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Sample records for octadecyl glyceryl ether-alpha

  1. Octadecyl ferulate behavior in 1,2-dioleoylphosphocholine liposomes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Octadecyl ferulate, a lipophilic derivative of ferulic acid having antioxidant properties, is found throughout the plant and fungi kingdoms. Octadecyl ferulate was prepared using solid acid catalyst, monitored using supercritical fluid chromatograph and purified to a 42% yield. Differential scanning...

  2. 21 CFR 172.811 - Glyceryl tristearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.811 Glyceryl tristearate. The food additive glyceryl tristearate may be safely used in food in accordance with the following prescribed conditions: (a) The food additive (CAS Reg. No. 555-43-1) is prepared...

  3. 21 CFR 184.1324 - Glyceryl monostearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Glyceryl monostearate. 184.1324 Section 184.1324 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1324 Glyceryl monostearate....

  4. 21 CFR 184.1323 - Glyceryl monooleate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... commerical oleic acid that is derived either from edible sources or from tall oil fatty acids meeting the...) and glyceryl esters of fatty acids present in commercial oleic acid. (b) The ingredient must be of...

  5. 21 CFR 184.1323 - Glyceryl monooleate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... esterification of commerical oleic acid that is derived either from edible sources or from tall oil fatty acids.... No. 25496-72-4) and glyceryl esters of fatty acids present in commercial oleic acid. (b)...

  6. Octadecyl ferulate behavior in 1,2-Dioleoylphosphocholine liposomes

    NASA Astrophysics Data System (ADS)

    Evans, Kervin O.; Compton, David L.; Whitman, Nathan A.; Laszlo, Joseph A.; Appell, Michael; Vermillion, Karl E.; Kim, Sanghoon

    2016-01-01

    Octadecyl ferulate was prepared using solid acid catalyst, monitored using Supercritical Fluid Chromatography and purified to a 42% yield. Differential scanning calorimetry measurements determined octadecyl ferulate to have melting/solidification phase transitions at 67 and 39 °C, respectively. AFM imaging shows that 5-mol% present in a lipid bilayer induced domains to form. Phase behavior measurements confirmed that octadecyl ferulate increased transition temperature of phospholipids. Fluorescence measurements demonstrated that octadecyl ferulate stabilized liposomes against leakage, maintained antioxidant capacity within liposomes, and oriented such that the feruloyl moiety remained in the hydrophilic region of the bilayer. Molecular modeling calculation indicated that antioxidant activity was mostly influenced by interactions within the bilayer.

  7. 21 CFR 184.1324 - Glyceryl monostearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Glyceryl monostearate. 184.1324 Section 184.1324 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  8. 21 CFR 184.1324 - Glyceryl monostearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Glyceryl monostearate. 184.1324 Section 184.1324 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  9. 21 CFR 184.1324 - Glyceryl monostearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glyceryl monostearate. 184.1324 Section 184.1324 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  10. 21 CFR 172.811 - Glyceryl tristearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Glyceryl tristearate. 172.811 Section 172.811 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.811...

  11. 21 CFR 172.811 - Glyceryl tristearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Glyceryl tristearate. 172.811 Section 172.811 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.811...

  12. 21 CFR 582.1324 - Glyceryl monostearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Glyceryl monostearate. 582.1324 Section 582.1324 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose...

  13. 21 CFR 582.1324 - Glyceryl monostearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Glyceryl monostearate. 582.1324 Section 582.1324 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose...

  14. 21 CFR 184.1323 - Glyceryl monooleate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... prepared by esterification of commerical oleic acid that is derived either from edible sources or from tall... (C21H40O4, CAS Reg. No. 25496-72-4) and glyceryl esters of fatty acids present in commercial oleic acid....

  15. 21 CFR 184.1323 - Glyceryl monooleate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... prepared by esterification of commerical oleic acid that is derived either from edible sources or from tall... (C21H40O4, CAS Reg. No. 25496-72-4) and glyceryl esters of fatty acids present in commercial oleic acid....

  16. 21 CFR 184.1328 - Glyceryl behenate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... glyceryl esters of behenic acid made from glycerin and behenic acid (a saturated C22 fatty acid). The... not more than 2.5 percent free fatty acids. (2) Behenic acid. Between 80 and 90 percent of the total fatty acid content. (3) Acid value. Not more than 4. (4) Saponification value. Between 145 and 165....

  17. 21 CFR 184.1328 - Glyceryl behenate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... glyceryl esters of behenic acid made from glycerin and behenic acid (a saturated C22 fatty acid). The... not more than 2.5 percent free fatty acids. (2) Behenic acid. Between 80 and 90 percent of the total fatty acid content. (3) Acid value. Not more than 4. (4) Saponification value. Between 145 and 165....

  18. 21 CFR 184.1328 - Glyceryl behenate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... glyceryl esters of behenic acid made from glycerin and behenic acid (a saturated C22 fatty acid). The... not more than 2.5 percent free fatty acids. (2) Behenic acid. Between 80 and 90 percent of the total fatty acid content. (3) Acid value. Not more than 4. (4) Saponification value. Between 145 and 165....

  19. 21 CFR 184.1328 - Glyceryl behenate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... glyceryl esters of behenic acid made from glycerin and behenic acid (a saturated C22 fatty acid). The... not more than 2.5 percent free fatty acids. (2) Behenic acid. Between 80 and 90 percent of the total fatty acid content. (3) Acid value. Not more than 4. (4) Saponification value. Between 145 and 165....

  20. 21 CFR 184.1323 - Glyceryl monooleate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... prepared by esterification of commerical oleic acid that is derived either from edible sources or from tall... (C21H40O4, CAS Reg. No. 25496-72-4) and glyceryl esters of fatty acids present in commercial oleic acid....

  1. Octadecyl ferulate behavior in 1,2-Dioleoylphosphocholine liposomes.

    PubMed

    Evans, Kervin O; Compton, David L; Whitman, Nathan A; Laszlo, Joseph A; Appell, Michael; Vermillion, Karl E; Kim, Sanghoon

    2016-01-15

    Octadecyl ferulate was prepared using solid acid catalyst, monitored using Supercritical Fluid Chromatography and purified to a 42% yield. Differential scanning calorimetry measurements determined octadecyl ferulate to have melting/solidification phase transitions at 67 and 39°C, respectively. AFM imaging shows that 5-mol% present in a lipid bilayer induced domains to form. Phase behavior measurements confirmed that octadecyl ferulate increased transition temperature of phospholipids. Fluorescence measurements demonstrated that octadecyl ferulate stabilized liposomes against leakage, maintained antioxidant capacity within liposomes, and oriented such that the feruloyl moiety remained in the hydrophilic region of the bilayer. Molecular modeling calculation indicated that antioxidant activity was mostly influenced by interactions within the bilayer. PMID:26332862

  2. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part II. Polymethacrylate-based monolithic column with "covalently" incorporated modified octadecyl fumed silica nanoparticles for reversed-phase chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    This study is concerned with the incorporation of surface modified fumed silica nanoparticles (FSNPs) into polymethacrylate based monolithic columns for use in reversed phase chromatography (RPC) of small solutes and proteins. First, FSNPs were modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPM) to yield the "hybrid" methacryloyl fumed silica nanoparticle (MFSNP) monomer. The resulting MFSNP was then mixed with glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent composed of cyclohexanol and dodecanol, and the in situ copolymerization of MFSNP, GMM and EDMA was performed in a stainless steel column of 4.6 mm i.d. The silanol groups of the hybrid monolith thus obtained were grafted with octadecyl ligands by perfusing the hybrid monolithic column with a solution of 4% w/v of dimethyloctadecylchlorosilane (DODCS) in toluene while the column was maintained at 110°C for 6h (in a heated HPLC oven). One of the originalities of this study was to demonstrate MFSNP as a novel derivatized "hybrid monomer" in making RPC monolithic columns with surface bound octadecyl ligands. In this respect, the RPC behavior of the monolithic column with "covalently" incorporated FNSPs having surface grafted octadecyl ligands was evaluated with alkylbenzenes, aniline derivatives and phenolic compounds. The results showed that the hybrid poly(GMA-EDMA-MFSNP) having surface bound octadecyl ligands exhibited hydrophobic interactions under reversed phase elution conditions. Furthermore, six standard proteins were baseline separated on the column using a 10min linear gradient elution at increasing ACN concentration in the mobile phase at a flow rate of 1.0mL/min using a 10 cm×4.6mm i.d. column. The relative standard deviations (RSDs) for the retention times of the tested solutes were lower than 2.1% and 2.4% under isocratic elution and gradient elution conditions, respectively. PMID:27059396

  3. Facile Preparation of Octadecyl Monoliths with Incorporated Carbon Nanotubes and Neutral Monoliths with Coated Carbon Nanotubes Stationary Phases for HPLC of Small and Large Molecules by Hydrophobic and π-π Interactions

    PubMed Central

    Mayadunne, Erandi; Rassi, Ziad El

    2014-01-01

    Two approaches for incorporating carbon nanotubes into monolithic columns for HPLC are described in this report. They pertain to the investigation of carbon nanotubes either (i) as entities to modulate solute retention on monolithic columns bearing well defined retentive ligands or (ii) as entities that constitute the stationary phase responsible for solute retention and separation. Approach (i) involved the incorporation of carbon nanotubes into octadecyl monolithic columns while approach (ii) concerns the preparation and evaluation of an ideal monolithic support and coating it with carbon nanotubes to yield a real “carbon nanotube stationary phase” for the HPLC separation of a wide range of solutes. First, an octadecyl monolithic column based on the in situ polymerization of octadecyl acrylate and trimethylolpropane trimethacrylate was optimized for use in HPLC separations of small and large solutes (e.g., proteins). To further modulate the retention and separation of proteins, small amounts of carbon nanotubes were incorporated into the octadecyl monolith column. In approach (ii), an inert, relatively polar monolith based on the in situ polymerization of glyceryl monomethacrylate (GMM) and ethylene glycol dimethacrylate (EDMA) proved to be the most suitable support for the preparation of “carbon nanotube stationary phase”. This carbon nanotube “coated” monolith proved useful in the HPLC separation of a wide range of small solutes including enantiomers. In approach (ii), a more homogeneous incorporation of carbon nanotubes into the diol monolithic columns (i.e., GMM/EDMA) was achieved when hydroxyl functionalized carbon nanotubes were incorporated into the GMM/EDMA monolithic support. In addition, high power sonication for a short time enhanced further the homogeneity of the monolith incorporated with nanotubes. In all cases, nonpolar and π interactions were responsible for solute retention on the monolith incorporated carbon nanotubes. PMID:25127634

  4. Facile preparation of octadecyl monoliths with incorporated carbon nanotubes and neutral monoliths with coated carbon nanotubes stationary phases for HPLC of small and large molecules by hydrophobic and π-π interactions.

    PubMed

    Mayadunne, Erandi; El Rassi, Ziad

    2014-11-01

    Two approaches for incorporating carbon nanotubes into monolithic columns for HPLC are described in this report. They pertain to the investigation of carbon nanotubes either (i) as entities to modulate solute retention on monolithic columns bearing well defined retentive ligands or (ii) as entities that constitute the stationary phase responsible for solute retention and separation. Approach (i) involved the incorporation of carbon nanotubes into octadecyl monolithic columns while approach (ii) concerns the preparation and evaluation of an ideal monolithic support and coating it with carbon nanotubes to yield a real "carbon nanotube stationary phase" for the HPLC separation of a wide range of solutes. First, an octadecyl monolithic column based on the in situ polymerization of octadecyl acrylate and trimethylolpropane trimethacrylate was optimized for use in HPLC separations of small and large solutes (e.g., proteins). To further modulate the retention and separation of proteins, small amounts of carbon nanotubes were incorporated into the octadecyl monolith column. In approach (ii), an inert, relatively polar monolith based on the in situ polymerization of glyceryl monomethacrylate (GMM) and ethylene glycol dimethacrylate (EDMA) proved to be the most suitable support for the preparation of "carbon nanotube stationary phase". This carbon nanotube "coated" monolith proved useful in the HPLC separation of a wide range of small solutes including enantiomers. In approach (ii), a more homogeneous incorporation of carbon nanotubes into the diol monolithic columns (i.e., GMM/EDMA) was achieved when hydroxyl functionalized carbon nanotubes were incorporated into the GMM/EDMA monolithic support. In addition, high power sonication for a short time enhanced further the homogeneity of the monolith incorporated with nanotubes. In all cases, nonpolar and π interactions were responsible for solute retention on the monolith incorporated carbon nanotubes. PMID:25127634

  5. Biodegradation of glyceryl trinitrate by Penicillium corylophilum Dierckx.

    PubMed Central

    Zhang, Y Z; Sundaram, S T; Sharma, A; Brodman, B W

    1997-01-01

    Penicillium corylophilum Dierckx, isolated from a contaminated water wet, double-base propellant, was able to completely degrade glyceryl trinitrate (GTN) in a buffered medium (pH 7.0) containing glucose and ammonium nitrate. In the presence of 12 mg of initial fungal inoculum, GTN (48.5 to 61.6 mumol) was quantitatively transformed in a stepwise process to glyceryl dinitrate (GDN) and glyceryl mononitrate (GMN) within 48 h followed by a decrease in the GDN content with a concomitant increase in the GMN level. GDN was totally transformed to GMN within 168 h, and the complete degradation of GMN was achieved within 336 h. The presence of glucose and ammonium nitrate in the growth medium was essential for completion of the degradation of GTN and its metabolites. Complete degradation of GTN by a fungal culture has not been previously reported in the literature. PMID:9143106

  6. A soft x-ray octadecyl hydrogen maleate crystal spectrograph

    SciTech Connect

    Fan, P.Z.; Fill, E.E.; Tietang, G.

    1996-03-01

    A crystal spectrograph is described which can be used to investigate laser-produced plasmas in the region of soft x rays at wavelengths of up to 60 A. The spectrograph uses an octadecyl hydrogen maleate crystal with a 2{ital d} of 63.5 A, combined with a very thin carbon filter (3000 A thick). As examples of its application, soft x-ray spectra in the range of 43{endash}51 A from laser plasmas of Si and Cu are presented. A spectral resolution of {lambda}/{Delta}{lambda}=1100 is deduced from the spectra. {copyright} {ital 1996 American Institute of Physics.}

  7. Formation of inclusion complexes between high amylose starch and octadecyl ferulate via steam jet cooking.

    PubMed

    Kenar, James A; Compton, David L; Little, Jeanette A; Peterson, Steve C

    2016-04-20

    Amylose-ligand inclusion complexes represent an interesting approach to deliver bioactive molecules. However, ferulic acid has been shown not to form single helical inclusion complexes with amylose from high amylose maize starch. To overcome this problem a lipophilic ferulic acid ester, octadecyl ferulate, was prepared and complexed with amylose via excess steam jet cooking. Jet-cooking octadecyl ferulate and high amylose starch gave an amylose-octadecyl ferulate inclusion complex in 51.0% isolated yield. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed that a 61 V-type inclusion complex was formed. Amylose and extraction assays showed the complex to be enriched in amylose (91.9±4.3%) and contain 70.6±5.6mgg(-1) octadecyl ferulate, although, minor hydrolysis (∼4%) of the octadecyl ferulate was observed under the excess steam jet-cooking conditions utilized. This study demonstrates that steam jet cooking is a rapid and scalable process in which to prepare amylose-octadecyl ferulate inclusion complexes. PMID:26876851

  8. 21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... § 172.852 Glyceryl-lacto esters of fatty acids. Glyceryl-lacto esters of fatty acids (the lactic acid... conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860 and/or oleic acid derived from tall oil fatty acids conforming with § 172.862 and/or edible fats...

  9. Effect of the nitric oxide donor, glyceryl trinitrate, on human gall bladder motility

    PubMed Central

    Greaves, R; Miller, J; O'Donnell, L; McLean, A; Farthing, M

    1998-01-01

    Background—Nitric oxide is a major neurotransmitter in non-adrenergic, non-cholinergic (NANC) pathways. NANC inhibitory innervation has been shown in human gall bladder muscle in vitro; the role of nitric oxide in human gall bladder emptying however is undefined.
Aims—To study the effect of glyceryl trinitrate, a nitric oxide donor, on gall bladder emptying in healthy subjects using a randomised, double blind, crossover, placebo controlled design.
Methods—Ultrasonographic gall bladder volume was measured in the fasting state in eight healthy volunteers after randomised administration of either glyceryl trinitrate 1200 µg buccal spray or placebo spray. On two further occasions, after randomised administration of either glyceryl trinitrate 1200 µg buccal spray or placebo spray, gall bladder volumes were also measured after a liquid test meal. 
Results—Glyceryl trinitrate significantly increased fasting gall bladder volume to a mean of 114% (SEM 5%) of pretreatment volume (p=0.039). Glyceryl trinitrate also significantly impaired gall bladder emptying between five and 40 minutes postprandially. Gall bladder ejection fraction was also reduced after glyceryl trinitrate compared with placebo (43 (6.9)% versus 68.4 (6.5)%, p=0.016).
Conclusions—This study shows that glyceryl trinitrate produces gall bladder dilatation in the fasting state and reduces postprandial gall bladder emptying, suggesting that nitric oxide mechanisms may be operative in the human gall bladder in vivo. 

 Keywords: gall bladder motility; nitric oxide; glyceryl trinitrate PMID:9577350

  10. Formation of inclusion complexes between high amylose starch and octadecyl ferulate via steam jet cooking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amylose can form inclusion complexes with guest molecules and represents an interesting approach to deliver bioactive molecules. However, ferulic acid has been shown not to form single helical inclusion complexes with amylose. To overcome this problem a ferulic acid ester, octadecyl ferulate, posses...

  11. 21 CFR 178.3505 - Glyceryl tri-(12-acetoxy-stearate).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... surface of calcium carbonate at a level not to exceed 1 weight-percent of the total mixture. (b) The calcium carbonate/glyceryl tri-(12-acetoxystearate) mixture is used as an adjuvant in polymers in...

  12. 21 CFR 178.3505 - Glyceryl tri-(12-acetoxy-stearate).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... surface of calcium carbonate at a level not to exceed 1 weight-percent of the total mixture. (b) The calcium carbonate/glyceryl tri-(12-acetoxystearate) mixture is used as an adjuvant in polymers in...

  13. Antifungal activity and isomerization of octadecyl p-coumarates from Ipomoea carnea subsp. fistulosa.

    PubMed

    Nidiry, Eugene Sebastian J; Ganeshan, Girija; Lokesha, Ankanahalli N

    2011-12-01

    Bioassay monitored HPLC assisted isolation and purification of the chief antifungal fraction of the leaves of Ipomoea carnea subsp. fistulosa (Convulvulaceae) were achieved using Colletotrichum gloeosporioides and Cladosporium cucumerinum as test organisms. The activity of the purified fraction was further confirmed by the dose dependent inhibition of the spore germination of Alternaria alternata and A. porri. The active fraction was identified as a mixture of (E)-octadecyl p-coumarate and (Z)-octadecyl p-coumarate. The two isomers were detected on an HPLC column with substantially different retention times, but once eluted from the column, one form was partly converted to the other in daylight. Conclusive evidence for the structures and their isomerization were obtained from the HPLC behavior, IR, UV, HRESIMS, CIMS and and NMR spectral data. Important 1H NMR and 13C NMR signals could be separately assigned for the isomers using 2D NMR techniques. PMID:22312731

  14. The stability of glyceryl trinitrate tablets during patient use.

    PubMed

    Marty, J; Shaw, J; Hunt, D

    1983-04-01

    The stability of glyceryl trinitrate (GTN) tablets stored in ways commonly used by patients was investigated to enable pharmacists and physicians to give better advice about tablet storage. Analysis of 43 samples of tablets collected from hospital patients showed that the GTN content of these samples differed significantly from that of fresh tablets. Tablets kept in the manufacturer's bottle contained significantly more GTN than those transferred to other airtight vials (p less than 0.05) or pill boxes (p less than 0.005). The content of GTN was also significantly lower in tablets stored in pill boxes compared with other vials (p less than 0.01). Similar trends were found when tablets were stored in glass or plastic vials, pill boxes or were left exposed to air in the laboratory. These results emphasize that the best way to store GTN tablets is in the manufacturer's container. However, since many patients find that this bottle is awkward and inconvenient, a suitable alternative would be to carry a few tablets in a small airtight container (preferably glass). The unused tablets should be discarded every two weeks and nothing else should be added to the container. The use of pill boxes should be strongly discouraged. PMID:6412672

  15. STUDY OF DUAL MATRIX TABLETS CONTAINING HYPROMELLOSE OF DIFFERENT VISCOSITY DEGREE AND GLYCERYL DIBEHENATE.

    PubMed

    Mužíková, Jitka; Holubová, Katerina; Komersová, Alena; Lochar, Václav

    2016-01-01

    Studies are described on the compressibility of directly compressible tableting materials containing two viscosity types of hypromellose in two concentrations and tableting materials containing additional glyceryl dibehenate, also in two concentrations. Compressibility is evaluated by means of the energy profile of the compression process and determination of tensile strength of tablets. Dissolution test examines the rate of release of the active ingredient from matrix tablets, which is subsequently evaluated mathematically. Increased concentrations of both hypromelloses and an addition of glyceryl dibehenate into tablets with both types of hypromellose improved compressibility. The rate of drug release was decreased with increasing viscosity degree of hypromellose and its increasing concentration. An addition of glyceryl dibehenate exerted the same influence on release as increased concentrations of the pertinent hypromellose. PMID:27180439

  16. Cardioprotective effects of glyceryl trinitrate: beyond vascular nitrate tolerance.

    PubMed

    Csont, Tamás; Ferdinandy, Péter

    2005-01-01

    Organic nitrates have been used for the treatment of ischemic heart diseases for more than 100 years and these drugs are still amongst the most frequently prescribed and applied drugs worldwide. Development of tolerance against the hemodynamic effects of nitrates during sustained therapy, however, limits their clinical application. Moreover, recent clinical studies have suggested that long-term nitrate treatment does not improve or may even worsen cardiovascular mortality, possibly due to the development of vascular nitrate tolerance. In agreement with these clinical findings, nitrate tolerance has been shown to increase superoxide and peroxynitrite production leading to vascular dysfunction. Nevertheless, nitrates exert a direct myocardial anti-ischemic effect that is independent from their vascular actions. The direct myocardial effect of glyceryl trinitrate (GTN) has been shown to be preserved even in the state of vascular nitrate tolerance. Moreover, no oxidative stress was observed in hearts isolated from rats with vascular nitrate tolerance, while increased systemic peroxynitrite formation was detected in the plasma in the same animals. The different effects of nitrates on the heart and vasculature are not well characterized; however, tissue specific differences in the metabolism and cellular signaling of nitrates might be a plausible explanation. These data suggest that sustained nitrate treatment increases oxidative stress in the extracardiac vasculature, thereby promoting the development of vascular nitrate tolerance. However, the direct myocardial anti-ischemic effect of nitrates seems to be preserved beyond the development of vascular nitrate tolerance. These new findings may open new perspectives in the clinical use of organic nitrates and suggest that the development of either cardioselective nitrates or nitrate-antioxidant hybrid drugs may replace classical nitrates in the therapy of ischemic heart disease. PMID:15626455

  17. Synthesis of octadecyl esters of histidine-containing tripeptides as potential regulators of plant growth

    SciTech Connect

    Ogrel, A.A.; Zvonkova, E.N.; Gafurov, R.G.

    1995-08-01

    Octadecyl esters of dipeptides and tripeptides of the type Phe-His, Val-His, Phe-Val-His and Val-Phe-His were synthesized using different methods. The minimum energy conformations of these peptides were calculated with computer minimization programs and compared with those of paclobutrazol, a well-known regulator of plant growth. It was demonstrated that the elongation of the peptide chain leads to a higher topochemical correspondence between paclobutrazol and the peptide derivatives than between paclobutrazol and amino acid derivatives. 9 refs., 2 figs., 3 tabs.

  18. Hemodynamic effect of avanafil and glyceryl trinitrate coadministration

    PubMed Central

    Swearingen, Dennis; Nehra, Ajay; Morelos, Susie; Peterson, Craig A

    2013-01-01

    A Phase I, double-blind, randomized, crossover study in healthy males (N=106) was conducted between March 21, 2004, and May 17, 2004, to determine the magnitude and duration of the hemodynamic interaction of avanafil (a phosphodiesterase type-5 inhibitor for treating males with erectile dysfunction) when coadministered with glyceryl trinitrate (NTG) compared with sildenafil and placebo. Subjects received avanafil (200 mg), sildenafil (100 mg), and placebo (on separate days) via the oral route followed by NTG (0.4 mg) 12, 8, 4, 1, or 0.5 hours post-dose via the sublingual route. Blood pressure (BP) and heart rate (HR) were assessed at defined intervals. Throughout the study (after administration of the study drug, and including the period after NTG administration), the effects of avanafil and sildenafil on BP and HR were significantly greatest overall, at the shortest (0.5-hour) time interval compared with placebo. By the 8- and 12-hour time intervals, no significant difference in BP or HR was observed for avanafil (8 and 12 hours) or sildenafil (12 hours) (p>0.05, compared with placebo). Compared with avanafil, sildenafil had a significantly greater effect when dosed 0.5 hours before NTG on standing HR (p=0.05); 1 hour before NTG on standing systolic blood pressure (SBP) (p<0.05), sitting SBP (p=0.01) and standing HR (p<0.01); and 12 hours before NTG on standing SBP (p=0.05). Throughout the study, symptomatic hypotension adverse events occurred in 27%, 29%, and 12%, and clinically significant reductions in standing SBP (≥30 mmHg) occurred in 15%, 29%, and 12% of subjects dosed with avanafil, sildenafil, and placebo, respectively (overall treatment differences: p<0.01 and p<0.05, respectively). These data show that avanafil and sildenafil have no significant effect on BP and HR if administered to healthy males ≥8 hours (avanafil) or ≥12 hours (sildenafil) before a sublingual dose of NTG. However, results may differ in populations with known vascular disease

  19. Final report on the safety assessment of trilaurin, triarachidin, tribehenin, tricaprin, tricaprylin, trierucin, triheptanoin, triheptylundecanoin, triisononanoin, triisopalmitin, triisostearin, trilinolein, trimyristin, trioctanoin, triolein, tripalmitin, tripalmitolein, triricinolein, tristearin, triundecanoin, glyceryl triacetyl hydroxystearate, glyceryl triacetyl ricinoleate, and glyceryl stearate diacetate.

    PubMed

    Johnson, W

    2001-01-01

    Triesters of glycerin and aliphatic acids, known generically as glyceryl triesters and specifically as Trilaurin, etc., are used in cosmetic products as occlusive skin-conditioning agents and/or nonaqueous viscosity-increasing agents. Hundreds of glyceryl triesters are used in a wide variety of cosmetic products at concentrations ranging from a few tenths of a percent to 46%. Glyceryl triesters are also known as triglycerides; ingested triglycerides are metabolized to monoglycerides, free fatty acids, and glycerol, all of which are absorbed in the intestinal mucosa and undergo further metabolism. Dermal absorption of Triolein in mice was nil; the oil remained at the application site. Only slight absorption was seen in guinea pig skin. Tricaprylin and other glyceryl triesters have been shown to increase the skin penetration of drugs. Little or no acute, subchronic, or chronic oral toxicity was seen in animal studies unless levels approached a significant percentage of caloric intake. Subcutaneous injections of Tricaprylin in rats over a period of 5 weeks caused a granulomatous reaction characterized by oil deposits surrounded by macrophages. Dermal application was not associated with significant irritation in rabbit skin. Ocular exposures were, at most, mildly irritating to rabbit eyes. No evidence of sensitization or photosensitization was seen in a guinea pig maximization test. Most of the genotoxicity test systems were negative. Tricaprylin, Trioctanoin, and Triolein have historically been used as vehicles in carcinogenicity testing of other chemicals. In one study, subcutaneous injection of Tricaprylin in newborn mice produced more tumors in lymphoid tissue than were seen in untreated animals, whereas neither subcutaneous or intraperitoneal injection in 4- to 6-week-old female mice produced any tumors in another study. Trioctanoin injected subcutaneously in hamsters produced no tumors. Trioctanoin injected intraperitoneally in pregnant rats was associated with

  20. Prostaglandin E2-Glyceryl Ester: In Vivo Evidence for a Distinct Pharmacological Identity from Intraocular Pressure Studies.

    PubMed

    Woodward, David F; Poloso, Neil J; Wang, Jenny W

    2016-08-01

    Prostaglandin E2 (PGE2)-2-glyceryl ester is a cyclo-oxygenase 2 product of the endocannabinoid 2-arachidonyl glycerol. It is claimed as pharmacologically novel, but this is complicated by rapid and irreversible isomerization to the 1(3) ester. For ocular studies, enzymatic hydrolysis of the ester moiety creates an additional complication. PG-glyceryl esters were stabilized to isomerization and hydrolysis by replacing the noncarbonyl O with NH, to form the serinolamide and propanediolamide as stable analogs of PG-2-glyceryl and PG-2-1(3) glyceryl esters, respectively. Intraocular pressure was measured in conscious dogs and conscious laser-induced ocular hypertensive monkeys. Pharmacological studies involved stable transfectants for each of the human recombinant prostanoid receptors and the isolated feline iris for prostamide activity. PGE2-serinolamide and PGE2- propanediolamide were essentially inactive at all receptors except the EP3 receptor (EC50, ∼500 nM). This obliged elucidation of EP3 receptor involvement in the intraocular pressure response to these PGE2-glycyerl ester analogs. Since the EP3 receptor agonists sulprostone and GR 63799 did not lower monkey intraocular pressure, a role for EP3 receptors in mediating the effects of PGE2-serinolamide and PGE2-propanediolamide is not indicated. PGE2-glyceryl ester (0.01% and 0.1%) substantially lowered intraocular pressure in monkeys. PGE2-propanediolamide was more efficacious than PGE2-serinolamide in lowering intraocular pressure in monkey eyes, but both appeared equieffective in dog eyes. PGE2-serinolamide dose-dependently (0.01- 0.1%) lowered intraocular pressure in both species, but PGF2 α-serinolamide was inactive. In conclusion, stable PGE2-glyceryl ester analogs lowered intraocular pressure. These findings are consistent with the presence of a PGE2-glyceryl ester-specific recognition site in the eye. PMID:27217589

  1. Targeted therapy of colorectal neoplasia with rapamycin in peptide-labeled pegylated octadecyl lithocholate micelles.

    PubMed

    Khondee, Supang; Rabinsky, Emily F; Owens, Scott R; Joshi, Bishnu P; Qiu, Zhen; Duan, Xiyu; Zhao, Lili; Wang, Thomas D

    2015-02-10

    Many powerful drugs have limited clinical utility because of poor water solubility and high systemic toxicity. Here, we formulated a targeted nanomedicine, rapamycin encapsulated in pegylated octadecyl lithocholate micelles labeled with a new ligand for colorectal neoplasia, LTTHYKL peptide. CPC;Apc mice that spontaneously develop colonic adenomas were treated with free rapamycin, plain rapamycin micelles, and peptide-labeled rapamycin micelles via intraperitoneal injection for 35days. Endoscopy was performed to monitor adenoma regression in vivo. We observed complete adenoma regression at the end of therapy. The mean regression rate for peptide-labeled rapamycin micelles was significantly greater than that for plain rapamycin micelles, P<0.01. On immunohistochemistry, we observed a significant reduction in phospho-S6 but not β-catenin expression and reduced tumor cell proliferation, suggesting greater inhibition of downstream mTOR signaling. We observed significantly reduced renal toxicity for peptide-labeled rapamycin micelles compared to that of free drug, and no other toxicities were found on chemistries. Together, this unique targeted micelle represents a potential therapeutic for colorectal neoplasia with comparable therapeutic efficacy to rapamycin free drug and significantly less systemic toxicity. PMID:25483425

  2. Water-developable resists based on glyceryl methacrylate for 193-nm lithography

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Baek; Jang, Ji-Hyun; Choi, Jae-Hak; Lee, Kwan-Ku; Ko, Jong-Sung

    2004-05-01

    Novel water-developable negative resists were designed to induce both cross-linking and polarity change upon exposure and bake. The matrix polymers were synthesized by copolymerization of glyceryl methacrylate and methacrolein. The acid-catalyzed acetalization of the polymer induced cross-linking, polarity change, and increase in dry-etch resistance. The resist formulated with this polymer and cast in a water-ethanol mixture, showed 0.7 μm line and space patterns using a mercury-xenone lamp in a contact printing mode and pure water as a developer.

  3. A novel glyceryl monoolein-bearing cubosomes for gambogenic acid: Preparation, cytotoxicity and intracellular uptake.

    PubMed

    Luo, Qing; Lin, Tongyuan; Zhang, Cai Yuan; Zhu, Tingting; Wang, Lei; Ji, Zhaojie; Jia, Buyun; Ge, Tao; Peng, Daiyin; Chen, Weidong

    2015-09-30

    Lyotropic cubic liquid crystalline nanoparticles, also known as 'cubosomes', have been tested as effective carriers for a variety of drugs due to their ability to enhance delivery efficiency and reduced drug side effects. Cubosomes are colloidal carriers composed of biodegradable Glyceryl monooleate and F127. Being composed of well tolerable and physiological materials, these carriers are well tolerated, compatible and non-toxic. In this study, therefore, we developed a novel, water-soluble, glyceryl monooleate and F127 based multiblock copolymer for Gambogenic acid (GNA) by emulsion-evaporation and low temperature-solidification technique. Physicochemical properties, in vitro cytotoxicity, cellular uptake and in vivo pharmacokinetic of GNA-loaded cubosomes (GNA-Cubs) were investigated. The results revealed that GNA-Cubs were spherical or ellipsoidal monocellular by dynamic light scattering, meanwhile, 150-250nm in mean size with narrow polydispersity indexas determined by transmission electron microscopy. Small angle X-ray scattering indicated that GNA-Cubs retain the Pn3m cubic symmetry. Compared with GNA solution, GNA-Cubs exhibited markedly prolonged inhibitory activity in SMMC-7721 cells, as well as time-dependent increases in intra-cellular uptake. Furthermore, in vivo pharmacokinetic study showed that the Cmax values and the AUC of GNA-Cubs were higher than GNA solution approximately 1.2-fold and 9.1-fold, respectively. In conclusion, the results showed that the cubic liquid crystalline nanoparticles could be a potentially nanocarrier in the delivery of GNA for cancer therapy. PMID:26209071

  4. Identification of halogen atoms in scanning tunneling microscopy images of substituted phenyl octadecyl ethers.

    PubMed

    Lee, H S; Iyengar, S; Musselman, I H

    2001-11-15

    A homologous series of para-substituted phenyl octadecyl ethers (X-POEs, where X = H, Cl, Br, I) was prepared using the Williamson ether synthesis and characterized by 1H NMR and GC/MS. Scanning tunneling microscopy images acquired from these ethers revealed a bias-dependent contrast corresponding to electron density contours of various X-POE molecular orbitals. Images reflecting the electron density contour of the highest occupied molecular orbital exhibited four bright spots--one for the halogen atom, two representing the pair of lobes of the phenyl ring, and one for the oxygen/alpha-carbon atoms. For each X-POE, the intensities (Zmax) of the spots for the halogen atom and the lobe of the phenyl ring closest to the halogen were measured and their ratio was calculated (Cl-POE 0.49 +/- 0.06; Br-POE 0.59 +/- 0.06; I-POE 0.75 +/- 0.07). Analysis of variance at the 95% confidence level revealed that the intensity ratios were consistent from molecule to molecule, image to image, and day to day. According to the Student t-test, the average Zmax ratios for Cl-POE, Br-POE, and I-POE are different at the 95% confidence level. In addition, they follow a trend that corresponds favorably with that of the atomic radii of the halogens. The probability of classifying a single X-POE molecule as Cl-POE, Br-POE, or I-POE is variable and depends on the magnitude of the Zmax ratio. PMID:11816584

  5. Influence of glyceryl trinitrate and nifedipine on coronary sinus blood flow and global myocardial metabolism during coronary artery operation.

