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Sample records for glycyrrhetinate glycyrrhetinyl stearate

  1. Final report on the safety assessment of Glycyrrhetinic Acid, Potassium Glycyrrhetinate, Disodium Succinoyl Glycyrrhetinate, Glyceryl Glycyrrhetinate, Glycyrrhetinyl Stearate, Stearyl Glycyrrhetinate, Glycyrrhizic Acid, Ammonium Glycyrrhizate, Dipotassium Glycyrrhizate, Disodium Glycyrrhizate, Trisodium Glycyrrhizate, Methyl Glycyrrhizate, and Potassium Glycyrrhizinate.

    PubMed

    2007-01-01

    Glycyrrhetinic Acid and its salts and esters and Glycyrrhizic Acid and its salts and esters are cosmetic ingredients that function as flavoring agents or skin-conditioning agents - miscellaneous or both. These chemicals may be isolated from licorice plants. Glycyrrhetinc Acid is described as at least 98% pure, with 0.6% 24-OH-Glycyrrhetinic Acid, not more than 20 mu g/g of heavy metals and not more than 2 mu g/g of arsenic. Ammonium Glycyrrhizate has been found to be at least 98% pure and Dipotassium Glycyrrhizate has been found to be at least 95% pure. Glycyrrhetinic Acid is used in cosmetics at concentrations of up to 2%; Stearyl Glycyrrhetinate, up to 1%; Glycyrrhizic Acid, up to 0.1%; Ammonium Glycyrrhizate, up to 5%; Dipotassium Glycyrrhizate, up to 1%; and Potassium Glycyrretinate, up to 1%. Although Glycyrrhizic Acid is poorly absorbed by the intestinal tract, it may be hydrolyzed to Glycyrrhetinic Acid by a beta -glucuronidase produced by intestinal bacteria. Glycyrrhetinic Acid and Glycyrrhizic Acid bind to rat and human albumin, but do not absorb well into tissues. Glycyrrhetinic Acid and Glycyrrhizic Acid and metabolites are mostly excreted in the bile, with very little excreted in urine. Dipotassium Glycyrrhizate was undetectable in the receptor chamber when tested for transepidermal permeation through pig skin. Glycyrrhizic Acid increased the dermal penetration of diclofenac sodium in rat skin. Dipotassium Glycyrrhizate increased the intestinal absorption of calcitonin in rats. In humans, Glycyrrhetinic Acid potentiated the effects of hydrocortisone in the skin. Moderate chronic or high acute exposure to Glycyrrhizic Acid, Ammonium Glycyrrhizate, and their metabolites have been demonstrated to cause transient systemic alterations, including increased potassium excretion, sodium and water retention, body weight gain, alkalosis, suppression of the renin-angiotensis-aldosterone system, hypertension, and muscular paralysis; possibly through inhibition of

  2. Antibacterial Effects of Glycyrrhetinic Acid and Its Derivatives on Staphylococcus aureus

    PubMed Central

    Oyama, Kentaro; Kawada-Matsuo, Miki; Oogai, Yuichi; Hayashi, Tetsuya; Nakamura, Norifumi; Komatsuzawa, Hitoshi

    2016-01-01

    Staphylococcus aureus is a major pathogen in humans and causes serious problems due to antibiotic resistance. We investigated the antimicrobial effect of glycyrrhetinic acid (GRA) and its derivatives against 50 clinical S. aureus strains, including 18 methicillin-resistant strains. The minimum inhibitory concentrations (MICs) of GRA, dipotassium glycyrrhizate, disodium succinoyl glycyrrhetinate (GR-SU), stearyl glycyrrhetinate and glycyrrhetinyl stearate were evaluated against various S. aureus strains. Additionally, we investigated the bactericidal effects of GRA and GR-SU against two specific S. aureus strains. DNA microarray analysis was also performed to clarify the mechanism underlying the antibacterial activity of GR-SU. We detected the antimicrobial activities of five agents against S. aureus strains. GRA and GR-SU showed strong antibacterial activities compared to the other three agents tested. At a higher concentration (above 2x MIC), GRA and GR-SU showed bactericidal activity, whereas at a concentration of 1x MIC, they showed a bacteriostatic effect. Additionally, GRA and GR-SU exhibited a synergistic effect with gentamicin. The expression of a large number of genes (including transporters) and metabolic factors (carbohydrates and amino acids) was altered by the addition of GR-SU, suggesting that the inhibition of these metabolic processes may influence the degree of the requirement for carbohydrates or amino acids. In fact, the requirement for carbohydrates or amino acids was increased in the presence of either GRA or GR-SU. GRA and GR-SU exhibited strong antibacterial activity against several S. aureus strains, including MRSA. This activity may be partly due to the inhibition of several pathways involved in carbohydrate and amino acid metabolism. PMID:27820854

  3. Cation-controlled crystal growth of silver stearate: cryo-TEM investigation of lithium vs sodium stearate.

    PubMed

    Dong, Jingshan; McCormick, Alon V; Davis, H Ted; Whitcomb, David R

    2010-02-16

    Cryo-TEM, SAXS, and light microscopy techniques were used to probe the morphology and kinetics of silver stearate self-assembly and crystallization from the reaction of silver nitrate with lithium stearate. Unlike the reaction of sodium stearate with silver nitrate, which proceeds via micelle aggregation, the lithium stearate forms vesicles that drastically change the reaction kinetics of the silver stearate nucleation and self-assembly process. In addition, even with excess silver nitrate present, only about 80% of the lithium stearate can be converted to silver stearate. The presence of the residual lithium stearate inhibits the silver stearate crystal growth process. Consequently, no silver stearate micelle aggregates of any significant size form, unlike the system utilizing sodium stearate. Instead, significantly smaller silver stearate crystals result from lithium stearate compared to the silver stearate crystals from sodium stearate and provide an opportunity to further control silver stearate self-assembly and crystal growth.

  4. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Feed-grade calcium stearate and sodium stearate...

  5. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Feed-grade calcium stearate and sodium stearate...

  6. 21 CFR 182.8994 - Zinc stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Zinc stearate. 182.8994 Section 182.8994 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chickedema factor. (b) Conditions of use. This...

  7. 21 CFR 582.5994 - Zinc stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Zinc stearate. 582.5994 Section 582.5994 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chick...

  8. 21 CFR 182.8994 - Zinc stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Zinc stearate. 182.8994 Section 182.8994 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chickedema factor. (b) Conditions of use. This...

  9. 21 CFR 182.8994 - Zinc stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Zinc stearate. 182.8994 Section 182.8994 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chickedema factor. (b) Conditions of use. This...

  10. 21 CFR 582.5994 - Zinc stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Zinc stearate. 582.5994 Section 582.5994 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chick...

  11. 21 CFR 582.5994 - Zinc stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Zinc stearate. 582.5994 Section 582.5994 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chick...

  12. 21 CFR 582.5994 - Zinc stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Zinc stearate. 582.5994 Section 582.5994 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chick...

  13. 21 CFR 182.8994 - Zinc stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Zinc stearate. 182.8994 Section 182.8994 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8994 Zinc stearate. (a) Product. Zinc stearate prepared from...

  14. 21 CFR 582.5994 - Zinc stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Zinc stearate. 582.5994 Section 582.5994 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chick...

  15. 21 CFR 182.8994 - Zinc stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Zinc stearate. 182.8994 Section 182.8994 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8994 Zinc stearate. (a) Product. Zinc stearate prepared from stearic acid free from chickedema factor. (b) Conditions of use. This...

  16. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  17. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  18. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  19. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  20. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by the addition of an...

  1. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as... of this ingredient as generally recognized as safe (GRAS) as a direct human food ingredient is...

  2. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRINKING WATER OF ANIMALS Food Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate... calcium or sodium salts of a fatty acid mixture that is predominately stearic acid. Associated fatty acids, including palmitic acid and minor amounts of lauric, myristic, pentadecanoic, margaric, arachidic, and other...

  3. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRINKING WATER OF ANIMALS Food Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate... calcium or sodium salts of a fatty acid mixture that is predominately stearic acid. Associated fatty acids, including palmitic acid and minor amounts of lauric, myristic, pentadecanoic, margaric, arachidic, and other...

  4. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRINKING WATER OF ANIMALS Food Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate... calcium or sodium salts of a fatty acid mixture that is predominately stearic acid. Associated fatty acids, including palmitic acid and minor amounts of lauric, myristic, pentadecanoic, margaric, arachidic, and other...

  5. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium stearate. 184.1229 Section 184.1229 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...

  6. Characterization of Lithium Stearate: Processing Aid for Filled Elastomers

    SciTech Connect

    E. Eastwood; C. Densmore

    2007-02-05

    This topical report presents work completed to characterize lithium stearate so a replacement supplier could be identified. Lithium stearate from Alfa Aesar and Chemtura was obtained and characterized along with the current material from Witco. Multiple methods were used to characterize the materials including Karl Fischer, FT-IR, differential scanning calorimetry, and thermogravimetric analysis.

  7. Preparation and Physical Properties of Starch Stearates of Low to High Degree of Substitution

    USDA-ARS?s Scientific Manuscript database

    Starch stearates of degree of substitution (DS) 0.07-2.40 were prepared by heating dry starch and vinyl stearate in the ionic liquid BMIM dca at 75 Degrees C. Starch stearate of low DS (0.07) was insoluble in water but formed a gel and absorbed over seven times its weight of water. Starch stearate...

  8. 21 CFR 178.3690 - Pentaerythritol adipate-stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... Pentaerythritol adipate-stearate has the following specifications: (1) Melting point (dropping) of 55-58 °C as determined by ASTM method D566-76 (Reapproved 1982), “Standard Test Method for Dropping Point of Lubricating...

  9. Chemical modifications of natural triterpenes - glycyrrhetinic and boswellic acids: evaluation of their biological activity

    PubMed Central

    Subba Rao, G. S. R.; Kondaiah, Paturu; Singh, Sanjay K.; Ravanan, Palaniyandi; Sporn, Michael B.

    2008-01-01

    Synthetic analogues of naturally occurring triterpenoids; glycyrrhetinic acid, arjunolic acid and boswellic acids, by modification of A-ring with a cyano- and enone- functionalities, have been reported. A novel method of synthesis of α-cyanoenones from isoxazoles is reported. Bio-assays using primary mouse macrophages and tumor cell lines indicate potent anti-inflammatory and cytotoxic activities associated with cyanoenones of boswellic acid and glycyrrhetinic acid. PMID:20622928

  10. Metabolism of glycyrrhetic acid by rat liver microsomes: glycyrrhetinate dehydrogenase.

    PubMed

    Akao, T; Akao, T; Kobashi, K

    1990-02-06

    Glycyrrhetic acid, derived from a main component of liquorice, was converted to 3-ketoglycyrrhetic acid reversibly by rat liver homogenates in the presence of NADPH or NADP+. Glycyrrhetic acid-oxidizing and 3-ketoglycyrrhetic acid-reducing activities were localized in microsomes among the subcellular fractions of rat liver. Glycyrrhetic acid-oxidizing activity and 3-ketoglycyrrhetic acid-reducing activities showed pH optima at 6.3 and 8.5, respectively, and required NADP+ or NAD+ and NADPH or NADH, respectively, indicating that these activities were due to glycyrrhetinate dehydrogenase. The dehydrogenase was not solubilized from the membranes by the treatment with 1 M NaCl or sonication, indicating that the enzyme is a membrane component. The dehydrogenase was solubilized with detergents such as Emalgen 913, Triton X-100 and sodium cholate, and then separated from 3 beta-hydroxysteroid dehydrogenase (5 beta-androstan-3 beta-ol-17-one-oxidizing activity) by butyl-Toyopearl 650 M column chromatography. Partially purified enzyme catalyzed the reversible reaction between glycyrrhetic acid and 3-ketoglycyrrhetic acid, but was inactive toward 3-epiglycyrrhetic acid and other steroids having the 3 beta-hydroxyl group. The enzyme required NADP+ and NADPH for the highest activities of oxidation and reduction, respectively, and NAD+ and NADH for considerable activities, similar to the results with microsomes. From these results the enzyme is defined as glycyrrhetinate dehydrogenase, being quite different from 3 beta-hydroxysteroid dehydrogenase of Ruminococcus sp. from human intestine, which is active for both glycyrrhetic acid and steroids having the 3 beta-hydroxyl group.

  11. Discovery of glycyrrhetinic acid as an orally active, direct inhibitor of blood coagulation factor xa.

    PubMed

    Jiang, Lilong; Wang, Qiong; Shen, Shu; Xiao, Tongshu; Li, Youbin

    2014-03-01

    Factor Xa (FXa) plays an important role in blood coagulation. This study investigated glycyrrhetinic acid, a small molecule derived from Chinese herbs, and whether it has a direct inhibitory effect on FXa to display its anticoagulant activity. Enzyme activities of FXa, plasmin, trypsin and thrombin, inhibition of FXa enzyme kinetics and plasma clotting time by glycyrrhentinic acid were performed in vitro. A rat tail-bleeding model and a rat venous stasis model were also used to evaluate in vivo tail-bleeding time and thrombus formation, respectively. Glycyrrhetinic acid in vitro directly inhibited FXa uncompetitivly with IC50 of 32.6 ± 1.24 μmol/L, and displayed 2-, 14- and 20-fold selectivity for FXa when compared to plasmin, thrombin and trypsin, respectively. The plasma clotting time was increased in a dose-dependent manner. The prothrombin time doubled (PT2), when the concentration of glycyrrhetinic acid reached 2.02 mmol/L. During in vivo experiments intragastric administration of glycyrrhetinic acid caused a dose-dependent reduction in thrombus weight on the rat venous stasis model (all P<0.05). 50 mg/kg glycyrrhetinic acid resulted in 34.8% of venous thrombus weight lost, compared to the control. In addition, 200, 300 and 400 mg/kg doses of glycyrrhetinic acid caused a moderate hemorrhagic effect in the rat tail-bleeding model by prolonging bleeding time 1.1-, 1.5- and 1.9-fold compared to the control, respectively. Glycyrrhetinic acid is a direct inhibitor of FXa that is effective by oral administration, and with further research could be used to treat blood coagulation disorders. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Synthesis and properties of phosphono-derivatives of methyl stearate

    USDA-ARS?s Scientific Manuscript database

    A series of phosphono-derivatives of methyl stearate (PhDMS) were synthesized from methyl oleate and dialkyl H-phosphonates (dialkyl-phosphites). The alkyl groups in the phosphonates were methyl, ethyl, and butyl. The reaction can be carried to 98+% completion with a radical initiator. It is possibl...

  13. Characterization of TiO2 nanoparticles surface modified with aluminum stearate.

    PubMed

    Egerton, Terry A; Everall, Neil J; Tooley, Ian R

    2005-03-29

    This paper uses measurements of adsorption and vibrational spectra (DRIFTS, ATR, and Raman) to characterize TiO2 (rutile) nanoparticles that have been surface treated with aluminum and stearate, "aluminum stearate". From these measurements, we have developed a model of titania particles covered by patches of "alumina". Vibrational spectra, particularly the spectra of the carboxylate headgroups, show that the stearate then adsorbs on both the titania and the alumina. Surprisingly, the distribution of the stearate between alumina and titania is sensitive to the presence of water. As the water content decreases, the relative amounts of stearate on titania, rather than alumina, increase, and this increase is accompanied by a less ordered structuring of the stearate tails, as evidenced by a shift of the C-H stretching bands to higher frequencies and a broadening of the 1296 cm(-1) Raman band. This effect is consistent with earlier observations that the presence of water reduced the bonding of stearate headgroups to the surface of titania. We have also shown that the dispersion in C12-C15 alkyl benzoate of aluminum stearate coated titania is sensitive to the presence of small amounts, approximately 4%, of water. Finally, we have demonstrated that surface stearate, like surface alumina, reduces the rate of phototocatalytic oxidation of 2-propanol. A 7% stearate coating reduces acetone formation by a factor of 4. There is no evidence from these studies that, during the oxidation experiment, 2-propanol displaces stearate from the titania surface.

  14. Glycyrrhetinic acid alleviates radiation-induced lung injury in mice

    PubMed Central

    Chen, Jinmei; Zhang, Weijian; Zhang, Lurong; Zhang, Jiemin; Chen, Xiuying; Yang, Meichun; Chen, Ting; Hong, Jinsheng

    2017-01-01

    Radiation-induced lung injury (RILI) is a common complication of thoracic radiotherapy, but efficacious therapy for RILI is lacking. This study ascertained whether glycyrrhetinic acid (GA; a functional hydrolyzed product of glycyrrhizic acid, which is extracted from herb licorice) can protect against RILI and investigated its relationship to the transforming growth factor (TGF)-β1/Smads signaling pathway. C57BL/6 mice were divided into four groups: a control group, a GA group and two irradiation (IR) groups. IR groups were exposed to a single fraction of X-rays (12 Gy) to the thorax and administered normal saline (IR + NS group) or GA (IR + GA group). Two days and 17 days after irradiation, histologic analyses were performed to assess the degree of lung injury, and the expression of TGF-β1, Smad2, Smad3 and Smad7 was recorded. GA administration mitigated the histologic changes of lung injury 2 days and 17 days after irradiation. Protein and mRNA expression of TGF-β1, Smad2 and Smad3, and the mRNA level of Smad7, in lung tissue were significantly elevated after irradiation. GA decreased expression of TGF-β1, Smad2 and Smad3 in lung tissue, but did not increase Smad7 expression. GA can protect against early-stage RILI. This protective effect may be associated with inhibition of the TGF-β1/Smads signaling pathway. PMID:27672101

  15. Glycyrrhetinic Acid Mediated Drug Delivery Carriers for Hepatocellular Carcinoma Therapy.

    PubMed

    Cai, Yuee; Xu, Yingqi; Chan, Hon Fai; Fang, Xiaobin; He, Chengwei; Chen, Meiwan

    2016-03-07

    Glycyrrhetinic acid (GA), the main hydrolysate of glycyrrhizic acid extracted from the root of licorice, has been used in hepatocellular carcinoma (HCC) therapy. Particularly, GA as a ligand in HCC therapy has been widely explored in different drug delivery systems, including liposomes, micelles, and nanoparticles. There is considerable interest worldwide with respect to the development of GA-modified drug delivery systems due to the extensive presence of GA receptors on the surface of hepatocyte. Up until now, much work has been focused on developing GA-modified drug delivery systems which bear good liver- or hepatocyte-targeted efficiency both in vitro and in vivo. Owing to its contribution in overcoming the limitations of low lipophilicity and poor bioavailability as well as its ability to promote receptor-mediated endocytosis, GA-modified drug delivery systems play an important role in enhancing liver-targeting efficacy and thus are focused on the treatment of HCC. Moreover, since GA-modified delivery systems present more favorable pharmacokinetic properties and hepatocyte-targeting effects, they may be a promising formulation for GA in the treatment of HCC. In this review, we will give an overview of GA-modified novel drug delivery systems, paying attention to their efficacy in treating HCC and discussing their mechanism and the treatment effects.

  16. Interaction of glycyrrhizin and glycyrrhetinic acid with DNA.

    PubMed

    Nafisi, Shohreh; Bonsaii, Mahyar; Manouchehri, Firouzeh; Abdi, Khosrou

    2012-01-01

    Glycyrrhizin (GL), a molecule of glycyrrhetinic acid (GA), is an aqueous extract from licorice root. These compounds are well known for their anti-inflammatory, hepatocarcinogenesis, antiviral, and interferon-inducing activities. This study is the first attempt to investigate the binding of GL and GA with DNA. The effect of ligand complexation on DNA aggregation and condensation was investigated in aqueous solution at physiological conditions, using constant DNA concentration (6.25 mM) and various ligands/polynucleotide (phosphate) ratios of 1/240, 1/120, 1/80, 1/40, 1/20, 1/10, 1/5, 1/2, and 1/1. Fourier transform infrared and ultraviolet (UV)-visible spectroscopic methods were used to determine the ligand binding modes, the binding constants, and the stability of ligand-DNA complexes in aqueous solution. Spectroscopic evidence showed that GL and GA bind DNA via major and minor grooves as well as the backbone phosphate group with overall binding constants of K(GL-DNA)=5.7×10(3) M(-1), K(GA-DNA)=5.1×10(3) M(-1). The affinity of ligand-DNA binding is in the order of GL>GA. DNA remained in the B-family structure, whereas biopolymer aggregation occurred at high triterpenoid concentrations.

  17. Structural properties of magnesium stearate pseudopolymorphs: effect of temperature.

    PubMed

    Bracconi, Pierre; Andrès, Cyrille; Ndiaye, Augustin

    2003-08-27

    A thorough review of the relevant literature reveals that the interaction between water vapour and magnesium stearate, in contrast to many other metal soaps, is not properly understood. The structural modifications associated with the up-take or loss of water of vegetable-derived commercial magnesium stearate powders exposed to humid air or vacuum at room temperature are investigated using standard powder X-ray diffractometry. It is found that in such conditions magnesium stearate reacts reversibly with the vapour phase with structural consequences very similar to the high temperature transition between the crystalline and rotator phases of other anhydrous metal soaps. When temperature is increased under dry nitrogen the diffraction band characteristic of the rotator phase shifts towards higher angle values and the corresponding lattice spacing increases at the rate of 6.9x10(-4)C(-1). Melting takes place gradually above 100 degrees C as revealed by the collapse of the diffraction band and the growth of the broader diffusion band characteristic of the liquid state. Full clarification of the structure of the hydrated and dried phases proves impossible based on powder diffraction spectra obtained with conventional high resolution X-ray diffraction equipment.

  18. The mechanism of hydrothermal hydrolysis for glycyrrhizic acid into glycyrrhetinic acid and glycyrrhetinic acid 3-O-mono-β-D-glucuronide in subcritical water.

    PubMed

    Fan, Rui; Li, Nan; Xu, Honggao; Xiang, Jun; Wang, Lei; Gao, Yanxiang

    2016-01-01

    To improve the bioactivity and sweetness properties of glycyrrhizic acid (GL), the hydrothermal hydrolysis of GL into glycyrrhetinic acid (GA) and glycyrrhetinic acid 3-O-mono-β-D-glucuronide (GAMG) in subcritical water was investigated. The effects of temperature, time and their interaction on the conversion ratios were analyzed and the reactions were elaborated with kinetics and thermodynamics. The results showed that GL hydrothermal hydrolysis was significantly (P < 0.05) affected by reaction time and temperature, as well as their interaction, and could be fitted into first-order kinetics. The thermodynamic analysis indicated that the hydrolysis of GL was endergonic and non-spontaneous. The hydrolytic pathways were composed of complex consecutive and parallel reactions. It was concluded that subcritical water may be a potential medium for producing GAMG and GA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Binding effect of fluorescence labeled glycyrrhetinic acid with GA receptors in hepatocellular carcinoma cells.

    PubMed

    Sun, Yu-Qi; Dai, Chun-Mei; Zheng, Yan; Shi, Shu-Dan; Hu, Hai-Yang; Chen, Da-Wei

    2017-11-01

    Glycyrrhetinic acid (GA) is a natural active component from licorice, which is broadly used in traditional Chinese medicine. Lots of glycyrrhetinic acid receptors (GA-R) are proved to locate on the surface of liver cells. Many reports about the hepatocellular carcinoma (HCC) treatment were dependent on GA modified carriers. However, the reality of GA-R in HCC cells was not clear. In this paper, 18β-glycyrrhetinic acid (18β-GA) was labeled with fluorescence (FITC) by chemical synthesis. Together with the binding effect of fluorescence labeled glycyrrhetinic acid (FITC-GA), the competitive action of 18β-GA with GA-R was investigated in HCC cells. The results showed that in HepG2 cells, 18β-GA and FITC-GA presented similar cytotoxicity. The specific binding saturation of GA showed the dissociation constant (Kd) was 7.457±2.122pmol/L and the maximum binding counts (Bmax) was 2.385±0.175pmol/2.5×10(6) cells, respectively. FITC-GA bound to cytomembrane specifically and 18β-GA competed to bind the sites significantly in HepG2 cells. Therefore, there is binding effect between fluorescence labeled GA and GA-R. The GA-R on HCC cells is confirmed as expected, which provides a useful reference of active target modified by GA and a novel approach for receptors and ligands study. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Modulation by glycyrrhetinic acid derivatives of TPA-induced mouse ear oedema.

    PubMed Central

    Inoue, H.; Mori, T.; Shibata, S.; Koshihara, Y.

    1989-01-01

    1. The anti-inflammatory effects of glycyrrhetinic acid and its derivatives on TPA (12-O-tetradecanoylphorbol-13-acetate)-induced mouse ear oedema were studied. The mechanisms of TPA-induced ear oedema were first investigated with respect to the chemical mediators. 2. The formation of ear oedema reached a maximum 5 h after TPA application (2 micrograms per ear) and the prostaglandin E2 (PGE2) production of mouse ear increased with the oedema formation. 3. TPA-induced ear oedema was prevented by actinomycin D and cycloheximide (0.1 mg per ear, respectively) when applied during 60 min after TPA treatment. 4. Of glycyrrhetinic acid derivatives examined, dihemiphthalate derivatives (IIe, IIe', IIIa, IIIa', IVa, IVa') most strongly inhibited ear oedema on both topical (ID50, 1.6 mg per ear for IIe, 2.0 mg per ear for IIIa and 1.6 mg per ear for IVa) and oral (ID50, 88 mg kg-1 for IIe', 130 mg kg-1 for IIIa' and 92 mg kg-1 for IVa') administration. 5. Glycyrrhetinic acid (Ia) and its derivatives applied 30 min before TPA treatment were much more effective in inhibiting oedema than when applied 30 min after TPA. A dihemiphthalate of triterpenoid compound IVa completely inhibited oedema, even when applied 3 h before TPA treatment. 6. Glycyrrhetinic acid (Ia) and deoxoglycyrrhetol (IIa), the parent compounds, produced little inhibition by oral administration at less than 200 mg kg-1. 7. These results suggest that the dihemiphthalate derivatives of triterpenes derived from glycyrrhetinic acid by chemical modification are useful for the treatment of skin inflammation by both topical and oral application. PMID:2924072

  1. 21 CFR 178.3505 - Glyceryl tri-(12-acetoxy-stearate).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glyceryl tri-(12-acetoxy-stearate). 178.3505... SANITIZERS Certain Adjuvants and Production Aids § 178.3505 Glyceryl tri-(12-acetoxy-stearate). Glyceryl tri... calcium carbonate/glyceryl tri-(12-acetoxystearate) mixture is used as an adjuvant in polymers in contact...

  2. Extruded foams prepared from high amylose starch with sodium stearate to form amylose inclusion complexes

    USDA-ARS?s Scientific Manuscript database

    Starch foams were prepared from high amylose corn starch in the presence and absence of sodium stearate and PVOH to determine how the formation of amylose-sodium stearate inclusion complexes and the addition of PVOH would affect foam properties. Low extrusion temperatures were used, and X-ray diffra...

  3. An Aluminum Magnesium Hydroxide Stearate-based Skin Barrier Protection Cream Used for the Management of Eczematous Dermatitis

    PubMed Central

    Bhambri, Sanjay; Michaels, Brent

    2008-01-01

    Eczematous dermatoses can often be very difficult to treat. An aluminum magnesium hydroxide stearate-based cream has recently become available for clinical use. Aluminum magnesium hydroxide stearate-based cream provides an alternative option in treating these dermatoses while providing barrier protection against external allergens and irritants. This article reviews various studies evaluating aluminum magnesium hydroxide stearate-based cream. PMID:21212843

  4. Synthesis and pro-apoptotic activity of novel glycyrrhetinic acid derivatives.

    PubMed

    Logashenko, Evgeniya B; Salomatina, Oksana V; Markov, A V; Korchagina, Dina V; Salakhutdinov, Nariman F; Tolstikov, Genrikh A; Vlassov, Valentin V; Zenkova, Marina A

    2011-03-21

    Triterpenoids are used for medicinal purposes in many countries. Some, such as oleanolic and glycyrrhetinic acids, are known to be anti-inflammatory and anticarcinogenic. However, the biological activities of these naturally occurring molecules against their particular targets are weak, so the synthesis of new synthetic analogues with enhanced potency is needed. By combining modifications to both the A and C rings of 18βH-glycyrrhetinic acid, the novel synthetic derivative methyl 2-cyano-3,12-dioxo-18βH-olean-9(11),1(2)-dien-30-oate was obtained. This derivative displays high antiproliferative activity in cancer cells, including a cell line with a multidrug-resistance phenotype. It causes cell death by inducing the intrinsic caspase-dependent apoptotic pathway. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Synthesis and Pro-Apoptotic Activity of Novel Glycyrrhetinic Acid Derivatives

    PubMed Central

    Logashenko, Evgeniya B; Salomatina, Oksana V; Markov, A V; Korchagina, Dina V; Salakhutdinov, Nariman F; Tolstikov, Genrikh A; Vlassov, Valentin V; Zenkova, Marina A

    2011-01-01

    Triterpenoids are used for medicinal purposes in many countries. Some, such as oleanolic and glycyrrhetinic acids, are known to be anti-inflammatory and anticarcinogenic. However, the biological activities of these naturally occurring molecules against their particular targets are weak, so the synthesis of new synthetic analogues with enhanced potency is needed. By combining modifications to both the A and C rings of 18βH-glycyrrhetinic acid, the novel synthetic derivative methyl 2-cyano-3,12-dioxo-18βH-olean-9(11),1(2)-dien-30-oate was obtained. This derivative displays high antiproliferative activity in cancer cells, including a cell line with a multidrug-resistance phenotype. It causes cell death by inducing the intrinsic caspase-dependent apoptotic pathway. PMID:21328513

  6. Degradability Enhancement of Poly(Lactic Acid) by Stearate-Zn3Al LDH Nanolayers

    PubMed Central

    Eili, Mahboobeh; Shameli, Kamyar; Ibrahim, Nor Azowa; Yunus, Wan Md Zin Wan

    2012-01-01

    Recent environmental problems and societal concerns associated with the disposal of petroleum based plastics throughout the world have triggered renewed efforts to develop new biodegradable products compatible with our environment. This article describes the preparation, characterization and biodegradation study of poly(lactic acid)/layered double hydroxide (PLA/LDH) nanocomposites from PLA and stearate-Zn3Al LDH. A solution casting method was used to prepare PLA/stearate-Zn3Al LDH nanocomposites. The anionic clay Zn3Al LDH was firstly prepared by co-precipitation method from a nitrate salt solution at pH 7.0 and then modified by stearate anions through an ion exchange reaction. This modification increased the basal spacing of the synthetic clay from 8.83 Å to 40.10 Å. The morphology and properties of the prepared PLA/stearate-Zn3Al LDH nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), tensile tests as well as biodegradation studies. From the XRD analysis and TEM observation, the stearate-Zn3Al LDH lost its ordered stacking-structure and was greatly exfoliated in the PLA matrix. Tensile test results of PLA/stearate-Zn3Al LDH nanocomposites showed that the presence of around 1.0–3.0 wt % of the stearate-Zn3Al LDH in the PLA drastically improved its elongation at break. The biodegradation studies demonstrated a significant biodegradation rate improvement of PLA in the presence of stearate-Zn3Al LDH nanolayers. This effect can be caused by the catalytic role of the stearate groups in the biodegradation mechanism leading to much faster disintegration of nanocomposites than pure PLA. PMID:22942682

  7. Degradability enhancement of poly(lactic acid) by stearate-Zn(3)Al LDH nanolayers.

    PubMed

    Eili, Mahboobeh; Shameli, Kamyar; Ibrahim, Nor Azowa; Yunus, Wan Md Zin Wan

    2012-01-01

    Recent environmental problems and societal concerns associated with the disposal of petroleum based plastics throughout the world have triggered renewed efforts to develop new biodegradable products compatible with our environment. This article describes the preparation, characterization and biodegradation study of poly(lactic acid)/layered double hydroxide (PLA/LDH) nanocomposites from PLA and stearate-Zn(3)Al LDH. A solution casting method was used to prepare PLA/stearate-Zn(3)Al LDH nanocomposites. The anionic clay Zn(3)Al LDH was firstly prepared by co-precipitation method from a nitrate salt solution at pH 7.0 and then modified by stearate anions through an ion exchange reaction. This modification increased the basal spacing of the synthetic clay from 8.83 Å to 40.10 Å. The morphology and properties of the prepared PLA/stearate-Zn(3)Al LDH nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), tensile tests as well as biodegradation studies. From the XRD analysis and TEM observation, the stearate-Zn(3)Al LDH lost its ordered stacking-structure and was greatly exfoliated in the PLA matrix. Tensile test results of PLA/stearate-Zn(3)Al LDH nanocomposites showed that the presence of around 1.0-3.0 wt % of the stearate-Zn(3)Al LDH in the PLA drastically improved its elongation at break. The biodegradation studies demonstrated a significant biodegradation rate improvement of PLA in the presence of stearate-Zn(3)Al LDH nanolayers. This effect can be caused by the catalytic role of the stearate groups in the biodegradation mechanism leading to much faster disintegration of nanocomposites than pure PLA.

  8. Interaction of tablet disintegrants and magnesium stearate during mixing I: Effect on tablet disintegration.

    PubMed

    Bolhuis, G K; Smallenbroek, A J; Lerk, C F

    1981-12-01

    The effect of magnesium stearate on the disintegration of tablets was studied. Three different preblends, containing a slightly or a strongly swelling disintegrant, were mixed before compression with magnesium stearate for different time periods. The results show that a strongly swelling disintegrant, such as sodium starch glycolate in contrast to potato starch, can reduce the deteriorating effect of hydrophobic lubricants on tablet disintegration. However, the interaction between magnesium stearate and potato starch or sodium starch glycolate and the resulting differences in disintegration characteristics can be masked by the use of disks in the USP disintegration apparatus.

  9. The protection of glycyrrhetinic acid (GA) towards acetaminophen (APAP)-induced toxicity partially through fatty acids metabolic pathway.

    PubMed

    Yang, Hua; Jiang, Tingshu; Li, Ping; Mao, Qishan

    2015-09-01

    Acetaminophen (APAP)-induced liver toxicity remains the key factor limiting the clinical application of APAP, and herbs are the important sources for isolation of compounds preventing APAP-induced toxicity. To investigate the protection mechanism of glycyrrhetinic acid towards APAP-induced liver damage using metabolomics method. APAP-induced liver toxicity model was made through intraperitoneal injection (i.p.) of APAP (400 mg/kg). Glycyrrhetinic acid was dissolved in corn oil, and intraperitoneal injection (i.p.) of glycyrrhetinic acid (500 mg/kg body weight) was performed for 20 days before the injection of APAP. UPLC-ESI-QTOF MS was employed to analyze the metabolomic profile of serum samples. The pre-treatment of glycyrrhetinic acid significantly protected APAP-induced toxicity, indicated by the histology of liver, the activity of ALT and AST. Metabolomics showed that the level of palmtioylcarnitine and oleoylcarnitine significantly increased in serum of APAP-treated mice, and the pre-treatment with GA can prevent this elevation of these two fatty acid-carnitines. Reversing the metabolism pathway of fatty acid is an important mechanism for the protection of glycyrrhetinic acid towards acetaminophen-induced liver toxicity.

  10. Glycyrrhetinic acid exhibits strong inhibitory effects towards UDP-glucuronosyltransferase (UGT) 1A3 and 2B7.

    PubMed

    Huang, Yin-Peng; Cao, Yun-Feng; Fang, Zhong-Ze; Zhang, Yan-Yan; Hu, Cui-Min; Sun, Xiao-Yu; Yu, Zhen-Wen; Zhu, Xu; Hong, Mo; Yang, Lu; Sun, Hong-Zhi

    2013-09-01

    The aim of the present study is to evaluate the inhibitory effects of liver UDP-glucuronosyltransferases (UGTs) by glycyrrhizic acid and glycyrrhetinic acid, which are the bioactive ingredients isolated from licorice. The results showed that glycyrrhetinic acid exhibited stronger inhibition towards all the tested UGT isoforms, indicating that the deglycosylation process played an important role in the inhibitory potential towards UGT isoforms. Furthermore, the inhibition kinetic type and parameters were determined for the inhibition of glycyrrhetinic acid towards UGT1A3 and UGT2B7. Data fitting using Dixon and Lineweaver-Burk plots demonstrated that the inhibition of UGT1A3 and UGT2B7 by glycyrrhetinic acid was best fit to competitive and noncompetitive type, respectively. The second plot using the slopes from Lineweaver-Burk plots versus glycyrrhetinic acid concentrations was employed to calculate the inhibition kinetic parameters (K(i)), and the values were calculated to be 0.2 and 1.7 μM for UGT1A3 and UGT2B7, respectively. All these results remind us the possibility of UGT inhibition-based herb-drug interaction. However, the explanation of these in vitro parameters should be paid more caution due to complicated factors, including the probe substrate-dependent UGT inhibition behaviour, environmental factors affecting the abundance of herbs' ingredients, and individual difference of pharmacokinetic factors.

  11. Extraction of stearate salts from plastic materials used in pharmaceutical applications.

    PubMed

    Jenke, Dennis

    2010-01-01

    Plastic materials are widely used in medical items such as solution containers, infusion sets, transfer tubing, devices, processing equipment and systems, filters, and the like. Components in medical items can leach out of such items when they are contacted by a therapeutic product or product-related solution. Stearic acid and stearate salts are commonly present in medical and food packaging, either as plastic additives, processing aids, or contaminants, and their leaching from plastics is well documented. With a pK(a) in the range of 5.1 to 5.6 and limited aqueous solubility (log P(o/w) greater than 8), the leaching of stearic acid (and its related metal salts) into pharmaceutical products is expected to be strongly dependent on the product's pH and polarity. In order to establish and understand the leaching behavior of stearate-containing materials, three compounds (stearic acid, calcium stearate, and zinc stearate) and four polymeric materials containing these compounds were contacted with aqueous buffers in the pH range of 2.5 to 11. The leached levels of calcium, zinc, stearate, palmitate, and total organic carbon (TOC) were measured in the resulting solutions and are reported. For materials containing only stearic acid or salts themselves, the extraction of these entities is pH-dependent. At low pH, the cation counter-ions of the stearate salts are extracted from the plastic materials by a process that can loosely be termed ion exchange. At intermediate pH, little or no extraction of the stearates occurs. At high pH, the stearates are extracted from the materials to a very limited extent due to the solubility of the acid and/or salts in the extraction medium.

  12. Non-debye dielectric response in monolithic layers of silver stearate

    NASA Astrophysics Data System (ADS)

    Kastro, R. A.; Goryaev, M. A.; Smirnov, A. P.

    2017-02-01

    This paper reports on the results of investigations of the electrophysical properties of silver stearate by the methods of dielectric spectroscopy and differential scanning calorimetry (DSC). The mechanisms of charge transfer and dielectric relaxation in silver stearate have been established. It has been found that there is a critical temperature T = 338 K, which is probably related to the low-temperature phase transition in the system under investigation.

  13. Production of calcium-stearate by lipase using hydrogenated beef tallow.

    PubMed

    Lee, Hyang-Bok; Kwon, Jin-Soo; Kim, Young-Bum; Kim, Eun-Ki

    2009-05-01

    Calcium-stearate has been traditionally produced by chemical methods, producing wastes and requiring high energy because of high temperature operation. To achieve enzymatic production of calcium-stearate at unfavorable conditions, i.e., pH 10 and 60 degrees C, suitable lipase was selected and reaction conditions were optimized using calcium hydroxide and hydrogenated beef tallow as substrates. Under optimum conditions, 95% of beef tallow, in 2.5 h, was converted into calcium-stearate by using commercial lipase SDL 451. Investigation of the time-course reaction revealed that fatty acid was initially produced by lipase, followed by conversion into calcium-stearate. The fatty acid production rate was faster than that of the conversion into calcium-stearate at the beginning of the reaction. Alkaline pH, originating from the addition of calcium hydroxide, increased the converting reaction. This is the first report demonstrating that chemical production of calcium-stearate can be replaced by enzymatic reaction, thereby creating a cleaner process.

  14. Challenges in detecting magnesium stearate distribution in tablets.

    PubMed

    Lakio, Satu; Vajna, Balázs; Farkas, István; Salokangas, Henri; Marosi, György; Yliruusi, Jouko

    2013-03-01

    Magnesium stearate (MS) is the most commonly used lubricant in pharmaceutical industry. During blending, MS particles form a thin layer on the surfaces of the excipient and drug particles prohibiting the bonding from forming between the particles. This hydrophobic layer decreases the tensile strength of tablets and prevents water from penetrating into the tablet restraining the disintegration and dissolution of the tablets. Although overlubrication of the powder mass during MS blending is a well-known problem, the lubricant distribution in tablets has traditionally been challenging to measure. There is currently no adequate analytical method to investigate this phenomenon. In this study, the distribution of MS in microcrystalline cellulose (MCC) tablets was investigated using three different blending scales. The crushing strength of the tablets was used as a secondary response, as its decrease is known to result from the overlubrication. In addition, coating of the MCC particles by MS in intact tablets was detected using Raman microscopic mapping. MS blending was more efficient in larger scales. Raman imaging was successfully applied to characterize MS distribution in MCC tablets despite low concentration of MS. The Raman method can provide highly valuable visual information about the proceeding of the MS blending process. However, the measuring set-up has to be carefully planned to establish reliable and reproducible results.

  15. Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

    NASA Astrophysics Data System (ADS)

    Aras, Neny Rasnyanti M.; Arcana, I. Made

    2015-09-01

    An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm-1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese stearate

  16. Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

    SciTech Connect

    Aras, Neny Rasnyanti M. Arcana, I Made

    2015-09-30

    An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm{sup −1} which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese

  17. Inverted polymer solar cells with enhanced fill factor by inserting the potassium stearate interfacial modification layer

    SciTech Connect

    Li, Jiangsheng; Jiu, Tonggang E-mail: fangjf@nimte.ac.cn; Li, Bairu; Kuang, Chaoyang; Chen, Qiushan; Ma, Sushuang; Fang, Junfeng E-mail: fangjf@nimte.ac.cn; Shu, Jie

    2016-05-02

    A thin potassium stearate (KSt) film combined with an optimized ZnO film was introduced to improve the fill factor (FF) of highly efficient inverted polymer solar cells (PSCs). Atomic force microscopy and contact angle measurements were used to show that the introduction of KSt did not change the morphology of interlayer. On the contrary, it is beneficial for the spread of the active layer on the interlayer. The origin of enhanced FF was systematically studied by the ideal current-voltage model for a single heterojunction solar cell and electrochemical impedance spectroscopy. On the basis of the data analysis, the reduced charge recombination loss was responsible for this improved FF. At last, when KSt was replaced by sodium stearate (NaSt), the similar experiment phenomenon was observed. This indicates that inserting a metallic stearate modified layer is a promising strategy to enhance inverted PSCs performance.

  18. Detailed Chemical Kinetic Reaction Mechanism for Biodiesel Components Methyl Stearate and Methyl Oleate

    SciTech Connect

    Naik, C; Westbrook, C K; Herbinet, O; Pitz, W J; Mehl, M

    2010-01-22

    New chemical kinetic reaction mechanisms are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate. The mechanisms are produced using existing reaction classes and rules for reaction rates, with additional reaction classes to describe other reactions unique to methyl ester species. Mechanism capabilities were examined by computing fuel/air autoignition delay times and comparing the results with more conventional hydrocarbon fuels for which experimental results are available. Additional comparisons were carried out with measured results taken from jet-stirred reactor experiments for rapeseed methyl ester fuels. In both sets of computational tests, methyl oleate was found to be slightly less reactive than methyl stearate, and an explanation of this observation is made showing that the double bond in methyl oleate inhibits certain low temperature chain branching reaction pathways important in methyl stearate. The resulting detailed chemical kinetic reaction mechanism includes more approximately 3500 chemical species and more than 17,000 chemical reactions.

  19. Lipases efficiently stearate and cutinases acetylate the surface of arabinoxylan films.

    PubMed

    Stepan, A M; Anasontzis, G E; Matama, T; Cavaco-Paulo, A; Olsson, L; Gatenholm, P

    2013-08-10

    This is the first report on successful enzyme catalyzed surface esterification of hemicellulose films. Enzyme catalyzed surface acetylation with vinyl acetate and stearation with vinyl stearate were studied on rye arabinoxylan (AX) films. Different surface analytical techniques (FT-IR, TOF-SIMS, ESCA, CA) show that lipases from Mucor javanicus, Rhizopus oryzae and Candida rugosa successfully surface stearate AX films and that a cutinase from Fusarium solani pisi surface acetylates these films. The specificities of cutinase and lipases were also compared, and higher activity was observed for lipases utilizing long alkyl chain substrates while higher activity was observed for cutinase utilizing shorter alkyl chain substrates. The contact angle analysis showed films with increased initial hydrophobicity on the surfaces. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Inverted polymer solar cells with enhanced fill factor by inserting the potassium stearate interfacial modification layer

    NASA Astrophysics Data System (ADS)

    Li, Jiangsheng; Jiu, Tonggang; Li, Bairu; Kuang, Chaoyang; Chen, Qiushan; Ma, Sushuang; Shu, Jie; Fang, Junfeng

    2016-05-01

    A thin potassium stearate (KSt) film combined with an optimized ZnO film was introduced to improve the fill factor (FF) of highly efficient inverted polymer solar cells (PSCs). Atomic force microscopy and contact angle measurements were used to show that the introduction of KSt did not change the morphology of interlayer. On the contrary, it is beneficial for the spread of the active layer on the interlayer. The origin of enhanced FF was systematically studied by the ideal current-voltage model for a single heterojunction solar cell and electrochemical impedance spectroscopy. On the basis of the data analysis, the reduced charge recombination loss was responsible for this improved FF. At last, when KSt was replaced by sodium stearate (NaSt), the similar experiment phenomenon was observed. This indicates that inserting a metallic stearate modified layer is a promising strategy to enhance inverted PSCs performance.

  1. High levels of dietary stearate promote adiposity and deteriorate hepatic insulin sensitivity

    PubMed Central

    2010-01-01

    Background Relatively little is known about the role of specific saturated fatty acids in the development of high fat diet induced obesity and insulin resistance. Here, we have studied the effect of stearate in high fat diets (45% energy as fat) on whole body energy metabolism and tissue specific insulin sensitivity. Methods C57Bl/6 mice were fed a low stearate diet based on palm oil or one of two stearate rich diets, one diet based on lard and one diet based on palm oil supplemented with tristearin (to the stearate level of the lard based diet), for a period of 5 weeks. Ad libitum fed Oxidative metabolism was assessed by indirect calorimetry at week 5. Changes in body mass and composition was assessed by DEXA scan analysis. Tissue specific insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp analysis and Western blot at the end of week 5. Results Indirect calorimetry analysis revealed that high levels of dietary stearate resulted in lower caloric energy expenditure characterized by lower oxidation of fatty acids. In agreement with this metabolic phenotype, mice on the stearate rich diets gained more adipose tissue mass. Whole body and tissue specific insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp and analysis of insulin induced PKBser473 phosphorylation. Whole body insulin sensitivity was decreased by all high fat diets. However, while insulin-stimulated glucose uptake by peripheral tissues was impaired by all high fat diets, hepatic insulin sensitivity was affected only by the stearate rich diets. This tissue-specific pattern of reduced insulin sensitivity was confirmed by similar impairment in insulin-induced phosphorylation of PKBser473 in both liver and skeletal muscle. Conclusion In C57Bl/6 mice, 5 weeks of a high fat diet rich in stearate induces a metabolic state favoring low oxidative metabolism, increased adiposity and whole body insulin resistance characterized by severe hepatic insulin resistance. These results

  2. Selective inhibition of 11beta-hydroxysteroid dehydrogenase 1 by 18alpha-glycyrrhetinic acid but not 18beta-glycyrrhetinic acid.

    PubMed

    Classen-Houben, Dirk; Schuster, Daniela; Da Cunha, Thierry; Odermatt, Alex; Wolber, Gerhard; Jordis, Ulrich; Kueenburg, Bernhard

    2009-02-01

    Elevated cortisol concentrations have been associated with metabolic diseases such as diabetes type 2 and obesity. 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 1, catalyzing the conversion of inactive 11-ketoglucocorticoids into their active 11beta-hydroxy forms, plays an important role in the regulation of cortisol levels within specific tissues. The selective inhibition of 11beta-HSD1 is currently considered as promising therapeutic strategy for the treatment of metabolic diseases. In recent years, natural compound-derived drug design has gained considerable interest. 18beta-glycyrrhetinic acid (GA), a metabolite of the natural product glycyrrhizin, is not selective and inhibits both 11beta-HSD1 and 11beta-HSD2. Here, we compare the biological activity of 18beta-GA and its diastereomer 18alpha-GA against the two enzymes in lysates of transfected HEK-293 cells and show that 18alpha-GA selectively inhibits 11beta-HSD1 but not 11beta-HSD2. This is in contrast to 18beta-GA, which preferentially inhibits 11beta-HSD2. Using a pharmacophore model based on the crystal structure of the GA-derivative carbenoxolone in complex with human 11beta-HSD1, we provide an explanation for the differences in the activities of 18alpha-GA and 18beta-GA. This model will be used to design novel selective derivatives of GA.

  3. An Aluminum Magnesium Hydroxide Stearate-based Skin Barrier Protection Cream Used for the Management of Eczematous Dermatitis: A Summary of Completed Studies.

    PubMed

    Del Rosso, James Q; Bhambri, Sanjay; Michaels, Brent

    2008-11-01

    Eczematous dermatoses can often be very difficult to treat. An aluminum magnesium hydroxide stearate-based cream has recently become available for clinical use. Aluminum magnesium hydroxide stearate-based cream provides an alternative option in treating these dermatoses while providing barrier protection against external allergens and irritants. This article reviews various studies evaluating aluminum magnesium hydroxide stearate-based cream.

  4. Antitumor Agents 255. Novel Glycyrrhetinic Acid-Dehydrozingerone Conjugates as Cytotoxic Agents

    PubMed Central

    Tatsuzaki, Jin; Taniguchi, Masahiko; Bastow, Kenneth F.; Nakagawa-Goto, Kyoko; Morris-Natschke, Susan L.; Itokawa, Hideji; Baba, Kimiye; Lee, Kuo-Hsiung

    2007-01-01

    Esterification of glycyrrhetinic acid (GA) with dehydrozingerone (DZ) resulted in a novel cytotoxic GA-DZ conjugate. Based on this exciting finding, we conjugated eleven different DZ analogs with GA or other triterpenoids, including oleanoic acid (OA) or ursolic acid (UA). In an in vitro anticancer assay using nine different human tumor cell lines, most of the GA-DZ conjugates showed significant potency. Particularly, compounds 5, 29, and 30 showed significant cytotoxic effects against LN-Cap, 1A9, and KB cells with ED50 values of 0.6, 0.8, and 0.9 μM, respectively. Similar conjugates between DZ and OA or UA were inactive suggesting that the GA component is critical for activity. Notably, although GA-DZ conjugates showed potent cytotoxic activity, the individual components (GA and DZ analogs) were inactive. Thus, GA-DZ conjugates are new chemical entities and represent interesting hits for anticancer drug discovery and development. PMID:17591444

  5. Impact of solid-state properties on lubrication efficacy of magnesium stearate.

    PubMed

    Rao, K Phanidhara; Chawla, Garima; Kaushal, Aditya M; Bansal, Arvind K

    2005-01-01

    The advent of high-speed tableting and slug capsule-filling machines has ushered in an increasingly important role for the lubricants to enact during manufacturing of dosage forms. Although lubricants help in processing, they can also adversely affect the flow properties and dissolution profile of the drug. It is thus critical to maintain a balance between these two behaviors, by understanding the underlying mechanisms and using their optimum concentration in the formulation. The source and manufacturing process inculcate different solid-state properties to magnesium stearate, the most commonly used lubricant, leading to variations in its lubrication efficacy. However, there has been no complete study relating the lubrication efficacy of magnesium stearate to various levels of solid state. Hence, this study was aimed at comprehensively scrutinizing the role of molecular, particle, and bulk level properties of solid state on the lubrication efficacy of magnesium stearate. A method based on net work done during compression using texture analyzer, was developed and validated to analyze its performance. Particle and bulk-level properties were studied using microscopy, particle size analysis, and particle surface area determination, and molecular level was characterized using thermal, spectroscopic, and crystallographic methods. Interplay of solid-state characteristics such as particle size, degree of agglomeration, and crystal habit were found to markedly influence the lubrication potential of magnesium stearate.

  6. Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

    SciTech Connect

    Asriza, Ristika O.; Arcana, I Made

    2015-09-30

    Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

  7. Solvent-free acid-catalyzed ring-opening of epoxidized oleochemicals using stearates/stearic acid, and its applications.

    PubMed

    Ahn, Byung-Jun Kollbe; Kraft, Stefan; Sun, Xiuzhi Susan

    2012-03-07

    Toxic solvent and strong acid catalysts causing environmental issues have been mainly used for ring-opening of epoxidized oleochemicals. Here, we demonstrated that magnesium stearate (Mg-stearate) was a high efficient catalyst for solvent-free ring-opening of epoxidized methyl oleate, a model compound of midchain epoxide. Mg-stearate resulted in the highest yield (95%) and conversion rate (99%) toward midchain alkoxyesters under the same conditions (160 °C, 12 h) superior to other fatty acid derivatives such as a Lewis acid (lithium and sodium stearate) and Brønsted acid (stearic acid). Based on this chemical study, we synthesized biogrease and thermoplastic using epoxidized soybean oil (ESO) and Mg-stearate via one-pot, solvent-free, and purification-free process. Mg-stearate played a significant role as a reactant for epoxide ring-opening and as a thickener when excess loading rate was used; viscosity increased from 1800 to 4500 Pa·s at 25 °C when ESO:Mg-stearate increased from 1:1 equiv to 1:2, then behaved like thermoplastics (T(g) = -27 °C, T(m) = 90 °C) with 1:4.

  8. Release of albumin from oligoester plastic matrices: effect of magnesium oxide and bivalent stearates.

    PubMed

    Kladnícková, I; Dittrich, M; Klein, T; Pokorová, D

    2006-01-01

    Biodegradable implantable matrices containing bovine serum albumin were prepared from oligoesters by melting, and subsequently tested on in vitro albumin release. The linear poly (DL-lactic acid) and the branched terpolymer of DL-lactic acid, glycolic acid, and mannitol were synthesized. Products were of similar molecular weight and possessed different thermal and swelling characteristics. Oligoesters were loaded with 4% albumin and plasticized by 30% triacetin. Other additives added into the matrices as albumin stabilizers were divalent stearates and magnesium oxide. The influences of oligomer molecules constitution, divalent ion stearates or magnesium oxide addition, and triacetin concentration on the albumin release were quantified. SDS-PAGE revealed protein hydrolysis during the dissolution tests.

  9. Lipase immobilized catalytically active membrane for synthesis of lauryl stearate in a pervaporation membrane reactor.

    PubMed

    Zhang, Weidong; Qing, Weihua; Ren, Zhongqi; Li, Wei; Chen, Jiangrong

    2014-11-01

    A composite catalytically active membrane immobilized with Candida rugosa lipase has been prepared by immersion phase inversion technique for enzymatic synthesis of lauryl stearate in a pervaporation membrane reactor. SEM images showed that a "sandwich-like" membrane structure with a porous lipase-PVA catalytic layer uniformly coated on a polyvinyl alcohol (PVA)/polyethersulfone (PES) bilayer was obtained. Optimum conditions for lipase immobilization in the catalytic layer were determined. The membrane was proved to exhibit superior thermal stability, pH stability and reusability than free lipase under similar conditions. In the case of pervaporation coupled synthesis of lauryl stearate, benefited from in-situ water removal by the membrane, a conversion enhancement of approximately 40% was achieved in comparison to the equilibrium conversion obtained in batch reactors. In addition to conversion enhancement, it was also found that excess water removal by the catalytically active membrane appears to improve activity of the lipase immobilized.

