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PubMed1991

Disaccharide compositional analysis of heparin and heparan sulfate using capillary zone electrophoresis.

Capillary zone electrophoresis (CZE) was used to separate eight commercial disaccharide standards of the structure delta UA2X(1----4)-D-GlcNY6X (where delta UA is 4-deoxy-alpha-L-threo-hex-4-enopyranosyluronic acid, GlcN is 2-deoxy-2-aminoglucopyranose, S is sulfate, Ac is acetate, X may be S, and Y is S or Ac). These eight disaccharides had been prepared from heparin, heparan sulfate, and derivatized heparins. A similar CZE method was recently reported for the analysis of eight chondroitin and dermatan sulfate disaccharides (A. Al-Hakim and R.J. Linhardt, Anal. Biochem. 195, 68-73, 1991). Two of the standard heparin/heparan sulfate disaccharides, having an identical charge of -2, delta UA2S(1----4)-D-GlcNAc and delta UA(1----4)-D-GlcNS, were not fully resolved using standard sodium borate/boric acid buffer. This buffer had proven effective in separating chondroitin/dermatan sulfate disaccharides of identical charge. Resolution of these two heparin/heparan sulfate disaccharides could be improved by extending the capillary length, preparing the buffer in 2H2O, or eliminating boric acid. Baseline resolution was achieved in sodium dodecyl sulfate in the absence of buffer. The structure and purity of each of the eight new commercial heparin/heparan sulfate disaccharide standards were confirmed using fast-atom-bombardment mass spectrometry and high-field 1H-NMR spectroscopy. Heparin and heparan sulfate were then depolymerized using heparinase (EC 4.2.2.7), heparin lyase II (EC 4.2.2.-), heparinitase (EC 4.2.2.8), and a combination of all three enzymes. CZE analysis of the products formed provided a disaccharide composition of each glycosaminoglycan. As little as 50 fmol of disaccharide could be detected by ultraviolet absorbance.

Carbohydrate Sequence↗

PubMed2000

An investigation into the release of cefuroxime axetil from taste-masked stearic acid microspheres. II. The effects of buffer composition on drug release.

The influence of buffer composition on the release of cefuroxime axetil from stearic acid microspheres has been investigated, with particular emphasis on establishing the relationship between buffer composition and release at a single pH value. Studies of drug dissolution and release from spheres in pH 7.0 citrate phosphate buffer (CPB), boric acid buffer (BAB), phosphate buffer mixed (PBM) and Sorensens modified phosphate buffer (SMPB) indicated marked differences in release profile from the spheres, with an approximate rank order of SMPB > CPB approximately BAB > PBM. The role of added sodium was then investigated by examining the release profiles in SMPB and PBM to which sodium ions had been added. Increases in the sodium content from approximately 0.11 to 0.2 M were found to decrease the release rate for the SMPB, while increases from 0.007 to 1.0 M sodium in PBM resulted in a maximum release being seen for the systems containing 0.05 M sodium. Studies on surface disintegration, using scanning electron microscopy (SEM) and sodium uptake using flame emission spectroscopy, indicated an interrelationship between medium composition, disintegration and release. The data are discussed in terms of the possible mechanisms associated with drug release from these spheres.

Buffers↗

PubMed1966

Synthesis and characterization of 1- and 2-monoglycerides of anteiso fatty acids.

The branched-chain fatty acids D-(+)-12-methyltetradecanoic acid (C(15) anteiso) and D-(+)-14-methylhexadecanoic acid (C(17) anteiso) were isolated from the lipids of Listeria monocytogenes and their 1- and 2-monoglycerides were prepared. Reaction intermediates and products were purified without isomerization by column chromatography. Thin-layer chromatography on Florisil impregnated with boric acid and nuclear magnetic resonance were used in characterizing the 1- and 2-monoglycerides. The value of the latter method for analyzing glyceride structure is discussed.

Chemical Phenomena↗

PubMed1996

Separation of urinary thiols as tributyltinmercaptides and determination using capillary isotachophoresis.