    PubMed

    van Wezel, H B; Bovill, J G; Koolen, J J; Patrick, M R; Fiolet, J W; van der Stroom, J G

    1986-09-01

    The effects of intravenous infusions of glyceryl trinitrate and nifedipine on systemic haemodynamic function, coronary haemodynamic function, and global myocardial metabolism were compared in two groups of eleven patients with unimpaired left ventricular function undergoing elective coronary artery operation who were anaesthetised with high dose fentanyl. Severe post-sternotomy hypertension developed in three patients in the glyceryl trinitrate group who were resistant to the hypotensive effect of this agent. All patients given nifedipine remained haemodynamically stable. Coronary sinus blood flow and myocardial oxygen consumption increased and coronary vascular resistance decreased after sternotomy in the nifedipine group but not in the glyceryl trinitrate group. There is no satisfactory explanation for the apparently paradoxical increase in myocardial oxygen consumption in the patients given nifedipine. This phenomenon did not appear to be associated with any detrimental effect of left ventricular function. Thus nifedipine was better than glyceryl trinitrate for the control of post-sternotomy hypertension in patients with good left ventricular function. Intravenous nifedipine is not recommended, however, for the intraoperative control of blood pressure in patients with unstable angina or impaired left ventricular function. PMID:3092847

  6. Time-dependent inhibition by glyceryl trinitrate of platelet aggregation caused by U46619 (a thromboxane/endoperoxide receptor agonist).

    PubMed

    Kampf, G; Ritter, J M

    1994-07-01

    Glyceryl trinitrate is a weak inhibitor of platelet aggregation in vitro. Its effect on platelet aggregation in response to U46619 (a thromboxane/endoperoxide receptor agonist) was studied turbidometrically in platelet-rich plasma from healthy volunteers. The object was to determine whether inhibition was influenced by a period of preincubation between preparation of platelet-rich plasma and addition of glyceryl trinitrate. Incubation was performed at 37 degrees C and 22 degrees C. Samples were removed at intervals and transferred to an aggregometer cuvette at 37 degrees C. Glyceryl trinitrate (100 microM) or an equal volume of distilled water was added 5 min before U46619 (2 microM), and aggregation recorded as change in light transmission. Inhibition by glyceryl trinitrate was markedly time and temperature dependent, with a progressive increase in inhibitory potency between 120 and 300 min preincubation at 37 degrees C but not at 22 degrees C. The explanation of this is unknown but the effect was not influenced by lipopolysaccharide or by cycloheximide, so it does not appear to be due to exposure to endotoxin or to enzyme induction in vitro. PMID:7946941

  7. Biotransformation of glyceryl trinitrate (GTN) in isolated bovine pulmonary artery (BPA) and bovine pulmonary vein (BPV)

    SciTech Connect

    Not Available

    1986-03-01

    A proposed mechanism of GTN-induced vasodilation requires biotransformation of GTN to glyceryl dinitrate (GDN). They have previously shown that GTN is metabolized to GDN during relaxation of isolated rabbit aorta. The authors have extended this study to include BPA and BPV and to determine if their sensitivity to GTN correlates with their ability to metabolize GTN. Strips of BPA and BPV were contracted submaximally with KCl and then incubated with 0.5 ..mu..M /sup 14/C-GTN for 2 min. GTN-induced relaxation of these vessels was monitored and tissue GTN and metabolite concentrations were measured. Data are presented which support the above hypothesis that GTN biotransformation and relaxation occur together in vascular smooth muscle; however, there appear to be factors other than extent of GTN biotransformation that account for the difference in sensitivity to GTN of the artery and vein.

  8. Codelivery of paclitaxel and small interfering RNA by octadecyl quaternized carboxymethyl chitosan-modified cationic liposome for combined cancer therapy.

    PubMed

    Zhang, Ran; Wang, Shi-Bin; Chen, Ai-Zheng; Chen, Wei-Guang; Liu, Yuan-Gang; Wu, Wen-Guo; Kang, Yong-Qiang; Ye, Shi-Fu

    2015-09-01

    Conventional therapeutic approaches for cancer are limited by cancer cell resistance, which has impeded their clinical applications. The main goal of this work was to investigate the combined antitumor effect of paclitaxel with small interfering RNA modified by cationic liposome formed from modified octadecyl quaternized carboxymethyl chitosan. The cationic liposome was composed of 3β-[N-(N', N'-dimethylaminoethane)-carbamoyl]-cholesterol, dioleoylphosphatidylethanolamine, and octadecyl quaternized carboxymethyl chitosan. The cationic liposome properties were characterized by Fourier transform infrared spectroscopy, dynamic light scattering and zeta potential measurements, transmission electron microscopy, atomic force microscopy, and gel retardation assay. The cationic liposome exhibited good properties, such as a small particle size, a narrow particle size distribution, a good spherical shape, a smooth surface, and a good binding ability with small interfering RNA. Most importantly, when combined with paclitaxel and small interfering RNA, the composite cationic liposome induced a great enhancement in the antitumor activity, which showed a significantly higher in vitro cytotoxicity in Bcap-37 cells than liposomal paclitaxel or small interfering RNA alone. In conclusion, the results indicate that cationic liposome could be further developed as a codelivery system for chemotherapy drugs and therapeutic small interfering RNAs. PMID:25838353

  9. Transdermal glyceryl trinitrate (nitroglycerin) in healthy persons: acute effects on skin temperature and hemodynamic orthostatic response.

    PubMed

    Haebisch, E M

    1995-01-01

    In order to find an explanation for individual reactions to transdermal glyceryl trinitrate (GTN) we studied the skin temperature and hemodynamic reactions in 63 healthy persons. The data were obtained before and after the application of GTN and Glycerin (GL) placebo patches, during one hour. The skin temperature was measured on both forearms, the local (left sided) and systemic (right sided) reaction on GTN was related to the skin fold and the calculated body fat content. The bilateral rise of skin temperature and its duration was higher and longer in obese than in lean persons mainly in obese women. The UV induced thermo and the later photothermoreaction (Erythema) was reduced on the left forearm after the application of GTN and GL patches. The observed hemodynamic GTN effect confirmed known postural reactions, such as decreased arterial pressure (delta mAP = -2.9%), increased heart rate (delta HR = +7.4%) and QTc prolongation (delta QTc = +4.9%) in upright position. An adverse drug effect with increased mean blood pressure (delta mAP = +12%) and increased heart rate (delta HR = +10.4%) mainly in supine position was observed in 11% of the participants, but only in men. Such a reaction was already described by Murell, 1879. Individual GTN effects were analyzed and related to habits and family history. In male smokers and in persons with hypertensive and diabetic close relatives, the hypotensive GTN effect was accentuated in supine position. In the upright position the group with hypertensives in the family presented a moderate hypotensive reaction without secondary tachycardia and the smokers presented only a slightly increased heart rate. Our observations suggest that individual reactions to transdermal glyceryl trinitrate (GTN) with its active component nitric oxide (NO) depends on physiological conditions, related to endogenous vasoactive substances, mainly the interaction with EDRF (the endogenous NO) and the activity of the Renin-Angiotensin System. PMID

  10. Biotransformation of glyceryl trinitrate occurs concurrently with relaxation of rabbit aorta

    SciTech Connect

    Brien, J.F.; McLaughlin, B.E.; Breedon, T.H.; Bennett, B.M.; Nakatsu, K.; Marks, G.S.

    1986-05-01

    This study was conducted to test the hypothesis that biotransformation of glyceryl trinitrate (GTN) is involved in GTN-induced relaxation of vascular smooth muscle. Isolated rabbit aortic strips (RAS) were contracted submaximally with phenylephrine (PE) and then were incubated with 0.5 microM (/sup 14/C)GTN in a time course study. GTN-induced relaxation (inhibition of PE-induced tone) of RAS was monitored and tissue GTN and glyceryl-1,2- and 1,3-dinitrate (GDN) concentrations were measured by thin-layer chromatography and liquid scintillation spectrometry at 0.5, 1, 2 and 20 min after incubation. Biotransformation of GTN to GDN occurred during GTN-induced relaxation of RAS. The tissue GDN concentration was dependent on the time duration of incubation with GTN and was related to the magnitude of GTN-induced tissue relaxation. At the 20-min interval, the GDN concentration in the incubation medium indicated appreciable efflux of GDN metabolites from the RAS. In the biotransformation of GTN by RAS, there was about 4-fold preferential formation of 1,2-GDN compared with 1,3-GDN. RAS were made tolerant to GTN in vitro by incubation with 500 microM GTN for 1 hr. After washing, GTN-tolerant and nontolerant (incubation with vehicle for 1 hr) RAS were contracted submaximally with PE, and then were incubated with 0.5 microM (/sup 14/C)GTN for 2 min. GTN-induced relaxation of RAS and tissue GDN concentration were significantly less for GTN-tolerant tissue compared with nontolerant tissue. Tissue GTN concentration was similar for both GTN-tolerant and nontolerant RAS, which indicated that the tissue uptake of GTN was similar and that GTN biotransformation was diminished in tolerant tissue.(ABST

  11. The use of octadecyl-bonded microparticulate silica in the separation of free and bound fractions during saturation analysis of vitamin D metabolites.

    PubMed

    Coldwell, R D; Nolan, J; Trafford, D J; Mawer, E B; Makin, H L

    1992-09-01

    The use of octadecyl-bonded microparticulate silica to separate free and bound fractions during the saturation analysis of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D has been investigated. A slurry of octadecyl-bonded silica in an appropriate incubation buffer was prepared and used in parallel with a conventional dextran-coated charcoal suspension in several assay procedures. Standard curves, non-specific binding and plasma values were compared. A competitive protein binding assay for 25-hydroxyvitamin D and two radioreceptor assays and one radioimmunoassay for 1,25-dihydroxyvitamin D were investigated. In most cases the octadecyl-bonded silica preparation gave the more favourable results; its action was rapid, time- and temperature-independent, and it produced low non-specific binding and higher B0 values in all the assays examined. It was in our hands easier to use than dextran-coated charcoal. The use of octadecyl-bonded silica is recommended as an efficient agent for the separation of free and bound fractions in the saturation analysis of vitamin D metabolites. PMID:1283701

  12. Avoidance of tolerance and lack of rebound with intermittent dose titrated transdermal glyceryl trinitrate. The Transdermal Nitrate Investigators.

    PubMed Central

    Fox, K M; Dargie, H J; Deanfield, J; Maseri, A

    1991-01-01

    OBJECTIVES--To investigate the efficacy of transdermal glyceryl trinitrate given continuously and with a nocturnal nitrate free period. DESIGN--Double blind placebo controlled study with two parallel limbs. SETTING--Multicentre trial. PATIENTS--52 patients randomised to receive either continuous treatment (23 patients) or intermittent treatment with an individually titrated dose (29 patients) for 14 days: both treatments were compared with placebo in a cross-over fashion. INTERVENTION--Continuous treatment with 10 mg per 24 hours of transdermal glyceryl trinitrate or intermittent transdermal glyceryl trinitrate titrated to give an arbitrary 10 mm Hg drop in systolic blood pressure (mean dose 18.2 mg) given over approximately 16 hours. MAIN OUTCOME MEASURE--Treadmill exercise stress testing and ambulatory monitoring of the ST segment after 14 days' treatment. RESULTS--After 14 days' intermittent treatment resting supine and standing systolic blood pressure fell by 7.5 mm Hg (95% confidence interval 2.7 to 12.2) and 9.0 mm Hg (95% CI 3.4 to 14.5) respectively (p less than 0.01); resting heart rate was unchanged. Mean heart rate at 1 mm ST segment depression rose by 11.9 beats/min (CI 1.1 to 23.7) (p less than 0.05), mean time to onset of angina increased by 59 seconds (CI 10.8 to 108) (p less than 0.05), and total exercise duration increased by 40 seconds (p less than 0.05). These changes were not seen after continuous treatment. The frequency of ischaemic episodes was not reduced with either regimen nor was the circadian distribution of these episodes altered, in particular nocturnal episodes did not increase during intermittent treatment. CONCLUSION--Tolerance to glyceryl trinitrate was avoided by the use of individually titrated doses administered with a nocturnal nitrate free period. There was no evidence of "rebound" on ambulatory monitoring during this treatment. PMID:1909152

  13. Lack of rebound during intermittent transdermal treatment with glyceryl trinitrate in patients with stable angina on background beta blocker.

    PubMed Central

    Holdright, D R; Katz, R J; Wright, C A; Sparrow, J L; Sullivan, A K; Cunningham, A D; Fox, K M

    1993-01-01

    OBJECTIVE--To assess whether intermittent transdermal treatment with glyceryl trinitrate causes clinically significant rebound in patients maintained on beta blockers for stable angina pectoris. DESIGN--Serial treadmill exercise testing in a double blind, randomised, placebo controlled cross over trial. Baseline exercise testing was performed at 0900 and 1100 at visit 1. Transdermal glyceryl trinitrate patches releasing 15 mg/24 h were applied at 2200 the evening before visits 2 and 3, and exercise testing was performed at 0900 the next morning. The patch was removed and replaced with either an identical patch or matching placebo and exercise tests were repeated two hours later. The alternative treatment was given at visit 3. SETTING--Tertiary referral centre. PATIENTS--14 patients with stable angina pectoris maintained on beta blocker treatment alone. MAIN OUTCOME MEASURES--Time to angina, 1 mm ST segment depression, and total time, together with heart rate, systolic blood pressure, and rate-pressure product. RESULTS--Active treatment improved treadmill performance at 0900 and 1100. Time to angina, time to 1 mm ST segment depression, and total time fell significantly on placebo compared with the 0900 exercise test on active treatment, but were not significantly different to the baseline exercise test either. CONCLUSIONS--Intermittent transdermal treatment with glyceryl trinitrate is not associated with the rebound phenomenon in patients maintained on beta blockers for stable angina pectoris. PMID:8096389

  14. A common pathway of nitric oxide release from AZD3582 and glyceryl trinitrate.

    PubMed

    Berndt, Georg; Grosser, Nina; Hoogstraate, Janet; Schröder, Henning

    2004-02-01

    4-(Nitrooxy)-butyl-(S)-2-(6-methoxy-2-naphthyl)-propanoate (AZD3582) is a cyclooxygenase (COX)-inhibiting nitric oxide donator (CINOD). It donates nitric oxide (NO) in biological systems through as yet unidentified mechanisms. cGMP, a marker of intracellularly generated NO, was increased up to 27-fold over basal levels by AZD3582 (1-30microM) in LLC-PK1 kidney epithelial cells. A 5h pretreatment with glyceryl tinitrate (GTN, 0.1-1microM) attenuated the cGMP response to a subsequent challenge with AZD3582 or GTN. Similarly, AZD3582 (10-30microM) pretreatment reduced the increase in cGMP on subsequent incubation with AZD3582 or GTN. In contrast, cGMP stimulation by SIN-1, which releases NO independently of enzymatic catalysis, remained unimpaired in cells pretreated with GTN or AZD3582. Our results demonstrate that AZD3582 decreases the sensitivity of the guanylyl cyclase/cGMP system to GTN and vice versa. This suggests that bioactivation pathways for organic nitrates, which involve enzymatic catalysis, may be responsible for NO donation from AZD3582. PMID:14757506

  15. Sublingual glyceryl trinitrate and the peripheral thermal responses in normal and cold-sensitive individuals.

    PubMed

    Hope, Katrina; Eglin, Clare; Golden, Frank; Tipton, Mike

    2014-01-01

    Non-freezing cold injury (NFCI) is a prevalent, but largely undiagnosed and poorly understood syndrome afflicting many who, as part of their work or leisure, expose their extremities to cold temperatures. The long term sequelae of NFCI are hyperhidrosis, cold-sensitivity and pain; these can last a lifetime. We tested the hypothesis that, in comparison with a placebo, sublingual glyceryl trinitrate (GTN) would increase the peripheral microcirculation during and after a mild cold challenge of individuals who had not been diagnosed with NFCI, but were cold-sensitive. Naive participants were categorised into two cohort groups: control (n=7) or cold-sensitive (n=6). All participants undertook a standardised two minute cold exposure of their right foot while toe skin temperature (Tsk; infra-red thermograms) and blood flow (toe pad laser Doppler) were measured. GTN increased the rate of rewarming and absolute Tsk of the coldest toe after the cold challenge in cold-sensitive individuals. GTN also increased the blood flow in the great toe during rewarming in some cold-sensitive individuals. We accept our hypothesis and suggest that the impairment in the vasodilatory response seen in individuals with cold-sensitivity can be overcome by the use of GTN, an endothelial-independent NO donor, and thereby improve the rewarming of cooled peripheral tissues. PMID:24280630

  16. [Effects of nitrogen oxide donor glyceryl trinitrate on pressure pain threshold in humans].

    PubMed

    Thomsen, L L; Brennum, J; Iversen, H K; Olesen, J

    1997-07-21

    The purpose of the present study was to examine the effect of the nitric oxide (NO) donor glyceryl trinitrate (GTN) on nociceptive thresholds in man. On two different study days twelve healthy subjects received a stair case infusion of GTN (0.015, 0.25, 1.0, 2.0 micrograms/kg/min 20 min each dose) or placebo in a randomized double-blind cross-over design. Before the infusion and after 15 min of infusion on each dose, pressure pain detection- and tolerance thresholds were determined by pressure algometry in three different anatomic regions (finger, a temporal region with interposed myofascial tissue and a temporal region without interposed myofascial tissue). Relative to placebo the three higher GTN doses induced a decrease in both detection- and tolerance-thresholds in the temporal region with interposed myofascial tissue. No such changes were observed in the two other stimulated regions. These results could reflect central facilitation of nociception by NO. However, convergence of nociceptive input from pericranial myofascial tissue and from cephalic blood vessels dilated by NO may provide a more likely explanation. PMID:9245041

  17. Effect of a nitric oxide donor (glyceryl trinitrate) on nociceptive thresholds in man.

    PubMed

    Thomsen, L L; Brennum, J; Iversen, H K; Olesen, J

    1996-05-01

    Several animal studies suggest that nitric oxide (NO) plays a role in central and peripheral modulation of nociception. Glyceryl trinitrate (GTN) exerts its physiological actions via donation of NO. The purpose of the present study was to examine the effect of this NO donor on nociceptive thresholds in man. On two different study days separated by at least a week 12 healthy subjects received a staircase infusion of GTN (0.015, 0.25, 1.0, 2.0 micrograms/kg/min, 20 min each dose) or placebo in a randomized double-blind crossover design. Before the infusion and after 15 min of infusion on each dose, pressure pain detection and tolerance thresholds were determined by pressure algometry (Somomedic AB, Sweden) in three different anatomic regions (finger, a temporal region with interposed myofascial tissue and a temporal region without interposed myofascial tissue). Relative to placebo, the three higher GTN doses induced a decrease in both detection and tolerance thresholds in the temporal region with interposed myofascial tissue (p = 0.003 detection and p = 0.002 tolerance thresholds, Friedman). No such changes were observed in the other two stimulated regions. These results could reflect central facilitation of nociception by NO. However, we regard convergence of nociceptive input from pericranial myofascial tissue and from cephalic blood vessels dilated by NO as a more likely explanation of our findings. PMID:8734768

  18. Formulation of a modified-release pregabalin tablet using hot-melt coating with glyceryl behenate.

    PubMed

    Jeong, Kyu Ho; Woo, Hye Seung; Kim, Chae Jin; Lee, Kyung Hwa; Jeon, Jun Young; Lee, Sang Young; Kang, Jae-Hoon; Lee, Sangkil; Choi, Young Wook

    2015-11-10

    A modified-release (MR) tablet of the anti-anxiety drug pregabalin (PRE) was prepared by hot-melt coating PRE with glyceryl behenate (GB) as a release retardant and compressing to form a matrix with microcrystalline cellulose (MCC) as a hydrophilic diluent. GB-coated PRE had a size in the range of 177-290 μm with good to acceptable flowability. Tablet hardness decreased slightly as GB content increased. PRE release from the tablet matrices was successfully modified by altering the ratio of MCC and GB, and it was found that dissolution- or diffusion-controlled release depended on the amount of GB used. Drug release was pH-independent. An accelerated stability test on the most promising MR tablet at 40°C and 75% relative humidity for 6 months showed no significant changes in PRE content, and the occurrence of total impurities--including PRE-lactam--was within acceptable limits. After oral administration of the selected MR tablet or a commercial IR capsule (Lyrica) to healthy human volunteers, pharmacokinetic parameters including Tmax, Cmax, AUC0-24, and T1/2 were compared. The confidence interval of AUC0-24 was within the adequate range, but that of Cmax was inadequate. This study demonstrated the potential use of GB for PRE-containing MR formulations. PMID:26315121

  19. Development and evaluation of liquid embolic agents based on liquid crystalline material of glyceryl monooleate.

    PubMed

    Du, Ling-Ran; Lu, Xiao-Jing; Guan, Hai-Tao; Yang, Yong-Jie; Gu, Meng-Jie; Zheng, Zhuo-Zhao; Lv, Tian-Shi; Yan, Zi-Guang; Song, Li; Zou, Ying-Hua; Fu, Nai-Qi; Qi, Xian-Rong; Fan, Tian-Yuan

    2014-08-25

    New type of liquid embolic agents based on a liquid crystalline material of glyceryl monooleate (GMO) was developed and evaluated in this study. Ternary phase diagram of GMO, water and ethanol was constructed and three isotropic liquids (ILs, GMO:ethanol:water=49:21:30, 60:20:20 and 72:18:10 (w/w/w)) were selected as potential liquid embolic agents, which could spontaneously form viscous gel cast when contacting with water or physiological fluid. The ILs exhibited excellent microcatheter deliverability due to low viscosity, and were proved to successfully block the saline flow when performed in a device to simulate embolization in vitro. The ILs also showed good cytocompatibility on L929 mouse fibroblast cell line. The embolization of ILs to rabbit kidneys was performed successfully under monitoring of digital subtraction angiography (DSA), and embolic degree was affected by the initial formulation composition and used volume. At 5th week after embolization, DSA and computed tomography (CT) confirmed the renal arteries embolized with IL did not recanalize in follow-up period, and an obvious atrophy of the embolized kidney was observed. Therefore, the GMO-based liquid embolic agents showed feasible and effective to embolize, and potential use in clinical interventional embolization therapy. PMID:24858389

  20. Preparation of multiparticulate vaginal tablet using glyceryl monooleate for sustained progesterone delivery.

    PubMed

    Biradar, Shailesh V; Dhumal, Ravindra S; Shah, Manish H; Paradkar, Anant R; Yamamura, Shigeo

    2009-01-01

    Most of the sustained release vaginal formulations are in the form of bioadhesive gels and tablets. Though proved efficient, their presence in the vagina for a longer time as a bulk produces discomfort and interference with body functioning including sexual activities. Hence, they lack complete patient compliance. In this study, multiparticulate vaginal tablets were prepared by utilizing progesterone (PRO) loaded dry powder precursor of cubic phase (DPPCP) of glyceryl monooleate (GMO). DPPCP were obtained by spray drying GMO with magnesium trisilicate (MTS) and have presented PRO sustained release in simulated vaginal fluid (SVF) for 14 hours. The effect of hydrophilic and hydrophobic tableting excipients on compression, phase, bioadhesion and drug release properties of prepared tablets was evaluated. The effervescent hydrophilic tablet (EHT) prepared with hydrophilic excipients showed rapid disintegration but, diminished sustaining ability owing to transformation into lamellar phase whereas the multiparticulate hydrophobic tablet (MHT) obtained from hydrophobic excipients presented both rapid disintegration and sustained release in SVF by virtue of cubic phase retention. During bioadhesivity testing, fast disintegration of MHT with formation of uniform and viscous bioadhesive layer on cow mucosa was observed even with a small volume of SVF. As MHT may not produce discomfort and interference, it will be preferred over bioadhesive gel or tablet. PMID:18802845

  1. A novel method for the synthesis of glyceryl monocaffeate by the enzymatic transesterification and kinetic analysis.

    PubMed

    Sun, Shangde; Hu, Bingxue

    2017-01-01

    A novel enzymatic method for glyceryl monocaffeate (GMC) preparation by the transesterification of ethyl caffeate (EC) was investigated. The effects of reaction variables (reaction pressure, temperature, reaction time, enzyme load, and substrate ratio) on the enzymatic transesterification were studied and optimized using response surface methodology. HPLC-ESI-MS and HPLC-UV were used to monitor the transesterification. Thermodynamics, kinetic analyses and reaction mechanism were also evaluated. Results showed that, GMC can be successfully prepared by the enzymatic transesterification of EC with glycerol. Under the optimal conditions (enzyme load 22.54%, EC:glycerol=1:12.75 (mol/mol), 72.5°C, and 10.5h), EC conversion and GMC yield were 97.9±0.7% and 95.8±1.0%, respectively. The activation energies (Ea) for EC conversion and GMC formation were 44.23 and 46.51kJ/mol, respectively. The kinetic values for Vmax, Km(') and KIA were 2.18×10(-3)mol/(Lmin), 0.086mol/L, and 0.52mol/L, respectively. The transesterification mechanism with EC inhibition was also proposed. PMID:27507465

  2. RNA Sequencing of Trigeminal Ganglia in Rattus Norvegicus after Glyceryl Trinitrate Infusion with Relevance to Migraine

    PubMed Central

    Hougaard Pedersen, Sara; Maretty, Lasse; Ramachandran, Roshni; Sibbesen, Jonas Andreas; Yakimov, Victor; Elgaard-Christensen, Rikke; Hansen, Thomas Folkmann; Krogh, Anders; Olesen, Jes; Jansen-Olesen, Inger

    2016-01-01

    Introduction Infusion of glyceryl trinitrate (GTN), a donor of nitric oxide, induces immediate headache in humans that in migraineurs is followed by a delayed migraine attack. In order to achieve increased knowledge of mechanisms activated during GTN-infusion this present study aims to investigate transcriptional responses to GTN-infusion in the rat trigeminal ganglia. Methods Rats were infused with GTN or vehicle and trigeminal ganglia were isolated either 30 or 90 minutes post infusion. RNA sequencing was used to investigate transcriptomic changes in response to the treatment. Furthermore, we developed a novel method for Gene Set Analysis Of Variance (GSANOVA) to identify gene sets associated with transcriptional changes across time. Results 15 genes displayed significant changes in transcription levels in response to GTN-infusion. Ten of these genes showed either sustained up- or down-regulation in the 90-minute period after infusion. The GSANOVA analysis demonstrate enrichment of pathways pointing towards an increase in immune response, signal transduction, and neuroplasticity in response to GTN-infusion. Future functional in-depth studies of these mechanisms are expected to increase our understanding of migraine pathogenesis. PMID:27213950

  3. Glyceryl monooleate-based otic delivery system of ofloxacin: release profile and bactericidal activity.

    PubMed

    Adwan, Samer; Abu-Dahab, Rana; Al-Bakri, Amal G; Sallam, Alsayyed

    2015-05-01

    This study investigated the preparation and characterization of glyceryl monooleate- (GMO) based drug delivery system containing ofloxacin for the treatment of otitis externa. Acetate buffer (pH 4.5) containing dissolved ofloxacin was added to molten GMO as an aqueous phase, this resulted in the formation of a cubic and a reverse hexagonal phases. The release behavior of ofloxacin from the drug delivery system was studied using three different methods. The mechanism of drug release using paddles/dissolution apparatus and Franz diffusion cells followed Higuchi and Fickian diffusion models; whereas intrinsic release rate method showed zero-order kinetics. The intrinsic release rate was estimated and found to be 187.2 µg/cm(2)/h. The release mechanisms were similar irrespective of the loaded ofloxacin amount, however, the higher drug load displayed higher release rate. The drug delivery system was proven to be microbiologically effective by using agar diffusion method, against Staphylococcus aureus, and Pseudomonas aeruginosa. The GMO/ofloxacin formulation was stable for 6 months after preparation at room temperature as measured with respect to phase stability and antibacterial activity. PMID:24392877

  4. Acute and chronic effects of glyceryl trinitrate therapy on insulin and glucose regulation in humans.

    PubMed

    Jedrzkiewicz, Sean; Parker, John D

    2013-05-01

    This study examined the effect of acute and sustained transdermal glyceryl trinitrate (GTN) therapy on insulin and glucose regulation. Totally, 12 males (18-30 years) underwent a glucose tolerance test at baseline (visit 1), 90 minutes after acute transdermal GTN 0.6 mg/h (visit 2), following 7 days of continuous GTN (visit 3), and 2 to 3 days after stopping GTN (visit 4). At each visit, plasma glucose and insulin concentrations were measured before and 30, 60, 90, and 120 minutes after a 75-g oral glucose load. Indices of glucose metabolism that were examined included the insulin sensitivity index, the homeostasis model assessment of insulin resistance (HOMA-IR), and the insulinogenic index. The acute administration of GTN had no effect on glucose and insulin responses (visit 2). However, after 7 days of GTN exposure (visit 3) there was an increase in the mean glucose concentration measured after the oral glucose load. On visit 1, the mean glucose concentration (± standard deviation) following the 75 g oral glucose challenge was 5.7 ± 0.5 µmol/L. On visit 3, after 7 days of transdermal GTN therapy, the mean glucose concentration after the oral glucose was significantly higher; 6.2 ± 0.5 µmol/L (P < .015; 95% confidence intervals 0.25-0.77). There was also an increase in the HOMA-IR index; on visit 1, the median HOMA-IR (interquartile range) was 5.2 (3.9) versus 6.9 (6.8) on visit 3 (P < .015). Other indices of glucose metabolism did not change. These observations document that GTN therapy modifies glucose metabolism causing evidence of increased insulin resistance during sustained therapy in normal humans. PMID:23230283

  5. Investigation of oxidant stress and vasodepression to glyceryl trinitrate in the obese Zucker rat in vivo

    PubMed Central

    Laight, David W; Kengatharan, K M; Gopaul, Nitin K; Änggård, Erik E; Carrier, Martin J

    1998-01-01

    We examined the relationship between oxidant stress and the vasodepressor activity of glyceryl trinitrate (GTN) in vivo, including rapid GTN tolerance development, in 13-week old obese and age-matched lean Zucker rats which had been maintained for 4 weeks on either control diet or diets enriched with the lipophilic, chain-breaking antioxidants vitamin E (0.5% w w−1) or probucol (0.5% w w−1) or the superoxide anion scavenger tiron (1% w v−1 in drinking water).The basal plasma level of the isoprostane 8-epi-PGF2α, an in vivo marker of lipid peroxidation, was elevated by approximately 5 fold in the obese Zucker rat and markedly reduced by dietary lipophilic antioxidants and depressed by dietary tiron.Vasodepression to bolus does GTN (0.1–100 μg kg−1 i.v.), but not endothelium-dependent vasodepression to bolus dose acetylcholine (ACh, 0.02–2.0 μg kg−1 i.v.), was impaired in obese animals and completely restored by dietary antioxidants.Nitrate tolerance developed in vivo during a 1 h infusion of GTN (40 μg kg−1 min−1 i.v.) appeared more severe in obese animals. However, rapid nitrate tolerance was not affected by dietary antioxidants in either the obese or lean Zucker rat.We therefore provide evidence that elevated oxidant stress in the obese Zucker rat is associated with an impairment in nitrate vasodepressor activity. However, our data are not consistent with either a role for oxidant stress in rapid nitrate tolerance development in the anaesthetized Zucker rat or the aggravation of this tolerance by pre-existing oxidant stress. PMID:9831930

  6. Novel glyceryl glucoside is a low toxic alternative for cryopreservation agent.

    PubMed

    Su, Cathy; Allum, Allison J; Aizawa, Yasushi; Kato, Takamitsu A

    2016-08-01

    Glyceryl glucoside (GG, α-d-glucosyglycerol) is a natural glycerol derivative found in alcoholic drinks. Recently GG has been used as an alternative for glycerol in cosmetic products. However, the safety of using GG is still unclear. Currently, dimethyl sulfoxide (DMSO) and glycerol are wildly used in cryopreservation. Despite GG being a derivative of glycerol, the ability of GG in cryopreservation is still unknown. By using a system of Chinese Hamster Ovary cells (CHO), A549 cells and AG1522 cells, the study examined the cryoprotective effects of DMSO, glycerol and GG. Cytotoxic and genotoxic responses induced by the three chemicals were also investigated with CHO to determine the safety of GG for cosmetic products. Our data suggests that GG has great cryopresearvation ability in the concentration of 30%-40% (v/v). For cytotoxic studies, DMSO showed the highest cytotoxicity above 3% (v/v) in cell doubling time delay among three chemicals. For the acute cytotoxicity with trypan blue dye exclusion assay, GG showed stronger cell killing effect within 24 h above 4% (v/v). For the continuous cytotoxicity with colony formation assay for 7 days, DMSO showed significantly reduced clonogenic ability above 2%. In genotoxicity studies, CHO treated with glycerol at 2% concentration induced three times higher frequencies of sister chromatid exchange (SCE) than background levels. GG did not induce significant amounts of SCE compared to background. Micronuclei formation was equally observed in the 2% and above concentrations of glycerol and GG. Our data showed that GG has significant effects on cryopreservation compared to DMSO. Glycerol and GG have similar cytotoxicity effects to CHO, but glycerol induced genotoxic responses in the same concentration. Therefore, we conclude that GG may be a safer alternative compound to glycerol in cosmetic products and safer alternative to DMSO in cryopreservation. PMID:27235553

  7. Chitosan and glyceryl monooleate nanostructures containing gemcitabine: potential delivery system for pancreatic cancer treatment.

    PubMed

    Trickler, William J; Khurana, Jatin; Nagvekar, Ankita A; Dash, Alekha K

    2010-03-01

    The objectives of this study are to enhance cellular accumulation of gemcitabine with chitosan/glyceryl monooleate (GMO) nanostructures, and to provide significant increase in cell death of human pancreatic cancer cells in vitro. The delivery system was prepared by a multiple emulsion solvent evaporation method. The nanostructure topography, size, and surface charge were determined by atomic force microscopy (AFM), and a zetameter. The cellular accumulation, cellular internalization and cytotoxicity of the nanostructures were evaluated by HPLC, confocal microscopy, or MTT assay in Mia PaCa-2 and BxPC-3 cells. The average particle diameter for 2% and 4% (w/w) drug loaded delivery system were 382.3 +/- 28.6 nm, and 385.2 +/- 16.1 nm, respectively with a surface charge of +21.94 +/- 4.37 and +21.23 +/- 1.46 mV. The MTT cytotoxicity dose-response studies revealed the placebo at/or below 1 mg/ml has no effect on MIA PaCa-2 or BxPC-3 cells. The delivery system demonstrated a significant decrease in the IC50 (3 to 4 log unit shift) in cell survival for gemcitabine nanostructures at 72 and 96 h post-treatment when compared with a solution of gemcitabine alone. The nanostructure reported here can be resuspended in an aqueous medium that demonstrate increased effective treatment compared with gemcitabine treatment alone in an in vitro model of human pancreatic cancer. The drug delivery system demonstrates capability to entrap both hydrophilic and hydrophobic compounds to potentially provide an effective treatment option in human pancreatic cancer. PMID:20238190

  8. Analysis of responses to glyceryl trinitrate and sodium nitrite in the intact chest rat.

    PubMed

    Nossaman, Bobby D; Pankey, Edward A; Badejo, Adeleke R; Casey, David B; Uppu, Satvika; Murthy, Subramanyam N; Kadowitz, Philip J

    2012-05-15

    Responses to glyceryl trinitrate/nitroglycerin (GTN), S-nitrosoglutathione (GSNO), and sodium nitrite were compared in the intact chest rat. The iv injections of GTN, sodium nitrite, and GSNO produced dose-dependent decreases in pulmonary and systemic arterial pressures. In as much as cardiac output was not reduced, the decreases in pulmonary and systemic arterial pressures indicate that GTN, sodium nitrite, and GSNO have significant vasodilator activity in the pulmonary and systemic vascular beds in the rat. Responses to GTN were attenuated by cyanamide, but not allopurinol, whereas responses to nitrite formed by the metabolism of GTN were attenuated by allopurinol and cyanamide. The results with allopurinol and cyanamide suggest that only mitochondrial aldehyde dehydrogenase is involved in the bioactivation of GTN, sodium nitrite, and GSNO, whereas both pathways are involved in the bioactivation of nitrite anion in the intact rat. The comparison of vasodilator activity indicates that GSNO and GTN are more than 1000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures in the rat. Following administration of 1H-[1,2,4]-oxadizaolo[4,3-]quinoxaline-1-one (ODQ), responses to GTN were significantly attenuated, indicating that responses are mediated by the activation of soluble guanylyl cyclase. These data suggest that the reduction of nitrite to nitric oxide formed from the metabolism of GTN, cannot account for the vasodilator activity of GTN in the intact rat and that another mechanism; perhaps the formation of an S-NO, may mediate the vasodilator response to GTN in this species. PMID:22465477

  9. Analysis of Responses to Glyceryl Trinitrate and Sodium Nitrite in the Intact Chest Rat

    PubMed Central

    Nossaman, Bobby D.; Pankey, Edward A.; Badejo, Adeleke R.; Casey, David B.; Uppu, Satvika; Murthy, Subramanyam N.; Kadowitz, Philip J.