  10. Effects of Sucrose Stearate Addition on the Quality Improvement of Ready-To-Eat Samgyetang During Storage at 25℃

    PubMed Central

    2014-01-01

    The effects of sucrose stearate at various concentrations (0.1%, 0.2%, and 0.3%, w/v) on the physico-chemical characteristics of ready-to-eat (RTE) Samgyetang were investigated during storage at 25℃ for 12 mon. Over the storage duration, the addition of sucrose stearate had no significant effects on the proximate composition of Samgyetang, including meat, broth, and porridge, or the hardness and spreadability of the porridge, although it resulted in significantly higher CIE L* values for the porridge. The CIE L* values of Samgyetang porridge with added sucrose stearate increased until 9 mon, while the control decreased until 6 mon, and the values for both changed insignificantly thereafter. The breast meat of Samgyetang treated with sucrose stearate showed higher percentages of polyunsaturated fatty acid after 3 mon and lower percentages of monounsaturated fatty acid after 6 mon compared to the control (p<0.05), while no significant differences were observed with the different sucrose stearate concentrations (p>0.05). The overall sensory acceptability scores were higher at sucrose stearate concentrations of 0.2% or 0.3% after 6 mon and at 0.1% after 9 mon compared to those of the control. PMID:26761503

  11. A molecular dynamics study of CaCO3 nanoparticles in a hydrophobic solvent with a stearate co-surfactant.

    PubMed

    Bodnarchuk, Michael S; Heyes, David M; Breakspear, Angela; Chahine, Samir; Dini, Daniele

    2015-05-28

    Stearates containing overbased detergent nanoparticles (NPs) are used as acid neutralising additives in automotive and marine engine oils. Molecular dynamics (MD) simulations of the self-assembly of calcium carbonate, calcium stearate as a co-surfactant and stabilising surfactants of such NPs in a model explicit molecular hydrophobic solvent have been carried out using a methodology described first by Bodnarchuk et al. [J. Phys. Chem. C, 2014, 118, 21092]. The cores and particles as a whole become more elongated with stearate, and the surfactant molecules are more spaced out in this geometry than in their stearate-free counterparts. The rod dimensions are found to be largely independent of the surfactant type for a given amount of CaCO3. The corresponding particles without stearate were more spherical, the precise shape depending to a greater extent on the chemical architecture of the surfactant molecule. The rod-shaped stearate containing nanoparticles penetrated a model water droplet to a greater depth than the corresponding near-spherical particle, which is possibly facilitated by the dissociation of nanoparticle surfactant molecules onto the surface of the water in this process. These simulations are the first to corroborate the nanoparticle-water penetration mechanism proposed previously by experimental groups investigating the NP acid neutralisation characteristics.

  12. Effect of europium(II) stearate on the mechanical properties and the oxidation resistance of UHMWPE.

    PubMed

    Gallardo, Luis A; Knowlton, Christopher B; Kunze, Joachim; Jacobs, Joshua J; Wimmer, Markus A; Laurent, Michel P

    2011-07-01

    The objective of this pilot study is to investigate the effect of europium(II) stearate additive on the mechanical properties and oxidation resistance of an ultra-high molecular weight polyethylene (UHMWPE), which has been used as an articulating surface in prosthetic devices for many years. It is hypothesized in this study that combining the UHMWPE with lanthanide stearates could enhance oxidation resistance, leading to better preservation of the material's mechanical integrity. Compression molded UHMWPE was doped at 0, 375 and 750 ppm of europium(II) stearate, γ-irradiated to 35 kGy in a nitrogen atmosphere, and accelerated aged in accordance with the ASTM standard F2003-02. Non-irradiated and nonaged samples were used as controls. Miniature samples were comparatively tested for mechanical properties using the small punch test. Oxidation indices (OIs) were obtained through the FTIR spectroscopy on thin film sections of all irradiated samples. The UHMWPE doped with the europium(II) stearate had the same small punch test curve shape as the conventional UHMWPE control; the ultimate displacement remained unchanged (approximately 4.33±0.02 mm), while the ultimate load and work-to-failure exhibited only small changes (<7.5% and <5.0%, respectively). The doped material was more resistant to oxidation than the control material, retaining 83% of its as-irradiated work-to-failure after irradiation and accelerated aging, versus only 53% for the control. Accelerated aging changed the average oxidation index of the control group from 0.07 to 0.40; whereas the average oxidation indices changed from 0.03 to 0.15 and from 0.05 to 0.13 for the 375 ppm and the 750 ppm doped condition, respectively.

  13. Liquid crystal physical gel formed by cholesteryl stearate for light scattering display material.

    PubMed

    Leaw, W L; Mamat, C R; Triwahyono, S; Jalil, A A; Bidin, N

    2016-12-01

    A liquid crystal physical gel was prepared by the self-assembly of cholesteryl stearate in a nematic liquid crystal, 4-cyano-4'-pentylbiphenyl. The electro-optical properties were tuned by varying the gelator concentration and the gelation conditions. Polarized optical microscopy revealed that cholesteric cholesteryl stearate induced chiral nematic phase in 4-cyano-4'-pentylbiphenyl during the gelation process. As a result, a plate-like gel structure consisting of spherical micropores was formed, as observed by scanning electron microscopy. Electron spin resonance spectroscopy showed that the liquid crystal director orientations in these macrophase-separated structures were massively randomised. For these reasons, the liquid crystal physical gel generated a strong light scattering effect. For 48.0wt% cholesteryl stearate gelled 4-cyano-4'-pentylbiphenyl, the turbid appearance could be switched to a transparent state using a 5.0V alternating current. The response time was about 3.7μs. This liquid crystal physical gel has potential for use in light scattering electro-optical displays.

  14. Identification of isoliquiritigenin as an activator that stimulates the enzymatic production of glycyrrhetinic acid monoglucuronide.

    PubMed

    Wang, Xiaoxue; Wang, Dong; Huo, Yixin; Dai, Dazhang; Li, Chihua; Li, Chun; Liu, Guiyan

    2017-10-02

    Glycyrrhetinic acid monoglucuronide (GAMG) is a great value-added and has considerable commercial interest due to its strong pharmacological activities and functional low-calorie sweetener. However GAMG is quite rare in natural plants, and it must be prepared from glycyrrhizin (GL) by hydrolysing one terminal glucuronic acid. β-Glucuronidase is the key enzyme in the biotransformation of GL to GAMG, but its activities need to be enhanced to facilitate the industrial large-scale production of GAMG. In this study, we identified that isoliquiritigenin (ISL), as one of chemical compositions from the total flavonoids glycyrrhiza (TFG), can significantly enhance β-glucuronidase activity in vitro. Measurements using high-performance liquid chromatography (HPLC) showed that the activity of β-glucuronidase could be increased by 2.66-fold via the addition of ISL to a β-glucuronidase solution that contained GL at a 3:10 molar ratio of ISL to GL. ISL was concluded to be an activator because ISL could reduce the Km and Ea of β-glucuronidase reacting with GL. This study sheds new light on the mechanism of β-glucuronidase and helps to make industrial production of GAMG through fermentation feasible.

  15. A Glycyrrhetinic Acid-Modified Curcumin Supramolecular Hydrogel for liver tumor targeting therapy

    NASA Astrophysics Data System (ADS)

    Chen, Guoqin; Li, Jinliang; Cai, Yanbin; Zhan, Jie; Gao, Jie; Song, Mingcai; Shi, Yang; Yang, Zhimou

    2017-03-01

    Curcumin (Cur), a phenolic anti-oxidant compound obtained from Curcuma longa plant, possesses a variety of therapeutic properties. However, it is suffered from its low water solubility and low bioavailability property, which seriously restricts its clinical application. In this study, we developed a glycyrrhetinic acid (GA) modified curcumin supramolecular pro-gelator (GA-Cur) and a control compound Nap-Cur by replacing GA with the naphthylacetic acid (Nap). Both compounds showed good water solubility and could form supramolecular gels by disulfide bond reduction triggered by glutathione (GSH) in vitro. Both formed gels could sustainedly release Cur in buffer solutions. We also investigated the cytotoxicity of pro-gelators to HepG2 cells by a MTT assay and determined the cellular uptake behaviours of them by fluorescence microscopy and LC-MS. Due to the over expression of GA receptor in liver cancer cells, our pro-gelator of GA-Cur showed an enhanced cellular uptake and better inhibition capacity to liver tumor cells than Nap-Cur. Therefore, the GA-Cur could significantly inhibit HepG2 cell growth. Our study provides a novel nanomaterial for liver tumor chemotherapy.

  16. An Overview of Structurally Modified Glycyrrhetinic Acid Derivatives as Antitumor Agents.

    PubMed

    Xu, Bing; Wu, Gao-Rong; Zhang, Xin-Yu; Yan, Meng-Meng; Zhao, Rui; Xue, Nan-Nan; Fang, Kang; Wang, Hui; Chen, Meng; Guo, Wen-Bo; Wang, Peng-Long; Lei, Hai-Min

    2017-06-02

    Glycyrrhetinic Acid (GA), a triterpenoid aglycone component of the natural product glycyrrhizinic acid, was found to possess remarkable anti-proliferative and apoptosis-inducing activity in various cancer cell lines. Though GA was not as active as other triterpenes, such as betulinic acid and oleanolic acid, it could trigger apoptosis in tumor cells and it can be obtained easily and cheaply, which has stimulated scientific interest in using GA as a scaffold to synthesize new antitumor agents. The structural modifications of GA reported in recent decades can be divided into four groups, which include structural modifications on ring-A, ring-C, ring-E and multiple ring modifications. The lack of a comprehensive and recent review on this topic prompted us to gather more new information. This overview is dedicated to summarizing and updating the structural modification of GA to improve its antitumor activity published between 2005 and 2016. We reviewed a total of 210 GA derivatives that we encountered and compiled the most active GA derivatives along with their activity profile in different series. Furthermore, the structure activity relationships of these derivatives are briefly discussed. The included information is expected to be of benefit to further studies of structural modifications of GA to enhance its antitumor activity.

  17. A Glycyrrhetinic Acid-Modified Curcumin Supramolecular Hydrogel for liver tumor targeting therapy

    PubMed Central

    Chen, Guoqin; Li, Jinliang; Cai, Yanbin; Zhan, Jie; Gao, Jie; Song, Mingcai; Shi, Yang; Yang, Zhimou

    2017-01-01

    Curcumin (Cur), a phenolic anti-oxidant compound obtained from Curcuma longa plant, possesses a variety of therapeutic properties. However, it is suffered from its low water solubility and low bioavailability property, which seriously restricts its clinical application. In this study, we developed a glycyrrhetinic acid (GA) modified curcumin supramolecular pro-gelator (GA-Cur) and a control compound Nap-Cur by replacing GA with the naphthylacetic acid (Nap). Both compounds showed good water solubility and could form supramolecular gels by disulfide bond reduction triggered by glutathione (GSH) in vitro. Both formed gels could sustainedly release Cur in buffer solutions. We also investigated the cytotoxicity of pro-gelators to HepG2 cells by a MTT assay and determined the cellular uptake behaviours of them by fluorescence microscopy and LC-MS. Due to the over expression of GA receptor in liver cancer cells, our pro-gelator of GA-Cur showed an enhanced cellular uptake and better inhibition capacity to liver tumor cells than Nap-Cur. Therefore, the GA-Cur could significantly inhibit HepG2 cell growth. Our study provides a novel nanomaterial for liver tumor chemotherapy. PMID:28281678

  18. A Glycyrrhetinic Acid-Modified Curcumin Supramolecular Hydrogel for liver tumor targeting therapy.

    PubMed

    Chen, Guoqin; Li, Jinliang; Cai, Yanbin; Zhan, Jie; Gao, Jie; Song, Mingcai; Shi, Yang; Yang, Zhimou

    2017-03-10

    Curcumin (Cur), a phenolic anti-oxidant compound obtained from Curcuma longa plant, possesses a variety of therapeutic properties. However, it is suffered from its low water solubility and low bioavailability property, which seriously restricts its clinical application. In this study, we developed a glycyrrhetinic acid (GA) modified curcumin supramolecular pro-gelator (GA-Cur) and a control compound Nap-Cur by replacing GA with the naphthylacetic acid (Nap). Both compounds showed good water solubility and could form supramolecular gels by disulfide bond reduction triggered by glutathione (GSH) in vitro. Both formed gels could sustainedly release Cur in buffer solutions. We also investigated the cytotoxicity of pro-gelators to HepG2 cells by a MTT assay and determined the cellular uptake behaviours of them by fluorescence microscopy and LC-MS. Due to the over expression of GA receptor in liver cancer cells, our pro-gelator of GA-Cur showed an enhanced cellular uptake and better inhibition capacity to liver tumor cells than Nap-Cur. Therefore, the GA-Cur could significantly inhibit HepG2 cell growth. Our study provides a novel nanomaterial for liver tumor chemotherapy.

  19. Inhibitory Effects of Glycyrrhetinic Acid on DNA Polymerase and Inflammatory Activities

    PubMed Central

    Ishida, Tsukasa; Mizushina, Yoshiyuki; Yagi, Saori; Irino, Yasuhiro; Nishiumi, Shin; Miki, Ikuya; Kondo, Yasuyuki; Mizuno, Shigeto; Yoshida, Hiromi; Azuma, Takeshi; Yoshida, Masaru

    2012-01-01

    We investigated the inhibitory effect of three glycyrrhizin derivatives, such as Glycyrrhizin (compound 1), dipotassium glycyrrhizate (compound 2) and glycyrrhetinic acid (compound 3), on the activity of mammalian pols. Among these derivatives, compound 3 was the strongest inhibitor of mammalian pols α, β, κ, and λ, which belong to the B, A, Y, and X families of pols, respectively, whereas compounds 1 and 2 showed moderate inhibition. Among the these derivatives tested, compound 3 displayed strongest suppression of the production of tumor necrosis factor-α (TNF-α) induced by lipopolysaccharide (LPS) in a cell-culture system using mouse macrophages RAW264.7 and peritoneal macrophages derived from mice. Moreover, compound 3 was found to inhibit the action of nuclear factor-κB (NF-κB) in engineered human embryonic kidney (HEK) 293 cells. In addition, compound 3 caused greater reduction of 12-O-tetradecanoylphorbol-13-acetate-(TPA-) induced acute inflammation in mouse ear than compounds 1 and 2. In conclusion, this study has identified compound 3, which is the aglycone of compounds 1 and 2, as a promising anti-inflammatory candidate based on mammalian pol inhibition. PMID:21785649

  20. Anti-tumor agents 255: novel glycyrrhetinic acid-dehydrozingerone conjugates as cytotoxic agents.

    PubMed

    Tatsuzaki, Jin; Taniguchi, Masahiko; Bastow, Kenneth F; Nakagawa-Goto, Kyoko; Morris-Natschke, Susan L; Itokawa, Hideji; Baba, Kimiye; Lee, Kuo-Hsiung

    2007-09-15

    Esterification of glycyrrhetinic acid (GA) with dehydrozingerone (DZ) resulted in a novel cytotoxic GA-DZ conjugate. Based on this exciting finding, we conjugated eleven different DZ analogs with GA or other triterpenoids, including oleanoic acid (OA) or ursolic acid (UA). In an in vitro anti-cancer assay using nine different human tumor cell lines, most of the GA-DZ conjugates showed significant potency. Particularly, compounds 5, 29, and 30 showed significant cytotoxic effects against LN-Cap, 1A9, and KB cells with ED(50) values of 0.6, 0.8, and 0.9 microM, respectively. Similar conjugates between DZ and OA or UA were inactive suggesting that the GA component is critical for activity. Notably, although GA-DZ conjugates showed potent cytotoxic activity, the individual components (GA and DZ analogs) were inactive. Thus, GA-DZ conjugates are new chemical entities and represent interesting hits for anti-cancer drug discovery and development.

  1. Novel 18beta-glycyrrhetinic acid analogues as potent and selective inhibitors of 11beta-hydroxysteroid dehydrogenases.

    PubMed

    Su, Xiangdong; Lawrence, Harshani; Ganeshapillai, Dharshini; Cruttenden, Adrian; Purohit, Atul; Reed, Michael J; Vicker, Nigel; Potter, Barry V L

    2004-08-15

    Extensive structural modifications to the 18beta-glycyrrhetinic acid template are described and their effects on the SAR of the 11beta-hydroxysteroid dehydrogenase isozymes type 1 and 2 from the rat are investigated. Isoform selective inhibitors have been discovered and compound 7 N-(2-hydroxyethyl)-3beta-hydroxy-11-oxo-18beta-olean-12-en-30-oic acid amide is highlighted as a very potent selective inhibitor of 11beta-hydroxysteroid dehydrogenase 2 with an IC(50) = 4pM.

  2. Can active components of licorice, glycyrrhizin and glycyrrhetinic acid, lick rheumatoid arthritis?

    PubMed Central

    Huang, Qing-Chun; Wang, Mao-Jie; Chen, Xiu-Min; Yu, Wan-Lin; Chu, Yong-Liang; He, Xiao-Hong; Huang, Run-Yue

    2016-01-01

    OBJECTIVES This review stated the possible application of the active components of licorice, glycyrrhizin (GL) and glycyrrhetinic acid (GA), in rheumatoid arthritis (RA) treatment based on the cyclooxygenase (COX)-2/thromboxane A2 (TxA2) pathway. METHODS The extensive literature from inception to July 2015 was searched in PubMed central, and relevant reports were identified according to the purpose of this study. RESULTS The active components of licorice GL and GA exert the potential anti-inflammatory effects through, at least in part, suppressing COX-2 and its downstream product TxA2. Additionally, the COX-2/TxA2 pathway, an auto-regulatory feedback loop, has been recently found to be a crucial mechanism underlying the pathogenesis of RA. However, TxA2 is neither the pharmacological target of non-steroidal anti-inflammatory drugs (NSAIDs) nor the target of disease modifying anti-rheumatic drugs (DMARDs), and the limitations and side effects of those drugs may be, at least in part, attributable to lack of the effects on the COX-2/TxA2 pathway. Therefore, GL and GA capable of targeting this pathway hold the potential as a novel add-on therapy in therapeutic strategy, which is supported by several bench experiments. CONCLUSIONS The active components of licorice, GL and GA, could not only potentiate the therapeutic effects but also decrease the adverse effects of NSAIDs or DMARDs through suppressing the COX-2/TxA2 pathway during treatment course of RA. PMID:26498361

  3. Laminaria japonica increases plasma exposure of glycyrrhetinic acid following oral administration of Liquorice extract in rats.

    PubMed

    Zhao, Wei-Man; Jiang, Shu-Wen; Chen, Yang; Zhong, Ze-Yu; Wang, Zhong-Jian; Zhang, Mian; Li, Ying; Xu, Ping; Liu, Li; Liu, Xiao-Dong

    2015-07-01

    The present study was designed to investigate the effects of Laminaria japonica (Laminaria) on pharmacokinetics of glycyrrhetinic acid (GA) following oral administration of Liquorice extract in rats. Following oral administrations of single-dose and multi-dose Liquorice extract and Liquorice-Laminaria extract, respectively, plasma samples were obtained at various times and the concentrations of GA, liquiritigenin, and isoliquiritigenin were measured by LC-MS. The effects of Laminaria extract on pharmacokinetics of GA were also investigated, following single-dose and multidose of glycyrrhizic acid (GL). The effects of Laminaria extract on intestinal absorption of GA and GL were studied using the in situ single-pass intestinal perfusion model. The metabolism of GL to GA in the contents of small and large intestines was also studied. The results showed Liquorice-Laminaria extract markedly increased the plasma concentration of GA, accompanied by a shorter Tmax. Similar alteration was observed following multidose administration. However, pharmacokinetics of neither liquiritigenin nor isoliquiritigenin was affected by Laminaria. Similarly, Laminaria markedly increased concentration and decreased Tmax of GA following oral GL were observed. The data from the intestinal perfusion model showed that Laminaria markedly increased GL absorption in duodenum and jejunum, but did not affect the intestinal absorption of GA. It was found that Laminaria enhanced the metabolism of GL to GA in large intestine. In conclusion, Laminaria increased plasma exposures of GA following oral administration of liquorice or GL, which partly resulted from increased intestinal absorption of GL and metabolism of GL to GA in large intestine. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  4. Effects of the gap junction blocker glycyrrhetinic acid on gastrointestinal smooth muscle cells.

    PubMed

    Takeda, Yukari; Ward, Sean M; Sanders, Kenton M; Koh, Sang Don

    2005-04-01

    In the tunica muscularis of the gastrointestinal (GI) tract, gap junctions form low-resistance pathways between pacemaker cells known as interstitial cells of Cajal (ICCs) and between ICC and smooth muscle cells. Coupling via these junctions facilitates electrical slow-wave propagation and responses of smooth muscle to enteric motor nerves. Glycyrrhetinic acid (GA) has been shown to uncouple gap junctions, but previous studies have shown apparent nonspecific effects of GA in a variety of tissues. We tested the effects of GA using isometric force measurements, intracellular microelectrode recordings, the patch-clamp technique, and the spread of Lucifer yellow within cultured ICC networks. In murine small intestinal muscles, beta-GA (10 muM) decreased phasic contractions and depolarized resting membrane potential. Preincubation of GA inhibited the spread of Lucifer yellow, increased input resistance, and decreased cell capacitance in ICC networks, suggesting that GA uncoupled ICCs. In patch-clamp experiments of isolated jejunal myocytes, GA significantly decreased L-type Ca(2+) current in a dose-dependent manner without affecting the voltage dependence of this current. The IC(50) for Ca(2+) currents was 1.9 muM, which is lower than the concentrations used to block gap junctions. GA also significantly increased large-conductance Ca(2+)-activated K(+) currents but decreased net delayed rectifier K(+) currents, including 4-aminopyridine and tetraethylammonium-resistant currents. In conclusion, the reduction of phasic contractile activity of GI muscles by GA is likely a consequence of its inhibitory effects on gap junctions and voltage-dependent Ca(2+) currents. Membrane depolarization may be a consequence of uncoupling effects of GA on gap junctions between ICCs and smooth muscles and inhibition of K(+) conductances in smooth muscle cells.

  5. The effect of glycyrrhetinic acid on pharmacokinetics of cortisone and its metabolite cortisol in rats.

    PubMed

    Lin, Dan; Sun, Wei; Wang, Zhe; Chen, Lian-Guo; Chen, Xiao-Le; Wang, Shuang-Hu; Li, Wan-Shu; Ge, Ren-Shan; Hu, Guo-Xin

    2012-01-01

    The purpose of this paper is to study pharmacokinetics of cortisone (E) and its metabolite cortisol (F) in rats after administration of glycyrrhetinic acid (GA) and cortisone. Healthy male SD rats were randomized to be given 20 mg/kg E or E combined with 10 mg/kg GA. Blood samples were collected at 5, 10, 20, 40, 60, 90, 120, 150, 180, and 240 min after administration. The serum concentrations of E and F were determined by HLPC and pharmacokinetic parameters were calculated using DASver2.0 software. The parameters of AUC((0-t)), AUC((0-∞)), and C(max) for E in the group of E + GA were significantly higher than those in the group of E (P < 0.01); the half-time (t(1/2β)) was extended compared to E (P < 0.05) and CL/F was dropped obviously (P < 0.01). The rise in AUC((0-t)), AUC((0-∞)), and C(max) for cortisol in the group of E + GA was significantly compared to the group of E (P < 0.01). CL/F was lower than E (P < 0.01) and the half-time (t(1/2β)) was slightly extended. In this study, we find that GA restrains the metabolism of E and F and thus increases AUC, t(1/2β), and C(max) of E and F, which may be related to its inhibition effect on 11β-hydroxysteroid dehydrogenase (11β-HSD).

  6. The Effect of Glycyrrhetinic Acid on Pharmacokinetics of Cortisone and Its Metabolite Cortisol in Rats

    PubMed Central

    Lin, Dan; Sun, Wei; Wang, Zhe; Chen, Lian-Guo; Chen, Xiao-Le; Wang, Shuang-Hu; Li, Wan-Shu; Ge, Ren-Shan; Hu, Guo-Xin

    2012-01-01

    The purpose of this paper is to study pharmacokinetics of cortisone (E) and its metabolite cortisol (F) in rats after administration of glycyrrhetinic acid (GA) and cortisone. Healthy male SD rats were randomized to be given 20 mg/kg E or E combined with 10 mg/kg GA. Blood samples were collected at 5, 10, 20, 40, 60, 90, 120, 150, 180, and 240 min after administration. The serum concentrations of E and F were determined by HLPC and pharmacokinetic parameters were calculated using DASver2.0 software. The parameters of AUC(0−t), AUC(0−∞), and Cmax for E in the group of E + GA were significantly higher than those in the group of E (P < 0.01); the half-time (t1/2β) was extended compared to E (P < 0.05) and CL/F was dropped obviously (P < 0.01). The rise in AUC(0−t), AUC(0−∞), and Cmax for cortisol in the group of E + GA was significantly compared to the group of E (P < 0.01). CL/F was lower than E (P < 0.01) and the half-time (t1/2β) was slightly extended. In this study, we find that GA restrains the metabolism of E and F and thus increases AUC, t1/2β, and Cmax of E and F, which may be related to its inhibition effect on 11β-hydroxysteroid dehydrogenase (11β-HSD). PMID:23258958

  7. Microstructure and Electrical Resistivity of Low-Temperature-Cured Silver Films Prepared Using Silver Oxide and Silver Stearate Pastes

    NASA Astrophysics Data System (ADS)

    Lin, Hong-Ching; Lin, Pang; Lu, Chun-An; Wang, Sea-Fue

    2009-01-01

    In this study, paste formulations containing silver oxide coated with a metallo-organic decomposition (MOD) agent of silver stearate were prepared without using any silver powders or silver flakes. Results indicate that all pastes appear to have a pseudoplastic flow property that is acceptable for roll-to-roll printing and screen printing. The pastes were screen-printed on an alumina substrate and then thermally treated in a range of temperatures. The lowest electrical resistivity of 13.2 ×10-6 Ω·cm was obtained for the film prepared from paste with a Ag2O/silver stearate ratio of 100:5 at a solid loading of 80 wt % in the solvent α-terpineol, after being cured at 160 °C for 5 min, which meets the requirements of low-temperature and high-speed manufacturing for practical applications. The low resistivity of the film is facilitated by the combination of Ag2O and silver stearate added to the paste. Ag2O produces a high density of silver matrix after being reduced at low temperatures, and the presence of silver stearate contributes to the rheological behavior of the paste after dissolution in the solvent. Coexistence of Ag2O and silver stearate induces their simultaneous transformation to the silver form at temperatures below 160 °C.

  8. New generation of nuclear fuels: Stability of different stearates under high doses gamma irradiation in the manufacturing process

    NASA Astrophysics Data System (ADS)

    Lebeau, D.; Esnouf, S.; Gracia, J.; Audubert, F.; Ferry, M.

    2017-07-01

    In the future reactors, the pellets radioactivity will increase due to the modification of the plutonium concentration. The stability of the organic additive used as lubricating/deagglomerating agent has thus to be evaluated. Up to now, zinc stearate is employed, but new additives are tested in this study and compared to zinc stearate. In a first part of this paper, the order of magnitude of the dose deposited in the stearates has been estimated. Afterward, three different stearates have been irradiated, using gamma-rays at doses as high as 2000 kGy. Two atmospheres of irradiation were tested, i.e. inert atmosphere and air. Samples were characterized using the following analytical tools: mass spectrometry, thermogravimetry and infrared spectroscopy. The objective is the evaluation of the ageing of these materials. In the nuclear fuel pellets manufacturing context, the candidate which could replace zinc stearate, if this one is too degraded to fulfill its role of lubricant in the pellets of the future manufacturing, has been determined.

  9. Ageing effects on the magnetic properties of Mn12-based Acetate and Stearate SMMs

    NASA Astrophysics Data System (ADS)

    Verma, Apoorva; Verma, Shilpi; Singh, Priti; Gupta, Anurag

    2017-10-01

    A study of ageing effects on the magnetic properties of Single-Molecule-Magnets (SMMs) of the Mn12 based Acetate, ([Mn12O12(CH3COO)16(H2O)4]·2CH3COOH·4H2O (1) and Stearate, [Mn12O12(CH3(CH2)16COO)11(CH3COO)5(H2O)4] (2) complexes has been carried out. Detailed magnetization (M) measurements as a function of temperature (T ∼ 1.8-10 K), magnetic field (H ∼ 0 to ±40 kOe) and time (t) have been performed on relatively fresh samples (1A and 2A) and samples aged for ∼4 weeks (1B and 2B) of both Mn12-Acetate and Mn12-Stearate. The blocking temperatures (TB) extracted from the measured M(T) lie between ∼3.0 and 3.4 K for all the four samples. In all cases, below TB, the M-H loops exhibit hysteresis with periodic steps. Interestingly, the ageing process leads to significant changes in the magnetic response of both the complexes. With ageing the Mn12-Acetate exhibits a large increase in the magnetization drop near zero-field, but the estimated anisotropy energy barrier (U) remains unchanged ∼71 K. Whereas, in the case of Mn12-Stearate ageing results in a change of U from ∼52 K (2A) to ∼35 K (2B). The results are discussed in terms of possible ageing induced changes in the structural and chemical environment of the SMMs.

  10. Development of sucrose stearate-based nanoemulsions and optimisation through γ-cyclodextrin.

    PubMed

    Klang, Victoria; Matsko, Nadejda; Raupach, Karoline; El-Hagin, Nivine; Valenta, Claudia

    2011-09-01

    Nanoemulsions aimed at dermal drug delivery are usually stabilised by natural lecithins. However, lecithin has a high tendency towards self-aggregation and is prone to chemical degradation. Therefore, the aim of this study was to develop nanoemulsions with improved structure and long-term stability by employing a natural sucrose ester mixture as sole surfactant. A thorough comparison between the novel sucrose stearate-based nanoemulsions and corresponding lecithin-based nanoemulsions revealed that the sucrose ester is superior in terms of emulsifying efficiency, droplet formation as well as physical and chemical stability. The novel formulations exhibited a remarkably homogeneous structure in cryo TEM investigations, as opposed to the variable structure observed for lecithin-based systems. The in vitro skin permeation rates of lipophilic drugs from sucrose stearate nanoemulsions were comparable to those obtained with their lecithin-based counterparts. Furthermore, it was observed that addition of γ-cyclodextrin led to enhanced skin permeation of the steroidal drug fludrocortisone acetate from 9.99±0.46 to 55.10±3.67 μg cm(-2) after 24 h in the case of sucrose stearate-based systems and from 9.98±0.64 to 98.62±24.89 μg cm(-2) after 24 h in the case of lecithin-based systems. This enhancement effect was significantly stronger in formulations based on lecithin (P<0.05), which indicates that synergistic mechanisms between the surfactant and the cyclodextrin are involved. Cryo TEM images suggest that the cyclodextrin is incorporated into the interfacial film, which might alter drug release rates and improve the droplet microstructure. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Development of pH sensitive polymeric nanoparticles of erythromycin stearate

    PubMed Central

    Bhadra, Sulekha; Prajapati, Atin B.; Bhadra, Dipankar

    2016-01-01

    Context: Bioavailability of conventional tablet of erythromycin stearate is low as it is unstable at acidic pH and also shows a low dissolution rate. Objective: It was proposed to protect it from the acidic condition of the stomach along with an increase in dissolution rate by formulating pH sensitive nanoparticles. Materials and Methods: The nanoparticles were prepared by the solvent evaporation technique using different quantities of Eudragit L100-55 and polyvinyl alcohol (PVA). Size reduction was achieved by high speed homogenization technique using Digital Ultra Turrax homogenizer. The formulation was optimized using 32 factorial design, keeping drug polymer ratio and surfactant concentration as independent variables. Particle size, entrapment efficiency, and drug-release (DR) were studied as dependent variables. Results: Optimized batch containing 1:0.3 erythromycin stearate: Eudragit L100-55 ratio and 1.0% PVA showed 8.24 ± 0.71% DR in pH 1.2 in 1-h and 90.38 ± 5.97% in pH 5.5 and pH 6.8 within 2-h, respectively. Discussion: The optimized batch exhibited lower release in acidic pH and faster release in higher pH compared to the marketed preparation. Conclusion: Thus the present study concludes that pH sensitive nanoparticles of erythromycin stearate increases the dissolution of the drug in intestinal pH and also protect it from acidic pH, which may help in improving the bioavailability of erythromycin. PMID:27134466

  12. Synthesis of new glycyrrhetinic acid derived ring A azepanone, 29-urea and 29-hydroxamic acid derivatives as selective 11β-hydroxysteroid dehydrogenase 2 inhibitors.

    PubMed

    Gaware, Rawindra; Khunt, Rupesh; Czollner, Laszlo; Stanetty, Christian; Da Cunha, Thierry; Kratschmar, Denise V; Odermatt, Alex; Kosma, Paul; Jordis, Ulrich; Classen-Houben, Dirk

    2011-03-15

    Glycyrrhetinic acid, the metabolite of the natural product glycyrrhizin, is a well known nonselective inhibitor of 11β-hydroxysteroid dehydrogenase (11β-HSD) type 1 and type 2. Whereas inhibition of 11β-HSD1 is currently under consideration for treatment of metabolic diseases, such as obesity and diabetes, 11β-HSD2 inhibitors may find therapeutic applications in chronic inflammatory diseases and certain forms of cancer. Recently, we published a series of hydroxamic acid derivatives of glycyrrhetinic acid showing high selectivity for 11β-HSD2. The most potent and selective compound is active against human 11β-HSD2 in the low nanomolar range with a 350-fold selectivity over human 11β-HSD1. Starting from the lead compounds glycyrrhetinic acid and the hydroxamic acid derivatives, novel triterpene type derivatives were synthesized and analyzed for their biological activity against overexpressed human 11β-HSD1 and 11β-HSD2 in cell lysates. Here we describe novel 29-urea- and 29-hydroxamic acid derivatives of glycyrrhetinic acid as well as derivatives with the Beckman rearrangement of the 3-oxime to a seven-membered ring, and the rearrangement of the C-ring from 11-keto-12-ene to 12-keto-9(11)-ene. The combination of modifications on different positions led to compounds comprising further improved selective inhibition of 11β-HSD2 in the lower nanomolar range with up to 3600-fold selectivity.

  13. Characterization of Synthesized and Commercial Forms of Magnesium Stearate Using Differential Scanning Calorimetry, Thermogravimetric Analysis, Powder X-Ray Diffraction, and Solid-State NMR Spectroscopy.

    PubMed

    Delaney, Sean P; Nethercott, Matthew J; Mays, Christopher J; Winquist, Nickolas T; Arthur, Donia; Calahan, Julie L; Sethi, Manish; Pardue, Daniel S; Kim, Junghyun; Amidon, Gregory; Munson, Eric J

    2017-01-01

    Magnesium stearate is the salt of a complex mixture of fatty acids, with the majority being stearate and palmitate. It has multiple crystalline forms and, potentially, an amorphous form. Magnesium stearate is used in the pharmaceutical manufacturing industry as a powder lubricant, and typically is added at low levels (∼1%) during the manufacturing process and blended for a relatively short time (∼5 min). Proper levels and mixing times are needed, as too short a mixing time or too small a quantity will result in improper lubrication, and too much can negatively impact dissolution rates. The complex mixture of multiple fatty acids and crystalline forms in magnesium stearate leads to variability between commercial sources, and switching between sources can impact both the amount of lubricant and mixing time needed for proper lubrication. In order to better understand the complex nature of magnesium stearate, a variety of analytical techniques were used to characterize both synthesized and commercial magnesium stearate samples. The results show that correlation among differential scanning calorimetry, thermogravimetric analysis, solid-state NMR spectroscopy, and other techniques provides a unique insight into the forms of magnesium stearate. Finally, the ability to monitor form changes of magnesium stearate in an intact tablet using solid-state NMR spectroscopy is shown. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  14. Superhydrophobic honeycomb-like cobalt stearate thin films on aluminum with excellent anti-corrosion properties

    NASA Astrophysics Data System (ADS)

    Xiong, Jiawei; Sarkar, D. K.; Chen, X.-Grant

    2017-06-01

    Superhydrophobic cobalt stearate thin films with excellent anti-corrosion properties were successfully fabricated on aluminum substrates via electrodeposition process. The water-repellent properties were attributed to the honeycomb-like micro-nano structure as well as low surface energy of cobalt stearate. The correlation between the surface morphology, composition as well as wetting properties and the molar ratio of inorganic cobalt salt (Co(NO3)2) and organic stearic acid (SA) abbreviated as Co/SA, in the electrolyte were studied carefully. The optimum superhydrophobic surface obtained on the electrodeposited cathodic aluminum substrate, in the mixed ethanolic solution with Co/SA molar ratio of 0.2, was found to have a maximum contact angle of 161°. The polarization resistance of superhydrophobic aluminum substrates was calculated as high as 1591 kΩ cm2, which is determined to be two orders of magnitude larger than that of the as-received aluminum substrate as 27 kΩ cm2. Electrochemical impedance spectroscopy (EIS) was also employed to evaluate the corrosion resistance properties of these samples. Furthermore, electrical equivalent circuits (EEC) have been suggested in order to better understand the corrosion phenomena on these surfaces based on the corresponding EIS data.

  15. Difference in the lubrication efficiency of bovine and vegetable-derived magnesium stearate during tabletting.

    PubMed

    Gupta, Abhay; Hamad, Mazen L; Tawakkul, Mobin; Sayeed, Vilayat A; Khan, Mansoor A

    2009-01-01

    The purpose of this work was to evaluate and compare the functionality of bovine fatty acids-derived (MgSt-B) and vegetable fatty acids-derived (MgSt-V) magnesium stearate powders when used for the lubrication of granules prepared by high-shear (HSG) and fluid bed (FBG) wet granulation methods. The work included evaluation of tablet compression and ejection forces during tabletting and dissolution testing of the compressed tablets. Granules prepared by both granulation methods required significantly lower ejection force (p < 0.01) when lubricated with the MgSt-V powder as compared to those lubricated with the MgSt-B powder. Granules prepared by the HSG method and lubricated with the MgSt-V powder also required significantly lower compression force (p < 0.01) to produce tablets of similar weight and hardness as compared to those lubricated with the MgSt-B powder. The dissolution profiles were not affected by these differences and were the same for tablets prepared by same granulation method and lubricated with either magnesium stearate powder. The results indicate significant differences (p < 0.01) between lubrication efficiency of the MgSt-B and the MgSt-V powders and emphasize the importance of functionality testing of the MgSt powders to understand the impact of these differences.

  16. Impact of moisture and magnesium stearate functionality on manufacturability of wet granulated metformin tablets.

    PubMed

    Kestur, Umesh; Desai, Divyakant; Sharif, Shasad; Wong, Benjamin; Guo, Hang; Tang, Dan; Chan, Steven

    2017-09-01

    During the development of a wet granulated 850 mg metformin hydrochloride tablet formulation, the tablets exhibited high friability (>3% w/w) irrespective of the source of extra-granular magnesium stearate (MgSt). High friability values indicated that an anti-bonding effect of MgSt was too high to be overcome by 3.3% w/w povidone as a binder in the formulation with 1.5% w/w residual granule moisture. Increasing the povidone concentration up to 7% w/w showed limited improvement in friability, with tablets showing variable friability depending on MgSt source. Characterization of MgSt indicated differences in crystallinity, surface area and particle morphology between different vendors. In addition, a new bulk yield strength test, which determines the MgSt fragmentation tendency, was found to be indicative of the MgSt performance in the tablet formulation. To improve bonding properties of granules, residual granule moisture was increased to 2% w/w at different povidone concentrations. At 2% w/w residual granule moisture content, regardless of MgSt source, the tablets showed significant improvement in friability (∼0.6% w/w) even at the lowest povidone concentration (3.3% w/w). The bonding power of higher residual granule moisture had a greater impact than higher povidone concentration in overcoming the anti-bonding effects of magnesium stearate.

  17. Sucrose stearate-based proniosome-derived niosomes for the nebulisable delivery of cromolyn sodium.

    PubMed

    Abd-Elbary, A; El-laithy, H M; Tadros, M I

    2008-06-05

    A Novel approach was developed for the preparation of controlled release proniosome-derived niosomes, using sucrose stearates as non-ionic biocompatible surfactants for the nebulisable delivery of cromolyn sodium. Conventional niosomes were prepared by a reverse phase evaporation method followed by the preparation of proniosomes by spraying the optimized surfactant-lipid mixture of sucrose stearate, cholesterol and stearylamine in 7:3:0.3 molar ratio onto the surface of spray dried lactose powder. Proniosome-derived niosomes were obtained by hydrating proniosomes with 0.9% saline at 50 degrees C and mixing for approximately 2 min. All vesicles were evaluated for their particle size, morphological characteristics, entrapment efficiency, in vitro drug release, nebulisation efficiency and physical stability at 2-8 degrees C. In addition, coating carrier surface with the surfactant-lipid mixture, during preparation of proniosomes, resulted in smaller, free flowing, homogenous and smooth vesicles with high drug entrapment efficiency. Compared to a standard drug solution, a successful retardation of the drug release rate was achieved with the proniosome-derived niosomes, where the t50% value of the release profile was 18.1h compared to 1.8h. Moreover, high nebulisation efficiency percentage and good physical stability were also achieved. The results are very encouraging and offer an alternative approach to minimize the problems associated with conventional niosomes like degradation, sedimentation, aggregation and fusion.

  18. An attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopic study of gas adsorption on colloidal stearate-capped ZnO catalyst substrate.

    PubMed

    Silverwood, Ian P; Keyworth, Colin W; Brown, Neil J; Shaffer, Milo S P; Williams, Charlotte K; Hellgardt, Klaus; Kelsall, Geoff H; Kazarian, Sergei G

    2014-01-01

    Attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy has been applied in situ to study gas adsorption on a colloidal stearate-capped zinc oxide (ZnO) surface. Infrared spectra of a colloidal stearate-capped ZnO catalyst substrate were assigned at room temperature using zinc stearate as a reference compound. Heating was shown to create a monodentate species that allowed conformational change to occur, leading to altered binding geometry of the stearate ligands upon cooling. CO2 and H2 adsorption measurements demonstrated that the ligand shell was permeable and did not cover the entire surface, allowing adsorption and reaction with at least some portion of the ZnO surface. It has been demonstrated that stearate ligands did not prevent the usual chemisorption processes involved in catalytic reactions on a model ZnO catalyst system, yet the ligand-support system is dynamic under representative reaction conditions.

  19. Glycyrrhetinic acid might increase the nephrotoxicity of bakuchiol by inhibiting cytochrome P450 isoenzymes

    PubMed Central

    Zhao, Zijing; Yuan, Mei

    2016-01-01

    Background Licorice, a popular traditional Chinese medicine (TCM), is widely used to moderate the effects (detoxification) of other herbs in TCM and often combined with Fructus Psoraleae. However, the classical TCM book states that Fructus Psoraleae is incompatible with licorice; the mechanism underlying this incompatibility has not been identified. Glycyrrhetinic acid (GA), the active metabolite of licorice, may increase the toxicity of bakuchiol (BAK), the main chemical ingredient in Psoralea corylifolia, by inhibiting its detoxification enzymes CYP450s. Methods The effect of concomitant GA administration on BAK-induced nephrotoxicity was investigated, and the metabolic interaction between BAK and GA was further studied in vitro and in vivo. The cytotoxicity was assessed using an MTT assay in a co-culture model of HK-2 cell and human liver microsomes (HLMs). The effect of GA on the metabolism of BAK, and on the activities of CYP isoforms were investigated in HLMs. The toxicokinetics and tissue exposure of BAK as well as the renal and hepatic functional markers were measured after the administration of a single oral dose in rats. Results In vitro studies showed that the metabolic detoxification of BAK was significantly reduced by GA, and BAK was toxic to HK-2 cells, as indicated by 25∼40% decreases in viability when combined with GA. Further investigation revealed that GA significantly inhibited the metabolism of BAK in HLMs in a dose-dependent manner. GA strongly inhibits CYP3A4 and weakly inhibits CYP2C9 and CYP1A2; these CYP isoforms are involved in the metabolism of BAK. In vivo experiment found that a single oral dose of BAK combined with GA or in the presence of 1-aminobenzotriazole (ABT), altered the toxicokinetics of BAK in rats, increased the internal exposure, suppressed the elimination of BAK prototype, and therefore may have enhanced the renal toxicity. Conclusion The present study demonstrated that GA inhibits CYP isoforms and subsequently may

  20. 18{beta}-Glycyrrhetinic acid inhibits adipogenic differentiation and stimulates lipolysis

    SciTech Connect

    Moon, Myung-Hee; Jeong, Jae-Kyo; Lee, You-Jin; Seol, Jae-Won; Ahn, Dong-Choon; Kim, In-Shik; Park, Sang-Youel

    2012-04-20

    Highlights: Black-Right-Pointing-Pointer 18{beta}-GA inhibits adipogenic differentiation in 3T3-L1 preadipocytes and stimulates lipolysis in differentiated adipocytes. Black-Right-Pointing-Pointer Anti-adipogenic effect of 18{beta}-GA is caused by down-regulation of PPAR{gamma} and inactivation of Akt signalling. Black-Right-Pointing-Pointer Lipolytic effect of 18{beta}-GA is mediated by up-regulation of HSL, ATGL and perilipin and activation of HSL. -- Abstract: 18{beta}-Glycyrrhetinic acid (18{beta}-GA) obtained from the herb liquorice has various pharmacological properties including anti-inflammatory and anti-bacterial activities. However, potential biological anti-obesity activities are unclear. In this study, novel biological activities of 18{beta}-GA in the adipogenesis of 3T3-L1 preadipocytes and in lipolysis of differentiated adipocytes were identified. Mouse 3T3-L1 cells were used as an in vitro model of adipogenesis and lipolysis, using a mixture of insulin/dexamethasone/3-isobutyl-1-methylxanthine (IBMX) to induce differentiation. The amount of lipid droplet accumulation was determined by an AdipoRed assay. The expression of several adipogenic transcription factors and enzymes was investigated using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. 18{beta}-GA dose-dependently (1-40 {mu}M) significantly decreased lipid accumulation in maturing preadipocytes. In 3T3-L1 preadipocytes, 10 {mu}M of 18{beta}-GA down-regulated the transcriptional levels of the peroxisome proliferator-activated receptor {gamma}, CCAAT/enhancer-binding protein {alpha} and adiponectin, which are markers of adipogenic differentiation via Akt phosphorylation. Also, in differentiated adipocytes, 18{beta}-GA increased the level of glycerol release and up-regulated the mRNA of hormone-sensitive lipase, adipose TG lipase and perilipin, as well as the phosphorylation of hormone-sensitive lipase at Serine 563. The results indicate that 18{beta

  1. 18β-Glycyrrhetinic Acid Derivatives Possessing a Trihydroxylated A Ring Are Potent Gram-Positive Antibacterial Agents.

    PubMed

    Huang, Li-Rong; Hao, Xiao-Jiang; Li, Qi-Ji; Wang, Dao-Ping; Zhang, Jian-Xin; Luo, Heng; Yang, Xiao-Sheng

    2016-04-22

    The oleanane-type triterpene 18β-glycyrrhetinic acid (1) was modified chemically through the introduction of a trihydroxylated A ring and an ester moiety at C-20 to enhance its antibacterial activity. Compounds 22, 23, 25, 28, 29, 31, and 32 showed more potent inhibitory activity against Streptomyces scabies than the positive control, streptomycin. Additionally, the inhibitory activity of the most potent compound, 29, against Bacillus subtilis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus was greater than that of the positive controls. The antibacterial mode of action of the active derivatives involved the regulation of the expression of genes associated with peptidoglycans, the respiratory metabolism, and the inherent virulence factors found in bacteria, as determined through a quantitative real-time reverse transcriptase PCR assay.

  2. Influence of magnesium stearate on the physicochemical and pharmacodynamic characteristics of insulin-loaded Eudragit entrapped mucoadhesive microspheres.

    PubMed

    Momoh, Mumuni A; Kenechukwu, Franklin C; Nnamani, Petra O; Umetiti, Jennifer C

    2015-01-01

    Effective oral insulin delivery has remained a challenge to the pharmaceutical industry. This study was designed to evaluate the effect of magnesium stearate on the properties of insulin-loaded Eudragit® RL 100 entrapped mucoadhesive microspheres. Microspheres containing Eudragit® RL 100, insulin, and varying concentrations of magnesium stearate (agglomeration-preventing agent) were prepared by emulsification-coacervation method and characterized with respect to differential scanning calorimetry (DSC), morphology, particle size, loading efficiency, mucoadhesive and micromeritics properties. The in vitro release of insulin from the microspheres was performed in simulated intestinal fluid (SIF, pH 7.2) while the in vivo hypoglycemic effect was investigated by monitoring the plasma glucose level of the alloxan-induced diabetic rats after oral administration. Stable, spherical, brownish, mucoadhesive, discrete and free flowing insulin-loaded microspheres were formed. While the average particle size and mucoadhesiveness of the microspheres increased with an increase in the proportion of magnesium stearate, loading efficiency generally decreased. After 12 h, microspheres prepared with Eudragit® RL 100: magnesium stearate ratios of 15:1, 15:2, 15:3 and 15:4 released 68.20 ± 1.57, 79.40 ± 1.52, 76.60 ± 1.93 and 70.00 ± 1.00 (%) of insulin, respectively. Reduction in the blood glucose level for the subcutaneously (sc) administered insulin was significantly (p ≤ 0.05) higher than for most of the formulations. However, the blood glucose reduction effect produced by the orally administered insulin-loaded microspheres prepared with four parts of magnesium stearate and fifteen parts of Eudragit® RL 100 after 12 h was equal to that produced by subcutaneously administered insulin solution. The results of this study can suggest that this carrier system could be an alternative for the delivery of insulin.

  3. Reduction in cholesterol absorption is enhanced by stearate-enriched plant sterol esters in hamsters.

    PubMed

    Rasmussen, Heather E; Guderian, David M; Wray, Curtis A; Dussault, Patrick H; Schlegel, Vicki L; Carr, Timothy P

    2006-11-01

    Consumption of plant sterol esters reduces plasma LDL cholesterol concentration by inhibiting intestinal cholesterol absorption. Commercially available plant sterol esters are prepared by esterifying free sterols to fatty acids from edible plant oils such as canola, soybean, and sunflower. To determine the influence of the fatty acid moiety on cholesterol metabolism, plant sterol esters were made with fatty acids from soybean oil (SO), beef tallow (BT), or purified stearic acid (SA) and fed to male hamsters for 4 wk. A control group fed no plant sterol esters was also included. Hamsters fed BT and SA had significantly lower cholesterol absorption and decreased concentrations of plasma non-HDL cholesterol and liver esterified cholesterol, and significantly greater fecal sterol excretion than SO and control hamsters. Cholesterol absorption was lowest in hamsters fed SA (7.5%), whereas it was 72.9% in control hamsters. Cholesterol absorption was correlated with fecal sterol excretion (r = -0.72, P < 0.001), liver cholesterol concentration (r = 0.88, P < 0.001), and plasma non-HDL cholesterol concentration (r = 0.85, P < 0.001). A multiple regression model that included each sterol ester type vs. cholesterol absorption indicated that intake of steryl stearate was the only dietary component that contributed significantly to the model (R2 = -0.75, P < 0.001). Therefore, our results demonstrate that BT and SA are more effective than SO in reducing cholesterol absorption, liver cholesterol, and plasma non-HDL cholesterol concentration, suggesting that cardioprotective benefits can be achieved by consuming stearate-enriched plant sterol esters.

  4. Phytosterol stearate esters elicit similar responses on plasma lipids and cholesterol absorption but different responses on fecal neutral sterol excretion and hepatic free cholesterol in male Syrian hamsters.

    PubMed

    Ash, Mark M; Hang, Jiliang; Dussault, Patrick H; Carr, Timothy P

    2011-07-01

    The dietary impact of specific phytosterols incorporated into phytosterol fatty acid esters has not been elucidated. Therefore, we tested the hypothesis that phytosterol esters containing different sterol moieties (sitosterol, sitostanol, or stigmasterol) but the same fatty acid moiety (stearic acid) produce different effects on cholesterol metabolism. Male Syrian hamsters were fed sitosterol, sitostanol, and stigmasterol stearate esters (25 g/kg diet) in an atherogenic diet containing cholesterol (1.2 g/kg) and coconut oil (80 g/kg). The phytosterol stearates produced no decrease in cholesterol absorption or plasma non-high-density lipoprotein cholesterol despite a reduction in liver free cholesterol in hamsters fed both sitosterol and sitostanol stearate diets. In addition, sitosterol stearate significantly increased fecal esterified and total neutral sterol excretion. Stigmasterol stearate did not differ from control in neutral sterol excretion, plasma lipids, or hepatic lipid concentration. Sitosterol stearate demonstrated the highest level of net intestinal hydrolysis, whereas sitostanol and stigmasterol stearate equivalently demonstrated the lowest. The cholesterol-lowering effect in liver-but not plasma-and the limited presence of fecal free sterols indicate that intact (unhydrolyzed) phytosterol stearates may impact cholesterol metabolism by mechanisms unrelated to the role of free phytosterols. The consumption of phytosterol esters at 2.5% of the diet elicited only modest impacts on cholesterol metabolism, although sitosterol stearate had a slightly greater therapeutic impact by lowering liver free cholesterol and increasing esterified and total neutral sterol fecal excretion, possibly due to a greater level of intestinal hydrolysis. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. [Effects of penetration enhancers on in vitro percutaneous absorption and amount retained in skin of paeonol, dictamnine, fraxinellone and glycyrrhetinic acid in Liangfu cream].

    PubMed

    Wang, Sen; Zhu, Weifeng; Ou, Shuiping; Guan, Yongmeii; Chen, Lihua; Yang, Ming

    2009-07-01

    To study the effects of different penetration enhancers on the in vitro percutaneous absorption and amount retained in skin of active ingredients in Liangfu cream and to screen out the effective accelerator. Using improved Franz-type difusion cell and excised small mouse skin in vitro as transdermal barrier, the amount retained in skin and kinetics parameters of active ingredients such as cumulative permeation quantity, permeation rate and permeation lagged time were determined by HPLC. The enhancement ability of four different enhancers such as azone, oleic acid, transcutol P and isopropyl myristate were investigated. 3% IPM enhanced the cumulative permeation quantity better than other penetration enhancers. The enhancive permeation multiples of paeonol, dictamnine, fraxinellone and glycyrrhetinic acid were 1.52, 1.24, 1.73 and 3.21 times (P < 0.05). The enhancive amount retained in skin multiple of glycyrrhetinic acid was 1.96 times (P < 0.05), but for other components there were no significant impacts. The effects of penetration enhancers on the in vitro percutaneous absorption and amount retained in skin of components in Liangfu cream are different. 3% IPM which can enhance the cumulative permeation quantity of four components and amount retained in skin of glycyrrhetinic acid is the most suitable penetration enhancer for Liangfu cream.

  6. Permeability of water and oleic acid in composite films of phase separated polypropylene and cellulose stearate blends.

    PubMed

    Krasnou, Illia; Gårdebjer, Sofie; Tarasova, Elvira; Larsson, Anette; Westman, Gunnar; Krumme, Andres

    2016-11-05

    Cellulose esters with long carbon side chains (e.g. stearate) were produced via a homogenous reaction in ionic liquids. The degree of substitution was calculated to approximately 2. The melt rheology was studied for the pure cellulose esters but also combinations of the esters and polypropylene to study the processability of a blended composite material. It was shown that the compatibility between the two components was weak, which resulted in a phase-separated composite material. The morphology and permeability of water and oleic acid of the composite films were studied and it was shown that the water permeability decreased upon addition of the cellulose ester to the polymer. The permeability of oleic acid was however unchanged, which is most probable a result of high solubility in the cellulose ester rich domains of the composites. Also, the following hypothesis is stated: cellulose stearate influence the polypropylene crystallization process by decreasing the size of spherulites.

  7. Characterization of acyl-ACP thioesterases of mangosteen (Garcinia mangostana) seed and high levels of stearate production in transgenic canola.