The essential steps in the assay included electrolytic reduction of disulphides, neutralization, extraction of thiols with 0.1 M tributyltin hydroxide in octane, stripping of the extract with 2% acetic acid, fixing the washed-out amino thiols to a cation exchanger, elution with 2 M hydrochloric acid, oxidation with bromine and evaporation. The remaining octane extract was decomposed by dodecanethiol, the mercapto acids were washed out, oxidized with bromine and evaporated. Both residues were dissolved in water and analysed using capillary isotachophoresis at pH 3.0. Cysteamine was extracted from reduced urine at ca. pH 10, decomposed by dodecanethiol and re-extracted to boric acid followed by determination as a cation. The presence of the following thiols in urine has been confirmed: mercaptoacetic acid, 3-mercaptolactic acid, 2-mercaptopropionic acid, acetylcysteine, mercaptoethanol, cysteine, homocysteine and an un-identified amino thiol. Cysteamine and 3-mercaptopropionic acid could not be detected. Captopril, homocysteine and cysteine were determined quantitatively.

Antidotes↗

PubMed1998

Capillary electrophoresis of phospholipids with indirect photometric detection.

The capillary electrophoresis (CE) separation of different anionic phospholipid classes including phosphatidic acids (PA), phosphatidylserine, phosphatidylinositol, phosphatidylglycerol (PG), and cardiolipin using indirect detection with adenosine monophosphate (AMP) is described. A standard mixture of PAs (C14, C16, and C18) can be separated in 10 min by CE using 5 mM AMP and 100 mM boric acid in 10% water--80% methanol--10% acetonitrile. Although nonionic surfactants such as Brij 35 can improve the CE resolution of PAs, the separation time and the baseline noise are both increased. Optimization of the organic solvent in the running electrolyte is important. Methanol provides faster electroosmotic flow than propanol, and 10% acetonitrile effectively reduces migration time further by a factor of 1.4-2.2, depending on the phospholipid. The concentration limit of detection ranges from approximately 2 to 6 mg/L, and the mass limit of detection is as low as 21 pg. Linearity from 19 to 100 mg/L is established for cardiolipin and C16-PG. Phospholipids in soybean and brain extract samples could be profiled.

1-Propanol↗

PubMedDate not supplied

Determination of the concentration of complex boronated compounds in biological tissues by inductively coupled plasma atomic emission spectrometry.

The application of inductively coupled plasma atomic emission spectrometry (ICP-AES) to the determination of the concentration of complex boron-containing compounds in biological tissue samples is described. Tissue digestion is achieved with perchloric acid and hydrogen peroxide in 1 hr at 75 degrees C. The ICP-AES method gave a linear response for elemental boron concentration in the range 0.05 to 100 ppm and does not require the reduction of the boron to a simple species, such as boric acid. Complete recovery of boron in complex boron cluster compounds was obtained. The procedure has been applied to the determination of the boron content in compounds synthesised for neutron capture therapy and is suitable for use in biodistribution studies of such compounds.

Animals↗

PubMed1999

Simultaneous capillary electrophoretic separation of small anions and cations after complexation with ethylenediaminetetraacetic acid.

A new approach for simultaneous separation of small inorganic and organic anions and metal cations by capillary electrophoresis is demonstrated. Metal cations in the sample are transformed into their chelates with EDTA and are separated together with the anions using an anionic separation mode. Simultaneous separation of 19 common anions and cations was achieved in about 6 min with the electrolyte containing 5 mM K2CrO4, 3 mM boric acid, 35 microM cetyltrimethylammonium bromide and 12 microM EDTA at pH 8. Limits of detection (s/n = 3) were in the range from 4 ppb for Cl- up to 1250 ppb for Cu-EDTA and RSDs of peak areas ranged from 1.4% for Cl- up to 8.5% for Mn-EDTA chelate. The practical applicability of the method was demonstrated on the analysis of anions and cations in various water samples.

Anions↗

PubMed2001

[Analysis of tannins in Fructus Chebulae and its confusion varieties by HPCE].