    2012-01-01

    Responses to glyceryl trinitrate/nitroglycerin (GTN), S-nitrosoglutathione (GSNO), and sodium nitrite were compared in the intact chest rat. The iv injections of GTN, sodium nitrite, and GSNO produced dose-dependent decreases in pulmonary and systemic arterial pressures. In as much as cardiac output was not reduced, the decreases in pulmonary and systemic arterial pressures indicate that GTN, sodium nitrite, and GSNO have significant vasodilator activity in the pulmonary and systemic vascular beds in the rat. Responses to GTN were attenuated by cyanamide, but not allopurinol, whereas responses to nitrite formed by the metabolism of GTN were attenuated by allopurinol and cyanamide. The results with allopurinol and cyanamide suggest that only mitochondrial aldehyde dehydrogenase is involved in the bioactivation of GTN, sodium nitrite, and GSNO, whereas both pathways are involved in the bioactivation of nitrite anion in the intact rat. The comparison of vasodilator activity indicates that GSNO and GTN are more than 1000 fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures in the rat. Following administration of 1H-[1,2,4]-oxadizaolo[4,3-]quinoxaline-1-one (ODQ), responses to GTN were significantly attenuated, indicating that responses are mediated by the activation of soluble guanylyl cyclase. These data suggest that the reduction of nitrite to nitric oxide formed from the metabolism of GTN, cannot account for the vasodilator activity of GTN in the intact rat and that another mechanism; perhaps the formation of an S-NO, may mediate the vasodilator response to GTN in this species. PMID:22465477

  10. Mitochondrial aldehyde dehydrogenase mediates vasodilator responses of glyceryl trinitrate and sodium nitrite in the pulmonary vascular bed of the rat.

    PubMed

    Badejo, Adeleke M; Hodnette, Chris; Dhaliwal, Jasdeep S; Casey, David B; Pankey, Edward; Murthy, Subramanyam N; Nossaman, Bobby D; Hyman, Albert L; Kadowitz, Philip J

    2010-09-01

    It has been reported that mitochondrial aldehyde dehydrogenase (ALDH2) catalyzes the formation of glyceryl dinitrate and inorganic nitrite from glyceryl trinitrate (GTN), leading to an increase in cGMP and vasodilation in the coronary and systemic vascular beds. However, the role of nitric oxide (NO) formed from nitrite in mediating the response to GTN in the pulmonary vascular bed is uncertain. The purpose of the present study was to determine if nitrite plays a role in mediating vasodilator responses to GTN. In this study, intravenous injections of GTN and sodium nitrite decreased pulmonary and systemic arterial pressures and increased cardiac output. The decreases in pulmonary arterial pressure under baseline and elevated tone conditions and decreases in systemic arterial pressure in response to GTN and sodium nitrite were attenuated by cyanamide, an ALDH2 inhibitor, whereas responses to the NO donor, sodium nitroprusside (SNP), were not altered. The decreases in pulmonary and systemic arterial pressure in response to GTN and SNP were not altered by allopurinol, an inhibitor of xanthine oxidoreductase, whereas responses to sodium nitrite were attenuated. GTN was approximately 1,000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures. These results suggest that ALDH2 plays an important role in the bioactivation of GTN and nitrite in the pulmonary and systemic vascular beds and that the reduction of nitrite to vasoactive NO does not play an important role in mediating vasodilator responses to GTN in the intact chest rat. PMID:20543077

  11. Mitochondrial aldehyde dehydrogenase mediates vasodilator responses of glyceryl trinitrate and sodium nitrite in the pulmonary vascular bed of the rat

    PubMed Central

    Badejo, Adeleke M.; Hodnette, Chris; Dhaliwal, Jasdeep S.; Casey, David B.; Pankey, Edward; Murthy, Subramanyam N.; Nossaman, Bobby D.; Hyman, Albert L.

    2010-01-01

    It has been reported that mitochondrial aldehyde dehydrogenase (ALDH2) catalyzes the formation of glyceryl dinitrate and inorganic nitrite from glyceryl trinitrate (GTN), leading to an increase in cGMP and vasodilation in the coronary and systemic vascular beds. However, the role of nitric oxide (NO) formed from nitrite in mediating the response to GTN in the pulmonary vascular bed is uncertain. The purpose of the present study was to determine if nitrite plays a role in mediating vasodilator responses to GTN. In this study, intravenous injections of GTN and sodium nitrite decreased pulmonary and systemic arterial pressures and increased cardiac output. The decreases in pulmonary arterial pressure under baseline and elevated tone conditions and decreases in systemic arterial pressure in response to GTN and sodium nitrite were attenuated by cyanamide, an ALDH2 inhibitor, whereas responses to the NO donor, sodium nitroprusside (SNP), were not altered. The decreases in pulmonary and systemic arterial pressure in response to GTN and SNP were not altered by allopurinol, an inhibitor of xanthine oxidoreductase, whereas responses to sodium nitrite were attenuated. GTN was ∼1,000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures. These results suggest that ALDH2 plays an important role in the bioactivation of GTN and nitrite in the pulmonary and systemic vascular beds and that the reduction of nitrite to vasoactive NO does not play an important role in mediating vasodilator responses to GTN in the intact chest rat. PMID:20543077

  12. Roles of potassium ions, acetyl and L-glyceryl groups in native gellan double helix: an X-ray study.

    PubMed

    Chandrasekaran, R; Radha, A; Thailambal, V G

    1992-02-01

    Native gellan, the natural form of the polysaccharide excreted by the bacterium Pseudomonas elodea, has a tetrasaccharide repeating unit that contains L-glycerol and acetate ester groups, and forms only weak and elastic gels. Based on X-ray diffraction data from well oriented and polycrystalline fibers of its potassium salt, the crystal structure of native gellan, including ions and water, has been determined and refined to a final R-value of 0.17. The molecule forms of a half-staggered, parallel, double helix of pitch 5.68 nm which is stabilized by hydrogen bonds involving the hydroxymethyl groups in one chain and both carboxylate and glyceryl groups in other. Two molecules are packed in an antiparallel fashion in a trigonal unit cell of side a = 1.65 nm. Although the gross molecular morphology and packing arrangements are isomorphous with those observed in the crystal structure of potassium gellan, which is devoid of any substitutions, native gellan exhibits exceptional changes in its ion binding characteristics with respect to gellan. In particular, the L-glyceryl groups do not allow the gellan-like coordinated interactions of the ions and the carbohydrate groups, within and between double helices, which are necessary for strong gelation. These results at the molecular level explain, for the first time, the differences in the behavior of the polymer with and without substitutions. PMID:1591755

  13. Computational and Biological Evaluation of N-octadecyl-N′-propylsulfamide, a Selective PPARα Agonist Structurally Related to N-acylethanolamines

    PubMed Central

    Serrano, Antonia; Cano, Carolina; Suardíaz, Margarita; Decara, Juan; Suarez, Juan; de Fonseca, Fernando Rodríguez; Macías-González, Manuel

    2014-01-01

    To further understand the pharmacological properties of N-oleoylethanolamine (OEA), a naturally occurring lipid that activates peroxisome proliferator-activated receptor alpha (PPARα), we designed sulfamoyl analogs based on its structure. Among the compounds tested, N-octadecyl-N′-propylsulfamide (CC7) was selected for functional comparison with OEA. The performed studies include the following computational and biological approaches: 1) molecular docking analyses; 2) molecular biology studies with PPARα; 3) pharmacological studies on feeding behavior and visceral analgesia. For the docking studies, we compared OEA and CC7 data with crystallization data obtained with the reference PPARα agonist GW409544. OEA and CC7 interacted with the ligand-binding domain of PPARα in a similar manner to GW409544. Both compounds produced similar transcriptional activation by in vitro assays, including the GST pull-down assay and reporter gene analysis. In addition, CC7 and OEA induced the mRNA expression of CPT1a in HpeG2 cells through PPARα and the induction was avoided with PPARα-specific siRNA. In vivo studies in rats showed that OEA and CC7 had anorectic and antiobesity activity and induced both lipopenia and decreases in hepatic fat content. However, different effects were observed when measuring visceral pain; OEA produced visceral analgesia whereas CC7 showed no effects. These results suggest that OEA activity on the PPARα receptor (e.g., lipid metabolism and feeding behavior) may be dissociated from other actions at alternative targets (e.g., pain) because other non cannabimimetic ligands that interact with PPARα, such as CC7, do not reproduce the full spectrum of the pharmacological activity of OEA. These results provide new opportunities for the development of specific PPARα-activating drugs focused on sulfamide derivatives with a long alkyl chain for the treatment of metabolic dysfunction. PMID:24651609

  14. Formulation of an oral dosage form utilizing the properties of cubic liquid crystalline phases of glyceryl monooleate.

    PubMed

    Sallam, Al-Sayed; Khalil, Enam; Ibrahim, Hussain; Freij, Ibtisam

    2002-05-01

    Glyceryl monooleate is a Food and Drug Administration-approved food additive which has the ability to form various liquid crystalline phases in the presence of various amounts of water. The unique properties of the cubic liquid crystalline phase that result upon the presence of excess body fluids at body temperature were utilized to formulate an oral dosage form containing furosemide as the model drug. The aim was to develop a formula, which has both bioadhesive and sustained release properties of the resultant cubic phase, so that increasing gastric residence time to improve bioavailability of the drug and at the same time obtaining a sustained action. The system was found to be affected by the limited solubility of furosemide in both the carrier system and the pH of surrounding medium. As a consequence, the addition of some solubility modifiers was investigated in order to obtain the desired properties of the expected liquid crystalline system. PMID:11976023

  15. H89 enhances the sensitivity of cancer cells to glyceryl trinitrate through a purinergic receptor-dependent pathway

    PubMed Central

    Cortier, Marion; Boina-Ali, Rahamata; Racoeur, Cindy; Paul, Catherine; Solary, Eric; Jeannin, Jean-François; Bettaieb, Ali

    2015-01-01

    High doses of the organic nitrate glyceryl trinitrate (GTN), a nitric oxide (NO) donor, are known to trigger apoptosis in human cancer cells. Here, we show that such a cytotoxic effect can be obtained with subtoxic concentrations of GTN when combined with H89, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulphonamide.2HCl. This synergistic effect requires the generation of reactive oxygen species (ROS) from H89 and NO from GTN treatment that causes cGMP production and PKG activation. Furthermore, the GTN/H89 synergy was attenuated by inhibition of P2-purinergic receptors with suramin and competition with ATP/UDP. By down-regulating genes with antisense oligonucleotides, P2-purinergic receptors P2X3, P2Y1, and P2Y6 were found to have a role in creating this cytotoxic effect. Thus, H89 likely acts as an ATP mimetic synergizing with GTN to trigger apoptosis in aggressive cancer cells. PMID:25762630

  16. H89 enhances the sensitivity of cancer cells to glyceryl trinitrate through a purinergic receptor-dependent pathway.

    PubMed

    Cortier, Marion; Boina-Ali, Rahamata; Racoeur, Cindy; Paul, Catherine; Solary, Eric; Jeannin, Jean-François; Bettaieb, Ali

    2015-03-30

    High doses of the organic nitrate glyceryl trinitrate (GTN), a nitric oxide (NO) donor, are known to trigger apoptosis in human cancer cells. Here, we show that such a cytotoxic effect can be obtained with subtoxic concentrations of GTN when combined with H89, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulphonamide.2HCl. This synergistic effect requires the generation of reactive oxygen species (ROS) from H89 and NO from GTN treatment that causes cGMP production and PKG activation. Furthermore, the GTN/H89 synergy was attenuated by inhibition of P2-purinergic receptors with suramin and competition with ATP/UDP. By down-regulating genes with antisense oligonucleotides, P2-purinergic receptors P2X3, P2Y1, and P2Y6 were found to have a role in creating this cytotoxic effect. Thus, H89 likely acts as an ATP mimetic synergizing with GTN to trigger apoptosis in aggressive cancer cells. PMID:25762630

  17. Octadecyl functionalized core-shell magnetic silica nanoparticle as a powerful nanocomposite sorbent to extract urinary volatile organic metabolites.

    PubMed

    Qiao, Zheng; Perestrelo, Rosa; Reyes-Gallardo, Emilia M; Lucena, R; Cárdenas, S; Rodrigues, João; Câmara, José S

    2015-05-01

    In this present study, magnetic Fe3O4@SiO2 nanoparticles (MNPs) functionalized with octadecyl groups (Fe3O4@SiO2-C18 NPs) were synthesized, characterized and employed, for the first time, as powerful nanosorbent to extract endogenous volatile organic metabolites (EVOMs) namely, hexanal, heptanal, decanal, benzaldehyde, 4-heptanone, 5-methyl-2-furfural and phenol, described as potential biomarkers of cancer, from human urine. By using co-precipitation, surface modification methods, the carbon-ferromagnetic nanocomposite was synthesized and characterized by infrared spectrum (IR) and transmission electron microscopy (TEM). By coupling with gas chromatography-mass spectrometry (GC-qMS), a reliable, sensitive and cost-effective method was validated. To test the extraction efficiency of the carbon-ferromagnetic nanocomposite toward urinary EVOMs experimental variables affecting the extraction performance, including nanosorbent amount, adsorption time, elution time, and nature of elution solvent, were investigated in detail. The extraction process was performed by dispersing Fe3O4@SiO2-C18 NPs into working solution containing targeted VOMs, and into urine samples, and then eluted with an adequate organic solvent. The eluate was collected, concentrated and analyzed by GC-qMS. Under the optimized conditions, the LODs and LOQs achieved were in the range of 9.7-57.3 and 32.4-190.9ng/mL, respectively. Calibration curves were linear (r(2)≥0. 988) over the concentration ranges from 0.25 to 250ng/mL. In addition, a satisfying reproducibility was achieved by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) less than 3 and 11%, respectively. The method also afforded satisfactory results in terms of the matrix effect (72.8-96.1%) and recoveries (accuracy) higher than 75.1% for most of the studied EVOMs. The Fe3O4@SiO2-C18 NPs-based sorbent extraction combined with GC-qMS revealed that the new nanosorbent had a strong ability to retain the

  18. Octadecyl bonded silica membrane disk modified with Cyanex302 for separation and flame atomic absorption spectrometric determination of nickel from tap water and industrial effluent.

    PubMed

    Karve, Manjusha; Rajgor, Reeta V

    2009-07-15

    A simple and reliable method based upon impregnation of Cyanex302 on octadecyl bonded silica membrane disk has been developed for separation and atomic absorption spectrometric determination of nickel. The influence of various parameters like aqueous phase pH, flow rate and volume of eluent were investigated systematically to optimize the conditions for quantitative sorption and desorption of nickel. The break through volume for nickel was greater than 1.0 dm(3), enrichment factor more than 100 and a detection limit of 2.1 microg dm(-3) was achieved. The method applied for detection of nickel in tap water and effluent sample had a relative standard deviation (R.S.D.) of 0.4%. PMID:19124200

  19. Surfactant-mediated capillary electrochromatography with octadecyl-silica- packed capillary columns for the separation of nonpolar compounds. Case of pyrethroid insecticides.

    PubMed

    Tegeler, Tony; El-Rassi, Ziad

    2002-05-01

    Capillary electrochromatography (CEC) with octadecyl-silica-packed capillary columns was evaluated in the separation of nonpolar compounds, e.g., pyrethroid insecticides, using surfactant-rich mobile phases. This novel concept is referred to as surfactant-mediated capillary electrochromatography (SM-CEC), and is based on including a charged surfactant, namely sodium di-2-ethylhexyl sulfosuccinate (DOSS), in the mobile phase. Under these conditions, DOSS plays the role of a slowly moving pseudostationary phase so that solutes are partitioned between a mobile phase, a fixed stationary phase and a slowly moving pseudostationary phase. The SM-CEC system was investigated with pyrethroid insecticides over a wide range of DOSS and acetonitrile concentrations in the mobile phase. Pyrethroid insecticides, which are very hydrophobic solutes consisting of geometric isomers and diastereomers, were better resolved in SM-CEC than in straight CEC. PMID:12007119

  20. The second harmonic generation and the photoelectric property studies on a new dye, (E)- N-octadecyl-4-[2-(4-dimethylaminophenyl) enamine] pyridinium iodide

    NASA Astrophysics Data System (ADS)

    Zhai, Jin; Huang, Chun-Hui; Wei, Tian-Xin; Yu, An-Chi; Zhao, Xin-Sheng

    1999-03-01

    According to quantum chemistry calculation, a Schiff-base (E)- N-octadecyl-4-[2-(4-dimethylaminophenyl) enamine] pyridinium iodide with a large dipole moment difference between the excited state and the ground state (Δ μ), is designed and synthesized as a second-order non-linear optical material. Its second-order susceptibility ( χ(2)zzz) is evaluated to be 279.4 pm V -1, which is larger than that of the hemicyanine which is known as one of the best dyes in the second harmonic generation (SHG) behavior. Its LB film formation properties were studied. The photoelectric conversion property is not as good as expected. According to the experiments and the results of the quantum chemistry calculation, an explanation of this phenomenon is proposed.

  1. Fluorescent turn-on detection and assay of water based on 4-(2-dimethylaminoethyloxy)-N-octadecyl-1,8-naphthalimide with aggregation-induced emission enhancement.

    PubMed

    Sun, Yang; Liang, Xuhua; Wei, Song; Fan, Jun; Yang, Xiaohui

    2012-11-01

    The photophysical properties of 4-(2-dimethylaminoethyloxy)-N-octadecyl-1,8-naphthalimide (DON) consisting of donor and acceptor units were investigated in different solutions. Changing from a non-polar to a polar solvent increased the solvent interaction and both the excitation and emission spectra were shifted to longer wavelength and intensity decreased through taking advantage of twisted intramolecular charge transfer (TICT). Density functional theory (DFT) calculations and spectral analyses revealed that such fluorophores were capable of sensing protons by intramolecular charge transfer (ICT). Empirical and quantum mechanical calculations showed that the electron donating effect of the dimethylamino group decreased the change in dipole moment on excitation which resulted in a fluorescence quantum yield remarkably enhanced as the solvent polarity increased. In alkaline media the fluorescence of DON was quenched owing to photoinduced electron transfer being disabled in acidic media. The pK(a) of the 1,8-naphthailimide dye was 6.70, which defines the dye as a highly efficient "off-on" switch. DON exhibited a typical aggregation-induced emission enhancement (AIEE) behavior that it is virtually nonemissive in organic solvent but highly luminescent in water, as a result of the restriction of free intramolecular rotation of a C-N bond and the non-planar configuration in the aggregate state. The hydrophobicity of octadecyl group provided DON with a fluorescent response to water based on AIEE and the water-dependent spectral characteristics of DON, and the AIEE of DON caused by the effect of water and formation of J-aggregation states. In the range of 0-79.8% (v/v), the fluorescence intensity of DON in acetone solution increased as a linear function of the water content. The optimum detection limits were of 0.011%, 0.0021%, and 0.0033% of water in acetone, ethanol, and acetonitrile, respectively. Satisfactory reproducibility, reversibility and a short response time

  2. Assessment of skin absorption and irritation potential of arachidonic acid and glyceryl arachidonate using in vitro diffusion cell techniques.

    PubMed

    Eppler, A R; Kraeling, M E K; Wickett, R R; Bronaugh, R L

    2007-11-01

    Arachidonic acid (AA), a precursor of pro-inflammatory mediators, and its glycerin ester, glyceryl arachidonate (GA), are reportedly used in cosmetic products. In vitro skin penetration of AA and GA and GA's ester hydrolysis was determined in flow-through diffusion cells. AA penetration with human and rat skin was 19.5% and 52.3% of the applied dose respectively, a substantial amount of which remained in the skin at 24h. Similar penetration results were obtained with GA in human skin. However, GA penetration through cultured skin (EpiDerm) was 51% of the applied dose, almost all of which appeared in the receptor fluid. At least 27.8% of GA penetrating skin was hydrolyzed to AA. In vitro methods were used to assess skin irritation in diffusion cells. Skin irritation of AA, sodium lauryl sulfate (SLS), and Tween 80 was determined by changes in transepidermal water loss (TEWL), skin viability (3-(4,5-dimethylthiaxol-2-yl)-2,5-diphenyltetrazolium bromide, MTT, formation), and cytokine release (IL-1alpha). SLS irritation was much less pronounced in an emulsion versus an aqueous vehicle. No significant irritation was observed in vitro from AA in an emulsion. This work predicts that AA would penetrate human skin in vivo and that it could be formed in skin from topically applied GA. PMID:17602815

  3. Liquid crystalline systems of phytantriol and glyceryl monooleate containing a hydrophilic protein: Characterisation, swelling and release kinetics.

    PubMed

    Rizwan, S B; Hanley, T; Boyd, B J; Rades, T; Hook, S

    2009-11-01

    Swelling and phase behaviour of phytantriol and glyceryl monooleate (GMO) matrices with varying water loadings were investigated. Release of a model protein, FITC-Ova was subsequently examined. Polarised light microscopy and small angle X-ray scattering analysis showed that the addition of FITC-Ova only altered the liquid crystalline structure of phytantriol matrices at low water loadings, and that postrelease study, the phase structure of matrices at both low and high loading reflected that of the binary system. Addition of FITC-Ova to GMO matrices also altered the liquid crystalline structure when compared to the respective binary system at low but not at high loading. All samples analysed after the release study had transformed to the reverse hexagonal phase (H(II)). Swelling studies revealed a faster and more extensive swelling of GMO when compared to phytantriol. Release of FITC-Ova from phytantriol matrices was faster and occurred to a greater extent most likely due to the conversion of GMO matrices into the H(II) phase. No effect on release as a function of initial water content was observed for either lipid. We have confirmed that phytantriol based liquid crystalline matrices can sustain the release of a hydrophilic protein, suggesting its suitability as a potential sustained antigen-delivery system. PMID:19340889

  4. Glyceryl trinitrate and caprylic acid for the mitigation of the Desulfovibrio vulgaris biofilm on C1018 carbon steel.

    PubMed

    Li, Y; Zhang, P; Cai, W; Rosenblatt, J S; Raad, I I; Xu, D; Gu, T

    2016-02-01

    Microbiologically influenced corrosion (MIC), also known as biocorrosion, is caused by corrosive biofilms. MIC is a growing problem, especially in the oil and gas industry. Among various corrosive microbes, sulfate reducing bacteria (SRB) are often the leading culprit. Biofilm mitigation is the key to MIC mitigation. Biocide applications against biofilms promote resistance over time. Thus, it is imperative to develop new biodegradable and cost-effective biocides for large-scale field applications. Using the corrosive Desulfovibrio vulgaris (an SRB) biofilm as a model biofilm, this work demonstrated that a cocktail of glyceryl trinitrate (GTN) and caprylic acid (CA) was very effective for biofilm prevention and mitigation of established biofilms on C1018 carbon steel coupons. The most probable number sessile cell count data and confocal laser scanning microscope biofilm images proved that the biocide cocktail of 25 ppm (w/w) GTN + 0.1% (w/w) CA successfully prevented the D. vulgaris biofilm establishment on C1018 carbon steel coupons while 100 ppm GTN + 0.1% CA effectively mitigated pre-established D. vulgaris biofilms on C1018 carbon steel coupons. In both cases, the cocktails were able to reduce the sessile cell count from 10(6) cells/cm(2) to an undetectable level. PMID:26745983

  5. The effect of the nitric oxide donor glyceryl trinitrate on global and regional cerebral blood flow in man.

    PubMed

    White, R P; Deane, C; Hindley, C; Bloomfield, P M; Cunningham, V J; Vallance, P; Brooks, D J; Markus, H S

    2000-09-01

    Despite their potential use as cerebral vasodilatory agents there are few studies of the effect of nitric oxide (NO) donors on the cerebral circulation in non-anaesthetised man. We determined the effect of the NO donor glyceryl trinitrate (GTN) at clinically relevant doses on global and regional cerebral blood flow (CBF) in healthy non-anaesthetised volunteers, using H(2)(15)O PET, ultrasonic colour velocity flow imaging of carotid artery flow, and transcranial Doppler (TCD) of middle cerebral artery velocities (MCAv). Three rates of GTN infusion (0.1, 0.4, 1.0 microg/kg/min) were used. There was no significant change in common or internal carotid artery flow following GTN administration although a dose dependent fall in MCAv post GTN was observed. There was no significant change in either global or regional CBF following GTN. Thus intravenous GTN at therapeutic doses in awake humans does not alter global or regional CBF. However it does produce basal cerebral artery vasodilatation as evidenced by a fall in MCAv in the absence of a change in internal carotid artery flow. PMID:11018245

  6. The Effects of Glyceryl Trinitrate Patch on the Treatment of Preterm Labor: A Single-blind Randomized Clinical Trial

    PubMed Central

    Nankali, Anisodowleh; Jamshidi, Parnian Kord; Rezaei, Mansour

    2014-01-01

    Background Preterm labor (PTL) is one of the main causes of neonatal mortality and morbidity. PTL leads to serious complications especially in the gestational age prior to 24-26 weeks. The aim of this study was to investigate the effect of glyceryl trinitrate (GTN) patch on the treatment and complications of PTL. Methods In this clinical trial, 84 singleton pregnant women with gestational age of 27-35 weeks were surveyed. PTL was clinically diagnosed and the patients were randomly divided into two groups who were treated with GTN or placebo for 48 hr. The consequences, complications and changes in some parameters in both groups were compared. Data were analyzed with chi square test, paired and unpaired t tests by SPSS software and p<0.05 was considered significant. Results No significant difference was observed between two groups in terms of successful tocolysis, receiving full dose of corticosteroids and the mean prolongation of the pregnancy. However, delivery times in patients who delivered during the hospitalization were 31±4.4 and 18.3±2.2 hr (p=0.01), respectively. Headache was more severe in control group (p=0.007). The systolic and mean arterial blood pressure decrease (p<0.001) and maternal heart rate increase (p=0.01) were significant in GTN group. The changes of vital signs were not significant in placebo group. Conclusion The effect of GTN in the treatment of PTL is similar to the placebo without any serious complication. However, GTN delays the delivery time in delivery during the primary hospitalization. Thus, further studies with larger sample size are needed to evaluate the exact effects of GTN on PTL. PMID:24918079

  7. Glyceryl monooleyl ether-based liquid crystalline nanoparticles as a transdermal delivery system of flurbiprofen: characterization and in vitro transport.

    PubMed

    Uchino, Tomonobu; Murata, Akiko; Miyazaki, Yasunori; Oka, Toshihiko; Kagawa, Yoshiyuki

    2015-01-01

    Liquid crystalline nanoparticles (LCNs) were prepared using glyceryl monooleyl ether (GME) by the modified film rehydration method. Hydrogenated lecithin (HL), 1,3-butylene glycol (1,3-BG), and Poloxamer 407 were used as additives. The prepared LCN formulations were evaluated based on particle size, small-angle X-ray diffraction (SAXS) analysis, (1)H- and (19)F-NMR spectra, and in vitro skin permeation across Yucatan micropig skin. The composition (weight percent) of the LCN formulations were GME-HL-1,3-BG (4 : 1 : 15), 4% GME-based LCN and GME-HL-1,3-BG (8 : 1 : 15), 8% GME-based LCN and their mean particle sizes were 130-175 nm. Flurbiprofen 5 and 10 mg was loaded into 4% GME-based LCN and 8% GME-based LCN systems, respectively. The results of SAXS and NMR suggested that both flurbiprofen-loaded formulations consist of particles with reverse type hexagonal phase (formation of hexosome) and flurbiprofen molecules were localized in the lipid domain through interaction of flurbiprofen with the lipid components. Flurbiprofen transport from the LCN systems across the Yucatan micropig skin was increased compared to flurbiprofen in citric buffer (pH=3.0). The 8% GME-based LCN systems was superior to the 4% GME-based LCN for flurbiprofen transport. Since the internal hexagonal phase in the 8% GME-based LCN systems had a higher degree of order compared to the 4% GME-based LCN in SAXS patterns, the 8% GME-based LCN system had a larger surface area, which might influence flurbiprofen permeation. These results indicated that the GME-based LCN system is effective in improving the skin permeation of flurbiprofen across the skin. PMID:25948327

  8. Conversion of glyceryl trinitrate to nitric oxide in tolerant and non-tolerant smooth muscle and endothelial cells.

    PubMed Central

    Salvemini, D.; Pistelli, A.; Vane, J.

    1993-01-01

    1. Exposure of smooth muscle cells (SMC) to glyceryl trinitrate (GTN, 75-600 microM) for 30 min led to a concentration-dependent increase in nitrite (NO2-), one of the breakdown products of nitric oxide (NO). This was not affected by 30 min pretreatment of the cells with 0.5 mM of sulphobromophthalein (SBP) an inhibitor of glutathione-S-transferase (GST), by metyrapone or SKF-525A inhibitors of cytochrome P450. These experiments were confirmed by organ bath studies using rabbit aortic strips denuded of endothelium and contracted with phenylephrine. Thus, a 30 min incubation of the strips with 0.5 mM SPB, metyrapone or SKF-525A did not affect the relaxations in response to GTN (10(-10)-10(-6) M). 2. Potentiation of the anti-platelet effect of GTN (44 microM) by endothelial cells (EC, 40 x 10(3) cells) was not affected by prior incubation of EC with SBP, metyrapone or SKF-525A (all at 0.5 mM). 3. Potentiation of the antiplatelet activity of GTN (11-352 microM) by small numbers of SMC (24 x 10(3) cells) or EC (40 x 10(3) cells) treated with indomethacin (10 microM) was attenuated when the SMC or EC were treated in culture with a high concentration of GTN (600 microM) for 18 h beforehand (referred to as 'tolerant' cells). In addition, tolerant SMC produced far less NO2- than non-tolerant SMC. 4. Exposure of non-tolerant SMC or EC (10(5) cells) to GTN (200 microM) for 3 min increased (3-4 fold) the levels of guanosine 3':5'-cyclic monophosphate (cyclic GMP).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8381319

  9. Assay of glyceryl trinitrate, isosorbide dinitrate, and their metabolites in plasma by large-bore capillary column gas-liquid chromatography.

    PubMed

    Booth, B P; Bennett, B M; Brien, J F; Elliott, D A; Marks, G S; McCans, J L; Nakatsu, K

    1990-11-01

    Two large-bore capillary columns, one with dimethyl polysiloxane (HP-1) as the stationary phase and the other with phenyl (50 per cent) methyl (50 per cent) polysiloxane (DB-17), were used to develop gas-liquid chromatographic (GLC) assays for measuring isosorbide dinitrate (ISDN), glyceryl trinitrate (GTN), and their metabolites. ISDN, isosorbide-2-mononitrate (2-ISMN), and isosorbide-5-mononitrate (5-ISMN) in plasma, ranging in concentration from 1 to 300 nM, and GTN, glyceryl-1,2-dinitrate (1,2-GDN), and glyceryl-1,3-dinitrate (1,3-GDN), ranging in concentration from 3 to 60 nM in plasma, were analysed on both columns. GLC analysis yielded baseline resolution of the analytes. The method using the dimethyl polysiloxane column gave a lower limit of detectability for GTN of 0.75 nM (signal/noise (s/n) = 2), and the procedure using the phenyl-methyl column provided a lower limit of detectability for ISDN of 81 pM (s/n = 2). The large-bore column GLC procedures exhibited shorter retention times for both ISDN and GTN than those previously reported for capillary-column assays. The chromatographic resolution of analytes and column efficiency of the large-bore capillary columns were comparable to the results previously found using capillary-column GC. The assays for ISDN and GTN have been shown to be appropriate for pharmacokinetic studies in volunteers and patients. We determined that the HP-1 column is appropriate for the analysis of GTN and metabolites, and the DB-17 column is suitable for analysis of ISDN and its metabolites. We conclude that the use of large-bore capillary columns provides rapid and reliable GLC assays for organic nitrates. PMID:2125512

  10. Ictal lack of binding to brain parenchyma suggests integrity of the blood-brain barrier for 11C-dihydroergotamine during glyceryl trinitrate-induced migraine.

    PubMed

    Schankin, Christoph J; Maniyar, Farooq H; Seo, Youngho; Kori, Shashidar; Eller, Michael; Chou, Denise E; Blecha, Joseph; Murphy, Stephanie T; Hawkins, Randall A; Sprenger, Till; VanBrocklin, Henry F; Goadsby, Peter J

    2016-07-01

    SEE DREIER DOI 101093/AWW112 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: For many decades a breakdown of the blood-brain barrier has been postulated to occur in migraine. Hypothetically this would facilitate access of medications, such as dihydroergotamine or triptans, to the brain despite physical properties otherwise restricting their entry. We studied the permeability of the blood-brain barrier in six migraineurs and six control subjects at rest and during acute glyceryl trinitrate-induced migraine attacks using positron emission tomography with the novel radioligand (11)C-dihydroergotamine, which is chemically identical to pharmacologically active dihydroergotamine. The influx rate constant Ki, average dynamic image and time activity curve were assessed using arterial blood sampling and served as measures for receptor binding and thus blood-brain barrier penetration. At rest, there was binding of (11)C-dihydroergotamine in the choroid plexus, pituitary gland, and venous sinuses as expected from the pharmacology of dihydroergotamine. However, there was no binding to the brain parenchyma, including the hippocampus, the area with the highest density of the highest-affinity dihydroergotamine receptors, and the raphe nuclei, a postulated brainstem site of action during migraine, suggesting that dihydroergotamine is not able to cross the blood-brain barrier. This binding pattern was identical in migraineurs during glyceryl trinitrate-induced migraine attacks as well as in matched control subjects. We conclude that (11)C-dihydroergotamine is unable to cross the blood-brain barrier interictally or ictally demonstrating that the blood-brain barrier remains tight for dihydroergotamine during acute glyceryl trinitrate-induced migraine attacks. PMID:27234268

  11. Ictal lack of binding to brain parenchyma suggests integrity of the blood–brain barrier for 11C-dihydroergotamine during glyceryl trinitrate-induced migraine

    PubMed Central

    Schankin, Christoph J.; Maniyar, Farooq H.; Seo, Youngho; Kori, Shashidar; Eller, Michael; Chou, Denise E.; Blecha, Joseph; Murphy, Stephanie T.; Hawkins, Randall A.; Sprenger, Till; VanBrocklin, Henry F.

