Abstract  The adsorption energy distributions (AEDs) of methanol and dichloromethane on samples of the same silica unmodified and modified with octadecyldimethylsilyl (C-18) were estimated from isotherm data obtained by inverse gas chromatography at finite concentration. Wall-coated open tubular columns were used as they provide a high efficiency and a low pressure drop, allowing the acquisition of accurate isotherm data. The adsorption isotherms were obtained from nonlinear elution profiles using the characteristic points method of chromatography. The numerical estimation of AEDs was made by applying the expectation-maximization method to the experimental, unfitted adsorption isotherm data. The adsorption energy distributions obtained exhibit two peaks of adsorption energy. The height of the higher energy peak is reduced after chemical modification of the silica surface.

Abstract  Methods for the chromatographic analysis of lipophilic extractives (resin) in radiata pine wood, bisulfite pulp and mill pitch samples are described. The mass of substances extracted from fresh wood samples decreased as the polarity of solvents decreased, in the order methanol > acetone > dichloromethane > hexane. However The amounts of individual lipophilic extractives analysed were not as dependent on extraction solvent. High performance size exclusion chromatography (HPSEC) separated the extracts into four fractions namely triglycerides, steryl esters, sterols and fatty acids, and resin acids. Gas chromatography-mass spectrometry (GC-MS) of trimethylsilyl (TMS) derivatives of the extracts gave good separation of resin acids and fatty acids as their TMS esters, and of sterols as their TMS ethers The pitch sample consisted mainly of salts of fatty acids, with smaller amounts of resin acid salts, sterols and steryl esters, and only trace amounts of triglycerides. It is concluded that the combination of GC-MS and HPSEC is useful for the analysis of radiata pine extractives, allowing the estimation of individual resin and fatty acids and steroids, and total amounts of steryl esters and triglycerides.

Abstract  The present investigation reports on the larvicidal activity of a) bark of Bischofia javanica, Cinnamomum zeylanicum, and Givotia mollucana, b) leaf of Morinda umbellata, Trichopus zeylanicus, Erythroxylon monogynum, Oxalis carnicualata, Solanum verbasicum and Vitex negundo and c) shoot with leaves of Leucas aspera. Solvent residues of these plant components obtained from hexane, diethyl ether, dichloromethane, ethyl acetate and methanol extracts and later dissolved in acetone were separately tested at 1000 ppm on third instar larvae of Culex quinquefasciatus for insecticidal effects. Residues of these solvent extracts procured from shoot with leaves of Leucas aspera and leaves of Vitex negundo were only found to be very effective at such dosage resulting in 100% mortality of the larvae within 24, 48 or 72 h of treatment. However, the mortality was significantly reduced at lower dosages (100, 300 or 500 ppm). Solvent residues of the tested plant parts from the remaining eight Botanicals exhibited relatively less toxicity to these larvae in varying degrees in relation to exposure time and dosage.

Abstract  Antibiotics used in both human and veterinary medicine make an important group of drags. However, the use of these compounds causes their expansion into the environment, where there accumulate and develop their resistance. It is documented that they block biological processes in wastewater treatment plants. They also affect natural ecosystems and may concentrate in food chain. Sulfonamides (widely known as "sulfa drags") were the first antimicrobial drags used in medicine. They are deri-vates of p-aminobenzenesulfonamide and are used as antimicrobial drags in both veterinary and human medicine. A large number of human and animal infectious diseases is treated by these compounds. The analysis of sulfonamides is highly influenced by their properties, mainly by their insolubility in water, etha-nol, ether and dichloromethane. The samples were collected from the municipal and veterinary wastewater treatment plants in Brno, the Czech Republic. The simple extraction method for sulfonamides (sulfathiazole) in wastewater has been developed. Sulfathiazole was extracted by liquid-liquid extraction with ethy-lacetate and evaporated using a rotary vacuum evaporator. The evaporation residues were dissolved in methanol and mobile phase. The mixture of acetonitrile and 0.1% formic acid in ultrapure water was used as the mobile phase. The samples were filtered into the amber glass vials through membrane filters. The HPLC instrument equipped with a diode array detector was used to perform the sample analysis. The concentration levels of sulfathiazole in real samples are discussed in this paper.

