of the plant thus presents a danger. Because of the increasing incidence of deliberate ingestion by young people, poisoning by Angel's trumpet should be included in the differential diagnosis in patients with confusion and hallucinations of uncertain origin, especially during the summer months.

Selectivity manipulation using nonaqueous capillary electrophoresis. Application to tropane alkaloids and amphetamine derivatives

Non-aqueous capillary electrophoresis was investigated for its potential in the analysis of pharmaceutical compounds, namely tropane alkaloids and amphetamine derivatives. The separation of these drugs was compared in aqueous and organic media such as methanol and/or acetonitrile. Selectivity, migration times and efficiency were critically affected by the composition of the methanol/acetonitrile mixture, as well as by the nature and the concentration of the electrolyte. In particular, the migration orders of two positional isomers, littorine and hyoscyamine, were inverted in the presence of trifluoroacetic acid in the nonaqueous medium. The same behavior was observed for amphetamine-methamphetamine and for two methylenedioxyamphetamine derivatives.

Development and validation of a capillary zone electrophoresis method for the determination of atropine, homatropine and scopolamine in ophthalmic solutions

A capillary zone electrophoresis method is described for the simultaneous determination of atropine, homatropine and scopolamine. Successful results were obtained after optimization of the electrophoretic parameters such as buffer composition and pH. The best separation was achieved using a 100 mM Tris-phosphate running buffer at pH 7. The validation data proved that the method had the requisite selectivity, sensitivity, reproducibility and linearity to be used for the assay of these compounds in pharmaceutical formulations. Dosage of the separate drugs in ophthalmic preparations is also presented.

Antinociception induced by SM 32 depends on a central cholinergic mechanism

The antinociceptive effect of SM 32 was examined in mice by using the hot-plate (10-40 mg kg(-1) i.p; 3-30 microg per mouse i.c.v.) and abdominal constriction (10-30 mg kg(-1) i.p) tests. In the antinociceptive dose-range, SM 32 did not impair mouse spontaneous motility and motor coordination evaluated respectively by the Animex and rota-rod tests. The increase in the pain threshold produced by SM 32 was prevented by dicyclomine, pirenzepine and hemicholinium-3 but not by naloxone and CGP 35348. In vitro experiments showed that the SM 32 amplified electrically- and nicotine-evoked guinea-pig ileum contractions. On the basis of the above data, it can be postulated that SM 32 exerts its antinociceptive effect through a potentiation of central cholinergic transmission.

[Determination of scopolia extract in commercial gastrointestinal drugs by high-performance liquid chromatography]

Tropane alkaloids, contained in gastrointestinal drugs including Scopolia Extract, were determined using high-performance liquid chromatographic method. Tropane alkaloids in commercial drugs were extracted with 0.5 N hydrochloric acid test solution. This solution was adjusted to pH 10.0 with a strong ammonia solution, extracted with ethyl ether, and separated on TSKgel ODS-120T (4.6 mm i.d. x 15 cm; temperature, 30 degrees C; flow rate, 1.5 ml/min; detector, UV 210 nm) with a mixture of 1/15 M sodium phosphate buffer (pH 2.5) and acetonitrile (68:32) containing 12 mM sodium dodecyl sulfate. The contents of atropine in the gastrointestinal drugs were 0.25-0.34 mg (coefficient of variation = 0.20-2.61%) a day.

Analysis of tropane alkaloids with thermospray high-performance liquid chromatography-mass spectrometry

A thermospray high-performance liquid chromatography-mass spectrometry method for analysis of hyoscyamine and scopolamine in plant cell culture samples is described. The alkaloids were separated on a polymeric reversed-phase column with an alkaline ammonium acetate buffer-acetonitrile eluent. Selected-ion recording of the protonated molecular ions was used for quantitation of the compounds. The compounds were fragmented by discharge-assisted ionization and elevated thermospray capillary temperatures or ion repeller potentials.

Structural comparison of the potent antimuscarinic agent azaprophen hydrochloride with aprophen hydrochloride and structurally related antimuscarinic agents

A comparison of the crystalline structure of the potent azaprophen with the crystalline structures of aprophen and four other structurally related antimuscarinic agents reveals the potential for an ionic interaction of the cationic nitrogen atom and the carbonyl oxygen atom with the muscarinic receptor and an aromatic interaction with a phenyl group. 6-Methyl-6-azabicyclo[3.2.1]octan-3 alpha-ol 2,2-diphenylpropionate hydrochloride (azaprophen hydrochloride), C23H28NO2+.Cl-, Mr = 385.9, monoclinic, P2(1)/c, a = 8.490 (1), b = 14.335 (2), c = 16.847 (2) A, beta = 93.63 (1) degree, V = 2046.2 A3, Z = 4, Dx = 1.253 g cm-3, Cu K alpha, lambda = 1.54178 A, mu = 17.86 cm-1, F(000) = 824, room temperature, final R = 4.25% for 2460 reflections with [Fo[ greater than 3 sigma. 2-Diethylaminoethyl 2,2-diphenylpropionate hydrochloride (aprophen hydrochloride), C21H28NO2+.Cl-, Mr = 361.9, orthorhombic, Pbca, a = 15.118 (3), b = 7.488 (2), c = 36.306 (10) A, V = 4110.8 A3, Z = 8, Dx = 1.316 g cm-3, Cu K alpha, lambda = 1.54178 A, mu = 17.45 cm-1, F(000) = 1552, room temperature, final R = 7.96% for 1846 reflections with [Fo[ greater than 3 sigma. Both azaprophen and aprophen were crystallized as tertiary amine salts. The overall conformation of both molecules is similar as demonstrated by space-filling models and superimposed stick drawings. Although the interatomic distance between the nitrogen atom and the carbonyl oxygen atom of azaprophen and aprophen is comparable at 5.41 and 5.07 A, respectively, the nitrogen atoms of azaprophen and aprophen are 1.16 A apart when the acyloxy portion (--O--C = O) of both molecules is superimposed. A conformational analysis of azaprophen, aprophen and the structurally similar antimuscarinic agents reveals a buried ether oxygen atom and an exposed carbonyl oxygen atom as well as the common placement of a phenyl group on the same side of the acyloxy plane as the cationic nitrogen atom.(ABSTRACT TRUNCATED AT 250 WORDS)