    2016-01-01

    See Dreier (doi: 10.1093/aww112) for a scientific commentary on this article. For many decades a breakdown of the blood–brain barrier has been postulated to occur in migraine. Hypothetically this would facilitate access of medications, such as dihydroergotamine or triptans, to the brain despite physical properties otherwise restricting their entry. We studied the permeability of the blood–brain barrier in six migraineurs and six control subjects at rest and during acute glyceryl trinitrate-induced migraine attacks using positron emission tomography with the novel radioligand 11C-dihydroergotamine, which is chemically identical to pharmacologically active dihydroergotamine. The influx rate constant Ki, average dynamic image and time activity curve were assessed using arterial blood sampling and served as measures for receptor binding and thus blood–brain barrier penetration. At rest, there was binding of 11C-dihydroergotamine in the choroid plexus, pituitary gland, and venous sinuses as expected from the pharmacology of dihydroergotamine. However, there was no binding to the brain parenchyma, including the hippocampus, the area with the highest density of the highest-affinity dihydroergotamine receptors, and the raphe nuclei, a postulated brainstem site of action during migraine, suggesting that dihydroergotamine is not able to cross the blood–brain barrier. This binding pattern was identical in migraineurs during glyceryl trinitrate-induced migraine attacks as well as in matched control subjects. We conclude that 11C-dihydroergotamine is unable to cross the blood–brain barrier interictally or ictally demonstrating that the blood–brain barrier remains tight for dihydroergotamine during acute glyceryl trinitrate-induced migraine attacks. PMID:27234268

  12. Octadecyl-bonded silica membrane disk modified with Cyanex302 for pre-concentration and determination of iron in food products.

    PubMed

    Karve, Manjusha; Pandey, Durgesh

    2012-01-01

    A simple and rapid method using an octadecyl-bonded silica membrane disk impregnated with Cyanex302 is described for the pre-concentration and determination of iron. The influence of various parameters on sorption and elution of Fe(III) were systematically investigated. The sorption of Fe(III) at pH 3.2 was quantitative (99.3 +/- 1.1%). It was completely recovered using 20 mL 5.0 M HCI and determined by flame atomic absorption spectrometry. Breakthrough volume of the modified disk for Fe(III) was >2000 mL, pre-concentration factor was >100, and reusability up to 28 cycles. The LOD and LOQ for Fe(III) were 0.45 microg/L and 1.51 microg/L, respectively, while precision for its determination in terms of RSD was < or =2.1%. This method was applied for Fe(III) determination in milk, fortified flour, cocoa powder, tea, and black pepper. To validate the procedure, EPA Method Standard (QC standard 21) was analyzed for Fe(III). PMID:22970581

  13. Flame atomic absorption spectrometric determination of μg amounts of Fe (III) ions after solid phase extraction using modified octadecyl silica membrane disks

    NASA Astrophysics Data System (ADS)

    Mashhadizadeh, Mohammad Hossein; Azimi, Mansoureh Sadat; Pesteh, Mahnaz; Sheikhshoaei, Iran; Ardakani, Mohammad Mazloum; Karimi, Mohammad Ali

    2008-08-01

    A simple, rapid and reliable method has been developed to selectively separate and concentrate ultra trace amounts of Fe (III) ions from aqueous samples for the measurement by flame atomic absorption spectrometry (FAAS). By the passage of aqueous samples through an octadecyl silica membrane disk modified by a recently synthesized Schiff base (Bis-(4-nitro phenyl azo) salisilidine-1,3-diamino propane), Fe(III) ions adsorb quantitatively and most of matrix elements will pass through the disk to drain. The retained iron ions are then stripped from the disk by minimal amount of 0.1 mol l - 1 sulfuric acid as eluent. Extraction efficiency and the influence of pH, flow rates, amount of ligand, type and least amount of stripping acid as eluent were evaluated. The recovery of the iron from aqueous solution on the membrane disk modified with 3 mg Schiff's base was quantitative over pH 2-4.5. The linear dynamic range of the proposed method for Fe (III) ions was found in a wide concentration range of 0.20 (± 0.05)-680 (± 2) μg l - 1 . The detection limit and preconcentration factor of this solid phase extraction method were found 20.0 (± 0.7) ng l - 1 and 100 respectively. The reproducibility of the procedure is at the most 1.5%.

  14. Investigation of mussel adhesive protein adsorption on polystyrene and poly(octadecyl methacrylate) using angle dependent XPS, ATR-FTIR, and AFM

    SciTech Connect

    Baty, A.M.; Suci, P.A.; Tyler, B.J.; Geesey, G.G.

    1996-02-10

    Despite many years of research effort, the molecular interactions that are responsible for microbial adhesion and fouling of surfaces remain obscure. An understanding of these interactions would contribute to the development of surfaces that resist colonization of microorganisms. The irreversible adsorption of mussel adhesive proteins (MAP) from the marine mussel Mytilus edulis has been investigated on polystyrene (PS) and poly(octadecyl methacrylate) (POMA) surfaces using angle resolved X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometry, and atomic force microscopy (AFM). Angle resolved XPS was used to quantify the elemental composition with depth of the upper 90 {angstrom} of the surface, and AFM was used to obtain the surface topography. The adsorption pattern of MAP, revealed by AFM images, is distinctly different on the two polymer surfaces and suggests that the substratum influences protein adhesion. The depth profiles of MAP, obtained from angle resolved XPS, show differences in nitrogen composition with depth for MAP adsorbed to PS and POMA. Infrared spectra of hydrated adsorbed MAP revealed significant differences in the amide III region and in two bands which may originate from residues in the tandemly repeated sequences of MAP. This data demonstrates that the chemistry of the polymer film that is present at the protein-polymer interface can influence protein-protein and protein-surface interactions.

  15. Construction of a novel cationic polymeric liposomes formed from PEGlated octadecyl-quaternized lysine modified chitosan/cholesterol for enhancing storage stability and cellular uptake efficiency.

    PubMed

    Wang, Hanjie; Zhao, Peiqi; Liang, Xiaofei; Song, Tao; Gong, Xiaoqun; Niu, Ruifang; Chang, Jin

    2010-08-15

    The design and construction of delivery vectors with high stability and effective cellular uptake efficiency is very important. In this study, a novel polymeric liposomes (PLs) formed from PEGlated octadecyl-quaternized lysine modified chitosan (OQLCS) and cholesterol with higher size stability and cellular uptake efficiency has been synthesized successfully. Compared to conventional liposomes (CLs; phosphatidyl choline/cholesterol), the calcein-loaded PLs exhibited a multi-lamellar structure with homogenous size diameter (200 nm) and high calcein encapsulation efficiency (about 92%). PLs could be stored at different temperature (25, 4, and -20 degrees C) and different medium (deionized water, phosphate-buffered saline, and human plasma solution) for up to 4 weeks without significant size change. The spectrophotometer fluorometry analysis and the flow cytometry analysis indicated that in comparison with CL, PLs with positive zeta potential facilitates the uptake of calcein by MCF-7 tumor cells. The data suggests that PLs may provide a new method to overcome the stability and enhance the uptake efficiency of CLs. PMID:20506161

  16. Synthesis of a stationary phase based on silica modified with branched octadecyl groups by Michael addition and photoinduced thiol-yne click chemistry for the separation of basic compounds.

    PubMed

    Huang, Guang; Ou, Junjie; Wang, Hongwei; Ji, Yongsheng; Wan, Hao; Zhang, Zhang; Peng, Xiaojun; Zou, Hanfa

    2016-04-01

    A novel silica-based stationary phase with branched octadecyl groups was prepared by the sequential employment of the Michael addition reaction and photoinduced thiol-yne click chemistry with 3-aminopropyl-functionalized silica microspheres as the initial material. The resulting stationary phase denoted as SiO2 -N(C18)4 was characterized by elemental analysis, FTIR spectroscopy and Raman spectroscopy, demonstrating the existence of branched octadecyl groups in silica microspheres. The separations of benzene homologous compounds, acid compounds and amine analogues were conducted, demonstrating mixed-mode separation mechanism on SiO2 -N(C18)4 . Baseline separation of basic drugs mixture was acquired with the mobile phase of acetonitrile/H2 O (5%, v/v). SiO2 -N(C18)4 was further applied to separate Corydalis yanhusuo Wang water extracts, and more baseline separation peaks were obtained for SiO2 -N(C18)4 than those on Atlantis dC18 column. It can be expected that this new silica-based stationary phase will exhibit great potential in the analysis of basic compounds. PMID:26910263

  17. Eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-kappaB AND AP-1 through inhibition of MAPKS and AKT/IkappaBalpha signaling pathways in macrophages.

    PubMed

    Yeh, J L; Hsu, J H; Hong, Y S; Wu, J R; Liang, J C; Wu, B N; Chen, I J; Liou, S F

    2011-01-01

    Eugenol and isoeugenol, two components of clover oil, have been reported to possess several biomedical properties, such as anti-inflammatory, antimicrobial and antioxidant effects. This study aims to examine the anti-inflammatory effects of eugenol, isoeugenol and four of their derivatives on expression of inducible nitric oxide synthase (iNOS) activated by lipopolysaccharide (LPS) in mouse macrophages (RAW 264.7), and to investigate molecular mechanisms underlying these effects. We found that two derivatives, eugenolol and glyceryl-isoeugenol, had potent inhibitory effects on LPS-induced upregulation of nitrite levels, iNOS protein and iNOS mRNA. In addition, they both suppressed the release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) induced by LPS. Moreover, they both attenuated the DNA binding of NF-kB and AP-1, phosphorylation of inhibitory kB-alpha (IkB-alpha), and nuclear translocation of p65 protein induced by LPS. Finally, we demonstrated that glyceryl-isoeugenol suppressed the phosphorylation of ERK1/2, JNK and p38 MAPK, whereas eugenolol suppressed the phosphorylation of ERK1/2 and p38 MAPK. Taken together, these results suggest that that eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-kB and AP-1 through inhibition of MAPKs and Akt/IkB-alpha signaling pathways. Thus, this study implies that eugenolol and glyceryl-isoeugenol may provide therapeutic benefits for inflammatory diseases. PMID:21658309

  18. Glyceryl monooleate/poloxamer 407 cubic nanoparticles as oral drug delivery systems: I. In vitro evaluation and enhanced oral bioavailability of the poorly water-soluble drug simvastatin.

    PubMed

    Lai, Jie; Chen, Jianming; Lu, Yi; Sun, Jing; Hu, Fuqiang; Yin, Zongning; Wu, Wei

    2009-01-01

    Glyceryl monooleate (GMO)/poloxamer 407 cubic nanoparticles were investigated as potential oral drug delivery systems to enhance the bioavailability of the water-insoluble model drug simvastatin. The simvastatin-loaded cubic nanoparticles were prepared through fragmentation of the GMO/poloxamer 407 bulk cubic-phase gel using high-pressure homogenization. The internal structure of the cubic nanoparticles was identified by cryo-transmission electron microscopy. The mean diameter of the cubic nanoparticles varied within the range of 100-150 nm, and both GMO/poloxamer 407 ratio and theoretical drug loading had no significant effect on particle size and distribution. Almost complete entrapment with efficiency over 98% was achieved due to the high affinity of simvastatin to the hydrophobic regions of the cubic phase. Release of simvastatin from the cubic nanoparticles was limited both in 0.1 M hydrochloride solution containing 0.2% sodium lauryl sulfate and fasted-state simulated intestinal fluid with a total release of <3.0% at 10 h. Pharmacokinetic profiles in beagle dogs showed sustained plasma levels of simvastatin for cubic nanoparticles over 12 h. The relative oral bioavailability of simvastatin cubic nanoparticles calculated on the basis of area under the curve was 241% compared to simvastatin crystal powder. The enhancement of simvastatin bioavailability was possibly attributable to facilitated absorption by lipids in the formulation rather than improved release. PMID:19636709

  19. Riboflavin and vitamin E increase brain calcium and antioxidants, and microsomal calcium-ATP-ase values in rat headache models induced by glyceryl trinitrate.

    PubMed

    Bütün, Ayşe; Nazıroğlu, Mustafa; Demirci, Serpil; Çelik, Ömer; Uğuz, Abdulhadi Cihangir

    2015-04-01

    The essential use of riboflavin is the prevention of migraine headaches, although its effect on migraines is considered to be associated with the increased mitochondrial energy metabolism. Oxidative stress is also important in migraine pathophysiology. Vitamin E is a strong antioxidant in nature and its analgesic effect is not completely clear in migraines. The current study aimed to investigate the effects of glyceryl trinitrate (GTN)-sourced exogen nitric oxide (NO), in particular, and also riboflavin and/or vitamin E on involved in the headache model induced via GTN-sourced exogen NO on oxidative stress, total brain calcium levels, and microsomal membrane Ca(2+)-ATPase levels. GTN infusion is a reliable method to provoke migraine-like headaches in experimental animals and humans. GTN resulted in a significant increase in brain cortex and microsomal lipid peroxidation levels although brain calcium, vitamin A, vitamin C, and vitamin E, and brain microsomal-reduced glutathione (GSH), glutathione peroxidase (GSH-Px), and plasma-membrane Ca(2+)-ATPase values decreased through GTN. The lipid peroxidation, GSH, vitamin A, β-carotene, vitamin C, and vitamin E, and calcium concentrations, GSH-Px, and the Ca(2+)-ATPase activities were increased both by riboflavin and vitamin E treatments. Brain calcium and vitamin A concentrations increased through riboflavin only. In conclusion, riboflavin and vitamin E had a protective effect on the GTN-induced brain injury by inhibiting free radical production, regulation of calcium-dependent processes, and supporting the antioxidant redox system. However, the effects of vitamin E on the values seem more important than in riboflavin. PMID:25425044

  20. Protective effects of riboflavin and selenium on brain microsomal Ca2+-ATPase and oxidative damage caused by glyceryl trinitrate in a rat headache model.

    PubMed

    Nazıroğlu, Mustafa; Çelik, Ömer; Uğuz, Abdulhadi Cihangir; Bütün, Ayşe

    2015-03-01

    Migraine headaches are considered to be associated with increased mitochondrial energy metabolism. Mitochondrial oxidative stress is also important in migraine headache pathophysiology although riboflavin and selenium (Se) induced a modulator role on mitochondrial oxidative stress in the brain. The current study aimed to determine the effects of Se with/without riboflavin on the microsomal membrane Ca(2+)-ATPase (MMCA), lipid peroxidation, antioxidant, and electroencephalography (EEG) values in glyceryl trinitrate (GTN)-induced brain injury rats. Thirty-two rats were randomly divided into four groups. The first group was used as the control, and the second group was the GTN group. Se and Se plus oral riboflavin were administered to rats constituting the third and fourth groups for 10 days prior to GTN administration. The second, third, and fourth groups received GTN to induce headache. Ten hours after the administration of GTN, the EEG records and brain cortex samples were obtained for all groups. Brain cortex microsomes were obtained from the brain samples. The brain and microsomal lipid peroxidation levels were higher in the GTN group compared to the control group, whereas they were decreased by selenium and selenium + riboflavin treatments. Vitamin A, vitamin C, vitamin E, and reduced glutathione (GSH) concentrations of the brain and MMCA, GSH and glutathione peroxidase values of microsomes were decreased by the GTN administration, although the values and β-carotene concentrations were increased by Se and Se + riboflavin treatments. There was no significant change in EEG records of the four groups. In conclusion, Se with/without riboflavin administration protected against GTN-induced brain oxidative toxicity by inhibiting free radicals and the modulation of MMCA activity and supporting the antioxidant redox system. PMID:25492827

  1. Solid phase extraction of ultra traces mercury (II) using octadecyl silica membrane disks modified by 1,3-bis(2-ethoxyphenyl)triazene (EPT) ligand and determination by cold vapor atomic absorption spectrometry.

    PubMed

    Rofouei, Mohammad Kazem; Sabouri, Alireza; Ahmadalinezhad, Asieh; Ferdowsi, Hadis

    2011-09-15

    A facile and highly efficient method was developed for the preconcentration of the ultra trace amounts of mercury (II) ions. Octadecyl silica membrane disk was modified by the recently synthesized triazene ligand, 1,3-bis(2-ethoxyphenyl)triazene (EPT), and cold vapor atomic absorption spectrometry was used to determine the resultant preconcentrated Hg(II) ions. Solution studies with EPT and a series of metal ions were done in advance, and the results showed a strong affinity of EPT to the mercury ions. To perform solid phase extraction, various parameters such as pH of the sample, flow rates and the amount of the ligand were optimized. A linear calibration curve was obtained in the range of 0.02-1.90 μg L(-1) with r(2) = 0.9990 (n = 8), and the limit of detection (LOD) based on three times the standard deviation of the blank was 10.6 ng L(-1). The relative standard deviation (RSD) for the determination of 0.1 μg L(-1) Hg(II) found to be 2.9% while a RSD value of 1.1% was obtained for the determination of 1.0 μg L(-1) Hg(II) (n = 8). The preconcentration and improvement factors were 380 and 74, respectively. The newly developed method was successfully applied to the determination of mercury ions in real water samples. PMID:21782328

  2. Safety assessment for octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (CAS Reg. No. 2082-79-3) from use in food contact applications.

    PubMed

    Neal-Kluever, April P; Bailey, Allan B; Hatwell, Karen R

    2015-12-01

    Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS Reg. No. 2082-79-3), currently marketed as Irganox 1076 (I-76), is a sterically hindered phenolic antioxidant used in a variety of organic substrates, including those used in the manufacture of food contact articles. In 2012, the US Food and Drug Administration (USFDA), Office of Food Additive Safety (OFAS), initiated a post-market re-evaluation of the food contact applications of I-76. This project aimed to ensure that current dietary exposures from the use of I-76 in food contact articles are accurately captured and the safety assessment considered all relevant and available toxicological information. To accomplish these aims, the USFDA reviewed the available toxicological studies and chemistry information on food contact applications of I-76. Based on this in-depth analysis, a NOAEL of 64 mg/kg-bw/d (female rats) from a chronic rat study and a cumulative estimated dietary intake (CEDI) of 4.5 mg/p/d, was used to calculate a margin of exposure (MOE) of ∼850. We concluded that the previous and current exposure levels provide an adequate margin of safety (MOS) and remain protective of human health for the regulated uses. PMID:26482640

  3. Magnetic octadecyl-based matrix solid-phase dispersion coupled with gas chromatography with mass spectrometry in a proof-of-concept determination of multi-class pesticide residues in carrots.

    PubMed

    Binellas, Charalampos S; Stalikas, Constantine D

    2015-10-01

    A novel procedure is put forward based on the combination of the well-established matrix solid-phase dispersion and the magnetic and sorption properties of magnetic octadecyl in the presence of n-octanol and was employed in a proof-of-concept sample preparation and determination of several classes of pesticide residues in carrots. The procedure does not require the transfer of blend to cartridge and subsequent packing, nor any co-sorbent for extract clean up. The hydrophobic magnetic nanoparticles utilized as a sorbent, can be retrieved by n-octanol under the application of a magnetic field due to hydrophobic interactions. Elution of pesticide residues is then carried out with an organic solvent. A total of 26 pesticides were included in this procedure and the target compounds were analyzed using gas chromatography with mass spectrometry in the selective ion monitoring mode. The average extraction recoveries obtained from carrot samples fortified at three different concentrations (20, 50, and 500 μg/kg) were 77-107%. The estimated limits of quantitation for most target analytes were in the low μg/kg level. The study demonstrates that the proposed extraction procedure is simple and effective, avoiding a clean-up step for the sample preparation of vegetable. PMID:26293342

  4. Effect of Treatment Delay, Stroke Type, and Thrombolysis on the Effect of Glyceryl Trinitrate, a Nitric Oxide Donor, on Outcome after Acute Stroke: A Systematic Review and Meta-Analysis of Individual Patient from Randomised Trials

    PubMed Central

    Bath, Philip M.; Woodhouse, Lisa; Krishnan, Kailash; Anderson, Craig; Berge, Eivind; Ford, Gary A.; Robinson, Thompson G.; Saver, Jeffrey L.; Sprigg, Nikola; Wardlaw, Joanna M.; in Acute Stroke Collaboration (BASC), Blood pressure

    2016-01-01

    Background. Nitric oxide (NO) donors are a candidate treatment for acute stroke and two trials have suggested that they might improve outcome if administered within 4–6 hours of stroke onset. We assessed the safety and efficacy of NO donors using individual patient data (IPD) from completed trials. Methods. Randomised controlled trials of NO donors in patients with acute or subacute stroke were identified and IPD sought from the trialists. The effect of NO donor versus control on functional outcome was assessed using the modified Rankin scale (mRS) and death, by time to randomisation. Secondary outcomes included measures of disability, mood, and quality of life. Results. Five trials (4,197 participants) were identified, all involving glyceryl trinitrate (GTN). Compared with control, GTN lowered blood pressure by 7.4/3.3 mmHg. At day 90, GTN did not alter any clinical measures. However, in 312 patients randomised within 6 hours of stroke onset, GTN was associated with beneficial shifts in the mRS (odds ratio (OR) 0.52, 95% confidence interval (CI) 0.34–0.78) and reduced death (OR 0.32, 95% CI 0.14–0.78). Conclusions. NO donors do not alter outcome in patients with recent stroke. However, when administered within 6 hours, NO donors might improve outcomes in both ischaemic and haemorrhagic stroke. PMID:27190674

  5. 21 CFR 184.1324 - Glyceryl monostearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... glycerolysis of certain fats or oils that are derived from edible sources or by esterification, with glycerin, of stearic acid that is derived from edible sources. (b) The ingredient must be of a purity...

  6. 21 CFR 172.811 - Glyceryl tristearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... glycerol content: Not to exceed 0.5 percent. Unsaponifiable matter: Not to exceed 0.5 percent. Melting point (Class II): 69 °C-73 °C. (c) The additive is used or intended for use as follows when standards...

  7. 21 CFR 172.811 - Glyceryl tristearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... glycerol content: Not to exceed 0.5 percent. Unsaponifiable matter: Not to exceed 0.5 percent. Melting point (Class II): 69 °C-73 °C. (c) The additive is used or intended for use as follows when standards...

  8. 21 CFR 184.1328 - Glyceryl behenate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... acid made from glycerin and behenic acid (a saturated C22 fatty acid). The mixture contains... fatty acids. (2) Behenic acid. Between 80 and 90 percent of the total fatty acid content. (3) Acid...

  9. Quantification of ultra-trace amounts of copper by using off-line solid phase extraction-flame atomic absorption spectrometric determination through the octadecyl silica-bonded phase membrane (OSPM) C18 disks impregnated with 2,2'-[ethane-1,2-diylbis(thio)]dianiline.

    PubMed

    Mohammadhosseini, Majid; Soliemani, Esmaeil

    2014-07-01

    This study reports a very selective, easy, and precise method for rapid separation of trace amounts of copper in aqueous samples using octadecyl silica-bonded phase membrane disks modified by 2,2'-[ethane-1,2-diylbis(thio)]dianiline (EDTD) combined with flame atomic absorption spectrometric determination. In addition, the synthesis and spectral characterization of EDTD have been described in detail. All the affecting experimental variables such as pH, amount of modifier, eluent type, sample and eluent flow rate, interfering ions, and disk capacity were also investigated. The target analyte (trace copper) was quantitatively retained at pH = 4 and eluted with 6.0 mL of 0.5 M HNO3 at flow rates of 40 and 10 mL min−1 for analyte passage and elution steps, respectively, through the disks modified with 17.0 mg of EDTD. The proposed method also allows an enrichment factor of about 500 and has a detection limit of 0.005 ng mL−1. The method has been successfully applied for isolation and determination of copper in different water samples, peppers, and standard alloys. PMID:24659381

  10. In-vivo evaluation of clindamycin release from glyceryl monooleate-alginate microspheres by NIR spectroscopy.

    PubMed

    Mohamed, Amir Ibrahim; Ahmed, Osama A A; Amin, Suzan; Elkadi, Omar Anwar; Kassem, Mohamed A

    2015-10-15

    The purpose of this study was to use near-infrared (NIR) transmission spectroscopic technique to determine clindamycin plasma concentration after oral administration of clindamycin loaded GMO-alginate microspheres using rabbits as animal models. Lyophilized clindamycin-plasma standard samples at a concentration range of 0.001-10 μg/ml were prepared and analyzed by NIR and HPLC as a reference method. NIR calibration model was developed with partial least square (PLS) regression analysis. Then, a single dose in-vivo evaluation was carried out and clindamycin-plasma concentration was estimated by NIR. Over 24 h time period, the pharmacokinetic parameters of clindamycin were calculated for the clindamycin loaded GMO-alginate microspheres (F3) and alginate microspheres (F2), and compared with the plain drug (F1). PLS calibration model with 7-principal components (PC), and 8000-9200 cm(-1) spectral range shows a good correlation between HPLC and NIR values with root mean square error of cross validation (RMSECV), root mean square error of prediction (RMSEP), and calibration coefficient (R(2)) values of 0.245, 1.164, and 0.9753, respectively, which suggests that NIR transmission technique can be used for drug-plasma analysis without any extraction procedure. F3 microspheres exhibited controlled and prolonged absorption Tmax of 4.0 vs. 1.0 and 0.5 h; Cmax of 2.37±0.3 vs. 3.81±0.8 and 5.43±0.7 μg/ml for F2 and F1, respectively. These results suggest that the combination of GMO and alginate (1:4 w/w) could be successfully employed for once daily clindamycin microspheres formulation which confirmed by low Cmax and high Tmax values. PMID:26276253

  11. Surface components of chylomicrons from rats fed glyceryl or alkyl esters of fatty acids: minor components.

    PubMed

    Yang, L Y; Kuksis, A; Myher, J J; Pang, H

    1992-08-01

    The lipid class, fatty acid and molecular species composition of the minor polar surface components of rat lymph chylomicrons were determined during absorption of menhaden oil and corn oil or of the corresponding fatty acid ethyl esters. In addition to the previously reported minor polar lipids (sphingomyelin, phosphatidylserine, phosphatidylinositol, phosphatidic acid and lysophosphatidylcholine), we identified phosphatidylglycerol, dimethylphosphatidylethanolamine, ceramide and cholesteryl sulfate in the chylomicrons from both oil and ester feeding. The dietary fatty acids were found to be incorporated to a variable extent into the different phospholipid classes, the proportions of which remained the same during both types of feeding. No evidence was obtained for the presence of the minor glycerophospholipids characteristic of the lysosomal membranes (e.g., bis-phosphatidic, lysobisphosphatidic and semilysobis-phosphatidic acids), although special efforts were made to identify them. These results indicate that the chylomicrons arising from the monoacylglycerol and phosphatidic acid pathways of triacylglycerol biosynthesis become enveloped in closely similar monolayers of phospholipids. Hence, all triacylglycerols may be secreted from the villus cells via a common mechanism as suggested by the previously demonstrated convergence (at the 2-monoacylglycerol stage) of the monoacylglycerol and the phosphatidic acid pathways of mucosal triacylglycerol formation [Yang, Y.L., and Kuksis, A. (1991) J. Lipid Res. 32, 1173-1186]. PMID:1406072

  12. Treatment of Xerosis with a Topical Formulation Containing Glyceryl Glucoside, Natural Moisturizing Factors, and Ceramide

    PubMed Central

    Kausch, Martina; Rippke, Frank; Schoelermann, Andrea M.; Filbry, Alexander W.

    2012-01-01

    Objective: To assess the effects of Light Formulation, an oil-in-water emulsion, and Rich Formulation, a water-in-oil emulsion, for the treatment of xerosis. Design: Two double-blind, vehicle-controlled trials (both formulations); a double-blind, randomized regression study (Rich Formulation); and a single-blind tolerability study (Light Formulation). The two formulations were applied twice daily for two weeks, for five days in the regression study, and twice daily for two weeks in the tolerability study. Setting: Studies were conducted during winter in Hamburg, Germany. Participants: A total of 169 subjects were enrolled and 154 completed the studies. The majority were between 50 and 80 years of age, women, all with very dry skin. One withdrew because of an incompatibility reaction that reoccurred with the subject's own body lotion after sun exposure. Measurements: Skin hydration and skin barrier function with both formulations over two weeks, long-term moisturization effect after discontinuation of Rich Formulation, and symptom improvement and skin tolerability with Light Formulation. Results: Vehicle-controlled studies of Light and Rich Formulations demonstrated significantly improved hydration at Weeks 1 and 2 versus the untreated site and vehicles, and significantly reduced transepidermal water loss versus untreated site and basic vehicle. Both products significantly decreased visible dryness and tactile roughness. In the regression study, Rich Formulation maintained significant moisturization six days after treatment discontinuation. Light Formulation reduced symptoms of itching, burning, tightness, tingling, and feeling of dryness. Conclusion: These formulations represent a new approach for the treatment of xerosis by addressing multiple key deficiencies in skin hydration. PMID:22916312

  13. Effect of drug solubility and different excipients on floating behaviour and release from glyceryl monooleate matrices.

    PubMed

    Kumar M, Kiran; Shah, Manish H; Ketkar, Anant; Mahadik, K R; Paradkar, Anant

    2004-03-19

    Glycerol monooleate (GMO) matrix was found to be a gastro-retentive carrier system suitable for both polar and as well as non-polar drugs. Chlorpheniramine maleate (CPM) and diazepam (DZP) were used as model drugs. Effect of PEG 4000, PEG 10000, and stearic acid on floatability and release profile was studied. Water uptake increased with increase in the loading of polar drug (CPM) and decreased with non-polar drug (DZP). Similar effect was found to occur in case of drug release. PEGs increased the release up to certain concentration and decreased thereafter. Drug release decreased linearly with concentration of stearic acid. The type and extent of mesophases formed were significantly affected by the nature of drug, excipients and their concentration. Thus the selection of suitable excipients depending on polarity of drug, could help to modulate the floatability and release profile from GMO matrices. PMID:15019078

  14. Glycerophosphocholine Metabolism in Higher Plant Cells. Evidence of a New Glyceryl-Phosphodiester Phosphodiesterase

    PubMed Central

    van der Rest, Benoît; Boisson, Anne-Marie; Gout, Elisabeth; Bligny, Richard; Douce, Roland

    2002-01-01

    Glycerophosphocholine (GroPCho) is a diester that accumulates in different physiological processes leading to phospholipid remodeling. However, very little is known about its metabolism in higher plant cells. 31P-Nuclear magnetic resonance spectroscopy and biochemical analyses performed on carrot (Daucus carota) cells fed with GroPCho revealed the existence of an extracellular GroPCho phosphodiesterase. This enzymatic activity splits GroPCho into sn-glycerol-3-phosphate and free choline. In vivo, sn-glycerol-3-phosphate is further hydrolyzed into glycerol and inorganic phosphate by acid phosphatase. We visualized the incorporation and the compartmentation of choline and observed that the major choline pool was phosphorylated and accumulated in the cytosol, whereas a minor fraction was incorporated in the vacuole as free choline. Isolation of plasma membranes, culture medium, and cell wall proteins enabled us to localize this phosphodiesterase activity on the cell wall. We also report the existence of an intracellular glycerophosphodiesterase. This second activity is localized in the vacuole and hydrolyzes GroPCho in a similar fashion to the cell wall phosphodiesterase. Both extra- and intracellular phosphodiesterases are widespread among different plant species and are often enhanced during phosphate deprivation. Finally, competition experiments on the extracellular phosphodiesterase suggested a specificity for glycerophosphodiesters (apparent Km of 50 μm), which distinguishes it from other phosphodiesterases previously described in the literature. PMID:12226504

  15. 21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860 and/or oleic acid derived from tall oil fatty...

  16. 21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860 and/or oleic acid derived from tall oil fatty...

  17. 21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860 and/or oleic acid derived from tall oil fatty...

  18. 21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860 and/or oleic acid derived from tall oil fatty...

  19. Differential effects of free and liposome-associated 1-O-octadecyl-2-O-methylglycerophosphocholine on protein kinase C.

    PubMed

    Spiegel, S; Olah, Z; Cuvillier, O; Edsall, L C; Janoff, A S

    1999-07-01

    Incorporation of ET-18-OCH3 into well-characterized liposomes known as ELL-12 has eliminated its gastrointestinal and hemolytic toxicity without loss of growth inhibiting activity. ET-18-OCH3, but not ELL-12, blunted the increase in membrane protein kinase C (PKC) activity induced by 12-O-tetradecanoylphorbol 13-myristate (TPA) and markedly reduced levels of PKC alpha in NIH 3T3 fibroblasts. Furthermore, prolonged treatment with ELL-12 neither inhibited TPA-induced translocations of PKC alpha and PKC delta to the particulate fraction nor caused down-regulation, and did not affect the cellular distribution of TPA-insensitive PKC zeta. In Jurkat T cells, where ELL-12 markedly induced apoptosis that was blocked by an inhibitor of caspase-3-like activities, it had no effect on PKC activity or translocation induced by TPA. Thus, it seems unlikely that PKC is involved in the therapeutic effects of ELL-12. PMID:10413111

  20. Effect of ethylcellulose and propylene glycol on the controlled-release performance of glyceryl monooleate-mertronidazole periodontal gel.

    PubMed

    Sallam, Al-Sayed; Hamudi, Firas Falih; Khalil, Enam Ayoub

    2015-03-01

    Controlled-release metronidazole, mucoadhesive gel proposed as a drug-delivery system for periodontal application was developed and characterized. The system was based on a mixture of glycerylmonooleate (GMO) and ethylcellulose (EC). The mechanism of release depends: firstly, on the ability of GMO to form a viscous liquid crystalline mesophases and secondly on the solubilized EC to form a hydrophobic network when the mixture comes into contact with water resulting in sustaining the release of the drug. Ethylcellulose dissolved in GMO had a profound influence on the rate of drug release, reduced the initial drug release and prolonged the sustained release of metronidazole. Propylene glycol (PG) was added to increase the solubility of the drug and water was added with PG to control the viscosity. A controlled release formulation containing w/w, 20% metronidazole, 10% PG, 5% water and 65% GMO that contains 7% EC was found to be mucoadhesive, easily injectable at room temperature, and to follow Fickian diffusion release mechanism. When the drug loading was increased the drug release was accelerated, and the mechanism followed anomalous controlled-release mechanism. Stability studies indicated that the formulation should be stored at 4 °C in a dark place. PMID:24262092

  1. Solid-phase extraction and atomic absorption spectrometric determination of cobalt using an octadecyl bonded silica membrane disk modified with Cyanex 272.

    PubMed

    Karve, Manjusha; Gholave, Jayram V

    2011-01-01

    A simple SPE method for determination of cobalt(II) using a C18 bonded silica membrane disk impregnated with Cyanex 272 has been developed. Cobalt(II) was quantitatively sorbed at pH 6.0 from a sample solution and eluted using 10.0 mL 1.0 M HNO3 prior to its flame atomic absorption spectrometric determination. The influence of eluting agents, the minimum volume and maximum flow rate of the eluent, and interfering ions on cobalt(II) was studied. The method developed for cobalt(II) had an LOD of 1.4 microg/L, and a preconcentration factor > 200 with an RSD of 0.6%. The reusability of the modified disk was for 40 cycles. The method was applied for the determination of cobalt in certified samples, urine, and industrial sludge samples. PMID:21563699

  2. Catalysis at the toulene/water interface: Octadecyl immobilized H-ZSM-5 catalyst promoted hydrolysis of water-insoluble esters

    SciTech Connect

    Ogawa, Haruo; Koh, Tensai ); Taya, Kazuo ); Chihara, Teiji , Wako )

    1994-08-01

    Octadecyltrichorosilane-treated H-ZSM-5, abbreviated as H-ZSM-5-C[sub 18] resulted in an effective catalyst for the hydrolysis of water-insoluble esters in toluene-water solvent system. These floated at the interface of the two liquids. The H-ZSM-5-C[sub 18] catalyst showed ca. 60 times the activity of H-ZSM-5 for the hydrolysis of dodecyl acetate. Acid strength of H-ZSM-5 in water (-5.6 < Ho [<=] -3.0) was maintained even after the treatment with octadecyltrichlorosilane. The treatment renders H-ZSM-5 lipophylicity and provides a quasi-lipid phase on the surface. The shape-selective properties of H-ZSM-5-C[sub 18] catalyst were observed for the hydrolysis of aliphatic esters with straight chains. 17 refs., 9 figs., 6 tabs.