Abstract  Asymmetric membranes based on a poly(ether ether ketone) with a phthalido group along the polymeric backbone (PEEKWC) were prepared by non-solvent induced phase separation. Three chlorinated solvents (i.e. chloroform, dichloromethane and 1,2-dichloroethane - TCM, DCM and DCE in the following), at fixed evaporation times between casting and coagulation in methanol, have been used to investigate the effect of different evaporation rates on the formation of the skin layer structure. The surface morphology of the membranes has been determined by AFM. Membranes prepared by using DCM and TCM as solvents are characterized by the presence of a dense skin layer with different grain size, whereas a porous skin layer is formed with DCE. These differences arise from the volatility (DCm > TCM > DCE) and the solvation ability (DCM < DCE

Abstract  Calendula sp. is an important medicinal and industrial plant with various bioactivities. In this study, we examined enzyme inhibitory effects of the n-hexane, dichloromethane, acetone, ethyl acetate, methanol, and water extracts of the leaf and flowers of Calendula arvensis L. and C. officinalis L. against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The extracts were screened for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion-chelating capacity and ferric-reducing antioxidant power (FRAP) assays at 250, 500, and 1000 I14g mL super(-1. Total phenol and flavonoid quantification of the extracts was achieved using Folin-Ciocalteau and AlCl) sub(3) reagents, respectively. The ethyl acetate extract of C. arvensis flowers was the most active in AChE inhibition assay (31.24 +/- 1.29%), while the n-hexane extract of C. officinalis leaves exerted the highest ferric ion-chelating capacity (74.27 +/- 2.25%). Thin layer chromatographic analysis indicated presence of flavonoid and triterpene derivatives mainly in the extracts.

Abstract  A new extraction and chromatographic procedure to quantify free and esterified ergosterol in tomato products was devised. The extraction solution was composed of a dichloromethane/methanol mixture in a 2:1 (v/v) ratio. This extraction solvent allowed for higher ergosterol recovery from tomato products (an average of 25% more) compared to hexane, which is frequently employed for ergosterol extraction. Both free and esterified ergosterol were determined by HPLC reverse-phase chromatography employing a Nova-Pall C-18 column (300 x 3.9 mm), filled with 4 mm average particle size and a guard column of the same material. The elution was performed at a now rate of I ml min-l with a linear gradient of solvent A (methanol/water, 80:20, v/v) and solvent B (dichloromethane). The gradient, starting at sample injection, was from 0 to 50% B for 20 min for the free ergosterol analysis and additional 15 min at 50% B to analyze the ergosterol esters. This technique has proven to be more sensitive for ergosterol determination than other reported chromatographic procedures. Moreover, ergosterol esters, extracted from various fungal sources, separated well and were easily quantified.

Abstract  Activated carbon of surface area 1100 m2/gm is impregnated with 4% sodium hydroxide plus 3% Cr(VI) as CrO3 with and without 5% ethylene diamine (EDA), 4% magnesium nitrate and 5% ruthenium chloride by using their aqueous solutions. These carbons are characterized for surface area analysis by BET conventional method and exposed to the vapours of sulphur mustard (HD) at room temperature (30 degrees C). After 24 h, the reaction products are extracted in dichloromethane and analyzed using gas chromatography and mass spectrometry (GC-MS). Hemisulphur mustard, thiodiglycol, 1,4-oxathiane are observed to be the products of reaction between sulphur mustard and NaOH/CrO3/C system, whereas on NaOH/CrO3/EDA/C system HD reacted to give 1,4-thiazane. On Mg(NO3)2/C system it gave hemisulphur mustard and thiodiglycol. On RuCl3/C system it degraded to divinyl sulphone. Residual sulphur mustard is observed along with reaction products in all systems studied. Reaction mechanisms are also proposed for these interesting surface reactions. Above-mentioned carbons can be used in filtration systems for protection against hazardous gases such as sulphur mustard.