    PubMed

    Hawkins, D J; Kridl, J C

    1998-03-01

    Acyl-acyl-carrier protein (ACP) thioesterases are, at least in part, responsible for the fatty acyl chain length composition of seed storage oils. Acyl-ACP thioesterases with specificity for each of the saturated acyl-ACP substrates from 8:0 through 16:0 have been cloned, with the exception of 18:0, and are members of the FatB class of thioesterases. The authors have determined that the tropical tree species mangosteen (Garcinia mangostana) stores 18:0 (stearate) in its seed oil in amounts of up to 56% by weight. Acyl-ACP thioesterase activity as measured in crude mangosteen seed extracts showed a preference for 18:1-ACP substrates, but had significant activity with 18:0 relative to that with 16:0-ACP, suggesting a thioesterase might be involved in the production of stearate. Three distinct acyl-ACP thioesterases were cloned from mangosteen seed cDNA; two representative of the FatA class and one representative of the FatB class. When expressed in vitro, the enzyme encoded by one of the FatAs (Garm FatA1) while preferring 18:1-ACP showed relatively low activity with 16:0-ACP as compared to 18:0-ACP, similar to the substrate preferences shown by the crude seed extract. Expression of Garm FatA1 in Brassica seeds led to the accumulation of stearate up to 22% in seed oil. These results suggest that Garm FatA1 is at least partially responsible for determining the high stearate composition of mangosteen seed oil and that FatA as well FatB thioesterases have evolved for specialized roles.

  8. Analysis of magnesium from magnesium stearate in pharmaceutical tablet formulations using hydrophilic interaction liquid chromatography with nano quantity analyte detection.

    PubMed

    Risley, Donald S; Magnusson, Lars-Erik; Morow, Paul R; Aburub, Aktham

    2013-05-05

    This study demonstrates the use of hydrophilic interaction liquid chromatography with a nano quantity analyte detector for the retention, separation and detection of magnesium from magnesium stearate in tablet formulations for a drug product formulation blend containing a hydrochloride salt of a weakly basic compound as the active ingredient. The nano quantity analyte detector can provide direct detection of inactive excipients and inorganic salts lacking ultraviolet chromophores, as well as, all non-volatile compounds. The separation was accomplished using a SeQuant ZIC-HILIC column and mobile phase consisting of 32.5:32.5:35 of acetone/methanol/ammonium formate buffer (150 mM, pH 4.5). Common validation parameters were evaluated to assess the method's quantitative potential for magnesium (from magnesium stearate) including: linearity, accuracy, specificity, solution stability, repeatability, and intermediate precision. Overall, the method described in this report proved to be very robust and represents a novel technique to conveniently separate and detect magnesium from magnesium stearate in pharmaceutical preparations both quickly and accurately.

  9. Separating Octadecyltrimethoxysilane Hydrolysis and Condensation at the Air/Water Interface through Addition of Methyl Stearate

    PubMed Central

    Britt, David W.; Hlady, Vladimir

    2012-01-01

    The hydrolysis and condensation of octadecyltrimethoxysilane (OTMS) at the air/water interface were monitored through molecular area changes at a constant surface pressure of 10 mN/m. The onset of condensation was delayed through the addition of methyl stearate (SME) acting as an inert filler molecule. In the absence of SME, complete gelation of OTMS required 30 h, during which time OTMS condensation occurred concomitantly with hydrolysis. In the presence of SME, the OTMS monolayer gelation rate increased in proportion to the amount of SME present. A 1:6 OTMS:SME molar ratio resulted in monolayer gelation within 30 min, suggesting completion of monomer hydrolysis prior to condensation. These findings indicate that lability of OTMS to hydrolysis at the air/water interface is governed by steric and conformational constraints at the silicon atom site, with monomeric OTMS being much more reactive than oligomeric OTMS. Fluorescence microscope images demonstrated that the OTMS condensed domain size also decreased with increasing SME concentrations, further implicating SME’s role as an inert filler. PMID:25132807

  10. [Determination of magnesium stearate in pharmaceutical preparations using derivatization with 2-nitrophenylhydrazine and HPLC].

    PubMed

    Arai, Takashi; Hosoi, Yasue

    2005-03-01

    In general, spectrophotometric methods (inductively coupled plasma or atomic absorption spectrophotometry) are used for the assay of magnesium stearate (Mg-St). In this study, a new rapid, selective assay method was developed for Mg-St in pharmaceutical formulations. The method was based on isocratic reverse-phase liquid chromatography using a mobile phase of acetonitrile-water (80:20, v/v) after precolumn derivatization with 2-nitrophenyl hydrazine for sensitive UV detection. Margaric acid was used as an internal standard and the substances were detectable at 230 nm or 400 nm. Using a short (2 cm) HPLC column reduced the analytical time to 5 min. Validation of the newly developed method was performed in accordance with the International Conference on Harmonization guidelines. The linearity range for Mg-St was 0.00-0.04 mg/ml (as the concentration of injected sample solution) and their correlation factor was 0.9998. The determination and detection limits for Mg-St were 6 microg and 2 microg, respectively. The proposed method was successfully applied to the determination of trace amounts of Mg-St in commercially available tablets with a high recovery percentage, good accuracy, and precision.

  11. Mucoadhesive effect of thiolated PEG stearate and its modified NLC for ocular drug delivery.

    PubMed

    Shen, Jie; Wang, Yu; Ping, Qineng; Xiao, Yanyu; Huang, Xin

    2009-08-04

    This study was to develop a thiolated non-ionic surfactant, cysteine-polyethylene glycol stearate (Cys-PEG-SA), for the assembling of nanoparticulate ocular drug delivery system with mucoadhesive property. Cys-PEG-SA was synthesized in two steps reaction involving a new derivative intermediate formation of p-nitrophenylcarbonyl-PEG-SA (pNP-PEG-SA). Up to 369.43+/-25.54 mumol free thiol groups per gram of the conjugates was reached. The nanostructured lipid carrier (NLC) loaded cyclosporine A (CyA) was prepared by melt-emulsification method. The mucoadhesive NLC (Cys-NLC) was obtained by incubating NLC emulsion with Cys-PEG-SA. The mucoadhesive properties of these nanocarriers were examined by using mucin particles method. The particle size or zeta potential of the porcine mucin particles were changed with the added concentration of Cys-PEG-SA, and the disulphide bond breaker cysteine significantly reduced the adhesion of Cys-NLC to mucin particles (P<0.05), whereas PEG-SA and NLC did not alternate the properties of the mucin particles. When Cys-NLC was administered topically to the rabbit eye, the encapsulated cyclosporine was found to remain on the ocular surface in the cul-de-sac for up to 6 h, both precorneal retention time and concentration were dramatically increased (P<0.05), compared with the NLC without thiomer modification.

  12. Application and mechanism of inhalation profile improvement of DPI formulations by mechanofusion with magnesium stearate.

    PubMed

    Kumon, Michiko; Machida, Satoshi; Suzuki, Masahiko; Kusai, Akira; Yonemochi, Etsuo; Terada, Katsuhide

    2008-05-01

    In our previous paper, we reported the inhalation properties of dry powder inhaler (DPI) formulations containing Compound A and mechanofusion-processed lactose carriers. The mechanofusion process with magnesium stearate (Mg-St) on the lactose carrier enhanced the fine particle fraction (FPF) value of the Andersen cascade impactor (ACI) study. The increase of FPF seemed to be associated with the increase of the dispersibility of drug particles. The objectives of this study were (1) to evaluate the applicability of lactose carrier mechanofusion-processed with Mg-St and (2) to examine the mechanism of FPF alteration by the mechanofusion process applied on the lactose carrier with or without additive. The inhalation profiles of DPI formulations containing four different pharmaceutical compounds were evaluated with an ACI. The dispersibility of the formulations was observed by particle size distribution measurement in the air stream and the adhesive force was measured bydirect separation method. It was found that higher FPF was obtained with lactose mechanofusion-processed with Mg-St as compared to control lactose carriers for all four compounds. This suggested that mechanofusion process with Mg-St is widely applicable in DPI formulations. The homogenization of surface adhesiveness was attributed to the increased FPF of the DPI including lactose mechanofusion-processed with Mg-St, as suggested by the combination of several physicochemical characteristics. Combination of different characterization methods would be of help to clarify the whole mechanism which defines the inhalation properties of DPI formulations.

  13. Microstructure of calcium stearate matrix pellets: a function of the drying process.

    PubMed

    Schrank, Simone; Kann, Birthe; Windbergs, Maike; Glasser, Benjamin J; Zimmer, Andreas; Khinast, Johannes; Roblegg, Eva

    2013-11-01

    Drying is a common pharmaceutical process, whose potential to modify the final drug and/or dosage form properties is often underestimated. In the present study, pellets consisting of the matrix former calcium stearate (CaSt) incorporating the active pharmaceutical ingredient ibuprofen were prepared via wet extrusion and spheronization. Subsequent drying was performed by either desiccation, fluid-bed drying, or lyophilization, and the final pellets were compared with respect to their microstructure. To minimize the effect of solute ibuprofen molecules on the shrinking behavior of the CaSt, low ibuprofen loadings were used, as ibuprofen is soluble in the granulation liquid. Pellet porosity and specific surface area increased during desiccation, fluid-bed drying, and lyophilization. The inlet-air temperature during fluid-bed drying affected the specific surface area, which increased at lower inlet-air temperatures rather than the pellet porosity. The in vitro dissolution profiles were found to be a nonlinear function of the specific surface area. Overall, the microstructure, including porosity, pore size, and specific surface area, of CaSt pellets was a strong function of the drying conditions. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  14. Action of Humicola lanuginosa lipase on mixed monomolecular films of tricaprylin and polyethylene glycol stearate.

    PubMed

    Ivanova, Tz; Mircheva, K; Dobreva, G; Panaiotov, I; Proust, J E; Verger, R

    2008-05-01

    The hydrolysis catalyzed by Humicola lanuginosa lipase (HLL) of pure tricaprylin (TC) or stearate of polyethylene glycol 1500 (PEG-St) as well as their mixtures spread as monomolecular films were studied. The catalytic transformation of the two substrates TC or PEG-St into their respective reaction products was detected by measuring simultaneously the decrease in the film area and the surface potential using the "zero order" trough at constant surface pressure. A kinetic model describing the enzymatic hydrolysis was developed. The surface concentrations of the two substrates and their respective reaction products as well as the values of the global kinetic constants of hydrolysis were determined. The experimentally obtained global kinetic constants of the catalytic action of HLL against TC and PEG-St present in mixed monolayers of TC/PEG-St are approximately the same as in the case of pure monolayers. These obtained results give some indications that the activity of enzyme is not significantly affected by the different molecular environments in the mixed monolayers.

  15. The Protective Effects of 18β-Glycyrrhetinic Acid on Helicobacter pylori-Infected Gastric Mucosa in Mongolian Gerbils

    PubMed Central

    Cao, Donghui; Jiang, Jing; You, Lili; Jia, Zhifang; Tsukamoto, Tetsuya; Cai, Hongke; Wang, Shidong; Hou, Zhen; Suo, Yue-er; Cao, Xueyuan

    2016-01-01

    18β-Glycyrrhetinic acid (GRA), a major component of Glycyrrhiza glabra, is widely used therapeutically in clinic. In this study, the effect of GRA on Helicobacter pylori- (H. pylori-) infected gastritis was investigated in Mongolian gerbils in vivo. The gerbils were randomly divided into groups: uninfected; H. pylori-infected; H. pylori + antibiotics (clarithromycin, amoxicillin, and esomeprazole); and H. pylori + GRA. The gastric intraluminal pH value, histopathological changes, and the expression levels of inflammation-related cytokines (IL-1β, TNF-α, COX-2, and iNOS) were investigated. The results showed that, in the H. pylori + GRA group, the intraluminal gastric pH value was lower (2.14 ± 0.08 versus 3.17 ± 0.23, P < 0.05), erosion and hyperplasia were alleviated, the infiltration of neutrophils and mononuclear cells was attenuated (P < 0.05), and the expression levels of TNF-α, IL-1β, COX-2, and iNOS were decreased (P < 0.05) compared with the H. pylori-infected group. There was no significant difference in results between the H. pylori + GRA group and the H. pylori + antibiotics group. This study indicated that GRA significantly attenuated H. pylori-infected gastritis in gerbils and has the potential to be developed as a new therapeutic drug. PMID:27006947

  16. Synthesis, characterization and liver targeting evaluation of self-assembled hyaluronic acid nanoparticles functionalized with glycyrrhetinic acid.

    PubMed

    Wang, Xiaodan; Gu, Xiangqin; Wang, Huimin; Sun, Yujiao; Wu, Haiyang; Mao, Shirui

    2017-01-01

    Recently, polymeric materials with multiple functions have drawn great attention as the carrier for drug delivery system design. In this study, a series of multifunctional drug delivery carriers, hyaluronic acid (HA)-glycyrrhetinic acid (GA) succinate (HSG) copolymers were synthesized via hydroxyl group modification of hyaluronic acid. It was shown that the HSG nanoparticles had sub-spherical shape, and the particle size was in the range of 152.6-260.7nm depending on GA graft ratio. HSG nanoparticles presented good short term and dilution stability. MTT assay demonstrated all the copolymers presented no significant cytotoxicity. In vivo imaging analysis suggested HSG nanoparticles had superior liver targeting efficiency and the liver targeting capacity was GA graft ratio dependent. The accumulation of DiR (a lipophilic, NIR fluorescent cyanine dye)-loaded HSG-6, HSG-12, and HSG-20 nanoparticles in liver was 1.8-, 2.1-, and 2.9-fold higher than that of free DiR. The binding site of GA on HA may influence liver targeting efficiency. These results indicated that HSG copolymers based nanoparticles are potential drug carrier for improved liver targeting.

  17. In silico and in vivo anti-malarial studies of 18β glycyrrhetinic acid from Glycyrrhiza glabra.

    PubMed

    Kalani, Komal; Agarwal, Jyoti; Alam, Sarfaraz; Khan, Feroz; Pal, Anirban; Srivastava, Santosh Kumar

    2013-01-01

    Malaria is one of the most prevailing fatal diseases causing between 1.2 and 2.7 million deaths all over the world each year. Further, development of resistance against the frontline anti-malarial drugs has created an alarming situation, which requires intensive drug discovery to develop new, more effective, affordable and accessible anti-malarial agents possessing novel modes of action. Over the past few years triterpenoids from higher plants have shown a wide range of anti-malarial activities. As a part of our drug discovery program for anti-malarial agents from Indian medicinal plants, roots of Glycyrrhizaglabra were chemically investigated, which resulted in the isolation and characterization of 18β-glycyrrhetinic acid (GA) as a major constituent. The in vitro studies against P. falciparum showed significant (IC50 1.69 µg/ml) anti-malarial potential for GA. Similarly, the molecular docking studies showed adequate docking (LibDock) score of 71.18 for GA and 131.15 for standard anti-malarial drug chloroquine. Further, in silico pharmacokinetic and drug-likeness studies showed that GA possesses drug-like properties. Finally, in vivo evaluation showed a dose dependent anti-malarial activity ranging from 68-100% at doses of 62.5-250 mg/kg on day 8. To the best of our knowledge this is the first ever report on the anti-malarial potential of GA. Further work on optimization of the anti-malarial lead is under progress.

  18. Effects of oils and emulsifiers on the skin penetration of stearyl glycyrrhetinate in oil-in-water emulsions.

    PubMed

    Sakata, Osamu; Fujii, Makiko; Koizumi, Naoya; Nakade, Masato; Kameyama, Koichi; Watanabe, Yoshiteru

    2014-01-01

    We investigated whether an emulsifier or an emulsified oil affects the skin penetration of stearyl glycyrrhetinate (SG) when it is applied in an oil-in-water (O/W)-type emulsion under finite dose conditions in vitro. SG has a high molecular weight (MW: 723) and high lipophilicity (log P: 15.6). Skin penetration of SG applied with O/W emulsions was evaluated using 6 types of emulsifiers that are commonly used in cosmetics; however, no significant differences were observed between these emulsifiers. When applied with liquid paraffins in oil phase, SG skin penetration increased significantly as the molecular weight of the liquid paraffin decreased. The skin penetration of the fluorescent dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI; MW: 834, log P: 23.2) also increased with O/W-type emulsions containing liquid paraffins of lower molecular weights. These results indicate that use of O/W-type emulsions with an appropriate oil phase can improve SG skin penetration.

  19. One-step Conjugation of Glycyrrhetinic Acid to Cationic Polymers for High-performance Gene Delivery to Cultured Liver Cell.

    PubMed

    Cong, Yue; Shi, Bingyang; Lu, Yiqing; Wen, Shihui; Chung, Roger; Jin, Dayong

    2016-02-23

    Gene therapies represent a promising therapeutic route for liver cancers, but major challenges remain in the design of safe and efficient gene-targeting delivery systems. For example, cationic polymers show good transfection efficiency as gene carriers, but are hindered by cytotoxicity and non-specific targeting. Here we report a versatile method of one-step conjugation of glycyrrhetinic acid (GA) to reduce cytotoxicity and improve the cultured liver cell -targeting capability of cationic polymers. We have explored a series of cationic polymer derivatives by coupling different ratios of GA to polypropylenimine (PPI) dendrimer. These new gene carriers (GA-PPI dendrimer) were systematically characterized by UV-vis,(1)H NMR titration, electron microscopy, zeta potential, dynamic light-scattering, gel electrophoresis, confocal microscopy and flow cytometry. We demonstrate that GA-PPI dendrimers can efficiently load and protect pDNA, via formation of nanostructured GA-PPI/pDNA polyplexes. With optimal GA substitution degree (6.31%), GA-PPI dendrimers deliver higher liver cell transfection efficiency (43.5% vs 22.3%) and lower cytotoxicity (94.3% vs 62.5%, cell viability) than the commercial bench-mark DNA carrier bPEI (25 kDa) with cultured liver model cells (HepG2). There results suggest that our new GA-PPI dendrimer are a promising candidate gene carrier for targeted liver cancer therapy.

  20. One-step Conjugation of Glycyrrhetinic Acid to Cationic Polymers for High-performance Gene Delivery to Cultured Liver Cell

    PubMed Central

    Cong, Yue; Shi, Bingyang; Lu, Yiqing; Wen, Shihui; Chung, Roger; Jin, Dayong

    2016-01-01

    Gene therapies represent a promising therapeutic route for liver cancers, but major challenges remain in the design of safe and efficient gene-targeting delivery systems. For example, cationic polymers show good transfection efficiency as gene carriers, but are hindered by cytotoxicity and non-specific targeting. Here we report a versatile method of one-step conjugation of glycyrrhetinic acid (GA) to reduce cytotoxicity and improve the cultured liver cell -targeting capability of cationic polymers. We have explored a series of cationic polymer derivatives by coupling different ratios of GA to polypropylenimine (PPI) dendrimer. These new gene carriers (GA-PPI dendrimer) were systematically characterized by UV-vis,1H NMR titration, electron microscopy, zeta potential, dynamic light-scattering, gel electrophoresis, confocal microscopy and flow cytometry. We demonstrate that GA-PPI dendrimers can efficiently load and protect pDNA, via formation of nanostructured GA-PPI/pDNA polyplexes. With optimal GA substitution degree (6.31%), GA-PPI dendrimers deliver higher liver cell transfection efficiency (43.5% vs 22.3%) and lower cytotoxicity (94.3% vs 62.5%, cell viability) than the commercial bench-mark DNA carrier bPEI (25kDa) with cultured liver model cells (HepG2). There results suggest that our new GA-PPI dendrimer are a promising candidate gene carrier for targeted liver cancer therapy. PMID:26902258

  1. Lubrication potential of magnesium stearate studied on instrumented rotary tablet press.

    PubMed

    Patel, Sarsvatkumar; Kaushal, Aditya Mohan; Bansal, Arvind Kumar

    2007-10-26

    The aim of this study was to investigate the lubrication potential of 2 grades of magnesium stearate (MS) blended with a mix of dicalcium phosphate dihydrate and microcrystalline cellulose. Force-displacement, force-time, and ejection profiles were generated using an instrumented rotary tablet press, and the effect of MS mixing time (10, 20, and 30 minutes) and tableting speed (10.7, 13.8, and 17.5 rpm) was investigated. The packing index (PI), frictional index (FI), and packing energy (PE) derived from the force-displacement profiles showed that MS sample I performed better than sample II. At higher lubricant mixing times, the values of PI were observed to increase, and values of FI and PE were observed to decrease for both MS samples. Lower values of area under the curve (AUC) calculated from force-time compression profiles also showed sample I to be superior to sample II in lubrication potential. For both the samples, the values of AUC were observed to decrease with higher lubricant mixing times. Tapping volumetry that simulates the initial particle rearrangement gave values of parameter a and C(max) that were higher for sample I than sample II and also increased with lubricant mixing time. The superior lubrication potential of sample I was also established by the lower values of peak ejection force encountered in the ejection profile. Lower ejection forces were also found to result from higher tableting speeds and longer lubricant mixing times. The difference in lubrication efficacy of the 2 samples could be attributed to differences in their solid-state properties, such as particle size, specific surface area, and d-spacing.

  2. PEG-stearate coated solid lipid nanoparticles as levothyroxine carriers for oral administration

    NASA Astrophysics Data System (ADS)

    Kashanian, Soheila; Rostami, Elham

    2014-03-01

    In this study, poly ethylene glycol 100 stearate (PEG 100-S) was used to prepare coated solid lipid nanoparticles with loading levothyroxine sodium (levo-loaded PEG 100-S-coated SLNs) by microemulsification technique. Evaluation of the release kinetic of prepared colloidal carriers was conducted. The particle size and zeta potential of levo-loaded PEG 100-S-coated SLNs have been measured to be 187.5 nm and -23.0 mV, respectively, using photon correlation spectroscopy (PCS). Drug entrapment efficiency (EE) was calculated to be 99 %. Differential scanning calorimetry indicated that the majority of drug loaded in PEG 100-S-coated SLNs were in amorphous state which could be considered desirable for drug delivery. The purpose of this study was to develop a new nanoparticle system, consisting lipid nanoparticles coated with PEG 100-S. The modification procedure led to a reduction in the zeta potential values, varying from -40.0 to -23.0 mV for the uncoated and PEG-coated SLNs, respectively. Stability results of the nanoparticles in gastric and intestinal media show that the low pH of the gastric medium is responsible for the critical aggregation and degradation of the uncoated lipid nanoparticles. PEG 100-S-coated SLNs were more stable due to their polymer coating layer which prevented aggregation of SLNs. Consequently, it is possible that the PEG surrounds the particles reducing the attachment of enzymes and further degradation of the triglyceride cores. Shape and surface morphology of particles were determined by transition electron microscopy and scanning electron microscopy that revealed spherical shape of nanoparticles. In vitro drug release of PEG 100-S-coated SLNs was characterized using diffusion cell which showed a controlled release for drug.

  3. Development of sustained-release lipophilic calcium stearate pellets via hot melt extrusion.

    PubMed

    Roblegg, Eva; Jäger, Evelyn; Hodzic, Aden; Koscher, Gerold; Mohr, Stefan; Zimmer, Andreas; Khinast, Johannes

    2011-11-01

    The objective of this study was the development of retarded release pellets using vegetable calcium stearate (CaSt) as a thermoplastic excipient. The matrix carrier was hot melt extruded and pelletized with a hot-strand cutter in a one step continuous process. Vegetable CaSt was extruded at temperatures between 100 and 130°C, since at these temperatures cutable extrudates with a suitable melt viscosity may be obtained. Pellets with a drug loading of 20% paracetamol released 11.54% of the drug after 8h due to the great densification of the pellets. As expected, the drug release was influenced by the pellet size and the drug loading. To increase the release rate, functional additives were necessary. Therefore, two plasticizers including glyceryl monostearate (GMS) and tributyl citrate (TBC) were investigated for plasticization efficiency and impact on the in vitro drug release. GMS increased the release rate due to the formation of pores at the surface (after dissolution) and showed no influence on the process parameters. The addition of TBC increased the drug release to a higher extent. After dissolving, the pellets exhibited pores at the surface and in the inner layer. Small- and Wide-Angle X-ray Scattering (SWAXS) revealed no major change in crystalline peaks. The results demonstrated that (nearly) spherical CaSt pellets could be successfully prepared by hot melt extrusion using a hot-strand cutter as downstreaming system. Paracetamol did not melt during the process indicating a solid suspension. Due to the addition of plasticizers, the in vitro release rate could be tailored as desired.

  4. Semi-solid Sucrose Stearate-Based Emulsions as Dermal Drug Delivery Systems

    PubMed Central

    Klang, Victoria; Schwarz, Julia C.; Matsko, Nadejda; Rezvani, Elham; El-Hagin, Nivine; Wirth, Michael; Valenta, Claudia

    2011-01-01

    Mild non-ionic sucrose ester surfactants can be employed to produce lipid-based drug delivery systems for dermal application. Moreover, sucrose esters of intermediate lipophilicity such as sucrose stearate S-970 possess a peculiar rheological behavior which can be employed to create highly viscous semi-solid formulations without any further additives. Interestingly, it was possible to develop both viscous macroemulsions and fluid nanoemulsions with the same chemical composition merely by slight alteration of the production process. Optical light microscopy and cryo transmission electron microscopy (TEM) revealed that the sucrose ester led to the formation of an astonishing hydrophilic network at a concentration of only 5% w/w in the macroemulsion system. A small number of more finely structured aggregates composed of surplus surfactant were likewise detected in the nanoemulsions. These discoveries offer interesting possibilities to adapt the low viscosity of fluid O/W nanoemulsions for a more convenient application. Moreover, a simple and rapid production method for skin-friendly creamy O/W emulsions with excellent visual long-term stability is presented. It could be shown by franz-cell diffusion studies and in vitro tape stripping that the microviscosity within the semi-solid formulations was apparently not influenced by their increased macroviscosity: the release of three model drugs was not impaired by the complex network-like internal structure of the macroemulsions. These results indicate that the developed semi-solid emulsions with advantageous application properties are highly suitable for the unhindered delivery of lipophilic drugs despite their comparatively large particle size and high viscosity. PMID:24310496

  5. Chromolithic method development, validation and system suitability analysis of ultra-sound assisted extraction of glycyrrhizic acid and glycyrrhetinic acid from Glycyrrhiza glabra.

    PubMed

    Gupta, Suphla; Sharma, Rajni; Pandotra, Pankaj; Jaglan, Sundeep; Gupta, Ajai Prakash

    2012-08-01

    An ultrasound-assisted extraction and chromolithic LC method was developed for simultaneous determination of glycyrrhizic acid (GA) and glycyrrhetinic acid (GL) from the root extract of Glycyrrhizza glabra using RPLC-PDA. The developed method was validated according to the International Conference on Harmonisation. The method exhibited good linearity (r2 > 0.9989) with high precision and achieved good accuracies between 97.5 to 101.3% of quantitative results. The method is more sensitive and faster (resolved within ten minutes) than the earlier developed methods using normal LC columns.

  6. A novel 18 beta-glycyrrhetinic acid analogue as a potent and selective inhibitor of 11 beta-hydroxysteroid dehydrogenase 2.

    PubMed

    Vicker, Nigel; Su, Xiangdong; Lawrence, Harshani; Cruttenden, Adrian; Purohit, Atul; Reed, Michael J; Potter, Barry V L

    2004-06-21

    Using 18beta-glycyrrhetinic acid as a template, the synthesis of a series of secondary amides at the 30-position is described and the effects of these modifications on the SAR of the 11beta-hydroxysteroid dehydrogenase isozymes type 1 and 2 from the rat are investigated. An isoform selective inhibitor has been discovered and compound 5, N-(2-hydroxyethyl)-3beta-hydroxy-11-oxo-18beta-olean-12-en-30-oic acid amide, is highlighted as a very potent and selective inhibitor of 11beta-hydroxysteroid dehydrogenase 2 with an IC(50)=4 pM.

  7. Synthesis of novel 2-cyano substituted glycyrrhetinic acid derivatives as inhibitors of cancer cells growth and NO production in LPS-activated J-774 cells.

    PubMed

    Salomatina, Oksana V; Markov, Andrey V; Logashenko, Evgeniya B; Korchagina, Dina V; Zenkova, Marina A; Salakhutdinov, Nariman F; Vlassov, Valentin V; Tolstikov, Genrikh A

    2014-01-01

    Here we report the synthesis and biological activity of new semi-synthetic derivatives of naturally occurring glycyrrhetinic acid bearing a 2-cyano-3-oxo-1-en moiety in the A-ring and double bonds and carbonyl groups in the C, D and E rings. Bioassays using murine macrophage-like and tumor cells show that compound 4, which differs from Soloxolone methyl by the absence of a 9(11)-double bond in the C-ring, displays anti-inflammatory and inhibitory activities with respect to tumor cells with a high selectivity index value. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Metal stearate distributions in modern artists' oil paints: surface and cross-sectional investigation of reference paint films using conventional and synchrotron infrared microspectroscopy.

    PubMed

    Osmond, Gillian; Boon, Jaap J; Puskar, Ljiljana; Drennan, John

    2012-10-01

    Zinc oxide is a prevalent industrial-age pigment that readily reacts with fatty acids in oil-based paints to form zinc carboxylates. Zinc stearate aggregates are associated with deterioration in late nineteenth and twentieth century paintings. The current study uses both conventional and synchrotron Fourier transform infrared spectroscopy (FT-IR) to investigate metal carboxylate composition in a range of naturally aged artists' oil paints and reference paint film draw-downs. The paints contain zinc oxide alone or in combination with lead white, titanium white, and aluminum stearate and are prepared with linseed and safflower oils. Attenuated total reflectance (ATR)-FT-IR using the conventional source identifies marked differences in carboxylate profiles between exposed and protected surfaces in a large number of samples. Synchrotron FT-IR microspectroscopy of thin paint cross-sections maps metal carboxylate distributions at high spatial resolution and resolves broad concentration gradients and micrometer-scale phase separation of carboxylate species. Aluminum stearate, a common paint additive, is found to influence the distribution of zinc carboxylates more strongly than pigment composition or oil type. The presence of aluminum stearate results in higher concentrations and more pronounced separation of saturated C16 and C18 chain zinc carboxylates in the margin of paint nearest the polyester substrate. The presence of aluminum stearate in association with zinc oxide has a clear influence on zinc carboxylate formation and distribution, with potential implications for long term stability of vulnerable paintings.

  9. Preparation, characterization and in vitro activities evaluation of solid lipid nanoparticles based on PEG-40 stearate for antifungal drugs vaginal delivery.

    PubMed

    Cassano, Roberta; Ferrarelli, Teresa; Mauro, Maria Vittoria; Cavalcanti, Paolina; Picci, Nevio; Trombino, Sonia

    2016-01-01

    The present article reports the preparation, characterization and performance evaluation of solid lipid nanoparticles (SLNs) based on polyoxyethylene-40 stearate (PEG-40 stearate) for the administration of antifungal agents such as ketoconazole and clotrimazole. These nanoparticles could be useful in the treatment of vaginal infections sustained by Candida albicans. In particular, PEG-40 stearate was made to react with acryloyl chloride in order to introduce an easily polymerizable moiety for the creation of a second shell and to ensure a slow drug release. In addition, the differences on the release profiles between PEG-40 stearate-based nanoparticles, PEG-40 stearate acrylate based and polymerized ones, were analyzed under conditions, simulating the typical environment of Candida albicans infection. Then, the antifungal activity of nanoparticles was also evaluated in terms of minimal inhibitory concentration. Moreover, the nanoparticles were submitted to in vitro studies for evaluating the drug permeability at the site of action. Results indicated that the obtained particles are potentially useful for the treatment of vaginal infections sustained by Candida albicans.

  10. 18β-Glycyrrhetinic Acid Suppresses Cell Proliferation through Inhibiting Thromboxane Synthase in Non-Small Cell Lung Cancer

    PubMed Central

    Huang, Qing-Chun; Chen, Xiu-Min; Jiang, Ze-Bo; Zhang, Xian; Zeng, Xing

    2014-01-01

    18β-glycyrrhetinic acid (18β-GA) is a bioactive component of licorice. The anti-cancer activity of 18β-GA has been studied in many cancer types, whereas its effects in lung cancer remain largely unknown. We first showed that 18β-GA effectively suppressed cell proliferation and inhibited expression as well as activity of thromboxane synthase (TxAS) in non-small cell lung cancer (NSCLC) cells A549 and NCI-H460. In addition, the administration of 18β-GA did not have any additional inhibitory effect on the decrease of cell proliferation induced by transfection with TxAS small interference RNA (siRNA). Moreover, 18β-GA failed to inhibit cell proliferation in the immortalized human bronchial epithelial cells 16HBE-T and another NSCLC cell line NCI-H23, both of which expressed minimal level of TxAS as compared to A549 and NCI-H460. However, 18β-GA abolished the enhancement of cell proliferation induced by transfection of NCI-H23 with pCMV6-TxAS plasmid. Further study found that the activation of both extracellular signal-regulated kinase (ERK)1/2 and cyclic adenosine monophosphate response element binding protein (CREB) induced by TxAS cDNA transfection could be totally blocked by 18β-GA. Altogether, we have delineated that, through inhibiting TxAS and its initiated ERK/CREB signaling, 18β-GA suppresses NSCLC cell proliferation. Our study has highlighted the significance of 18β-GA with respect to prevention and treatment of NSCLC. PMID:24695790

  11. Inhibition of human and rat 11beta-hydroxysteroid dehydrogenase type 1 by 18beta-glycyrrhetinic acid derivatives.

    PubMed

    Su, Xiangdong; Vicker, Nigel; Lawrence, Harshani; Smith, Andrew; Purohit, Atul; Reed, Michael J; Potter, Barry V L

    2007-05-01

    11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) plays an important role in regulating the cortisol availability to bind to corticosteroid receptors within specific tissue. Recent advances in understanding the molecular mechanisms of metabolic syndrome indicate that elevation of cortisol levels within specific tissues through the action of 11beta-HSD1 could contribute to the pathogenesis of this disease. Therefore, selective inhibitors of 11beta-HSD1 have been investigated as potential treatments for metabolic diseases, such as diabetes mellitus type 2 or obesity. Here we report the discovery and synthesis of some 18beta-glycyrrhetinic acid (18beta-GA) derivatives (2-5) and their inhibitory activities against rat hepatic11beta-HSD1 and rat renal 11beta-HSD2. Once the selectivity over the rat type 2 enzyme was established, these compounds' ability to inhibit human 11beta-HSD1 was also evaluated using both radioimmunoassay (RIA) and homogeneous time resolved fluorescence (HTRF) methods. The 11-modified 18beta-GA derivatives 2 and 3 with apparent selectivity for rat 11beta-HSD1 showed a high percentage inhibition for human microsomal 11beta-HSD1 at 10 microM and exhibited IC50 values of 400 and 1100 nM, respectively. The side chain modified 18beta-GA derivatives 4 and 5, although showing selectivity for rat 11beta-HSD1 inhibited human microsomal 11beta-HSD1 with IC50 values in the low micromolar range.

  12. Synthesis, characterization, and in vitro evaluation of curcumin-loaded albumin nanoparticles surface-functionalized with glycyrrhetinic acid

    PubMed Central

    Li, Jingjing; Chen, Tong; Deng, Feng; Wan, Jingyuan; Tang, Yalan; Yuan, Pei; Zhang, Liangke

    2015-01-01

    We have designed and developed curcumin (Ccn)-loaded albumin nanoparticles (BNPs) surface-functionalized with glycyrrhetinic acid (Ccn-BNP-GA) for GA receptor-mediated targeting. Ccn-BNP-GA was prepared by conjugating GA as a hepatoma cell-specific binding molecule onto the surface of BNPs. Ccn-BNP-GA showed a narrow distribution with an average size of 258.8±6.4 nm, a regularly spherical shape, an entrapment efficiency of 88.55%±5.54%, and drug loading of 25.30%±1.58%. The density of GA as the ligand conjugated to BNPs was 140.48±2.784 μg/g bovine serum albumin. Cytotoxicity assay results indicated that Ccn-BNP-GA was significantly more cytotoxic to HepG2 cells and in a concentration-dependent manner. Ccn-BNP-GA also appeared to be taken up to a greater extent by HepG2 cells than undecorated groups, which might be due to the high affinity of GA for GA receptors on the HepG2 cell surface. These cytotoxicity assay results were corroborated by analysis of cell apoptosis and the cell cycle. Further, Ccn-BNP-GA showed an approximately twofold higher rate of cell apoptosis than the other groups. Moreover, proliferation of HepG2 cells was arrested in G2/M phase based on cell cycle analysis. These results, which were supported by the GA receptor-mediated endocytosis mechanism, indicate that BNPs surface-functionalized with GA could be used in targeted cancer treatment with high efficacy, sufficient targeting, and reduced toxicity. PMID:26346750

  13. 18α-Glycyrrhetinic Acid Proteasome Activator Decelerates Aging and Alzheimer's Disease Progression in Caenorhabditis elegans and Neuronal Cultures

    PubMed Central

    Papaevgeniou, Nikoletta; Sakellari, Marianthi; Jha, Sweta; Tavernarakis, Nektarios; Holmberg, Carina I.; Gonos, Efstathios S.

    2016-01-01

    Abstract Aims: Proteasomes are constituents of the cellular proteolytic networks that maintain protein homeostasis through regulated proteolysis of normal and abnormal (in any way) proteins. Genetically mediated proteasome activation in multicellular organisms has been shown to promote longevity and to exert protein antiaggregation activity. In this study, we investigate whether compound-mediated proteasome activation is feasible in a multicellular organism and we dissect the effects of such approach in aging and Alzheimer's disease (AD) progression. Results: Feeding of wild-type Caenorhabditis elegans with 18α-glycyrrhetinic acid (18α-GA; a previously shown proteasome activator in cell culture) results in enhanced levels of proteasome activities that lead to a skinhead-1- and proteasome activation-dependent life span extension. The elevated proteasome function confers lower paralysis rates in various AD nematode models accompanied by decreased Aβ deposits, thus ultimately decelerating the progression of AD phenotype. More importantly, similar positive results are also delivered when human and murine cells of nervous origin are subjected to 18α-GA treatment. Innovation: This is the first report of the use of 18α-GA, a diet-derived compound as prolongevity and antiaggregation factor in the context of a multicellular organism. Conclusion: Our results suggest that proteasome activation with downstream positive outcomes on aging and AD, an aggregation-related disease, is feasible in a nongenetic manipulation manner in a multicellular organism. Moreover, they unveil the need for identification of antiaging and antiamyloidogenic compounds among the nutrients found in our normal diet. Antioxid. Redox Signal. 25, 855–869. PMID:26886723

  14. 18ß-glycyrrhetinic acid derivative promotes proliferation, migration and aquaporin-3 expression in human dermal fibroblasts.

    PubMed

    Hung, Chi-Feng; Hsiao, Chien-Yu; Hsieh, Wen-Hao; Li, Hsin-Ju; Tsai, Yi-Ju; Lin, Chun-Nan; Chang, Hsun-Hsien; Wu, Nan-Lin

    2017-01-01

    Licorice (Glycyrrhiza) species have been widely used as a traditional medicine and a natural sweetener in foods. The 18β-glycyrrhetinic acid (18β-GA) is a bioactive compound in licorice that exhibits potential anti-cancer, anti-inflammatory, and anti-microbial activities. Many synthesized derivatives of 18β-GA have been reported to be cytotoxic and suggested for the treatment of malignant diseases. In this study, we explored the possible pharmacological roles of an 18β-GA derivative in skin biology using primary human dermal fibroblasts and HaCaT keratinocytes as cell models. We found that this 18β-GA derivative did not cause cell death, but significantly enhanced the proliferation of dermal fibroblasts and HaCaT keratinocytes. A scratch wound healing assay revealed that the 18β-GA derivative promoted the migration of fibroblasts. Due to the important role of aquaporin-3 in cell migration and proliferation, we also investigated the expression of aquaporin-3 and found this compound up-regulated the expression of aquaporin-3 in dermal fibroblasts and HaCaT keratinocytes. In dermal fibroblasts, the 18β-GA derivative induced the phosphorylation of Akt, ERK, and p38. The inhibitor of Akt predominantly suppressed the 18β-GA derivative-induced expression of aquaporin-3. Collectively, this compound had a positive effect on the proliferation, migration, and aquaporin-3 expression of skin cells, implying its potential role in the treatment of skin diseases characterized by impaired wound healing or dermal defects.

  15. In Vitro and in Vivo Inhibitory Effects of Glycyrrhetinic Acid in Mice and Human Cytochrome P450 3A4.

    PubMed

    Lv, Qiao-Li; Wang, Gui-Hua; Chen, Shu-Hui; Hu, Lei; Zhang, Xue; Ying, Guo; Qin, Chong-Zhen; Zhou, Hong-Hao

    2015-12-25

    Glycyrrhetinic acid (GA) has been used clinically in the treatment of patients with chronic hepatitis. This study evaluated the effect of GA on the activity of five P450(CYP450) cytochrome enzymes: CYP2A6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, in human liver microsomes (HLMs) and recombinant cDNA-expressed enzyme systems using a HPLC-MS/MS CYP-specific probe substrate assay. With midazolam as the probe substrate, GA greatly decreased CYP3A4 activity with IC50 values of 8.195 μM in HLMs and 7.498 μM in the recombinant cDNA-expressed CYP3A4 enzyme system, respectively. It significantly decreased CYP3A4 activity in a dose- but not time-dependent manner. Results from Lineweaver-Burk plots showed that GA could inhibit CYP3A4 activity competitively, with a Ki value of 1.57 μM in HLMs. Moreover, CYP2C9 and CYP2C19 could also be inhibited significantly by GA with IC50 of 42.89 and 40.26 μM in HLMs, respectively. Other CYP450 isoforms were not markedly affected by GA. The inhibition was also confirmed by an in vivo study of mice. In addition, it was observed that mRNA expressions of the Cyps2c and 3a family decreased significantly in the livers of mice treated with GA. In conclusion, this study indicates that GA may exert herb-drug interactions by competitively inhibiting CYP3A4.

  16. Increasing the stearate content in seed oil of Brassica juncea by heterologous expression of MlFatB affects lipid content and germination frequency of transgenic seeds.

    PubMed

    Bhattacharya, Surajit; Sinha, Saheli; Das, Natasha; Maiti, Mrinal K

    2015-11-01

    Fatty acids from dietary lipids can impart both beneficial and harmful health effects. The compositional balance between saturated and unsaturated fatty acids plays a decisive role in maintaining the physiological harmony, proper growth and development in the human system. In case of Brassica juncea seed oil, the level of saturated fatty acid, especially desirable stearate is very much lower than the recommended value, along with a high content of nutritionally undesirable erucic acid. Therefore, in order to shift the carbon flux towards the production of stearate at the expense of erucate, the MlFatB gene encoding a FatB thioesterase from Madhuca longifolia (latifolia) was expressed heterologously in seed tissues of B. juncea. The functional MlFatB competed with the highly active endogenous BjFatA thioesterase, and the transgenic B. juncea lines showed noteworthy changes in their seed fatty acid profiles. The proportion of stearate increased up to 16-fold, constituting almost 31% of the total fatty acids along with the production of arachidic acid in significant amount (up to ∼11%). Moreover, the content of erucate was reduced up to 71% in the seed oils of transgenic lines. Although a nutritionally desirable fatty acid profile was achieved, the transgenic seeds exhibit reduction or abolition of seed germination in addition to a decrease in seed lipid content. The findings of the present study revealing the stearoyl-ACP thioesterase-mediated enhancement of the stearate content that is associated with reduced germination frequency of transgenic B. juncea seeds, may explain why no natural or induced stearate-rich Brassica has been found or developed. Furthermore, this study also suggests that the newly characterized MlFatB is a potential candidate gene for refined metabolic engineering strategy in B. juncea or other plant species for increasing stearate content in seed oil. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  17. Synthesis of glycyrrhetinic acid-modified chitosan 5-fluorouracil nanoparticles and its inhibition of liver cancer characteristics in vitro and in vivo.

    PubMed

    Cheng, Mingrong; Gao, Xiaoyan; Wang, Yong; Chen, Houxiang; He, Bing; Xu, Hongzhi; Li, Yingchun; Han, Jiang; Zhang, Zhiping

    2013-09-17

    Nanoparticle drug delivery (NDDS) is a novel system in which the drugs are delivered to the site of action by small particles in the nanometer range. Natural or synthetic polymers are used as vectors in NDDS, as they provide targeted, sustained release and biodegradability. Here, we used the chitosan and hepatoma cell-specific binding molecule, glycyrrhetinic acid (GA), to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by Fourier transformed infrared spectroscopy (FT-IR) and ¹H-nuclear magnetic resonance (¹H-NMR). By combining GA-CTS and 5-FU (5-fluorouracil), we obtained a GA-CTS/5-FU nanoparticle, with a particle size of 217.2 nm, a drug loading of 1.56% and a polydispersity index of 0.003. The GA-CTS/5-FU nanoparticle provided a sustained release system comprising three distinct phases of quick, steady and slow release. We demonstrated that the nanoparticle accumulated in the liver. In vitro data indicated that it had a dose- and time-dependent anti-cancer effect. The effective drug exposure time against hepatic cancer cells was increased in comparison with that observed with 5-FU. Additionally, GA-CTS/5-FU significantly inhibited the growth of drug-resistant hepatoma, which may compensate for the drug-resistance of 5-FU. In vivo studies on an orthotropic liver cancer mouse model demonstrated that GA-CTS/5-FU significantly inhibited tumor growth, resulting in increased survival time.

  18. Synthesis of novel 3-amino and 29-hydroxamic acid derivatives of glycyrrhetinic acid as selective 11β-hydroxysteroid dehydrogenase 2 inhibitors.

    PubMed

    Stanetty, Christian; Czollner, Laszlo; Koller, Iris; Shah, Priti; Gaware, Rawindra; Cunha, Thierry Da; Odermatt, Alex; Jordis, Ulrich; Kosma, Paul; Classen-Houben, Dirk

    2010-11-01

    Glycyrrhetinic acid, the metabolite of the natural product glycyrrhizin, is a well known nonselective inhibitor of 11β-hydroxysteroid dehydrogenase (11β-HSD) type 1 and type 2. Whereas inhibition of 11β-HSD1 is currently under consideration for treatment of metabolic diseases, such as obesity and diabetes, 11β-HSD2 inhibitors may find therapeutic applications in chronic inflammatory diseases and certain forms of cancer. So far, no selective 11β-HSD2 inhibitor has been developed and neither animal studies nor clinical trials have been reported based on 11β-HSD2 inhibition. Starting from the lead compound glycyrrhetinic acid, novel triterpene type derivatives were synthesized and analyzed for their biological activity against overexpressed human 11β-HSD1 and 11β-HSD2 in cell lysates. Several hydroxamic acid derivatives showed high selectivity for 11β-HSD2. The most potent and selective compound is active against human 11β-HSD2 in the low nanomolar range with a 350-fold selectivity over human 11β-HSD1.

  19. Design, synthesis and in vitro evaluation of 18β-glycyrrhetinic acid derivatives for anticancer activity against human breast cancer cell line MCF-7.

    PubMed

    Yadav, Dharmendra Kumar; Kalani, Komal; Singh, Abhishek K; Khan, Feroz; Srivastava, Santosh K; Pant, Aditya B

    2014-01-01

    In the present work, QSAR model was derived by multiple linear regression method for the prediction of anticancer activity of 18β-glycyrrhetinic acid derivatives against the human breast cancer cell line MCF-7. The QSAR model for anti-proliferative activity against MCF-7 showed high correlation (r(2)=0.90 and rCV(2)=0.83) and indicated that chemical descriptors namely, dipole moment (debye), steric energy (kcal/mole), heat of formation (kcal/mole), ionization potential (eV), LogP, LUMO energy (eV) and shape index (basic kappa, order 3) correlate well with activity. The QSAR virtually predicted that active derivatives were first semi-synthesized and characterized on the basis of their (1)H and (13)C NMR spectroscopic data and then were in-vitro tested against MCF-7 cancer cell line. In particular, octylamide derivative of glycyrrhetinic acid GA-12 has marked cytotoxic activity against MCF-7 similar to that of standard anticancer drug paclitaxel. The biological assays of active derivative selected by virtual screening showed significant experimental activity.

  20. Ethanol diversely alters palmitate, stearate and oleate metabolism in the liver and pancreas of rats using the deuterium oxide single tracer

    PubMed Central

    Boros, Laszlo G.; Deng, Qinggao; Pandol, Stephen J.; Tsukamoto, Hidekazu; Go, Vay Liang W.; Lee, Wai-Nang Paul

    2015-01-01

    Objective To determine tissue specific effects of alcohol on fatty acid synthesis and distribution as related to functional changes in triglyceride transport and membrane formation. Methods Tissue fatty acid profile, and de novo lipogenesis were determined in adult male Wistar rats after 5 weeks of ethanol feeding using deuterated water and GC/MS. Liver and pancreas fatty acid profiles and new synthesis fractions were compared with those from control rats on an isocaloric diet. Results Fatty acid ratios in the liver indicated that there was an over two-fold accumulation of stearate to that of palmitate, with an apparent decrease in oleate content. On the other hand, in the pancreas there was a 17% decrease in the stearate to palmitate ratio, while oleate to palmitate ratio was increased by 30%. The fractions of deuterium labeled palmitate and stearate were substantially reduced in the liver and pancreas of the alcohol treated animals. Deuterium labeling of oleate was reduced in the liver but not in the pancreas consistent with the oleate/stearate ratios in these tissues. Conclusions Long-term alcohol exposure results in opposite effects on the desaturase activity in the liver and pancreas limiting fatty acid transport in the liver but promoting the exocrine function of the pancreas. PMID:19248221

  1. Ethanol diversely alters palmitate, stearate, and oleate metabolism in the liver and pancreas of rats using the deuterium oxide single tracer.

    PubMed

    Boros, Laszlo G; Deng, Qinggao; Pandol, Stephen J; Tsukamoto, Hidekazu; Go, Vay Liang W; Lee, Wai-Nang Paul

    2009-03-01

    To determine tissue-specific effects of alcohol on fatty acid synthesis and distribution as related to functional changes in triglyceride transport and membrane formation. Tissue fatty acid profile and de novo lipogenesis were determined in adult male Wistar rats after 5 weeks of ethanol feeding using deuterated water and gas chromatography/mass spectrometry. Liver and pancreas fatty acid profiles and new synthesis fractions were compared with those from control rats on an isocaloric diet. Fatty acid ratios in the liver indicated that there was a more than 2-fold accumulation of stearate to that of palmitate, with an apparent decrease in oleate content. On the other hand, in the pancreas, there was a 17% decrease in the stearate-to-palmitate ratio, whereas the oleate-to-palmitate ratio was increased by 30%. The fractions of deuterium-labeled palmitate and stearate were substantially reduced in the liver and pancreas of the alcohol-treated animals. Deuterium labeling of oleate was reduced in the liver but not in the pancreas, consistent with the oleate/stearate ratios in these tissues. Long-term alcohol exposure results in opposite effects on the desaturase activity in the liver and pancreas, limiting fatty acid transport in the liver but promoting the exocrine function of the pancreas.

  2. Deposition of stearate-oleate rich seed fat in Mangifera indica is mediated by a FatA type acyl-ACP thioesterase.

    PubMed

    Bhattacharjee, Ashish; Ghosh, Santosh K; Neogi, Krishnakali; Aich, Aniruddha; Willard, Belinda; Kinter, Michael; Sen, Soumitra K; Ghosh, Dolly; Ghosh, Sudhamoy

    2011-02-01

    Although the mechanism of accumulation of C8-C16 saturated fatty acids in seed oils has been well-studied, the control of stearic (C18:0) acid deposition in high stearate seed fat is still unclear. We investigated the mechanism that regulates high level of stearate and oleate (C18:1) accumulation in mango (Mangifera indica) seeds during its development, and examined the seed plastid extracts for induction of any specialized fatty acyl-ACP thioesterase (Fat) that may control this high level of deposition. Though the specificity of the Fat enzymes does not account directly for the fatty acid composition of mango seeds, our result suggested that an induced synthesis of a FatA type of thioesterase could be responsible for the high content of oleate and stearate in its seed fat. The major thioesterase from developing seed kernel was purified to near homogeneity, and characterized as a heat-labile, dimeric, neutral protein with relative substrate specificity of 100:35:1.8 towards oleoyl-, stearoyl- and palmitoyl-ACP, respectively. This enzyme was confirmed as Mi FatA by mass spectrometric analysis. Additionally, a heat-stable FatB type enzyme (Mi FatB) was also partially purified, with relative substrate specificity for the same substrates as 9:8.5:100, respectively. Mi FatA is an enzyme of great biotechnological interest because of its involvement in the regulation of stearate rich seed fat in mango.

  3. A proprietary topical preparation containing EGCG-stearate and glycerin with inhibitory effects on herpes simplex virus: case study.

    PubMed

    Zhao, Man; Jiang, Jinyan; Zheng, Rongrong; Pearl, Henna; Dickinson, Douglas; Fu, Baiping; Hsu, Stephen

    2012-10-01

    The effects of a proprietary topical formulation containing EGCG-stearate in 100% glycerin USP were studied in two volunteer patients with recurrent herpes simplex (HSV) type 1. Application during early onset (prodromal stage) in a patient with herpes labialis prevented lesion progression. In a second patient with herpetic stomatitis, application of the formula during a later stage (inflammation stage) led to a remarkably shortened duration of symptoms. In contrast, a third patient provided 100% glycerin USP only as placebo failed to demonstrate any therapeutic or preventive effect against lesion occurrence or duration of lesion and healing time. These results suggest that this proprietary topical preparation could be used effectively to prevent and treat HSV-induced symptoms, and warrants further clinical investigation.

  4. Influence of two different alcohols in the esterification of fatty acids over layered zinc stearate/palmitate.

    PubMed

    de Paiva, Eduardo José Mendes; Corazza, Marcos Lúcio; Sierakowski, Maria Rita; Wärnå, Johan; Murzin, Dmitry Yu; Wypych, Fernando; Salmi, Tapio

    2015-10-01

    In this work, esterification of fatty acids (oleic, linoleic and stearic acid) with a commercial zinc carboxylate (a layered compound formed by simultaneous intercalation of stearate and palmitate anions) was performed. Kinetic modeling using a quasi-homogeneous approach successfully fitted experimental data at different molar ratio of fatty acids/alcohols (1-butanol and 1-hexanol) and temperature. An apparent first-order reaction related to all reactants was found and activation energy of 66 kJ/mol was reported. The catalyst showed to be unique, as it can be easily recovered like a heterogeneous catalysts behaving like ionic liquids. In addition, this catalyst demonstrated a peculiar behavior, because higher reactivity was observed with the increase in the alcohols chain length compared to the authors' previous work using ethanol.

  5. Liver-targeting self-assembled hyaluronic acid-glycyrrhetinic acid micelles enhance hepato-protective effect of silybin after oral administration.

    PubMed

    Han, Xiaofeng; Wang, Zhe; Wang, Manyuan; Li, Jing; Xu, Yongsong; He, Rui; Guan, Hongyu; Yue, Zhujun; Gong, Muxin

    2016-06-01

    In order to enhance oral bioavailability and liver targeting delivery of silybin, two amphiphilic hyaluronic acid derivatives, hyaluronic acid-deoxycholic acid (HA-adh-DOCA) and hyaluronic acid-glycyrrhetinic acid (HA-adh-GA) conjugates, were designed and synthesized. Silybin was successfully loaded in HA-adh-DOCA and HA-adh-GA micelles with high drug-loading capacities (20.3% ± 0.5% and 20.6% ± 0.6%, respectively). The silybin-loaded micelles were spherical in shape with the average size around 130 nm. In vitro release study showed that two silybin-loaded micelles displayed similar steady continued-release pattern in simulated gastrointestinal fluids and PBS. Single-pass intestinal perfusion studies indicated that silybin-loaded micelles were absorbed in the whole intestine and transported via a passive diffusion mechanism. Compared with suspension formulation, silybin-loaded HA-adh-DOCA and HA-adh-GA micelles achieved significantly higher AUC and Cmax level. Moreover, liver targeting drug delivery of micelles was confirmed by in vivo imaging analysis. In comparison between the two micellar formulations, HA-adh-GA micelles possessed higher targeting capacity than HA-adh-DOCA micelles, owing to the active hepatic targeting properties of glycyrrhetinic acid. In the treatment of acute liver injury induced by CCl4, silybin-loaded HA-adh-GA micelles displayed better effects over suspension control and silybin-loaded HA-adh-DOCA micelles. Overall, pharmaceutical and pharmacological indicators suggested that the HA-adh-GA conjugates can be successfully utilized for liver targeting of orally administered therapeutics.