  3. Fabrication and spectroscopic properties of Langmuir Blodgett films of novel zinc complexes with long chain mono (hexadecyl, octadecyl, eicosyl, and docosyl) phthalate

    NASA Astrophysics Data System (ADS)

    Xu, Bing; Yan, Bing

    2007-08-01

    In this paper, some novel long chain amphiphillic monoester molecules were designed to afford double functions: film-formation and luminescent sensitization. Subsequently, organized molecular films of zinc complexes with these functional ligands formulated as ZnL 2 were fabricated by the Langmuir-Blodgett film (LB) technology, where L denoted the long chain carboxylic ligands monohexadecyl phthalate (16-Phth), monooctadecyl phthalate (18-Phth), monoeicosyl phthalate (20-Phth) and monodocosyl phthalate (22-Phth). The average molecular area was obtained according to the π-A isotherms. The layer structure of the LB films was demonstrated by low-angle X-ray diffraction and the average layer spacing were obtained according to the Bragg equation. The characteristic luminescence behaviors of LB films have been discussed compared with those of their corresponding solid complexes.

  4. Liquid Crystalline Nanoparticles as an Ophthalmic Delivery System for Tetrandrine: Development, Characterization, and In Vitro and In Vivo Evaluation.

    PubMed

    Liu, Rui; Wang, Shuangshuang; Fang, Shiming; Wang, Jialu; Chen, Jingjing; Huang, Xingguo; He, Xin; Liu, Changxiao

    2016-12-01

    The purpose of this study was to develop novel liquid crystalline nanoparticles (LCNPs) that display improved pre-ocular residence time and ocular bioavailability and that can be used as an ophthalmic delivery system for tetrandrine (TET). The delivery system consisted of three primary components, including glyceryl monoolein, poloxamer 407, and water, and two secondary components, including Gelucire 44/14 and amphipathic octadecyl-quaternized carboxymethyl chitosan. The amount of TET, the amount of glyceryl monoolein, and the ratio of poloxamer 407 to glyceryl monoolein were selected as the factors that were used to optimize the dependent variables, which included encapsulation efficiency and drug loading. A three-factor, five-level central composite design was constructed to optimize the formulation. TET-loaded LCNPs (TET-LCNPs) were characterized to determine their particle size, zeta potential, entrapment efficiency, drug loading capacity, particle morphology, inner crystalline structure, and in vitro drug release profile. Corneal permeation in excised rabbit corneas was evaluated. Pre-ocular retention was determined using a noninvasive fluorescence imaging system. Finally, pharmacokinetic study in the aqueous humor was performed by microdialysis technique. The optimal formulation had a mean particle size of 170.0 ± 13.34 nm, a homogeneous distribution with polydispersity index of 0.166 ± 0.02, a positive surface charge with a zeta potential of 29.3 ± 1.25 mV, a high entrapment efficiency of 95.46 ± 4.13 %, and a drug loading rate of 1.63 ± 0.07 %. Transmission electron microscopy showed spherical particles that had smooth surfaces. Small-angle X-ray scattering profiles revealed an inverted hexagonal phase. The in vitro release assays showed a sustained drug release profile. A corneal permeation study showed that the apparent permeability coefficient of the optimal formulation was 2.03-fold higher than that of the TET solution. Pre

  5. Liquid Crystalline Nanoparticles as an Ophthalmic Delivery System for Tetrandrine: Development, Characterization, and In Vitro and In Vivo Evaluation

    NASA Astrophysics Data System (ADS)

    Liu, Rui; Wang, Shuangshuang; Fang, Shiming; Wang, Jialu; Chen, Jingjing; Huang, Xingguo; He, Xin; Liu, Changxiao

    2016-05-01

    The purpose of this study was to develop novel liquid crystalline nanoparticles (LCNPs) that display improved pre-ocular residence time and ocular bioavailability and that can be used as an ophthalmic delivery system for tetrandrine (TET). The delivery system consisted of three primary components, including glyceryl monoolein, poloxamer 407, and water, and two secondary components, including Gelucire 44/14 and amphipathic octadecyl-quaternized carboxymethyl chitosan. The amount of TET, the amount of glyceryl monoolein, and the ratio of poloxamer 407 to glyceryl monoolein were selected as the factors that were used to optimize the dependent variables, which included encapsulation efficiency and drug loading. A three-factor, five-level central composite design was constructed to optimize the formulation. TET-loaded LCNPs (TET-LCNPs) were characterized to determine their particle size, zeta potential, entrapment efficiency, drug loading capacity, particle morphology, inner crystalline structure, and in vitro drug release profile. Corneal permeation in excised rabbit corneas was evaluated. Pre-ocular retention was determined using a noninvasive fluorescence imaging system. Finally, pharmacokinetic study in the aqueous humor was performed by microdialysis technique. The optimal formulation had a mean particle size of 170.0 ± 13.34 nm, a homogeneous distribution with polydispersity index of 0.166 ± 0.02, a positive surface charge with a zeta potential of 29.3 ± 1.25 mV, a high entrapment efficiency of 95.46 ± 4.13 %, and a drug loading rate of 1.63 ± 0.07 %. Transmission electron microscopy showed spherical particles that had smooth surfaces. Small-angle X-ray scattering profiles revealed an inverted hexagonal phase. The in vitro release assays showed a sustained drug release profile. A corneal permeation study showed that the apparent permeability coefficient of the optimal formulation was 2.03-fold higher than that of the TET solution. Pre-ocular retention

  6. Stable isotope-assisted LC-MS/MS monitoring of glyceryl trinitrate bioactivation in a cell culture model of nitrate tolerance.

    PubMed

    Axton, Elizabeth R; Hardardt, Elizabeth A; Stevens, Jan F

    2016-04-15

    The nitric oxide (NO) metabolites nitrite (NO2(-)) and nitrate (NO3(-)) can be quantified as an endpoint of endothelial function. We developed a LC-MS/MS method of measuring nitrite and nitrate isotopologues, which has a lower limit of quantification (LLOQ) of 1 nM. This method allows for isotopic labeling to differentiate newly formed nitrite and nitrate from nanomolar to micromolar background levels of nitrite and nitrate in biological matrices. This method utilizes 2,3-diaminonaphthalene (DAN) derivatization, which reacts with nitrite under acidic conditions to produce 2,3-naphthotriazole (NAT). NAT was chromatographically separated on a Shimadzu LC System with an Agilent Extend-C18 5 μm 2.1 × 150 mm column and detected using a multiple reaction monitoring (MRM) method on an ABSciex 3200 QTRAP mass spectrometer operated in positive mode. Mass spectrometry allows for the quantification of (14)N-NAT (m/z 170.1) and (15)N-NAT (m/z 171.1). Both nitrite and nitrate demonstrated a linear detector response (1 nM - 10 μM, 1 nM - 100 nM, respectively), and were unaffected by common interferences (Dulbecco's Modified Eagle Medium (DMEM), fetal bovine serum (FBS), phenol red, and NADPH). This method requires minimal sample preparation, making it ideal for most biological applications. We applied this method to develop a cell culture model to study the development of nitrate tolerance in human endothelial cells (EA.hy926). PMID:26796748

  7. 21 CFR 582.60 - Synthetic flavoring substances and adjuvants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...). Geranyl acetate (geraniol acetate). Glycerol (glyceryl) tributyrate (tributyrin, butyrin). Limonene (d-, l... (benzoic aldehyde). N-Butyric acid (butanoic acid). d- or l-Carvone (carvol). Cinnamaldehyde...

  8. 21 CFR 582.60 - Synthetic flavoring substances and adjuvants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...). Geranyl acetate (geraniol acetate). Glycerol (glyceryl) tributyrate (tributyrin, butyrin). Limonene (d-, l... (benzoic aldehyde). N-Butyric acid (butanoic acid). d- or l-Carvone (carvol). Cinnamaldehyde...

  9. 21 CFR 582.60 - Synthetic flavoring substances and adjuvants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...). Geranyl acetate (geraniol acetate). Glycerol (glyceryl) tributyrate (tributyrin, butyrin). Limonene (d-, l... (benzoic aldehyde). N-Butyric acid (butanoic acid). d- or l-Carvone (carvol). Cinnamaldehyde...

  10. 21 CFR 582.60 - Synthetic flavoring substances and adjuvants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...). Geranyl acetate (geraniol acetate). Glycerol (glyceryl) tributyrate (tributyrin, butyrin). Limonene (d-, l... (benzoic aldehyde). N-Butyric acid (butanoic acid). d- or l-Carvone (carvol). Cinnamaldehyde...

  11. 21 CFR 582.60 - Synthetic flavoring substances and adjuvants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...). Geranyl acetate (geraniol acetate). Glycerol (glyceryl) tributyrate (tributyrin, butyrin). Limonene (d-, l... (benzoic aldehyde). N-Butyric acid (butanoic acid). d- or l-Carvone (carvol). Cinnamaldehyde...

  12. 5-HIAA

    MedlinePlus

    HIAA; 5-hydroxyindole acetic acid; Serotonin metabolite ... interfere with the test. Medicines that can increase 5-HIAA measurements include acetaminophen (Tylenol), acetanilide, phenacetin, glyceryl ...

  13. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) The acrylate ester copolymer is a fully polymerized copolymer of ethyl acrylate, methyl methacrylate... emulsion defoamer. Disodium hydrogen phosphate Do. Formaldehyde Glyceryl monostearate Methyl...

  14. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... polymerized copolymer of ethyl acrylate, methyl methacrylate, and methacrylic acid applied in emulsion form to... Glyceryl monostearate Methyl cellulose Mineral oil Paraffin wax Potassium hydroxide Potassium...

  15. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) The acrylate ester copolymer is a fully polymerized copolymer of ethyl acrylate, methyl methacrylate... emulsion defoamer. Disodium hydrogen phosphate Do. Formaldehyde Glyceryl monostearate Methyl...

  16. 21 CFR 172.832 - Monoglyceride citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN... glyceryl monooleate and its citric acid monoester manufactured by the reaction of glyceryl monooleate with... addition to oils and fats whereby the additive does not exceed 200 parts per million of the combined...

  17. 21 CFR 172.832 - Monoglyceride citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN... glyceryl monooleate and its citric acid monoester manufactured by the reaction of glyceryl monooleate with... addition to oils and fats whereby the additive does not exceed 200 parts per million of the combined...

  18. 21 CFR 172.832 - Monoglyceride citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN... glyceryl monooleate and its citric acid monoester manufactured by the reaction of glyceryl monooleate with... addition to oils and fats whereby the additive does not exceed 200 parts per million of the combined...

  19. Microstructure of Hairy-Rod Polymers at the Air-Water Interface

    NASA Astrophysics Data System (ADS)

    Chien, B. T.; Riou, S. A.; Su, Z.; Hsu, S. L.

    1997-03-01

    To better understand the role of long flexible side groups on the microstructure of "hairy-rod" polymer thin films, a series of poly(γ-methyl-L-glutamate-co-γ-n-octadecyl-L- glutamate) of varying degree copolymerization has been investigated at the air-water interface by external reflectance infrared spectroscopy. Coupled with a Langmuir trough, the microstructure of the monolayer films was charaterized directly at the air-water interface as a function of varying surface packing density. The conformational order of the n-octadecyl side groups was subsequently shown to vary strongly as a function of n-octadecyl side group content as well as surface packing density. When conformationally disordered, the n-octadecyl side groups could be likened to that of a Rsolvent-likeS matrix for the rigid- rod main chains in the plane of the interface. By controlling the conformational order and therefore the Rsolvent-likeS character of the n-octadecyl side groups, it was possible to control an in-plane orientation of the rigid-rod main chains relative to that of the compression axis of the Langmuir trough. The orientation of the n- octadecyl side groups out of the plane of the air-water interface was also determined.

  20. The adjuvant effect of stearyl tyrosine on a recombinant subunit hepatitis B surface antigen.

    PubMed

    Nixon-George, A; Moran, T; Dionne, G; Penney, C L; Lafleur, D; Bona, C A

    1990-06-15

    We describe the enhancement of the antibody response against hepatitis B surface Ag by octadecyl L-tyrosine, a synthetic adjuvant designed to exert its adjuvant effect in a manner similar to that of alum because it binds soluble Ag and releases it slowly from the site of injection. Our data demonstrate that octadecyl L-tyrosine showed a significant enhancement of the antihepatitis B surface Ag response compared to that of alum in the secondary response. The most striking difference between octadecyl L-tyrosine and alum in the antihepatitis B surface Ag antibody response was the absence of IgE-specific antibodies subsequent to immunization of the Ag in octadecyl L-tyrosine. Both the optical isomers of the octadecyl esters of tyrosine were adjuvant active, however, the racemic mixture showed a significantly lowe adjuvant activity. This adjuvant has great potential to be used in humans because it is devoid of side effects as assessed by the lack of acute and chronic toxicity in mice and rats, pyrogenicity in rabbits, formation of granuloma in cats, and adjuvant arthritis in rats. PMID:2351829

  1. Immobilization of Yarrowia lipolytica Lipase—A Comparison of Stability of Physical Adsorption and Covalent Attachment Techniques

    NASA Astrophysics Data System (ADS)

    Cunha, Aline G.; Fernández-Lorente, Gloria; Bevilaqua, Juliana V.; Destain, Jacqueline; Paiva, Lúcia M. C.; Freire, Denise M. G.; Fernández-Lafuente, Roberto; Guisán, Jose M.

    Lipase immobilization offers unique advantages in terms of better process control, enhanced stability, predictable decay rates and improved economics. This work evaluated the immobilization of a highly active Yarrowia lipolytica lipase (YLL) by physical adsorption and covalent attachment. The enzyme was adsorbed on octyl-agarose and octadecyl-sepabeads supports by hydrophobic adsorption at low ionic strength and on MANAE-agarose support by ionic adsorption. CNBr-agarose was used as support for the covalent attachment immobilization. Immobilization yields of 71, 90 and 97% were obtained when Y. lipolytica lipase was immobilized into octyl-agarose, octadecyl-sepabeads and MANAE-agarose, respectively. However, the activity retention was lower (34% for octyl-agarose, 50% for octadecyl-sepabeads and 61% for MANAE-agarose), indicating that the immobilized lipase lost activity during immobilization procedures. Furthermore, immobilization by covalent attachment led to complete enzyme inactivation. Thermal deactivation was studied at a temperature range from 25 to 45°C and pH varying from 5.0 to 9.0 and revealed that the hydrophobic adsorption on octadecyl-sepabeads produced an appreciable stabilization of the biocatalyst. The octadecyl-sepabeads biocatalyst was almost tenfold more stable than free lipase, and its thermal deactivation profile was also modified. On the other hand, the Y. lipolytica lipase immobilized on octyl-agarose and MANAE-agarose supports presented low stability, even less than the free enzyme.

  2. [Preparation and properties of organobentonites].

    PubMed

    Zheng, Yu-Ying; Zhang, Han-Hui; Cai, Wei-Long; Fu, Ming-Lian; Wang, Liang-En

    2005-01-01

    The chemistry organobentonites were synthesized by means of the ionexchange reaction between single-octadecyl trimethyl ammonium chloride(SOAC), di-octadecyl dimethyl ammonium chloride (DOAC) , tri-octadecyl methylammonium chloride (TOAC) quaternary ammonium salts and sodium base bentonies, respectively. The authors used FTIR, X-ray diffraction diagram and DSC thermograms to characterate the structure of the modified bentonites, and discussed the effect of different quaternary ammonium salt on the properties of organobentonites. The results showed that ion of the surfactants had entered into the chip layer of the bentonites, and changed the hydrophilic environment of the chip layer into hydrophobic environment and increased the distance among the chip layer, all of these had laid a base for the preparation of the nanometer composite material of high polymer/bentonite. PMID:15852820

  3. S-nitrosothiols as vasodilators: implications regarding tolerance to nitric oxide-containing vasodilators.

    PubMed Central

    Henry, P. J.; Drummer, O. H.; Horowitz, J. D.

    1989-01-01

    1. The formation of an S-nitrosothiol compound, S-nitroso-N-acetylcysteine (SNAC) has recently been proposed to mediate the augmentation of the anti-aggregatory and haemodynamic effects of glyceryl trinitrate observed in the presence of N-acetylcysteine. This study investigated the effects on an isolated coronary artery preparation of acute and prolonged exposure to S-nitrosothiol compounds and nitric oxide (NO). 2. Single doses of NO and of the S-nitrosothiol compounds, SNAC and S-nitroso-N-acetyl-penicillamine (SNAP), induced rapid, but transient, relaxations in U46619-contracted bovine isolated coronary artery rings. Peak relaxation responses to SNAP and NO were attenuated in the presence of N-acetylcysteine, cysteine, ascorbic acid and methylene blue. The duration of the relaxation responses to SNAC was two to three times longer than those to SNAP and NO. In the presence of N-acetylcysteine (but not cysteine, ascorbic acid or methylene blue) the duration of the relaxation responses to SNAP and NO (but not to SNAC) was markedly increased. H.p.l.c. assay confirmed that, in the presence of N-acetylcysteine, SNAP and, to a lesser degree, NO were converted to the relatively more stable and longer acting vasodilator, SNAC. 3. When compared to control rings, coronary artery rings superfused with glyceryl trinitrate were subsequently markedly less responsive to the vasodilator actions of glyceryl trinitrate, whereas responsiveness to SNAC or NO was only marginally reduced. On the other hand, coronary artery rings superfused with SNAC or NO were subsequently less responsive to glyceryl trinitrate, SNAC and NO. Thus prolonged vascular exposure to SNAC or NO induced a form of tolerance different from that induced with glyceryl trinitrate and which is possibly associated with impaired guanylate cyclase activity. 4. Coronary artery rings superfused with NO were markedly less responsive to glyceryl trinitrate and NO, whereas responses to the endothelium-dependent vasodilator

  4. Incorporation of phosphatidylglycerol into murein lipoprotein in intact cells of Salmonella typhimurium by phospholipid vesicle fusion.

    PubMed Central

    Chattopadhyay, P K; Lai, J S; Wu, H C

    1979-01-01

    The biosynthesis of the diglyceride moiety of murein lipoprotein was studied by fusion of labeled phospholipid vesicles with intact cells of Salmonella typhimurium. Phosphatidylglycerol was found to be an excellent donor for the glyceryl moiety in lipoprotein, whereas phosphatidylethanolamine and cardiolipin were not. The incorporation of radioactivity from monoacyl-phosphatidylglycerol into lipoprotein can be attributed to its conversion to phosphatidylglycerol. The results strongly support our hypothesis that the glyceryl residue covalently linked to murein lipoprotein is derived from the nonacylated glycerol moiety of phosphatidylglycerol. PMID:368018

  5. In vitro drug release mechanism and drug loading studies of cubic phase gels.

    PubMed

    Lara, Marilisa G; Bentley, M Vitória L B; Collett, John H

    2005-04-11

    Glyceryl monooleate/water cubic phase systems were investigated as drug delivery systems, using salicylic acid as a model drug. The liquid crystalline phases formed by the glyceryl monooleate (GMO)/water systems were characterized by polarizing microscopy. In vitro drug release studies were performed and the influences of initial water content, swelling and drug loading on the drug release properties were evaluated. Water uptake followed second-order swelling kinetics. In vitro release profiles showed Fickian diffusion control and were independent on the initial water content and drug loading, suggesting GMO cubic phase gels suitability for use as drug delivery system. PMID:15778062

  6. Effect of the physicochemical parameters of benzimidazole molecules on their retention by a nonpolar sorbent from an aqueous acetonitrile solution

    NASA Astrophysics Data System (ADS)

    Shafigulin, R. V.; Safonova, I. A.; Bulanova, A. V.

    2015-09-01

    The effect of the structure of benzimidazoles on their chromatographic retention on octadecyl silica gel from an aqueous acetonitrile eluent was studied. One- and many-parameter correlation equations were obtained by linear regression analysis, and their prognostic potential in determining the retention factors of benzimidazoles under study was analyzed.

  7. The capture and stabilization of curcumin using hydrophobically modified polyacrylate aggregates and hydrogels.

    PubMed

    Harada, Takaaki; Pham, Duc-Truc; Lincoln, Stephen F; Kee, Tak W

    2014-08-01

    Hydrophobically modified polyacrylates are shown to suppress the degradation of the medicinal pigment curcumin under physiological conditions. In aqueous solution, the 3% octadecyl randomly substituted polyacrylate, PAAC18, forms micelle-like aggregates at a concentration of <1 wt % and a hydrogel at >1 wt %. Under both conditions, PAAC18 shows a remarkable ability to suppress the degradation of curcumin at pH 7.4 and 37 °C such that its degradation half-life is increased by 1600-2000-fold. The suppression of degradation is attributed to hydrophobic interactions between curcumin and the octadecyl substituents of PAAC18 within the micelle-like aggregates and the hydrogel, as indicated by 2D NOESY (1)H NMR spectroscopy. UV-visible absorption titration results are consistent with the interaction of curcumin with five octadecyl substituents on average, which appears to substantially exclude water and greatly decrease the curcumin degradation rate. Dynamic light scattering and zeta potential measurements show the average hydrodynamic diameters of the PAAC18 aggregates to be 0.86-1.15 μm with a negative surface charge. In contrast to the octadecyl substitution, the 3% dodecyl randomly substituted polyacrylate, PAAC12, shows a negligible effect on slowing the degradation of curcumin, consistent with the dodecyl substituents being insufficiently long to capture curcumin in a adequately hydrophobic environment. These observations indicate the potential for PAAC18 to act as a model drug delivery system. PMID:25029529

  8. Sorption of benzotriazoles under the conditions of RP HPLC

    NASA Astrophysics Data System (ADS)

    Dzhabieva, S. A.; Kurbatova, S. V.; Belousova, Z. P.

    2016-02-01

    The results of a chromatographic study of sorption of several benzotriazole derivatives on octadecyl silica gel were reported. The physicochemical and electronic parameters of benzotriazoles were calculated. The effect of the structure of analyte molecules and eluent composition on chromatographic retention of these substances was analyzed.

  9. Physicochemical characteristics of the sorption of 4-aminoquinoline derivatives from water-acetonitrile solutions on nonpolar sorbents

    NASA Astrophysics Data System (ADS)

    Paramonova, A. S.; Kurbatova, S. B.; Zemtsova, M. N.

    2014-02-01

    Regularities of the retention of certain 4-aminoquinoline derivatives in the conditions of the reversed phase type of high performance liquid chromatography (HPLC) on octadecyl silica (ODS) and hypercrosslinked polystyrene (HCLPS) are studied. The correlation between the structure of aminoquinolines and their chromatographic retention is demonstrated.

  10. DOPC liposomes doped with octadecylferulate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Octadecyl ferulate, found in limit quantities in plants, is a natural phenolic derivative with the potential as a cosmeceautical, nutriceutical, and/or pharmaceutical ingredient because of its lipophilic and antioxidant properties. The current work demonstrates our ability to chemically synthesize a...

  11. OXIDATION OF PHENOLIC ANTIOXIDANTS IN A RIVER SYSTEM

    EPA Science Inventory

    The phenolic antioxidants are important commercial organic chemicals. Their environmental fate is of significance because of their abundance and usage patterns. This paper reports on the fates of 2,6-di-tert-butylphenol and the methyl and octadecyl esters of 3-(3,5-di-tert-butyl-...

  12. Structural and energetic characteristics of silicas modified by organosilicon compounds.

    PubMed

    Gun'ko, V M; Sheeran, D J; Augustine, S M; Blitz, J P

    2002-05-01

    Silica gels Davisil 633 and 643, and fumed silica Cab-O-Sil HS-5 with grafted 3-aminopropyl dimethylsilyl (APDMS), butyl dimethylsilyl (BDMS), octadecyl dimethylsilyl (ODDMS), and trimethylsilyl (TMS) groups of different concentrations were studied using the nitrogen adsorption method. Changes in the textural and energetic characteristics of modified silicas depend on features of the oxide matrices and grafted OSC. PMID:16290577

  13. Effects of nanoclay type on the physical and antimicrobial properties of PVOH-based nanocomposite films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyvinyl alcohols-based nanocomposite films were fabricated with four types of montmorillonite (MMT) nanoclay, including 18-amino stearic acid (I.24TL), methyl, bis hydroxyethyl, octadecyl ammonium (I.34TCN), di-methyl, di-hydrogenated tallow ammonium/siloxane (I.44PSS) organically modified MMT, an...

  14. 40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-methyl-, octadecyl ester, polymer with 1,1-dichloroethene, 2- methylamino]ethyl 2-propenoate, N...-propenoate and 2- amino]ethyl 2-propenoate 127133-66-8 2-Propenoic acid, 2-methyl-, polymers with Bu...-methyl, reaction products with 1,6-diisocyanatohexane homopolymer and ethylene glycol...

  15. Thermal characteristics of oleochemical carbonate binary mixtures for potential latent heat storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present study examines the thermal properties of melting and solidification for binary mixtures between dodecyl carbonate (1a), tetradecyl carbonate (1b), hexadecyl carbonate (1c), and octadecyl carbonate (1d) by differential scanning calorimetry (DSC) in order to gain further understanding of t...

  16. GdDOTAGA(C18)2: an efficient amphiphilic Gd(iii) chelate for the preparation of self-assembled high relaxivity MRI nanoprobes.

    PubMed

    Filippi, M; Remotti, D; Botta, M; Terreno, E; Tei, L

    2015-12-21

    A new amphiphilic GdDOTA-like complex functionalized with two octadecyl chains was synthesised and incorporated into the bilayer of liposomes and dendrimersomes. (1)H NMR relaxometric studies and in vivo MRI experiments on mice bearing a syngeneic melanoma tumour have shown a great improvement in performance. PMID:26468493

  17. Rifabutin-loaded solid lipid nanoparticles for inhaled antitubercular therapy: Physicochemical and in vitro studies.

    PubMed

    Gaspar, Diana P; Faria, Vasco; Gonçalves, Lídia M D; Taboada, Pablo; Remuñán-López, Carmen; Almeida, António J

    2016-01-30

    Systemic administration of antitubercular drugs can be complicated by off-target toxicity to cells and tissues that are not infected by Mycobacterium tuberculosis . Delivery of antitubercular drugs via nanoparticles directly to the infected cells has the potential to maximize efficacy and minimize toxicity. The present work demonstrates the potential of solid lipid nanoparticles (SLN) as a delivery platform for rifabutin (RFB). Two different RFB-containing SLN formulations were produced using glyceryl dibehenate or glyceryl tristearate as lipid components. Full characterization was performed in terms of particle size, encapsulation and loading efficiency, morphology by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) studies. Physical stability was evaluated when formulations were stored at 5 ± 3°C and in the freeze-dried form. Formulations were stable throughout lyophilization without significant variations on physicochemical properties and RFB losses. The SLN showed to be able to endure harsh temperature conditions as demonstrated by dynamic light scattering (DLS). Release studies revealed that RFB was almost completely released from SLN. In vitro studies with THP1 cells differentiated in macrophages showing a nanoparticle uptake of 46 ± 3% and 26 ± 9% for glyceryl dibehenate and glyceryl tristearate SLN, respectively. Cell viability studies using relevant lung cell lines (A549 and Calu-3) revealed low cytotoxicity for the SLN, suggesting these could be new potential vehicles for pulmonary delivery of antitubercular drugs. PMID:26656946

  18. 21 CFR 172.832 - Monoglyceride citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION... monooleate and its citric acid monoester manufactured by the reaction of glyceryl monooleate with citric acid... percent-17 percent. (b) It is used, or intended for use, in antioxidant formulations for addition to...

  19. 21 CFR 172.832 - Monoglyceride citrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.832... manufactured by the reaction of glyceryl monooleate with citric acid under controlled conditions may be safely... use, in antioxidant formulations for addition to oils and fats whereby the additive does not...

  20. 75 FR 20785 - Polyglyceryl Phthalate Ester of Coconut Oil Fatty Acids; Exemption from the Requirement of a...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-21

    ... . II. What Does this Correction Do? In the Federal Register of July 8, 2009, (74 FR 32456), EPA's... of polyglyceryl phthalate ester of coconut oil fatty acids, including fatty acid coco polymers with... acid coco of surfactants polymers with glyceryl and phthalic anhydride (CAS No. 67746-02-5) and...

  1. Investigations into the chemistry and insecticidal activity of euonymus europaeus seed oil and methanol extract

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Euonymus europaeus seeds and seed oil were investigated for their volatiles using GC-MS-FID, Headspace-SPME/GC-MS-FID, and derivative GC-MS-FID for their volatiles and HPLC-DAD-CAD/MS for their non-volatile compounds. The seeds contain about 30% of fatty oil, mainly glyceryl trioleate, small amounts...

  2. Antihistamine Effect of a Pure Bioactive Compound Isolated from Slug (Diplosolenodes occidentalis) Material

    PubMed Central

    Jacob, AS; Simon, OR; Wheatle, D; Ruddock, P; McCook, K

    2014-01-01

    ABSTRACT Objective: Folklore claims of the therapeutic effect of garden slug (Diplosolenodes occidentalis) extract used to relieve bronchoconstriction in asthmatic individuals were never validated scientifically. The aim of this study was to isolate the pure bioactive compound from slug extract causing this effect. Methods: The crude ground material was prepared in ethanol and after filtration, separation by flash column chromatography method was done. The structure was elucidated by data from hydrogen and carbon nuclear magnetic resonance (NMR) profiles. The bioactive compound was assessed for dose dependent response effects on guinea pig tracheal smooth muscle pre-contracted with histamine. Receptor specificity studies were done by using HTMT dimaleate (H1 agonist). The type of antagonism was also identified. Results: The pure component isolated from garden slug material was identified by spectral studies as glyceryl trilinolenate. It caused dose-dependent relaxation in guinea pig tracheal smooth muscle strips pre-contracted with histamine, it acted via H1 type receptors and showed non-competitive antagonism. Conclusion: Glyceryl trilinolenate produced dose-dependent relaxation in tracheal smooth muscle strips in the presence of the agonist histamine. Glyceryl trilinolenate displayed non-competitive antagonism at H1 receptors in the trachea. This agent was able to alleviate bronchoconstriction in individuals presenting with atopic asthma in rural agricultural areas in Jamaica (verbal communications). It is possible that glyceryl trilinolenate can be used therapeutically to produce tracheal smooth muscle relaxation in individuals presenting with atopic asthma. PMID:25781274

  3. 76 FR 21339 - Certain New Chemicals; Receipt and Status Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-15

    ...)-, reaction products with bu glycidyl ether* P-11-0043......... 10/26/10 01/23/11 Gelest, Inc. (S) Conversion... alkanediol and cyclic ether, alkanoate P-11-0054......... 11/03/10 01/31/11 Mane, USA (G) Perfumery (S) 2H...) A component (G) Glyceryl in ultraviolet polypropylene light/electron glycol ether beam...

  4. The pharmacology and therapeutic relevance of endocannabinoid derived cyclo-oxygenase (COX)-2 products.

    PubMed

    Woodward, D F; Carling, R W C; Cornell, C L; Fliri, H G; Martos, J L; Pettit, S N; Liang, Y; Wang, J W

    2008-10-01

    The discovery of anandamide and 2-arachidonyl glycerol (2-AG) as naturally occurring mammalian endocannabinoids has had important and wide-reaching therapeutic implications. This, to a large extent, ensues from the complexity of endocannabinoid biology. One facet of endocannabinoid biology now receiving increased attention is the cyclo-oxygenase-2 (COX-2) derived oxidation products. Anandamide and 2-AG are oxidized to a range of PG-ethanolamides and PG-glyceryl esters that closely approaches that of the prostaglandins (PGs) formed from arachidonic acid. The pharmacology of these electrochemically neutral PG-ethanolamides (prostamides) and PG-glyceryl esters appears to be unique. No meaningful interaction with natural or recombinant prostanoid receptors is apparent. Nevertheless, in certain cells and tissues, prostamides and PG-glyceryl esters exert potent effects. The recent discovery of selective antagonists for the putative prostamide receptor has been a major advance in further establishing prostamide pharmacology as an entity distinct from prostanoid receptors. Since discovery of the prototype prostamide antagonist (AGN 204396), rapid progress has been made. The latest prostamide antagonists (AGN 211334-6) are 100 times more potent than the prototype and are, therefore, sufficiently active to be used in living animal studies. These compounds will allow a full evaluation of the role of prostamides in health and disease. To date, the only therapeutic application for prostamides is in glaucoma. The prostamide analog, bimatoprost, being the most effective ocular hypotensive drug currently available. Interestingly, PGE(2)-glyceryl ester and its chemically stable analog PGE(2)-serinolamide also lower intraocular pressure in dogs. Nevertheless, the therapeutic future of PGE(2)-glyceryl ester is more likely to reside in inflammation. PMID:18700152

  5. Synthesis of Discrete Alkyl-Silica Hybrid Nanowires and Their Assembly into Nanostructured Superhydrophobic Membranes.

    PubMed

    Yi, Deliang; Xu, Chenglong; Tang, Ruidie; Zhang, Xuehua; Caruso, Frank; Wang, Yajun

    2016-07-11

    We report the synthesis of highly flexible and mechanically robust hybrid silica nanowires (NWs) which can be used as novel building blocks to construct superhydrophobic functional materials with three-dimensional macroporous networks. The hybrid silica NWs, with an average diameter of 80 nm and tunable length of up to 12 μm, are prepared by anisotropic deposition of the hydrolyzed tetraethylorthosilicate in water/n-pentanol emulsions. A mechanistic investigation reveals that the trimethoxy(octadecyl)silane introduced to the water-oil interface in the synthesis plays key roles in stabilizing the water droplets to sub-100 nm and also growing a layer of octadecyl groups on the NW surface. This work opens a solution-based route for the one-pot preparation of monodisperse, hydrophobic silica NWs and represents an important step toward the bottom-up construction of 3D superhydrophobic materials and macroporous membranes. PMID:27278242

  6. Efficacy of nitric oxide, with or without continuing antihypertensive treatment, for management of high blood pressure in acute stroke (ENOS): a partial-factorial randomised controlled trial

    PubMed Central

    2015-01-01

    Summary Background High blood pressure is associated with poor outcome after stroke. Whether blood pressure should be lowered early after stroke, and whether to continue or temporarily withdraw existing antihypertensive drugs, is not known. We assessed outcomes after stroke in patients given drugs to lower their blood pressure. Methods In our multicentre, partial-factorial trial, we randomly assigned patients admitted to hospital with an acute ischaemic or haemorrhagic stroke and raised systolic blood pressure (systolic 140–220 mm Hg) to 7 days of transdermal glyceryl trinitrate (5 mg per day), started within 48 h of stroke onset, or to no glyceryl trinitrate (control group). A subset of patients who were taking antihypertensive drugs before their stroke were also randomly assigned to continue or stop taking these drugs. The primary outcome was function, assessed with the modified Rankin Scale at 90 days by observers masked to treatment assignment. This study is registered, number ISRCTN99414122. Findings Between July 20, 2001, and Oct 14, 2013, we enrolled 4011 patients. Mean blood pressure was 167 (SD 19) mm Hg/90 (13) mm Hg at baseline (median 26 h [16–37] after stroke onset), and was significantly reduced on day 1 in 2000 patients allocated to glyceryl trinitrate compared with 2011 controls (difference −7·0 [95% CI −8·5 to −5·6] mm Hg/–3·5 [–4·4 to −2·6] mm Hg; both p<0·0001), and on day 7 in 1053 patients allocated to continue antihypertensive drugs compared with 1044 patients randomised to stop them (difference −9·5 [95% CI −11·8 to −7·2] mm Hg/–5·0 [–6·4 to −3·7] mm Hg; both p<0·0001). Functional outcome at day 90 did not differ in either treatment comparison—the adjusted common odds ratio (OR) for worse outcome with glyceryl trinitrate versus no glyceryl trinitrate was 1·01 (95% CI 0·91–1·13; p=0·83), and with continue versus stop antihypertensive drugs OR was 1·05 (0·90–1·22; p=0·55). Interpretation

  7. Optical absorption spectra and kinetics of transients of phenolic stabilizers in n-hexadecane; A pulse radiolysis study

    NASA Astrophysics Data System (ADS)

    Brede, O.