AIM: To analyze the hydrolyzable tannins-chebulinic acid (I) and chebulagic acid(II) in Fructus Chebulae and its confusion varieties by using high performance capillary electrophoresis (HPCE) method. METHODS: Using a capillary (375 microns OD x 50 microns ID; 81.5 cm x 61.5 cm) and a power supply set at 24 kV, with phosphate-borate buffer containing 20 mmol.L-1 Na2HPO4-60 mmol.L-1 boric acid and a UV detector at 280 nm, sample solution was loaded in decompression mode at the positive end of the capillary, the loading time was 5 s. RESULTS: The linear ranges of I and II were 0.0842-0.842 and 0.842 and 0.0940-0.940 mg.mL-1 respectively, the correlation coefficient were 0.9966 and 0.9957, the average recoveries were 95.6% (RSD = 4.0%, n = 5) and 95.0% (RSD = 4.4%, n = 5), the RSDs (n = 5) of measurement precision test were 2.2% and 1.7%, the RSDs (n = 6) of reproduction test were 5.4% and 4.0% respectively. The contents of I and II were obviously interrelated with the variety and characteristics of Fructus Chebulae, the contents of I and II in the confusion varieties of Fructus Chebulae were very low. CONCLUSION: It is suitable to use I and II as the criterion in quality evaluation of Fructus Chebulae, and the HPCE method is effective for quality evaluation of the crude Fructus Chebulae.

Benzopyrans↗

PubMed2004

Micellar electrokinetic chromatography for the simultaneous determination of ketorolac tromethamine and its impurities. Multivariate optimization and validation.

A simple, fast and selective micellar electrokinetic chromatographic (MEKC) method for the simultaneous assay of ketorolac tromethamine and its known related impurities (1-hydroxy analog of ketorolac, 1-keto analog of ketorolac and decarboxylated ketorolac), in both drug substance and coated tablets, is described. The compounds were detected at 323 nm, and flufenamic acid (FL) and tolmetin (TL) were chosen as internal standards to quantify ketorolac tromethamine and impurities, respectively. The multivariate optimization of the experimental conditions was carried out by means of the response surface study, considering as responses the resolution values and analysis time. The optimized background electrolyte (BGE) consisted of a mixture of 13 mM boric acid and phosphoric acid, adjusted to pH 9.1 with 1 M sodium hydroxide, containing 73 mM sodium dodecyl sulfate (SDS). Optimal temperature and voltage were 30 degrees C and 27 kV. Applying these conditions, all compounds were resolved in about 6 min. The related substances could be quantified up to the 0.1% (w/w) level. Validation was performed, either for drug substances and drug product, evaluating selectivity, robustness, linearity and range, precision, accuracy, detection and quantitation limits and system suitability.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2004

Simple synthesis of diastereomerically pure phosphatidylglycerols by phospholipase D-catalyzed transphosphatidylation.

A simple method for synthesizing diastereomerically pure phosphatidylglycerols (PtdGro), namely, 1,2-diacyl-sn-glycero-3-phospho-3'-sn-glycerol (R,R configuration) and 1,2-diacyl-sn-glycero-3-phospho-1'-sn-glycerol (R,S configuration), was established. For this purpose, diastereomeric 1,2-O-isopropylidene PtdGro were prepared from 1,2-diacyl-sn-glycero-3-phosphocholine (PtdCho) and enantiomeric 1,2-O-isopropylideneglycerols by transphosphatidylation with phospholipase D (PLD) from Actinomadura sp. This species was selected because of its higher transphosphatidylation activity and lower phosphatidic acid (PtdOH) formation than PLD from some Streptomyces species tested. The reaction proceeded well, giving almost no hydrolysis of PtdCho to PtdOH in a biphasic system consisting of diethyl ether and acetate buffer at 30 degrees C. The isopropylidene protective group was removed by heating the diastereomeric isopropylidene PtdGro at 100 degrees C in trimethyl borate in the presence of boric acid to obtain the desired PtdGro diastereomers. The purities of the products, which were determined by chiral-phase HPLC, were exclusively dependent on the optical purities of the original isopropylidene-glycerols used. The present method is simple and can be utilized for the synthesis of pure PtdGro diastereomers having saturated and unsaturated acyl chains.

Bacterial Proteins↗

PubMed2001

Development of an improved medium for germination of Cajanus cajan (L.) Millsp. pollen in vitro.