  6. Synergistic effect of combination of Irganox 1010 and zinc stearate on thermal stabilization of electron beam irradiated HDPE/EVA both in hot water and oven

    NASA Astrophysics Data System (ADS)

    Hassanpour, S.; Khoylou, F.

    2007-11-01

    Thermo-oxidative stability of HDPE/EVA blends can be considerably increased by combination of a high-molecular weight phenolic antioxidant and zinc stearate. In this work, the post-irradiation thermal stability of HDPE/EVA blends has been studied. High-density polyethylene and its blends with ethylene-vinylacetate copolymer in both pure form and mixed with Irganox 1010 and zinc stearate were exposed to electron beam radiation at doses between 80 and 150 kGy, at room temperature, in air. In order to evaluate the thermal stability of the samples, post-irradiation heat treatments were done in both hot water bath at 95 °C and in an oven at 140 °C. The mechanical properties and changes in the chemical structure were determined during thermal aging in hot water and oven. The gel content was enhanced by increasing EVA concentration in all applied doses. The stabilized blends have lower gel content than the unstabilized samples. From the results of heat aging treatments it was observed that the thermal stability of the unstabilized blend samples was lower than HDPE. Thermal stability of the samples has been improved by incorporation of Irganox 1010 and zinc stearate. Formation of hydroxyl group was insignificant for stabilized samples during heat aging in both conditions. Also, the changes in the value of oxidation induction time (OIT) for the stabilized samples were negligible after prolonged immersion in hot water.

  7. Alginate gel-coated oil-entrapped alginate-tamarind gum-magnesium stearate buoyant beads of risperidone.

    PubMed

    Bera, Hriday; Boddupalli, Shashank; Nandikonda, Sridhar; Kumar, Sanoj; Nayak, Amit Kumar

    2015-01-01

    A novel alginate gel-coated oil-entrapped calcium-alginate-tamarind gum (TG)-magnesium stearate (MS) composite floating beads was developed for intragastric risperidone delivery with a view to improving its oral bioavailability. The TG-blended alginate core beads containing olive oil and MS as low-density materials were accomplished by ionotropic gelation technique. Effects of polymer-blend ratio (sodium alginate:TG) and crosslinker (CaCl2) concentration on drug entrapment efficiency (DEE, %) and cumulative drug release after 8 h (Q8h, %) were studied to optimize the core beads by a 3(2) factorial design. The optimized beads (F-O) exhibited DEE of 75.19±0.75% and Q8h of 78.04±0.38% with minimum errors in prediction. The alginate gel-coated optimized beads displayed superior buoyancy and sustained drug release property. The drug release profiles of the drug-loaded uncoated and coated beads were best fitted in Higuchi kinetic model with Fickian and anomalous diffusion driven mechanisms, respectively. The optimized beads yielded a notable sustained drug release profile as compared to marketed immediate release preparation. The uncoated and coated Ca-alginate-TG-MS beads were also characterized by SEM, FTIR and P-XRD analyses. Thus, the newly developed alginate-gel coated oil-entrapped alginate-TG-MS composite beads are suitable for intragastric delivery of risperidone over a prolonged period of time.

  8. Amended final report on the safety assessment of glyceryl dilaurate, glyceryl diarachidate, glyceryl dibehenate, glyceryl dierucate, glyceryl dihydroxystearate, glyceryl diisopalmitate, glyceryl diisostearate, glyceryl dilinoleate, glyceryl dimyristate, glyceryl dioleate, glyceryl diricinoleate, glyceryl dipalmitate, glyceryl dipalmitoleate, glyceryl distearate, glyceryl palmitate lactate, glyceryl stearate citrate, glyceryl stearate lactate, and glyceryl stearate succinate.

    PubMed

    2007-01-01

    Glyceryl Dilaurate, Glyceryl Diarachidate, Glyceryl Dibehenate, Glyceryl Dierucate, Glyceryl Dihydroxystearate, Glyceryl Diisopalmitate, Glyceryl Diisostearate, Glyceryl Dilinoleate, Glyceryl Dimyristate, Glyceryl Dioleate, Glyceryl Diricinoleate, Glyceryl Dipalmitate, Glyceryl Dipalmitoleate, Glyceryl Distearate, Glyceryl Palmitate Lactate, Glyceryl Stearate Citrate, Glyceryl Stearate Lactate, and Glyceryl Stearate Succinate are diacylglycerols (also known as diglycerides or glyceryl diesters) that function as skin conditioning agents - emollients in cosmetics. Only Glyceryl Dilaurate (up to 5%), Glyceryl Diisostearate (up to 43%), Glyceryl Dioleate (up to 2%), Glyceryl Distearate (up to 7%), and Glyceryl Stearate Lactate (up to 5%) are reported to be in current use. Production proceeds from fully refined vegetable oils, which are further processed using hydrogenation and fractionation techniques, and the end products are produced by reacting selected mixtures of the partly hydrogenated, partly fractionated oils and fats with vegetable-derived glycerine to yield partial glycerides. In the final stage of the production process, the products are purified by deodorization, which effectively removes pesticide residues and lower boiling residues such as residues of halogenated solvents and aromatic solvents. Diglycerides have been approved by the Food and Drug Administration (FDA) for use as indirect food additives. Nominally, these ingredients are 1,3-diglycerides, but are easily isomerized to the 1,2-diglycerides form. The 1,3-diglyceride isomer is not a significant toxicant in acute, short-term, subchronic, or chronic animal tests. Glyceryl Dilaurate was a mild primary irritant in albino rabbits, but not a skin sensitizer in guinea pig maximization tests. Diacylglycerol Oil was not genotoxic in the Ames test, in mammalian Chinese hamster lung cells, or in a rodent bone marrow micronucleus assay. An eye shadow containing 1.5% Glyceryl Dilaurate did not induce skin

  9. Characterization of the interaction of glycyrrhizin and glycyrrhetinic acid with bovine serum albumin by spectrophotometric-gradient flow injection titration technique and molecular modeling simulations.

    PubMed

    Manouchehri, Firouzeh; Izadmanesh, Yahya; Ghasemi, Jahan B

    2017-09-01

    In this research, the interactions of glycyrrhizin (GL) and glycyrrhetinic acid (GA) with bovine serum albumin (BSA) have been investigated by the novel method of spectrophotometric- gradient flow injection titration technique. The hard-modeling multivariate approach to binding was used for calculation of binding constants and estimation of concentration-spectral profiles of equilibrium species. The stoichiometric ratio of binding was estimated using eigenvalue analysis. Results showed that GL and GA bind BSA with overall binding constants of KGL-BSA=3.85 (±0.09)×10(4)Lmol(-1), KGA-BSA=3.08 (±0.08)×10(4)Lmol(-1). Ligand-BSA complexes were further analyzed by combined docking and molecular dynamics (MD) simulations. Docking simulations were performed to obtain a first guess on the binding structure of the GL/GA-BSA complex, and subsequently analyzed by 20 ns MD simulations in order to evaluate interactions of GL/GA with BSA in detail. Results of MD simulations indicated that GL-BSA complex forms mainly on the basis of hydrogen bonds, while, GA-BSA complex forms on the basis of hydrophobic interactions. Also, water molecules can bridge between the ligand and protein by hydrogen bonds, which are stable during the entire simulation and play an important role in stabilization of the GL/GA-BSA complexes. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 18β-glycyrrhetinic acid suppresses gastric cancer by activation of miR-149-3p-Wnt-1 signaling

    PubMed Central

    Cao, Donghui; Jia, Zhifang; You, Lili; Wu, Yanhua; Hou, Zhen; Suo, Yueer; Zhang, Houjun; Wen, Simin; Tsukamoto, Tetsuya; Oshima, Masanobu; Jiang, Jing; Cao, Xueyuan

    2016-01-01

    18β-glycyrrhetinic acid (GRA) exerts anti-tumor effects on various types of cancer. In the present study, we found that GRA attenuated the severity of gastritis and suppressed gastric tumorigenesis in transgenic mice. We also discovered that miR-149-3p was downregulated in gastric cancer tissues and cell lines as compared to normal gastric tissues and epithelial cells, but was upregulated by GRA. miR-149-3p expression also correlated negatively with lymphnode metastasis. Our functional assays showed that miR-149-3p overexpression inhibited cell proliferation and cell cycle progression while inducing apoptosis, while inhibition of miR-149-3p had the opposite effects. In addition, we identified Wnt-1 as a direct target of miR-149-3p. These data suggest that GRA inhibits the initiation and progression of gastric tumors by ameliorating the inflammatory microenvironment through downregulation of COX-2 expression and by inhibiting Wnt-1 expression through the upregulation of tumor suppressor miR-149-3p. GRA may thus have the potential to serve as a useful therapeutic agent for the prevention and treatment of gastric cancer. PMID:27713126

  11. 18α-Glycyrrhetinic Acid Induces Apoptosis of HL-60 Human Leukemia Cells through Caspases- and Mitochondria-Dependent Signaling Pathways.

    PubMed

    Huang, Yi-Chang; Kuo, Chao-Lin; Lu, Kung-Wen; Lin, Jen-Jyh; Yang, Jiun-Long; Wu, Rick Sai-Chuen; Wu, Ping-Ping; Chung, Jing-Gung

    2016-07-01

    In this study we investigate the molecular mechanisms of caspases and mitochondria in the extrinsic and intrinsic signal apoptosis pathways in human leukemia HL-60 cells after in vitro exposure to 18α-glycyrrhetinic acid (18α-GA). Cells were exposed to 18α-GA at various concentrations for various time periods and were harvested for flow cytometry total viable cell and apoptotic cell death measurements. Cells treated with 18α-GA significantly inhibited cell proliferation and induced cell apoptosis in a dose-dependent manner, with an IC50 value of 100 μM at 48 h. The cell growth inhibition resulted in induction of apoptosis and decreased the mitochondria membrane potential (ΔΨm) and increased caspase-8, -9 and -3 activities. Furthermore, cytochrome c and AIF were released from mitochondria, as shown by western blotting and confirmed by confocal laser microscopy. Western blotting showed that 18α-GA increased the levels of pro-apoptotic proteins such as Bax and Bid and decreased the anti-apoptotic proteins such as Bcl-2 and Bcl-xl, furthermore, results also showed that 18α-GA increased Fas and Fas-L which are associated with surface death receptor in HL-60 cells. Based on those observations, the present study supports the hypothesis that 18α-GA-induced apoptosis in HL-60 cells involves the activation of the both extrinsic and intrinsic apoptotic pathways.

  12. Stearate organogel-gelatin hydrogel based bigels: physicochemical, thermal, mechanical characterizations and in vitro drug delivery applications.

    PubMed

    Sagiri, Sai Sateesh; Singh, Vinay K; Kulanthaivel, Senthilguru; Banerjee, Indranil; Basak, Piyali; Battachrya, M K; Pal, Kunal

    2015-03-01

    Over the past decade, researchers have been trying to develop alternative gel based formulations in comparison to the traditional hydrogels and emulgels. In this perspective, bigels were synthesized by mixing gelatin hydrogel and stearic acid based organogel by hot emulsification method. Two types of bigels were synthesized using sesame oil and soy bean oil based stearate organogels. Gelatin based emulgels prepared using sesame oil and soy bean oil were used as the controls. Microscopic studies revealed that the bigels contained aggregates of droplets, whereas, emulgels showed dispersed droplets within the continuum phase. The emulgels showed higher amount of leaching of oils, whereas, the leaching of the internal phase was negligible from the bigels. Presence of organogel matrix within the bigels was confirmed by XRD, FTIR and DSC methods. Bigels showed higher mucoadhesive and mechanical properties compared to emulgels. Cyclic creep-recovery and stress relaxation studies confirmed the viscoelastic nature of the formulations. Four elemental Burger's model was employed to analyze the cyclic creep-recovery data. Cyclic creep-recovery studies suggested that the deformation of the bigels were lower due to the presence of the organogels within its structure. The formulations showed almost 100% recovery after the creep stage and can be explained by the higher elastic nature of the formulations. Stress relaxation study showed that the relaxation time was higher in the emulgels as compared to the bigels. Also, the % relaxation was higher in emulgels suggesting its fluid dominant nature. The in vitro biocompatibility of the bigels was checked using human epidermal keratinocyte cell line (HaCaT). Both emulgels and bigels were biocompatible in nature. The in vitro drug (ciprofloxacin) release behavior indicated non-Fickian diffusion of the drug from the matrices. The drug release showed good antimicrobial effect against Escherichia coli. Based on the results, it was concluded

  13. Sucrose stearate-enriched lipid matrix tablets of etodolac: modulation of drug release, diffusional modeling and structure elucidation studies.

    PubMed

    Abd-Elbary, Ahmed; Tadros, Mina Ibrahim; Alaa-Eldin, Ahmed Adel

    2013-06-01

    Etodolac is a non-steroidal anti-inflammatory drug having an elimination half-life of 7 h; oral doses are given every 6-8 h. The aim of current work was the development of controlled-release etodolac lipid matrix tablets. The variables influencing design of these tablets (L1-L28) by the hot fusion method were investigated including; (1) lipid type (stearic acid, cetyl alcohol, cetostearyl alcohol, Imwitor® 900K, Precirol® ATO 5 and Compritol® ATO 888), (2) drug/lipid ratio (1:0.25 and 1:0.50, respectively), (3) filler type (lactose, Avicel® PH101 and their physical mixtures; 2:1, 1:1, and 1:2, respectively), (4) surfactant's HLB (5 and 11), and (5) drug/surfactant ratio (20:1 and 10:1, respectively). Statistical analysis and kinetic modeling of drug release data were evaluated. The inner matrix of the tablet was visualized via scanning electron microscopy (SEM). An inverse correlation was observed between the drug/lipid ratio and the drug release rate. Precirol®- and Compritol®-containing formulae showed more retarded drug release rates. Lactose/Avicel® physical mixture (1:1) was considered as a filler of choice where it minimized the burst effect observed with Avicel®-free formulae. The higher surfactant's HLB, the higher drug release rate. The similarity factor (f(2)) between the drug release profiles revealed similarity within the investigated drug/surfactant ratios. Sucrose stearate D1805®-based matrix (L21) succeeded in delivering more than 90% of etodolac over 12 h, following anomalous (non-Fickian) controlled-release kinetics. SEM micrographs confirmed pore formation, within the latter matrix, upon contact with dissolution medium.

  14. Investigation of the potential for direct compaction of a fine ibuprofen powder dry-coated with magnesium stearate.

    PubMed

    Qu, Li; Zhou, Qi Tony; Gengenbach, Thomas; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Gamlen, Michael; Morton, David A V

    2015-05-01

    Intensive dry powder coating (mechanofusion) with tablet lubricants has previously been shown to give substantial powder flow improvement. This study explores whether the mechanofusion of magnesium stearate (MgSt), on a fine drug powder can substantially improve flow, without preventing the powder from being directly compacted into tablets. A fine ibuprofen powder, which is both cohesive and possesses a low-melting point, was dry coated via mechanofusion with between 0.1% and 5% (w/w) MgSt. Traditional low-shear blending was also employed as a comparison. No significant difference in particle size or shape was measured following mechanofusion. For the low-shear blended powders, only marginal improvement in flowability was obtained. However, after mechanofusion, substantial improvements in the flow properties were demonstrated. Both XPS and ToF-SIMS demonstrated high degrees of a nano-scale coating coverage of MgSt on the particle surfaces from optimized mechanofusion. The study showed that robust tablets were produced from the selected mechanofused powders, at high-dose concentration and tablet tensile strength was further optimized via addition of a Polyvinylpyrrolidone (PVP) binder (10% w/w). The tablets with the mechanofused powder (with or without PVP) also exhibited significantly lower ejection stress than those made of the raw powder, demonstrating good lubrication. Surprisingly, the release rate of drug from the tablets made with the mechanofused powder was not retarded. This is the first study to demonstrate such a single-step dry coating of model drug with MgSt, with promising flow improvement, flow-aid and lubrication effects, tabletability and also non-inhibited dissolution rate.

  15. Novel ultrasound contrast agent based on microbubbles generated from surfactant mixtures of Span 60 and polyoxyethylene 40 stearate.

    PubMed

    Xing, Zhanwen; Ke, Hengte; Wang, Jinrui; Zhao, Bo; Yue, Xiuli; Dai, Zhifei; Liu, Jibin

    2010-09-01

    In this study, novel perfluorocarbon-filled microbubbles as ultrasound contrast agent were fabricated using ultrasonication of a surfactant mixture of sorbitan monostearate (Span 60) and polyoxyethylene 40 stearate (PEG40S) in aqueous media. The microbubbles generated from a 1:9 mixture of PEG40S/Span 60 exhibited an average diameter of 2.08+/-1.27 microm. More than 99% of the microbubbles had a mean particle diameter less than 8 microm, indicating that they were appropriately sized for intravenous administration as ultrasound contrast agent. The stabilization mechanism of the microbubbles was investigated by the Langmuir-Blodgett technique including the measurements of surface pressure-area (pi-A) isotherms and compression-decompression cycles with a two-dimensional monolayer of Span 60 and PEG40S. The dependence on molar fraction of PEG40S in pi-A isotherms of mixed monolayers provided a strong evidence of interactions between the two microbubble-forming materials. It is suggested that the monolayer shell imparts good stability to the microbubbles by three means: (1) a low surface tension monolayer hinders dissolution through the reduction of surface tension, which introduces a mechanical surface pressure that counters the Laplace pressure; (2) the presence of a monolayer shell imparts a significant barrier to gas escaping from the core into the aqueous medium; and (3) encapsulation elasticity stabilizes microbubbles against diffusion-driven dissolution and explains the long shelf-life of microbubble contrast agent. The preliminary in vivo ultrasound imaging study showed that such stabilized microbubbles demonstrated excellent enhancement under grey-scale pulse inversion harmonic imaging and power Doppler imaging. 2010 Acta Materialia Inc. All rights reserved.

  16. Gas adsorption on commercial magnesium stearate: Effects of degassing conditions on nitrogen BET surface area and isotherm characteristics.

    PubMed

    Lapham, Darren P; Lapham, Julie L

    2017-09-15

    Commercial grades of magnesium stearate have been analysed by nitrogen adsorption having been pre-treated at temperatures between 30°C and 110°C and in the as-received state. Characteristics of nitrogen adsorption/desorption isotherms are assessed through the linearity of low relative pressure isotherm data and the BET transform plot together with the extent of isotherm hysteresis. Comparison is made between thermal gravimetric analysis and mass loss on drying. Features of gas adsorption isotherms considered atypical are identified and possible causes presented. It is shown that atypical isotherm features and issues of applying BET theory to the calculation of SBET are linked to the presence of hydrated water and that these depend on the hydration state: being more pronounced for the di-hydrate than the mono-hydrate. Dehydration reduces the extent of atypical features. SBET of a mono-hydrate sample is 5.6m(2)g(-1) and 3.2m(2)g(-1) at 40°C and 100°C degassing respectively but 23.9m(2)g(1) and 5.9m(2)g(-1) for di-hydrate containing samples under comparable degassing. Di-hydrated samples also show SBET >15m(2)g(1), BET C-values <7 and BET correlation coefficients <0.98 before dehydration. Possible mechanisms for atypical isotherms are critically discussed together with the suitability of applying BET theory to nitrogen adsorption data. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Effect of moisture content on solid-state interaction at the interface between magnesium stearate and captopril

    NASA Astrophysics Data System (ADS)

    Cheng, Wen-Ting; Wang, Shun-Li; Lin, Shan-Yang

    2008-12-01

    A grinding process was used to accelerate the solid-state interaction at the interface between magnesium stearate (MgSt) and captopril (CAP) in the presence or absence of water. The 110 °C-preheated MgSt/CAP or MgSt/CAP ground mixture showed a 5.06% (w/w) or 6.07% (w/w) water content, respectively, which was >4.29% (w/w) for the original MgSt alone. The increased water content in each ground mixture was due to the atmospheric absorption of water caused by grinding. A small infrared (IR) peak at 1562 cm -1 appeared in the IR spectrum of the 110 °C-preheated MgSt/CAP ground mixture, whereas a stronger IR peak at 1541 cm -1 with a shoulder at 1556 cm -1 was observed for the MgSt/CAP ground mixture. These IR peaks were possibly related to the solid-state interaction at the interface between MgSt and CAP via hydrogen bonding of adsorbed water. However, an excess of water added in the MgSt/CAP ground mixture could exacerbate the solid-state interaction of MgSt and CAP to form a stearic acid as evidenced by the IR peak at 1705 cm -1. This may be due to the neutralization between basic MgSt and acidic CAP. In addition, thermal Fourier transform infrared (FTIR) microspectroscopy also confirmed that the thermal-dependent dehydration process might alter the IR peak intensity of MgSt/CAP ground mixtures.

  18. Influence of trehalose on the interaction of curcumin with surface active ionic liquid micelle and its vesicular aggregate composed of a non-ionic surfactant sorbitan stearate

    NASA Astrophysics Data System (ADS)

    Roy, Arpita; Dutta, Rupam; Sarkar, Nilmoni

    2016-11-01

    The present investigation unravels the effect of trehalose on 1-hexadecyl-3-methylimidazolium chloride ([C16mim]Cl), a cationic surface active ionic liquid (SAIL) micelle and SAIL ([C16mim]Cl)-nonionic surfactant (Sorbitan Stearate, Span 60) based vesicles. The influence of trehalose on size and morphology of the aggregates has been investigated using dynamic light scattering (DLS) and transmission electron microscopic (TEM) measurements. Besides, we have studied the dynamic properties of curcumin inside these aggregates using fluorescence spectroscopic based techniques. The results revealed that trehalose molecules play crucial role in modulation of the photophysical properties of curcumin in these organized assemblies.

  19. In Silico and In Vivo Anti-Malarial Studies of 18β Glycyrrhetinic Acid from Glycyrrhiza glabra

    PubMed Central

    Kalani, Komal; Agarwal, Jyoti; Alam, Sarfaraz; Khan, Feroz; Pal, Anirban; Srivastava, Santosh Kumar

    2013-01-01

    Malaria is one of the most prevailing fatal diseases causing between 1.2 and 2.7 million deaths all over the world each year. Further, development of resistance against the frontline anti-malarial drugs has created an alarming situation, which requires intensive drug discovery to develop new, more effective, affordable and accessible anti-malarial agents possessing novel modes of action. Over the past few years triterpenoids from higher plants have shown a wide range of anti-malarial activities. As a part of our drug discovery program for anti-malarial agents from Indian medicinal plants, roots of Glycyrrhizaglabra were chemically investigated, which resulted in the isolation and characterization of 18β-glycyrrhetinic acid (GA) as a major constituent. The in vitro studies against P. falciparum showed significant (IC50 1.69µg/ml) anti-malarial potential for GA. Similarly, the molecular docking studies showed adequate docking (LibDock) score of 71.18 for GA and 131.15 for standard anti-malarial drug chloroquine. Further, in silico pharmacokinetic and drug-likeness studies showed that GA possesses drug-like properties. Finally, in vivo evaluation showed a dose dependent anti-malarial activity ranging from 68–100% at doses of 62.5–250mg/kg on day 8. To the best of our knowledge this is the first ever report on the anti-malarial potential of GA. Further work on optimization of the anti-malarial lead is under progress. PMID:24086367

  20. Glycyrrhetinic acid and E.resveratroloside act as potential plant derived compounds against dopamine receptor D3 for Parkinson’s disease: a pharmacoinformatics study

    PubMed Central

    Mirza, Muhammad Usman; Mirza, A Hammad; Ghori, Noor-Ul-Huda; Ferdous, Saba

    2015-01-01

    Parkinson’s disease (PD) is caused by loss in nigrostriatal dopaminergic neurons and is ranked as the second most common neurodegenerative disorder. Dopamine receptor D3 is considered as a potential target in drug development against PD because of its lesser side effects and higher degree of neuro-protection. One of the prominent therapies currently available for PD is the use of dopamine agonists which mimic the natural action of dopamine in the brain and stimulate dopamine receptors directly. Unfortunately, use of these pharmacological therapies such as bromocriptine, apomorphine, and ropinirole provides only temporary relief of the disease symptoms and is frequently linked with insomnia, anxiety, depression, and agitation. Thus, there is a need for an alternative treatment that not only hinders neurodegeneration, but also has few or no side effects. Since the past decade, much attention has been given to exploitation of phytochemicals and their use in alternative medicine research. This is because plants are a cheap, indispensable, and never ending resource of active compounds that are beneficial against various diseases. In the current study, 40 active phytochemicals against PD were selected through literature survey. These ligands were docked with dopamine receptor D3 using AutoDock and AutoDockVina. Binding energies were compared to docking results of drugs approved by the US Food and Drug Administration against PD. The compounds were further analyzed for their absorption, distribution, metabolism, and excretion-toxicity profile. From the study it is concluded that glycyrrhetinic acid and E.resveratroloside are potent compounds having high binding energies which should be considered as potential lead compounds for drug development against PD. PMID:25565772

  1. The effects of 18β-glycyrrhetinic acid and glycyrrhizin on intestinal absorption of paeoniflorin using the everted rat gut sac model.

    PubMed

    He, Rui; Xu, Yongsong; Peng, Jingjing; Ma, Tingting; Li, Jing; Gong, Muxin

    2017-01-01

    Paeoniflorin (PF), the main active component of Shaoyao-Gancao-tang, possesses significantly antinociceptive effects and many other pharmacological activities. However, its poor intestinal absorption results in low bioavailability. Therefore, enhancing PF absorption plays a vital role in exerting its therapeutic effect. Shaoyao combined with Gancao exhibited a synergistic effect. The enhancement of PF absorption through the interaction of its constituents in intestinal absorption would be greatly implicated. The present study aimed at investigating the effects of glycyrrhizin, the main constituent of Gancao, and its main metabolite, 18β-glycyrrhetinic acid (18β-GA), on the intestinal absorptive behavior of PF, and the role of P-glycoprotein (P-gp) in PF absorption using the in vitro everted rat gut sac model. The results demonstrated that 1 mM of 18β-GA significantly increased PF absorption in both the jejunum and the ileum, while 100 μM of 18β-GA only promoted the ileum absorption and had no obvious effect on the jejunum absorption. The effect of glycyrrhizin on intestinal PF absorption was related to concentrations. One mM of glycyrrhizin significantly increased PF absorption in the jejunum after 45 min and in the ileum after 90 min. But 100 μM of glycyrrhizin had an inhibitory effect in the jejunum and no effect in the ileum before 60 min. Moreover, verapamil, the well-known P-gp inhibitor, could significantly enhance the PF absorption. In conclusion, the influence of 18β-GA and glycyrrhizin on the PF absorption was related to concentrations and intestinal segments. This might be involved in the intervention of efflux transport of PF mediated by intestinal P-gp.

  2. The liquorice root derivative glycyrrhetinic acid can ameliorate ionoregulatory disturbance in rainbow trout (Oncorhynchus mykiss) abruptly exposed to ion-poor water.

    PubMed

    Chen, Chun Chih; Kolosov, Dennis; Kelly, Scott P

    2016-09-01

    To consider the idea that a dietary botanical supplement could act as an adaptogen in a teleost fish, the effect of a liquorice root derivative (18β-glycyrrhetinic acid, 18βGA) on rainbow trout following an acute ionoregulatory stressor was examined. Freshwater (FW) trout were fed a control or 18βGA supplemented diet (0, 5, or 50μg 18βGA/g diet) for 2weeks, then abruptly exposed to ion-poor water (IPW) for 24h. Following IPW exposure, muscle moisture content and serum cortisol levels elevated and serum [Na(+)] and/or [Cl(-)] reduced in control and 50μg/g 18βGA-fed fish. However, these endpoints were unaltered in 5μg/g 18βGA-fed fish. Gill tissue was investigated for potential mechanisms of 18βGA action by examining mRNA abundance of genes encoding corticosteroid receptors (CRs), 11β-hydroxysteroid dehydrogenase 2 (11β-hsd2), and tight junction (TJ) proteins, as well as Na(+)-K(+)-ATPase and H(+)-ATPase activity, and mitochondrion-rich cell (MRC) morphometrics. Following IPW exposure, CR and 11β-hsd2 mRNA, MRC fractional surface, Na(+)-K(+)-ATPase and H(+)-ATPase activity were unaltered or decreased in 50μg 18βGA fish, as was mRNA encoding select TJ proteins. In contrast, 5μg 18βGA-fed fish exhibited elevated 11β-hsd2 and CR mRNA abundance versus 50μg 18βGA-fed, and reduced MRC apical area as well as some differences in TJ protein mRNA abundance versus control fish. Data suggest that 18βGA, at low levels, may be adaptogenic in trout and might help to ameliorate ionoregulatory perturbation following IPW exposure. This seems to occur, in part, through 18βGA-induced alterations in the biochemistry and physiology of the gill. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. [Effects of 18β-glycyrrhetinic Acid on the Expression of CCL11, AQP1 and EOS in Nasal Mucosa of Allergic Rhinitis Rats].

    PubMed

    Li, Juan-li; Xi, Ke-hu; Hou, Yun; Jiang, Ying; Gui, Yan; Wang, You-hu; Zhang, Fu-hong; Zhang, Xiao-bing

    2015-05-01

    To investigate the effects of 18β-glycyrrhetinic acid (GA) on the expression of eotaxin 1 (CCL11), aquaporin protein 1 (AQP1) and eosinophil (EOS) in nasal mucosa of allergic rhinitis (AR) rats. Seventy six Wistar rats were randomly divided into 4 groups, normal control (NC) group, AR model (AR) group, loratadine (LOA) group and 18β-GA group. All the mice in AR, LOA and 18β-GA groups were sensitized intraperitoneally with OVA and AL(OH), from day 1-14, then induced by intranasal administration with OVA from day 14-21, while the mice in NC group were sensitized with saline. The mice in both LOA and 18β-GA group were given LOA and 18β-GA once a day respectively from the 21 d, while the mice in AR and NC groups were administrated with saline. At the end of 1 week, 2 weeks and 3 weeks, the behavioral changes of mice were observed and recorded, the level of CCL11 mRNA was measured by RT-QPCR, and AQP1 expression was investiaged by SP staing. EOS in nasal mucosa was studied with the methods of HE staining. Compared with NC group, AR group showed typical AR symptoms. With the treatments, AR symptom scores and the expression levels of CCL11, AQP1 and EOS in nasal mucosa were improved significantly (P<0. 05). When compared with AR group, the above statistics in LOA group were down-regulated evidently at different points in time (P<. 05). At the end of 1 week, the above detection results in 18β-GA group were lower than those in AR group (P<0. 05). At the end of 2 weeks, those parameters approached to the levels of LOA and NC group significantly. 18β-GA administration could down-regulate the expression levels of CCL11, AQP1 and EOS in nasal mucosa of allergic rhinitis rats and cast effects on inhibiting the progress of AR.

  4. Comparison of near-infrared and laser-induced breakdown spectroscopy for determination of magnesium stearate in pharmaceutical powders and solid dosage forms.

    PubMed

    Green, Robert L; Mowery, Mark D; Good, Julie A; Higgins, John P; Arrivo, Steven M; McColough, Kristen; Mateos, Arthur; Reed, Robert A

    2005-03-01

    Near-infrared (NIR) spectroscopy has become well established in both the pharmaceutical arena and other areas as a useful technique for rapid quantitative analysis of solid materials. Though laser-induced breakdown spectroscopy (LIBS) has not been widely applied in the pharmaceutical industry, the technique has been used for rapid quantitative analysis of solids in many other applications. One analysis amenable to each technique is the determination of magnesium stearate in solids during the lubrication blending unit operation of pharmaceutical processing. A comparative study of the utility of these two techniques for this application will be presented. Necessary sample preparations and the extent and type of matrix effects will be discussed. Additionally, it will be shown that NIR provides better accuracy and precision than LIBS with the experimental parameters used; however, LIBS showed superior selectivity as it was demonstrated to be more robust to sample matrix perturbations. Examples of blending applications will also be presented.

  5. Scale effects in tribological properties of solid-lubricating composites made of ultra-high molecular weight polyethylene filled with calcium stearate particles

    NASA Astrophysics Data System (ADS)

    Lurie, S. A.; Volkov-Bogorodskiy, D. B.; Knyzeva, A. G.; Panin, S. V.; Kornienko, L. A.

    2016-04-01

    Friction properties being influenced by scale effects are simulated in the paper by the example of polymer composite material made from Ultra High-Molecular Weight Polyethylenes (UHMWPE) filled by calcium stearate (C36H70CaO4). Of interest are the composites whose mechanical properties and tribotechnical characteristics do not depend monotonically on filler (inclusions) weight fraction. In order to describe the influence of scale effects onto frictional properties the model based on Reiss averaging (model of "weak phase") is employed. It is also suggested that when gradient elasticity theory is applicable the formal analogy between effective friction coefficient for surface heterogeneous structures and effective mechanical properties (compliances) for heterogeneous material can take place. Theoretical dependence to describe nonmonotonic change of effective friction coefficient versus filler concentration was obtained for the polymer composites under study. The suggested expressions might be useful for the sake of properties prognosis of antifriction polymeric materilas.

  6. Application of the quantitative detection of a change in concentration of magnesium stearate in a feeder tube of tableting manufacture by real-time near-infrared spectroscopy.

    PubMed

    Sasakura, D; Nakayama, K; Chikuma, T

    2015-10-01

    Process analytical technology is important for the analysis and control of manufacturing processes. Near-infrared spectroscopy is widely used in various process analytical technologies for the analysis of the chemical componentsof solid dosage forms. Lubrication is an important process carried out before a tablet is produced. In this process, the concentration of lubricant, such as magnesium stearate (StMg), might change for one of many reasons during powder transport, which would be a critical problem such as variation in tablet compressibility and dissolution failure of compressed tablets. Our group investigated the feasibility of the quantitative monitoring of a change in the concentration of StMg in the feeder tube of tableting equipment employing real-time near-infrared spectroscopy.

  7. Simultaneous quantification of catechin, epicatechin, liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin, piperine and glycyrrhetinic acid in rat plasma by HPLC-MS/MS: application to a pharmacokinetic study of Longhu Rendan pills.

    PubMed

    Wang, Tianming; Ding, Liqing; Jin, Huajia; Shi, Rong; Li, Yuanyuan; Wu, Jiasheng; Li, Yifei; Zhu, Li; Ma, Yueming

    2016-08-01

    A sensitive, specific, accurate HPLC-MS/MS method was developed and validated for the simultaneous quantification of catechin, epicatechin, liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin, piperine and glycyrrhetinic acid from Longhu Rendan pills in rat plasma. Chromatographic separation was performed with a Hypersil Gold C18 column using a gradient of methanol and 0.01% acetic acid containing 0.2 mm ammonium acetate as mobile phase. The analytes were quantified on a triple quadrupole mass spectrometer, operating in selected reaction monitoring mode and switching the electrospray ion source polarity between positive and negative modes in a single run. The calibration curves of catechin, epicatechin, liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin, piperine and glycyrrhetinic acid were linear over the concentration ranges of 5-2000, 5-2000, 0.5-200, 0.5-200, 0.25-100, 0.25-100, 0.025-10 and 0.50-200 ng mL(-1) , respectively. The intra- and inter-assay precisions and accuracies were <11.6 and 91.9-108.2%, respectively, for all analytes. Matrix effects for all analytes were between 88.2 and 114.2%. Stability testing showed that all analytes were stable in plasma at 24 °C for 3 h, at 4 °C for 24 h, after three freeze-thaw cycles, and at -80 °C for 15 days. The method was successfully applied to an in vivo study evaluating the pharmacokinetics of multiple nonvolatile compounds following intragastric administration of Longhu Rendan pills to rats. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. The effect of Zn-Al-hydrotalcites composited with calcium stearate and β-diketone on the thermal stability of PVC.

    PubMed

    Tong, Mengliang; Chen, Hongyan; Yang, Zhanhong; Wen, Runjuan

    2011-01-01

    A clean-route synthesis of Zn-Al-hydrotalcites (Zn-Al-LDHs) using zinc oxide and sodium aluminate solution has been developed. The as-obtained materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The effects of metal ions at different molar ratios on the performance of hydrotalcites were discussed. The results showed that the Zn-Al-hydrotalcites can be successfully synthesized at three different Zn/Al ratios of 3:1, 2:1 and 1:1. Thermal aging tests of polyvinyl chloride (PVC) mixed with Zn-Al-LDHs, calcium stearate (CaSt(2)) and β-diketone were carried out in a thermal aging test box by observing the color change. The results showed that Zn-Al-LDHs can not only enhance the stability of PVC significantly due to the improved capacity of HCl-adsorption but also increase the initial stability and ensure good-initial coloring due to the presence of the Zn element. The effects of various amounts of Zn-Al-LDHs, CaSt(2) and β-diketone on the thermal stability of PVC were discussed. The optimum composition was determined to be 0.1 g Zn-Al-LDHs, 0.15 g CaSt(2) and 0.25 g β-diketone in 5 g PVC.

  9. Use of surface energy distributions by inverse gas chromatography to understand mechanofusion processing and functionality of lactose coated with magnesium stearate.

    PubMed

    Das, Shyamal C; Zhou, Qi; Morton, David A V; Larson, Ian; Stewart, Peter J

    2011-07-17

    The purpose was to employ a new finite dilution approach to determine total surface energy distributions of mechanofused powders by inverse gas chromatography (IGC) to contribute to the understanding of their improved flow properties and to help optimise the magnesium stearate (MgSt) coating. Pharmatose 450M was mechanofused with between 0.1 and 8% (w/w) of MgSt. The non-polar, polar and total surface energies and work of cohesion at infinite dilution and the energy distributions at finite dilution were constructed using IGC. Brunauer-Emmet-Teller (BET) surface area and particle morphology were determined by IGC and scanning electron microscope, respectively. Surface energies determined at finite dilution appeared more consistent with the observed flow behaviour of mechanofused powders than comparative surface energy determination at infinite dilution. Polar and total surface energy distributions together with BET surface area measurements were the lowest when lactose was mechanofused with 1-2% MgSt (w/w). In conclusion, the surface energy distribution profiles measured at finite dilution were argued to be more informative and useful in reporting the surface energy changes during mechanofusion, optimising MgSt concentration in the mechanofusion process, and the flow behaviour of mechanofused powders.

  10. The Effect of Zn-Al-Hydrotalcites Composited with Calcium Stearate and β-Diketone on the Thermal Stability of PVC

    PubMed Central

    Tong, Mengliang; Chen, Hongyan; Yang, Zhanhong; Wen, Runjuan

    2011-01-01

    A clean-route synthesis of Zn-Al-hydrotalcites (Zn-Al-LDHs) using zinc oxide and sodium aluminate solution has been developed. The as-obtained materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The effects of metal ions at different molar ratios on the performance of hydrotalcites were discussed. The results showed that the Zn-Al-hydrotalcites can be successfully synthesized at three different Zn/Al ratios of 3:1, 2:1 and 1:1. Thermal aging tests of polyvinyl chloride (PVC) mixed with Zn-Al-LDHs, calcium stearate (CaSt2) and β-diketone were carried out in a thermal aging test box by observing the color change. The results showed that Zn-Al-LDHs can not only enhance the stability of PVC significantly due to the improved capacity of HCl-adsorption but also increase the initial stability and ensure good-initial coloring due to the presence of the Zn element. The effects of various amounts of Zn-Al-LDHs, CaSt2 and β-diketone on the thermal stability of PVC were discussed. The optimum composition was determined to be 0.1 g Zn-Al-LDHs, 0.15 g CaSt2 and 0.25 g β-diketone in 5 g PVC. PMID:21673921

  11. Formulation and evaluation of carvedilol melt-in-mouth tablet using mucoadhesive polymer and PEG-6-stearate as hydrophilic waxy binder

    PubMed Central

    Dangi, Amish Ashvinkumar; Zalodiya, Prakash Bhikhabhai

    2012-01-01

    Purpose: The demand for melt-in-mouth tablets (MMTs) has been rapidly growing during the last decade, especially for the elderly and children who have swallowing difficulties, to avoid first-pass metabolism and quick drug entry into the systemic circulation. Materials and Methods: In this work, a new approach has been tried to prepare MMTs using a hydrophilic waxy binder [polyethylene glycol (PEG)-6-stearate]. Carvedilol MMTs were prepared by direct compression method using different mucoadhesive polymers such as hydroxypropyl methylcellulose (HPMC), chitosan, and sodium carboxymethyl cellulose (Na-CMC) at various concentrations (range: 0.5–5%) to reduce the flushing action of saliva and to increase mucosal absorption. All the formulations were evaluated for various physiochemical parameters, and the formulations containing the maximum amount of polymer (F4, F7, and F10) were selected for further stability study. Results: The deaggregation time of the tablets was found to be rapid, and the dissolution test revealed that carvedilol was dissolved from the formulation within the compendia limits. This data confirmed that the polymer concentration (0.5–5%) was within acceptable limits. It was also concluded that avicel PH101, pearlitol SD 200, and croscarmellose sodium (CCS) were the appropriate excipients and formulated in the right proportion. Conclusion: As a result, mouth dissolving administration of carvedilol formulated with appropriate excipients and especially with chitosan seems a promising alternative to traditional routes. PMID:23580934

  12. A comparative study of glycerin fatty acid ester and magnesium stearate on the dissolution of acetaminophen tablets using the analysis of available surface area.

    PubMed

    Uchimoto, Takeaki; Iwao, Yasunori; Takahashi, Kana; Tanaka, Shoko; Agata, Yasuyoshi; Iwamura, Takeru; Miyagishima, Atsuo; Itai, Shigeru

    2011-08-01

    To study the effect of glycerin fatty acid ester (Poem TR-FB) concentrations on the dissolution rate of acetaminophen (APAP), the dissolution and disintegration behaviors of APAP tablets formulated using various lubricants were examined. The change over time in the available surface area of APAP (S(t)), which is in direct contact with solvent, was also analyzed using these dissolution data. In the dissolution tests, a retarded dissolution of APAP was not observed with TR-FB, whereas magnesium stearate (Mg-St), which is widely used as a lubricant, retarded the dissolution. However, no significant difference in the disintegration time between the two lubricants was observed. With regard to the time course of the S(t), Mg-St at 0.1% gave a maximum surface area value at 9.19 min (peak time); however, the profiles for APAP with Mg-St at greater than 0.5% showed downward curvature indicating a gradual decrease in surface area over time. Conversely, with TR-FB, even when its concentration was increased, the S(t) profile for APAP had a maximum value that was more than twice that of APAP with that of 0.5-3.0% of Mg-St. Scanning electron microscopy (SEM) observations showed that the differences in the dissolution rate and S(t) patterns between Mg-St and TR-FB could be explained by differences in extensibility deriving from their morphology. Therefore, it was concluded that TR-FB does not cause retardation of drug dissolution and may prove to be a superior alternative lubricant to Mg-St. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Conjugates of 18β-glycyrrhetinic acid derivatives with 3-(1H-benzo[d]imidazol-2-yl)propanoic acid as Pin1 inhibitors displaying anti-prostate cancer ability.

    PubMed

    Li, Kun; Ma, Tianyi; Cai, Jingjing; Huang, Min; Guo, Hongye; Zhou, Di; Luan, Shenglin; Yang, Jinyu; Liu, Dan; Jing, Yongkui; Zhao, Linxiang

    2017-08-04

    Twenty-six conjugates of 18β-glycyrrhetinic acid derivatives with 3-(1H-benzo[d]imidazol-2-yl)propanoic acid were designed and synthesized as Pin1 inhibitors. Most of these semi-synthetic compounds showed improved Pin1 inhibitory activity and anti-proliferative effects against prostate cancer cells as compared to 3-(1H-benzo[d]imidazol-2-yl)propanoic acid and GA. Compounds 10a and 12i were the most potent to inhibit growth of prostate cancer PC-3 with GI50 values of 7.80μM and 3.52μM, respectively. The enzyme inhibition ratio of nine compounds at 10μM was over 90%. Structure-activity relationships indicated that both appropriate structure at ring C of GA and suitable length of linker between GA skeleton and benzimidazole moiety had significant impact on improving activity. Western blot assay revealed that 10a decreased the level of cell cycle regulating protein cyclin D1. Thus, these compounds might represent a novel anti-proliferative agent working through Pin1 inhibition. Copyright © 2017. Published by Elsevier Ltd.

  14. Effects of Glycyrrhetinic Acid on GSH Synthesis Induced by Realgar in the Mouse Hippocampus: Involvement of System [Formula: see text], System [Formula: see text], MRP-1, and Nrf2.

    PubMed

    Wang, Yan-Lei; Chen, Mo; Huo, Tao-Guang; Zhang, Ying-Hua; Fang, Ying; Feng, Cong; Wang, Shou-Yun; Jiang, Hong

    2016-04-02

    Realgar, a type of mineral drug-containing arsenic, exhibits neurotoxicity. Brain glutathione (GSH) is crucial to protect the nervous system and to resist arsenic toxicity. Therefore, the main aim of this study was to explore the neurotoxic mechanisms of realgar and the protective effects of glycyrrhetinic acid (GA) by observing the effects of GA on the hippocampal GSH biosynthetic pathway after exposure to realgar. Institute of Cancer Research (ICR) mice were randomly divided into five groups: a control group, a GA control group, a realgar alone group, a low-dose GA intervention group, and a high-dose GA intervention group. Cognitive ability was tested using an object recognition task (ORT). The ultrastructures of the hippocampal neurons and synapses were observed. mRNA and protein levels of EAAT1, EAAT2, EAAT3, xCT, Nrf2, HO-1, γ-GCS (GCLC, GCLM), and MRP-1 were measured, as was the cellular localization of EAAT3, xCT, MRP-1, and Nrf2. The levels of GSH in the hippocampus, the levels of glutamate (Glu) and cysteine (Cys) in the extracellular fluid of hippocampal CA1 region, and the levels of active sulfur in the brain were also investigated. The results indicate that realgar lowered hippocampal GSH levels, resulting in ultrastructural changes in hippocampal neurons and synapses and deficiencies in cognitive ability, ultimately inducing neurotoxicity. GA could trigger the expression of Nrf2, HO-1, EAAT1, EAAT2, EAAT3, xCT, MRP-1, GCLC, and GCLM. Additionally, the expression of γ-GT and the supply levels of Glu and Cys increased, ultimately causing a significant increase in hippocampal GSH to alleviate realgar-induced neurotoxicity. In conclusion, the findings from our study indicate that GA can antagonize decreased brain GSH levels induced by realgar and can lessen the neurotoxicity of realgar.

  15. Glycyrrhizic acid and 18β-glycyrrhetinic acid modulate lipopolysaccharide-induced inflammatory response by suppression of NF-κB through PI3K p110δ and p110γ inhibitions.

    PubMed

    Wang, Chung-Yi; Kao, Tzu-Chien; Lo, Wen-Hsieh; Yen, Gow-Chin

    2011-07-27

    The roots and rhizomes of licorice ( Glycyrrhia ) species have been used extensively as natural sweeteners and herbal medicines. The aim of this work was to determine the in vitro anti-inflammatory effects of glycyrrhizic acid (GA) and 18β-glycyrrhetinic acid (18βGA) from licorice in a lipopolysaccharide (LPS)-stimulated macrophage model. The results showed that treatment with 25-75 μM GA or 18βGA did not reduce RAW 264.7 cell viability but did significantly inhibit the production of LPS-induced nitric oxide (NO), prostaglandin E(2) (PGE(2)), and intracellular reactive oxygen species (ROS). Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR) analyses revealed that GA and 18βGA significantly reduced the protein and mRNA levels of iNOS and COX-2 in LPS-induced macrophages. Both GA and 18βGA inhibited the activation of NF-κB and the activities of phosphoinositide-3-kinase (PI3K) p110δ and p110γ isoforms and then reduced the production of LPS-induced tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β in a dose-dependent manner. In conclusion, these results indicate that GA and 18βGA may provide an anti-inflammatory effect by attenuating the generation of excessive NO, PGE(2), and ROS and by suppressing the expression of pro-inflammatory genes through the inhibition of NF-κB and PI3K activity. Thus, the results suggest that GA and 18βGA might serve as potential agents for the treatment of inflammatory-mediated diseases.

  16. Inhibition of protein kinase C α/βII and activation of c-Jun NH2-terminal kinase mediate glycyrrhetinic acid induced apoptosis in non-small cell lung cancer NCI-H460 cells.

    PubMed

    Song, Junho; Ko, Hyun-suk; Sohn, Eun Jung; Kim, Bonglee; Kim, Jung Hyo; Kim, Hee Jeong; Kim, Chulwoo; Kim, Jai-eun; Kim, Sung-Hoon

    2014-02-15

    Though glycyrrhetinic acid (GA) from Glycyrrhiza glabra was known to exert antioxidant, antifilarial, hepatoprotective, anti-inflammatory and anti-tumor effects, the antitumor mechanism of GA was not clearly elucidated in non-small cell lung cancer cells (NSCLCCs). Thus, in the present study, the underlying apoptotic mechanism of GA was examined in NCI-H460 NSCLCCs. GA significantly suppressed the viability of NCI-H460 and A549 non-small lung cancer cells. Also, GA significantly increased the sub G1 population by cell cycle analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells in a concentration dependent manner in NCI-H460 non-small lung cancer cells. Consistently, GA cleaved poly (ADP-ribosyl) polymerase (PARP), caspase 9/3, attenuated the expression of Bcl-XL, Bcl-2, Cyclin D1 and Cyclin E in NCI-H460 cells. Interestingly, GA attenuated the phosphorylation of protein kinase C (PKC) α/βII and extracellular activated protein kinase (ERK) as well as activated the phosphorylation of PKC δ and c-Jun NH2-terminal kinase in NCI-H460 cells. Conversely, PKC promoter phorbol 12-myristate 13-acetate (PMA) and JNK inhibitor SP600125 reversed the cleavages of caspase 3 and PARP induced by GA in NCI-H460 cells. Overall, our findings suggest that GA induces apoptosis via inhibition of PKC α/βII and activation of JNK in NCI-H460 non-small lung cancer cells as a potent anticancer candidate for lung cancer treatment.

  17. Glycyrrhetinic acid attenuates lipopolysaccharide-induced fulminant hepatic failure in d-galactosamine-sensitized mice by up-regulating expression of interleukin-1 receptor-associated kinase-M.

    PubMed

    Yin, Xinru; Gong, Xia; Zhang, Li; Jiang, Rong; Kuang, Ge; Wang, Bin; Chen, Xinyu; Wan, Jingyuan

    2017-04-01

    Glycyrrhetinic acid (GA), the main active ingredient of licorice, reportedly has anti-inflammatory and hepatoprotective properties, but its molecular mechanisms remain be elusive. In the present study, Balb/c mice were pretreated with GA (10, 30, or 100mg/kg) 1h before lipopolysaccharide (LPS)/d-galactosamine (D-GalN) administration. In other in vitro experiment, RAW264.7 macrophages were pretreated with GA before LPS exposure. The mortality, hepatic tissue histology, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed. Toll like receptor 4 (TLR4), interleukin-1 receptor-associated kinases (IRAKs), activation of mitogen-activated protein kinases (MAPKs) and NF-κB, and production of TNF-α were assessed by flow cytometry, western blotting, and enzyme-linked immunosorbent assay (ELISA), respectively. Our results showed that pretreatment with GA protected mice against LPS/D-GalN-induced fulminant hepatic failure (FHF), including a dose-dependent alleviation of mortality and ALT/AST elevation, ameliorating hepatic pathological damage, and decreasing TNF-α release. Moreover, GA inhibited LPS-induced activation of MAPKs and NF-κB in response to LPS, but the expression of TLR4 was not affected in vivo and in vitro. Notably, GA pretreatment in vivo suppressed IRAK-1 activity while inducing IRAK-M expression. Silencing of IRAK-M expression with siRNA blocked these beneficial effects of GA on the activation of MAPKs and NF-κB as well as TNF-α production in LPS-primed macrophages. Taken together, we conclude that GA could prevent LPS/D-GalN-induced FHF. The underlying mechanisms may be related to up-regulation of IRAK-M, which in turn caused deactivation of IRAK-1 and subsequent MAPKs and NF-κB, resulting in inhibiting TNF-α production.

  18. Anti-inflammatory and hepatoprotective effects of glycyrrhetinic acid on CCl4-induced damage in precision-cut liver slices from Jian carp (Cyprinus carpio var. jian) through inhibition of the nf-kƁ pathway.

    PubMed

    Cao, Liping; Ding, Weidong; Jia, Rui; Du, Jingliang; Wang, Tao; Zhang, Chunyun; Gu, Zhengyan; Yin, Guojun

    2017-03-10

    In order to evaluate the antioxidant and anti-inflammatory effects of glycyrrhetinic acid (GA) on carbon tetrachloride (CCl4)-induced damage in precision-cut liver slices (PCLS) from Jian carp (Cyprinus carpio. Jian), an acute liver damage model was established in this study. The viability of PCLS, levels of anti-oxidases in liver homogenates, expression of inflammation-related genes including nuclear factor-κB (nf-κB)/c-rel, inducible nitric oxide synthase (inos), interleukin-1β (il-1β), interleukin-6 (il-6) and interleukin-8 (il-8), and protein levels of (nf-κB)/c-rel in liver tissues were measured. The results showed that pretreatment of PCLS with GA at 5 and 10 μg/mL for 6 h significantly inhibited the cytotoxicity of CCl4. GA attenuated CCl4-induced oxidative stress in PCLS through promoting the recovery of superoxide dismutase (SOD) and glutathione (GSH) levels, and inhibiting malondialdehyde (MDA) synthesis. In inflammatory response, GA at both 5 and 10 μg/mL significantly inhibited the increase in mRNA levels of inflammatory cytokines including nf-kƁ/c-rel, inos, il-1β, il-6 and il-8, and the protein level of Nf-kƁ/C-rel induced by CCl4. Furthermore, treatment with pyrrolyl dithiocarbamate (PDTC, 4 μg/mL), an inhibitor of nuclear transcription factor nf-kB, significantly inhibited nf-kB levels, and transcription of downstream cytokines inos, il-1β, il-6 and il-8, also the viability of PCLS was significantly increased. These results indicated that GA suppressed inflammation and reduced cytotoxicity by inhibiting the nf-kƁ signaling pathway, and plays a role in liver protection.

  19. Final report of the amended safety assessment of Glyceryl Laurate, Glyceryl Laurate SE, Glyceryl Laurate/Oleate, Glyceryl Adipate, Glyceryl Alginate, Glyceryl Arachidate, Glyceryl Arachidonate, Glyceryl Behenate, Glyceryl Caprate, Glyceryl Caprylate, Glyceryl Caprylate/Caprate, Glyceryl Citrate/Lactate/Linoleate/Oleate, Glyceryl Cocoate, Glyceryl Collagenate, Glyceryl Erucate, Glyceryl Hydrogenated Rosinate, Glyceryl Hydrogenated Soyate, Glyceryl Hydroxystearate, Glyceryl Isopalmitate, Glyceryl Isostearate, Glyceryl Isostearate/Myristate, Glyceryl Isostearates, Glyceryl Lanolate, Glyceryl Linoleate, Glyceryl Linolenate, Glyceryl Montanate, Glyceryl Myristate, Glyceryl Isotridecanoate/Stearate/Adipate, Glyceryl Oleate SE, Glyceryl Oleate/Elaidate, Glyceryl Palmitate, Glyceryl Palmitate/Stearate, Glyceryl Palmitoleate, Glyceryl Pentadecanoate, Glyceryl Polyacrylate, Glyceryl Rosinate, Glyceryl Sesquioleate, Glyceryl/Sorbitol Oleate/Hydroxystearate, Glyceryl Stearate/Acetate, Glyceryl Stearate/Maleate, Glyceryl Tallowate, Glyceryl Thiopropionate, and Glyceryl Undecylenate.