    By means of pulse radiolysis experiments the formation of transients derived from differently structured phenolic stabilizers such as 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and bis-(2-hydroxy-3-tert-butyl-5-methylphenyl)sulfide and one of its isomers in n-hexadecane solution was analyzed. Some phenoxyl and cyclohexadienyl type radicals, anions and their subsequent radical products are identified and characterized kinetically.

  8. Recurrent myocardial infarction secondary to Prinzmetal’s variant angina

    PubMed Central

    Murdoch, Dale; Dhillon, Priyanka; Niranjan, Selvanayagam

    2015-01-01

    Prinzmetal’s variant angina describes chest pain secondary to reversible coronary artery vasospasm in the context of both diseased and non-diseased coronary arteries. Symptoms typically occur when the patient is at rest and are associated with transient ST-segment elevation. Acute episodes respond to glyceryl trinitrate, but myocardial infarction and other potentially fatal complications can occur, and long-term management can be challenging. Although it is not well understood, the underlying mechanism appears to involve a combination of endothelial damage and vasoactive mediators. In this case, a 35-year-old woman with myocardial infarction secondary to coronary artery vasospasm experienced recurrent chest pain. Coronary angiography revealed severe focal stenosis in the mid left anterior descending artery, which completely resolved after administration of intracoronary glyceryl trinitrate. The patient was discharged on nitrates and calcium channel blockers. The patient re-presented with another myocardial infarction, requiring up-titration of medical therapy. PMID:26034323

  9. [Studies on the constituents of trichosanthes root. III. Constituents of roots of Trichosanthes bracteata Voigt].

    PubMed

    Kitajima, J; Mukai, A; Masuda, Y; Tanaka, Y

    1989-04-01

    From the fresh roots of Trichosanthes bracteata Voigt., the following substances were identified: methyl palmitate, palmitic acid, suberic acid, alpha-spinasterol, stigmast-7-en-3 beta-ol, alpha-spinasterol 3-O-beta-D-glucopyranoside, stigmast-7-en-3 beta-ol 3-O-beta-D-glucopyranoside, glyceryl 1-palmitate, glyceryl 1-stearate, bryonolic acid, cucurbitacin B, isocucurbitacin B, 3-epi-isocucurbitacin B, 23,24-dihydrocucurbitacin B, 23,24-dihydroisocucurbitacin B, 23,24-dihydro-3-epi-isocucurbitacin B, cucurbitacin D, isocucurbitacin D and D-glucose. This root contains more than 6 times cucurbitacin of the root of T. kirilowii Maxim. var. japonicum Kitam. PMID:2760813

  10. Statistical analysis plan for the 'Efficacy of Nitric Oxide in Stroke' (ENOS) trial.

    PubMed

    Bath, Philip M W; Houlton, Aimee; Woodhouse, Lisa; Sprigg, Nikola; Wardlaw, Joanna; Pocock, Stuart

    2014-04-01

    High blood pressure is common during the acute phase of stroke and is associated with a poor outcome. However, the management of high blood pressure remains unclear. The 'Efficacy of Nitric Oxide in Stroke' trial tested whether transdermal glyceryl trinitrate, a nitric oxide donor that lowers blood pressure, is safe and effective in improving outcome after acute stroke. Efficacy of Nitric Oxide in Stroke is an international multicenter, prospective, randomized, single-blind, blinded endpoint trial, with funding from the U.K. Medical Research Council. Patients with acute ischemic stroke or intracerebral hemorrhage and systolic blood pressure 140-220 mmHg were randomized to glyceryl trinitrate or no glyceryl trinitrate and, where relevant, to continue or stop prestroke antihypertensive therapy. The primary outcome is shift in modified Rankin Scale at three-months. Patients or relatives gave written informed (proxy) consent, and all sites had research ethics approval. Analyses will be done by intention to treat. This paper and attachment describe the trial's statistical analysis plan, developed prior to unblinding of date. The statistical analysis plan contains design and methods for analyses, and unpopulated tables and figures for the two primary publications and some secondary publications. The database will be locked in late February 2014 in preparation for presentation of the results in May 2014. The data from the trial will improve the precision of the estimates of the overall treatment effects (efficacy and safety) of results from completed trials of blood pressure management in acute stroke, and provide the first large-scale randomized evidence on transdermal glyceryl trinitrate, and of continuing (vs. stopping) prestroke antihypertensive medications, in acute stroke. PMID:24588789

  11. Electrochemical characterization of bilayer lipid membrane-semiconductor junctions

    SciTech Connect

    Zhao, Xiao Kang; Baral, S.; Fendler, J.H. )

    1990-03-08

    Three different systems of glyceryl monooleate (GMO), bilayer lipid membrane (BLM) supported semiconductor particles have been prepared and characterized. A single composition of particulate semiconductor deposited only on one side of the BLM constituted system A, two different compositions of particulate semiconductors sequentially deposited on the same side of the BLM represented system B, and two different compositions of particulate semiconductors deposited on the opposite sides of the BLM made up system C.

  12. Direct Synthesis of ESBO Derivatives-18O Labelled with Dioxirane

    PubMed Central

    Tommasi, Immacolata; Fusco, Caterina

    2013-01-01

    This work addresses a new approach developed in our laboratory, consisting in the application of isolated dimethyldioxirane (DDO, 1a) labelled with 18O for synthesis of epoxidized glyceryl linoleate (Gly-LLL, 2). We expect that this work could contribute in improving analytical methods for the determination of epoxidized soybean oil (ESBO) in complex food matrices by adopting an 18O-labelled-epoxidized triacylglycerol as an internal standard. PMID:24163617

  13. 21 CFR 184.1901 - Triacetin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Triacetin. 184.1901 Section 184.1901 Food and....1901 Triacetin. (a) Triacetin (C8 H14O6, CAS Reg. No. 102-76-1), also known as 1,2,3,-propanetriol triacetate or glyceryl triacetate, is the triester of glycerin and acetic acid. Triacetin can be prepared...

  14. Development of novel sustained release matrix pellets of betahistine dihydrochloride: effect of lipophilic surfactants and co-surfactants.

    PubMed

    Shamma, Rehab Nabil; Basalious, Emad B; Shoukri, Raguia

    2012-01-01

    Sustained release matrix pellets of the freely water soluble drug, betahistine dihydrochloride (BH), were prepared using freeze pelletization technique. Different waxes and lipids (cetyl alcohol, beeswax, glyceryl tripalmitate (GTP) and glyceryl tristearate) were evaluated for the preparation of matrix pellets. A D-optimal design was employed for the optimization and to explore the effect of drug loading (X(1)), concentration of lipophilic surfactant (X(2)), concentration of co-surfactant (X(3)) and wax type (X(4)) on the release extent of the drug from matrix pellets. The entrapment efficiency (Y(1)), pellet diameter (Y(2)), and the percentage drug released at given times were selected as dependent variables. Results revealed a significant impact of all independent variables on drug release from the formulated pellets. The lipophilic surfactant significantly increased both the entrapment efficiency and the in vitro drug release and significantly decreased the pellet size. The optimized BH-loaded pellets were composed of 19.95% drug loading, 9.95% Span(®) 80 (surfactant), 0.25% Capmul(®) (co-surfactant) using glyceryl tripalmitate as a matrix former. The release profiles of the drug from hard gelatin capsule containing optimized pellets equivalent to 32 mg BH was similar to that of target release model for once-daily administration based on similarity factor. It could be concluded that a promising once-daily capsule containing sustained release pellets of BH was successfully designed. PMID:21770719

  15. Acute Lipotoxicity Regulates Severity of Biliary Acute Pancreatitis without Affecting Its Initiation

    PubMed Central

    Durgampudi, Chandra; Noel, Pawan; Patel, Krutika; Cline, Rachel; Trivedi, Ram N.; DeLany, James P.; Yadav, Dhiraj; Papachristou, Georgios I.; Lee, Kenneth; Acharya, Chathur; Jaligama, Deepthi; Navina, Sarah; Murad, Faris; Singh, Vijay P.

    2015-01-01

    Obese patients have worse outcomes during acute pancreatitis (AP). Previous animal models of AP have found worse outcomes in obese rodents who may have a baseline proinflammatory state. Our aim was to study the role of acute lipolytic generation of fatty acids on local severity and systemic complications of AP. Human postpancreatitis necrotic collections were analyzed for unsaturated fatty acids (UFAs) and saturated fatty acids. A model of biliary AP was designed to replicate the human variables by intraductal injection of the triglyceride glyceryl trilinoleate alone or with the chemically distinct lipase inhibitors orlistat or cetilistat. Parameters of AP etiology and outcomes of local and systemic severity were measured. Patients with postpancreatitis necrotic collections were obese, and 13 of 15 had biliary AP. Postpancreatitis necrotic collections were enriched in UFAs. Intraductal glyceryl trilinoleate with or without the lipase inhibitors resulted in oil red O–positive areas, resembling intrapancreatic fat. Both lipase inhibitors reduced the glyceryl trilinoleate–induced increase in serum lipase, UFAs, pancreatic necrosis, serum inflammatory markers, systemic injury, and mortality but not serum alanine aminotransferase, bilirubin, or amylase. We conclude that UFAs are enriched in human necrotic collections and acute UFA generation via lipolysis worsens pancreatic necrosis, systemic inflammation, and injury associated with severe AP. Inhibition of lipolysis reduces UFA generation and improves these outcomes of AP without interfering with its induction. PMID:24854864

  16. Comparative studies of lamivudine-zidovudine nanoparticles for the selective uptake by macrophages.

    PubMed

    Sankar, V; Nareshkumar, Parmar Nilaykumar; Ajitkumar, Gohel Nishit; Penmetsa, Shalini Devi; Hariharan, Sivaram

    2012-09-01

    The present study investigates the specific drug targeting of anti retroviral drugs, such as lamivudine and zidovudine, after intraperitoneal (i.p) injection by incorporation into polymeric nanoparticles (PNs) and solid lipid nanoparticles (SLNs). Our results showed that Glyceryl Monosterate-Poloxamer 188 SLNs (average diameter of 522.466 nm) showed slow drug release rates (63.18% of lamivudine and 62.37% of zidovudine were released in 12 hrs) among all the SLN formulations. For Poly lactic-co-glycolic acid (PLGA)-Poloxamer 188 PNs (average diameter of 70.348 nm), there were faster release rates of both lamivudine and zidovudine (97% and 94.06%, respectively, in 12 hrs). Tissue distribution studies were carried out in mice and concentrations of drugs in different organs were determined using high performance liquid chromatography (HPLC) after i.p. administration. Glyceryl Monosterate-Poloxamer 188 SLNs and PLGA-Poloxamer 188 PNs showed increase in the distribution of lamivudine and zidovudine to liver and spleen when compared to the drugs in solution. Also, Glyceryl Monosterate-P 188 SLNs showed higher concentration of drugs in RES organs than PLGA-P 188 PNs. PMID:22452408

  17. Inhibition of Listeria monocytogenes by fatty acids and monoglycerides.

    PubMed Central

    Wang, L L; Johnson, E A

    1992-01-01

    Fatty acids and monoglycerides were evaluated in brain heart infusion broth and in milk for antimicrobial activity against the Scott A strain of Listeria monocytogenes. C12:0, C18:3, and glyceryl monolaurate (monolaurin) had the strongest activity in brain heart infusion broth and were bactericidal at 10 to 20 micrograms/ml, whereas potassium (K)-conjugated linoleic acids and C18:2 were bactericidal at 50 to 200 micrograms/ml. C14:0, C16:0, C18:0, C18:1, glyceryl monomyristate, and glyceryl monopalmitate were not inhibitory at 200 micrograms/ml. The bactericidal activity in brain heart infusion broth was higher at pH 5 than at pH 6. In whole milk and skim milk, K-conjugated linoleic acid was bacteriostatic and prolonged the lag phase especially at 4 degrees C. Monolaurin inactivated L. monocytogenes in skim milk at 4 degrees C, but was less inhibitory at 23 degrees C. Monolaurin did not inhibit L. monocytogenes in whole milk because of the higher fat content. Other fatty acids tested were not effective in whole or skim milk. Our results suggest that K-conjugated linoleic acids or monolaurin could be used as an inhibitory agent against L. monocytogenes in dairy foods. Images PMID:1610184

  18. Effects of dietary carbohydrate on hepatic de novo lipogenesis in European seabass (Dicentrarchus labrax L.).

    PubMed

    Viegas, Ivan; Jarak, Ivana; Rito, João; Carvalho, Rui A; Metón, Isidoro; Pardal, Miguel A; Baanante, Isabel V; Jones, John G

    2016-07-01

    Farmed seabass have higher adiposity than their wild counterparts and this is often attributed to carbohydrate (CHO) feeding. Whether this reflects a reduction in fat oxidation, increased de novo lipogenesis (DNL), or both, is not known. To study the effects of high CHO diets on hepatic TG biosynthesis, hepatic TG deuterium ((2)H) enrichment was determined following 6 days in (2)H-enriched tank water for fish fed with a no-CHO control diet (CTRL), and diets with digestible starch (DS) and raw starch (RS). Hepatic fractional synthetic rates (FSRs, percent per day(-1)) were calculated for hepatic TG-glyceryl and FA moieties through (2)H NMR analysis. Glyceryl FSRs exceeded FA FSRs in all cases, indicating active cycling. DS fish did not show increased lipogenic potential compared to CTRL. RS fish had lower glyceryl FSRs compared with the other diets and negligible levels of FA FSRs despite similar hepatic TG levels to CTRL. DS-fed fish showed higher activity for enzymes that can provide NADPH for lipogenesis, relative to CTRL in the case of glucose-6-phosphate dehydrogenase (G6PDH) and relative to RS for both G6PDH and 6-phosphogluconate dehydrogenase. This approach indicated that elevated hepatic adiposity from DS feeding was not attributable to increased DNL. PMID:27247346

  19. Thermoreversible Gels Composed of Colloidal Silica Rods with Short-Range Attractions.

    PubMed

    Murphy, Ryan P; Hong, Kunlun; Wagner, Norman J

    2016-08-23

    Dynamic arrest transitions of colloidal suspensions containing nonspherical particles are of interest for the design and processing of various particle technologies. To better understand the effects of particle shape anisotropy and attraction strength on gel and glass formation, we present a colloidal model system of octadecyl-coated silica rods, termed as adhesive hard rods (AHR), which enables control of rod aspect ratio and temperature-dependent interactions. The aspect ratios of silica rods were controlled by varying the initial TEOS concentration following the work of Kuijk et al. (J. Am. Chem. Soc., 2011, 133, 2346-2349) and temperature-dependent attractions were introduced by coating the calcined silica rods with an octadecyl-brush and suspending in tetradecane. The rod length and aspect ratio were found to increase with TEOS concentration as expected, while other properties such as the rod diameter, coating coverage, density, and surface roughness were nearly independent of the aspect ratio. Ultrasmall angle X-ray scattering measurements revealed temperature-dependent attractions between octadecyl-coated silica rods in tetradecane, as characterized by a low-q upturn in the scattered intensity upon thermal quenching. Lastly, the rheology of a concentrated AHR suspension in tetradecane demonstrated thermoreversible gelation behavior, displaying a nearly 5 orders of magnitude change in the dynamic moduli as the temperature was cycled between 15 and 40 °C. The adhesive hard rod model system serves as a tunable platform to explore the combined influence of particle shape anisotropy and attraction strength on the dynamic arrest transitions in colloidal suspensions with thermoreversible, short-range attractions. PMID:27466883

  20. [Determination of saponosides from Panax ginseng C.A. Meyer. Comparison of official methods and HPLC].

    PubMed

    Guédon, D; Abbe, P; Cappelaere, N; Rames, N

    1989-01-01

    Official methods for determination of ginsenosides of the French and Helvetic Pharmacopoeias have been compared with HPLC method. Sample preparation schemes used are those of monographs with conventional solvent extraction and solid phase extraction with a polar and a non-polar sorbents, respectively kieselguhr and C 18 octadecyl. Liquid-solid sample clean-up with C 18 cartridge is the most effective procedure. Prior HPLC method, an hydrolysis step of malonylginsenosides is necessary. Very selective extraction resulting in highly purified solution authorizes reliable and rapid colorimetric determination from ginseng saponosides. PMID:2634933

  1. Alkylated phenol series in lacustrine black shales from the Nördlinger Ries, southern Germany.

    PubMed

    Barakat, Assem O; Baumgart, Susan; Brocks, Peter; Scholz-Böttcher, Barbara M; Rullkötter, Jürgen

    2012-08-01

    Several series of alkylated phenols were detected for the first time in the extractable bitumens of organic matter-rich sediments from the Nördlinger Ries (southern Germany). Most abundant and significant constituents comprise those with n-octadecyl, n-eicosanyl, phytanyl, and iso-pentadecyl and anteiso-pentadecyl substituents. The structures of these compounds are suggested from mass spectrometric and retention time data and coinjection with synthetic standards. Diagenetic alteration of phenolic algal lipids is suggested as a possible way to the formation of these compounds in the Nördlinger Ries sediments. PMID:22899507

  2. Determination of MDMA, MDEA and MDA in urine by high performance liquid chromatography with fluorescence detection.

    PubMed

    da Costa, José Luiz; da Matta Chasin, Alice Aparecida

    2004-11-01

    This paper describes the development and validation of analytical methodology for the determination of the use of MDMA, MDEA and MDA in urine. After a simple liquid extraction, the analyses were carried out on a high performance liquid chromatography (HPLC) in an octadecyl column, with fluorescence detection. The mobile phase using a sodium dodecyl sulfate ion-pairing reagent allows good separation and efficiency. The method showed good linearity and precision. Recovery was between 85 and 102% and detection limits were 10, 15 and 20 ng/ml for MDA, MDMA and MDEA, respectively. No interfering substances were detected with fluorescence detection. PMID:15458720

  3. Synthesis, structure, and excimer formation of vesicular assemblies carrying 1- or 2-naphthyl chromophores

    SciTech Connect

    Sisido, Masahiki; Sato, Yasuhiko; Sasaki, Hiroki; Imanishi, Yukio )

    1990-01-01

    New chromophoric amphiphiles consisting of optically active 1- or 2-naphthylalanines, each carrying two long alkyl chains and an ammonium ion, were synthesized. These amphiphiles were found to form vesicular structures in aqueous dispersion, and those having two octadecyl chains showed a gel-liquid crystalline transition around room temperature. UV and CD spectra showed exciton-type interactions for the 2-naphthyl amphiphiles in a high-energy excited state but no dimers or higher aggregates of the naphthyl groups in the ground state. Fluorescence spectra showed monomer and excimer emissions. The circularly polarized fluorescence spectra showed a positive signal at the excimer emission, indicating a chiral excimer configuration.

  4. Determination of amphetamine by HPLC after acetylation.

    PubMed

    Veress, T

    2000-01-01

    An analytical procedure has been developed for the HPLC determination of amphetamine by off-line pre-column derivatization. The proposed procedure consists of sample preparation by acetylation of amphetamine with acetic anhydride and a subsequent reversed-phase HPLC separation on an octadecyl silica stationary phase with salt-free mobile phase (tetrahydrofuran, acetonitrile, 0.1% triethylamine in water, 15:15:70 v/v) applying UV-detection. The applicability of the elaborated procedure is demonstrated with results obtained by analysis of real samples seized in the Hungarian black market. PMID:10641931

  5. Comparison of solvent extraction and solid-phase extraction for the determination of polychlorinated biphenyls in transformer oil.

    PubMed

    Mahindrakar, A N; Chandra, S; Shinde, L P

    2014-01-01

    Solid-phase extraction (SPE) of nine polychlorinated biphenyls (PCBs) from transformer oil samples was evaluated using octadecyl (CI8)-bonded porous silica. The efficiency of SPE of these PCBs was compared with those obtained by solvent extraction with DMSO and hexane. Average recoveries exceeding 95% for these PCBs were obtained via the SPE method using small cartridges containing 100mg of 40 pm CI8-bonded porous silica. The average recovery by solvent extraction with DMSO and hexane exceeded 83%. It was concluded that the recoveries and precision for the solvent extraction of PCBs were poorer than those for the SPE. PMID:24083901

  6. Functional double-shelled silicon nanocrystals for two-photon fluorescence cell imaging: spectral evolution and tuning

    NASA Astrophysics Data System (ADS)

    Chandra, Sourov; Ghosh, Batu; Beaune, Grégory; Nagarajan, Usharani; Yasui, Takao; Nakamura, Jin; Tsuruoka, Tohru; Baba, Yoshinobu; Shirahata, Naoto; Winnik, Françoise M.

    2016-04-01

    Functional near-IR (NIR) emitting nanoparticles (NPs) adapted for two-photon excitation fluorescence cell imaging were obtained starting from octadecyl-terminated silicon nanocrystals (ncSi-OD) of narrow photoluminescence (PL) spectra having no long emission tails, continuously tunable over the 700-1000 nm window, PL quantum yields exceeding 30%, and PL lifetimes of 300 μs or longer. These NPs, consisting of a Pluronic F127 shell and a core made up of assembled ncSi-OD kept apart by an octadecyl (OD) layer, were readily internalized into the cytosol, but not the nucleus, of NIH3T3 cells and were non-toxic. Asymmetrical field-flow fractionation (AF4) analysis was carried out to determine the size of the NPs in water. HiLyte Fluor 750 amine was linked via an amide link to NPs prepared with Pluronic-F127-COOH, as a first demonstration of functional NIR-emitting water dispersible ncSi-based nanoparticles.Functional near-IR (NIR) emitting nanoparticles (NPs) adapted for two-photon excitation fluorescence cell imaging were obtained starting from octadecyl-terminated silicon nanocrystals (ncSi-OD) of narrow photoluminescence (PL) spectra having no long emission tails, continuously tunable over the 700-1000 nm window, PL quantum yields exceeding 30%, and PL lifetimes of 300 μs or longer. These NPs, consisting of a Pluronic F127 shell and a core made up of assembled ncSi-OD kept apart by an octadecyl (OD) layer, were readily internalized into the cytosol, but not the nucleus, of NIH3T3 cells and were non-toxic. Asymmetrical field-flow fractionation (AF4) analysis was carried out to determine the size of the NPs in water. HiLyte Fluor 750 amine was linked via an amide link to NPs prepared with Pluronic-F127-COOH, as a first demonstration of functional NIR-emitting water dispersible ncSi-based nanoparticles. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01437b

  7. Analysis of micro-encapsulated d-limonene dimercaptan, a possible herbicide marker for Cannabis sprayed with paraquat, using gas chromatography.

    PubMed

    Turner, C E; Ma, C Y; Russell, M H; Elsohly, M A

    1981-01-01

    A method for the determination of encapsulated d-limonene dimercaptan (d-LDM), a possible marker for Cannabis sativa L. sprayed with herbicide, has been developed. The methodology includes a single-step extraction, followed by gas chromatography with flame photometric detector (FDP) using n-octadecyl mercaptan (n-octadecylthiol) as an internal standard. A liner relationship was obtained from spiked samples with an average coefficient of variation of 9.0 per cent. The method has been used to determine part-per-million levels of LDM in actual field experiments in Mexico. The FDP limit was found to be 7 ng for d-LDM. PMID:6913415

  8. Use of inorganic salts during the etching process in the fabrication of chemically modified capillaries for open tubular electrochromatography.

    PubMed

    Pesek, Joseph J; Matyska, Maria T; Velpula, Sunandini

    2005-05-01

    Capillaries for use in electrophoretic analyses are etched with ammonium bifluoride and in some cases a second inorganic salt is included in the process. The effects of the presence of these inorganic components in the surface matrix on the electromigration of heterocyclic aromatic amines and enkephalins are evaluated. Resolution, efficiency, and peak shape are used to compare the various columns. In one instance, the etched surface is then modified by the addition of an octadecyl moiety using a silanization/hydrosilation procedure. The surface properties of the various etched capillaries are also compared by electroosmotic flow measurements. PMID:15938182

  9. Anti-glioma activity and the mechanism of cellular uptake of asiatic acid-loaded solid lipid nanoparticles.

    PubMed

    Garanti, Tanem; Stasik, Aneta; Burrow, Andrea Julie; Alhnan, Mohamed A; Wan, Ka-Wai

    2016-03-16

    Asiatic acid (AA), a pentacyclic triterpene found in Centella Asiatica, has shown neuroprotective and anti-cancer activity against glioma. However, owing to its poor aqueous solubility, effective delivery and absorption across biological barriers, in particular the blood brain barrier (BBB), are challenging. Solid lipid nanoparticles (SLNs) have shown a promising potential as a drug delivery system to carry lipophilic drugs across the BBB, a major obstacle in brain cancer therapy. Nevertheless, limited information is available about the cytotoxic mechanisms of nano-lipidic carriers with AA on normal and glioma cells. This study assessed the anti-cancer efficacy of AA-loaded SLNs against glioblastoma and their cellular uptake mechanism in comparison with SVG P12 (human foetal glial) cells. SLNs were systematically investigated for three different solid lipids; glyceryl monostearate (MS), glyceryl distearate (DS) and glyceryl tristearate (TS). The non-drug containing MS-SLNs (E-MS-SLNs) did not show any apparent toxicity towards normal SVG P12 cells, whilst the AA-loaded MS-SLNs (AA-MS-SLNs) displayed a more favourable drug release profile and higher cytotoxicity towards U87 MG cells. Therefore, MS-SLNs were chosen for further in vitro studies. Cytotoxicity studies of SLNs (± AA) were performed using MTT assay where AA-SLNs showed significantly higher cytotoxicity towards U87 MG cells than SVG P12 normal cells, as confirmed by flow cell cytometry. Cellular uptake of SLNs also appeared to be preferentially facilitated by energy-dependent endocytosis as evidenced by fluorescence imaging and flow cell cytometry. Using the Annexin V-PI double staining technique, it was found that these AA-MS-SLNs displayed concentration-dependent apoptotic activity on glioma cells, which further confirms the potential of exploiting these AA-loaded MS-SLNs for brain cancer therapy. PMID:26775062

  10. Endocannabinoids and their oxygenation by cyclo-oxygenases, lipoxygenases and other oxygenases.

    PubMed

    Urquhart, P; Nicolaou, A; Woodward, D F

    2015-04-01

    The naturally occurring mammalian endocannabinoids possess biological attributes that extend beyond interaction with cannabinoid receptors. These extended biological properties are the result of oxidative metabolism of the principal mammalian endocannabinoids arachidonoyl ethanolamide (anandamide; A-EA) and 2-arachidonoylglycerol (2-AG). Both endocannabinoids are oxidized by cyclo-oxygenase-2 (COX-2), but not by COX-1, to a series of prostaglandin derivatives (PGs) with quite different biological properties from those of the parent substrates. PG ethanolamides (prostamides, PG-EAs) and PG glyceryl esters (PG-Gs) are not only pharmacologically distinct from their parent endocannabinoids, they are distinct from the corresponding acidic PGs, and are differentiated from each other. Ethanolamides and glyceryl esters of the major prostanoids PGD2, PGE2, PGF2α, and PGI2 are formed by the various PG synthases, and thromboxane ethanolamides and glyceryl esters are not similarly produced. COX-2 is also of interest by virtue of its corollary central role in modulating endocannabinoid tone, providing a new therapeutic approach for treating pain and anxiety. Other major oxidative conversion pathways are provided for both A-EA and 2-AG by several lipoxygenases (LOXs), resulting in the formation of numerous hydroxyl metabolites. These do not necessarily represent inactivation pathways for endocannabinoids but may mimic or modulate the endocannabinoids or even display alternative pharmacology. Similarly, A-EA and 2-AG may be oxidized by P450 enzymes. Again a very diverse number of metabolites are formed, with either cannabinoid-like biological properties or an introduction of disparate pharmacology. The biological activity of epoxy and hydroxyl derivatives of the endocannabinoids remains to be fully elucidated. This review attempts to consolidate and compare the findings obtained to date in an increasingly important research area. This article is part of a Special Issue entitled

  11. The fusion of erythrocytes by fatty acids, esters, retinol and alpha-tocopherol.

    PubMed

    Ahkong, Q F; Fisher, D; Tampion, W; Lucy, J A

    1973-09-01

    1. The ability of a number of carboxylic acids, their esters, retinol and alpha-tocopherol to induce fusion of hen erythrocytes in vitro was investigated. 2. Some 30 different fat-soluble substances (100mug/ml) were found to cause the formation of multinucleated erythrocytes with a suspension of 3x10(8) erythrocytes/ml. The most effective agents induced fusion within 5-10min at 37 degrees C; some substances required about 1h. 3. Inclusion of Dextran 60C in the test medium minimized colloid osmotic lysis caused by exogenous lipids that induce cell fusion. 4. Cell swelling, followed by cell adhesion, was then seen to precede cell fusion. 5. Fusion occurred with C(10)-C(14) saturated carboxylic acids, with unsaturated, longer-chain carboxylic acids and their mono-esters; retinol, and to a lesser extent alpha-tocopherol, also caused cell fusion. 6. C(6)-C(9), C(15), C(16) and C(18) saturated carboxylic acids did not induce fusion within 4h; glyceryl dioleate was only weakly active, and glyceryl trioleate was inactive in the test system. 7. Fusion was facilitated by a high ratio of chemical agents to cell number and by incubation between pH5 and 6. It was inhibited by EDTA and by serum albumin. 8. Glyceryl mono-oleate caused both a similar fusion of several species of mammalian erythrocyte and the interspecific fusion of human and chicken erythrocytes. 9. The term ;fusogenic' is proposed to describe chemical, viral and physical agents that cause membranes to fuse. 10. The biochemical mechanisms involved and the possible biological significance of membrane fusion by fusogenic lipids are discussed. PMID:4204034

  12. Short-Chain Flavor Ester Synthesis in Organic Media by an E. coli Whole-Cell Biocatalyst Expressing a Newly Characterized Heterologous Lipase

    PubMed Central

    Brault, Guillaume; Shareck, François; Hurtubise, Yves; Lépine, François; Doucet, Nicolas

    2014-01-01

    Short-chain aliphatic esters are small volatile molecules that produce fruity and pleasant aromas and flavors. Most of these esters are artificially produced or extracted from natural sources at high cost. It is, however, possible to ‘naturally’ produce these molecules using biocatalysts such as lipases and esterases. A gene coding for a newly uncovered lipase was isolated from a previous metagenomic study and cloned into E. coli BL21 (DE3) for overexpression using the pET16b plasmid. Using this recombinant strain as a whole-cell biocatalyst, short chain esters were efficiently synthesized by transesterification and esterification reactions in organic media. The recombinant lipase (LipIAF5-2) showed good affinity toward glyceryl trioctanoate and the highest conversion yields were obtained for the transesterification of glyceryl triacetate with methanol. Using a simple cetyl-trimethylammonium bromide pretreatment increased the synthetic activity by a six-fold factor and the whole-cell biocatalyst showed the highest activity at 40°C with a relatively high water content of 10% (w/w). The whole-cell biocatalyst showed excellent tolerance to alcohol and short-chain fatty acid denaturation. Substrate affinity was equally effective with all primary alcohols tested as acyl acceptors, with a slight preference for methanol. The best transesterification conversion of 50 mmol glyceryl triacetate into isoamyl acetate (banana fragrance) provided near 100% yield after 24 hours using 10% biocatalyst loading (w/w) in a fluidized bed reactor, allowing recycling of the biocatalyst up to five times. These results show promising potential for an industrial approach aimed at the biosynthesis of short-chain esters, namely for natural flavor and fragrance production in micro-aqueous media. PMID:24670408

  13. High-resolution proton nuclear magnetic resonance characterization of seminolipid from bovine spermatozoa.

    PubMed

    Alvarez, J G; Storey, B T; Hemling, M L; Grob, R L

    1990-06-01

    The high-resolution one- and two-dimensional proton nuclear magnetic resonance (1H-NMR) characterization of seminolipid from bovine spermatozoa is presented. The 1H-NMR data was confirmed by gas-liquid chromatography-mass spectrometric analysis of the partially methylated alditol acetates of the sugar unit, mild alkaline methanolysis of the glyceryl ester, mobility on normal phase and diphasic thin-layer chromatography (HPTLC), and fast atom bombardment mass spectrometry (FAB-MS). The structure of the molecule corresponds to 1-O-hexadecyl-2-O-hexadecanoyl-3-O-beta-D-(3'-sulfo)-galactopyranosyl- sn-glycerol. PMID:2373957

  14. Concise synthesis of ether analogues of lysobisphosphatidic acid.

    PubMed

    Jiang, Guowei; Xu, Yong; Falguières, Thomas; Gruenberg, Jean; Prestwich, Glenn D

    2005-09-01

    We describe a versatile, efficient method for the preparation of ether analogues of (S,S)-lysobisphosphatidic acid (LBPA) and its enantiomer from (S)-solketal. Phosphorylation of a protected sn-2-O-octadecenyl glyceryl ether with 2-cyanoethyl bis-N,N-diisopropylamino phosphine and subsequent deprotection generated the bisether LBPA analogues. By simply changing the sequence of deprotection steps, we obtained the (R,R)- and (S,S)-enantiomers of 2,2'-bisether LBPA. An ELISA assay with anti-LBPA monoclonal antibodies showed that the bisether LBPAs were recognized with the same affinity as the natural 2,2'-bisoleolyl LBPA. [reaction: see text] PMID:16119911

  15. Holographic interferometry of ultrasmall-pressure-induced curvature changes of bilayer lipid membranes

    SciTech Connect

    Picard, G.; Schneider-Henriquez, J.E.; Fendler, J.H. )

    1990-01-25

    Two-exposure interferometric holograms have been shown to sensitively report ultrasmall-pressure (10 natm)-induced curvature changes in glyceryl monooleate (GMO) bilayer lipid membranes (BLMs). The number of concentric fringes observed, and hence the lateral distance between the plane of the Teflon and the BLM, increased linearly with increasing transmembrane pressure and led to a value of 1.1 {plus minus} 0.05 dyn/cm for the surface tension of the BLM. BLMs with appreciable Plateau-Gibbs borders have been shown to undergo nonuniform deformation; the bilayer portion is distorted less than the surrounding Plateau-Gibbs border upon the application of a transmembrane pressure gradient.

  16. Lipid nanoparticles for oral delivery of raloxifene: optimization, stability, in vivo evaluation and uptake mechanism.

    PubMed

    Ravi, Punna Rao; Aditya, N; Kathuria, Himanshu; Malekar, Srinivas; Vats, Rahul

    2014-05-01

    Raloxifene HCl (RLX) shows low oral bioavailability (<2%) in humans due to poor aqueous solubility and extensive (>90%) metabolism in gut. Lipid nanoparticles (SLN) with glyceryl tribehenate were designed to enhance drug's oral bioavailability. Box-Bhenken design was used to optimize manufacturing conditions. Optimized SLN had particle size of 167±3nm and high encapsulation efficiency (>92%). Oral bioavailability of RLX from SLN was improved by 3.24 folds compared to free RLX in female Wistar rats. Both clathrin and caveolae mediated endocytosis pathways were involved in the uptake of SLN. Lymphatic transport inhibitor, cycloheximide significantly reduced oral bioavailability of SLN. PMID:24378615

  17. Nanostructured lipid carriers as a potential vehicle for Carvedilol delivery: Application of factorial design approach.