Abstract  To determine the genotoxicity of river water towards mammalian cells, we applied Micronucleus in vitro test using mammalian cells to the samples taken from river Tamagawa located between Tokyo and Kanagawa prefecture. Water samples were condensed by Sep-pak cartridges and extracted by dichloromethane and methanol. Positive genotoxicity was observed in methanol extracts from sampling stations of Hinobashi and Marukobashi, while no dichloromethane extracts showed genotoxicity, suggesting that polar genotoxic micropollutants may be contained in the water of Tamagawa, at least in its down-stream. Significantly high mutagenicity also detected from Hinobashi and Marukobashi by Ames mutagenicity test using Salmonella Typhimurium, and some difference was obtained in sensitivity between the two methods. This may arise from the difference in species used, that is, mammalian cells in micronucleus test and bacteria in Ames mutagenicity test. (C) 1997 IAWQ. Published by Elsevier Science Ltd.

Abstract  The mutagenic potential of two soils amended with a municipal sewage sludge at two application rates was monitored over a 2-year period using Salmonella/microsome mutagenicity assay. Samples were collected from undisturbed monolith lysimeters of Weswood sandy clay (Fluventic Ustochrept) and Padina sandy loam (Grossarenic Paleustalf) amended with dried sewage sludge at 50 and 100 Mg/ha. Soil samples were collected and sequentially extracted with methylene chloride and methanol. The residues from these extracts were tested for mutagenicity at five doses with and without metabolic activation in Salmonella strain TA98. In general, the mutagenic potential of the amended soils of both application rate for the first 8 weeks following sludge application increased and then slowly decreased. The maximum mutagenic response observed in the soil extracts was 222 revertants at a dose of 10 mg of residue. This response was induced by the methanol extract from the Weswood soil collected 56 days after the application of 50 Mg/ha sewage sludge as compared to the 100 Mg/ha application which induced 202 revertants/mg. The mutagenicity of all fractions extracted from the sludge-amended soil at both application rates collected 717 days after application were not appreciably different from extracts from the unamended soils. The data indicate that chemicals that were mutagenic in bacteria persist in the soil and that at the higher application rates, as much as 2 years may be required for the mutagenic potential of the soil to return to background levels.

Abstract  Solubilities for 13 gases and vapours (CO2, alkanes from ethane to n-octane, benzene, toluene, xylene, dichloromethane, and methanol) in two Alberta bitumens (Athabasca and Wolf Lake) have been measured at several temperatures (30-150-degrees-C), using gas-liquid chromatography (GLC). The GLC method yields accurate solubilities and Henry's law constants for moderately soluble gases, but is not applicable to less soluble gases such as CH4 and H-2. Results have been used for calculations of DELTA-H(o) and DELTA-C(p)o for processes of the type Solute Substance (gas) reversible Solute Substance (in bitumen). Correlations of Henry's law constants and DELTA-H(o) values with carbon number for alkanes have been observed and used for predictions of CH4 solubilities in bitumens.

Abstract  An easy, sensitive, competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) for zearalenone in barley and Job's-tears was established. To improve sensitivity of the assay system for zearalenone, a solid phase antigen was prepared by affinity purification. This assay system uses a purified antigen and specific monoclonal antibodies for zearalenone. Consequently, the detection limit of zearalenone by CI-ELISA was increased to 0.2 ng/mL (equivalent to 10 ng/g in barley and Job's-tears). Zearalenone in barley and Job's-tears samples could be determined in the range of 25-1000 ng/g using method A (methanol-water and dichloromethane extraction) and method B (methanol-water alone) as sample preparation. The average recoveries of zearalenone from barley samples were observed to be 106% (mean CV, 10.3%) by method A and 98% (mean CV, 7.5%) by method B; also, those of zearalenone from Job's-tears samples were observed to be 96% (mean CV, 9.4%) by method A and 102% (mean CV, 6.5%) by method B. There was little or no difference between method A and method B for the recovery. For the benefit of a facile sample preparation, unknown amounts of zearalenone in barley and Job's-tears samples were assayed by method B. The results obtained by CI-ELISA were closely correlated with those of high-performance Liquid chromatography.