A simple, reliable medium for pollen germination of Cajanus cajan was developed by modifying Brewbaker and Kwack (BK) medium. Past attempts of C. cajan pollen germination in artificial media were not successful. A medium containing polyethylene glycol 4000 (PEG) showed more than 90% germination for C. cajan var. Pusa 33 only when the young buds (36 h before anthesis) were kept in pollen germination medium (PGM) for 36 h before pollen extraction. Supplementation of PGM with epsilon-amino caproic acid (EACA), an amino acid, showed improved pollen germination in Pusa 33 and also helped to avoid preconditioning of young buds before pollen extraction. It was also observed that there is a genotypic difference in the level of EACA required for in vitro pollen germination. Thus a complete medium for C. cajan genotypes consists of 37.5% sucrose+ 15% PEG 4000+250 mg l(-1) boric acid+300 mg l(-1) calcium nitrate+100 mg l(-1) potassium nitrate+ 200 mg l(-1) magnesium sulphate+1% agar+EACA (0, 100, 250, 500, 750 or 1000 mg l(-1)).

Culture Media↗

PubMed2006

The effects of excess boron with niacin on Daucus carota L. (carrot) root callus.

Niacin (Nicotinic acid, B3 vitamin) may be involved in reduction of toxic effects of boron by regulating growth metabolism. This study was designed to examine whether external niacin treatment would improve the boron mobility in carrot callus cells or not. The results showed that excess boron caused tracheary inversions in meristematic root tissue, and also a shortage was seen in tracheary lengths with boric acid treatment. Boron excess induced the plant tolerance to water stress inverting the tracheary cells. This shortage converted nearly to normal size with niacin and boron treatment together. The results showed that boron mobility induced by niacin could reduce significantly the fresh and dry weight of carrot root cells, protein and ABA content was reduced also, in contrary, external boron and boron with niacin treatment considerable increased the two factors after one month stress. Fresh weight reduction and ABA content reduction indicated that niacin treatment caused water stress on the root cells of carrot, but boron treatment and boron with niacin treatment increased drought tolerance in carrot cells by increasing the both factors. In addition, turning the conversion of the length of the trachearies to their normal size proved that niacin treatment ended the polarizing effects of boron on cell walls.

Abscisic Acid↗

PubMedDate not supplied

Determination of borates in caviare by ion-exclusion chromatography.

A specific and rapid analytical procedure for the determination of borates in caviare was developed using ion-exclusion chromatography. Products require minimal pre-treatment, are simply extracted with eluent and filtered prior to chromatography. Isolation of the analyte as a 2:1 sorbitol-borate complex was accomplished using an anion exchange column with an eluent consisting of 2 mM heptafluorobutyric acid + 50 mM sorbitol with conductivity detection [corrected]. Among five sugar alcohols examined for complexation, sorbitol was found to provide optimum resolution and a 3-4 times enhancement of response over borate anion alone. The response of the complex was linear over at least a 100 fold range in concentration (0.1-10 micrograms boron/ml) with a correlation coefficient of 0.9997. Using a boric acid standard solution, the limits of detection and quantitation were 0.065 microgram/ml and 0.216 microgram/ml, respectively, calculated as boron. Replicate analyses (n = 5) for samples having commercially added borate (equivalent to 300-1000 micrograms/g boron) gave RSD values of 1.18-2.03%. Recoveries of borate from fortified samples having commercially added borate present varied from 94.5 to 101.1% while untreated samples exhibited recoveries of 78.5-108.0% over a concentration range of 23-1039 micrograms/g, calculated as boron.

Animals↗

PubMed2000

Optimization of the separation of phenolic compounds by micellar electrokinetic capillary chromatography.

A group of phenolic compounds including phenolic aldehydes, acids and flavonoids are separated by micellar electrokinetic chromatography (MECC). The influence of buffer (concentration and pH), concentration of sodium dodecylsulphate (SDS) and applied voltage were studied. To increase the selectivity of the separation and the resolution of the solutes organic solvents are added to the separation buffer, the best results were obtained when methanol was used at lower percentages. An optimized buffer (150 mM boric acid (pH 8.5)-50 mM SDS-5% methanol) provides the optimum separation with regard to resolution and migration time. This method was applied to the determination of these compounds in wine samples with good results.

Buffers↗

PubMed2001

[Determination of 4-aminobutyric acid in pumpkin powder by high performance liquid chromatography].