    PubMed

    Patil, Ganesh B; Patil, Nandkishor D; Deshmukh, Prashant K; Patil, Pravin O; Bari, Sanjay B

    2016-01-01

    Present invention relates to design of nanostructured lipid carriers (NLC) to augment oral bioavailability of Carvedilol (CAR). In this attempt, formulations of CAR-NLCs were prepared with glyceryl-monostearate (GMS) as a lipid, poloxamer 188 as a surfactant and tween 80 as a co-surfactant using high pressure homogenizer by 2(3) factorial design approach. Formed CAR-NLCs were assessed for various performance parameters. Accelerated stability studies demonstrated negligible change in particle size and entrapment efficiency, after storage at specified time up to 3 months. The promising findings in this investigation suggest the practicability of these systems for enhancement of bioavailability of drugs like CAR. PMID:24866725

  18. Boundary lubrication of stainless steel and CoCrMo alloy based on phosphorous and boron compounds in oil-in-water emulsion

    NASA Astrophysics Data System (ADS)

    Yan, Jincan; Zeng, Xiangqiong; Ren, Tianhui; van der Heide, Emile

    2014-10-01

    Emulsion lubrication is widely used in metal forming operations and has potential applications in the biomedical field, yet the emulsion lubrication mechanism is not well understood. This work explores the possibilities of three different oil-in-water (O/W) emulsions containing dibutyl octadecylphosphoramidate (DBOP), 6-octadecyl-1,3,6,2-dioxazaborocan-2-ol calcium salt (ODOC) and 2-(4-dodecylphenoxy)-6-octadecyl-1,3,6,2-dioxazaborocane (DOB) to generate boundary films on stainless steel AISI 316 and CoCrMo alloy surfaces. Experimental results show lower friction values for the emulsions in combination with CoCrMo compared to AISI 316. The different performance of the additives is related to the composition of the adsorption and reaction film on the interacting surfaces, which was shown to be dependent on the active elements and molecular structure of the additives. The friction profile of the emulsions indicates that the emulsion appears to be broken during the rubbing process, then the additives adsorb onto the metal surface to form protecting boundary layers. The XPS analysis shows that for boundary lubrication conditions, the additive molecules in the emulsion first adsorb on the metal surface after the droplet is broken, and then decompose and react with the metal surface during the rubbing process to form stable lubricating films on the rubbed surfaces.

  19. Porous silica particles grafted with an amphiphilic side-chain polymer as a stationary phase in reversed-phase high-performance liquid chromatography.

    PubMed

    Shahruzzaman, Md; Takafuji, Makoto; Ihara, Hirotaka

    2015-07-01

    The amphiphilic polymer-grafted silica was newly prepared as a stationary phase in high-performance liquid chromatography. Poly(4-vinylpyridine) with a trimethoxysilyl group at one end was grafted onto porous silica particles and the pyridyl side chains were quaternized with 1-bromooctadecane. The obtained poly(octadecylpyridinium)-grafted silica was characterized by elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy and Brunauer-Emmett-Teller analysis. The degree of quaternization of the pyridyl groups on the obtained stationary phase was estimated to be 70%. The selective retention behaviors of polycyclic aromatic hydrocarbons including some positional isomers were investigated using poly(octadecylpyridinium)-grafted silica as an amphiphilic polymer stationary phase in high-performance liquid chromatography and results were compared with commercially available polymeric octadecylated silica and phenyl-bonded silica columns. The results indicate that the selectivity toward polycyclic aromatic hydrocarbons exhibited by the amphiphilic polymer stationary phase is higher than the corresponding selectivity exhibited by a conventional phenyl-bonded silica column. However, compared with the polymeric octadecylated silica phase, the new stationary phase presents similar retention behavior for polycyclic aromatic hydrocarbons but different retention behavior particularly for positional isomers of disubstituted benzenes as the aggregation structure of amphiphilic polymers on the surface of silica substrate has been altered during mobile phase variation. PMID:25944152

  20. High-performance liquid chromatographic determination of benzoylurea insecticides residues in grapes and wine using liquid and solid-phase extraction.

    PubMed

    Miliadis, G E; Tsiropoulos, N G; Aplada-Sarlis, P G

    1999-03-12

    A method for the determination of the benzoylurea insecticides diflubenzuron, triflumuron, teflubenzuron, lufenuron and flufenoxuron in grapes and wine by HPLC has been developed and validated. Grape samples (50 g) were homogenized and extracted with ethyl acetate-sodium sulfate and further cleaned-up by solid-phase extraction on silica sorbent. Wine samples (10 ml) diluted with water (1:3) were solid-phase extracted on an octadecyl sorbent using methanol as the eluent. The pesticides were separated on a reversed-phase octadecyl narrow-bore column by gradient elution and the residues were determined with a UV diode array detector. The calibration plots were linear over the range 0.05-5 micrograms/ml. Recoveries of benzoylurea pesticides from spiked grapes (0.02-2.0 mg/kg) and wine (0.01-0.2 mg/l) were 85.8-101.6% and 69.1-104.8%, respectively, and the limits of quantification for these insecticides were < 0.01 mg/kg for grapes and < 0.01 mg/l for wine. The method was applied to the determination of flufenoxuron and teflubenzuron residues in grapes from treated fields and in produced wine. PMID:10220916

  1. Aging and nonlinear rheology of thermoreversible colloidal gels

    NASA Astrophysics Data System (ADS)

    Wagner, Norman; Gordon, Melissa; Kloxin, Christopher

    Colloidal dispersions are found in a wide variety of consumer products such as paint, food and pharmaceuticals. We investigate gel formation and aging in a thermoreverible gel consisting of octadecyl-coated silica nanoparticles suspended in n-tetradecane. In this system, the octadecyl brush can undergo a phase change allowing the attractions between particles to be tuned by temperature (1,2). By probing the system with steady shear and large amplitude oscillatory shear, we have studied the effect of thermal history and shear history on gel formation and gel mechanical properties during aging. Gels were formed by approaching a common temperature from above and below to determine a reference state from which creep tests were conducted. Creep ringing was observed as expected for the viscoelastic gel. The rheological aging is interpreted in terms of the gel microstructure formed with differing thermal and shear histories to determine how processing affects structure. Recently proposed scaling laws for the rheology and structure under flow are explored within the context of gel aging (3). Through rheological and microstructural measurements, we will further the understanding of gel formation and aging in this model system which may be applied to processing conditions in an industrial setting.

  2. Bonded-phase extraction column isolation of organic compounds in groundwater at a hazardous waste site

    USGS Publications Warehouse

    Rostad, C.E.; Pereira, W.E.; Ratcliff, S.M.

    1984-01-01

    A procedure for isolation of hazardous organic compounds from water for gas chromatography/mass spectrometry analysis Is presented and applied to creosote- and pentachlorophenol-contaminated groundwater resulting from wood-treatment processes. This simple procedure involved passing a 50-100-mL sample through a bonded-phase extraction column, eluting the trapped organic compounds from the column with 2-4 mL of solvent, and evaporating the sample to 100 ??L with a stream of dry nitrogen, after which the sample was ready for gas chromatography/mass spectrometry analysis. Representative compounds indicative of creosote contamination were used for recovery and precision studies from the cyclohexyl-bonded phase. Recovery of these compounds from n-octyl-, n-octadecyl-, cyclohexyl-, and phenyl-bonded phases was compared. The bonded phase that exhibited the best recovery and least bias toward acidic or basic cmpounds was the n-octadecyl phase. Detailed compound Identification Is given for compounds Isolated from creosote- and pentachlorophenol-contaminated groundwater using the cyclohexyl-bonded phase.

  3. A continuous spectrophotometric assay that distinguishes between phospholipase A1 and A2 activities.

    PubMed

    El Alaoui, Meddy; Soulère, Laurent; Noiriel, Alexandre; Popowycz, Florence; Khatib, Abdallah; Queneau, Yves; Abousalham, Abdelkarim

    2016-08-01

    A new spectrophotometric assay was developed to measure, continuously and specifically, phospholipase A1 (PLA1) or phospholipase A2 (PLA2) activities using synthetic glycerophosphatidylcholines (PCs) containing α-eleostearic acid, either at the sn-1 position [1-α-eleostearoyl-2-octadecyl-rac-glycero-3-phosphocholine (EOPC)] or at the sn-2 position [1-octadecyl-2-α-eleostearoyl-rac-glycero-3-phosphocholine (OEPC)]. The substrates were coated onto the wells of microtiter plates. A nonhydrolyzable ether bond, with a non-UV-absorbing alkyl chain, was introduced at the other sn position to prevent acyl chain migration during lipolysis. Upon enzyme action, α-eleostearic acid is liberated and then solubilized into the micellar phase. The PLA1 or PLA2 activity was measured by the increase in absorbance at 272 nm due to the transition of α-eleostearic acid from the adsorbed to the soluble state. EOPC and OEPC differentiate, with excellent accuracy, between PLA1 and PLA2 activity. Lecitase(®), guinea pig pancreatic lipase-related protein 2 (known to be a PLA1 enzyme), bee venom PLA2, and porcine pancreatic PLA2 were all used to validate the assay. Compared with current assays used for continuously measuring PLA1 or PLA2 activities and/or their inhibitors, the development of this sensitive enzymatic method, using coated PC substrate analogs to natural lipids and based on the UV spectroscopic properties of α-eleostearic acid, is a significant improvement. PMID:27194811

  4. Functional double-shelled silicon nanocrystals for two-photon fluorescence cell imaging: spectral evolution and tuning.

    PubMed

    Chandra, Sourov; Ghosh, Batu; Beaune, Grégory; Nagarajan, Usharani; Yasui, Takao; Nakamura, Jin; Tsuruoka, Tohru; Baba, Yoshinobu; Shirahata, Naoto; Winnik, Françoise M

    2016-04-28

    Functional near-IR (NIR) emitting nanoparticles (NPs) adapted for two-photon excitation fluorescence cell imaging were obtained starting from octadecyl-terminated silicon nanocrystals (ncSi-OD) of narrow photoluminescence (PL) spectra having no long emission tails, continuously tunable over the 700-1000 nm window, PL quantum yields exceeding 30%, and PL lifetimes of 300 μs or longer. These NPs, consisting of a Pluronic F127 shell and a core made up of assembled ncSi-OD kept apart by an octadecyl (OD) layer, were readily internalized into the cytosol, but not the nucleus, of NIH3T3 cells and were non-toxic. Asymmetrical field-flow fractionation (AF4) analysis was carried out to determine the size of the NPs in water. HiLyte Fluor 750 amine was linked via an amide link to NPs prepared with Pluronic-F127-COOH, as a first demonstration of functional NIR-emitting water dispersible ncSi-based nanoparticles. PMID:27076260

  5. A continuous spectrophotometric assay that distinguishes between phospholipase A1 and A2 activities[S

    PubMed Central

    El Alaoui, Meddy; Soulère, Laurent; Noiriel, Alexandre; Popowycz, Florence; Khatib, Abdallah; Queneau, Yves; Abousalham, Abdelkarim

    2016-01-01

    A new spectrophotometric assay was developed to measure, continuously and specifically, phospholipase A1 (PLA1) or phospholipase A2 (PLA2) activities using synthetic glycerophosphatidylcholines (PCs) containing α-eleostearic acid, either at the sn-1 position [1-α-eleostearoyl-2-octadecyl-rac-glycero-3-phosphocholine (EOPC)] or at the sn-2 position [1-octadecyl-2-α-eleostearoyl-rac-glycero-3-phosphocholine (OEPC)]. The substrates were coated onto the wells of microtiter plates. A nonhydrolyzable ether bond, with a non-UV-absorbing alkyl chain, was introduced at the other sn position to prevent acyl chain migration during lipolysis. Upon enzyme action, α-eleostearic acid is liberated and then solubilized into the micellar phase. The PLA1 or PLA2 activity was measured by the increase in absorbance at 272 nm due to the transition of α-eleostearic acid from the adsorbed to the soluble state. EOPC and OEPC differentiate, with excellent accuracy, between PLA1 and PLA2 activity. Lecitase®, guinea pig pancreatic lipase-related protein 2 (known to be a PLA1 enzyme), bee venom PLA2, and porcine pancreatic PLA2 were all used to validate the assay. Compared with current assays used for continuously measuring PLA1 or PLA2 activities and/or their inhibitors, the development of this sensitive enzymatic method, using coated PC substrate analogs to natural lipids and based on the UV spectroscopic properties of α-eleostearic acid, is a significant improvement. PMID:27194811

  6. Optimal value of filling pressure in the right side of the heart in acute right ventricular infarction.

    PubMed Central

    Berisha, S; Kastrati, A; Goda, A; Popa, Y

    1990-01-01

    Haemodynamic monitoring was performed within the first 48 hours after the onset of symptoms in basal conditions, during volume loading, and during infusion of glyceryl trinitrate in 41 patients who fulfilled the diagnostic electrocardiographic and haemodynamic criteria of right ventricular infarction. In most patients an increase of mean right atrial pressure up to 10-14 mm Hg was followed by an increase in right ventricular stroke work index. But raising the mean right atrial pressure above 14 mm Hg was almost always accompanied by a reduction in right ventricular stroke work index. When the mean right atrial pressure was reduced by intravenous glyceryl trinitrate to less than 14 mm Hg the right ventricular stroke index increased. The same response was seen with cardiac and stroke index. The mean (SD) values of optimal right atrial and pulmonary capillary pressures were 11.7 (2.1) and 16.5 (2.7) mm Hg respectively. Thus cardiac and stroke index increased and the right ventricle reached its maximum stroke work index when the filling pressure was 10-14 mm Hg. These values may be regarded as the optimal level of right ventricular filling pressure in patients with right ventricular infarction. PMID:2107863

  7. Effect of two hydrophobic polymers on the release of gliclazide from their matrix tablets.

    PubMed

    Hussain, Talib; Saeed, Tariq; Mumtaz, Ahmad M; Javaid, Zeeshan; Abbas, Khizar; Awais, Azeema; Idrees, Hafiz Arfat

    2013-01-01

    Gliclazide is an oral hypoglycemic agent, indicated in non insulin dependent diabetes mellitus and in patients with diabetic retinopathy. It has good tolerability and is a short acting sulfonyl urea that requires large dose to maintain the blood glucose level. So development of a sustained release formulation of gliclazide (GLZ) is required for better patient compliance. This study was conducted to assess the effects of different drug polymer ratios on the release profile of gliclazide from the matrix. Oral matrix tablets of gliclazide were prepared by hot melt method, using pure and blended mixture of glyceryl monostearate (GMS) and stearic acid (SA) in different ratios. In vitro release pattern was studied for 8 h in phosphate buffer media (pH 7.4). Different kinetic models including zero order, first order, Higuchi and Peppas were applied to evaluate drug release behavior. Drug excipient compatibility was evaluated by scanning with DSC and FTIR. Higuchi model was found the most appropriate model for describing the release profile of GLZ and non-Fickian release was found predominant mechanism of drug release. The release of drug from the matrix was greatly controlled by GMS while SA appeared to facilitate the release of drug from matrix tablets. FTIR results showed no chemical interaction between drug and the polymers, and DSC results indicated amorphous state of GLZ and polymers without significant complex formation. The results indicate that matrix tablets of gliclazide using glyceryl monostearate and stearic acid showed marked sustained release properties. PMID:23923399

  8. Analysis of alcohols, as dimethylglycine esters, by electrospray ionization tandem mass spectrometry.

    PubMed

    Johnson, D W

    2001-03-01

    Dimethylglycine (DMG) esters are new derivatives for the rapid, sensitive and selective analysis of primary and secondary alcohols, in complex mixtures, by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Their development was inspired by the use of the complementary dimethylaminoethyl esters for the trace, rapid analysis of fatty acids. DMG esters are simply prepared by heating a dichloromethane solution of the imidazolide of dimethylglycine, containing triethylamine, and an alcohol. DMG esters of long-chain fatty alcohols, isoprenoidal alcohols and hydroxy-acids are analysed by electrospray ionization tandem mass spectrometry with a precursor ion of m/z 104 scan. Diols, glyceryl esters, glyceryl ethers and some sterols are analysed by a neutral loss of 103 Da scan. Trimethylglycine (TMG) ester iodides, prepared by alkylation of DMG esters with methyl iodide, are more sensitive derivatives for molecules containing secondary alcohol groups, such as cholesterol and gibberellic acid. They are analysed by a precursor ion of m/z 118 scan. DMG or TMG derivatives were shown to be at least comparable and sometimes an order of magnitude more sensitive than N-methylpyridyl ether derivatives for ESI-MS/MS analysis of the different classes of alcohols. Applications of these derivatives for the diagnosis of inherited disorders and the analysis of natural products are presented. PMID:11312519

  9. Enhancing vitamin E bioaccessibility: factors impacting solubilization and hydrolysis of α-tocopherol acetate encapsulated in emulsion-based delivery systems.

    PubMed

    Yang, Ying; Decker, Eric Andrew; Xiao, Hang; McClements, David Julian

    2015-01-01

    Oil-soluble vitamins are often encapsulated within emulsion-based delivery systems to facilitate their incorporation into aqueous-based products. We have examined the influence of carrier oil type and simulated small intestinal fluid (SSIF) composition on the bioaccessibility of emulsified vitamin E using a gastrointestinal model. Oil-in-water emulsions containing vitamin E acetate were prepared using bile salts as emulsifier, and either long chain triacylglycerols (glyceryl trioleate, LCT) or medium chain triacylglycerols (glyceryl trioctanoate, MCT) as carrier oils. The addition of calcium (CaCl₂) to the SSIF increased the extent of lipid digestion in LCT-emulsions, but had little impact in MCT-emulsions. The bioaccessibility of vitamin E increased in the presence of calcium and phospholipids (DOPC) in LCT-emulsions, but decreased in MCT-emulsions. The highest bioaccessibility (≈66%) was achieved for LCT-emulsions when the SSIF contained both calcium and phospholipids. The conversion of α-tocopherol acetate to α-tocopherol after in vitro digestion was considerably higher for LCT-emulsions when calcium ions were present in the SSIF, but was not strongly affected by SSIF composition for MCT-emulsions. In general, this research provides important information about the factors influencing the bioaccessibility of emulsified vitamin E, which could be used to design more effective emulsion-based delivery systems for increasing the oral bioavailability of this important bioactive component. PMID:25312787

  10. A simple strategy to monitor lipase activity using liquid crystal-based sensors.

    PubMed

    Hu, Qiong-Zheng; Jang, Chang-Hyun

    2012-09-15

    In this study, we developed a simple label-free technique for monitoring the enzymatic activity of lipase using liquid crystal (LC)-based sensors. The optical response of LCs changed from a bright to dark appearance when an aqueous solution of lipase was in contact with a nematic LC, 4-cyano-4'-pentylbiphenyl (5CB), that was doped with glyceryl trioleate, which is a glyceride that can be enzymatically hydrolyzed by lipase. Since the oleic acid released from the enzymatic reaction could spontaneously form a self-assembled monolayer at the aqueous/LC interface due to its amphiphilic property, the orientation of the LCs transited from a planar to homeotropic state, which induced a change in the optical response of the LCs. We did not observe a bright-to-dark shift in the optical appearance of LCs when pure 5CB was immersed into the lipase solution. Moreover, we further confirmed the specificity of the enzymatic reaction by transferring an aqueous buffer solution not containing an analyte, or with bovine serum albumin (BSA) or trypsin onto the interface of aqueous solutions and the glyceryl trioleate-doped 5CB, which did not produce any distinctive contrast in the optical appearance. These results suggest the feasibility of measuring the enzymatic activity of lipase using the LC-based sensing technique. Furthermore, our strategy could also be used for the preparation of a self-assembled monolayer of carboxylates at the aqueous/LC interface. PMID:22967518

  11. In vivo study of an instantly formed lipid-water cubic phase formulation for efficient topical delivery of aminolevulinic acid and methyl-aminolevulinate.

    PubMed

    Evenbratt, Hanne; Jonsson, Charlotte; Faergemann, Jan; Engström, Sven; Ericson, Marica B

    2013-08-16

    We demonstrate a rapidly formed cubic liquid crystalline phase, i.e. typically 1g cubic phase in less than 1 min confirmed by X-ray diffraction, consisting of an ether lipid, 1-glyceryl monooleyl ether (GME), an aprotic solvent (propylene glycol or pentane-1,5-diol) and water. The efficacy of the cubic formulation was tested in vivo by administrating formulations containing 3% (w/w) of the HCl salts of δ-aminolevulinic acid (ALA) or methylaminolevulinate (MAL) to hairless mice. The endogenous formation of protoporphyrin IX (PpIX) was monitored spectrophotometrically as a marker for cellular uptake of active compound. As reference, a commercial product containing 16% (w/w) MAL in an oil-in-water emulsion (Metvix(®)), and a cubic phase based on an ester lipid (glyceryl monooleate, GMO), previously shown to facilitate topical delivery of both ALA and MAL, were applied. It was found that in general the cubic phases gave rise to higher fluorescence levels than the mice exposed to the commercial product. The instantly formed cubic formulations based on GME demonstrated the same efficiency as the GMO based formulations. The results imply that instantly formed cubic formulations opens up new opportunities, particularly for transdermal drug delivery of substances subject to stability problems in, e.g. aqueous environments. PMID:23727140

  12. Effects of buccal nitrate on left ventricular haemodynamics and volume at rest and during exercise-induced angina.

    PubMed Central

    Silke, B; Verma, S P; Frais, M A; Hafizullah, M; Taylor, S H

    1985-01-01

    A novel approach has been employed to characterize the effects of a cardioactive drug on left ventricular haemodynamics and volume by simultaneously determining cardiac stroke volume (thermodilution) and left ventricular ejection fraction (nuclear probe). The effects of glyceryl trinitrate were evaluated in 12 patients with angiographically proven coronary artery disease at rest and 3, 7, 15 and 30 min following 10 mg buccal nitroglycerin (Suscard) administration. The impact of the drug on left ventricular haemodynamics and volume during exercise-induced angina was determined by repeating exercise 30 min following drug administration, at the workload that reliably induced angina during control exercise. At rest buccal nitroglycerin reduced systemic arterial pressure, cardiac and stroke volume indices, and increased heart rate. The left ventricular ejection fraction (E.F.) increased; its filling pressure together with end-diastolic and end-systolic volumes were significantly reduced. Compared with control supine-bicycle exercise, the drug reduced mean systemic arterial pressure and left ventricular filling pressure without change in cardiac and stroke volume indices. There was a smaller increase in left ventricular volume during exercise, and the fall in E.F. was attenuated. These data demonstrated differential actions of glyceryl trinitrate on left ventricular function related to the physiological state in obstructive coronary artery disease. These techniques appear to hold promise in the evaluation of the effects of other therapies on left ventricular volume in coronary artery disease. PMID:3935147

  13. Release of Methane from Bering Sea Sediments During the Last Glacial Period

    SciTech Connect

    Mea Cook; Lloyd Keigwin

    2007-11-30

    Several lines of evidence suggest that during times of elevated methane flux the sulfate-methane transition zone (SMTZ) was positioned near the sediment-water interface. We studied two cores (from 700 m and 1457 m water depth) from the Umnak Plateau region. Anomalously low d13C and high d18O in benthic and planktonic foraminifera in these cores are the consequence of diagenetic overgrowths of authigenic carbonates. There are multiple layers of authigenic-carbonate-rich sediment in these cores, and the stable isotope compositions of the carbonates are consistent with those formed during anaerobic oxidation of methane (AOM). The carbonate-rich layers are associated with biomarkers produced by methane-oxidizing archaea, archaeol and glyceryl dibiphytanyl glyceryl tetraether (GDGT). The d13C of the archaeol and certain GDGTs are isotopically depleted. These carbonate- and AOM-biomarker-rich layers were emplaced in the SMTZ during episodes when there was a high flux of methane or methane-rich fluids upward in the sediment column. The sediment methane in the Umnak Plateau region appears to have been very dynamic during the glacial period, and interacted with the ocean-atmosphere system at millennial time scales. The upper-most carbonate-rich layers are in radiocarbon-dated sediment deposited during interstitials 2 and 3, 28-20 ka, and may be associated with the climate warming during this time.

  14. Flavonolignans and other constituents from Lepidium meyenii with activities in anti-inflammation and human cancer cell lines.

    PubMed

    Bai, Naisheng; He, Kan; Roller, Marc; Lai, Ching-Shu; Bai, Lu; Pan, Min-Hsiung

    2015-03-11

    From the roots of Lepidium meyenii Walpers (Brassicaceae) have been isolated and identified 2 flavonolignans, tricin 4'-O-[threo-β-guaiacyl-(7″-O-methyl)-glyceryl] ether (1) and tricin 4'-O-(erythro-β-guaiacyl-glyceryl) ether (2), along with 11 other known compounds, tricin (3), pinoresinol (4), 4-hydroxycinnamic acid (5), guanosine (6), glucotropaeolin (7), desulfoglucotropaeolin (8), 3-hydroxybenzylisothiocyanate (9), malic acid benzoate (10), 5-(hydroxymethyl)-2-furfural (11), d-phenylalanine (12), and vanillic acid 4-O-β-d-glucoside (13). Structures were elucidated on the basis of NMR and MS data. Some isolates and previously isolated lepidiline B (14) were tested for cytotoxicity in a small panel of human cancer cell lines (Hep G2, COLO 205, and HL-60) and for anti-inflammatory activities in LPS-treated RAW 264.7 macrophage. Among them, compounds 1 and 14 were modestly active for inhibiting nitrite production in macrophage. Compounds 1, 14, and 3 were demonstrated to be selectively active against HL-60 cells with IC50 values of 40.4, 52.0, and 52.1 μM, respectively. PMID:25667964

  15. Nanosized self-emulsifying lipid vesicles of diacylglycerol-PEG lipid conjugates: Biophysical characterization and inclusion of lipophilic dietary supplements

    SciTech Connect

    Koynova, Rumiana; Tihova, Mariana

    2010-04-12

    Hydrated diacylglycerol-PEG lipid conjugates, glyceryl dioleate-PEG12 (GDO-PEG12) and glyceryl dipalmitate-PEG23 (GDP-PEG23), spontaneously form uni- or oligolamellar liposomes in their liquid crystalline phase, in distinct difference from the PEGylated phospholipids which form micelles. GDP-PEG23 exhibits peculiar hysteretic phase behavior and can arrange into a long-living hexagonal phase at ambient and physiological temperatures. Liposomes of GDO-PEG12 and its mixture with soy lecithin exchange lipids with the membranes much more actively than common lecithin liposomes; such an active lipid exchange might facilitate the discharging of the liposome cargo upon uptake and internalization, and can thus be important in drug delivery applications. Diacylglycerol-PEG lipid liposome formulations can encapsulate up to 20-30 wt.% lipophilic dietary supplements such as fish oil, coenzyme Q10, and vitamins D and E. The encapsulation is feasible by way of dry mixing, avoiding the use of organic solvent.

  16. Induction of primary, antiviral cytotoxic, and proliferative responses with antigens administered via dendritic cells.

    PubMed Central

    Nair, S; Babu, J S; Dunham, R G; Kanda, P; Burke, R L; Rouse, B T

    1993-01-01

    Cytotoxic T lymphocytes (CTL) play an essential role in recovery from viral infections, but induction of CTL responses with nonreplicating antigens is difficult to achieve. Exogenous antigens, such as viral proteins and peptides, normally induce CD4+ T-cell responses unless appropriately delivered to the major histocompatibility complex class I antigen presentation pathway. In vitro studies performed to address this issue revealed a similar scenario, and primary CTL induction with nonreplicating antigens has rarely been reported. This study demonstrated primary antiviral CTL induction in vitro with exogenous antigens delivered in vivo to dendritic cells. This study also evaluated the efficacy of glycoprotein B peptide (free or encapsulated in liposomes), peptide-tripalmitoyl-S-glyceryl cysteinyl conjugate (acylpeptide), and glycoprotein B protein encapsulated in pH-sensitive liposomes as antigen delivery vehicles. Our results show that higher levels of cytotoxicity against herpes simplex virus type 1 resulted from exposure of dendritic cells to peptide-tripalmitoyl-S-glyceryl cysteinyl in liposomes. Macrophages treated in a similar manner were not effective stimulators for primary CTL induction. Our data have relevance to the understanding of mechanisms of antigen processing and presentation and the design of antiviral vaccines. PMID:8510217

  17. Two new aliphatic lactones from the fruits of Coriandrum sativum L.

    PubMed Central

    2012-01-01

    Background The present paper describes the isolation and characterization of two new aliphatic δ-lactones along with three glycerides and n-nonadecanyl cetoleate from the fruits of Coriandrum sativum L. (Apiaceae). The structures of all the isolated phytoconstituents have been established on the basis of spectral data analysis and chemical reactions. Results Phytochemical investigation of the methanolic extract of C. sativum L. (Apiaceae) fruits resulted in the isolation of two new aliphatic δ-lactones characterized as 2α-n-heptatriacont-(Z)-3-en-1,5-olide (1) (coriander lactone) and 2α-n-tetracont-(Z,Z)-3,26-dien-18α-ol-1,5-olide (2) (hydroxy coriander lactone) together with glyceryl-1,2-dioctadec-9,12-dienoate-3-octadec-9-enoate (3); glyceryl-1,2,3-trioctadecanoate (4); n-nonadecanyl-n-docos-11-enoate (5) and oleiyl glucoside (6). Conclusions Phytochemical investigation of the methanolic extract of C. sativum gave coriander lactone and hydroxy coriander lactone as the new phytoconstituents. PMID:22800677

  18. Preparation and in vitro evaluation of salbutamol-loaded lipid microparticles for sustained release pulmonary therapy.

    PubMed

    Scalia, Santo; Salama, Rania; Young, Paul; Traini, Daniela

    2012-01-01

    The aim of this study was to prepare lipid microparticles (LMs) loaded with the polar bronchodilator agent salbutamol, and designed for sustained release pulmonary delivery. The microparticles were produced by melt emulsification followed by a sonication step, using different biocompatible lipid carriers (tristearin, stearic acid and glyceryl behenate) and phosphatidylcholine as the surfactant. The use of salbutamol free base, rather than salbutamol sulphate, was necessary to obtain the incorporation of the drug in the lipid particle matrix. The prolonged release of salbutamol base was achieved only by the glyceryl behenate microparticles (40.9% of encapsulated drug being released after 8 h). The salbutamol loading was 4.2% ± 0.1 and the mass median diameter, determined by laser diffraction, ranged from 4.8 to 5.4 µm. The sustained release of LMs were formulated as a carrier-free dry powder for inhalation and exhibited a fine particle fraction of 17.3% ± 2.2, as measured by multi-stage liquid impinger. PMID:22208706

  19. Safety Evaluation of Polyethylene Glycol (PEG) Compounds for Cosmetic Use

    PubMed Central

    Shin, Chan Young; Kim, Kyu-Bong

    2015-01-01

    Polyethylene glycols (PEGs) are products of condensed ethylene oxide and water that can have various derivatives and functions. Since many PEG types are hydrophilic, they are favorably used as penetration enhancers, especially in topical dermatological preparations. PEGs, together with their typically nonionic derivatives, are broadly utilized in cosmetic products as surfactants, emulsifiers, cleansing agents, humectants, and skin conditioners. The compounds studied in this review include PEG/PPG-17/6 copolymer, PEG-20 glyceryl triisostearate, PEG-40 hydrogenated castor oil, and PEG-60 hydrogenated castor oil. Overall, much of the data available in this review are on PEGylated oils (PEG-40 and PEG-60 hydrogenated castor oils), which were recommended as safe for use in cosmetics up to 100% concentration. Currently, PEG-20 glyceryl triisostearate and PEGylated oils are considered safe for cosmetic use according to the results of relevant studies. Additionally, PEG/PPG-17/6 copolymer should be further studied to ensure its safety as a cosmetic ingredient. PMID:26191379

  20. In vitro controlled release of colon targeted mesalamine from compritol ATO 888 based matrix tablets using factorial design

    PubMed Central

    Patel, J.K.; Patel, N.V.; Shah, S.H.

    2009-01-01

    A controlled release matrix formulation for mesalamine was designed and developed to achieve a 24 h release profile. Using compritol 888 ATO (glyceryl behenate) as an inert matrix-forming agent to control the release of mesalamine, formulation granules containing the solid dispersions were investigated. Pectin, a polysaccharide, was used as bacterial dependent polymer for colon targeting. The matrix tablets for these formulations were prepared by direct compression and their in vitro release tests were carried out. A 32 full factorial design was used for optimization by taking the amounts of glyceryl behenate (X1) and pectin (X2) as independent variables and percentage drug released at 2 (Q2), 16 (Q16) and 24 (Q24) h as dependent variables. Drug release from the matrix tablets formulations lasted for over 24 h. Images of the tablet surface and cross-section were characterized by scanning electron microscopy to show the formed pores and channels in the matrices. These may provide the release pathway for the inner embedded drugs. The co-mixing of polysaccharide pectin, into the waxy matrices played a meaningful role in targeting the tablets to colon. The drug release from the novel formulation may be attributed to the diffusion-controlled mechanism. The results of the full factorial design indicated that an optimum amount of compritol ATO 888 and a high amount of pectin favors the colon targeting and controlled release of mesalamine from dosage form. PMID:21589801

  1. Effect of Antiadherents on the Physical and Drug Release Properties of Acrylic Polymeric Films.

    PubMed

    Ammar, Hussein O; Ghorab, Mamdouh M; Felton, Linda A; Gad, Shadeed; Fouly, Aya A

    2016-06-01

    Antiadherents are used to decrease tackiness of a polymer coating during both processing and subsequent storage. Despite being a common excipient in coating formulae, antiadherents may affect mechanical properties of the coating film as well as drug release from film-coated tablets, but how could addition of antiadherents affect these properties and to what extent and is there a relation between the physical characteristics of the tablet coat and the drug release mechanisms? The aim of this study was to evaluate physical characteristics of films containing different amounts of the antiadherents talc, glyceryl monostearate, and PlasACRYL(TM) T20. Eudragit RL30D and Eudragit RS30D as sustained release polymers and Eudragit FS30D as a delayed release material were used. Polymer films were characterized by tensile testing, differential scanning calorimetry (DSC), microscopic examination, and water content as calculated from loss on drying. The effect of antiadherents on in vitro drug release for the model acetylsalicylic acid tablets coated with Eudragit FS30D was also determined. Increasing talc concentration was found to decrease the ability of the polymer films to resist mechanical stress. In contrast, glyceryl monostearate (GMS) and PlasACRYL produced more elastic films. Talc at concentrations higher than 25% caused negative effects, which make 25% concentration recommended to be used with acrylic polymers. All antiadherents delayed the drug release at all coating levels; hence, different tailoring of drug release may be achieved by adjusting antiadherent concentration with coating level. PMID:26314244

  2. Tackiness of acrylic and cellulosic polymer films used in the coating of solid dosage forms.

    PubMed

    Wesseling, M; Kuppler, F; Bodmeier, R

    1999-01-01

    The objective was to determine the tackiness of acrylic and cellulosic polymer films in order to make predictions on the tackiness (agglomeration) of coated dosage forms during coating and curing. Force-displacement curves of the detachment process of two polymeric films were used as a measure of tackiness. Various polymers (cellulosic (Aquacoat and acrylics (Eudragit RS 30D, L 30D, NE 30D)), plasticizers (triacetin, triethyl citrate, tributyl citrate, acetyltributyl citrate) and anti-tacking agents (talc and glyceryl monostearate) were investigated. The order of tackiness for films prepared from the different aqueous polymer dispersions was in order of Eudragit NE 30D > RS 30D > RL 30D > Aquacoat. The tackiness increased with increasing plasticizer concentration due to the softening of the polymer. A correlation between the minimum film formation temperature and the tackiness was observed, however, no correlation between the tackiness and the lipophilicity of the plasticizer was seen. Talc and glyceryl monostearate (GMS) reduced the tackiness of the films significantly, with GMS being effective at much lower concentrations. Curing of Eudragit RS 30D-coated theophylline beads at temperatures higher than 40 degrees C in an irreversible agglomeration of the beads and damage of the coating upon separation of the beads. This resulted in a faster release than with uncured beads. Blending the beads with talc just prior to the curing step eliminated the agglomeration and therefore film damage, even at a curing temperature of 60 degrees C. PMID:10234529

  3. Inability of two topical treatments to influence the course of experimentally induced dermatophytosis in cats.

    PubMed

    DeBoer, D J; Moriello, K A

    1995-07-01

    An experimental model of dermatophytosis was used to compare the efficacy of 2 topical antifungal treatments against Microsporum canis infection in cats. Infection was established in 24 cats by topical application of 10(5) M canis macroconidia to the skin of the lateral part of the abdomen under an occlusive bandage. Three groups of 6 cats each then were treated twice weekly for 18 weeks with chlorhexidine shampoo and dip, detergent shampoo vehicle only, or glyceryl monolaurate shampoo. Six cats were left untreated as controls. The experimentally induced infections strongly resembled naturally developing infections of moderate to severe nature. Signs of infection peaked in severity at 5 weeks after inoculation, then gradually resolved over 7 to 16 additional weeks. Dermatophytes were consistently isolated on culture for at least 8 weeks of treatment. Mycologic cure (defined as lack of dermatophyte isolation on 3 successive weekly cultures) was attained in 8 cats at the end of 18 weeks of treatment. Infections appeared to resolve at equivalent rates in all groups of cats, including controls. Consistent or meaningful significant differences in variables such as lesion size, clinical sign score, or total infection score were not found between treated and control groups. Our study revealed that this topical treatment regimen with chlorhexidine or glyceryl monolaurate is ineffective against M canis infection in cats. PMID:7601693

  4. Lipid microparticles as sustained release system for a GnRH antagonist (Antide).

    PubMed

    Del Curto, M D; Chicco, D; D'Antonio, M; Ciolli, V; Dannan, H; D'Urso, S; Neuteboom, B; Pompili, S; Schiesaro, S; Esposito, P

    2003-04-29

    Lipid microparticles (LMs) as a sustained release system for a gonadotropin release hormone (GnRH) antagonist (Antide) were prepared and evaluated. Antide loaded microparticles (Antide-LMs) were obtained by a cryogenic micronization process starting from two different monoglycerides (glyceryl monobehenate and glyceryl monostearate) and using two different incorporation methods (co-melting and solvent evaporation). Antide-LMs, 2% (w/w) loading, were characterized for drug incorporation by RP-HPLC, particle size by laser diffractometry and surface morphology by scanning electron microscopy. In vitro peptide release and in vitro biological activity were also studied. Serum Antide and testosterone levels, as pharmacodynamic marker, were assessed following subcutaneous administration in rats. Antide-LMs showed a mean diameter of approximately 30 micro m and variable Antide release depending on lipid matrix and incorporation method. In vivo experiments demonstrated that detectable Antide plasma levels were present, in the case of Antide-LMs based on Compritol E ATO obtained by co-melting procedure, for at least 30 days after dosing. Testosterone levels were consistent with prolonged pharmacokinetic profiles. In vitro release of Antide from LMs correlated well with the in vivo release. In conclusion, LMs can sustain the release of Antide for at least 1 month. The levels of the initial 'burst' and the extent of the pharmacodynamic effect can be influenced by the lipid characteristics and by process conditions. PMID:12711452

  5. Characterization of an Alkaline Family I.4 Lipase from Bacillus sp. W130-35 Isolated from a Tidal Mud Flat with Broad Substrate Specificity.