Abstract  Non-steady-state gas chromatography (NSGC) is a novel method for the determination of limiting activity coefficients of volatile solutes in volatile solvents. Both uncoated wide-bore fused-silica open tubular columns and columns packed only with deactivated solid support can be used. Solvent is injected and allowed to coat the walls or the solid support packing; while it evaporates and elutes from the column, small samples of solute are repetitively injected. Limiting activity coefficients are simply related to the decrease in solute retention time over the lifetime of the column and to the solvent and solute vapor pressures. Results are given for 10 alcohols and ketones in water solvent at 25-degrees-C; benzene, n-pentane, ethyl acetate, and 3 chloromethanes in methanol and ethanol solvents at 25-degrees-C; 17 polar and nonpolar compounds in 1-butanol and 1-pentanol solvents in the range 35-55-degrees-C; 8 polar and nonpolar solutes in toluene at 30 and 40-degrees-C; and n-pentane, dichloromethane, and methanol in CHCl3 solvent at 25-degrees-C. The average relative standard deviation is 6.4%. Agreement with activity coefficient data reported in the literature is satisfactory.

Abstract  A methanol extract from clove (Syzygium aromaticum) showed a suppressive effect of the SOS-inducing activity on the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) in the Salmonella typhimurium TA1535/pSK1002 umu test. The methanol extract was re-extracted with hexane, dichloromethane, ethyl acetate, butanol, and water. The hexane fraction showed a suppressive effect. Suppressive compounds in the hexane fraction were isolated by silica gel column chromatography and identified as trans-isoeugenol (1) and eugenol (2) by GC, GC-MS, IR, and (1)H and (13)C NMR spectroscopy. Compounds 1 and 2 suppressed the furylfuramide-induced SOS response in the umu test. Compounds 1 and 2 suppressed 42.3 and 29.9% of the SOS-inducing activity at a concentration of 0.60 micromol/mL. These compounds were assayed with other mutagens, 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). In addition, compounds 1 and 2 were assayed with aflatoxin B(1) (AfB(1)) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver metabolizing enzymes. These compounds showed suppressive effects of the SOS-inducing activity against furylfuramide, 4NQO, AfB(1), and Trp-P-1. To research the structure-activity relationship, methyl esters of 1 and 2 (1Me and 2Me) and o-eugenol (3), as compounds similar to 2, were also assayed with all mutagens. Compounds 1Me, 2Me, and 3 showed weak suppressive effects of the SOS-inducing activity against furylfuramide.

Abstract  Blends of commercial bisphenol-A-polycarbonate and styrene-acrylonitrile copolymers were prepared by precipitation in ethanol from the solution in methylene chloride in order to eliminate the low molecular weight substances contained in the commercial polymers, specially the oligomers contained in commercial SAN copolymers. Two glass transitions appear in the DSC thermograms of the blend at the same temperatures as in the pure components which, in principle, indicates that the blend consists of two phases formed by pure PC and pure SAN. In order to detect small changes in the glass transition process that could be indicative of different mobility of the polymer chains in the blend with respect to the pure polymers, blends of different compositions were subjected to different thermal treatments that included annealing at temperatures below both glass transitions, and then the DSC thermograms were recorded. A broadening in the peaks shown by the c(p)(T) curves measured on annealed samples in the zone of the PC transition is detected while no significant differences are shown by the glass transition of the SAN phase of the blend with respect to pure SAN copolymer. Dielectric relaxation experiments in the frequency domain (from 100 to 3.10(6)Hz) were carried out on the blends. The dielectric relaxation spectrum in the zone of the SAN main relaxation process was fitted with the stretched exponential equation showing no significant differences between the blends and the pure SAN copolymer. The region of the main relaxation process of PC was not analyzed due to the small polar activity of PC and the overlapping with the relaxation of the SAN phase.