    PubMed

    2004-01-01

    The safety of 43 glyceryl monoesters listed as cosmetic ingredients was reviewed in a safety assessment completed in 2000. Additional safety test data pertaining to Glyceryl Rosinate and Glyceryl Hydrogenated Rosinate were received and served as the basis for this amended report. Glyceryl monoesters are used mostly as skin-conditioning agents--emollients and/or surfactant--emulsifying agents in cosmetics. The following 20 glyceryl monoesters are currently reported to be used in cosmetics: Glyceryl Laurate, Glyceryl Alginate, Glyceryl Arachidonate, Glyceryl Behenate, Glyceryl Caprylate, Glyceryl Caprylate/Caprate, Glyceryl Cocoate, Glyceryl Erucate, Glyceryl Hydroxystearate, Glyceryl Isostearate, Glyceryl Lanolate, Glyceryl Linoleate, Glyceryl Linolenate, Glyceryl Myristate, Glyceryl Oleate/Elaidate, Glyceryl Palmitate, Glyceryl Polyacrylate, Glyceryl Rosinate, Glyceryl Stearate/Acetate, and Glyceryl Undecylenate. Concentration of use data received from the cosmetics industry in 1999 indicate that Glyceryl Monoesters are used at concentrations up to 12% in cosmetic products. Glyceryl Monoesters are not pure monoesters, but are mostly mixtures with mono-, di-, and tri-esters. The purity of commercial and conventional Monoglyceride (Glyceryl Monoester) is a minimum of 90%. Glyceryl Monoesters (monoglycerides) are metabolized to free fatty acids and glycerol, both of which are available for the resynthesis of triglycerides. Glyceryl Laurate enhanced the penetration of drugs through cadaverous skin and hairless rat skin in vitro and has been described as having a wide spectrum of antimicrobial activity. A low-grade irritant response was observed following inhalation of an aerosol containing 10% Glyceryl Laurate by test animals. Glyceryl monoesters have little acute or short-term toxicity in animals, and no toxicity was noted following chronic administration of a mixture consisting mostly of glyceryl di- and mono- esters. Glyceryl Laurate did have strong hemolytic

  20. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 64, which is incorporated... Codex are available from the National Academy Press, 2101 Constitution Ave. NW., Washington, DC...

  1. 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

    : 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. Some of these are not currently in use, but would be considered safe if used at concentrations similar to those glyceryl triesters that are in use as cosmetic ingredients.

  2. 21 CFR 178.3690 - Pentaerythritol adipate-stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. (4) Iodine number not to exceed 2 as determined by Iodine Absorption Number, Hanus Method, of the “Official Methods...

  3. 21 CFR 178.3690 - Pentaerythritol adipate-stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. (4) Iodine number not to exceed 2 as determined by Iodine Absorption Number, Hanus Method, of the “Official Methods...

  4. 21 CFR 178.3690 - Pentaerythritol adipate-stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. (4) Iodine number not to exceed 2 as determined by Iodine Absorption Number, Hanus Method, of the “Official Methods...

  5. 21 CFR 178.3690 - Pentaerythritol adipate-stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. (4) Iodine number not to exceed 2 as determined by Iodine Absorption Number, Hanus Method, of the “Official Methods...

  6. Synthesis of bis-phosphono stearates from methyl linoleate and dialkyl phosphites

    USDA-ARS?s Scientific Manuscript database

    Linoleic acid is the major component of soybean, corn, sunflower, and other commodity oils. This makes methyl linoleate a better model than methyl oleate as a compound for investigating the chemical modification of vegetable oils for industrial purposes. In the current work, we report the reaction o...

  7. Lubrication properties of potential alternative lubricants, glycerin fatty acid esters, to magnesium stearate.

    PubMed

    Uchimoto, Takeaki; Iwao, Yasunori; Ikegami, Yuki; Murata, Takashi; Sonobe, Takashi; Miyagishima, Atsuo; Itai, Shigeru

    2010-02-15

    To study the usefulness of glycerin fatty acid ester Poem TR-FB (TR-FB) and Poem TR-HB (TR-HB) as lubricants, pressure transmission ratio, ejection force, disintegration time, and tensile strength were measured at different concentrations and mixing times for granules and tablets. When each lubricant was mixed at 0.1-3.0%, the increase in the pressure transmission ratio that was equal to or greater than that of Mg-St as well as the reduction in the ejection force was observed at a low concentration in both TR-FB and TR-HB, proving that they have excellent lubrication performance. The granules that were lubricated with TR-FB and TR-HB at even low concentration of 0.4% showed a more stable and sufficiently lower ejection force than with Mg-St from the first tablet after the start of compression. When they were mixed for 5-60 min, while the mixture with Mg-St showed a low pressure transmission ratio of 82% and a high ejection force of 500 N in the first tablet even when the mixing time was 60 min, a high pressure transmission ratio and a low ejection force were observed in TR-FB and TR-HB from the first tablet after mixing for 5-60 min, and these were maintained thereafter. As for the disintegration time and the tensile strength, a prolonged disintegration time and a decreased tensile strength, which are disadvantages of Mg-St, were not observed in TR-FB and TR-HB. Based on these results, it was concluded that TR-FB and TR-HB are useful as alternative lubricants to Mg-St. Copyright 2009 Elsevier B.V. All rights reserved.

  8. 21 CFR 178.3505 - Glyceryl tri-(12-acetoxy-stearate).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... provisions of this section. (a) The additive is applied to the 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...

  9. 21 CFR 178.3505 - Glyceryl tri-(12-acetoxy-stearate).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 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 contact...

  10. 21 CFR 178.3505 - Glyceryl tri-(12-acetoxy-stearate).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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 contact...

  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 contact...

  12. Interaction of the acid soap of triethanolamine stearate and stearic acid with water.

    PubMed

    Zhu, S; Pudney, P D A; Heppenstall-Butler, M; Butler, M F; Ferdinando, D; Kirkland, M

    2007-02-08

    Stearic acid and triethanolamine (TEA) in a molar ratio of 2:1 were mixed in aqueous solution at 80 degrees C and subsequently cooled to ambient temperature. The structural evolution of the resultant sample during storage was characterized by using light microscopy, Cryo-SEM, differential scanning calorimetery, pH, infrared spectroscopy, elemental analysis, and simultaneous small and wide-angle X-ray diffraction. It was found that a lamellar liquid crystalline phase was formed when stearic acid and TEA solution were mixed at 80 degrees C and multilamellar spheres of a few microns diameter were formed initially after cooling. A hydrolysis reaction (i.e., the reverse reaction of neutralization between stearic acid and TEA) occurred thereafter that caused the breakdown of the lamellar gel phase and the formation of platelet stearic acid crystals. Three polymorphs of stearic acid (defined following previous work as the A, C, and E forms) were formed as the result of hydrolysis reaction, which gave rise to a strong optically pearlescent appearance.

  13. Interfacial, stability and rheological study of microbubbles coated with a monostearin/monopalmitin-rich food emulsifier and PEG40 stearate

    NASA Astrophysics Data System (ADS)

    Shen, Yuyi

    Micron-scale bubbles (microbubbles) are of considerable interest in environmental, biomedical, and food sciences. The low cost food emulsifiers, which are used to stabilize the gas core of the microbubble, consist of a mixture of monoglycerides, diglycerides and sodium steroyl lactylate in combination with polyethylene glycol (PEG) 40 sterate. Langmuir trough methods and fluorescence microscopy were combined to investigate the surface tension, interfacial elastic modulus, phase behavior and microstructure of monolayer shells coating these microbubbles. Polydisperse coated microbubbles can be generated using a probe sonication technique. The dissolution behavior of a microbubble in different unsaturated media was studied using a fluorescence microscope. These dissolution behaviors, involving the buckling and rupture of the coated monolayer, can be explained by the phase behavior of emulsifiers and their roles in the stabilization of microbubbles in aqueous systems. Nearly monodispersed populations of microbubbles ranged in 120--200mum were produced using flow focusing Technique. Sufficient short-term stability in size allows the rheological properties of microbubble suspension to be obtained by rheometer. The effect of shearing on the bubble sizes is investigated. There results show that the microbubble suspensions are viscoelastic and exhibit power law behavior. The relationship between the air fraction of the suspension and fluid rheology is determined.

  14. The role of stearate attachment to the hemagglutinin-esterase-fusion glycoprotein HEF of influenza C virus.

    PubMed

    Wang, Mingyang; Ludwig, Kai; Böttcher, Christoph; Veit, Michael

    2016-05-01

    The only spike of influenza C virus, the hemagglutinin-esterase-fusion glycoprotein (HEF) combines receptor binding, receptor hydrolysis and membrane fusion activities. Like other hemagglutinating glycoproteins of influenza viruses HEF is S-acylated, but only with stearic acid at a single cysteine located at the cytosol-facing end of the transmembrane region. Previous studies established the essential role of S-acylation of hemagglutinin for replication of influenza A and B virus by affecting budding and/or membrane fusion, but the function of acylation of HEF was hitherto not investigated. Using reverse genetics we rescued a virus containing non-stearoylated HEF, which was stable during serial passage and showed no competitive fitness defect, but the growth rate of the mutant virus was reduced by one log. Deacylation of HEF does neither affect the kinetics of its plasma membrane transport nor the protein composition of virus particles. Cryo-electron microscopy showed that the shape of viral particles and the hexagonal array of spikes typical for influenza C virus were not influenced by this mutation indicating that virus budding was not disturbed. However, the extent and kinetics of haemolysis were reduced in mutant virus at 37°C, but not at 33°C, the optimal temperature for virus growth, suggesting that non-acylated HEF has a defect in membrane fusion under suboptimal conditions.

  15. 21 CFR 181.29 - Stabilizers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate...-, and tripotassium citrate. Potassium oleate. Potassium stearate. Sodium pyrophosphate. Sodium stearate. Sodium tetrapyrophosphate. Stannous stearate (not to exceed 50 parts per million tin as a migrant in...

  16. 21 CFR 181.29 - Stabilizers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate...-, and tripotassium citrate. Potassium oleate. Potassium stearate. Sodium pyrophosphate. Sodium stearate. Sodium tetrapyrophosphate. Stannous stearate (not to exceed 50 parts per million tin as a migrant in...

  17. 21 CFR 181.29 - Stabilizers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate...-, and tripotassium citrate. Potassium oleate. Potassium stearate. Sodium pyrophosphate. Sodium stearate. Sodium tetrapyrophosphate. Stannous stearate (not to exceed 50 parts per million tin as a migrant in...

  18. 21 CFR 181.29 - Stabilizers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate...-, and tripotassium citrate. Potassium oleate. Potassium stearate. Sodium pyrophosphate. Sodium stearate. Sodium tetrapyrophosphate. Stannous stearate (not to exceed 50 parts per million tin as a migrant in...

  19. 21 CFR 181.29 - Stabilizers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate. Calcium ricinoleate... citrate. Potassium oleate. Potassium stearate. Sodium pyrophosphate. Sodium stearate. Sodium...

  20. Enhancement of nose-to-brain delivery of hydrophilic macromolecules with stearate- or polyethylene glycol-modified arginine-rich peptide.

    PubMed

    Kanazawa, Takanori; Kaneko, Mami; Niide, Takaki; Akiyama, Fuminari; Kakizaki, Shino; Ibaraki, Hisako; Shiraishi, Shunsuke; Takashima, Yuuki; Suzuki, Toyofumi; Seta, Yasuo

    2017-09-15

    Recently, nose-to-brain delivery is a highly versatile route, which, in combination with novel drugs being developed for treating intractable CNS diseases, is a promising approach for the treatment of disorders. Furthermore, nano-sized drug carriers may improve nose-to-brain drug delivery by their capability to increase the transmucosal penetration of the drugs across nasal mucosal tissue barrier. However, there is still not enough information regarding mechanism of absorption pathway from nasal cavity to brain using nanocarriers. In this study, to investigate the nose-to-brain transport pathway using nanocarriers, the distribution in whole brain, nasal mucosa, and trigeminal nerve after intranasal administration of two kinds of nanocarriers which have hydrophobic or hydrophilic moiety. We used CHHRRRRHHC peptide (CH2R4H2C) as basic peptide carriers, and modified with stearic acid (STR) as a hydrophobic moiety (STR-CH2R4H2C) or polyethylene glycol (PEG)-based block copolymer (PEG-PCL) as hydrophilic moiety (PEG-PCL-CH2R4H2C). The nose-to-brain drug delivery can be improved by using STR-CH2R4H2C and PEG-PCL-CH2R4H2C as carriers. Specifically, hydrophobic STR-CH2R4H2C is more suitable for the transport of drugs targeting the forebrain, while PEG-PCL-modified CH2R4H2C is more suitable for transporting drugs targeting the hindbrain or whole brain tissue. In conclusion, the results of this study support the possibility that drug delivery pathways can be controlled depending on the properties of different carrier complexes. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. LUBRICATING AND SIZING AGENT FOR GLASS FIBER,

    DTIC Science & Technology

    GLASS TEXTILES, SURFACE PROPERTIES), (*LUBRICANTS, GLASS TEXTILES), FIBERS , POLYVINYL ALCOHOL, STEARATES, CHROMIUM COMPOUNDS, ALUMINUM COMPOUNDS, MIXTURES, LACTATES, TITANIUM COMPOUNDS, MECHANICAL PROPERTIES, USSR

  2. Selective use of palmitic acid over stearic acid for synthesis of phosphatidylcholine and phosphatidylglycerol in lung

    SciTech Connect

    Tsao, F.H.

    1986-11-01

    The incorporation of (/sup 3/H)palmitic acid and (/sup 14/C)stearic acid into phospholipids in rabbit lung tissue was studied. Under equal molar concentrations of palmitate and stearate, palmitate was incorporated to the 1- and 2-positions of phosphatidylcholine (PC) and phosphatidylglycerol (PG) 2-3 times more than stearate. By contrast, palmitate was 30% less than stearate in phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine. These results suggest that preferential utilization of palmitate over stearate, rather than substrate availability, determines the high content of palmitoyl at the 1- and 2-positions of PC and PG in lung.

  3. 21 CFR 177.2410 - Phenolic resins in molded articles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...: Asbestos fiber Barium hydroxide For use as catalyst. Calcium stearate For use as lubricant. Carbon black (channel process) Diatomaceous earth Glass fiber Hexamethylenetetramine For use as curing agent....

  4. 21 CFR 177.2410 - Phenolic resins in molded articles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...: Asbestos fiber Barium hydroxide For use as catalyst. Calcium stearate For use as lubricant. Carbon black (channel process) Diatomaceous earth Glass fiber Hexamethylenetetramine For use as curing agent....

  5. 21 CFR 177.2410 - Phenolic resins in molded articles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... produced when phenol is made to react with styrene in the presence of sulfuric acid catalyst. (2) Aldehydes...: Asbestos fiber Barium hydroxide For use as catalyst. Calcium stearate For use as lubricant. Carbon black... Oxalic acid For use as catalyst. Zinc stearate For use as lubricant. (c) The finished food-contact...

  6. 21 CFR 177.2410 - Phenolic resins in molded articles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... produced when phenol is made to react with styrene in the presence of sulfuric acid catalyst. (2) Aldehydes...: Asbestos fiber Barium hydroxide For use as catalyst. Calcium stearate For use as lubricant. Carbon black... Oxalic acid For use as catalyst. Zinc stearate For use as lubricant. (c) The finished food-contact...

  7. Ionic liquid 1-butyl-3-methylimidazolium cyanamide (bmim [dca]) as a solvent and catalyst for acylation of maltodextrin

    USDA-ARS?s Scientific Manuscript database

    We have found a novel method to prepare maltodextrin stearate with DS upto 0.60 in 90% yields from maltodextrin in IL bmim[dca] reacted with vinyl stearate or stearic acid. In this work we have demonstrated that IL could simultaneously act as a solvent and as a catalyst for reaction of maltodextrin...

  8. Ionic Liquid as a Solvent and Catalyst for Acylation of Maltodextrin

    USDA-ARS?s Scientific Manuscript database

    Catalyst-free esterification of maltodextrin was carried out in ionic liquid. Stearate esters of maltodextrin were obtained in various degree of substitution (DS) when vinyl stearate or stearic acid was heated with maltodextrin in ionic liquid, 1-butyl-3-methylimidazolium cyanamide (bmim[dca]). Re...

  9. The coating and the encapsulation of an interactive powder mixture and its application to sustained release preparations.

    PubMed

    Yoshizawa, H; Koishi, M

    1990-10-01

    Fine cohesive isoprenaline HCl particles adhered to the surface of coarser potato starch particles to form interactive mixtures. These were coated with magnesium stearate by dry mixing. To check if there was a lowering of homogeneity in the latter stage, the degree of mixing was investigated before and after adding magnesium stearate. The surface appearance of magnesium stearate-coated interactive mixtures became smoother as mixing time increased or the temperature of the powder bed during mixing was raised. Ultimately, the magnesium stearate encapsulated the particles of interactive mixture. The coated interactive mixtures improved sustained release of isoprenaline HCl over the starch mixtures alone, the effect depending on the density of the magnesium stearate. Only in encapsulated mixtures was the release rate of drug decreased as the amount of magnesium stearate increased. The release of isoprenaline HCl from the interactive mixtures followed first-order kinetics. A linear relationship existed between the first-order rate constant and the reciprocal thickness of the magnesium stearate film, indicating a diffusion-controlled system with the film having some pores.

  10. Preparation and Characterization of Polyhydroxybutyrate/Polycaprolactone Nanocomposites

    PubMed Central

    Liau, Cha Ping; Bin Ahmad, Mansor; Shameli, Kamyar; Yunus, Wan Md Zin Wan

    2014-01-01

    Polyhydroxybutyrate (PHB)/polycaprolactone (PCL)/stearate Mg-Al layered double hydroxide (LDH) nanocomposites were prepared via solution casting intercalation method. Coprecipitation method was used to prepare the anionic clay Mg-Al LDH from nitrate salt solution. Modification of nitrate anions by stearate anions between the LDH layers via ion exchange reaction. FTIR spectra showed the presence of carboxylic acid (COOH) group which indicates that stearate anions were successfully intercalated into the Mg-Al LDH. The formation of nanocomposites only involves physical interaction as there are no new functional groups or new bonding formed. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the mixtures of nanocomposites are intercalated and exfoliated types. XRD results showed increasing of basal spacing from 8.66 to 32.97 Å in modified stearate Mg-Al LDH, and TEM results revealed that the stearate Mg-Al LDH layers are homogeneously distributed in the PHB/PCL polymer blends matrix. Enhancement in 300% elongation at break and 66% tensile strength in the presence of 1.0 wt % of the stearate Mg-Al LDH as compare with PHB/PCL blends. Scanning electron microscopy (SEM) proved that clay improves compatibility between polymer matrix and the best ratio 80PHB/20PCL/1stearate Mg-Al LDH surface is well dispersed and stretched before it breaks. PMID:24600329

  11. Modification of composition of a nanoemulsion with different cholesteryl ester molecular species: Effects on stability, peroxidation, and cell uptake

    PubMed Central

    Almeida, Cristina P; Vital, Carolina G; Contente, Thais C; Maria, Durvanei A; Maranhão, Raul C

    2010-01-01

    Purpose: Use of lipid nanoemulsions as carriers of drugs for therapeutic or diagnostic purposes has been increasingly studied. Here, it was tested whether modifications of core particle constitution could affect the characteristics and biologic properties of lipid nanoemulsions. Methods: Three nanoemulsions were prepared using cholesteryl oleate, cholesteryl stearate, or cholesteryl linoleate as main core constituents. Particle size, stability, pH, peroxidation of the nanoemulsions, and cell survival and uptake by different cell lines were evaluated. Results: It was shown that cholesteryl stearate nanoemulsions had the greatest particle size and all three nanoemulsions were stable during the 237-day observation period. The pH of the three nanoemulsion preparations tended to decrease over time, but the decrease in pH of cholesteryl stearate was smaller than that of cholesteryl oleate and cholesteryl linoleate. Lipoperoxidation was greater in cholesteryl linoleate than in cholesteryl oleate and cholesteryl stearate. After four hours’ incubation of human umbilical vein endothelial cells (HUVEC) with nanoemulsions, peroxidation was minimal in the presence of cholesteryl oleate and more pronounced with cholesteryl linoleate and cholesteryl stearate. In contrast, macrophage incubates showed the highest peroxidation rates with cholesteryl oleate. Cholesteryl linoleate induced the highest cell peroxidation rates, except in macrophages. Uptake of cholesteryl oleate nanoemulsion by HUVEC and fibroblasts was greater than that of cholesteryl linoleate and cholesteryl stearate. Uptake of the three nanoemulsions by monocytes was equal. Uptake of cholesteryl oleate and cholesteryl linoleate by macrophages was negligible, but macrophage uptake of cholesteryl stearate was higher. In H292 tumor cells, cholesteryl oleate showed the highest uptakes. HUVEC showed higher survival rates when incubated with cholesteryl stearate and smaller survival with cholesteryl linoleate. H292

  12. One-step process for the fabrication of superhydrophobic surfaces with easy repairability

    NASA Astrophysics Data System (ADS)

    Li, Jian; Wan, Hongqi; Ye, Yinping; Zhou, Huidi; Chen, Jianmin

    2012-01-01

    A simple technique for fabrication of superhydrophobic surfaces was developed by spraying copper stearate suspension on various substrates. The copper stearate suspension is prepared by the reaction of copper acetate and stearic acid in ethanol solution. The as-prepared surfaces exhibit both superhydrophobicity and self-cleaning properties. When the superhydrophobic surfaces were destroyed, the damaged surfaces could be easily repaired by spraying the copper stearate suspension on the wrecked surfaces again, and the superhydrophobicity of the surfaces was regenerated at the same time.

  13. [Quality standards of effervescent granules for the treatment of cold pain].

    PubMed

    Sun, X; Zhang, Z; Liu, Z; Zhang, W

    1995-01-01

    Thin layer chromatography was performed to identify the ingredients of Effervescent Granules for arresting cold pain (Hantongding Paoteng Chongji). The limited doses of aconitine, granularity, moisture, acidity, sugar content, etc. were detected, and the contents of paeoniflorin, glycyrrhetinic acid and total alkaloids were determined. Thus, the quality standards for pharmaceutical preparation were preliminarily worked out.

  14. Selective solid-phase extraction of a triterpene acid from a plant extract by molecularly imprinted polymer.

    PubMed

    Claude, Bérengère; Morin, Philippe; Lafosse, Michel; Belmont, Anne-Sophie; Haupt, Karsten

    2008-04-15

    A molecularly imprinted polymer (MIP) has been prepared by a thermal polymerisation method using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent, chloroform as porogenic solvent and an oleanane triterpene compound (18-beta-glycyrrhetinic acid) as imprinted molecule (template). Equilibrium ligand binding experiments were done to assess the performance of the MIP relative to non-imprinted polymer (NIP). After optimisation of SPE protocol (CHCl3 as washing solvent and MeOH as elution solvent), successful imprinting was confirmed by comparison of the recoveries between NIP (5%) and MIP (97%) cartridges. The binding capacity of the MIP for 18-beta-glycyrrhetinic acid was determined to be 0.94 mg g(-1). Four structurally related oleanane triterpenes (18-alpha-glycyrrhetinic acid, oleanolic acid, echinocystic acid, erythrodiol) were selected to assess the MIP selectivity. Experimental data illustrated the influence of functional groups on the triterpene skeleton. The MIP was applied to the solid-phase extraction of triterpenoids from a plant extract prior HPLC analysis. However, CHCl3 was replaced by ACN during the washing step in order to suppress non-specific interactions due to polar matrix components. A selective extraction of 18-beta-glycyrrhetinic acid from hydrolyzed extract of liquorice roots was achieved with a good extraction yield (98%).

  15. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... anticaking ingredients referred to in paragraph (a) of this section are: (1) Aluminum calcium silicate. (2) Calcium silicate. (3) Calcium stearate. (4) Magnesium silicate. (5) Tricalcium phosphate. (c)(1) The...

  16. 21 CFR 177.2410 - Phenolic resins in molded articles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the presence of sulfuric acid catalyst. (2) Aldehydes: Acetaldehyde. Formaldehyde. Paraldehyde. (b... catalyst. Calcium stearate For use as lubricant. Carbon black (channel process) Diatomaceous earth Glass fiber Hexamethylenetetramine For use as curing agent. Mica Oxalic acid For use as catalyst....

  17. Viscosity Depressants for Coal Liquefaction

    NASA Technical Reports Server (NTRS)

    Kalfayan, S. H.

    1983-01-01

    Proposed process modification incorporates viscosity depressants to prevent coal from solidifying during liquefaction. Depressants reduce amount of heat needed to liquefy coal. Possible depressants are metallic soaps, such as stearate, and amides, such as stearamide and dimer acid amides.

  18. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... anticaking ingredients referred to in paragraph (a) of this section are: (1) Aluminum calcium silicate. (2) Calcium silicate. (3) Calcium stearate. (4) Magnesium silicate. (5) Tricalcium phosphate. (c)(1)...

  19. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... anticaking ingredients referred to in paragraph (a) of this section are: (1) Aluminum calcium silicate. (2) Calcium silicate. (3) Calcium stearate. (4) Magnesium silicate. (5) Tricalcium phosphate. (c)(1)...

  20. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... of this chapter Dioctyl phthalate For use as lubricant. Hexamethylenetetramine For use only as polymerization reaction control agent. Phthalic acid anhydride Do. Zinc stearate For use as lubricant. (c)...

  1. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... of this chapter Dioctyl phthalate For use as lubricant. Hexamethylenetetramine For use only as polymerization reaction control agent. Phthalic acid anhydride Do. Zinc stearate For use as lubricant. (c)...

  2. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... of this chapter Dioctyl phthalate For use as lubricant. Hexamethylenetetramine For use only as polymerization reaction control agent. Phthalic acid anhydride Do. Zinc stearate For use as lubricant. (c)...

  3. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... of this chapter Dioctyl phthalate For use as lubricant. Hexamethylenetetramine For use only as polymerization reaction control agent. Phthalic acid anhydride Do. Zinc stearate For use as lubricant. (c)...

  4. Preparation of superhydrophobic and UV blocking cotton fabric via sol-gel method and self-assembly

    NASA Astrophysics Data System (ADS)

    Pan, Chengyu; Shen, Li; Shang, Songmin; Xing, Yanjun

    2012-10-01

    Superhydrophobic surface has been successfully prepared on cotton substrates with inexpensive and ordinary raw materials, Al(NO3)3 and sodium stearate (C17H35COONa). Such surfaces were obtained first by dip-coating the nano-Al sol, then the surface of the Al coating was modified with sodium stearate, to gain a thin film through self-assembly. The wettability of treated fabrics was characterized by water contact angle, spray test and hydrostatic pressure test. The results showed that the cotton fabrics treated with 1.5% Al sol and 20 mmol/L sodium stearate showed excellent hydrophobic properties and UV protection efficiency, water contact angle could reach 146.27° and the UPF value was 164.06 (UPF rating 50+). The morphology and surface roughness were characterized by SEM and AFM. The interaction between sodium stearate and Al coating was elucidated by XPS.

  5. Viscosity Depressants for Coal Liquefaction

    NASA Technical Reports Server (NTRS)

    Kalfayan, S. H.

    1983-01-01

    Proposed process modification incorporates viscosity depressants to prevent coal from solidifying during liquefaction. Depressants reduce amount of heat needed to liquefy coal. Possible depressants are metallic soaps, such as stearate, and amides, such as stearamide and dimer acid amides.

  6. Versatile Boron Carbide-Based Visual Obscurant Compositions for Smoke Munitions

    DTIC Science & Technology

    2015-04-17

    fuel, KNO3 as a pyrotechnic oxidizer , and KCl as a combustion temperature moderator. Small amounts of calcium stearate and polymeric binders may be added...Similarly, pyrotechnic compositions based on hexachloroethane, a known toxin and suspected carcinogen,5 produce a thick hygroscopic zinc chloride aerosol...B4C) as a pyrotechnic fuel, KNO3 as a pyrotechnic oxidizer , and KCl as a combustion temperature moderator. Small amounts of calcium stearate and

  7. Tablet mechanics depend on nano and micro scale adhesion, lubrication and structure.

    PubMed

    Badal Tejedor, Maria; Nordgren, Niklas; Schuleit, Michael; Rutland, Mark W; Millqvist-Fureby, Anna

    2015-01-01

    Tablets are the most convenient form for drug administration. However, despite the ease of manufacturing problems such as powder adhesion occur during the production process. This study presents surface and structural characterization of tablets formulated with commonly used excipients (microcrystalline cellulose (MCC), lactose, mannitol, magnesium (Mg) stearate) pressed under different compaction conditions. Tablet surface analyses were performed with scanning electron microscopy (SEM), profilometry and atomic force microscopy (AFM). The mechanical properties of the tablets were evaluated with a tablet hardness test. Local adhesion detected by AFM decreased when Mg stearate was present in the formulation. Moreover, the tablet strength of plastically deformable excipients such as MCC was significantly decreased after addition of Mg stearate. Combined these facts indicate that Mg stearate affects the particle-particle bonding and thus elastic recovery. The MCC excipient also displayed the highest hardness which is characteristic for a highly cohesive material. This is discussed in the view of the relatively high adhesion found between MCC and a hydrophilic probe at the nanoscale using AFM. In contrast, the tablet strength of brittle materials like lactose and mannitol is unaffected by Mg stearate. Thus fracture occurs within the excipient particles and not at particle boundaries, creating new surfaces not previously exposed to Mg stearate. Such uncoated surfaces may well promote adhesive interactions with tools during manufacture. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Development of a UPLC-TQ/MS Approach for the Determination of Eleven Bioactive Components in Haizao Yuhu Decoction Plus-Minus Haizao and Gancao Drug Combination after Oral Administration in a Rat Model of Hypothyroidism.

    PubMed

    Ma, Yingchang; Zhang, Yang; Zhai, Yuanjuan; Zhu, Zhenhua; Pan, Ying; Qian, Dawei; Su, Shulan; Fan, Xinsheng; Duan, Jinao

    2016-12-22

    Haizao Yuhu Decoction (HYD) has been used for approximately 500 years and is well-known in Traditional Chinese Medicine for its efficacy in the treatment of thyroid-related diseases. In this study, a rapid liquid chromatography-tandem mass spectrometry method was developed for the determination of liquiritin, naringin, hesperidin, peimine, liquiritigenin, glycyrrhizic acid, bergapten, nobiletin, osthole, and glycyrrhetinic acid in rat plasma to investigate the pharmacokinetic profile of different HYD prescriptions in a rat model of hypothyroidism. The differences in pharmacokinetic parameters among the groups were compared by Student's t-test. The pharmacokinetic profile of liquiritin, naringin, hesperidin, peimine, liquiritigenin, glycyrrhizic acid, bergapten, nobiletin, osthole, and glycyrrhetinic acid showed significant differences between Haizao and Gancao anti-drug combination and other herbs in HYD. These results may contribute to the rational clinical use of HYD and reveal the compatibility profile of the Haizao and Gancao anti-drug combination.

  9. Antimutagenic components in Glycyrrhiza against N-methyl-N-nitrosourea in the Ames assay.

    PubMed

    Inami, Keiko; Mine, Yusuke; Kojo, Yukiko; Tanaka, Satomi; Ishikawa, Satoko; Mochizuki, Masataka

    2017-03-01

    Antimutagenesis against N-nitroso compounds contribute to prevention of human cancer. We have found that Glycyrrhiza aspera ethanolic extract exhibits antimutagenic activity against N-methyl-N-nitrosourea (MNU) using the Ames assay with Salmonella typhimurium TA1535. In the present study, eight purified components from Glycyrrhiza, namely glabridin, glycyrrhetinic acid, glycyrrhizin, licochalcone A, licoricesaponin H2, licoricesaponin G2, liquiritigenin and liquiritin were evaluated for their antimutagenicity against MNU in the Ames assay with S. typhimurium TA1535. Glycyrrhetinic acid, glycyrrhizin, licoricesaponin G2, licoricesaponin H2 and liquiritin did not show the antimutagenicity against MNU in S. typhimurium TA1535. Glabridin, licochalcone A and liquiritigenin reduced revertant colonies derived from MNU in S. typhimurium TA1535 without showing cytotoxic effects, indicating that these compounds possess antimutagenic activity against MNU. The inhibitory activity of glabridin and licochalcone A was more effective than that of liquiritigenin. Thus, Glycyrrhiza contains antimutagenic components against DNA alkylating, direct-acting carcinogens.

  10. Poly(ethylene glycol) hydroxystearate-based nanosized emulsions: effect of surfactant concentration on their formation and ability to solubilize quercetin.

    PubMed

    Dora, Cristiana L; Silva, Luis F C; Putaux, Jean-Luc; Nishiyama, Yoshiharu; Pignot-Paintrand, Isabelle; Borsali, Redouane; Lemos-Senna, Elenara

    2012-04-01

    Quercetin is a natural compound that has shown several biological activities. However, it displays poor water solubility and, therefore, low bioavailability. In this study, oil-in-water nanosized emulsions were obtained by the hot solvent diffusion method, using castor oil as oily phase and poly(ethylene glycol) (660)-12-hydroxystearate (PEG 660-stearate) and lecithin as surfactants. The effect of the PEG 660-stearate concentration on the droplet size of the nanosized emulsions and on the ability of these systems to load quercetin was investigated. Dynamic light scattering (DLS), transmission electron microscopy (TEM), cryo-TEM, and small-angle X-ray scattering (SAXS) were used to characterize the systems. We have demonstrated that a critical concentration of PEG 660-stearate (2.5 wt%) was needed to obtain colloidal dispersions displaying microemulsion characteristics. This colloidal dispersion, that was not optically birefringent, was constituted by a monodisperse population of 20 nm-large droplets, and exhibited excellent stability. Besides, this system was able to solubilize five times more quercetin than nanoemulsions prepared using 0.25 wt% PEG 660-stearate. SAXS results suggest that the spherical droplets have a core-shell structure. With regard to the hot solvent diffusion method, both diffusion of the solvent towards the aqueous phase and increase of the temperature above the phase inversion temperature (PIT) of PEG 660-stearate appeared to be required for obtaining clear and isotropic colloidal dispersions.

  11. Effect of different dispersing agents on the characteristics of Eudragit microspheres prepared by a solvent evaporation method.

    PubMed

    Horoz, B B; Kiliçarslan, M; Yüksel, N; Baykara, T

    2004-03-01

    Eudragit RS microspheres containing verapamil HCl for oral use were prepared using three different dispersing agents: aluminium tristearate, magnesium stearate and sucrose stearate, by a solvent evaporation method. The effects of the type and concentration of the dispersing agents and the inner phase polymer concentration on the size and T63.2%, (the time at which 63.2% of the drug is released) of microspheres were determined by multiple linear regression analysis. The morphology of microspheres was characterized by scanning electron microscopy. The surface of microspheres prepared with sucrose stearate was smoother and non-porous and the drug release from these microspheres was the fastest. When aluminium tristearate or magnesium stearate were used as dispersing agents, the particle size of microspheres became smaller. Increasing amounts of these two dispersing agents led to the accumulation of their free particles onto the surfaces of the microspheres. The drug release from the microspheres was slower than that of the microspheres from sucrose stearate depending on their hydrophobic structures. According to the results of the multiple linear regression analysis among the dispersing agents used, aluminium tristearate showed the best correlation between the examined input (dispersing agent and polymer concentrations) and output (T63.2%. and particle size) variables.

  12. Ribozymes targeted to stearoyl-ACP delta9 desaturase mRNA produce heritable increases of stearic acid in transgenic maize leaves.

    PubMed Central

    Merlo, A O; Cowen, N; Delate, T; Edington, B; Folkerts, O; Hopkins, N; Lemeiux, C; Skokut, T; Smith, K; Woosley, A; Yang, Y; Young, S; Zwick, M

    1998-01-01

    Ribozymes are RNAs that can be designed to catalyze the specific cleavage or ligation of target RNAs. We have explored the possibility of using ribozymes in maize to downregulate the expression of the stearoyl-acyl carrier protein (Delta9) desaturase gene. Based on site accessibility and catalytic activity, several ribozyme constructs were designed and transformed into regenerable maize lines. One of these constructs, a multimer hammerhead ribozyme linked to a selectable marker gene, was shown to increase leaf stearate in two of 13 maize lines. There were concomitant decreases in Delta9 desaturase mRNA and protein. The plants with the altered stearate phenotype were shown to express ribozyme RNA. The ribozyme-mediated trait was heritable, as evidenced by stearate increases in the leaves of the R1 plants derived from a high-stearate line. The increase in stearate correlated with the presence of the ribozyme gene. A catalytically inactive version of this ribozyme did not produce any significant effect in transgenic maize. This is evidence that ribozymes can be used to modulate the expression of endogenous genes in maize. PMID:9761789

  13. The effect of dust-suppressant additives on the physical properties of an irreversible hydrocolloid.

    PubMed

    Veres, E; Slabbert, J C; Becker, P

    1990-01-01

    The effects of dust-suppressant additives on certain physical properties of an irreversible hydrocolloid were studied in five test specimens formulated as follows: no additives (F0); 10% Duomeen cationic surfactant in 0.5% paraffin with 0.05% zinc stearate (F1); 10% Duomeen in 0.5% paraffin with 0.10% zinc stearate (F2); 20% Duomeen in 0.5% paraffin with 0.05% zinc stearate (F3); and 20% Duomeen in 0.5% paraffin with 0.10% zinc stearate (F4). The properties tested according to ADA specifications were mixing time, setting time, compressive strength, strain in compression, and permanent deformation under fixed strain. For each property, the variances between formulations were not significantly different (Levene p less than 0.05) whereas means were significantly different for stress (ANOVA p + 0.0001; Kruskal-Wallis p = 0.0019); strain (ANOVA p = 0.0003; Kruskal-Wallis p = 0.0228); deformation (ANOVA p = 0.0166; Kruskal-Wallis p = 0.0308). For the properties stress, strain, and permanent deformation under fixed strain, the paired differences of dust suppressants were established by using Duncan's multiple range test. Duomeen, instead of zinc stearate seems to be responsible for these effects.

  14. [Liquorice-induced hypertension and hypokalaemia].

    PubMed

    Nielsen, Mette Lundgren; Pareek, Manan; Andersen, Inger

    2012-04-09

    Consumption of large amounts of liquorice can cause hypertension and hypokalaemia. Liquorice contains glycyrrhetinic acid, which inhibits the enzyme 11 beta-hydroxysteroid dehydrogenase type 2, and ultimately leads to an apparent mineralocorticoid excess syndrome. This case report describes a 50 year-old woman presenting with hypertension and hypokalaemia-induced limb paresis due to chronic liquorice ingestion. The patient was treated with potassium supplementation and spironolactone. Her blood pressure and electrolyte status normalised within a month after cessation of liquorice intake.

  15. Connexin 43 expression on peripheral blood eosinophils: role of gap junctions in transendothelial migration.

    PubMed

    Vliagoftis, Harissios; Ebeling, Cory; Ilarraza, Ramses; Mahmudi-Azer, Salahaddin; Abel, Melanie; Adamko, Darryl; Befus, A Dean; Moqbel, Redwan

    2014-01-01

    Eosinophils circulate in the blood and are recruited in tissues during allergic inflammation. Gap junctions mediate direct communication between adjacent cells and may represent a new way of communication between immune cells distinct from communication through cytokines and chemokines. We characterized the expression of connexin (Cx)43 by eosinophils isolated from atopic individuals using RT-PCR, Western blotting, and confocal microscopy and studied the biological functions of gap junctions on eosinophils. The formation of functional gap junctions was evaluated measuring dye transfer using flow cytometry. The role of gap junctions on eosinophil transendothelial migration was studied using the inhibitor 18-a-glycyrrhetinic acid. Peripheral blood eosinophils express Cx43 mRNA and protein. Cx43 is localized not only in the cytoplasm but also on the plasma membrane. The membrane impermeable dye BCECF transferred from eosinophils to epithelial or endothelial cells following coculture in a dose and time dependent fashion. The gap junction inhibitors 18-a-glycyrrhetinic acid and octanol did not have a significant effect on dye transfer but reduced dye exit from eosinophils. The gap junction inhibitor 18-a-glycyrrhetinic acid inhibited eosinophil transendothelial migration in a dose dependent manner. Thus, eosinophils from atopic individuals express Cx43 constitutively and Cx43 may play an important role in eosinophil transendothelial migration and function in sites of inflammation.

  16. Galenic approaches in troubleshooting of glibenclamide tablet adhesion in compression machine punches

    PubMed Central

    Boniatti, Janine; Pereira Cerqueira, Ana Lúcia; de Souza, Alexandre Carnevale; Drago Hoffmeister, Cristiane Rodrigues; da Costa, Maira Assis; Prado, Livia Deris; Tasso, Leandro; Antunes Rocha, Helvécio Vinícius

    2013-01-01

    This study aimed to examine the adhesion of glibenclamide 5 mg tablets to the tools of compression machines. This problem is not commonly reported in the literature, since it is considered as tacit knowledge. The starting point was the implementation of three technical alternatives: changing the parameters of compression, evaluating the humidity of the powder blend and the manufacturer of the lubricant magnesium stearate. The adhesion was directly related to the characteristics of magnesium stearate from different manufacturers, and the feasibility of evaluating powder flow characteristics by different techniques that are not routinely followed in various pharmaceutical companies. In vitro dissolution tests showed that the magnesium stearate manufacturer can influence on the dissolution profile of glibenclamide tablets. This study presented various aspects of tablet adhesion to compression machine punches. Troubleshooting approaches can be, most of times, conducted based on previous experience, or an experimental research needs to be implemented in order to have confident results. PMID:25473333

  17. Green fabrication of coloured superhydrophobic paper from native cotton cellulose.

    PubMed

    Wen, Qiuying; Guo, Fei; Yang, Fuchao; Guo, Zhiguang

    2017-07-01

    Paper is kind of essential materials in our daily life. However, it can be easily destroyed by water owing to its superhydrophilic surface. Here, we reported a simple and green fabrication of coloured superhydrophobic paper via swelling and approximate dissolution of cotton followed by precipitation of cellulose and doping coloured stearates. The obtained paper exhibited uniform colour and superhydrophobicity, of which the colour was consistent with the doped stearates owing to the adhesion of stearate powders to the tiny floc fiber surface and we proved that the superhydrophobicity could not be damaged after abrasion resulting from the inner and outer superhydrophobicity and the increased surface roughness. This coloured superhydrophobic paper would be avoided from moisture damage and may be useful in different fields.

  18. One-step spray-coating process for the fabrication of colorful superhydrophobic coatings with excellent corrosion resistance.

    PubMed

    Li, Jian; Wu, Runni; Jing, Zhijiao; Yan, Long; Zha, Fei; Lei, Ziqiang

    2015-10-06

    A simple method was used to generate colorful hydrophobic stearate particles via chemical reactions between inorganic salts and sodium stearate. Colored self-cleaning superhydrophobic coatings were prepared through a facile one-step spray-coating process by spraying the stearate particle suspensions onto stainless steel substrates. Furthermore, the colorful superhydrophobic coating maintains excellent chemical stability under both harsh acidic and alkaline circumstances. After being immersed in a 3.5 wt % NaCl aqueous solution for 1 month, the as-prepared coatings remained superhydrophobic; however, they lost their self-cleaning property with a sliding angle of about 46 ± 3°. The corrosion behavior of the superhydrophobic coatings on the Al substrate was characterized by the polarization curve and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion test results indicated that the superhydrophobic coatings possessed excellent corrosion resistance, which could supply efficient and long-term preservation for the bare Al substrate.

  19. Molecular species of acylglycerols incorporating radiolabeled fatty acids from castor (Ricinus communis L.) microsomal incubations.

    PubMed

    Lin, Jiann-Tsyh; Chen, Jennifer M; Liao, Lucy P; McKeon, Thomas A

    2002-08-28

    Sixty-one molecular species of triacylglycerols (TAG) and diacylglycerols produced from castor microsomal incubations incorporating six different (14)C-labeled fatty acids have been identified and quantified. The preference for incorporation into TAG was in the order ricinoleate > oleate > linoleate > linolenate > stearate > palmitate. Ricinoleate was the major fatty acid incorporated, whereas stearate, linolenate, and palmitate were incorporated at low levels. Twenty-one molecular species of acylglycerols (HPLC peaks) in castor oil have also been assigned. The levels of TAG in castor oil are RRR (triricinolein) > RR-TAG > R-TAG > no R-TAG. The levels of the molecular species within the groups of RR-TAG, RL-TAG, and LL-TAG individually are ricinoleate > linoleate > oleate > linolenate, stearate, and palmitate. The results of the labeled fatty acid incorporation are consistent with ricinoleate being preferentially driven into TAG and oleate being converted to ricinoleate in castor oil biosynthesis.

  20. Effect of Lubrication on the Improvement of Uniformity in Uniaxial Powder Compaction

    NASA Astrophysics Data System (ADS)

    Taniguchi, Yukinori; Dohda, Kuniaki; Wang, Zhrgang

    Density distribution in powder compact caused by frictional force at die wall has been estimated. The pressure transmission ratio λ was defined for the estimation of the magnitude of frictional force occurrence on die wall. The density gradient α was also defined for the estimation of density distribution. The iron and pre-alloyed stainless steel powder were tested, and the performance of zinc stearate and paraffin wax applied as internal lubricant or die wall lubricant has been investigated in various conditions. The die wall lubrication becomes effective way to increase λ in comparison with the internal lubrication. Admixed lubricant prevents the occurrence of density distribution and uniform green compact is obtained in the critical amount of lubricant. Paraffin wax shows higher performance as a die wall lubricant compared with zinc stearate, and remarkable increase of lubrication effect is observed in the combination between zinc stearate as internal lubricant and paraffin wax as wall lubricant.

  1. Separation of geometric isomers of native lutein diesters in marigold (Tagetes erecta L.) by high-performance liquid chromatography-mass spectrometry.

    PubMed

    Tsao, Rong; Yang, Raymond; Young, J Christopher; Zhu, Honghui; Manolis, Tony

    2004-08-06

    Lutein is found in many foods; the richest and purest plant source is marigold flower (Tagetes erecta L.). In this plant, lutein is in the form of saturated fatty acid diesters. By using a binary mobile phase consisting of ethyl acetate and acetonitrile-methanol (9:1), improved separation was achieved on a C18-bonded phase. The unique absorption of lutein cis isomers at 330nm was used in combination with MS to identify the novel cis-lutein isomeric dimyristate, myristate-palmitate, dipalmitate, and palmitate-stearate diesters, as well as the rare combinations of both trans- and cis-lutein laurate-palmitate and trans- and cis-lutein myristate-stearate. The presence of the all-trans-lutein laurate-myristate, dimyristate, myristate-palmitate, palmitate-stearate, and distearate diesters, reported by others, was also confirmed.

  2. Site-specific S-Acylation of Influenza Virus Hemagglutinin

    PubMed Central

    Brett, Katharina; Kordyukova, Larisa V.; Serebryakova, Marina V.; Mintaev, Ramil R.; Alexeevski, Andrei V.; Veit, Michael

    2014-01-01

    S-Acylation of hemagglutinin (HA), the main glycoprotein of influenza viruses, is an essential modification required for virus replication. Using mass spectrometry, we have previously demonstrated specific attachment of acyl chains to individual acylation sites. Whereas the two cysteines in the cytoplasmic tail of HA contain only palmitate, stearate is exclusively attached to a cysteine positioned at the end of the transmembrane region (TMR). Here we analyzed recombinant viruses containing HA with exchange of conserved amino acids adjacent to acylation sites or with a TMR cysteine shifted to a cytoplasmic location to identify the molecular signal that determines preferential attachment of stearate. We first developed a new protocol for sample preparation that requires less material and might thus also be suitable to analyze cellular proteins. We observed cell type-specific differences in the fatty acid pattern of HA: more stearate was attached if human viruses were grown in mammalian compared with avian cells. No underacylated peptides were detected in the mass spectra, and even mutations that prevented generation of infectious virus particles did not abolish acylation of expressed HA as demonstrated by metabolic labeling experiments with [3H]palmitate. Exchange of conserved amino acids in the vicinity of an acylation site had a moderate effect on the stearate content. In contrast, shifting the TMR cysteine to a cytoplasmic location virtually eliminated attachment of stearate. Thus, the location of an acylation site relative to the transmembrane span is the main signal for stearate attachment, but the sequence context and the cell type modulate the fatty acid pattern. PMID:25349209

  3. The effect of excipients on the stability and phase transition rate of xylazine hydrochloride and zopiclone.

    PubMed

    Krūkle-Bērziņa, Kristīne; Actiņš, Andris

    2015-03-25

    The compatibility of thermodynamically unstable polymorph of two active pharmaceutical compounds (xylazine hydrochloride form X and zopiclone form C) with different excipients was investigated. The effects of the excipient and its amount in the sample on the thermal properties and possible chemical interactions were studied. The most commonly used excipients in the pharmaceutical industry - calcium carbonate, lactose hydrate, cellulose, magnesium stearate hydrate and calcium stearate hydrate were selected for this study. The dependence of the phase transition rate from an unstable to a more stable polymorph on the excipients and their amounts in the initial sample was analysed at 80°C, and the corresponding phase transition rate constants were calculated.

  4. Comedogenicity in rabbit: some cosmetic ingredients/vehicles.

    PubMed

    Nguyen, Shawn H; Dang, Thao P; Maibach, Howard I

    2007-01-01

    The rabbit external ear canal was used to define which chemicals caused comedone formation on topical application. Some of the tested ingredients are currently used in topically applied formulations. Certain raw materials have been shown to produce follicular hyperkeratosis in the rabbit ear assay. This study quantifies comedogenic potential of cosmetic materials, including: isopropyl palmitate, isopropyl myristate, butyl stearate, isopropyl isostearate, decyl oleate, isostearyl neopentanoate, isocetyl stearate, myristle myristate, cocoa butter, cetyl alcohol, paraffin, stearyl alcohol sodium lauryl sulfate (SLS), and petrolatum. The first nine were deemed positive. Factors aiding clinical relevance are listed.

  5. Determination of Nonpropagation Distances for 25-mm XM792 HEI-T cartridges

    DTIC Science & Technology

    1983-02-01

    mix; Item % by weight 97/3 RDX/ wax 64 Aluminum powder 35 Graphite and/or calcium stearate 1 Tracer composition: Pellet types (% by weight) Item...Magnesium (16 granulation) Magnesium (five-micron size) PTFE VITON-A Strontium nitrate Graphite Carbon black. Ethyl cellulose Weight: grams...CM i-J 3 H •H G © 19 HEI EXPLOSIVE MIX 97/3 RDX/ WAX ALUMINUM POWDER- GRAPHITE AND/OR— CALCIUM STEARATE 3 EACH, 3.350 GRAM TYPE I PELLETS

  6. 21 CFR 176.200 - Defoaming agents used in coatings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... glycol (400) esters of coconut oil fatty acids Polyethylene glycol (400) monooleate Polyethylene glycol... alcohol tert-Butyl alcohol Butyl stearate Castor oil, sulfated, ammonium, potassium, or sodium salt Cetyl... of total coating solids. Animal and vegetable fats and oils. Tall oil. Dimethylpolysiloxane...

  7. Effects of Coating Materials and Processing Conditions on Flow Enhancement of Cohesive Acetaminophen Powders by High-Shear Processing With Pharmaceutical Lubricants.

    PubMed

    Wei, Guoguang; Mangal, Sharad; Denman, John; Gengenbach, Thomas; Lee Bonar, Kevin; Khan, Rubayat I; Qu, Li; Li, Tonglei; Zhou, Qi Tony

    2017-10-01

    This study has investigated the surface coating efficiency and powder flow improvement of a model cohesive acetaminophen powder by high-shear processing with pharmaceutical lubricants through 2 common equipment, conical comil and high-shear mixer. Effects of coating materials and processing parameters on powder flow and surface coating coverage were evaluated. Both Carr's index and shear cell data indicated that processing with the lubricants using comil or high-shear mixer substantially improved the flow of the cohesive acetaminophen powder. Flow improvement was most pronounced for those processed with 1% wt/wt magnesium stearate, from "cohesive" for the V-blended sample to "easy flowing" for the optimally coated sample. Qualitative and quantitative characterizations demonstrated a greater degree of surface coverage for high-shear mixing compared with comilling; nevertheless, flow properties of the samples at the corresponding optimized conditions were comparable between 2 techniques. Scanning electron microscopy images demonstrated different coating mechanisms with magnesium stearate or l-leucine (magnesium stearate forms a coating layer and leucine coating increases surface roughness). Furthermore, surface coating with hydrophobic magnesium stearate did not retard the dissolution kinetics of acetaminophen. Future studies are warranted to evaluate tableting behavior of such dry-coated pharmaceutical powders. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  8. 21 CFR 172.615 - Chewing gum base.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...,000-21,000. Polyisobutylene Minimum molecular weight 37,000 (Flory). Polyvinyl acetate Molecular... with § 172.890. Stearic acid Complying with § 172.860. Sodium and potassium stearates Complying with... used alone or in any combination. Butylated hydroxytoluene Do. Propyl gallate Do. Miscellaneous Sodium...

  9. 21 CFR 172.615 - Chewing gum base.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (Flory). Polyvinyl acetate Molecular weight, minimum 2,000. Plasticizing Materials (Softeners) Glycerol.... Sodium and potassium stearates Complying with § 172.863. Terpene Resins Synthetic resin Consisting of... Do. Propyl gallate Do. Miscellaneous Sodium sulfate Sodium sulfide Reaction-control agent in...

  10. 21 CFR 176.200 - Defoaming agents used in coatings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... alcohol tert-Butyl alcohol Butyl stearate Castor oil, sulfated, ammonium, potassium, or sodium salt Cetyl...-(Dinonylphenyl)-ω-hydroxy-poly(oxy-1,2-ethanediyl), containing 7 to 24 moles of ethylene oxide per mole of.... Ammonium. Calcium. Magnesium. Potassium. Sodium. Zinc. Formaldehyde For use as preservative of defoamer...

  11. Separation and determination of polyethylene glycol fatty acid esters in cosmetics by a reversed-phase HPLC/ELSD.

    PubMed

    Lee, Yong Hwa; Jeong, Eun Sook; Cho, Hwang Eui; Moon, Dong-Cheul

    2008-02-15

    A comprehensive analytical method was established for the separation of polyethylene glycol (PEG) stearates according to the distribution of ethylene oxide (EO) and subsequent determination of the surfactants in cosmetic samples by using a high-performance liquid chromatography-evaporative light scattering detection. Separation of the PEG stearates comprising approximately up to 82 EO adducts was performed on a reversed-phase YMC-Pack C(8) column using water-acetonitrile gradient elution. The PEG oligomers were separated in order of the increasing number of EO adducts. Quantitation of the PEG fatty acid esters, which was separated as single peak per each component, was performed by chromatography on a reversed-phase Wakosil 10 C(18) column using water-methanol gradient elution. The standard curve to quantify the PEG stearates was constructed by the log-log plot, which showed good linearity with the correlation coefficients (R(2)) 0.998 and more. Working range, repeatability, limit of detection and recovery were acceptable for analysis of the surfactants in cosmetic products. The analytical methods were applied to characterize the PEG stearates according to the EO distributions, then to quantify the surfactants in cosmetic products.

  12. Oleochemical synthesis of an acid cleavable hydrophobe for surfactant use

    USDA-ARS?s Scientific Manuscript database

    The synthesis of a series of branched hydroxy stearates from commercially available methyl oleate and common organic acids is reported. A variety of different acids, with 3 to 8 carbon atoms, and also varying in their branching and functionality, were used. The kinetics of the ring opening reactio...

  13. 21 CFR 178.3910 - Surface lubricants used in the manufacture of metallic articles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....864 of this chapter) that have even numbers of carbon atoms in the range C8-C18 alpha-Alkyl-omega... carbon atoms in the range C4C18 and that are prepared from ethylene, aluminum, and hydrogen such that the... carbon atoms (C10 or greater) Isobutyl stearate Lanolin Linoleic acid amide Mineral oil Conforming to...

  14. 21 CFR 176.200 - Defoaming agents used in coatings.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (min. mol. wt. 3,700) Polyoxyethylated (min. 3 mols) cetyl alcohol Polyoxyethylated (min. 5 mols) oleyl alcohol Polyoxyethylated (min. 1.5 mols) tridecyl alcohol Polyoxyethylene (min. 15 mols) ester of rosin Polyoxyethylene (min. 8 mols) monooleate Polyoxyethylene (40) stearate Polyoxypropylated (min. 20 mols) butyl...