    PubMed

    Kim, Hee Jung; Jung, Won Kyeong; Lee, Hyun Woo; Yoo, Wanki; Kim, T Doohun; Kim, Hoon

    2015-12-28

    A gene encoding lipolytic enzyme, lip7-3, was isolated from Bacillus sp. W130-35 isolated from a tidal mud flat. The gene encoded a protein of 215 amino acids with a signal peptide composed of 34 amino acid residues. Lip7-3 belonged to the family I.4 lipase and showed its maximal activity at pH 9.0 and 60°C. Its activity increased in the presence of 30% methanol and, remarkably, increased as well to 154.6% in the presence of Ca(2+). Lip7-3 preferred pnitrophenyl octanoate (C8) as a substrate and exhibited broad specificity for short- to longchain fatty acid esters. Additionally, Lip7-3 showed a low degree of enantioselectivity for an S-enantiomer (e.g., (S)-methyl-3-hydroxy-2-methylpropionate). It efficiently hydrolyzed glyceryl tributyrate, but did not hydrolyze glyceryl trioleate, fish oil, or olive oil. Its substrate specificity and activation by the solvent might offer a merit to the biotechnological enzyme applications like transesterification in the production of biodiesel. PMID:26370800

  6. Dissimilarities between methylene blue and cyanide on relaxation and cyclic GMP formation in endothelium-intact intrapulmonary artery caused by nitrogen oxide-containing vasodilators and acetylcholine

    SciTech Connect

    Ignarro, L.J.; Harbison, R.G.; Wood, K.S.; Kadowitz, P.J.

    1986-01-01

    The objective of the present study was to ascertain whether cyanide shares the properties of methylene blue as a selective inhibitor of vascular smooth muscle relaxation elicited by agents that stimulate the formation of cyclic GMP. Experiments were performed with endothelium-intact rings prepared from bovine intrapulmonary artery. Methylene blue, a good inhibitor of soluble guanylate cyclase, antagonized both arterial relaxation and cyclic GMP accumulation in response to sodium nitroprusside, glyceryl trinitrate, S-nitroso-N-acetylpenicillamine and acetylcholine. In contrast, cyanide inhibited only the responses to sodium nitroprusside. Increasing concentrations of methylene blue depressed resting arterial levels of cyclic GMP and caused slowly developing but marked contractions whereas cyanide was without effect. Contractile responses to phenylephrine, potassium and U46619 were potentiated by methylene blue but not by cyanide. Preincubation of dilute solutions of cyanide containing sodium nitroprusside in oxygenated Krebs' buffer at 37 degrees C for 15 min before addition to bath chambers depressed relaxation and cyclic GMP accumulation caused by sodium nitroprusside markedly. Similar treatment of glyceryl trinitrate, however, failed to alter its effects in arterial rings. A chemical inactivation of sodium nitroprusside by cyanide appears to account for the specific inhibitory action of cyanide on arterial responses to sodium nitroprusside. This study indicates clearly that cyanide does not share the properties of methylene blue as an inhibitor of arterial relaxation elicited by vasodilators that stimulate cyclic GMP formation.

  7. Nanomicelle Based Peroral Delivery System for Enhanced Absorption and Sustained Release of 10-Hydrocamptothecin.

    PubMed

    Tian, Ye; Shi, Chenjun; Zhang, Xin; Sun, Yujiao; Wang, Juan; Zhang, Yuyang; Yang, Jingyu; Wang, Lihui; Wang, Linlin; Mao, Shirui

    2015-02-01

    An effective sustained-release peroral drug delivery system is needed for chemotherapy. Here, we show that such a system can be achieved by designing polymeric nanomicelles combining mucoadhesion, enhanced absorption and controlled release. Chitosan and glyceryl-monooleate have many desirable properties, so we synthesized a novel chitosan derivative, chitosan-conjugated glyceryl monooleate. We loaded 10-hydroxycamptothecin (HCPT) into the cores of nanomicelles by pH-coacervation, which significantly improved drug loading and stability. We studied the pharmacokinetics of these drug-loaded nanomicelles, and they demonstrated remarkably prolonged circulation time in vivo up to 72 h. Orally administered HCPT-loaded nanomicelles also showed comparable antitumor effects and smaller changes in body weight compared to HCPT administered by injection. Most importantly, by using in vivo pharmacokinetic and pharmacodynamic studies, we showed that comparable antitumor effects can be achieved by peroral administration of HCPT-loaded nanomicelles every three days, and that the nanomicelles had less severe side effects. In vivo imaging provided direct evidence that the micelles were absorbed and exhibited sustained release after oral administration. These results indicate a promising future for nanomicelle-based peroral drug delivery as a superior alternative to injection, and they also provide guiding principles for designing amphiphilic copolymers. PMID:26349302

  8. Mycosporine-like Amino Acids and Other Phytochemicals Directly Detected by High-Resolution NMR on Klamath (Aphanizomenon flos-aquae) Blue-Green Algae.

    PubMed

    Righi, Valeria; Parenti, Francesca; Schenetti, Luisa; Mucci, Adele

    2016-09-01

    This study describes for the first time the use of high-resolution nuclear magnetic resonance (NMR) on Klamath (Aphanizomenon flos-aquae, AFA) blue-green algae directly on powder suspension. These algae are considered to be a "superfood", due to their complete nutritional profile that has proved to have important therapeutic effects. The main advantage of NMR spectroscopy is that it permits the detection of a number of metabolites all at once. The Klamath alga metabolome was revealed to be quite complex, and the most peculiar phytochemicals that can be detected directly on algae by NMR are mycosporine-like amino acids (porphyra-334, P334; shinorine, Shi) and low molecular weight glycosides (glyceryl β-d-galactopyranoside, GalpG; glyceryl 6-amino-6-deoxy-α-d-glucopyranoside, ADG), all compounds with a high nutraceutical value. The presence of cis-3,4-DhLys was revealed for the first time. This molecule could be involved in the anticancer properties ascribed to AFA. PMID:27537083

  9. Porphyrins as Second Order Nonlinear Optical Materials

    NASA Astrophysics Data System (ADS)

    Chou, Homer

    Because of the unusually high thermal and chemical stability of porphyrins as well as their very large pi-conjugated systems, three classes of high beta-value push-pull porphyrins were synthesized and subsequently successfully engineered into Langmuir-Blodgett (LB) films for a systematic evaluation of porphyrins as chi^{(2)} materials. Class I explored the effects of the number of donor-acceptor groups on the porphyrin periphery (i.e., H_2(an_3P), H_2 (cis-a_2n_2P), H_2(a_3nP), H _2(a_4P) where a = 4-(N-octadecylamido)phenyl or 4-(N-octadecyl-amino)phenyl; n = 4-nitrophenyl; P = 5,10,15,20 substituted tetraarylporphyrinate (2-).). Class II examined the effect of varying the strength of cis-substituted donor-acceptor pairs on the porphyrin periphery (i.e., H_2(cis-a_2n _2P), H_2(cis-c _2p_2P), and H_2 (cis-h_2py_2P) where c = 4-(2-cholesteryloxy)-ethoxyphenyl; h = 4-hydroxyphenyl or 4-methoxyphenyl; and py = 4-pyridyl or 4-(N-octadecyl) pyridiniumyl). Class III looked at the respone of a heterosubstituted bis- push-pull cerium sandwich porphyrin complex, (Ce ^{IV}(TPyP)(TMeP)) ^{4+}I_4 (where Py = 4-(N-octadecyl)pyridiniumyl and Me = 4-methoxyphenyl). Characterization of the porphyrin LB films reveals rather surprising behavior. The isotherm data show that the mean molecular area of the porphyrins increase smoothly from 80-200A as the number of aliphatic chains increase around the porphyrin periphery from one to four. In addition, based on UV-visible linear dichroism, all of the porphyrin films possess C _{infty v} symmetry and adopt a tilt angle, theta, of about 33^circ with respect to the fused quartz substrate. The proposed fixed orientation model suggests that the interporphyrin pi -pi interactions dominate the porphyrin orientation while the number of aliphatic chains around the porphyrin periphery determines the porphyrin's packing density in the LB film. After these monolayers were transferred to fused quartz substrates, the chi^{(2)} response of these

  10. A new family of Langmuir-Blodgett films of tetracyanoquinodimethane charge transfer salts: Pristine and iodine doped conducting films

    NASA Astrophysics Data System (ADS)

    Vandevyer, M.; Richard, J.; Barraud, A.; Ruaudel-Teixier, A.; Lequan, M.; Lequan, R. M.

    1987-12-01

    A new family of semiamphiphilic tetracyanoquinodimethane (TCNQ) ionic salts of nonconjugated cations, namely octadecyl-dimethylsulfonium, octadecyl-methyl-ethyl-sulfonium, and octadecyl-trimethylphosphonium labeled a, b, and c, respectively, has been synthetized. Langmuir-Blodgett (LB) films are built up from these three compounds, which are mixed with octadecylurea in a molar ratio 1/1, in order to improve the stability of the film at the water surface. The structural properties of the transferred films are thoroughly investigated by linear dichroism in the IR and UV-visible ranges, together with ESR spectroscopy. In the films of the three compounds, the polar sheets contain (TCNQ- • )2 dimers, which are the largely prevalent species. The molecular planes of these dimers are found to be roughly parallel to the substrate. Moreover, a strong in-plane orientation of the dimers is found in films of compound c. This phenomenon is thought to be related to an overall flow orientation of rod-shaped crystallites in the floating film, during the high speed downstroke of the substrate across the film. Advantage is taken from the high and well-controlled thinness of LB films to make iodine vapor diffuse into the films and convert the precursor films into conducting ones. The iodination process leads for the three salts to a stable ternary conducting compound located in the polar planes of the LB assembly. Correlatively, it induces a strong molecular reorganization in the films: the TCNQ molecules stand on edge with their long molecular axis perpendicular to the substrate. In spite of this considerable rearrangement arising from iodination, we notice that the strong in-plane anisotropy observed in pristine films of c is retained in conducting films of the iodinated c compound. Beside these structural results, the IR spectra of conducting films are reminiscent of these of highly conducting, but not metallic-like, organic conductors. The conductivity of the films is estimated

  11. Multivariate assessment of lipophilicity scales-computational and reversed phase thin-layer chromatographic indices.

    PubMed

    Andrić, Filip; Bajusz, Dávid; Rácz, Anita; Šegan, Sandra; Héberger, Károly

    2016-08-01

    Needs for fast, yet reliable means of assessing the lipophilicities of diverse compounds resulted in the development of various in silico and chromatographic approaches that are faster, cheaper, and greener compared to the traditional shake-flask method. However, at present no accepted "standard" approach exists for their comparison and selection of the most appropriate one(s). This is of utmost importance when it comes to the development of new lipophilicity indices, or the assessment of the lipophilicity of newly synthesized compounds. In this study, 50 well-known, diverse compounds of significant pharmaceutical and environmental importance have been selected and examined. Octanol-water partition coefficients have been measured with the shake-flask method for most of them. Their retentions have been studied in typical reversed thin-layer chromatographic systems, involving the most frequently employed stationary phases (octadecyl- and cyano-modified silica), and acetonitrile and methanol as mobile phase constituents. Twelve computationally estimated logP-s and twenty chromatographic indices together with the shake-flask octanol-water partition coefficient have been investigated with classical chemometric approaches-such as principal component analysis (PCA), hierarchical cluster analysis (HCA), Pearson's and Spearman's correlation matrices, as well as novel non-parametric methods: sum of ranking differences (SRD) and generalized pairwise correlation method (GPCM). Novel SRD and GPCM methods have been introduced based on the Comparisons with One VAriable (lipophilicity metric) at a Time (COVAT). For the visualization of COVAT results, a heatmap format was introduced. Analysis of variance (ANOVA) was applied to reveal the dominant factors between computational logPs and various chromatographic measures. In consensus-based comparisons, the shake-flask method performed the best, closely followed by computational estimates, while the chromatographic estimates often

  12. Thermal and mechanical properties of bio-nanocomposites reinforced by Luffa cylindrica cellulose nanocrystals.

    PubMed

    Siqueira, Gilberto; Bras, Julien; Follain, Nadège; Belbekhouche, Sabrina; Marais, Stéphane; Dufresne, Alain

    2013-01-16

    Cellulose nanocrystals have been prepared by acid hydrolysis of Luffa cylindrica fibers. The acid-resistant residue consisted of rod-like nanoparticles with an average length an diameter around 242 and 5.2nm, respectively (aspect ratio around 46). These cellulose nanocrystals have been used as a reinforcing phase for the processing of bio-nanocomposites using polycaprolactone (PCL) as matrix. To promote interfacial filler/matrix interactions the surface of cellulose nanocrystals was chemically modified with n-octadecyl isocyanate (C(18)H(37)NCO). Evidence of the grafting was supported by infrared spectroscopy and elemental analysis. X-ray diffraction analysis was used to confirm the integrity of cellulose nanocrystals after chemical modification. Both unmodified and chemically modified nanocrystals were used to prepare nanocomposites. The thermal properties of these materials were determined from differential scanning calorimetry and their mechanical behavior was evaluated in both the linear and non-linear range. PMID:23121968

  13. Resonance energy transfer in a model system of membranes: application to gel and liquid crystalline phases.

    PubMed Central

    Loura, L M; Fedorov, A; Prieto, M

    1996-01-01

    Resonance energy transfer between octadecyl rhodamine B (donor) and 1,1',3,3,3',3'-hexamethylindotricarbocyanine (acceptor) was studied in a model system of membranes (large unilamellar vesicles of dipalmitoylphosphatidylcholine), using both steady-state and time-resolved techniques. In the fluid phase (temperature = 50 degrees C) the decay law and the steady-state theoretical curve for energy transfer in two dimensions are verified. In the gel phase (temperature = 25 degrees C) an apparent reduction of dimensionality is observed, which is explained on the basis of probe segregation to the defect lines (grain boundaries). An estimation of the domain size from the model recovered linear probe concentrations is approximately 1750-2000 lipid molecules. In both phases, the existence of a fractal geometry was ruled out. PMID:8889159

  14. Influence of the presence of small gas molecules in the structure of comblike polyacrylates: a Monte Carlo study.

    PubMed

    León, Salvador; Zanuy, David; Alemán, Carlos

    2002-05-01

    A theoretical strategy has been developed to study the motion of small molecules through ordered polymeric systems. The strategy, which has been incorporated into a computer program denoted MCDP/2, is especially useful to study comblike polymers organized in biphasic arrangements. This is because it is based on a configurational bias Monte Carlo algorithm, which is more efficient than conventional methods to study dense systems. The MCDP/2 program has been used to investigate the influence of CH(4) and CO(2) gas molecules in the structure of isotactic poly(octadecyl acrylate), a typical comblike polymer. For this purpose, the pure polymer and different molecular systems constituted by several gas molecules dissolved in the polymer matrix have been simulated. Results indicated that the structural relaxation of the polymer is not coupled to the motion of gas molecules. The importance of these results in the field of molecular modeling of transport properties in comblike polymers is discussed. PMID:11948586

  15. A Bilayered Structure Comprised of Functionalized Carbon Nanotubes for Desalination by Membrane Distillation.

    PubMed

    Bhadra, Madhuleena; Roy, Sagar; Mitra, Somenath

    2016-08-01

    The development of a novel carbon nanotube (CNT) immobilized membrane comprised of a double-layer structure is presented for water desalination by membrane distillation. The bilayered structure is comprised of CNTs functionalized with a hydrophobic octadecyl amine group on the feed side and carboxylated CNTs on the permeate side. The latter is more hydrophilic. The hydrophobic CNTs provide higher water vapor permeation, while the hydrophilic CNTs facilitate the condensation of water vapor. Together, these led to superior performance, and flux in a direct contact membrane distillation mode was found to be as high as 121 kg/m(2)h at 80 °C. The bilayered membrane represented an enhancement of 70% over the unmodified membrane and 37% over a membrane which had a monolayered structure where only the feed side was CNT-modified. PMID:27387851

  16. Determination of thiram in natural waters using flow-injection with cerium(IV)-quinine chemiluminescence system.

    PubMed

    Waseem, Amir; Yaqoob, Mohammad; Nabi, Abdul

    2010-01-01

    A simple and rapid flow-injection chemiluminescence method has been developed for the determination of dithiocarbamate fungicide thiram based on the chemiluminescence reaction of thiram with ceric sulfate and quinine in aqueous sulfuric acid. The present method allowed the determination of thiram in the concentration range of 7.5-2500 ng/mL and the detection limit (signal-to-noise ratio = 3) was 7.5 ng/mL with sample throughput of 120/h. The relative standard deviation was 2.5% for 10 replicate analyses of 500 ng/mL thiram. The effects of foreign species including various anions and cations present in water at environmentally relevant concentrations and some pesticides were also investigated. The proposed method was applied to determine thiram in spiked natural waters using octadecyl bonded phase silica (C(18)) cartridges for solid-phase extraction. The recoveries were in the range 99 +/- 1 to 104 +/- 1%. PMID:19630089

  17. Charge-conversional poly(amino acid)s derivatives as a drug delivery carrier in response to the tumor environment.

    PubMed

    Yoon, Se Rim; Yang, Hee-Man; Park, Chan Woo; Lim, Sujin; Chung, Bong Hyun; Kim, Jong-Duk

    2012-08-01

    A charge-converting and pH-dependent nanocarrier was achieved by conjugating 2,3-dimethylmaleic anhydride (DMMA) to the amino group of an octadecyl grafted poly (2-hydroxyethyl aspartamide) (PHEA-g-C(18)-NH(2)) backbone, thereby forming a spherical micelle. PHEA, a poly(amino acid)s derivative, was derived from poly(succinimide), which is biocompatible and biodegradable. DMMA, a detachable component at the tumor site, was added, preventing aggregation with negative blood serum and enhancing the nanocarrier's cellular uptake. The polymeric micelle was comprehensively characterized and doxorubicin was encapsulated successively. The cellular uptake and anticancer therapeutic effect were evaluated by flow cytometry, confocal laser scanning microscopy, and a MTT assay. The properties of the nanocarrier can further be exploited to develop an early detection module for cancer. The present work is also expected to advance the study of designing smart carriers for drug and gene delivery. PMID:22581644

  18. Porosity in Polysilsesquioxane Xerolgels

    SciTech Connect

    Baugher, B.M.; Loy, D.A.; Rahimian, K.

    1999-08-17

    Polymerization of organotrialkoxysilanes is a convenient method for introducing organic functionality into hybrid organic-inorganic materials. However, not much is known about the effects of the organic substituent on the porosity of the resulting xerogels. In this study, we prepared a series of polysilsesquioxane xerogels from organotrialkoxysilanes, RSi(OR{sup 1}){sub 3}, with different organic groups (R = H, Me, Et dodecyl, hexadecyl, octadecyl, vinyl, chloromethyl, (p-chloromethyl) phenyl, cyanoethyl). Polymerizations of the monomers were carried out under a variety of conditions, varying monomer concentration, type of catalyst, and alkoxide substituent. The effect of the organic substituent on the sol-gel process was often dramatic. In many cases, gels were formed only at very high monomer concentration and/or with only one type of catalyst. All of the gels were processed as xerogels and characterized by scanning electron microscopy and nitrogen sorption porosimetry to evaluate their pore structure.

  19. Two-dimensional liquid chromatography (LC) of phenolic compounds from the shoots of Rubus idaeus 'Glen Ample' cultivar variety.

    PubMed

    Kula, Marta; Głód, Daniel; Krauze-Baranowska, Mirosława

    2016-03-20

    In this study the application of two-dimensional LC (2D LC) for qualitative analysis of polyphenols and simple phenols in the shoots of Rubus idaeus 'Glen Ample' variety is presented. In the preliminary analysis, the methanol extract of the shoots was analyzed by one-dimensional LC. One-dimensional LC separation profiles of phenolics from R. idaeus 'Glen Ample' shoots were dependent on column type, mobile phase composition and gradient program used. Two-dimensional LC system was built from connecting an octadecyl C-18 silica column in the first dimension and pentafluorophenyl column in the second dimension, coupled with DAD and MS (ESI, APCI, DUIS ionization) detectors. A total of 34 phenolic compounds belonging to the groups of phenolic acids, ellagitannins, flavan-3-ols, flavonols and ellagic acid conjugates were identified in the shoots of R. idaeus 'Glen Ample'. The established 2D LC method offers an effective tool for analysis of phenolics present in Rubus species. PMID:26799975

  20. Determination of selected azaarenes in water by bonded-phase extraction and liquid chromatography

    USGS Publications Warehouse

    Steinheimer, T.R.; Ondrus, M.G.

    1986-01-01

    A method for the rapid and simple quantitative determination of quinoline, isoquinoline, and five selected three-ring azaarenes in water has been developed. The azaarene fraction is separated from its carbon analogues on n-octadecyl packing material by edition with acidified water/acetonitrile. Concentration as great as 1000-fold is achieved readily. Instrumental analysis involves high-speed liquid chromatography on flexible-walled, wide-bore columns with fluorescence and ultraviolet detection at several wavelengths employing filter photometers in series. Method-validation data is provided as azaarene recovery efficiency from fortified samples. Distilled water, river water, contaminated ground water, and secondary-treatment effluent have been tested. Recoveries at part-per-billion levels are nearly quantitative for the three-ring compounds, but they decrease for quinoline and isoquinoline. ?? 1986 American Chemical Society.

  1. Bacteria-mimicking nanoparticle surface functionalization with targeting motifs

    NASA Astrophysics Data System (ADS)

    Lai, Mei-Hsiu; Clay, Nicholas E.; Kim, Dong Hyun; Kong, Hyunjoon

    2015-04-01

    In recent years, surface modification of nanocarriers with targeting motifs has been explored to modulate delivery of various diagnostic, sensing and therapeutic molecular cargo to desired sites of interest in in vitro bioengineering platforms and in vivo pathologic tissue. However, most surface functionalization approaches are often plagued by complex chemical modifications and effortful purifications. To resolve such challenges, this study demonstrates a unique method to immobilize antibodies that can act as targeting motifs on the surfaces of nanocarriers, inspired by a process that bacteria use for immobilization of the host's antibodies. We hypothesized that alkylated Staphylococcus aureus protein A (SpA) would self-assemble with micelles and subsequently induce stable coupling of antibodies to the micelles. We examined this hypothesis by using poly(2-hydroxyethyl-co-octadecyl aspartamide) (PHEA-g-C18) as a model polymer to form micelles. The self-assembly between the micelles and alkylated SpA became more thermodynamically favorable by increasing the degree of substitution of octadecyl chains to PHEA-g-C18, due to a positive entropy change. Lastly, the mixing of SpA-PA-coupled micelles with antibodies resulted in the coating of micelles with antibodies, as confirmed with a fluorescence resonance energy transfer (FRET) assay. The micelles coated with antibodies to VCAM-1 or integrin αv displayed a higher binding affinity to substrates coated with VCAM-1 and integrin αvβ3, respectively, than other controls, as evaluated with surface plasmon resonance (SPR) spectroscopy and a circulation-simulating flow chamber. We envisage that this bacteria-inspired protein immobilization approach will be useful to improve the quality of targeted delivery of nanoparticles, and can be extended to modify the surface of a wide array of nanocarriers.In recent years, surface modification of nanocarriers with targeting motifs has been explored to modulate delivery of various

  2. Mesoporous organosilicas functionalized by alkyl groups: Synthesis, structure and adsorption properties

    NASA Astrophysics Data System (ADS)

    Barczak, M.; Dąbrowski, A.; Iwan, M.; Rzączyńska, Z.

    2009-01-01

    Mesoporous organosilicas were synthesized by sol-gel co-condensation of tetraethoxysilane and appropriate alkoxysilanes in the presence of Pluronic P123 surfactant. Hexyl, dodecyl, and octadecyl alkyl chains have been incorporated into mesopores by such co-condensation. Obtained materials were characterized by X-ray diffraction, FTIR spectroscopy, nitrogen adsorption measurements and thermogravimetry. Two resulted materials have highly ordered SBA-15 structure (p6m symmetry), other two are less ordered. All the materials exhibit well-developed porous structure (surface areas 500 to 830m2/g, pore volumes 0.65-1.32 cm3/g) and a high content of organic pendant groups introduced during co-condensation. All materials are thermally stable to 180°C, after that thermal decomposition of alkyl pendant groups starts.

  3. Determination of the new anticancer agent KW 2149, 7-N-[2-[2-(gamma-L-glutamylamino)ethyl)dithio)ethyl]mitomycin C, an analogue of mitomycin C.

    PubMed

    Pattyn, G; van Oosterom, A T; de Bruijn, E A; Tjaden, U R

    1991-03-01

    The new mitomycin 7-N-[2-[2-(gamma-L-glutamylamino)ethyl)dithio)ethyl] mitomycin C (KW 2149) (I) proved to be active against a wide variety of experimental tumours. In order to perform pharmacokinetic studies with the new drug in Phase I sessions, a fast and reliable method has been developed based on the data of previous assays for mitomycin C. XAD-2 was preferred for isolation of I from blood plasma. The recovery of I was 50% whereas that of mitomycin C was 85%. Optimal separation was obtained on octadecyl silica columns with methanol-water (45:55, v/v) as mobile phase, while ultraviolet absorbance detection was performed at 375 nm. The assay enabled determination of I in a plasma concentration range of 20-1000 ng/ml using porfiromycin as internal standard. PMID:1860933

  4. Determination of benzo(a)pyrene in the total particulate matter of cigarette smoke

    SciTech Connect

    Risner, C.H.

    1988-03-01

    A procedure for the isolation and determination of benzo(a)pyrene in the total particulate matter of cigarette smoke is described. Two high-pressure liquid chromatographic (HPLC) techniques are employed: a normal-phase, mu Bondapak-NH2, amino column is used for isolation of the benzo(a)pyrene fraction and a reversed-phase, Vydac 201TP54, polymeric octadecyl silane column is used for quantitation. Fluorescence detection is used in both modes of chromatography. The wavelengths of excitation and emission are evaluated for analytical detection. Extraction media and various isolation techniques are compared for their extraction efficiency and isolation from interferences, respectively. The procedure is efficient, reproducible, sensitive (3 pg), and gives results that compare favorably with other techniques reported in the literature for the B(a)P content of reference cigarettes, 1R1 and 1R4F.

  5. Infrared and Raman spectroscopic characterization of some organic substituted hybrid silicas

    NASA Astrophysics Data System (ADS)

    Capeletti, Larissa B.; Baibich, Ione M.; Butler, Ian S.; dos Santos, João H. Z.

    2014-12-01

    Nine hybrid silicas bearing the organic substituent groups methyl, octyl, octadecyl, vinyl, phenyl, mercaptopropyl, isocyanatopropyl, chloropropyl and glycidoxypropyl were synthesized by an acid-catalyzed, hydrolytic sol-gel process. The resulting solid materials were characterized by their absorbance and attenuated total reflection (ATR) IR and Raman spectra. The latter technique proved to be particularly useful in the identification of the organic moieties in the hybrid silicas. The effect of the presence of the organic groups on the silica networks was also investigated - there were increases observed in both the Sisbnd Osbnd Si bond angles and bond lengths. Moreover, deconvolution of the IR-active antisymmetric Sisbnd Osbnd Si stretching bands permitted detection of the four- and six-membered siloxane rings present in the silicas. There proved to be a greater number of four-membered rings on the surfaces of the particles. Both IR and Raman spectroscopy proved to be invaluable in the characterization of these hybrid materials.

  6. Effect of coverage density and structure of chemically bonded silica stationary phases on the separation of compounds with various properties.

    PubMed

    Buszewski, Bogusław; Krupczyńska, Katarzyna; Rychlicki, Gerhard; Lobiński, Ryszard

    2006-04-01

    The chemical character, geometry, and architecture of chemically formed surface layers determine interactions between stationary phase, analyte, and mobile phase, and therefore the retention mechanisms (partitioning, adsorption, ion exchange, steric exclusion) of separated analytes. These interactions also depend on the structure and chemical character of the solutes and the composition of the mobile phase. High-molecular-weight fullerenes (C60 and C70) and water-soluble selenium-containing peptides (833 and 2607 Da) were used for the evaluation of laboratory-prepared octadecyl stationary phases with high and low coverage density before and after end-capping. The aim of this work was to study differences in surface coverage density and homogeneity and conformational changes of chemically bonded moieties and the influence of these parameters on the separation of mixtures of selenopeptides and fullerenes with significantly different molecular masses. A topographical model of the chemically modified stationary surface is presented. PMID:16830495

  7. Three New Isoprenylated Flavonoids from the Root Bark of Morus alba.

    PubMed

    Jung, Jae-Woo; Park, Ji-Hae; Lee, Yeong-Geun; Seo, Kyeong-Hwa; Oh, Eun-Ji; Lee, Dae-Young; Lim, Dong-Wook; Han, Daeseok; Baek, Nam-In

    2016-01-01

    Phytochemical investigation of the root bark of Morus alba has led to the isolation and identification of three new isoprenylated flavonoids, namely sanggenon U (1), sanggenon V (2), and sanggenon W (3), along with four known isoprenylated flavonoids: euchrenone a₇ (4), sanggenon J (5), kuwanon E (6), and kuwanon S (7). All compounds were isolated by repeated silica gel (SiO₂), octadecyl SiO₂ (ODS), and Sephadex LH-20 open column chromatography. The structure of the compounds were determined based on spectroscopic analyses, including nuclear magnetic resonance (NMR), mass spectrometry (MS), circular dichroism (CD), and infrared (IR). In addition, compounds 1-4 were isolated for the first time from the root bark of M. alba in this study. PMID:27563860

  8. Mixed Langmuir monolayers of an amphiphilic chromo-ionophore and the phospholipid DMPC

    NASA Astrophysics Data System (ADS)

    Sergeeva, T. I.; Gromov, S. P.; Vedernikov, A. I.; Kapichnikova, M. S.; Alfimov, M. V.; Möbius, D.; Zaitsev, S. Yu.

    2005-06-01

    The amphiphilic chromo-ionophore 2-[(1E,3E)-4-(2,3,5,6,8,9,11,12,14,15-decahydro-1,7,10,16,4,13-benzotetraoxadithiacyclooctadecin-18-yl)-1,3-butadienyl]-3-octadecyl-1,3-benzothiazol-3-ium perchlorate (AB211) forms mixed monolayers at the air-water interface with the phospholipid L-α-dimyristoylphosphatidylcholine (DMPC) as deduced from surface pressure-area and surface potential-area isotherms. In contrast to the behaviour of pure monolayers of AB211 on water, no association of the chromophores is observed by reflection spectroscopy. Upon compression of the mixed monolayer AB211:DMPC = 1:5, a re-orientation of the chromophores from flat to tilted is observed, presumably assisted by the stretching of the choline group of the phospholipid molecules acting a matrix.

  9. Composition and method for encapsulating photovoltaic devices

    DOEpatents

    Pern, Fu-Jann

    2000-01-01

    A composition and method for encapsulating a photovoltaic device which minimizes discoloration of the encapsulant. The composition includes an ethylene-vinyl acetate encapsulant, a curing agent, an optional ultraviolet light stabilizer, and/or an optional antioxidant. The curing agent is preferably 1,1-di-(t-butylperoxy)-3,3,5-trimethylcyclohexane; the ultraviolet light stabilizer is bis-(N-octyloxy-tetramethyl) piperidinyl sebacate and the antioxidant is selected from the group consisting of tris (2,4-di-tert-butylphenyl) phosphite, tetrakis methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) methane, octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, and 2,2'-ethylidene bis(4,6-di-t-butylphenyl) fluorophosponite. The composition is applied to a solar cell then cured. The cured product contains a minimal concentration of curing-generated chromophores and resists UV-induced degradation.

  10. Characterisation of Stevia rebaudiana by comprehensive two-dimensional liquid chromatography time-of-flight mass spectrometry.

    PubMed

    Pól, Jaroslav; Hohnová, Barbora; Hyötyläinen, Tuulia

    2007-05-25

    Comprehensive two-dimensional liquid chromatography (LC x LC) connected on-line to electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS) was employed for analysis of aqueous extract of Stevia rebaudiana. Different combinations of strong cation-exchange (SCX), amino (NH2), and octadecyl siloxane (C18) stationary phases were tested in the separation of all nine known sweet Stevia glycosides. A combination of C18 as the first-dimension column and NH2 as the second-dimension column fully separated all the glycosides from the matrix. The method proved to be quantitative and repeatable. The limit of detection (S/N=3) for stevioside, a widely used natural sweetener, was 43.4 ng/g in dry leaves. The RSD for retention times was <0.1% and that of peak areas 4.5%. PMID:16996528