Abstract  The methanol extract from Citrus aurantium showed a suppressive effect on umu gene expression of SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract from C. aurantium was successively re-extracted with hexane, dichloromethane, butanol, and water. A dichloromethane fraction showed a suppressive effect. The suppressive compounds in the dichloromethane fraction were isolated by SiO2 column chromatography and identified as tetra-O-methylscutellarein (1), sinensetin (2), and nobiletin (3) by EI-MS and H-1- and C-13 NMR spectroscopy. These compounds suppressed the furylfuramide-induced SOS response in the umu test. Gene expression was suppressed 67%, 45%, and 25% at a concentration of 0.6 mu mol/mL, respectively. The ID50 value (50% inhibition dose) of compound 1 was 0.19 mu mol/mL. These compounds were assayed with other mutagens, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which requires liver metabolizing enzymes, activated Trp-P-1, and UV irradiation. These compounds showed of all mutagen-induced SOS response in the umu test. In addition, compounds 1-3 exhibited antimutagenic activity in the S. typhimurium TA100 Ames test.

Abstract  Lack of data especially pertaining to the chemistry of mangrove wood species makes it difficult to prepare successful plans for their conservation and to use mangroves as a source of wood fiber. In this paper, chemical characterizations of the six main mangrove species of Bangladesh [namely Keora (Sonneratia apetala), Geoa (Excoecaria agallocha), Bine (Avicennia alba), Sundari (Heritiera fomes) Pashur (Xyloccarpous mekongests), and Kakra (Bruguiera gymnorhiza)] were investigated. The chemical results revealed that these species contain high percentages of dichloromethane followed by methanol extractives. Methanol extracts in Pashur, Sundari, and Bine were higher than 10%, which indicates high percentage of tannin material. The total lignin content in these species was higher than 25%, except for Gewa (23.6%) and Pashur (21.3%), which is higher than that of the normal range of hardwood. The pentosan content in these six species was within the range of 19.4-22.8%. The alpha-cellulose content in Keora and Gewa was acceptable for pulp production, but the others were lower than the normal range of hardwood. Alkaline nitrobenzene oxidation showed that all these species had a very high syringaldehyde to vanillin (2.6-5.0) ratio except Keora (1.6). Surprisingly, rhamnose is the main constituent with xylose of hemicelluloses of these six mangrove species. The ash content in these six mangrove wood species was also higher than that in normal hardwood.

Abstract  We have tested the effect of water, methanol and dichloromethane extracts from the leaves of several species of Impatiens (I. noli-tangere, I. parviflora, I. glandulifera) on germination of seeds Leucosinapis alba and Brassica napus. All of the tested extracts had inhibitory effects to seeds of all studied plants (except the dichloromethane extracts). The highest activity revealed methanol extract and extract from I. glandulifera.

Abstract  The tannery effluents at Kanpur (India) have been in use for irrigation since last many years, polluting soil directly while ground water and food crops indirectly. Gas chromatography-mass spectrometric analysis of the test samples revealed the presence of organic compounds including diisooctyl phthalate, phenyl N-methylcarbamate, dibutyl phthalate, bis 2-methoxyethyl phthalate, and higher alkanes. Tannery effluent extracts were prepared using XAD-4/8 resins, dichloromethane, chloroform, and hexane and tested with Ames Salmonella test and DNA repair-defective Escherichia coli K-12 mutants. In the presence of XAD-concentrated tannery effluent, TA98 found to be the most sensitive strain in terms of mutagenic index followed by TA97a whereas in terms of mutagenic potential TA102 was most responsive. The extracts were also found genotoxic as determined in terms of survival of E. coli K-12 mutants, suggesting the presence of DNA damaging compounds in the tannery effluents. In the light of results, precautious use of tannery effluents for irrigation is suggested.