  15. Identification and Development of a Gelled Fuel through the Use of Liquid Gelling Agents

    DTIC Science & Technology

    2008-02-01

    polyacrylic acid polymer (solid) that can be used to transform many liquid products into a gel. It is suggested for use as an all-purpose thickener and...Benzene and polystyrene • Aluminum soaps (e.g., aluminum stearate) • Alcohols plus laundry detergent (aluminum soaps) Although all systems above

  16. The effect of lubricants on powder flowability for pharmaceutical application.

    PubMed

    Morin, Garett; Briens, Lauren

    2013-09-01

    Pharmaceutical tablets are manufactured through a series of batch steps finishing with compression into a form using a tablet press. Lubricants are added to the powder mixture prior to the tabletting step to ensure that the tablet is ejected properly from the press. The addition of lubricants also affects tablet properties and can affect the behavior of the powder mixture. The objective of this research was to investigate the effect of lubricants on powder flowability as flowability into the tablet press is critical. Four lubricants (magnesium stearate, magnesium silicate, stearic acid, and calcium stearate) were mixed, in varying amounts, with spray-dried lactose. In addition, magnesium stearate was also mixed with placebo granules from a high-shear granulator. Measurements based on avalanche behavior indicated flowability potential and dynamic density and were more sensitive to changes in the mixture and provided a more accurate and reproducible indication of flowability than traditional static measurements. Of the tested lubricants, magnesium stearate provided the best increase in flowability even in the low amounts commonly added in formulations.

  17. Introduction to Studies in Granular Mixing

    ERIC Educational Resources Information Center

    Llusa, Marcos; Muzzio, Fernando

    2008-01-01

    This article describes a hands-on educational activity designed to introduce students (or industrial employees) in the pharmaceutical arena to some of the most common problems in the mixing of solids: Active Pharmaceutical Ingredient (API) and lubricant (i.e. magnesium stearate) homogenization, characterization of segregation tendencies, and…

  18. Spontaneous tooth exfoliation, maxillary osteomyelitis and facial scarring following trigeminal herpes zoster infection.

    PubMed

    Pillai, Kamala G; Nayar, Kavitha; Rawal, Yeshwant B

    2006-07-01

    A case of trigeminal herpes zoster (HZ) infection affecting the left maxillary and ophthalmic divisions of the fifth cranial nerve in an immuno-competent patient is presented. Extremely rare complications such as osteonecrosis, spontaneous tooth exfoliation, secondary osteomyelitis and facial scarring were observed. Sequestrectomy, aciclovir and erythromycin stearate were effectively used in managing the case.

  19. Sensitivity of Spores to Hydrostatic Pressure Mechanisms of Inactivation, Injury and Repair Phase II

    DTIC Science & Technology

    2003-03-01

    Bacillus sp., Clostridium sporogenes, and Alicyclobacillus sp. The combined treatments of sucrose laurate, HPP and mild heat were evaluated on spores of...Bacillus and Alicyclobacillus in foods. The minimum inhibitory concentrations (MICs) of the sucrose esters were higher for Bacillus, Clostridium, and... Alicyclobacillus spp. than of Lauricidin. Sucrose stearates and sucrose palmitate were less effective and less soluble than sucrose laurates. A

  20. A new experimental design method to optimize formulations focusing on a lubricant for hydrophilic matrix tablets.

    PubMed

    Choi, Du Hyung; Shin, Sangmun; Khoa Viet Truong, Nguyen; Jeong, Seong Hoon

    2012-09-01

    A robust experimental design method was developed with the well-established response surface methodology and time series modeling to facilitate the formulation development process with magnesium stearate incorporated into hydrophilic matrix tablets. Two directional analyses and a time-oriented model were utilized to optimize the experimental responses. Evaluations of tablet gelation and drug release were conducted with two factors x₁ and x₂: one was a formulation factor (the amount of magnesium stearate) and the other was a processing factor (mixing time), respectively. Moreover, different batch sizes (100 and 500 tablet batches) were also evaluated to investigate an effect of batch size. The selected input control factors were arranged in a mixture simplex lattice design with 13 experimental runs. The obtained optimal settings of magnesium stearate for gelation were 0.46 g, 2.76 min (mixing time) for a 100 tablet batch and 1.54 g, 6.51 min for a 500 tablet batch. The optimal settings for drug release were 0.33 g, 7.99 min for a 100 tablet batch and 1.54 g, 6.51 min for a 500 tablet batch. The exact ratio and mixing time of magnesium stearate could be formulated according to the resulting hydrophilic matrix tablet properties. The newly designed experimental method provided very useful information for characterizing significant factors and hence to obtain optimum formulations allowing for a systematic and reliable experimental design method.

  1. Introduction to Studies in Granular Mixing

    ERIC Educational Resources Information Center

    Llusa, Marcos; Muzzio, Fernando

    2008-01-01

    This article describes a hands-on educational activity designed to introduce students (or industrial employees) in the pharmaceutical arena to some of the most common problems in the mixing of solids: Active Pharmaceutical Ingredient (API) and lubricant (i.e. magnesium stearate) homogenization, characterization of segregation tendencies, and…

  2. Versatile Boron Carbide-Based Energetic Time Delay Compositions

    DTIC Science & Technology

    2013-01-01

    potassium perchlorate and barium chromate, chemicals that are facing increasing regulatory scrutiny. Static tests in aluminum hand-held signal delay...stearate delay.10 Unlike perchlorate, periodate is not expected to compete with iodide in the thyroid gland due to its larger ionic radius.20 PTFE is

  3. The Surface Modification and Antimicrobial Activity of Basic Magnesium Hypochlorite Nanoparticles.

    PubMed

    Xu, Lijian; Tang, Zengmin; Xu, Jianxiong; Zhang, Jide; Du, Jingjing; Li, Na

    2015-02-01

    The basic magnesium hypochlorite (BMH) nanoparticles were prepared by two micro-emulsion techniques and modified with sodium stearate. The influences of the main technical parameters such as the addition amount of sodium stearate, reaction temperature and reaction time on the Lipophilic degree (LD) of the modified BMH nanoparticles were investigated. The characteristics of the BMH nanoparticles were analysed by means of Malvern Instruments, transmission electron microscopy (TEM), water contact angle measurements, Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA). The antimicrobial activity of the modified BMH nanoparticles was investigated with the antibacterial circle test. The results showed that the average size of the BMH nanoparticles was 305 nm. The BMH nanoparticles had been successfully modified by sodium stearate and the LD of.the modified BMH nanoparticles was 8.4% when the addition amount of sodium stearate was 0.15 g, the reaction temperature was 10 °C and the reaction time was 5 h. The dispersibility and hydrophobicity of the modified BMH nanoparticles were improved and the contact angle was up to 103 °, the modified BMH nanoparticles still had excellent antimicrobial activity after modification.

  4. A versatile semi-permanent sequential bilayer/diblock polymer coating for capillary isoelectric focusing.

    PubMed

    Bahnasy, Mahmoud F; Lucy, Charles A

    2012-12-07

    A sequential surfactant bilayer/diblock copolymer coating was previously developed for the separation of proteins. The coating is formed by flushing the capillary with the cationic surfactant dioctadecyldimethylammonium bromide (DODAB) followed by the neutral polymer poly-oxyethylene (POE) stearate. Herein we show the method development and optimization for capillary isoelectric focusing (cIEF) separations based on the developed sequential coating. Electroosmotic flow can be tuned by varying the POE chain length which allows optimization of resolution and analysis time. DODAB/POE 40 stearate can be used to perform single-step cIEF, while both DODAB/POE 40 and DODAB/POE 100 stearate allow performing two-step cIEF methodologies. A set of peptide markers is used to assess the coating performance. The sequential coating has been applied successfully to cIEF separations using different capillary lengths and inner diameters. A linear pH gradient is established only in two-step CIEF methodology using 3-10 pH 2.5% (v/v) carrier ampholyte. Hemoglobin A(0) and S variants are successfully resolved on DODAB/POE 40 stearate sequentially coated capillaries. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Fatty acid esters produced by Lasiodiplodia theobromae function as growth regulators in tobacco seedlings

    SciTech Connect

    Uranga, Carla C.; Beld, Joris; Mrse, Anthony; Córdova-Guerrero, Iván; Burkart, Michael D.; Hernández-Martínez, Rufina

    2016-04-01

    The Botryosphaeriaceae are a family of trunk disease fungi that cause dieback and death of various plant hosts. This work sought to characterize fatty acid derivatives in a highly virulent member of this family, Lasiodiplodia theobromae. Nuclear magnetic resonance and gas chromatography-mass spectrometry of an isolated compound revealed (Z, Z)-9,12-ethyl octadecadienoate, (trivial name ethyl linoleate), as one of the most abundant fatty acid esters produced by L. theobromae. A variety of naturally produced esters of fatty acids were identified in Botryosphaeriaceae. In comparison, the production of fatty acid esters in the soil-borne tomato pathogen Fusarium oxysporum, and the non-phytopathogenic fungus Trichoderma asperellum was found to be limited. Ethyl linoleate, ethyl hexadecanoate (trivial name ethyl palmitate), and ethyl octadecanoate, (trivial name ethyl stearate), significantly inhibited tobacco seed germination and altered seedling leaf growth patterns and morphology at the highest concentration (0.2 mg/mL) tested, while ethyl linoleate and ethyl stearate significantly enhanced growth at low concentrations, with both still inducing growth at 98 ng/mL. This work provides new insights into the role of naturally esterified fatty acids from L. theobromae as plant growth regulators with similar activity to the well-known plant growth regulator gibberellic acid. - Highlights: • Lasiodiplodia theobromae produces a wide variety of fatty acid esters in natural substrates. • Ethyl stearate and ethyl linoleate inhibit tobacco germination at 0.2 mg/mL. • Ethyl stearate and ethyl linoleate induce tobacco germination at 98 ng/mL. • Tobacco growth increase in ethyl stearate and ethyl linoleate parallels gibberellic acid. • A role as plant growth regulators is proposed for fatty acid esters.

  6. Effects of Saturated Long-chain Fatty Acid on mRNA Expression of Genes Associated with Milk Fat and Protein Biosynthesis in Bovine Mammary Epithelial Cells.

    PubMed

    Qi, Lizhi; Yan, Sumei; Sheng, Ran; Zhao, Yanli; Guo, Xiaoyu

    2014-03-01

    This study was conducted to determine the effects of saturated long-chain fatty acids (LCFA) on cell proliferation and triacylglycerol (TAG) content, as well as mRNA expression of αs1-casein (CSN1S1) and genes associated with lipid and protein synthesis in bovine mammary epithelial cells (BMECs). Primary cells were isolated from the mammary glands of Holstein dairy cows, and were passaged twice. Then cells were cultured with different levels of palmitate or stearate (0, 200, 300, 400, 500, and 600 μM) for 48 h and fetal bovine serum in the culture solution was replaced with fatty acid-free BSA (1 g/L). The results showed that cell proliferation tended to be increased quadratically with increasing addition of stearate. Treatments with palmitate or stearate induced an increase in TAG contents at 0 to 600 μM in a concentration-dependent manner, and the addition of 600 μM was less effective in improving TAG accumulation. The expression of acetyl-coenzyme A carboxylase alpha, fatty acid synthase and fatty acid-binding protein 3 was inhibited when palmitate or stearate were added in culture medium, whereas cluster of differentiation 36 and CSN1S1 mRNA abundance was increased in a concentration-dependent manner. The mRNA expressions of peroxisome proliferator-activated receptor gamma, mammalian target of rapamycin and signal transducer and activator of transcription 5 with palmitate or stearate had no significant differences relative to the control. These results implied that certain concentrations of saturated LCFA could stimulate cell proliferation and the accumulation of TAG, whereas a reduction may occur with the addition of an overdose of saturated LCFA. Saturated LCFA could up-regulate CSN1S1 mRNA abundance, but further studies are necessary to elucidate the mechanism for regulating milk fat and protein synthesis.

  7. [Extraction technology of effervescent granules for arresting cold pain optimized by orthogonal tests].

    PubMed

    Sun, X; Zhang, Z; Ma, L; Zhang, W

    1996-03-01

    In the extraction technology of Effervescent Granules for Arresting Cold Pain (Hantongding Paoteng Chongji), the drug combinative modes, solvent pH and drug granularity were optimized by orthogonal tests, with the total alkaloid, paeoniflorin and glycyrrhetinic acid as indexes. The experimental results show that it is better to decoct together all the recipe ingredients, with water of pH2 for the first decoction, then water of pH8 for the second decoction, and to make its granularities ranging from the original herbal pieces to particles which can pass through a No. 2 sieve.

  8. Comparative analysis of antibacterial properties and chemical composition of Glycyrrhiza glabra L. from Astrakhan region (Russia) and Calabria region (Italy).

    PubMed

    Astaf'eva, O V; Sukhenko, L T

    2014-04-01

    We compared antibacterial activity of various extracts of two licorice subspecies against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis. Diethyl carbonate extracts of Glycyrrhiza glabra root from Astrakhan region (Russia) exhibited maximum activity against the test microbial strains; activity of Astrakhan licorice was superior among 50% ethanol extracts from Astrakhan (Russia) and Calabria (Italy). Antibacterial activity is directly proportional to the content of glycyrrhizin and 18β-glycyrrhetinic acid in the extracts. According to preliminary data, the content of these chemical components in Glycyrrhiza glabra root from Astrakhan region is higher than in licorice growing in Italy, which is presumably related to climate and geographic characteristics of Astrakhan region.

  9. Chromatography of crotamiton and its application to the determination of active ingredients in ointments.

    PubMed

    Izumoto, S; Machida, Y; Nishi, H; Nakamura, K; Nakai, H; Sato, T

    1997-06-01

    Crotamiton, which is a mixture of cis and trans isomers, was investigated by several separation techniques. One of the HPLC modes, in which crotamiton eluted as a single peak, was selected for the determination of five active ingredients (crotamiton, prednisolone, glycyrrhetinic acid, dibucaine and chlorhexidine hydrochloride) in an ointment. The simultaneous determination was performed using isocratic reversed-phase mode within 20 min by employing an octyl (C8) column and a mobile phase containing sodium dodecyl sulfate (SDS) and 2-propanol. The method was successfully applied to quality control and stability testing of the ointment.

  10. Inhibition of human enterovirus 71 replication by pentacyclic triterpenes and their novel synthetic derivatives.

    PubMed

    Zhao, Chun-hui; Xu, Jie; Zhang, Ying-qiu; Zhao, Long-xuan; Feng, Bin

    2014-01-01

    A large number of bioactive pentacyclic triterpenoids have been shown to have multiple biological activities. This study was conducted to evaluate the inhibitory activities of 6 newly synthesized and novel pentacyclic triterpenoids against enterovirus 71 (EV71). The parent compound, ursolic acid (UA), showed the greatest inhibitory activity against EV71, while oleanolic acid (OA), asiatic acid (AA), and synthetic derivatives of 18-β-glycyrrhetinic acid (GA) and OA also exhibited inhibitory effects, although to lesser extents. The results suggest these compounds show potential for further optimization as antiviral candidates for treatment of EV71 infections.

  11. In situ reinforced polymers using low molecular weight compounds

    NASA Astrophysics Data System (ADS)

    Yordem, Onur Sinan

    2011-12-01

    The primary objective of this research is to generate reinforcing domains in situ during the processing of polymers by using phase separation techniques. Low molecular weight compounds were mixed with polymers where the process viscosity is reduced at process temperatures and mechanical properties are improved once the material system is cooled or reacted. Thermally induced phase separation and thermotropic phase transformation of low molar mass compounds were used in isotactic polypropylene (iPP) and poly(ether ether ketone) (PEEK) resins. Reaction induced phase separation was utilized in thermosets to generate anisotropic reinforcements. A new strategy to increase fracture toughness of materials was introduced. Simultaneously, enhancement in stiffness and reduction in process viscosity were also attained. Materials with improved rheological and mechanical properties were prepared by using thermotropic phase transformations of metal soaps in polymers (calcium stearate/iPP). Morphology and thermal properties were studied using WAXS, DSC and SEM. Mechanical and rheological investigation showed significant reduction in process viscosity and substantial improvement in fracture toughness were attained. Effects of molecular architecture of metal soaps were investigated in PEEK (calcium stearate/PEEK and sodium stearate/PEEK). The selected compounds reduced the process viscosity due to the high temperature co-continuous morphology of metal soaps. Unlike the iPP system that incorporates spherical particles, interaction between PEEK and metal soaps resulted in two discrete and co-continuous phases of PEEK and the metal stearates. DMA and melt rheology exhibited that sodium stearate/PEEK composites are stiffer. Effective moduli of secondary metal stearate phase were calculated using different composite theories, which suggested bicontinuous morphology to the metal soaps in PEEK. Use of low molecular weight crystallizable solvents was investigated in reactive systems

  12. Unequivocal glycyrrhizin isomer determination and comparative in vitro bioactivities of root extracts in four Glycyrrhiza species

    PubMed Central

    Farag, Mohamed A.; Porzel, Andrea; Wessjohann, Ludger A.

    2014-01-01

    Glycyrrhiza glabra, commonly known as licorice, is a popular herbal supplement used for the treatment of chronic inflammatory conditions and as sweetener in the food industry. This species contains a myriad of phytochemicals including the major saponin glycoside glycyrrhizin (G) of Glycyrrhetinic acid (GA) aglycone. In this study, 2D-ROESY NMR technique was successfully applied for distinguishing 18α and 18β glycyrrhetinic acid (GA). ROESY spectra acquired from G. glabra, Glycyrrhiza uralensis and Glycyrrhiza inflata crude extracts revealed the presence of G in its β-form. Anti-inflammatory activity of four Glycyrrhiza species, G, glabra, G. uralensis, G. inflata, and G. echinata roots was assessed against COX-1 inhibition revealing that phenolics rather than glycyrrhizin are biologically active in this assay. G. inflata exhibits a strong cytotoxic effect against PC3 and HT29 cells lines, whereas other species are inactive. This study presents an effective NMR method for G isomer assignment in licorice extracts that does not require any preliminary chromatography or any other purification step. PMID:25685548

  13. Formulation of carbenoxolone for delivery to the skin.

    PubMed

    Hirata, Kazumasa; Helal, Fouad; Hadgraft, Jonathan; Lane, Majella E

    2013-05-20

    Carbenoxolone (CEX), a semi-synthetic derivative of glycyrrhetinic acid, has previously been used as a disodium salt for the management of dyspepsia and peptic ulcer because of its anti-inflammatory properties. Although glycyrrhetinic acid is available in pharmaceutical and personal care products for skin care, the topical use of the free acid form of CEX, has not previously been reported. In this work we investigated the percutaneous penetration of CEX. Solubility and permeability studies were conducted using a range of solvents or skin permeation enhancers (SPEs) commonly used for skin delivery. Binary combinations of dimethyl isosorbide (DMI) and Transcutol™ (TC) with isopropyl myristate (IPM) were effective in promoting skin permeation of CEX although individual solvents were not. Alternative fatty acid esters to IPM were subsequently investigated with the most promising formulation consisting of TC and propylene glycol laurate (PGL). Interestingly, propylene glycol monolaurate (PGML) did not demonstrate comparable efficacy when combined with TC. A ternary formulation consisting of TC, PGL and IPM demonstrated the best permeation enhancement of CEX compared with all other vehicles. The findings confirm (i) the feasibility of promoting CEX penetration across the skin (ii) the synergistic effect of combinations of solvents and SPEs on dermal and transdermal delivery (iii) the necessity for more fundamental studies to explain the differential effects of fatty acid esters on the skin barrier.

  14. Novel Chemical Ligands to Ebola Virus and Marburg Virus Nucleoproteins Identified by Combining Affinity Mass Spectrometry and Metabolomics Approaches

    PubMed Central

    Fu, Xu; Wang, Zhihua; Li, Lixin; Dong, Shishang; Li, Zhucui; Jiang, Zhenzuo; Wang, Yuefei; Shui, Wenqing

    2016-01-01

    The nucleoprotein (NP) of Ebola virus (EBOV) and Marburg virus (MARV) is an essential component of the viral ribonucleoprotein complex and significantly impacts replication and transcription of the viral RNA genome. Although NP is regarded as a promising antiviral druggable target, no chemical ligands have been reported to interact with EBOV NP or MARV NP. We identified two compounds from a traditional Chinese medicine Gancao (licorice root) that can bind both NPs by combining affinity mass spectrometry and metabolomics approaches. These two ligands, 18β-glycyrrhetinic acid and licochalcone A, were verified by defined compound mixture screens and further characterized with individual ligand binding assays. Accompanying biophysical analyses demonstrate that binding of 18β-glycyrrhetinic acid to EBOV NP significantly reduces protein thermal stability, induces formation of large NP oligomers, and disrupts the critical association of viral ssRNA with NP complexes whereas the compound showed no such activity on MARV NP. Our study has revealed the substantial potential of new analytical techniques in ligand discovery from natural herb resources. In addition, identification of a chemical ligand that influences the oligomeric state and RNA-binding function of EBOV NP sheds new light on antiviral drug development. PMID:27403722

  15. 11β-hydroxysteroid dehydrogenase inhibition as a new potential therapeutic target for alcohol abuse

    PubMed Central

    Sanna, P P; Kawamura, T; Chen, J; Koob, G F; Roberts, A J; Vendruscolo, L F; Repunte-Canonigo, V

    2016-01-01

    The identification of new and more effective treatments for alcohol abuse remains a priority. Alcohol intake activates glucocorticoids, which have a key role in alcohol's reinforcing properties. Glucocorticoid effects are modulated in part by the activity of 11β-hydroxysteroid dehydrogenases (11β-HSD) acting as pre-receptors. Here, we tested the effects on alcohol intake of the 11β-HSD inhibitor carbenoxolone (CBX, 18β-glycyrrhetinic acid 3β-O-hemisuccinate), which has been extensively used in the clinic for the treatment of gastritis and peptic ulcer and is active on both 11β-HSD1 and 11β-HSD2 isoforms. We observed that CBX reduces both baseline and excessive drinking in rats and mice. The CBX diastereomer 18α-glycyrrhetinic acid 3β-O-hemisuccinate (αCBX), which we found to be selective for 11β-HSD2, was also effective in reducing alcohol drinking in mice. Thus, 11β-HSD inhibitors may be a promising new class of candidate alcohol abuse medications, and existing 11β-HSD inhibitor drugs may be potentially re-purposed for alcohol abuse treatment. PMID:26978742

  16. Hepatic 11 beta-hydroxysteroid dehydrogenase 1 involvement in alterations of glucose metabolism produced by acidotic stress in rat.

    PubMed

    Altuna, M E; Mazzetti, M B; Rago, L F; San Martín de Viale, L C; Damasco, M C

    2009-12-01

    11 beta-hydroxysteroid dehydrogenase (HSDs) enzymes regulate the activity of glucocorticoids in target organs. HSD1, one of the two existing isoforms, locates mainly in CNS, liver and adipose tissue. HSD1 is involved in the pathogenesis of diseases such as obesity, insulin resistance, arterial hypertension and the Metabolic Syndrome. The stress produced by HCl overload triggers metabolic acidosis and increases liver HSD1 activity associated with increased phosphoenolpyruvate carboxykinase, a regulatory enzyme of gluconeogenesis that is activated by glucocorticoids, with increased glycaemia and glycogen breakdown. The aim of this study was to analyze whether the metabolic modifications triggered by HCl stress are due to increased liver HSD1 activity. Glycyrrhetinic acid, a potent HDS inhibitor, was administered subcutaneously (20 mg/ml) to stressed and unstressed four months old maleSprague Dawley rats to investigate changes in liver HSD1, phosphoenolpyruvate carboxykinase (PECPK) and glycogen phosphorylase activities and plasma glucose levels. It was observed that all these parameters increased in stressed animals, but that treatment with glycyrrhetinic acid significantly reduced their levels. In conclusion, our results demonstrate the involvement of HSD1 in stress induced carbohydrate disturbances and could contribute to the impact of HSD1 inhibitors on carbohydrate metabolism and its relevance in the study of Metabolic Syndrome Disorder and non insulin-dependent diabetes mellitus.

  17. Spectroscopic analysis on structure-affinity relationship in the interactions of different oleanane-type triterpenoids with bovine serum albumin.

    PubMed

    Hou, Jia; Wang, Zhenzhong; Yue, Ying; Li, Qian; Shao, Shijun

    2015-09-01

    Oleanane-type triterpenoids serve as an important group of plant secondary metabolites with a variety of biological activities and the C-3 position substitution pattern is a significant structural feature for their biological activities. Three selected oleanane-type triterpenoids (glycyrrhizin, glycyrrhetinic acid, and carbenoxolone) bearing different substituents (glucuronic acid dimer, hydroxyl, and succinyl groups) at the C-3 position were studied for their affinities to bind bovine serum albumin (BSA) by steady-state fluorescence, synchronous, three-dimensional fluorescence and ultraviolet-visible (UV-vis) absorption spectra. The binding mechanism of the triterpenoids to BSA is due to the formation of the triterpenoids-BSA complex and the binding affinity is strongest for carbenoxolone and ranked in the order carbenoxolone > glycyrrhetinic acid > glycyrrhizin. The thermodynamic parameters calculated at different temperatures showed that triterpenoids binding to BSA primarily depended on hydrophobic interaction and hydrogen bonding. The distance between the bound triterpenoid and BSA was determined on the basis of the Förster's energy transfer theory. Displacement experiments using phenylbutazone and ibuprofen showed the binding site of triterpenoids on BSA at subdomain IIA (Sudlow's site I). The effect of triterpenoids on BSA conformation was analyzed by UV-vis absorption, and synchronous and three-dimensional fluorescence spectra. These results revealed that the C-3 position substitution pattern significantly affects the structure-affinity relationships of oleanane-type triterpenoid binding to BSA and further affects the bioavailability of triterpenoids in the blood circulatory system. Copyright © 2014 John Wiley & Sons, Ltd.

  18. Analysis of bioactive components and pharmacokinetic study of herb-herb interactions in the traditional Chinese patent medicine Tongmai Yangxin Pill.

    PubMed

    Fan, Yaya; Man, Shuli; Li, Hongfa; Liu, Yuanxue; Liu, Zhen; Gao, Wenyuan

    2016-02-20

    Tongmai Yangxin (TMYX) Pill is a traditional Chinese patent medicine, composed of eleven Chinese medicinal herbs. It has been used to treat coronary heart disease for several decades. In this study, six male Sprague-Dawley rats were dosed orally with TMYX methanol extract, and a serum pharmacochemistry technique was used to screen absorbed bioactive compounds by UPLC/Q-TOF-MS. By comparing MS spectra to the published literature data, 40 bioactive components were identified. The results indicated that almost 45% of the absorbed compounds were from Radix Glycyrrhizae (GC). Subsequently, a reliable HPLC method was used to determine the concentrations of liquiritin, liquiritigenin, isoliquiritigenin, glycyrrhizic acid, and glycyrrhetinic acid in rat plasma following oral administration of GC or the combination of GC and Ramulus Cinnamomi (GZ). The results showed that GZ enhanced the absorption of four bioactive components: liquiritigenin, isoliquiritigenin, glycyrrhizic acid, and glycyrrhetinic acid. The data demonstrate that herb combination in TMYX Pill exhibit a synergistic action. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Physicochemical properties of magnesium salicylate.

    PubMed

    Alam, A S; Gregoriades, D

    1981-08-01

    Magnesium salicylate tetrahydrate is a nonhygroscopic, crystalline powder, whereas anhydrous magnesium salicylate is amorphous and very hygroscopic. Magnesium salicylate tetrahydrate tablets formulated with gelatin as a binder showed a dissolution half-life (t1/2) of 12 min, whereas a formulation using pregelatinized starch as a binder showed a t1/2 of 33 min. The optimum level of calcium stearate in the formulation was determined by the oscilloscope tracings of compressional and ejectional forces from an instrumented rotary tableting machine. Increasing the level of calcium stearate from 1 to 1.5 and 2% resulted in dissolution t1/2 values of 12, 18, and 21 min, respectively, and a higher incidence of softer tablets and capping.

  20. [Raman spectrometry of several saturated fatty acids and their salts].

    PubMed

    Luo, Man; Guan, Ping; Liu, Wen-hui; Liu, Yan

    2006-11-01

    Saturated fatty acids and their salts widely exist in the nature, and they are well known as important chemical materials. Their infrared spectra have been studied in detail. Nevertheless, few works on the Raman spectra characteristics of saturated fatty acids and their salts have been published before. Man-made crystals of acetic acid, stearic acid, calcium acetate, magnesium acetate, calcium stearate and magnesium stearate were investigated by means of Fourier transform Raman spectrometry for purpose of realizing their Raman spectra. Positive ions can cause the distinctions between the spectra of saturated fatty acids and their salts. The differences in mass and configuration between Ca2+ and Mg2+ result in the Raman spectra's diversity between calcium and magnesium salts of saturated fatty acids. Meanwhile, it is considered that the long carbon chain weakened the influence of different positive ions on the salts of saturated fatty acids.

  1. [The identification of several saturated fatty acids and their salts by means of infrared spectrometry].

    PubMed

    Luo, Man; Guan, Ping; Liu, Wen-hui

    2007-02-01

    It is considered that saturated fatty acids and their salts may be potential hydrocarbon-generation matters in carbonate rocks. However, there is no effective method to distinguish them from natural sediments, making recognizing their distribution in sediments a challenge. Formic acid, acetic acid, stearic acid, calcium formate, calcium acetate, magnesium acetate, calcium stearate, and magnesium stearate from some chemical plants were investigated by means of Fourier transform infrared spectroscopy. Their infrared spectra were obtained and the distinctions of the infrared spectra between saturated fatty acids and their salts were studied in detail. The differences in the group's electron-releasing ability, molecular reduced mass, ion configuration and the length of carbon chain can cause wavelength shifts of infrared absorption peaks of the saturated fatty acids and their salts. The research provides a method for the identification of saturated fatty acids and their salts in samples from nature.

  2. A study of micronized poloxamers as lubricants in direct compression of tablets.

    PubMed

    Muzíková, Jitka; Vyhlídalová, Barbora; Pekárek, Tomás

    2013-01-01

    The study evaluates the micronized poloxamers Lptrol micro127 (poloxamer 407) and Lptrol micro 68 (poloxamer 188) as lubricants in combination with the dry binders microcrystalline cellulose and spray-dried lactose. Magnesium stearate was employed as the comparative lubricant. The parameters under study included energy for friction, plasticity, ejection force, tensile strength of tablets, and disintegration time of tablets. The factors of influence were the concentration of lubricants, compression force, and mixing parameters. The lubricating effect of micronized poloxamers was smaller than that of magnesium stearate. Higher concentrations of poloxamers decreased the tensile strength of tablets from microcrystalline cellulose, shortened the disintegration time, and slightly prolonged the disintegration time in the case of spray-dried lactose. Parameters of mixing of dry binders with poloxamers influenced the tested parameters of compression more in the case of spray-dried lactose. In microcrystalline cellulose, they influenced more the tensile strength and disintegration time of tablets.

  3. Compaction of AWBA fuel pellets without binders (AWBA Development Program)

    SciTech Connect

    Johnson, R.G.R.

    1982-08-01

    Highly active oxide fuel powders, composed of UO/sub 2/, UO/sub 2/-ThO/sub 2/, or ThO/sub 2/, were compacted into ultra-high density pellets without the use of binders. The objective of the study was to select the optimum die lubricant for compacting these powders into pellets in preparation for sintering to densities in excess of 97% Theoretical Density. The results showed that sintered density was a function of both the lubricant bulk density and concentration with the lowest bulk density lubricant giving the highest sintered densities with a lubricant concentration of 0.1 weight percent. Five calcium and zinc stearates were evaluated with a calcium stearate with a 15 lb/ft/sup 3/ bulk density being the best lubricant.

  4. [Stearic acid methyl ether: a new extracellular metabolite of the obligate methylotrophic bacterium Methylophilus quaylei].

    PubMed

    Terekhova, E A; Stepicheva, N A; Pshenichnikova, A B; Shvets, V I

    2010-01-01

    Methyl esters of fatty acids, free fatty acids, and hydrocarbons were found in the culture liquid and in the cellular lipids of the obligate methylotrophic bacterium Methylophilus quaylei under optimal growth conditions and osmotic stress. The main extracellular hydrophobic metabolite was methyl stearate. Exogenous free fatty acids C16-C18 and their methyl esters stimulated the M. quaylei growth and survivability, as well as production of exopolysaccharide under osmotic and oxidative stress, playing the role of growth factors and adaptogens. The order of hydrophobic supplements according to the ability to stimulate bacterial growth is C18 : 1 > C18 : 0 > C16 : 0 > methyl oleate > methyl stearate > no supplements > C14: 0 > C12 : 0. The mechanism underlying the protective action of fatty acids and their methyl esters is discussed.

  5. Interactions of Veratrum Alkaloids, Procaine, and Calcium with Monolayers of Stearic Acid and Their Implications for Pharmacological Action

    PubMed Central

    Shanes, Abraham M.; Gershfeld, Norman L.

    1960-01-01

    The interactions of veratridine, cevadine, veracevine, and veratramine with monolayers of stearic acid show marked differences. Veratridine and cevadine, at concentrations that are known from potential, ionic flux, and other measurements to affect living membranes, react strongly with the film and appear to cause an "interfacial dissolution" whereby both the alkaloid and the stearate leave the surface. Veracevine at the same concentration does not interact with the film. The veratramine reaction is weak, much like that of the local anesthetic procaine. The veratridine and cevadine effects are antagonized by 10-3 M Ca++, low pH, and 3.7 and 7.4 x 10-3 M procaine. These differences among the veratrum alkaloids and the antagonisms parallel effects observed in living systems. Such parallelism suggests that similar physical interactions are involved in the stearate film and in natural membranes. PMID:13750673

  6. Compatibility of the antitumoral beta-lapachone with different solid dosage forms excipients.

    PubMed

    Cunha-Filho, Marcílio S S; Martínez-Pacheco, Ramón; Landín, Mariana

    2007-11-30

    The objective of the present study was to evaluate the compatibility of the beta-lapachone (betaLAP), an antitumoral drug in clinical phase, with pharmaceutical excipients of common use including diluents, binders, disintegrants, lubricants and solubilising agents. Differential scanning calorimetry (DSC) was used for a first screening to find small variations in peak temperatures and/or their associated enthalpy for six drug/excipient combinations (magnesium stearate, sodium estearyl fumarate, dicalcium phosphate dihydrate, mannitol, randomized methyl-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin), which indicate some degree of interaction. Additional studies using Fourier transformed infrared spectroscopy (FTIR), optical microscopy (OM) and heating-cooling DSC (HC-DSC) confirmed the incompatibility of betaLAP with magnesium stearate and dicalcium phosphate dihydrate. Those excipients should be avoided in the development of solid dosage forms.

  7. Preservation properties of in situ modified CaCO3-chitosan composite coatings.

    PubMed

    Sun, Tong; Hao, Wen-ting; Li, Jian-rong; Dong, Zhi-jian; Wu, Chao-ling

    2015-09-15

    To improve the dispersibility, hydrophilia constraints of primitive particle size, and reduce the economic cost, in situ modified CaCO3-chitosan composite coatings were prepared by tape-casting with different modifiers. The coating structures were characterised, and the preservation properties of the coatings were evaluated by fresh indices of Sciaenops ocellatus. The results revealed that the coatings were homogeneous and compact when the in situ modifier was sodium stearate. Besides, the amide I group of chitosan disappeared and hydrogen bonds were formed between the nano-CaCO3 and the chitosan. Meanwhile, the preservation effects to S. ocellatus of the coatings modified in situ by sodium stearate and sodium citrate were better. This was because the coatings effectively prevented oxygen and bacteria from reaching S. ocellatus, and thus inhibited the degradation of the proteins and lipids. The in situ modified method is conducive to chitosan coating properties, which will be widely used in the food preservation field.

  8. Erythromycin estolate and jaundice.

    PubMed Central

    Inman, W H; Rawson, N S

    1983-01-01

    Using prescription-event monitoring to determine whether erythromycin estolate was a more frequent cause of jaundice than erythromycin stearate or tetracycline 12 208 patients, for whom 5343 doctors had prescribed one of the three drugs, were identified by the Prescription Pricing Authority. Of the questionnaires sent to general practitioners about the possible occurrence of jaundice, 76% were returned. There were 16 reports of jaundice, of which four were attributable to gall stones, three to cancer, six to viral hepatitis, and only three were possibly related to an antibiotic. All three patients, in whom the antibiotic was a possible cause, had been treated with erythromycin stearate. No case was attributable to the estolate which had previously been suspected of being a more frequent cause of jaundice. Although the incidence is unknown, it is very unlikely to be more than one in 100. PMID:6407653

  9. EPR investigation of some gamma-irradiated excipients

    NASA Astrophysics Data System (ADS)

    Aleksieva, Katerina; Yordanov, Nicola D.

    2012-09-01

    The results of electron paramagnetic resonance (EPR) studies on some excipients: lactose, microcrystalline cellulose (avicel), starch, dioxosilane (aerosil), talc and magnesium stearate before and after gamma-irradiation are reported. Before irradiation, all samples are EPR silent except talc. After gamma-irradiation, they show complex spectra except magnesium stearate, which is EPR silent. Studies show the influence of gamma-irradiation on EPR spectra and stability of gamma-induced radicals. Analysis of the EPR spectrum of gamma-irradiated talc shows that this material is radiation insensitive. Only lactose forms stable-free radicals upon gamma sterilization and can be used for identification of radiation processing for a long time period thereafter.

  10. Advanced Boron Carbide-Based Visual Obscurants for Military Smoke Grenades

    DTIC Science & Technology

    2014-07-13

    hexachloroethane and zinc oxide . This makes one AN-M8 HC grenade functionally equivalent to about three M83 TA grenades, and the performance of the former...compositions contain B4C/KNO3 as a pyrotechnic fuel/ oxidizer pair, KCl as a diluent, and calcium stearate as a burning rate modifier. Both the B4C...hygroscopic zinc chloride aerosol laced with soot and chlorinated organics, have been responsible for several injuries and deaths. 5 Hexa- chloroethane

  11. TAK-242, a small-molecule inhibitor of Toll-like receptor 4 signalling, unveils similarities and differences in lipopolysaccharide- and lipid-induced inflammation and insulin resistance in muscle cells.

    PubMed

    Hussey, Sophie E; Liang, Hanyu; Costford, Sheila R; Klip, Amira; DeFronzo, Ralph A; Sanchez-Avila, Alicia; Ely, Brian; Musi, Nicolas

    2012-11-30

    Emerging evidence suggests that TLR (Toll-like receptor) 4 and downstream pathways [MAPKs (mitogen-activated protein kinases) and NF-κB (nuclear factor κB)] play an important role in the pathogenesis of insulin resistance. LPS (lipopolysaccharide) and saturated NEFA (non-esterified fatty acids) activate TLR4, and plasma concentrations of these TLR4 ligands are elevated in obesity and Type 2 diabetes. Our goals were to define the role of TLR4 on the insulin resistance caused by LPS and saturated NEFA, and to dissect the independent contribution of LPS and NEFA to the activation of TLR4-driven pathways by employing TAK-242, a specific inhibitor of TLR4. LPS caused robust activation of the MAPK and NF-κB pathways in L6 myotubes, along with impaired insulin signalling and glucose transport. TAK-242 completely prevented the inflammatory response (MAPK and NF-κB activation) caused by LPS, and, in turn, improved LPS-induced insulin resistance. Similar to LPS, stearate strongly activated MAPKs, although stimulation of the NF-κB axis was modest. As seen with LPS, the inflammatory response caused by stearate was accompanied by impaired insulin action. TAK-242 also blunted stearate-induced inflammation; yet, the protective effect conferred by TAK-242 was partial and observed only on MAPKs. Consequently, the insulin resistance caused by stearate was only partially improved by TAK-242. In summary, TAK-242 provides complete and partial protection against LPS- and NEFA-induced inflammation and insulin resistance, respectively. Thus, LPS-induced insulin resistance depends entirely on TLR4, whereas NEFA works through TLR4-dependent and -independent mechanisms to impair insulin action.

  12. Extinguishing agent for combustible metal fires

    DOEpatents

    Riley, John F.; Stauffer, Edgar Eugene

    1976-10-12

    A low chloride extinguishing agent for combustible metal fires comprising from substantially 75 to substantially 94 weight percent of sodium carbonate as the basic fire extinguishing material, from substantially 1 to substantially 5 weight percent of a water-repellent agent such as a metal stearate, from substantially 2 to substantially 10 weight percent of a flow promoting agent such as attapulgus clay, and from substantially 3 to substantially 15 weight percent of a polyamide resin as a crusting agent.

  13. The Synthesis of Polymer Precursors and Exploratory Research Based on Acetylene Displacement Reaction

    DTIC Science & Technology

    1980-10-01

    the standard catalyst for this reaction, we did try several others including copper stearate, cupric ethylacetoacetate and cuprous bromide. In the...latter case, a trace of copper powder was added to minimize disproportionation of the cuprous ion . Cuprous chloride appeared to be the most effective...toluene with a catalytic amount of sodium hydroxide. The solution produced had a very dark red color which was removed by passage through fuller’s

  14. Biodegradable Poly (Ester Urethane) Urea Biomaterials For Applications in Combat Casualty Care

    DTIC Science & Technology

    2006-11-01

    conflict culture positive for bacteria .2 Open fractures are a common source of these infections, and represent the most challenging to treat. In...stearate, stannous octoate, glycerol, and ε-caprolactone were purchased from Aldrich (St. Louis, MO). Glycolide and DL- lactide were purchased from...comprising a poly(ε-caprolactone-co- glycolide-co- lactide ) triol.5 Foams were synthesized from a 900-Da triol. Additionally, water (the blowing agent

  15. Cinnamyl alcohols and methyl esters of fatty acids from Wedelia prostrata callus cultures.

    PubMed

    El-Mawla, Ahmed M A Abd; Farag, Salwa F; Beuerle, Till

    2011-01-01

    Two methyl esters of fatty acids, namely octadecanoic acid methyl ester (methyl stearate) and hexadecanoic acid methyl ester (methyl palmitate), in addition to four cinnamyl alcohol derivatives, sinapyl alcohol, coniferyl alcohol, p-coumaryl alcohol and coniferyl alcohol 4-O-glucoside (coniferin), were isolated from callus cultures of Wedelia prostrata. The structure of coniferin was established by spectroscopic and chemical methods, while the other compounds were identified by gas chromatography-mass spectrometry and thin layer chromatography in comparison with standards.

  16. Free Fatty Acids Modulate Thrombin Mediated Fibrin Generation Resulting in Less Stable Clots

    PubMed Central

    Tanka-Salamon, Anna; Komorowicz, Erzsébet; Szabó, László; Tenekedjiev, Kiril

    2016-01-01

    Upon platelet activation, free fatty acids are released at the stage of thrombus formation, but their effects on fibrin formation are largely unexplored. Our objective was to characterize the kinetic effects of fatty acids on thrombin activity, as well as the structural and mechanical properties of the resultant fibrin clots. Thrombin activity on fibrinogen was followed by turbidimetry and detailed kinetic characterization was performed using a fluorogenic short peptide substrate. The viscoelastic properties of fibrin were measured with rotatory oscillation rheometer, whereas its structure was analyzed with scanning electron microscopy (SEM). In turbidimetric assays of fibrin generation, oleate and stearate at physiologically relevant concentrations (60–600 μM) produced a bell-shaped inhibitory dose response, increasing 10- to 30-fold the time to half-maximal clotting. Oleate inhibited thrombin activity on a short peptide substrate according to a mixed-type inhibitor pattern (a 9-fold increase of the Michaelis constant, Km and a 20% decrease of the catalytic constant), whereas stearate resulted in only a minor (15%) drop in the catalytic constant without any change in the Km. Morphometric analysis of SEM images showed a 73% increase in the median fiber diameter in the presence of stearate and a 20% decrease in the presence of oleate. Concerning the viscoelastic parameters of the clots, storage and loss moduli, maximal viscosity and critical shear stress decreased by 32–65% in the presence of oleate or stearate, but loss tangent did not change indicating decreased rigidity, higher deformability and decreased internal resistance to shear stress. Our study provides evidence that free fatty acids (at concentrations comparable to those reported in thrombi) reduce the mechanical stability of fibrin through modulation of thrombin activity and the pattern of fibrin assembly. PMID:27942000

  17. Relative flow rates of explosive powders

    SciTech Connect

    Willson, V.P.

    1988-05-31

    A study was performed to determine the relative flow rates of various explosive powders and evaluate their adaptability for use in automated dispensing systems. Results showed that PBX 9407, LX-15, RX-26-BH, and HNAB are potential candidates for use in these systems. It was also shown that powders with graphite and stearate additives generated the least amount of static and were the easiest to handle.

  18. Au/Cr-ZnO-Ni structured metal-insulator-metal diode fabrication using Langmuir-Blodgett technique for infrared sensing

    NASA Astrophysics Data System (ADS)

    Azad, Ibrahim; Ram, Manoj K.; Goswami, D. Yogi; Stefanakos, Elias

    2016-05-01

    The thin nanolayer film of ZnO was synthesized through Langmuir-Blodgett (LB) organic precursor film. The zinc stearate monolayer was formed at air-water interface using zinc acetate as a subphase. The zinc stearate monolayers were deposited on silicon (Si), glass, and gold (Au)/chromium (Cr) plated Silicon (Si) substrates using LB technique. Later, the zinc stearate multilayers LB films on various substrates were annealed at two different temperatures (300oC and 550oC) for the fabrication of zinc oxide (ZnO) nanolayer film. The zinc stearate monolayers as well zinc oxide (ZnO) nanolayer films were characterized using atomic force microscopy (AFM) and X-ray diffraction techniques. The X-ray diffraction measurement has shown the hexagonal wurtzite structure of the ZnO nanolayer on the substrate. The average surface roughness was estimated to be 1.076 nm using AFM technique. The metal-insulator-metal (MIM) diode structure was realized by sandwiching ZnO nanolayer film between thin layer of Gold (Au)/Chromium (Cr) and Nickel (Ni) on silicon substrates. The electron tunneling conduction mechanism is understood through the current-voltage (I-V) characteristics of MIM diode. The highest measured sensitivity magnitude of 20 in inverse of voltage (V-1) with rectification ratio of nearly 10 at +/-400 mV in MIM diode is an indicative of its potential application in infrared sensing applications. However, the thin film of ZnO synthesized using LB film as an insulating layer in metal-insulator-metal diode structure was studied for the first time.

  19. Transport of heptafluorostearate across model membranes. Membrane transport of long-chain fatty acid anions I.

    PubMed

    Schmider, W; Fahr, A; Blum, H E; Kurz, G

    2000-05-01

    Heptafluorostearic acid, an isogeometric derivative of stearic acid, has a pK(a) value of about 0.5. To evaluate the suitability of heptafluorostearate as model compound for anions of long-chain fatty acids in membrane transport, monolayer and liposome studies were performed with lipid mixtures containing phospholipids;-cholesterol-heptafluorostearate or stearate (100:40:20 molar ratios). Transfer of heptafluorostearate and stearate from liposomes to bovine serum albumin (BSA) was followed by measuring the intrinsic fluorescence of BSA. The percentage of heptafluorostearate, equivalent to the amount placed in their outer monolayer, transferred from liposomes (120;-130 nm diameter) to BSA was 55.7 +/- 3.7% within 10 min at 25 degrees C and 55 +/- 2% within 5 min at 37 degrees C. Slow transfer of 22.7 +/- 2.5% of heptafluorostearate at 25 degrees C followed with a half-life of 2.3 +/- 0.4 h and of 20 +/- 4% at 37 degrees C with a half-life of 0.9 +/- 0.1 h until the final equilibrium distributions between BSA and liposomes were reached, 79 +/- 6% to 21 +/- 5% at 25 degrees C and 75 +/- 5% to 25 +/- 4% at 37 degrees C. The pseudounimolecular rate constants for flip-flop of heptafluorostearate equal k(FF,25) = 0.24 +/- 0.05 h(-) and k(FF,37) = 0.6 +/- 0.1 h(-), respectively. By comparison, transfer of stearate required only 3 min to reach equilibrium distribution. The difference between heptafluorostearate and stearate may be explained by a rapid flip-flop movement of the un-ionized fatty acids which exist in different concentrations in accordance with their pK(a) values. Half-life of flip-flop of heptafluorostearate makes it suitable to study mediated membrane transport of long-chain fatty acid anions.

  20. Effect of the aqueous extract of Psidium guajava on erythromycin-induced liver damage in rats.

    PubMed

    Sambo, N; Garba, S H; Timothy, H

    2009-12-01

    The effect of Psidium guajava extract on erythromycin-induced liver damage in albino rats was investigated using 30 normal rats grouped into six. Group I and II served as the normal and treatment controls that were administered with normal saline and 100 mg/kg body weight of erythromycin stearate daily for 14 days respectively. Rats in group III were administered 450 mg/kg body weight of Psidium guajava only for 7 days while rats in groups IV, V and VI were administered Psidium guajava extract for 7 days and 100mg/kg body weight of erythromycin for 14 days. Histopathological investigation of the liver tissues revealed striking oedema and mild periportal mononuclear cell infiltration of hepatic cords in the liver of rats administered 100 mg/kg of erythromycin stearate and 300/450 mg/kg of Psidium guajava extract. Pretreatment with 150 mg/kg of Psidium guajava extract showed a slight degree of protection against the induced hepatic injury caused by 100 mg/kg of erythromycin stearate. Biochemical analysis of the serum obtained revealed a significant increase in serum levels of hepatic enzymes measured in the groups administered with 100 mg/kg of erythromycin stearate and 300/450 mg/kg of Psidium guajava extract compared to the control groups and those pretreated with 150 mg/kg of Psidium guajava extract. This study has shown that the aqueous extract of psidium guajava leaf possesses hepatoprotective property at lower dose and a hepatotoxic property at higher dose but further studies with prolonged duration is recommended.

  1. Versatile Boron Carbide-Based Energetic Time Delay Compositions

    DTIC Science & Technology

    2013-07-16

    potassium perchlorate and barium chromate, chemicals that are facing increasing regulatory scrutiny. Static tests in aluminum hand-held signal delay...stearate delay.10 Unlike perchlorate, periodate is not expected to compete with iodide in the thyroid gland due to its larger ionic radius.20 PTFE is...contains potassium perchlorate and barium chromate, chemicals that are facing increasing regulatory scrutiny. Static tests in aluminum hand-held signal

  2. NMR metabolomics profiling of blood plasma mimics shows that medium- and long-chain fatty acids differently release metabolites from human serum albumin.

    PubMed

    Jupin, M; Michiels, P J; Girard, F C; Spraul, M; Wijmenga, S S

    2014-02-01

    Metabolite profiling by NMR of body fluids is increasingly used to successfully differentiate patients from healthy individuals. Metabolites and their concentrations are direct reporters of body biochemistry. However, in blood plasma the NMR-detected free-metabolite concentrations are also strongly affected by interactions with the abundant plasma proteins, which have as of yet not been considered much in metabolic profiling. We previously reported that many of the common NMR-detected metabolites in blood plasma bind to human serum albumin (HSA) and many are released by fatty acids present in fatted HSA. HSA is the most abundant plasma protein and main transporter of endogenous and exogenous metabolites. Here, we show by NMR how the two most common fatty acids (FAs) in blood plasma - the long-chain FA, stearate (C18:0) and medium-chain FA, myristate (C14:0) - affect metabolite-HSA interaction. Of the set of 18 common NMR-detected metabolites, many are released by stearate and/or myristate, lactate appearing the most strongly affected. Myristate, but not stearate, reduces HSA-binding of phenylalanine and pyruvate. Citrate signals were NMR invisible in the presence of HSA. Only at high myristate-HSA mole ratios 11:1, is citrate sufficiently released to be detected. Finally, we find that limited dilution of blood-plasma mimics releases HSA-bound metabolites, a finding confirmed in real blood plasma samples. Based on these findings, we provide recommendations for NMR experiments for quantitative metabolite profiling.

  3. NMR metabolomics profiling of blood plasma mimics shows that medium- and long-chain fatty acids differently release metabolites from human serum albumin

    NASA Astrophysics Data System (ADS)

    Jupin, M.; Michiels, P. J.; Girard, F. C.; Spraul, M.; Wijmenga, S. S.

    2014-02-01

    Metabolite profiling by NMR of body fluids is increasingly used to successfully differentiate patients from healthy individuals. Metabolites and their concentrations are direct reporters of body biochemistry. However, in blood plasma the NMR-detected free-metabolite concentrations are also strongly affected by interactions with the abundant plasma proteins, which have as of yet not been considered much in metabolic profiling. We previously reported that many of the common NMR-detected metabolites in blood plasma bind to human serum albumin (HSA) and many are released by fatty acids present in fatted HSA. HSA is the most abundant plasma protein and main transporter of endogenous and exogenous metabolites. Here, we show by NMR how the two most common fatty acids (FAs) in blood plasma - the long-chain FA, stearate (C18:0) and medium-chain FA, myristate (C14:0) - affect metabolite-HSA interaction. Of the set of 18 common NMR-detected metabolites, many are released by stearate and/or myristate, lactate appearing the most strongly affected. Myristate, but not stearate, reduces HSA-binding of phenylalanine and pyruvate. Citrate signals were NMR invisible in the presence of HSA. Only at high myristate-HSA mole ratios 11:1, is citrate sufficiently released to be detected. Finally, we find that limited dilution of blood-plasma mimics releases HSA-bound metabolites, a finding confirmed in real blood plasma samples. Based on these findings, we provide recommendations for NMR experiments for quantitative metabolite profiling.

  4. Novel approach to DPI carrier lactose with mechanofusion process with additives and evaluation by IGC.

    PubMed

    Kumon, Michiko; Suzuki, Masahiko; Kusai, Akira; Yonemochi, Etsuo; Terada, Katsuhide

    2006-11-01

    The effect of lactose carrier surface property on the inhalation profile of dry powder inhaler (DPI) was evaluated using a micronized drug (Compound A) by inverse gas chromatography (IGC). Mechanofusion with magnesium stearate (Mg-St) or sucrose stearate increased the fine particle fraction (FPF), considered to be due to decrease in the interaction between Compound A and the lactose carrier. The effect of Compound A concentration on FPF was smaller in mechanofusion-processed lactose compared to intact lactose, especially when processed with Mg-St. The relationship between the IGC parameters of the lactose and FPF was also investigated. FPF increased as both the dispersive component of the surface energy and acidity similarity between the lactose carriers and Compound A increased. Although further investigation is necessary, it could be suggested that acidity similarity decreases the interaction between Compound A and lactose, thus contributing to the increase in the FPF. In conclusion, (1) mechanofusion with Mg-St or sucrose stearate could be an effective method to improve FPF of a DPI drug formulation; (2) IGC would be a valuable method to investigate the interaction between a drug and the DPI carrier; and (3) a relationship between surface acidity and inhalation profile was suggested.

  5. Dyneon THV, a fluorinated thermoplastic as a novel material for microchip capillary electrophoresis.

    PubMed

    Aboud, Nacéra; Ferraro, Davide; Taverna, Myriam; Descroix, Stéphanie; Smadja, Claire; Thuy Tran, N

    2016-10-21

    In this work, we have investigated Dyneon THV, a fluorinated material, as a new material to afford electrokinetic separations in microfluidic devices. To overcome protein adsorption, two poly(ethylene oxide) (PEO)-based coatings have been investigated: Pluronic F127 and PEO stearate 40. The best results were obtained with the PEO stearate 40 coating which allowed decreasing the surface contact angle from 91 ± 3 to 76°± 3. With this surface treatment, a 66% reduction of the electroosmotic mobility at pH 8.0 and a marked suppression of protein adsorption were observed compared to a native Dyneon THV microchip. Finally, a separation of fluorescently labeled proteins (bovine serum albumin and trypsin inhibitor), well-known for their strong tendency to adsorb on hydrophobic surfaces, was successfully achieved in an HEPES buffer with a PEO stearate 40 treated microchip by capillary zone electrophoresis. Furthermore, we demonstrated the possibility to perform non-aqueous capillary electrophoresis analysis of hydrophobic dyes using various solvents in untreated microchips. The overall results demonstrated not only the suitability of the Dyneon THV microchip for electrokinetic separations, but also its versatility allowing different separation modes to be implemented with the same microchip material.