A method for the separation and determination of the 4-aminobutyric acid in pumpkin powder by high performance liquid chromatography (HPLC) with post-column derivatization and fluorescence detection is described. The operating conditions were cation exchange resin column (30 cm x 0.4 cm i.d.) with gradient elution of buffer solutions A [19.6 g sodium citrate dihydrate and 1.0 g phenol dissolved in 1 L water, pH(3.15 +/- 0.02)] and B [21.0 g sodium nitrate and 1.5 g boric acid dissolved in 1 L water, pH(9.70 +/- 0.02)] as mobile phase at a flow rate of 0.5 mL/min, and a column temperature of 62 degrees C, with detection wavelength lambda ex = 338 nm, lambda em = 425 nm. The retention time of 4-aminobutyric acid was 34.77 minutes. The average recovery was 99% and the coefficient of variation was 1.35%. This method is simple, rapid and sensitive.

Cation Exchange Resins↗

PubMed1996

Complete capillary electrophoretic separation of substance P and its metabolites at neutral pH using ionic run buffer additives.

Substance P (SP), a bioactive peptide that is present in the extracellular fluid of the brain at picomolar concentrations, has been proposed to be a neurotransmitter and a neuromodulator in the central and peripheral nervous systems. This paper describes the development of analytical methodology for the separation of SP and its metabolites by capillary electrophoresis at neutral pH. Since SP is a cationic peptide, it tends to adsorb to silica surfaces. In this work, phytic acid was employed as a run buffer additive to eliminate the interaction of SP and its cationic N-terminus metabolites with ionized silanol groups. The separation of the C-terminus metabolites was then accomplished through the use of sulfobutyl ether beta-cyclodextrin, which imparted a negative charge to these otherwise neutral metabolites through complexation of the phenylalanine residue. The final separation buffer consisted of 150 mM boric acid, 15 mM phytic acid and 5 mM SBE(IV)beta-cyclodextrin at pH 7. Under these conditions, it was possible to separate SP from all eight of its reported metabolites.

Amino Acid Sequence↗

PubMed2001

Enantiomeric separations of primary amino compounds by capillary electrochromatography with monolithic chiral stationary phases of chiral crown ether-bonded negatively charged polyacrylamide gels.

A novel enantiomeric separation method by capillary electrochromatography with chiral crown ether-bonded negatively charged polyacrylamide gels is presented. Two kinds of chiral crown ether derivatives, (+)-tetraallyl 18-crown-6 carboxylate and (+)-18-crown-6 tetracarboxylic acid 2-allyl ester were synthesized and allowed to covalently bind to a negatively charged polyacrylamide gel, a so-called monolithic stationary phase, respectively. The gel was placed in fused-silica tubing, the walls of which had been activated with a bifunctional reagent to make the resulting gel bind covalently to the inner surface. Enantiomeric separations of 12 primary amino compounds were achieved using these columns and mobile phases of 200 mM triethanolamine-300 mM boric acid buffers with high efficiencies of up to 135000 plates m(-1). Both the within- and between-run reproducibilities of retention time and separation factor were good. The reproducibilities of retention time and separation factor for three different columns prepared from a different batch of monomers were acceptable. The gel-filled capillaries were stable for at least 13 months with intermittent use for 3 months followed by storage at room temperature for 10 months. The result of the optical purity test of alanine-2-naphthylamide is also described.

Amines↗

PubMed1991

Microdetermination of hyaluronic acid in human urine by high performance liquid chromatography.

A high performance liquid chromatographic (HPLC) system is described for determination of the unsaturated disaccharide (delta Di-HA) derived from hyaluronic acid (HA) in human urine by digestion with hyaluronidase SD. The effects of eluents on the separation of delta Di-HA and delta Di-0S, which is derived from the reaction of chondroitin with the enzyme, have been studied. The established chromatographic conditions were as follows--column: a stainless steel tube (4 mm i.d. x 250 mm) packed with TSKgel NH2-60; eluent: a mixture of acetonitrile and 0.1 M Tris-HCl buffer containing 0.1 M boric acid and 10 mM sodium sulphate, pH 7.0 (64:36, v/v). The strong fluorescence of unsaturated disaccharide after the reaction with 2-cyanoacetamide in alkaline medium was used for post-column detection. The calibration curve for delta Di-HA was linear in the range 5 pmol-5nmol with a practical detection limit of 2 pmol. The assay coefficients of variation (n = 5) at 200 pmol for delta Di-HA and delta Di-0S were 1.7 and 1.5%, respectively. This HPLC system has been applied to the determination of HA in human urine.

Adult↗