Abstract  The brooded embryos and/or juveniles of the sea stars Neosmilaster georgianus (Studer, 1885) and Lysasterias perrieri (Studer, 1885) and the isopod Glyptonotus antarcticus (Eights, 1853) were examined for their acceptability using the sympatric sea star Odontaster validus (Koehler, 1906) as a predator. Organic extracts were prepared from embryos of both sea stars and juveniles of Lyasterias perrieri and Glyptonotus antarcticus and tested in alginate food pellets to confirm whether lack of acceptability was chemically based. We found both intact whole embryos and juveniles of the sea star Neosmilaster georgianus were not acceptable to Odontaster validus. A methanol extract of the embryos was palatable. This could be the result of either the sequestration of deterrent chemicals within embryos or the presence of noxious compounds that were not extractable in methanol. Embryos and juveniles of the sea star Lysasterias perrieri were not acceptable to sea stars. Food pellets containing methanol extracts of unacceptable embryos were deterrent against sea stars, suggesting a chemical defence. Juvenile brooded isopods (Glyptonotus antarcticus) were also found to be unacceptable in sea star feeding bioassays. Significant rejection of alginate pellets containing a lipophilic dichloromethane methanol extract of juveniles indicated that this lack of acceptability was chemically based. Our study provides further support for chemical defences in the offspring of brooding lecithotrophic Antarctic marine invertebrates.

Abstract  The determination of several compounds present in a commercial polycarbonate container intended to be used in microwave ovens which could be considered as potential migrants has been carried out by reversed-phase high-performance liquid chromatography (HPLC) with both ultraviolet (UV) and fluorescence detectors. Total dissolution with dichloromethane and polymer reprecipitation with methanol have been used to evaluate 100% potential migration as the worst case. The extract consisted of a complex mixture containing monomers, oligomers, UV stabilizers, antioxidants, degradation products, and other additives. Phenol, Bisphenol A, 2,4-di-tert-butylphenol, Cyasorb UV5411, bis(2-ethylhexylphthalate), Irganox 1076, and Irgafos 168 were identified by both retention times and fluorescence-to-UV ratios. Additional confirmation was achieved by HPLC with diode array detection and gas chromatography-mass spectrometry. Recovery percentages were in the range of 73.8-94.4%, the lowest one being for the antioxidant Irgafos 168 due to its transformation into the phosphate form and 2,4-di-tert-butylphenol. The concentrations of the studied analytes present in the polycarbonate container ranged between 0.9 and 240 microg.g(-)(1). The total dissolution conditions that may affect the final concentration of analytes, mainly Bisphenol A, are discussed.

Abstract  Paclitaxel was purified from cell cultures of Taxus chinensis by a combination of extraction, low-pressure chromatography, precipitation and HPLC. A crude extract (purity 6.9%) was obtained by methanol extraction of plant cell cultures, followed by liquid-liquid extraction using dichloromethane. The extract was purified to greater than 32% with a 97% step yield by low-pressure chromatography. After acetone/pentane precipitation, the resulting purity and step yield were 75.8% and 97.4%, respectively. High performance liquid chromatography steps, which were composed of an HPLC step with column-packed ODS and an HPLC step with column-packed silica, were applied to give over 99.5% purity with high yield. Amorphous paclitaxel with a fine particle size, which has a solubility advantage compared with the stable crystalline form, was obtained by dissolving in dichloromethane, followed by spray-drying. (C) 2004 Society of Chemical Industry.