  6. Determination of tackiness of chitosan film-coated pellets exploiting minimum fluidization velocity.

    PubMed

    Fernández Cervera, M; Heinämäki, J; Räsänen, E; Antikainen, O; Nieto, O M; Iraizoz Colarte, A; Yliruusi, J

    2004-08-20

    The tackiness of aqueous chitosan film coatings and effects of anti-sticking agents on sticking tendency, were evaluated. A novel rapid method exploiting minimum fluidization velocity to determine tackiness was introduced and tested. The pressure difference over the miniaturized fluidized-bed was precisely recorded as a function of velocity of fluidization air. High molecular weight chitosan plasticized with glycerol was used as a film-forming agent. Magnesium stearate, titanium dioxide, colloidal silicon dioxide and glyceryl-1-monostearate (GMS) were studied as anti-sticking agents. Film coatings were performed in a miniaturized top-spray coater. The incorporation of anti-sticking agents led to a clear decrease in tackiness of the chitosan films, and magnesium stearate and GMS were shown the most effective. Film-coated pellets containing magnesium stearate and GMS as an anti-sticking agent were very easily fluidized (showing very low values of minimum fluidization velocity) and were thus classified as the best flowing and the least sticking samples. Both these additives were found anti-sticking agents of choice for aqueous chitosan film coatings. Determination of the experimental minimum fluidization velocity in a fluidized bed, is a useful and sensitive method of measuring the tackiness tendency of film-coated pellets.

  7. [Preparation and pharmacokinetic evaluation of long-acting injectable oily suspensions for ophiopogonis radix polysaccharide MDG-1].

    PubMed

    Shi, Xiao-Li; Yao, Chun-Xia; Lin, Xiao; Shen, Lan; Feng, Yi

    2014-07-01

    To evaluate in vivo pharmacokinetics of Ophiopogonis Radix polysaccharide MDG-1 oily suspension injection prepared with different prescriptions in rats, and explore the feasibility of the long-acting drug delivery of MDG-1 Injection by using the oily suspension drug release system. MDG-1 microparticles were prepared by the anti-solvent precipitation method. Their size and size distribution were characterized. Castor oil with a high viscosity or aluminum stearate were added into soybean oil with a low viscosity, in order to prepare oily media with different viscosities, detect their rheological properties and screen out superior prescriptions for in vivo evaluation. The average size of microparticles was 21.81 microm, and the span between them was 2.63. The in vivo evaluation was conducted for prescriptions of mixed oil (soybean oil/castor oil, 2: 3) and soybean oils gelled by 2% and 4% aluminium stearate. Among them, the prescription of soybean gelled by 4% aluminium stearate could significantly reduce C(max) and prolong the apparent t1/2, with the MDG-1 release time of several days. It is feasible to achieve the long-acting MDG-1 drug delivery by using oily media with a high viscosity.

  8. Diet Modulation is an Effective Complementary Agent in Preventing and Treating Breast Cancer Lung Metastasis

    PubMed Central

    Zhao, Xiangmin; Rezonzew, Gabriel; Wang, Dezhi; Siegal, Gene P.; Hardy, Robert W.

    2014-01-01

    A significant percentage of breast cancer victims will suffer from metastases indicating that new approaches to preventing breast cancer metastasis are thus needed. Dietary stearate and chemotherapy have been shown to reduce breast cancer metastasis. We tested the complementary use of dietary stearate with a taxol-based chemotherapy which work through separate mechanisms to reduce breast cancer metastasis. We therefore carried out a prevention study in which diets were initiated prior to human MDA-MB-435 cancer cells being injected into the host and a treatment study in which diets were combined with paclitaxel (PTX). Using an orthotopic athymic nude mouse model and three diets (corn oil control diet/CO, low fat /LF or stearate/ST) the prevention study demonstrated that the ST diet decreased the incidence of lung metastasis by 50% compared to both the LF and CO diets. The ST diet also reduced the number and size of metastatic lung nodules compared to the LF diet. Results of the treatment study indicated that both the CO and ST diets decreased the number of mice with lung metastasis compared to the LF diet. Both CO and ST also decreased the number of lung metastases per mouse compared to the LF diet however only the ST diet cohort was significant. Histomorphometric analysis of the lung tumor tissue indicated that the ST diet plus PTX decreased angiogenesis compared to the LF diet plus PTX. In conclusion these results support combining diet with chemotherapy in both treatment and prevention settings. PMID:24832758

  9. The effect of cores and coating dispersion composition on the mechanical and adhesion properties of hydroxypropyl methylcellulose films.

    PubMed

    Banovec, M; Planinsek, O; Vrecer, F

    2014-08-01

    The influence of different additives on the mechanical properties of hydroxypropyl methylcellulose (HPMC) free films was studied using tensile testing. Free films were prepared using the cast method and sliced into bands, and their tensile strength and maximal elongation at break was measured. The results showed that the addition of PEG 400 and polysorbate 80 into the coating formulation had the most influence on the films' mechanical properties compared to the HPMC film used as a control. Tablet cores composed of microcrystalline cellulose and lactose with and without Mg stearate and compressed at three different compression forces were tested for wettability with coating formulations containing PEG 400 and polysorbate 80. For formulations with no Mg stearate added, the contact angle decreased with increasing core hardness and it also coincided with greater adhesion force of the coating. The addition of Mg stearate in the core led to reduced adhesion of the film coating with PEG 400, whereas the influence on the adhesion force of the film coating containing polysorbate 80 was negligible. The results also show that the adhesion force, regardless of the tablet core formulation, is highest at medium core hardness.

  10. Adsorption of short-chain organic acids onto nearshore marine sediments

    NASA Astrophysics Data System (ADS)

    Sansone, Francis J.; Andrews, Christine C.; Okamoto, Mauri Y.

    1987-07-01

    The adsorption of acetate, butyrate, lactate, and stearate was measured using a clastic mud from Cape Lookout Bight N.C. (CLB), a lateritic muddy sand from Kahana Stream, Oahu, Hawaii (KS), and a fine carbonate sand from Waimanalo Beach, Oahu, (WB). Partition coefficients ( Kd, moles adsorbed per g of solid phase/moles dissolved per ml of porewater) ranged from 10 2.3 to ≤10 -3.0, and displayed the following trends: CLB > KS > WB, and stearate > acetate ˜- butyrate > lactate. The percent adsorption of the sediment organic acid pools showed similar trends: stearate, 99%; acetate, 9-23%; butyrate, 5-23%; lactate, ≤0.2-7%. These results reflected the relatively nonpolar nature of the sand surfaces in WB and KS sediments, and the polarities of the organic acids. Kd was approximately constant for each organic acid-sediment combination over a dissolved organic acid concentration range of 10 7, using concentrations between 1M and 10 -14 M. This constancy over a wide porewater concentration range suggested that adsorption was not limited by the availability of surface adsorption sites.

  11. VB12-coated Gel-Core-SLN containing insulin: Another way to improve oral absorption.

    PubMed

    He, Haibing; Wang, Puxiu; Cai, Cuifang; Yang, Rui; Tang, Xing

    2015-09-30

    To improve the oral absorption of insulin, a novel carrier of Vitamin B12 (VB12) gel core solid lipid nanopaticles (Gel-Core-SLN, GCSLN) was designed with a gel core, lipid matrix and VB12-coated surface. VB12-stearate was synthesized and characterized by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). Sol-gel conversion following ultrasonic heating and double emulsion technology were combined to implant the insulin-containing gel into solid lipid nanoparticles (SLN). The influence of the mode of administration, food, the amount of VB12-stearate and the particle size on the oral absorption of insulin incorporated in the VB12-GCSLN was investigated. The determined partition coefficient (LogP) of VB12-stearate in a dichloromethane (DCM)-water system was 3.4. This new structure of VB12-GCSLN had higher insulin encapsulation efficiency (EE) of 55.9%, a lower burst release of less than 10% in the first 2h. In vivo studies demonstrated that stronger absorption of insulin with a relative pharmacological availability (PA) of 9.31% compared with the normal insulin-loaded SLN and GCSLN and fairly stable blood glucose levels up to 12h were maintained without any sharp fluctuations. This study suggests that VB12-GCSLN containing insulin appears to be a promising nano carrier for oral delivery of biomacromolecules with relatively high pharmacological availability. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Variability of some diterpene esters in coffee beverages as influenced by brewing procedures.

    PubMed

    Moeenfard, Marzieh; Erny, Guillaume L; Alves, Arminda

    2016-11-01

    Several coffee brews, including classical and commercial beverages, were analyzed for their diterpene esters content (cafestol and kahweol linoleate, oleate, palmitate and stearate) by high performance liquid chromatography with diode array detector (HPLC-DAD) combined with spectral deconvolution. Due to the coelution of cafestol and kahweol esters at 225 nm, HPLC-DAD did not give accurate quantification of cafestol esters. Accordingly, spectral deconvolution was used to deconvolve the co-migrating profiles. Total cafestol and kahweol esters content of classical coffee brews ranged from 5-232 to 2-1016 mg/L, respectively. Commercial blends contained 1-54 mg/L of total cafestol esters and 2-403 mg/L of total kahweol esters. Boiled coffee had the highest diterpene esters content, while filtered and instant brews showed the lowest concentrations. However, individual diterpene esters content was not affected by brewing procedure as in terms of kahweol esters, kahweol palmitate was the main compound in all samples, followed by kahweol linoleate, oleate and stearate. Higher amounts of cafestol palmitate and stearate were also observed compared to cafestol linoleate and cafestol oleate. The ratio of diterpene esters esterified with unsaturated fatty acids to total diterpene esters was considered as measure of their unsaturation in analyzed samples which varied from 47 to 52%. Providing new information regarding the diterpene esters content and their distribution in coffee brews will allow a better use of coffee as a functional beverage.

  13. Alcohol dose dumping: The influence of ethanol on hot-melt extruded pellets comprising solid lipids.

    PubMed

    Jedinger, N; Schrank, S; Mohr, S; Feichtinger, A; Khinast, J; Roblegg, E

    2015-05-01

    The objective of the present study was to investigate interactions between alcohol and hot-melt extruded pellets and the resulting drug release behavior. The pellets were composed of vegetable calcium stearate as matrix carrier and paracetamol or codeine phosphate as model drugs. Two solid lipids (Compritol® and Precirol®) were incorporated into the matrix to form robust/compact pellets. The drug release characteristics were a strong function of the API solubility, the addition of solid lipids, the dissolution media composition (i.e., alcohol concentration) and correspondingly, the pellet wettability. Pellets comprising paracetamol, which is highly soluble in ethanol, showed alcohol dose dumping regardless of the matrix composition. The wettability increased with increasing ethanol concentrations due to higher paracetamol solubilities yielding increased dissolution rates. For pellets containing codeine phosphate, which has a lower solubility in ethanol than in acidic media, the wettability was a function of the matrix composition. Dose dumping occurred for formulations comprising solid lipids as they showed increased wettabilities with increasing ethanol concentrations. In contrast, pellets comprising calcium stearate as single matrix component showed robustness in alcoholic media due to wettabilities that were not affected by the addition of ethanol. The results clearly indicate that the physico-chemical properties of the drug and the matrix systems are crucial for the design of ethanol-resistant dosage forms. Moreover, hydrophobic calcium stearate can be considered a suitable matrix system that minimizes the risk of ethanol-induced dose dumping for certain API's.

  14. Therapy of Staphylococcal Infections in Monkeys

    PubMed Central

    Carlisle, Harold N.; Saslaw, Samuel

    1971-01-01

    Intravenous inoculation of a penicillin-resistant, phage type 80/81 staphylococcus caused lethal infection in six of eight untreated monkeys. Daily intragastric administration of clindamycin hydrochloride and erythromycin stearate and intramuscular inoculation of clindamycin-2-phosphate and methicillin, all at a dose level of 50 mg/kg, was followed by mortalities of one of eight, one of eight, none of eight, and one of eight monkeys, respectively. Duration of obvious acute illness in surviving monkeys and time required for complete recovery were not significantly different in the four therapy groups with the exception that duration of acute illness in monkeys treated with clindamycin-2-phosphate (mean, 4.1 days) was significantly shorter than in monkeys given erythromycin stearate (mean, 7.1 days). In vitro sensitivity data and serum antibacterial levels would suggest that methicillin would be the least effective therapeutically, followed by erythromycin stearate and the two clindamycin preparations in that order. However, this prediction was not fulfilled in these studies in experimentally infected monkeys. PMID:4994902

  15. Fatty acids alter monolayer integrity, paracellular transport, and iron uptake and transport in Caco-2 cells.

    PubMed

    Droke, Elizabeth A; Briske-Anderson, Mary; Lukaski, Henry C

    2003-12-01

    The Caco-2 cell line was used as a model to determine if the type of fatty acid, unsaturated versus saturated, differentially altered the uptake and transport of iron in the human intestine and if the changes were the result of alterations in monolayer integrity and paracellular transport. Cells were cultured in either a lower-iron or normal-iron medium and incubated with a bovine serum albumin control, linoleate, oleate, palmatate, or stearate. Oleate, palmatate, and stearate enhanced (p < 0.05) iron uptake in cells grown in lower iron. The fatty acid effect on iron uptake by cells grown in normal iron was not as pronounced. Iron transport was not affected (p > 0.05) by an interaction between the type of medium (iron concentration) and the type of fatty acid. Iron transport was enhanced (p < 0.05) with palmatate and stearate. Various indicators of monolayer integrity and paracellular transport were also affected by the fatty acids, thus impacting iron uptake and transport. These results indicate that oleate, palmatate, and stearic can enhance iron uptake and transport; however, this enhancement may be the result of alterations in the integrity of the intestine.

  16. Mechanical properties of potato starch modified by moisture content and addition of lubricant

    NASA Astrophysics Data System (ADS)

    Stasiak, Mateusz; Molenda, Marek; Horabik, Józef; Mueller, Peter; Opaliński, Ireneusz

    2014-10-01

    Laboratory testing was conducted to deliver a set of characteristics of structure and mechanical properties of pure starch and starch with an addition of a lubricant - magnesium stearate. Considerable influence of moisture content of potato starch was found in the case of density, parameters of internal friction, coefficients of wall friction and flowability. Elasticity was found to be strongly influenced by water content of the material. Addition of magnesium stearate affected density and parameters of flowability, internal friction and elasticity. Bulk density increased from 604 to 774 kg m-3 with decrease in moisture content of potato starch from 17 to for 6%. Addition of magnesium stearate resulted in approximately 10% decrease in bulk density. Angle of internal friction obtained for 10 kPa of consolidation stress decreased from 33 to 24º with increase in moisture content, and to approximately 22º with addition of the lubricant. With an increase of moisture content from 6 to 18% and with addition of the lubricant, the modulus of elasticity during loading decreased from approximately 1.0 to 0.1 MPa. Modulus of elasticity during unloading was found in the range from 19 to 42 MPa and increased with increase of moisture content and amount of lubricant.

  17. Biodegradable polymers derived from renewable resources: Highly branched copolymers of itaconic anhydride

    NASA Astrophysics Data System (ADS)

    Wallach, Joshua Andrew

    In an effort to design cyclic anhydride containing polymers that are derived from renewable resources and have biodegradable characteristics, three copolymer systems using itaconic anhydride have been studied. Two of the systems were copolymers with stearate based monomers; vinyl stearate and stearyl methacrylate, while the third was a copolymer with a methacrylate terminated poly (lactic acid) (PLA) macromonomer. For the stearate systems, stearyl methacrylate showed good copolymerization with equal conversions for both monomers. On the other hand vinyl stearate did not show as good results due to its decreased reactivity, which resulted in a copolymer highly enriched in itaconic anhydride with significant amounts of unreacted vinyl stearate under all copolymer compositions. These differing results were confirmed through analysis of reactivity ratios showing a results that are more favorable for copolymerization for the methacrylate system. Copolymers from both systems showed single melting transitions in a precarious range of 45--50°C arising from the stearyl side groups, though after quenching from the melt this shifted to below room temperature. Anhydride retention was confirmed through structural analysis. Similar to the stearyl methacrylate system, methacrylate terminated PLA macromonomers were copolymerized with itaconic anhydride. PLA's acceptance as a biodegradable material derived from renewable resources, make it a viable choice, with which to design anhydride containing copolymers. Good copolymerization was shown for all compositions studied with retention of the anhydride, though at high itaconic anhydride concentrations conversions were reduced significantly. Copolymers showed glass transition temperatures ranging from 32°C for 85 mole % PLA macromonomer to 73°C for 85 mole % itaconic anhydride. An effort to produce PLA macromonomers through a process of chemical recycling commercial PLA was also undertaken. Promising results were obtained showing

  18. Formulation strategies to modulate the topical delivery of anti-inflammatory compounds.

    PubMed

    Puglia, Carmelo; Rizza, Luisa; Offerta, Alessia; Gasparri, Franco; Giannini, Valentina; Bonina, Francesco

    2013-01-01

    The aim of this study was to assess the ability of some vehicles (emulsion and emulgel), containing hydrogenated lecithin as penetration enhancer, in increasing the percutaneous absorption of the two model compounds dipotassium glycyrrhizinate (DG) and stearyl glycyrrhetinate (SG). Furthermore SG-loaded solid lipid nanoparticles (SLNs) were prepared and the effect of this vehicle on SG permeation profile was evaluated as well. Percutaneous absorption has been studied in vitro, using excised human skin membranes (i.e., stratum corneum epidermis or [SCE]), and in vivo, determining their anti-inflammatory activity. From the results obtained, the use of both penetration enhancers and SLNs resulted in being valid tools to optimize the topical delivery of DG and SG. Soy lecithin guaranteed an increase in the percutaneous absorption of the two activities and a rapid anti-inflammatory effect in in vivo experiments, whereas SLNs produced an interesting delayed and sustained release of SG.

  19. Identification and Chemical Standardization of Licorice Raw Materials and Dietary Supplements Using UHPLC-MS/MS.

    PubMed

    Li, Guannan; Nikolic, Dejan; van Breemen, Richard B

    2016-10-04

    Defined as the roots and underground stems of principally three Glycyrrhiza species, G. glabra L., G.uralensis Fish. ex DC. and G. inflata Batalin, licorice has been used as a medicinal herb for millennia and is marketed as root sticks, powders and extracts. Identity tests described in most pharmacopeial monographs enabled the distinction of Glycyrrhiza species. Accordingly, an ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) assay using the method of standard addition was developed to quantify 14 licorice components (liquiritin, isoliquiritin, liquiritin apioside, isoliquiritin apioside, licuraside, liquiritigenin, isoliquiritigenin, glycyrrhizin, glycyrrhetinic acid, glabridin, glycycoumarin, licoricidin, licochalcone A, and p-hydroxybenzylmalonic acid), representing several natural product classes including chalcones, flavanones, saponins, and isoflavonoids. Using this approach, G. glabra, G. uralensis and G. inflata in a variety of forms including root powders and extracts as well as complex dietary supplements could be differentiated and chemically standardized without concerns due to matrix effects.

  20. Plant Natural Compounds with Antibacterial Activity towards Common Pathogens of Pond-Cultured Channel Catfish (Ictalurus punctatus)

    PubMed Central

    Schrader, Kevin K.

    2010-01-01

    The bacteria Edwardsiella ictaluri and Flavobacterium columnare cause enteric septicemia and columnaris disease, respectively, in channel catfish (Ictalurus punctatus). Natural therapeutants may provide an alternative to current management approaches used by producers. In this study, a rapid bioassay identified plant compounds as potential therapeutants. Chelerythrine chloride and ellagic acid were the most toxic toward E. ictaluri, with 24-h IC50 of 7.3 mg/L and 15.1 mg/L, respectively, and MIC of 2.1 mg/L and 6.5 mg/L, respectively. Chelerythrine chloride, ellagic acid, β-glycyrrhetinic acid, sorgoleone, and wogonin were the most toxic towards two genomovars of F. columnare, and wogonin had the strongest antibacterial activity (MIC = 0.3 mg/L). PMID:22069655

  1. Anti-allergic effect of bryonolic acid from Luffa cylindrica cell suspension cultures.

    PubMed

    Tanaka, S; Uno, C; Akimoto, M; Tabata, M; Honda, C; Kamisako, W

    1991-12-01

    The anti-allergic activity of bryonolic acid (1) isolated from the cultured cells of Luffa cylindrica L. (Cucurbitaceae) was compared with that of glycyrrhetinic acid (2), the aglycone of glycyrrhizin from licorice. Compound 1, when administered to rats intraperitoneally at a dose of 600 mg/kg, inhibited homologous passive cutaneous anaphylaxis more strongly than 2 at the same dose. Compound 1 also significantly inhibited delayed hypersensitivity in mice which could not be inhibited by 2. In contrast to 2, 1 showed not only little toxicity but no visible side effects on mice, without impairing the activity of the hepatic enzyme (4,5 beta-dihydrocortisone:NADP+ delta 4-oxidoreductase) involved in steroid catabolism.

  2. Synthesis of (-)-epicatechin 3-(3-O-methylgallate) and (+)-catechin 3-(3-O-methylgallate), and their anti-inflammatory activity.

    PubMed

    Iijima, Takashi; Mohri, Yoshihiro; Hattori, Yasunao; Kashima, Atsushi; Kamo, Tsunashi; Hirota, Mitsuru; Kiyota, Hiromasa; Makabe, Hidefumi

    2009-04-01

    A concise synthesis of (-)-epicatechin 3-(3-O-methylgallate) (1; ECG3''Me), which is a minor constituent of tea, and (+)-catechin 3-(3-O-methylgallate) (2; CG3''Me) via condensation of equimolar amount of catechin and gallate derivatives has been achieved. The anti-inflammatory effect of the synthetic compounds on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation of mouse ears was examined. Compounds 1 and 2 suppressed the TPA-induced inflammation of mouse ears by 50 and 43%, respectively, at a dose of 200 microg. Their activities are stronger than those of indomethacin and glycyrrhetinic acid, the normally used anti-inflammatory agents.

  3. Utilization of [11C]phosgene for radiosynthesis of N-(2-{3-[3,5-bis(trifluoromethyl)]phenyl[11C]ureido}ethyl)glycyrrhetinamide, an inhibitory agent for proteasome and kinase in tumors.

    PubMed

    Asakawa, Chiharu; Ogawa, Masanao; Fujinaga, Masayuki; Kumata, Katsushi; Xie, Lin; Yamasaki, Tomoteru; Yui, Joji; Fukumura, Toshimitsu; Zhang, Ming-Rong

    2012-06-01

    N-(2-{3-[3,5-Bis(trifluoromethyl)]phenylureido}ethyl)glycyrrhetinamide (2), an ureido-substituted derivative of glycyrrhetinic acid (1), has been reported to display potent inhibitory activity for proteasome and kinase, which are overexpressed in tumors. In this study, we labeled this unsymmetrical urea 2 using [(11)C]phosgene ([(11)C]COCl(2)) as a labeling agent with the expectation that [(11)C]2 could become a positron emission tomography ligand for the imaging of proteasome and kinase in tumors. The strategy for the radiosynthesis of [(11)C]2 was to react hydrochloride of 3,5-bis(trifluoromethyl)aniline (4·HCl) with [(11)C]COCl(2) to possibly give isocyanate [(11)C]6, followed by the reaction of [(11)C]6 with N-(2-aminoethyl)glycyrrhetinamide (3). Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Adenoviral delivery of human connexin37 induces endothelial cell death through apoptosis.

    PubMed

    Seul, Kyung H; Kang, Keum Y; Lee, Kyung S; Kim, Suhn H; Beyer, Eric C

    2004-07-09

    Gap junction channels formed of connexins directly link the cytoplasm of adjacent cells and have been implicated in intercellular signaling that may regulate the functions of vascular cells. To facilitate connexin manipulation and analysis of their roles in adult endothelial cells, we developed adenoviruses containing the vascular connexins (Cx37, Cx40, and Cx43). We infected cultured human umbilical vein endothelial cells with control or connexin adenoviruses. Connexin expression was verified by immunoblotting and immunofluorescence. Infection with the Cx37 adenovirus (but not control or other connexin adenoviruses) led to a dose-dependent death of the endothelial cells that was partially antagonized by the gap junction blocker alpha-glycyrrhetinic acid and altered the intercellular transfer of Lucifer yellow and neurobiotin. Cell morphology, Annexin V and TUNEL staining, and caspase 3 assays all implicated apoptosis in the cell death. These data suggest that connexin-specific alterations of intercellular communication may modulate endothelial cell growth and death.

  5. (+)-Methyl 3β-acet­oxy-13-carb­oxy-19-hy­droxy-11-oxo-C-norolean-18-en-30-oate γ-lactone

    PubMed Central

    Gaware, Rawindra; Czollner, Laszlo; Jordis, Ulrich; Mereiter, Kurt

    2010-01-01

    The title compound, C33H46O7, is an unusual oxydation product of the therapeutic agent glycyrrhetinic acid that has, in comparison to the latter, a distinctly altered triterpene structure with one five- and four six-membered carbocycles complemented by a γ-lactone ring with a spiro-junction and a ring double bond. The junction between the five-membered ring C, a cyclo­penta­none ring, and the six-membered ring D, previously in question, was found to be cis, confirming earlier structure assignments based solely on chemical transformations. In the solid state, the compound exhibits five intra- and four inter­molecular C—H⋯O inter­actions with H⋯O distances less than or equal to 2.70 Å and C—H⋯O greater than 100°. PMID:21587575

  6. Phytosteroids beyond estrogens: Regulators of reproductive and endocrine function in natural products.

    PubMed

    Dean, Matthew; Murphy, Brian T; Burdette, Joanna E

    2017-02-15

    Foods and botanical supplements can interfere with the endocrine system through the presence of phytosteroids - chemicals that interact with steroids receptors. Phytoestrogens are well studied, but compounds such as kaempferol, apigenin, genistein, ginsenoside Rf, and glycyrrhetinic acid have been shown to interact with non-estrogen nuclear receptors. These compounds can have agonist, antagonist, or mixed agonist/antagonist activity depending on compound, receptor, cell line or tissue, and concentration. Some phytosteroids have also been shown to inhibit steroid metabolizing enzymes, resulting in biological effects through altered endogenous steroid concentrations. An interesting example, compound A (4-[1-chloro-2-(methylamino)ethyl]phenyl acetate hydrochloride (1:1)) is a promising selective glucocorticoid receptor modulator (SGRM) based on a phytosteroid isolated from Salsola tuberculatiformis Botschantzev. Given that $6.9 billion of herbal supplements are sold each year, is clear that further identification and characterization of phytosteroids is needed to ensure the safe and effective use of botanical supplements.

  7. Glycyrrhizic Acid in the Treatment of Liver Diseases: Literature Review

    PubMed Central

    Li, Jian-yuan; Cao, Hong-yan; Cheng, Gen-hong; Sun, Ming-yu

    2014-01-01

    Glycyrrhizic acid (GA) is a triterpene glycoside found in the roots of licorice plants (Glycyrrhiza glabra). GA is the most important active ingredient in the licorice root, and possesses a wide range of pharmacological and biological activities. GA coupled with glycyrrhetinic acid and 18-beta-glycyrrhetic acid was developed in China or Japan as an anti-inflammatory, antiviral, and antiallergic drug for liver disease. This review summarizes the current biological activities of GA and its medical applications in liver diseases. The pharmacological actions of GA include inhibition of hepatic apoptosis and necrosis; anti-inflammatory and immune regulatory actions; antiviral effects; and antitumor effects. This paper will be a useful reference for physicians and biologists researching GA and will open the door to novel agents in drug discovery and development from Chinese herbs. With additional research, GA may be more widely used in the treatment of liver diseases or other conditions. PMID:24963489

  8. Influence of Jiegeng on Pharmacokinetic Properties of Flavonoids and Saponins in Gancao.

    PubMed

    Mao, Yancao; Peng, Linxiu; Kang, An; Xie, Tong; Xu, Jianya; Shen, Cunsi; Ji, Jianjian; Di, Liuqing; Wu, Hao; Shan, Jinjun

    2017-09-21

    Jiegeng Gancao decoction, which is composed of Jiegeng and Gancao at a weight ratio of 1:2, was widely used for treating pharyngalgia and cough for thousands of years. Our previous work indicated that Gancao could increase the systemic exposure of platycodin D and deapio-platycodin D, two main components in Jiegeng. However, whether Jiegeng could alter the pharmacokinetics of the main compounds in Gancao is still unknown. Thus, the purpose of this study was to compare the oral pharmacokinetics of flavonoids and saponins from Gancao alone vs. after co-administration with Jiegeng. Furthermore, Caco-2 cell transport and fecal hydrolysis were investigated to explain the altered pharmacokinetic properties. Pharmacokinetics results suggested that the bioavailability of liquiritin, isoliquiritin, glycyrrhizin and its metabolite, glycyrrhetinic acid, could be improved while bioavailability of liquiritigenin and isoliquiritigenin deteriorated when co-administered with Jiegeng. The Caco-2 transport study showed no significant difference of the Papp values of the main components in Jiegeng Gancao decoction when compared with those in Gancao decoction (p > 0.05). The in vitro metabolism study suggested that saponins and flavonoids glycosides in Gancao were influenced and the metabolic characteristics of most ingredients were consistent with pharmacokinetic results, such as liquiritin and glycyrrhetinic acid. The hydrolysis of liquiritigenin and glycyrrhizin observed with fecal lysate in vitro appeared consistent with the oral pharmacokinetics. Based on experiments, the pharmacokinetic profiles of six components in Gancao were influenced by Jiegeng. The metabolic process might partially contribute to the altered pharmacokinetic behavior. The metabolism of some components of Gancao appeared to be inhibited when coadministered with Jiegeng, possibly by the Jiegeng constituent platycodin.

  9. Functional role of gap junctions in cytokine-induced leukocyte adhesion to endothelium in vivo

    PubMed Central

    Véliz, Loreto P.; González, Francisco G.; Duling, Brian R.; Sáez, Juan C.; Boric, Mauricio P.

    2008-01-01

    To assess the hypothesis that gap junctions (GJs) participate on leukocyte-endothelium interactions in the inflammatory response, we compared leukocyte adhesion and transmigration elicited by cytokine stimulation in the presence or absence of GJ blockers in the hamster cheek pouch and also in the cremaster muscle of wild-type (WT) and endothelium-specific connexin 43 (Cx43) null mice (Cx43e−/−). In the cheek pouch, topical tumor necrosis factor-α (TNF-α; 150 ng/ml, 15 min) caused a sustained increment in the number of leukocytes adhered to venular endothelium (LAV) and located at perivenular regions (LPV). Superfusion with the GJ blockers 18-α-glycyrrhetinic acid (AGA; 75 μM) or 18-β-glycyrrhetinic acid (50 μM) abolished the TNF-α-induced increase in LAV and LPV; carbenoxolone (75 μM) or oleamide (100 μM) reduced LAV by 50 and 75%, respectively, and LPV to a lesser extent. None of these GJ blockers modified venular diameter, blood flow, or leukocyte rolling. In contrast, glycyrrhizin (75 μM), a non-GJ blocker analog of AGA, was devoid of effect. Interestingly, when AGA was removed 90 min after TNF-α stimulation, LAV started to rise at a similar rate as in control. Conversely, application of AGA 90 min after TNF-α reduced the number of previously adhered cells. In WT mice, intrascrotal injection of TNF-α (0.5 μg/0.3 ml) increased LAV (fourfold) and LPV (threefold) compared with saline-injected controls. In contrast to the observations in WT animals, TNF-α stimulation did not increase LAV or LPV in Cx43e−/− mice. These results demonstrate an important role for GJ communication in leukocyte adhesion and transmigration during acute inflammation in vivo and further suggest that endothelial Cx43 is key in these processes. PMID:18599597

  10. GnRH Episodic Secretion Is Altered by Pharmacological Blockade of Gap Junctions: Possible Involvement of Glial Cells.

    PubMed

    Pinet-Charvet, Caroline; Geller, Sarah; Desroziers, Elodie; Ottogalli, Monique; Lomet, Didier; Georgelin, Christine; Tillet, Yves; Franceschini, Isabelle; Vaudin, Pascal; Duittoz, Anne

    2016-01-01

    Episodic release of GnRH is essential for reproductive function. In vitro studies have established that this episodic release is an endogenous property of GnRH neurons and that GnRH secretory pulses are associated with synchronization of GnRH neuron activity. The cellular mechanisms by which GnRH neurons synchronize remain largely unknown. There is no clear evidence of physical coupling of GnRH neurons through gap junctions to explain episodic synchronization. However, coupling of glial cells through gap junctions has been shown to regulate neuron activity in their microenvironment. The present study investigated whether glial cell communication through gap junctions plays a role in GnRH neuron activity and secretion in the mouse. Our findings show that Glial Fibrillary Acidic Protein-expressing glial cells located in the median eminence in close vicinity to GnRH fibers expressed Gja1 encoding connexin-43. To study the impact of glial-gap junction coupling on GnRH neuron activity, an in vitro model of primary cultures from mouse embryo nasal placodes was used. In this model, GnRH neurons possess a glial microenvironment and were able to release GnRH in an episodic manner. Our findings show that in vitro glial cells forming the microenvironment of GnRH neurons expressed connexin-43 and displayed functional gap junctions. Pharmacological blockade of the gap junctions with 50 μM 18-α-glycyrrhetinic acid decreased GnRH secretion by reducing pulse frequency and amplitude, suppressed neuronal synchronization and drastically reduced spontaneous electrical activity, all these effects were reversed upon 18-α-glycyrrhetinic acid washout.

  11. Enzymatic biotransformation of terpenes as bioactive agents.

    PubMed

    Sultana, Nighat; Saify, Zafar Saeed

    2013-12-01

    The plant-derived terpenoids are considered to be the most potent anticancer, anti-inflammatory and anticarcinogenic compounds known. Enzymatic biotransformation is a very useful approach to expand the chemical diversity of natural products. Recent enzymatic biotransformation studies on terpenoids have resulted in the isolation of novel compounds. 14-hydroxy methyl caryophyllene oxide produced from caryophyllene oxide showed a potent inhibitory activity against the butyryl cholinesterase enzyme, and was found to be more potent than parent caryophyllene oxide. The metabolites 3β,7β-dihydroxy-11-oxo-olean-12-en-30-oic acid, betulin, betulonic acid, argentatin A, incanilin, 18β glycyrrhetinic acid, 3,11-dioxo-olean-12-en-30-oic acid produced from 18β glycyrrhetinic acid were screened against the enzyme lipoxygenase. 3,11-Dioxo-olean-12-en-30-oic acid, was found to be more active than the parent compound. The metabolites 3β-hydroxy sclareol 18α-hydroxy sclareol, 6α,18α-dihydroxy sclareol, 11S,18α-dihydroxy sclareol, and 1β-hydroxy sclareol and 11S,18α-dihydroxy sclareol produced from sclareol were screened for antibacterial activity. 1β-Hydroxy sclareol was found to be more active than parent sclareol. There are several reports on natural product enzymatic biotransformation, but few have been conducted on terpenes. This review summarizes the classification, advantages and agents of enzymatic transformation and examines the potential role of new enzymatically transformed terpenoids and their derivatives in the chemoprevention and treatment of other diseases.

  12. Effects of a Non-Conservative Sequence on the Properties of β-glucuronidase from Aspergillus terreus Li-20

    PubMed Central

    Liu, Yanli; Huangfu, Jie; Qi, Feng; Kaleem, Imdad; E, Wenwen; Li, Chun

    2012-01-01

    We cloned the β-glucuronidase gene (AtGUS) from Aspergillus terreus Li-20 encoding 657 amino acids (aa), which can transform glycyrrhizin into glycyrrhetinic acid monoglucuronide (GAMG) and glycyrrhetinic acid (GA). Based on sequence alignment, the C-terminal non-conservative sequence showed low identity with those of other species; thus, the partial sequence AtGUS(-3t) (1–592 aa) was amplified to determine the effects of the non-conservative sequence on the enzymatic properties. AtGUS and AtGUS(-3t) were expressed in E. coli BL21, producing AtGUS-E and AtGUS(-3t)-E, respectively. At the similar optimum temperature (55°C) and pH (AtGUS-E, 6.6; AtGUS(-3t)-E, 7.0) conditions, the thermal stability of AtGUS(-3t)-E was enhanced at 65°C, and the metal ions Co2+, Ca2+ and Ni2+ showed opposite effects on AtGUS-E and AtGUS(-3t)-E, respectively. Furthermore, Km of AtGUS(-3t)-E (1.95 mM) was just nearly one-seventh that of AtGUS-E (12.9 mM), whereas the catalytic efficiency of AtGUS(-3t)-E was 3.2 fold higher than that of AtGUS-E (7.16 vs. 2.24 mM s−1), revealing that the truncation of non-conservative sequence can significantly improve the catalytic efficiency of AtGUS. Conformational analysis illustrated significant difference in the secondary structure between AtGUS-E and AtGUS(-3t)-E by circular dichroism (CD). The results showed that the truncation of the non-conservative sequence could preferably alter and influence the stability and catalytic efficiency of enzyme. PMID:22347419

  13. Screening of gap junction antagonists on dye coupling in the rabbit retina

    PubMed Central

    PAN, FENG; MILLS, STEPHEN L.; MASSEY, STEPHEN C.

    2008-01-01

    Many cell types in the retina are coupled via gap junctions and so there is a pressing need for a potent and reversible gap junction antagonist. We screened a series of potential gap junction antagonists by evaluating their effects on dye coupling in the network of A-type horizontal cells. We evaluated the following compounds: meclofenamic acid (MFA), mefloquine, 2-aminoethyldiphenyl borate (2-APB), 18-α-glycyrrhetinic acid, 18-β-glycyrrhetinic acid (18-β-GA), retinoic acid, flufenamic acid, niflumic acid, and carbenoxolone. The efficacy of each drug was determined by measuring the diffusion coefficient for Neurobiotin (Mills & Massey, 1998). MFA, 18-β-GA, 2-APB and mefloquine were the most effective antagonists, completely eliminating A-type horizontal cell coupling at a concentration of 200 μM. Niflumic acid, flufenamic acid, and carbenoxolone were less potent. Additionally, carbenoxolone was difficult to wash out and also may be harmful, as the retina became opaque and swollen. MFA, 18-β-GA, 2-APB and mefloquine also blocked coupling in B-type horizontal cells and AII amacrine cells. Because these cell types express different connexins, this suggests that the antagonists were relatively non-selective across several different types of gap junction. It should be emphasized that MFA was water-soluble and its effects on dye coupling were easily reversible. In contrast, the other gap junction antagonists, except carbenoxolone, required DMSO to make stock solutions and were difficult to wash out of the preparation at the doses required to block coupling in A-type HCs. The combination of potency, water solubility and reversibility suggest that MFA may be a useful compound to manipulate gap junction coupling. PMID:17711600

  14. Evaluation of cocoa butter as potential lubricant for coprocessing in pharmaceutical tablets.

    PubMed

    Adeagbo, Adebolu Adewole; Alebiowu, Gbenga

    2008-01-01

    The lubricant activity of cocoa butter coprocessed with magnesium stearate plus talc (CMT) was compared with magnesium stearate plus talc (MT) using flow and compressional characteristics of paracetamol granules and mechanical properties of their tablets as assessment parameters. The flow of the granules quantified as Hausner's ratio, Carr's index, and angle of repose showed that CMT has a higher ability than MT to reduce densification of granules due to vibration. Compressional characteristics analyzed using density measurements and the Heckel and Kawakita plots revealed that CMT did not facilitate the increase in the densification of the granules during the filling and at low pressures, D(b). Also, CMT reduced the plastic deformation of the granules measured by the P(y)-yield pressure at onset of plastic deformation and P(k)-yield pressure of deformation under compression. The mechanical properties determined by the tensile strength, T, and brittle fracture index, BFI, of the tablets produced were affected by CMT. The T and BFI of tablets with CMT were lower than those of MT. The results suggest that though CMT lowered the plasticity of the granules, it improved their flow rate and assisted in producing tablets with fewer tendencies to cap or laminate. This work concluded that cocoa butter, an inexpensive and easily available lipid, is an effective and viable lubricant that can be co-processed with magnesium stearate/talc mixture for an efficient lubrication of granules and may be useful in reducing lamination and capping in formulations that are susceptible to these 2 defects of tablets.

  15. Magnesium stearine production via direct reaction of palm stearine and magnesium hydroxide

    NASA Astrophysics Data System (ADS)

    Pratiwi, M.; Ylitervo, P.; Pettersson, A.; Prakoso, T.; Soerawidjaja, T. H.

    2017-06-01

    The fossil oil production could not compensate with the increase of its consumption, because of this reason the renewable alternative energy source is needed to meet this requirement of this fuel. One of the methods to produce hydrocarbon is by decarboxylation of fatty acids. Vegetable oil and fats are the greatest source of fatty acids, so these can be used as raw material for biohydrocarbon production. From other researchers on their past researchs, by heating base soap from divalent metal, those metal salts will decarboxylate and produce hydrocarbon. This study investigate the process and characterization of magnesium soaps from palm stearine by Blachford method. The metal soaps are synthesized by direct reaction of palm stearine and magnesium hydroxide to produce magnesium stearine and magnesium stearine base soaps at 140-180°C and 6-10 bar for 3-6 hours. The operation process which succeed to gain metal soaps is 180°C, 10 bar, for 3-6 hours. These metal soaps are then compared with commercial magnesium stearate. Based on Thermogravimetry Analysis (TGA) results, the decomposition temperature of all the metal soaps were 250°C. Scanning Electron Microscope with Energy Dispersive X-ray (SEM-EDX) analysis have shown the traces of sodium sulphate for magnesium stearate commercial and magnesium hydroxide for both type of magnesium stearine soaps. The analysis results from Microwave Plasma-Atomic Emission Spectrometry (MP-AES) have shown that the magnesium content of magnesium stearine approximate with magnesium stearate commercial and lower compare with magnesium stearine base soaps. These experiments suggest that the presented saponification process method could produced metal soaps comparable with the commercial metal soaps.

  16. Dexamethasone-induced lipolysis increases the adverse effect of adipocytes on osteoblasts using cells derived from human mesenchymal stem cells.

    PubMed

    Wang, Dongqing; Haile, Azeb; Jones, Lynne C

    2013-04-01

    The increased bone marrow lipid deposition in steroid-associated bone loss diseases indicates that abnormalities in fat metabolism are associated with disease development. Recent studies have suggested that bone marrow adipocytes are secretory cells and that they may release substances that have an inhibitory effect on the differentiation and function of osteoblasts. We hypothesized that exposure of bone-marrow-derived adipocytes to corticosteroids exacerbates their deleterious effects on osteoblast metabolism and function. Adipocytes and osteoblasts derived from a human mesenchymal stem cell line (240L) were co-cultured in the absence of direct cell contact with or without dexamethasone treatment. After 6days of co-culture, osteoblasts demonstrated significantly lower levels of function based on lower mineralization, alkaline phosphatase activity and expression of osteogenic (Runx2, osteocalcin) mRNA marker. Dexamethasone treatment resulted in significantly lower levels of osteoblastic function compared with co-cultured cells without dexamethasone. Furthermore, conditioned media from dexamethasone-treated adipocytes induced a similar toxic effect and increased apoptosis involving activation of caspases 3/7 compared with conditioned media without dexamethasone treatment. Within the conditioned media, a substantial increase in the levels of leptin and two saturated fatty acids (FAs; stearate and palmitate) was observed after dexamethasone treatment. Although leptin supplementation failed to induce the inhibitory effect on osteoblasts, similar toxic results were produced with stearate and palmitate treatment, and an increase in intracellular reactive oxygen species was observed. Stearate- and palmitate-induced apoptosis was blocked by a reactive oxygen species scavenger pyrrolidine dithiocarbamate. These data show that saturated FAs secreted from adipocytes induce lipotoxic effects via mechanisms that may involve reactive oxygen species accumulation in osteoblasts

  17. Floating-pulsatile release multiparticulate system for chronopharmacotherapy: effect of some hydrophobic additives on the buoyancy and release behavior of particles.

    PubMed

    Maghsoodi, M

    2014-01-01

    A blend of floating and pulsatile principles of a drug delivery system would have the advantage that a drug can be released in the upper gastrointestinal (GI) tract after a lag period, which is anticipated for chronotherapy. In this study, microballoons were prepared by an emulsion solvent diffusion technique using Eudragit S100, and hydrophobic additive (magnesium stearate, stearic acid or talc) for time- and site-specific drug release of piroxicam. The effect of hydrophobic additives on the production yield of floating microparticles, buoyant ability for 8 h, release of drug in simulated GI fluids (simulated gastric fluid [SGF] and simulated intestinal fluid [SIF]), mean particle size, apparent particle density, encapsulation efficiency of drug and physical state of incorporated drug were studied. Both production yield and buoyancy of the microballoons were affected by additives in the following order: magnesium stearate, stearic acid>free-additive>talc. The observed difference in yield and the buoyancy of the microballoons could be attributed to the hydrophobic character of the additives and the shell rigidity of the obtained microballoons. Incorporation of hydrophobic additives in the microballoons was found to impart the desired release properties to the microballoons by providing a 2-phase release pattern with initial slow release (5-6%) through 8 h in SGF followed by rapid pulse release (>92%) in SIF through 15 min. The microballoons co-formulated with magnesium stearate or stearic acid, combining excellent buoyancy and suitable drug release pattern of piroxicam, could be useful in chronopharmacotherapy in arthritis.

  18. Products of the determination of the iodine value with iodine monobromide.

    PubMed

    Imming, Peter; Germershaus, Oliver

    2002-11-01

    The iodine value (iodine number) is an important analytical characteristic of fats and oils. Leading pharmacopeias determine it using iodine monobromide (Hanus method). We used methyl oleate as a simple analog of unsaturated triacylglycerols to identify the products. After performing the reaction in deuterated solvents under pharmacopeial conditions, NMR spectroscopy revealed the presence of the 9, 10-diiodo, 9, 10-dibromo, and 9, 10-bromoiodo adducts, leaving no educt olefin. The prescribed subsequent addition of potassium iodide led to the formation of methyl 9, 10-diiodo and bromoiodo stearate in equal amounts.

  19. Efficiency of metal activators of accelerated sulfur vulcanization

    SciTech Connect

    Duchacek, V.; Kuta, A.; Pribyl, P. )

    1993-01-20

    The effects of copper, mercury, nickel, zinc, cadmium, indium, magnesium, and calcium stearates on the course of N-cyclohexyl-2-benzthiazylsulphenamide-accelerated sulfur vulcanization of natural rubber have been investigated on the basis of curemeter measurements at 145 C. The differences in the efficiencies of these metal activators of accelerated sulfur vulcanization have been discussed from the points of view of the electron configurations of the metals and their affinities to sulfur. The authors attempted to determine why zinc oxide is generally accepted as the best metal vulcanization activator.

  20. The Giant Viper Mine Clearing Line Charge: Characterization of Energetic Materials

    DTIC Science & Technology

    1981-09-01

    grease) (DG29) Penta- erythritol 1.0 ± 0.3 1.15 Di-oleate, % (PEDO) 5 The procedures used for RDX was Military Standard MIL-C-401C except that the paraffin...lithium stearate was extracted with 80/20 benzene saturated with RDX and absolute ethanol. The penta- erythritol di-oleate was extracted with warm...DG29) Penta- erythritol Di-oleate, % 0.9 max 0.85 0.81 0.9 .62 (PEDO) Aluminum, % 15.0 ± 1.0 15.99 17.67 17.21 17.06 The results indicate that, although

  1. Study of the effect of γ-absorbed dose on degradation of polypropylene/starch-filled polymer containing photo-initiators by spectroscopic methods

    NASA Astrophysics Data System (ADS)

    Bagheri, Rouhollah.

    2009-09-01

    γ irradiated samples containing photo-initiators (PIs) with and without corn starch at 0-60 kGy were studied by UV spectrophotometer and FTIR. A linear decrease in the wavelength of absorbance maximum of each aromatic PI is observed by increase in the dose. The presence of starch in the sample caused a fluctuation of the absorptions. An increase in carbonyl formation due to the effect of a PI was detected. Ferric stearate and Irgacure 184 showed the highest and lowest effect respectively.

  2. Obtaining and Characterization of Polyolefin-Filled Calcium Carbonate Composites Modified with Stearic Acid

    NASA Astrophysics Data System (ADS)

    Croitoru, C.; Pascu, A.; Roata, I. C.; Stanciu, E. M.

    2017-06-01

    In order to obtain high performance calcium carbonate-reinforced HDPE and PP composites, the dispersibility and compatibility of the inorganic phase in the polymer has been achieved through surface treatment of the amorphous calcium carbonate filler with stearic acid. The surface coating of the inorganic phase has been proved by XRD and FTIR spectroscopy, through forming of an intermediate layer of calcium stearate which acts as a surfactant, efficient in providing an optimum compatibility with the dominatingly hydrophobic polymer matrix, as determined from the structural information obtained through samples cross-sections analysing.

  3. Evidence for vesicle formation from 1:1 nonionic surfactant span 60 and fatty alcohol mixtures in aqueous ethanol: potential delivery vehicle composition.

    PubMed

    Bandyopadhyay, Prasun; Neeta, N S

    2007-08-01

    A study of the self-organization of nonionic surfactant span 60 (sorbitan mono stearate) in presence of fatty alcohol (stearyl, cetyl and lauryl) is presented. When ethanolic solution of the surfactant-fatty alcohol (1:1) mixture is added in water spontaneous large unilamellar vesicles (LUV) are formed which may potentially be useful vehicles for drug delivery purposes. Vesicular suspension has been characterized by transmission electron microscopy, dynamic light scattering, confocal laser scanning microscopy, dye entrapment and release studies. Surface tension measurement indicates the suitability of fatty alcohols towards spontaneous vesicle formation from span 60.

  4. Lubrication in tablet formulations.

    PubMed

    Wang, Jennifer; Wen, Hong; Desai, Divyakant

    2010-05-01

    Theoretical aspects and practical considerations of lubrication in tablet compression are reviewed in this paper. Properties of the materials that are often used as lubricants, such as magnesium stearate, in tablet dosage form are summarized. The manufacturing process factors that may affect tablet lubrication are discussed. As important as the lubricants in tablet formulations are, their presence can cause some changes to the tablet physical and chemical properties. Furthermore, a detailed review is provided on the methodologies used to characterize lubrication process during tablet compression with relevant process analytical technologies. Finally, the Quality-by-Design considerations for tablet formulation and process development in terms of lubrication are discussed.

  5. Microwave-assisted synthesis of deuterium labeled estrogen fatty acid esters.

    PubMed

    Kiuru, Paula S; Wähälä, Kristiina

    2006-01-01

    Deuterated analogs of estrogen fatty acid esters are needed as internal standards for isotope dilution GC/MS analyses. We have developed a rapid and efficient synthesis for 2,4,16,16-D4-estrone palmitate, stearate, oleate, linoleate, and linolenate and the corresponding 2,4,16,16,17alpha-D5-estradiol fatty acid 17-mono and 3,17-diesters using analogous fatty acid chlorides or fatty acid anhydrides and 4-(dimethylamino)pyridine under microwave irradiation. Chemoselective hydrolysis of fatty acid diesters was carried out by KOH in t-BuOH.

  6. A solvothermal route to CdS nanocrystals

    NASA Astrophysics Data System (ADS)

    Gautam, Ujjal K.; Seshadri, Ram; Rao, C. N. R.

    2003-07-01

    A novel solvothermal route for the preparation of organic soluble CdS nanocrystals, involving the reaction of cadmium stearate with sulfur in the presence of tetralin has been described. Tetralin in the presence of S gives H 2S, getting aromatized to naphthalene. By using trioctylphosphineoxide as the capping agent, nanocrystals of 4 nm are obtained. Use of dodecanethiol cap results in 5 nm as well as 10 nm nanocrystals which can be separated readily. The nanocrystals have the cubic zinc blende structure and exhibit blue shifts of the absorption maximum.

  7. Preparation of PbS and PbSe nanocrystals by a new solvothermal route

    SciTech Connect

    Gautam, Ujjal K.; Seshadri, Ram

    2004-04-02

    A new solvothermal route for the preparation of nanocrystals of PbS and PbSe, involving the reaction of lead stearate with sulfur or selenium and tetralin (tetrahydronaphthalene) in toluene solvent is described. Tetralin in the presence of S/Se gives H{sub 2}S/H{sub 2}Se and gets aromatized to naphthalene. The nanocrystals have been characterized by powder X-ray diffraction and electron microscopy. Use of surfactant Triton X-100 (polyoxyethylene(10)isooctylphenyl ether) resulted in both nanorods and nanoparticles of PbSe. Capping by citric acid and malonic acid reduce the particle sizes to less than 10 nm.

  8. Hydrodeoxygenation of fatty acid esters catalyzed by Ni on nano-sized MFI type zeolites

    SciTech Connect

    Schreiber, Moritz W.; Rodriguez-Niño, Daniella; Gutiérrez, Oliver Y.; Lercher, Johannes A.

    2016-01-01

    The impact of support morphology and composition on the intrinsic activity of Ni supported on MFI-type zeolite was explored in the hydrodeoxygenation of methyl stearate, tristearate, and algae oil (mixture of triglycerides). The nano-sized structure of the support (self-pillared nanosheets) is beneficial for the activity of the catalysts. Higher Ni dispersion and concomitant higher reaction rates were obtained on nano-structured supports than on zeolite with conventional morphology. Rates normalized to accessible Ni atoms (TOF), however, varied little with support morphology. Acidity of the support increases the rate of Ni-catalyzed C-O hydrogenolysis per surface metal site.

  9. Enzyme-Catalyzed Regioselective Modification of Starch Nanoparticles

    SciTech Connect

    Chakraborty, Soma; Sahoo, Bishwabhusan; Teraoka, Iwao; Miller, Lisa M.; Gross, Richard A.

    2004-12-13

    The selective esterification of starch nanoparticles was performed using as catalyst Candida antartica Lipase B (CAL-B) in its immobilized (Novozym 435) and free (SP-525) forms. The starch nanoparticles were made accessible for acylation reactions by formation of Aerosol-OT (AOT, bis(2-ethylhexyl)sodium sulfosuccinate) stabilized microemulsions. Starch nanoparticles in microemulsions were reacted with vinyl stearate, ε-caprolactone, and maleic anhydride at 40 °C for 48 h to give starch esters with degrees of substitution (DS) of 0.8, 0.6, and 0.4, respectively. Substitution occurred regioselectively at the C-6 position of the glucose repeat units. Infrared microspectroscopy (IRMS) revealed that AOT-coated starch nanoparticles diffuse into the outer 50 μm shell of catalyst beads. Thus, even though CAL-B is immobilized within a macroporous resin, CAL-B is sufficiently accessible to the starch nanoparticles. When free CAL-B was incorporated along with starch within AOT-coated reversed micelles, CAL-B was also active and catalyzed the acylation with vinyl stearate (24 h, 40 °C) to give DS = 0.5. After removal of surfactant from the modified starch nanoparticles, they were dispersed in DMSO or water and were shown to retain their nanodimensions.

  10. Evaluation of drug-excipient interaction in the formulation of celecoxib tablets.

    PubMed

    Bozdağ-Pehlivan, Sibel; Subaşi, Birsel; Vural, Imran; Unlü, Nurşen; Capan, Yilmaz

    2011-01-01

    In the present study, the possible interactions between celecoxib and some excipients (colloidal silicon dioxide (Aerosil), microcrystalline cellulose (Avicel PH 102), lactose anhydrous, magnesium stearate, cross-povidone and talc) were evaluated by examining the pure drug or drug-excipient powder mixtures which were stored under different conditions (25 +/- 2 degrees C, 60% RH +/- 5% RH or 40 + 2 degrees C, 75% RH +/- 5% RH) and different period (30 or 60 days) using DSC, FT-IR and HPLC. In order to investigate the possibility of celecoxib-excipient interaction in aqueous medium, dispersions of the pure drug or drug in physical powder mixture (1:1 w/w) in water (1%, w/v) were also prepared and evaluated by FT-IR and HPLC at day 0 and day 7 (40 +/- 2 degrees C). The interaction between celecoxib and magnesium stearate or colloidal silicon dioxide were determined in the aqueous dispersions by FT-IR. Different tablet formulations with or without excipients tested were prepared, and assessed for drug dissolution and permeability.

  11. Purification and characterization of a novel cholesterol esterase from Pseudomonas aeruginosa, with its application to cleaning lipid-stained contact lenses.