Abstract  In a recent bench-scale study the vapor permeation-based removal of individual volatile organic compounds (VOCs), e.g. methanol, toluene from an N-2 stream was studied using microporous polypropylene hollow fibers having a plasma polymerized silicone coating on the outside surface of the fiber, The novel vapor permeation process employed bore-side feed flow and vacuum on the shell-side. The observed separation behavior was described successfully by an analytical solution of a simpler model and by a numerical solution of a more extensive set of model equations based on experimentally-determined behavior of concentration-dependent VOC permeance. The remarkably high separation performance achieved in that study on a bench-scale has led to pilot-plant studies using a larger module. Results of pilot-plant studies using streams containing high concentrations of VOCs, (e.g. 1-8% of methanal, and 0.3-1.3% of toluene) as well as low concentrations of VOCs (e.g. 0.1% or less of methanol, toluene, ethanol, iz-butanol, tetrahydrofuran, methylene chloride and acetone together) for a hollow fiber module containing 1000 fibers are reported here. The results for methanol removal from highly concentrated streams have been compared with the results obtained from simulations of theoretical models developed earlier. Model simulation results describe the observed pilot plant separation behavior well. These successes have prompted additional bench-scale laboratory studies with other VOCs (e.g. methylene chloride), results of which are also reported here; these results have also been compared with the predictions from the models developed earlier. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract  Accumulation of advanced glycation end products (AGEs) in vivo is associated with aging, diabetes, Alzheimer's disease, renal failure, etc. The objective of this study was to investigate the inhibitory effects of brown algae Fucus vesiculosus phlorotannins on the formation of AGEs. F. vesiculosus phlorotannins were extracted using 70% acetone. The resultant extract was fractionated into dichloromethane, ethyl acetate, butanol, and water fractions. The ethyl acetate fraction was further fractionated into four subfractions (Ethyl-F1 to -F4) using a Sephadex LH-20 column. F. vesiculosus acetone extract or fractions significantly inhibited the formation of AGEs mediated by glucose and methylglyoxal in a concentration-dependent manner. The concentrations of F. vesiculosus extracts required to inhibit 50% of albumin glycation (EC(50)) in the bovine serum albumin (BSA)-methylglyoxal assay were lower than those of aminoguanidine (a drug candidate for diabetic complication), except for F. vesiculosus acetone extract and dichloromethane fraction. In the BSA-glucose assay, F. vesiculosus extracts inhibited BSA glycation more than or as effectively as aminoguanidine, except for Ethyl-F3 and -F4. The ethyl acetate fraction and its four subfractions scavenged more than 50% of methylglyoxal in two hours. The hypothesis whether F. vesiculosus phlorotannins scavenged reactive carbonyls by forming adducts was tested. Phloroglucinol, the constituent unit of phlorotannins, reacted with glyoxal and methylglyoxal. Five phloroglucinol-carbonyl adducts were detected and tentatively identified using HPLC-ESI-MS(n).

Abstract  PLGA particles have been extensively used as a sustained drug-delivery system, but there are multiple drawbacks when delivering proteins. The focus of this work is to address the most significant disadvantages to the W/O/W double emulsion procedure and demonstrate that simple changes to this procedure can have significant changes to particle size and dispersity and considerable improvements to protein loading, activity and sustained active protein release. A systematic approach was taken to analyze the effects of the following variables: solvent miscibility (dichloromethane (DCM), ethyl acetate, acetone), homogenization speed (10 000-25 000 rpm), PLGA concentration (10-30 mg/ml) and additives in both the organic (sucrose acetate isobutyrate (SAIB)) and aqueous (bovine serum albumin (BSA)) phases. Increasing solvent miscibility decreased particle size, dispersity and protein denaturation, while maintaining adequate protein loading. Increasing solvent miscibility also lowered the impact of homogenization on particle size and dispersity and protein activity. Changes to PLGA concentration demonstrated a minimum impact on particle size and dispersity, but showed an inverse relationship between protein encapsulation efficiency and particle protein weight percent. Most particles tested provided sustained release of active protein over 60 days. Increasing solvent miscibility resulted in increases in the percent of active protein released. When subjected to synthesis conditions with DCM as the solvent, BSA as a stabilizer resulted in the maximum stabilization of protein at a concentration of 100 mg/ml. At this concentration, BSA allowed for increases in the total amount of active protein delivered for all three solvents. The benefit of SAIB was primarily increased protein loading.