    PubMed

    Sugihara, Akio; Shimada, Yuji; Nomura, Atsuo; Terai, Tadamasa; Imayasu, Masaki; Nagai, Yusuke; Nagao, Toshihiro; Watanabe, Yomi; Tominaga, Yoshio

    2002-11-01

    With the aim of developing a new cholesterol esterase for eliminating lipids on used contact lenses, microorganisms were screened for the enzyme activity. A Pseudomonas aeruginosa isolated from soil was found to produce a desirable enzyme. The enzyme had an isoelectric point of 3.2, and molecular mass of 58 kDa. The optimal temperature was around 53 degrees C at pH 7.0, and the optimal pH was from 5.5 to 9.5. The enzyme was stable between pH 5 and 10 for 19 h at 25 degrees C, and retained its activity up to 53 degrees C on 30 min of incubation at pH 7.0. The rates of hydrolysis of cholesteryl esters of different fatty acids were in the following order: linoleate > oleate > stearate > palmitate > caprylate > myristate > laurate, caprate > caproate > butyrate, acetate. Addition of (tauro)cholate to a final concentration of 100 mM markedly promoted the hydrolysis of triglycerides of short-, medium-, and long-chain fatty acids. When used with taurocholate, the enzyme acted as an effective cleaner for contact lenses stained with lipids consisting of cholesteryl oleate, tripalmitin, and stearyl stearate.

  12. Effect of non-toxic stabilizers on the gamma stabilization of poly(vinyl chloride) at sterilizing doses

    NASA Astrophysics Data System (ADS)

    Naimian, F.

    1999-05-01

    Gamma stabilization of PVC at sterilizing doses has been studied in the presence of various mixtures of non-toxic stabilizers. Plasticized PVC containing three different stabilizers like; calcium stearate, zinc stearate and epoxidized soya bean oil, were irradiated by 60-cobalt gamma ray at doses of 25-100 kGy and the effect of irradiation on the structural changes has been investigated up to 2 yr after irradiation. In the presence of this stabilizing system unstable allylic chlorine units were converted to stable allylic structures thus retarding the development of polyene sequences. This has been detected by the changes in UV absorbance at 290 nm. The changes of carbonyl index which has been studied by FTIR spectra, also shows the effectiveness of this stabilizing system up to 2 yr after irradiation. Measurements of Cl concentration has also confirmed the spectrophotometry results. Finally the most effective stabilizing system has been added to the Iranian PVC and its behaviour has been compared with the Solvay PVC for 6 months period after irradiation.

  13. Punch geometry and formulation considerations in reducing tablet friability and their effect on in vitro dissolution.

    PubMed

    Chowhan, Z T; Amaro, A A; Ong, J T

    1992-03-01

    The tablet friability resulting from formulation variations was studied under controlled granulation moisture content and tablet crushing strength. Tablets made with lactose were more friable than tablets made with microcrystalline cellulose. Replacement of 0.5% magnesium stearate with 0.5% stearic acid in the formula reduced tablet friability, whereas the combination of 0.5% stearic acid and up to 0.25% magnesium stearate did not increase tablet friability, decrease drug dissolution rate, or increase tablet-to-tablet variability in dissolution. Tablets compressed with extra deep concave punches resulted in lower friability compared with tablets compressed with standard concave or deep concave punches. The friabilities of the standard convex and deep convex tablets were similar, indicating that a critical level of punch tip curvature was important in reducing tablet friability. The dissolution rate was not affected by the punch tip geometry, but the tablet-to-tablet dissolution variability at the 0.5% stearic acid level for the extra deep convex tablets was higher compared with the standard convex tablets.

  14. Solid Layer Formation at Oil-Water Interfaces

    NASA Astrophysics Data System (ADS)

    de Ruiter, Rielle; Tjerkstra, Willem; Duits, Michel; Mugele, Frieder

    2011-11-01

    Metal stearates form at the interface between a decane solution of stearic acid (s.a.) and aqueous salt solutions of variable composition and pH. Studying the evolution of their mechanical, optical, and chemical properties as a function of time we find hardly any interfacial activity for pH pKa, s.a. deprotonates at the interface and forms metal stearates, eventually leading to the formation of macroscopic solid layers. Dynamic interfacial tension measurements reveal several stages of the process, including the subsequent formation of dilute and dense monolayers followed by three-dimensional growth. In the presence of divalent ions, the solid layers display a significant increase in the dilatational storage modulus. In the presence of multiple cation species (artificial seawater) the growth of the solid layers is particularly pronounced. The layers preferentially incorporate Ca2 ∖th as revealed by XPS and IR spectroscopy. Our results highlight in particular the importance of the synergistic effects of simultaneously present monovalent and divalent cation species on the interfacial adsorption.

  15. Spinnability and Characteristics of Polyvinylidene Fluoride (PVDF)-based Bicomponent Fibers with a Carbon Nanotube (CNT) Modified Polypropylene Core for Piezoelectric Applications

    PubMed Central

    Glauß, Benjamin; Steinmann, Wilhelm; Walter, Stephan; Beckers, Markus; Seide, Gunnar; Gries, Thomas; Roth, Georg

    2013-01-01

    This research explains the melt spinning of bicomponent fibers, consisting of a conductive polypropylene (PP) core and a piezoelectric sheath (polyvinylidene fluoride). Previously analyzed piezoelectric capabilities of polyvinylidene fluoride (PVDF) are to be exploited in sensor filaments. The PP compound contains a 10 wt % carbon nanotubes (CNTs) and 2 wt % sodium stearate (NaSt). The sodium stearate is added to lower the viscosity of the melt. The compound constitutes the fiber core that is conductive due to a percolation CNT network. The PVDF sheath’s piezoelectric effect is based on the formation of an all-trans conformation β phase, caused by draw-winding of the fibers. The core and sheath materials, as well as the bicomponent fibers, are characterized through different analytical methods. These include wide-angle X-ray diffraction (WAXD) to analyze crucial parameters for the development of a crystalline β phase. The distribution of CNTs in the polymer matrix, which affects the conductivity of the core, was investigated by transmission electron microscopy (TEM). Thermal characterization is carried out by conventional differential scanning calorimetry (DSC). Optical microscopy is used to determine the fibers’ diameter regularity (core and sheath). The materials’ viscosity is determined by rheometry. Eventually, an LCR tester is used to determine the core’s specific resistance. PMID:28811400

  16. Development of liposomal salbutamol sulfate dry powder inhaler formulation.

    PubMed

    Huang, Wen-Hua; Yang, Zhi-Jun; Wu, Heng; Wong, Yuen-Fan; Zhao, Zhong-Zhen; Liu, Liang

    2010-01-01

    The purpose of our study was to develop a formulation of liposomal salbutamol sulfate (SBS) dry powder inhaler (DPI) for the treatment of asthma. Liposomes of high encapsulation efficiency (more than 80%) were prepared by a vesicular phospholipid gel (VPG) technique. SBS VPG liposomes were subjected to lyophilization using different kinds of cryoprotectants in various mass ratios. Coarse lactose (63-106 microm) in different mass ratios was used as a carrier. Magnesium stearate (0.5%) was added as a lubricator. The dry liposomal powders were then crushed by ball milling and sieved through a 400-mesh sieve to control the mean particle size at about 10 microm. The effects of different kinds of cryoprotectants and the amount of lactose carrier on the fine particle fraction (FPF) of SBS were investigated. The results showed that the developed formulation of liposomal dry powder inhaler was obtained using lactose as a cryoprotectant with a mass ratio of lyophilized powder to carrier lactose at 1 : 5; 0.5% magnesium stearate was used as a lubricator. The value of FPF for SBS was 41.51+/-2.22% for this formulation. Sustained release of SBS from the VPG liposomes was found in the in vitro release study. The study results offer the promising possibility of localized pulmonary liposomal SBS delivery in the anhydrous state.

  17. Improving the hardness of dry granulated tablets containing sodium lauryl sulfate.

    PubMed

    Moore, Francis; Okelo, Geoffrey; Colón, Ivelisse; Kushner, Joseph

    2010-11-15

    The impact of the addition of a wetting agent, the surfactant sodium lauryl sulfate (SLS), on the tablet hardness of a dry granulated, solid oral dosage form was investigated. In three batches, SLS was added concurrently with: (1) a poorly soluble, highly hydrophobic active pharmaceutical ingredient (API) and the other excipients prior to the initial blending step, (2) magnesium stearate prior to roller compaction, or (3) magnesium stearate prior to tableting. A fourth batch, which did not contain SLS, served as a control. The maximum hardness of 100 mg, 1/4″-SRC tablets for the four batches--SLS added initially, prior to roller compaction, prior to tableting, and no SLS--were 61±3, 71±3, 89±5, and 86±3N, respectively, suggesting reduced processing of SLS improves tablet hardness by ∼50%. Dissolution of the tablets in 900 ml of simulated gastric fluid with paddles at 75 rpm showed that: (1) there was no impact on the insertion point of SLS into the process on API dissolution, and (2) that the presence of SLS improved dissolution by 5% compared to the control tablets. Adding SLS just prior to tableting can improve tablet hardness and yield similar dissolution performance relative to SLS addition prior to the initial blending step.

  18. Lack of activation of UCP1 in isolated brown adipose tissue mitochondria by glucose-O-ω-modified saturated fatty acids of various chain lengths.

    PubMed

    Breen, Eamon P; Pilgrim, Wayne; Clarke, Kieran J; Yssel, Cristy; Farrell, Mark; Zhou, Jian; Murphy, Paul V; Porter, Richard K

    2013-03-27

    We previously demonstrated that uncoupling protein 1 activity, as measured in isolated brown adipose tissue mitochondria (and as a native protein reconstituted into liposome membranes), was not activated by the non-flippable modified saturated fatty acid, glucose-O-ω-palmitate, whereas activity was stimulated by palmitate alone (40 nM free final concentration). In this study, we investigated whether fatty acid chain length had any bearing on the ability of glucose-O-ω-fatty acids to activate uncoupling protein 1. Glucose-O-ω-saturated fatty acids of various chain lengths were synthesized and tested for their potential to activate GDP-inhibited uncoupling protein 1-dependent oxygen consumption in brown adipose tissue mitochondria, and the results were compared with equivalent non-modified fatty acid controls. Here we demonstrate that laurate (12C), palmitate (16C) and stearate (18C) could activate GDP-inhibited uncoupling protein 1-dependent oxygen consumption in brown adipose tissue mitochondria, whereas there was no activation with glucose-O-ω-laurate (12C), glucose-O-ω-palmitate (16C), glucose-O-ω-stearate (18C), glucose-O-ω-arachidate (20C) or arachidate alone. We conclude that non-flippable fatty acids cannot activate uncoupling protein 1 irrespective of chain length. Our data further undermine the cofactor activation model of uncoupling protein 1 function but are compatible with the model that uncoupling protein 1 functions by flipping long-chain fatty acid anions.

  19. Influence of coating material on the flowability and dissolution of dry-coated fine ibuprofen powders.

    PubMed

    Qu, Li; Zhou, Qi Tony; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Morton, David A V

    2015-10-12

    This study investigates the effects of a variety of coating materials on the flowability and dissolution of dry-coated cohesive ibuprofen powders, with the ultimate aim to use these in oral dosage forms. A mechanofusion approach was employed to apply a 1% (w/w) dry coating onto ibuprofen powder with coating materials including magnesium stearate (MgSt), L-leucine, sodium stearyl fumarate (SSF) and silica-R972. No significant difference in particle size or shape was measured following mechanofusion with any material. Powder flow behaviours characterised by the Freeman FT4 system indicated coatings of MgSt, L-leucine and silica-R972 produced a notable surface modification and substantially improved flow compared to the unprocessed and SSF-mechanofused powders. ToF-SIMS provided a qualitative measure of coating extent, and indicated a near-complete layer on the drug particle surface after dry coating with MgSt or silica-R972. Of particular note, the dissolution rates of all mechanofused powders were enhanced even with a coating of a highly hydrophobic material such as magnesium stearate. This surprising increase in dissolution rate of the mechanofused powders was attributed to the lower cohesion and the reduced agglomeration after mechanical coating. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. The role of several l-HPCs in preventing tablet capping during direct compression of metronidazole.

    PubMed

    Martino, Piera Di; Malaj, Ledjan; Censi, Roberta; Martelli, Sante; Joiris, Etienne; Barthélémy, Christine

    2007-12-01

    Several low-hydroxypropyl cellulose (l-HPC) derivatives (LH-11, 21, 22, 31, and 32) differing in granulometric particle size or in hydroxypropyl content were considered in the present study. The l-HPC grades were characterized as pure powders, in order to determine both compression and densification behavior, in presence or in absence of magnesium stearate as lubricant, and then, were physically mixed in different proportions with metronidazole, which was also previously characterized as pure powder. The tabletability and compressibility of these binary mixtures were then evaluated, in presence or in absence magnesium stearate as lubricant at two different compression speeds (20 and 70 mm/sec). It was observed that both binary mixture compression behavior and capping tendency were influenced by compression speed and by the presence of lubricant. Differences in anti-capping efficiency between the l-HPCs may be related to their hydroxypropyl content. This parameter influences the interaction between the metronidazole and the polymer particles, and consequently the ability of the binary system to undergo densification under compression.

  1. The effects of erythromycin on theophylline elimination in normal males.

    PubMed

    May, D C; Jarboe, C H; Ellenburg, D T; Roe, E J; Karibo, J

    1982-01-01

    The effects of three erythromycin preparations on theophylline elimination kinetics were examined in 23 male subjects. Subjects received 6 mg/kg of the theophylline elixir orally and elimination kinetics were determined. The population was then randomized to receive either a lactose placebo, erythromycin base, erythromycin stearate, or erythromycin ethylsuccinate. Each 250-mg preparation was given four times a day for six days. On day seven, a repeat kinetic study was performed. The mean theophylline half-life of controls was 7.8 +/- 2.6 hours. The half-life increased significantly in all erythromycin treatment groups. The increase for the base, stearate, and ethylsuccinate groups was 51.7, 21.3, and 60.3 per cent, respectively. The total body theophylline clearance decreased significantly in all treatment groups. This was not associated with biochemical evidence of hepatitis. Three of four smokers who received erythromycin manifested no increase in theophylline half-life, in contrast to one of 13 nonsmokers. There was no difference in the percentage theophylline bound to serum protein for any of the erythromycin treatment groups or controls as determined by ultracentrifugation.

  2. Serum concentrations of vitamin D metabolites, vitamins A and E, and carotenoids in six canid and four ursid species at four zoos.

    PubMed

    Crissey, S; Ange, K; Slifka, K; Bowen, P; Stacewicz-Sapuntzakis, M; Langman, C; Sadler, W; Ward, A

    2001-01-01

    Nutritional status for six captive canid species (n=34) and four captive ursid species (n=18) were analyzed. The species analyzed included: African wild dog (Lycaon pictus), arctic fox (Alopex lagopus), gray wolf (Canis lupus), maned wolf (Chrysocyon brachyurus), Mexican wolf (Canis lupus baleiyi), red wolf (Canis rufus), brown bear (Ursus arctos), polar bear (Ursus maritimus), spectacled bear (Tremarctos ornatus), and sun bear (Ursus malayanus). Diet information was collected for these animals from each participating zoo (Brookfield Zoo, Fort Worth Zoo, Lincoln Park Zoological Gardens, and North Carolina Zoological Park). The nutritional composition of the diet for each species at each institution met probable dietary requirements. Blood samples were collected from each animal and analyzed for vitamin D metabolites 25(OH)D and 1,25(OH)(2)D, vitamin A (retinol, retinyl stearate, retinyl palmitate), vitamin E (alpha-tocopherol and gamma-tocopherol) and selected carotenoids. Family differences were found for 25(OH)D, retinol, retinyl stearate, retinyl palmitate and gamma-tocopherol. Species differences were found for all detectable measurements. Carotenoids were not detected in any species. The large number of animals contributing to these data, provides a substantial base for comparing the nutritional status of healthy animals and the differences among them.

  3. Design of covalently functionalized carbon nanotubes filled with metal oxide nanoparticles for imaging, therapy, and magnetic manipulation.

    PubMed

    Liu, Xiaojie; Marangon, Iris; Melinte, Georgian; Wilhelm, Claire; Ménard-Moyon, Cécilia; Pichon, Benoit P; Ersen, Ovidiu; Aubertin, Kelly; Baaziz, Walid; Pham-Huu, Cuong; Bégin-Colin, Sylvie; Bianco, Alberto; Gazeau, Florence; Bégin, Dominique

    2014-11-25

    Nanocomposites combining multiple functionalities in one single nano-object hold great promise for biomedical applications. In this work, carbon nanotubes (CNTs) were filled with ferrite nanoparticles (NPs) to develop the magnetic manipulation of the nanotubes and their theranostic applications. The challenges were both the filling of CNTs with a high amount of magnetic NPs and their functionalization to form biocompatible water suspensions. We propose here a filling process using CNTs as nanoreactors for high-yield in situ growth of ferrite NPs into the inner carbon cavity. At first, NPs were formed inside the nanotubes by thermal decomposition of an iron stearate precursor. A second filling step was then performed with iron or cobalt stearate precursors to enhance the encapsulation yield and block the formed NPs inside the tubes. Water suspensions were then obtained by addition of amino groups via the covalent functionalization of the external surface of the nanotubes. Microstructural and magnetic characterizations confirmed the confinement of NPs into the anisotropic structure of CNTs making them suitable for magnetic manipulations and MRI detection. Interactions of highly water-dispersible CNTs with tumor cells could be modulated by magnetic fields without toxicity, allowing control of their orientation within the cell and inducing submicron magnetic stirring. The magnetic properties were also used to quantify CNTs cellular uptake by measuring the cell magnetophoretic mobility. Finally, the photothermal ablation of tumor cells could be enhanced by magnetic stimulus, harnessing the hybrid properties of NP loaded-CNTs.

  4. Effect of particle size on compaction of materials with different deformation mechanisms with and without lubricants.

    PubMed

    Almaya, Ahmad; Aburub, Aktham

    2008-01-01

    This work investigates the effect of excipient particle size on compaction properties of brittle, plastic and viscoelastic materials with and without added lubricants. Sieve cuts of microcrystalline cellulose (MCC), starch and dibasic calcium phosphate dihydrate were obtained by sieving, then samples were tested without lubrication or with added lubricant (0.5% Mg stearate mixed for either 5 or 30-min). Compacts were left overnight before testing. It was found that in the absence of lubricant, compact tensile strength (TS) was dependent on particle size only for starch. With Mg stearate, lubricant sensitivity shows a strong dependence on excipient particle size for both starch and MCC, where smaller particles are less affected by lubricant. Dibasic calcium phosphate dihydrate was not sensitive to lubricant even after 30 min mixing. This study highlights that in the absence of lubricant, initial particle size of excipients has no impact on compact strength not only for dibasic calcium phosphate dihydrate (brittle), but also for MCC (plastic). On the other hand, TS is dependent on particle size both with or without added lubricant for starch (viscoelastic).

  5. Identification and antifungal activity of novel organic compounds found in cuticular and internal lipids of medically important flies.

    PubMed

    Gołębiowski, Marek; Cerkowniak, Magdalena; Urbanek, Aleksandra; Dawgul, Małgorzata; Kamysz, Wojciech; Boguś, Mieczysława I; Stepnowski, Piotr

    2015-01-01

    Novel organic compounds found in the cuticular and internal lipids of medically important flies were identified. Uracil, 9-tricosene, 1-oleoyl glycerol, dimethyl suberate and butyl stearate were tested for their potential antifungal activity. Minimal inhibitory concentrations of the compounds against reference strains of fungi were determined. Uracil and dimethyl suberate slightly inhibited the growth of entomopathogenic fungi. The cuticular and internal lipids of Calliphora vicina, Calliphora vomitoria, Sarcophaga carnaria and Musca domestica were studied by gas chromatography (GC) combined with mass spectrometry (GC/MS). A comparison of the lipid extracts between the preimaginal and mature stages showed adults flies contained a higher total content of the identified components. Furthermore, their amounts distinctly predominated in the internal lipids of all the species. The amount of 9-tricosene was the highest in adults of C. vicina, while the larvae and pupae had a definitively lower amount of this compound. Uracil was found to be the most abundant component in extracts obtained from C. vomitoria especially in the internal lipids of adults. 1-oleoyl glycerol was detected in all of the examined species of flies. It was most abundant in the internal extracts isolated from the larvae of C. vicina and the pupae of C. vomitoria. Suberic acid dimethyl ester was found in the larval and pupal internal lipids of C. vicina and S. carnaria in low amounts. Butyl stearate was identified only in the internal lipids of the larvae and adults of houseflies.

  6. Effect of Common Excipients on the Oral Drug Absorption of Biopharmaceutics Classification System Class 3 Drugs Cimetidine and Acyclovir.

    PubMed

    Vaithianathan, Soundarya; Haidar, Sam H; Zhang, Xinyuan; Jiang, Wenlei; Avon, Christopher; Dowling, Thomas C; Shao, Changxing; Kane, Maureen; Hoag, Stephen W; Flasar, Mark H; Ting, Tricia Y; Polli, James E

    2016-02-01

    The objective was to assess the impact of larger than conventional amounts of 14 commonly used excipients on Biopharmaceutics Classification System (BCS) class 3 drug absorption in humans. Cimetidine and acyclovir were used as model class 3 drugs across three separate four-way crossover bioequivalence (BE) studies (n = 24 each) in healthy human volunteers, denoted as study 1A, 1B, and 2. In study 1A and 1B, three capsule formulations of each drug were manufactured, collectively involving 14 common excipients. Capsule formulations that incorporated hydroxypropyl methylcellulose (HPMC) or magnesium stearate exhibited lower absorption. The cimetidine commercial solution contained sorbitol and also resulted in lower absorption. Hence, in study 2, two capsule formulations with lower amounts of HPMC and magnesium stearate, the sorbitol-containing commercial solution, and a sorbitol-free solution were assessed for BE. Overall, 12 common excipients were found in large amounts to not impact BCS class 3 drug absorption in humans, such that these excipients need not be qualitatively the same nor quantitatively very similar to reference, but rather simply be not more than the quantities studied here. Meanwhile, for each HPMC and microcrystalline cellulose, BCS class 3 biowaivers require these two excipients to be qualitatively the same and quantitatively very similar to the reference.

  7. Serum concentrations of lipids, vitamin d metabolites, retinol, retinyl esters, tocopherols and selected carotenoids in twelve captive wild felid species at four zoos.

    PubMed

    Crissey, Susan D; Ange, Kimberly D; Jacobsen, Krista L; Slifka, Kerri A; Bowen, Phyllis E; Stacewicz-Sapuntzakis, Maria; Langman, Craig B; Sadler, William; Kahn, Stephen; Ward, Ann

    2003-01-01

    Serum concentrations of several nutrients were measured in 12 captive wild felid species including caracal (Felis caracal), cheetah (Acinonyx jubatus), cougar (Felis concolor), fishing cat (Felis viverrinus), leopard (Panthera pardus), lion (Panthera leo), ocelot (Felis pardalis), pallas cat (Felis manul), sand cat (Felis margarita), serval (Felis serval), snow leopard (Panthera uncia) and tiger (Panthera tigris). Diet information was collected for these animals from each participating zoo (Brookfield Zoo, Fort Worth Zoo, Lincoln Park Zoological Gardens and North Carolina Zoological Park). The nutritional composition of the diets at each institution met the probable dietary requirements for each species except for the pallas cat. Blood samples were collected from each animal (n = 69) and analyzed for lipids (total cholesterol, triacylglycerides, HDL cholesterol and LDL cholesterol), vitamin D metabolites [25-hydroxycholecalciferol (25(OH)D) and 1,25-dihydroxycholecalciferol (1,25(OH)(2)D)], vitamin A (retinol, retinyl stearate and retinyl palmitate), vitamin E (alpha- and gamma-tocopherol) and selected carotenoids. Species differences were found for all except triacylglycerides and 1,25(OH)(2)D. Genus differences were found for retinol, retinyl palmitate, retinyl stearate, gamma-tocopherol and beta-carotene. Circulating nutrient concentrations for many of the species in this study have not been reported previously and most have not been compared with the animals' dietary intakes. The large number of animals analyzed provides a substantial base for comparing the serum nutrient concentrations of healthy animals, for both wild and captive exotic species.

  8. Effects of disintegration-promoting agent, lubricants and moisture treatment on optimized fast disintegrating tablets.

    PubMed

    Late, Sameer G; Yu, Yi-Ying; Banga, Ajay K

    2009-01-05

    Effects of calcium silicate (disintegration-promoting agent) and various lubricants on an optimized beta-cyclodextrin-based fast-disintegrating tablet formulation were investigated. Effects of moisture treatment were also evaluated at 75, 85 and 95% relative humidities. A two factor, three levels (3(2)) full factorial design was used to optimize concentrations of calcium silicate and lubricant. Magnesium stearate, being commonly used lubricant, was used to optimize lubricant concentration in optimization study. Other lubricants were evaluated at an obtained optimum concentration. Desiccator with saturated salt solutions was used to analyze effects of moisture treatments. Results of multiple linear regression analysis revealed that concentration of calcium silicate had no effect; however concentration of lubricant was found to be important for tablet disintegration and hardness. An optimized value of 1.5% of magnesium stearate gave disintegration time of 23.4 s and hardness of 1.42 kg. At an optimized concentration, glycerol dibehenate and L-leucine significantly affected disintegration time, while talc and stearic acid had no significant effect. Tablet hardness was significantly affected with L-leucine, while other lubricants had no significant effect. Hardness was not affected at 75% moisture treatment. Moisture treatment at 85 and 95% increased hardness of the tablets; however at the same time it negatively affected the disintegration time.

  9. A study of degradation resistance and cytocompatibility of super-hydrophobic coating on magnesium.

    PubMed

    Zhang, Yufen; Feyerabend, Frank; Tang, Shawei; Hu, Jin; Lu, Xiaopeng; Blawert, Carsten; Lin, Tiegui

    2017-09-01

    Calcium stearate based super-hydrophobic coating was deposited on plasma electrolytic oxidation (PEO) pre-treated magnesium substrate. The pre-treated magnesium and super-hydrophobic coating covered sample were characterized by scanning electron microscopy, X-ray diffraction and electrochemical corrosion measurements. The cytocompatibility and degradation resistance of magnesium, pre-treated magnesium and super-hydrophobic coating were analysed in terms of cell adhesion and osteoblast differentiation. The results indicate that the calcium stearate top coating shows super-hydrophobicity and that the surface is composed of micro/nanostructure. The super-hydrophobic coating covered sample shows higher barrier properties compared with the PEO pre-treated magnesium and bare magnesium. Human osteoblast proliferation, but not differentiation is enhanced by the PEO coating. Contrary, the super-hydrophobic coating reduces proliferation, but enhances differentiation of osteoblast, observable by the formation of hydroxyapatite. The combination of corrosion protection and cell reaction indicates that this system could be interesting for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Spinnability and Characteristics of Polyvinylidene Fluoride (PVDF)-based Bicomponent Fibers with a Carbon Nanotube (CNT) Modified Polypropylene Core for Piezoelectric Applications.

    PubMed

    Glauß, Benjamin; Steinmann, Wilhelm; Walter, Stephan; Beckers, Markus; Seide, Gunnar; Gries, Thomas; Roth, Georg

    2013-07-03

    This research explains the melt spinning of bicomponent fibers, consisting of a conductive polypropylene (PP) core and a piezoelectric sheath (polyvinylidene fluoride). Previously analyzed piezoelectric capabilities of polyvinylidene fluoride (PVDF) are to be exploited in sensor filaments. The PP compound contains a 10 wt % carbon nanotubes (CNTs) and 2 wt % sodium stearate (NaSt). The sodium stearate is added to lower the viscosity of the melt. The compound constitutes the fiber core that is conductive due to a percolation CNT network. The PVDF sheath's piezoelectric effect is based on the formation of an all-trans conformation β phase, caused by draw-winding of the fibers. The core and sheath materials, as well as the bicomponent fibers, are characterized through different analytical methods. These include wide-angle X-ray diffraction (WAXD) to analyze crucial parameters for the development of a crystalline β phase. The distribution of CNTs in the polymer matrix, which affects the conductivity of the core, was investigated by transmission electron microscopy (TEM). Thermal characterization is carried out by conventional differential scanning calorimetry (DSC). Optical microscopy is used to determine the fibers' diameter regularity (core and sheath). The materials' viscosity is determined by rheometry. Eventually, an LCR tester is used to determine the core's specific resistance.

  11. Effects of automated external lubrication on tablet properties and the stability of eprazinone hydrochloride.

    PubMed

    Yamamura, Takahiro; Ohta, Tomoaki; Taira, Toshinari; Ogawa, Yutaka; Sakai, Yasuyuki; Moribe, Kunikazu; Yamamoto, Keiji

    2009-03-31

    We investigated the advantages of an external lubrication technique for tableting. A newly developed external lubricating system was applied to tableting in a rotary tablet press using magnesium stearate. The resulting tablets were compared with tablets produced by the conventional internal lubrication method, in which lubricant is blended before tableting. As a model API, we chose eprazinone hydrochloride, because it is easily hydrolyzed by alkaline lubricant. The amount of lubricant required to prevent sticking with external lubrication was only 1/13th of that required with internal lubrication. External lubrication increased tablet crushing strength by 40%, without prolonging tablet disintegration time, and improved the residual ratio of eprazinone hydrochloride in tablets stored under stress conditions for 4 weeks by 10%. The distribution of lubricant on the surface of externally lubricated tablets was observed by scanning electron microscopy after the preparation by focused ion beam milling. The lubricant had formed a layer on the tablet surface. At the central part of the tablet surface, this layer was much thinner than at the edges, and remained extremely thin even when there was excess magnesium stearate. This is the first report to describe the distribution of lubricant on the surface of externally lubricated tablets.

  12. Formulation, characterization and evaluation of the effect of polymer concentration on the release behavior of insulin-loaded Eudragit®-entrapped mucoadhesive microspheres

    PubMed Central

    Kenechukwu, Franklin C.; Momoh, Mumuni A.

    2016-01-01

    Introduction: The aim of this study was to use Eudragit® RL 100 (pH-independent polymer) and magnesium stearate (a hydrophobic droplet stabilizer) in combination to improve the controlled release effect of insulin-loaded Eudragit® entrapped microspheres prepared by the emulsification-coacervation technique. Materials and Methods: Mucoadhesive insulin-loaded microspheres containing magnesium stearate and varying proportions of Eudragit® RL 100 were prepared by the emulsification-coacervation technique and evaluated for thermal properties, physicochemical performance, and in vitro dissolution in acidic and subsequently basic media. Results: Stable, spherical, brownish, discrete, free-flowing and mucoadhesive insulin-loaded microspheres with size range of 14.20 ± 0.30-19.80 ± 0.60 μm and loading efficiency of 74.55 ± 1.05-75.90 ± 1.94% were formed. After 3 h, microspheres prepared with insulin: Eudragit® RL 100 ratios of 1:4, 1:6, and 1:8 released 73.40 ± 1.38, 66.20 ± 1.59, and 71.30 ± 1.27 (%) of insulin, respectively. Conclusion: The physicochemical and physico-technical properties of the microspheres developed in this study demonstrated the effectiveness of the Eudragit® RL entrapped mucoadhesive microspheres (prepared by the emulsification-coacervation technique using varying polymer concentration) as a carrier system for oral insulin delivery. PMID:27051626

  13. Formation of mannitol core microparticles for sustained release with lipid coating in a mini fluid bed system.

    PubMed

    Wang, Bifeng; Friess, Wolfgang

    2017-09-08

    The goal of this study was to prepare sustained release microparticles for methyl blue and aspartame as sparingly and freely water-soluble model drugs by lipid film coating in a Mini-Glatt fluid bed, and to assess the effect of coating load of two of lipids, hard fat and glyceryl stearate, on the release rates. 30g drug-loaded mannitol carrier microparticles with average diameter of 500 or 300μm were coated with 5g, 10g, 20g and 30g lipids, respectively. The model drugs were completely released in vitro through pores which mainly resulted from dissolution of the polyol core beads. The release of methyl blue from microparticles based on 500μm carrier beads extended up to 25days, while aspartame release from microparticles formed from 300μm carrier beads was extended to 7days. Although glyceryl stearate exhibits higher wettability, burst and release rates were similar for the two lipid materials. Polymorphic transformation of the hart fat was observed upon release. The lipid-coated microparticles produced with 500μm carrier beads showed slightly lower burst release compared to the microparticles produced with 300μm carrier beads as they carried relatively thicker lipid layer based on an equivalent lipid to mannitol ratio. Aspartame microparticles showed a much faster release than methyl blue due to the higher water-solubility of aspartame. Copyright © 2017. Published by Elsevier B.V.

  14. Fabrication of superhydrophobic sol-gel composite films using hydrophobically modified colloidal zinc hydroxide.

    PubMed

    Lakshmi, R V; Basu, Bharathibai J

    2009-11-15

    A superhydrophobic sol-gel composite film was fabricated by incorporating hydrophobically modified colloidal zinc hydroxide (CZH) in sol-gel matrix. CZH was prepared by controlled precipitation and modified by treatment with stearic acid. The concentration of stearic acid and stirring time were optimized to obtain modified CZH with very high water contact angle (WCA) of 165 degrees and sliding angle (SA)<2 degrees . X-ray diffraction (XRD) analysis has shown that the crystal structure of CZH was mainly composed of epsilon-zinc hydroxide and the modified CZH indicated the presence of zinc stearate. The modified CZH film exhibited a microstructure which resembled clusters of interconnected rods creating roughness on the film surface. The modified CZH suspension was dispersed in an acid-catalyzed sol of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS) and spray-coated on glass slides to prepare sol-gel composite coatings. The concentration of CZH in the composite film was optimized to obtain superhydrophobic surfaces. FTIR spectrum also confirmed the presence of zinc stearate in the composite film. The method is simple and cost-effective and does not involve any expensive chemicals or equipments.

  15. Fatty acid esters produced by Lasiodiplodia theobromae function as growth regulators in tobacco seedlings.

    PubMed

    Uranga, Carla C; Beld, Joris; Mrse, Anthony; Córdova-Guerrero, Iván; Burkart, Michael D; Hernández-Martínez, Rufina

    2016-04-01

    The Botryosphaeriaceae are a family of trunk disease fungi that cause dieback and death of various plant hosts. This work sought to characterize fatty acid derivatives in a highly virulent member of this family, Lasiodiplodia theobromae. Nuclear magnetic resonance and gas chromatography-mass spectrometry of an isolated compound revealed (Z, Z)-9,12-ethyl octadecadienoate, (trivial name ethyl linoleate), as one of the most abundant fatty acid esters produced by L. theobromae. A variety of naturally produced esters of fatty acids were identified in Botryosphaeriaceae. In comparison, the production of fatty acid esters in the soil-borne tomato pathogen Fusarium oxysporum, and the non-phytopathogenic fungus Trichoderma asperellum was found to be limited. Ethyl linoleate, ethyl hexadecanoate (trivial name ethyl palmitate), and ethyl octadecanoate, (trivial name ethyl stearate), significantly inhibited tobacco seed germination and altered seedling leaf growth patterns and morphology at the highest concentration (0.2 mg/mL) tested, while ethyl linoleate and ethyl stearate significantly enhanced growth at low concentrations, with both still inducing growth at 98 ng/mL. This work provides new insights into the role of naturally esterified fatty acids from L. theobromae as plant growth regulators with similar activity to the well-known plant growth regulator gibberellic acid. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Effect of Span 60 on the Microstructure, Crystallization Kinetics, and Mechanical Properties of Stearic Acid Oleogels: An In-Depth Analysis.

    PubMed

    Uvanesh, K; Sagiri, S S; Senthilguru, K; Pramanik, K; Banerjee, I; Anis, Arfat; Al-Zahrani, S M; Pal, Kunal

    2016-02-01

    Modulation of crystallization of stearic acid and its derivatives is important for tuning the properties of stearate oleogels. The present study delineates the crystallization of stearic acid in stearate oleogels in the presence of Span 60. Microarchitecture analysis revealed that stearic acid crystals in the oleogels changed its shape from plate-like structure to a branched architecture in the presence of Span 60. Consequently, a significant variation in the mobility of the solute molecules inside the oleogel (Fluorescence recovery after photobleaching studies, FRAP analysis) was observed. Thermal analysis (gelation kinetics and DSC) revealed shortening of nucleation induction time and secondary crystallization with an increase in the Span 60 concentration. Furthermore, isosolid diagram suggested better physical stability of the formulations at higher proportions of Span 60. XRD analysis indicated that there was a decrease in the crystal size and the crystallinity of the stearic acid crystals with an increase in Span 60 concentration in the Span 60 containing oleogels. However, crystal growth orientation was unidirectional and found unaltered with Span 60 concentration (Avarmi analysis using DSC data). The mechanical study indicated a composition-dependent variation in the viscoelastic properties (instantaneous [τ1 ], intermediate [τ2 ], and delayed [τ3 ] relaxation times) of the formulations. In conclusion, Span 60 can be used to alter the kinetics of the crystallization, crystal habit and crystal structure of stearic acid. This study provides a number of clues that could be used further for developing oleogel based formulation. © 2015 Institute of Food Technologists®

  17. Lubricant-Induced Crystallization of Itraconazole From Tablets Made of Electrospun Amorphous Solid Dispersion.

    PubMed

    Démuth, Balázs; Farkas, Attila; Balogh, Attila; Bartosiewicz, Karolina; Kállai-Szabó, Barnabás; Bertels, Johny; Vigh, Tamás; Mensch, Jurgen; Verreck, Geert; Van Assche, Ivo; Marosi, György; Nagy, Zsombor K

    2016-09-01

    Investigation of downstream processing of nanofibrous amorphous solid dispersions to generate tablet formulation is in a quite early phase. Development of high speed electrospinning opened up the possibility to study tableting of electrospun solid dispersions (containing polyvinylpyrrolidone-vinyl acetate and itraconazole [ITR] in this case). This work was conducted to investigate the influence of excipients on dissolution properties and the feasibility of scaled-up rotary press tableting. The dissolution rates from tablets proved to be mainly composition dependent. Magnesium stearate acted as a nucleation promoting agent (providing an active hydrophobic environment for crystallization of ITR) hindering the total dissolution of ITR. This crystallization process proved to be temperature dependent as well. However, the extent of dissolution of more than 95% was realizable when a less hydrophobic lubricant, sodium stearyl fumarate (soluble in the medium), was applied. Magnesium stearate induced crystallization even if it was put in the dissolution medium next to proper tablets. After optimization of the composition, scaled-up tableting on a rotary press was carried out. Appropriate dissolution of ITR from tablets was maintained for 3 months at 25°C/60% relative humidity. HPLC measurements confirmed that ITR was chemically stable both in the course of downstream processing and storage.

  18. Diffusion, molecular separation, and drug delivery from lipid mesophases with tunable water channels.

    PubMed

    Negrini, Renata; Mezzenga, Raffaele

    2012-11-27

    Lyotropic liquid crystals characterized by a bicontinuous cubic phase (BCP) have a structure characterized by interpenetrated water channels following triply periodic minimal surfaces, which can be stable in excess water conditions and thus suitable in a multitude of applications. The control of the water channels size in these systems has a direct impact on their use for drug delivery, crystallization, and membrane separation processes. In this work we carry out systematic diffusion studies to show how the control on the water channel dimensions directly correlates with the release and separation performance of bicontinuous cubic phases. Specifically, we tune the water channels diameter of the monolinolein/water system by adding different amounts of sucrose stearate, which, having hydration-enhancing properties, can shift the boundaries of the phase diagram. We then design a model bicontinuous cubic phase lipidic membrane of the Im3m space group, having a sugar ester to monolinolein ratio of 20%, and we follow the diffusion within its water channels, by using molecules that differ systematically in size and molecular conformation, and we demonstrate, for each class of molecules, a diffusion-enhanced process upon increase of the water channel diameter. Finally, we also show the ability of the bicontinuous cubic phase to efficiently and selectively separate nanoparticles of a target size, by choosing an amount of sucrose stearate for which the water channel diameter and the nanoparticle dimensions match, demonstrating the possible use of these systems as filtering membranes of tunable molecular cutoff.

  19. Differences in hydrolytic abilities of two crude lipases from Geotrichum candidum 4013.

    PubMed

    Brabcová, Jana; Zarevúcka, Marie; Macková, Martina

    2010-12-01

    The fungus Geotrichum candidum 4013 produces two types of lipases (extracellular and cell-bound). Both enzymes were tested for their hydrolytic ability to p-nitrophenyl esters and compounds having a structure similar to the original substrate (triacylglycerols). Higher lipolytic activity of extracellular lipase was observed when triacylglycerols of medium- (C12) and long- (C18) chain fatty acids were used as substrates. Cell-bound lipase preferentially hydrolysed trimyristate (C14). The differences in the abilities of these two enzymes to hydrolyse p-nitrophenyl esters were observed as well. The order of extracellular lipase hydrolysis relation velocity was as follows: p-nitrophenyl decanoate > p-nitrophenyl caprylate > p-nitrophenyl laurate > p-nitrophenyl palmitate > p-nitrophenyl stearate. The cell-bound lipase indicates preference for p-nitrophenyl palmitate. The most striking differences in the ratios between the activity of both lipases (extracellular : cell-bound) towards different fatty acid methyl esters were 2.2 towards methyl hexanoate and 0.46 towards methyl stearate (C18). The Michaelis constant (K(m) ) and maximum reaction rate (V(max) ) for p-nitrophenyl palmitate hydrolysis of cell-bound lipase were significantly higher (K(m) 2.462 mM and V(max) 0.210 U/g/min) than those of extracellular lipase (K(m) 0.406 mM and V(max) 0.006 U/g/min).

  20. Investigating critical effects of variegated lubricants, glidants and hydrophilic additives on lag time of press coated ethylcellulose tablets.

    PubMed

    Patadia, Riddhish; Vora, Chintan; Mittal, Karan; Mashru, Rajashree

    2016-01-01

    The research envisaged focuses on vital impacts of variegated lubricants, glidants and hydrophilic additives on lag time of press coated ethylcellulose (EC) tablets using prednisone as a model drug. Several lubricants and glidants such as magnesium stearate, colloidal SiO2, sodium stearyl fumarate, talc, stearic acid, polyethylene glycol (6000) and glyceryl behenate were investigated to understand their effects on lag time by changing their concentrations in outer coat. Further, the effects of hydrophilic additives on lag time were examined for hydroxypropylmethylcellulose (E5), hydroxypropylcellulose (EF and SSL), povidone (K30), copovidone, polyethylene glycol (4000), lactose and mannitol. In vitro drug release testing revealed that each selected lubricant/glidant, if present even at concentration of 0.25% w/w, significantly reduced the lag time of press coated tablets. Specifically, colloidal SiO2 and/or magnesium stearate were detrimental while other lubricants/glidants were relatively less injurious. Among hydrophilic additives, freely water soluble fillers had utmost influence in lag time, whereas, comparatively less impact was observed with polymeric binders. Concisely, glidant and lubricant should be chosen to have minimal impact on lag time and further judicious selection of hydrophilic additives should be exercised for modulating lag time of pulsatile release formulations.

  1. The adjuvant activity of fatty acid esters. The role of acyl chain length and degree of saturation.

    PubMed Central

    Bomford, R

    1981-01-01

    Water-in-oil emulsions of metabolizable fatty acid esters, with the non-toxic surfactant Pluronic L122 as emulsifying agent, potentiated the humoral response to bovine serum albumin and staphylococcal toxoid in the mouse. Adjuvant activity was increased by changing the chemical nature of the esters as follows: (i) using a series of ethyl esters, adjuvant activity appeared when the acyl chain length of the fatty acid component was 16 or greater; (ii) isobutyl and isopropyl esters of palmitic acid (C16:0) were superior to ethyl; (iii) the ethyl esters of oleic (C18:1) and linoleic (C18:2) acids were better than stearic (C18:0). Since emulsions prepared with longer chain saturated esters are very viscous or solid at room temperature, and unsaturated esters are chemically reactive, emulsions were prepared with differing proportions of ethyl caprate (C10:0) and butyl stearate. At a ratio of 9:1 the emulsions possessed the low viscosity of ethyl caprate, but gained the adjuvant activity of butyl stearate. 125I-labelled BSA was retained in the footpad to a significantly greater extent than with a caprate emulsion, but reasons are given for believing that slow release of antigen is not the only mechanism of adjuvant activity. The ester emulsions caused more acute but less chronic local inflammation (footpad swelling) than Freund's incomplete adjuvant. PMID:7275184

  2. Novel Method to Prepare Magnesium by Aluminothermic Reduction of Magnesia and Calcium Hydroxide at Normal Atmosphere, 1223 K (950 °C)

    NASA Astrophysics Data System (ADS)

    Zhang, Teng; Du, Shuang-Ming; Sun, Wan-Chang; Zhang, Ju-Mei; Niu, Li-Bin; Zheng, Bin; Hua, Xiao-Hu

    2017-02-01

    An experimental apparatus was designed to investigate the aluminothermic reduction of the mixture of MgO and Ca(OH)2 at normal atmosphere, 1223 K (950 °C), with the molar ratio of MgO:Al:Ca(OH)2 to be 3:2:1, reinforced by high-energy ball milling. The effect of mechanical milling time and content of grinding aid (sodium stearate) on the reduction ratio of MgO were studied. Moreover, the reduzate and reactant activated by ball milling were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectrometer analysis. The average grain sizes of Al and MgO activated by ball milling were also calculated by Scherrer formula. The results indicate that the reduction ratio of MgO is increased with increasing mechanical milling time and content of sodium stearate. The high-energy ball milling has good reinforcement on the aluminothermic reduction of MgO. Moreover, the strengthening mechanism of mechanical force on the reaction was further discussed.

  3. An evaluation of acute hydrogen sulfide poisoning in rats through serum metabolomics based on gas chromatography-mass spectrometry.

    PubMed

    Zhang, Meiling; Deng, Mingjie; Ma, Jianshe; Wang, Xianqin

    2014-01-01

    Hydrogen sulfide (H2S) is the second leading cause of toxin-related deaths in the operational site. Its main target organs of toxic effects are the central nervous system and respiratory system. In this study, we developed a serum metabonomic method, based on gas chromatography-mass spectrometry (GC/MS), to evaluate the effect of acute poisoning by hydrogen sulfide on rats. Pattern recognition analysis, including both principal component analysis (PCA) and partial least squares-discriminate analysis (PLS-DA), revealed that acute hydrogen sulfide poisoning induced metabolic perturbations. Compared to the control group, the level of urea, glucose, glyceryl stearate in rat serum of the poisoning group increased after two hours, and the level of glucose, docosahexaenoic acid, glyceryl stearate and arachidonic acid in rat serum of the poisoning group increased after 48 h, while the L-valine, galactose, L-tyrosine levels decreased. Our results indicate that metabonomic methods based on GC/MS may be useful to elucidate acute hydrogen sulfide poisoning through the exploration of biomarkers.

  4. Unexpected skin barrier influence from nonionic emulsifiers.

    PubMed

    Bárány, E; Lindberg, M; Lodén, M

    2000-02-15

    Skin disorders are often treated with creams containing various active substances. The creams also contain emulsifiers, which are surface-active ingredients used to stabilize the emulsion. Emulsifiers are potential irritants and in the present study the influence of stearic acid, glyceryl stearate, PEG-2, -9, -40, and -100 stearate, steareth-2, -10 and -21 on normal as well as on irritated skin have been evaluated with non-invasive measurements. Test emulsions were created by incorporating 5% emulsifiers in a water/mineral oil mixture (50:50). The emulsions and their vehicle were then applied to normal skin for 48 h and to sodium lauryl sulfate (SLS) damaged skin for 17 h in aluminum chambers. Twenty-four hours after removal of the chambers the test sites were evaluated for degree of irritation. In normal skin, the emulsifiers induced significant differences in TEWL but not in skin blood flow. Five of the emulsifiers increased TEWL. In SLS-damaged skin an aggravation of the irritation was expected. However, no differences regarding skin blood flow was noted from the emulsifiers. Furthermore, three emulsifiers unexpectedly decreased TEWL. These results highlight the possibility of absorption of these emulsifiers into the lipid bilayer, which increase TEWL in normal skin and decrease TEWL in damaged skin.

  5. Effect of particle shape on powder flowability of microcrystalline cellulose as determined using the vibration shear tube method.

    PubMed

    Horio, Takehiko; Yasuda, Masatoshi; Matsusaka, Shuji

    2014-10-01

    Powder flowability of microcrystalline cellulose particles having different particle shapes, whose aspect ratios ranged from 1.8 to 6.4, was measured using the vibration shear tube method. Particles lubricated with magnesium stearate were also investigated in order to evaluate the effect of surface modification on powder flowability. Particles were discharged through a narrow gap between a vibrating tube edge and a flat bottom surface, where each particle experienced high shear forces, thus, overcoming adhesion and friction forces. Vibration amplitude was increased at a constant rate during measurement and the masses of the discharged particles were measured at consistent time intervals. Flowability profiles, i.e., the relationships between the mass flow rates of the discharged particles and their vibration accelerations, were obtained from these measurements. Critical vibration accelerations and characteristic mass flow rates were then determined from flowability profiles in order to evaluate static and dynamic friction properties. The results were compared with those obtained using conventional methods. It was found that angle of repose and compressibility were related to static and dynamic friction properties. Furthermore, it was found that particle aspect ratio more significantly affects powder flowability than does lubrication with magnesium stearate.

  6. Catalyst-free bottom-up growth of graphene nanofeatures along with molecular templates on dielectric substrates.

    PubMed

    Min, Misook; Seo, Sohyeon; Yoon, Yeoheung; Cho, Kyungjune; Lee, Sae Mi; Lee, Takhee; Lee, Hyoyoung

    2016-09-29

    Synthesis of graphene nanostructures has been investigated to provide outstanding properties for various applications. Herein, we report molecular thin film-assisted growth of graphene into nanofeatures such as nanoribbons and nanoporous sheets along with a predetermined molecular orientation on dielectric substrates without metal catalysts. A Langmuir-Blodgett (LB) method was used for the formation of the molecularly patterned SiO2 substrates with ferric stearate layers, which acted as a template for the directional growth of the polypyrrole graphene precursor. The nanofeatures of the graphene were determined by the number of ferric stearate layers (e.g., nanoribbons from multiple layers and nanoporous sheets from a single layer). The graphene nanoribbons (GNRs) containing pyrrolic N enriched edges exhibited a p-type semiconducting behavior, whereas the nanoporous graphene sheets containing inhomogeneous pores and graphitic N enriched basal planes exhibited the typical electronic transport of nitrogen-doped graphene. Our approaches provide two central methods for graphene synthesis such as bottom-up and direct processes for the future development of graphene nanoelectronics.

  7. Cobalt nanowires prepared by heterogeneous nucleation in propanediol and their catalytic properties

    NASA Astrophysics Data System (ADS)

    Liu, Qiying; Guo, Xiaohui; Chen, Junli; Li, Juan; Song, Wei; Shen, Wenjie

    2008-09-01

    Co nanowires with a diameter of 10 nm and a length up to 1000 nm were synthesized by the chemical reduction of cobalt acetate in propanediol using Ru as the heterogeneous agent and stearic acid as the surfactant. The morphology of the Co nanomaterials depended strongly on the concentrations of stearic acid and sodium hydroxide and the temperature, which governed the reduction rate of Co2+ in the liquid and the growth rate of Co nanocrystals. Very tiny Ru nanoparticles formed at the beginning of the synthesis significantly lowered the reduction temperature of Co2+ species, affording an easy separation and growth of Co nanocrystals. Solid cobalt stearate and cobalt alkoxide were readily formed at the initial stage of the synthesis, which determined the reduction rate of Co2+ through a dynamic equilibrium between the solid and the solution. In addition to forming cobalt stearate, the stearic acid, as a structure-directing agent, mainly induced the anisotropic growth of Co nanocrystals. The Co nanowires as heterogeneous catalysts showed quite promising activity and selectivity for the hydrogenation of citral and the hydrogenolysis of glycerol.

  8. Compatibility study between ketoprofen and pharmaceutical excipients used in solid dosage forms.

    PubMed

    Tiţa, Bogdan; Fuliaş, Adriana; Bandur, Geza; Marian, Eleonora; Tiţa, Dumitru

    2011-09-10

    Thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) techniques were used for assessing the compatibility between ketoprofen (KT) and several excipients as: corn starch, microcrystalline cellulose (PH 101 and PH 102), colloidal silicon dioxide, lactose (monohydrate and anhydre), polyvinylpyrrolidone K30, magnesium stearate and talc, commonly used in the pharmaceutical form. In order to investigate the possible interactions between the components, the thermal curves of KT and each selected excipients were compared with those of their 1:1 (w/w) physical mixtures. For KT, the DSC curves have shown a sharp endothermic peak at 96.8 °C which corresponds to the melting process (literature value: 94-97 °C), respectively the TG curves demonstrated a simple stage of mass loss in the temperature range of 235-400 °C. FT-IR spectroscopy and X-ray powder diffraction (XRPD) were used as complementary techniques to adequately implement and assist in interpretation of the DSC results. On the basis of thermal results, a possible interaction was found between the KT with polyvinylpyrrolidone K30 and magnesium stearate, which could influence the stability of the KT in the binary mixtures. These possible incompatibilities were confirmed by FT-IR and X-ray analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. TRPV4 in porcine lens epithelium regulates hemichannel-mediated ATP release and Na-K-ATPase activity.

    PubMed

    Shahidullah, Mohammad; Mandal, Amritlal; Delamere, Nicholas A

    2012-06-15

    In several tissues, transient receptor potential vanilloid 4 (TRPV4) channels are involved in the response to hyposmotic challenge. Here we report TRPV4 protein in porcine lens epithelium and show that TRPV4 activation is an important step in the response of the lens to hyposmotic stress. Hyposmotic solution (200 mosM) elicited ATP release from intact lenses and TRPV4 antagonists HC 067047 and RN 1734 prevented the release. In isosmotic solution, the TRPV4 agonist GSK1016790A (GSK) elicited ATP release. When propidium iodide (PI) (MW 668) was present in the bathing medium, GSK and hyposmotic solution both increased PI entry into the epithelium of intact lenses. Increased PI uptake and ATP release in response to GSK and hyposmotic solution were abolished by a mixture of agents that block connexin and pannexin hemichannels, 18α-glycyrrhetinic acid and probenecid. Increased Na-K-ATPase activity occurred in the epithelium of lenses exposed to GSK and 18α-glycyrrhetinic acid + probenecid prevented the response. Hyposmotic solution caused activation of Src family kinase and increased Na-K-ATPase activity in the lens epithelium and TRPV4 antagonists prevented the response. Ionomycin, which is known to increase cytoplasmic calcium, elicited ATP release, the magnitude of which was no greater when lenses were exposed simultaneously to ionomycin and hyposmotic solution. Ionomycin-induced ATP release was significantly reduced in calcium-free medium. TRPV4-mediated calcium entry was examined in Fura-2-loaded cultured lens epithelium. Hyposmotic solution and GSK both increased cytoplasmic calcium that was prevented by TRPV4 antagonists. The cytoplasmic calcium rise in response to hyposmotic solution or GSK was abolished when calcium was removed from the bathing solution. The findings are consistent with hyposmotic shock-induced TRPV4 channel activation which triggers hemichannel-mediated ATP release. The results point to TRPV4-mediated calcium entry that causes a cytoplasmic

  10. TRPV4 in porcine lens epithelium regulates hemichannel-mediated ATP release and Na-K-ATPase activity

    PubMed Central

    Mandal, Amritlal; Delamere, Nicholas A.

    2012-01-01

    In several tissues, transient receptor potential vanilloid 4 (TRPV4) channels are involved in the response to hyposmotic challenge. Here we report TRPV4 protein in porcine lens epithelium and show that TRPV4 activation is an important step in the response of the lens to hyposmotic stress. Hyposmotic solution (200 mosM) elicited ATP release from intact lenses and TRPV4 antagonists HC 067047 and RN 1734 prevented the release. In isosmotic solution, the TRPV4 agonist GSK1016790A (GSK) elicited ATP release. When propidium iodide (PI) (MW 668) was present in the bathing medium, GSK and hyposmotic solution both increased PI entry into the epithelium of intact lenses. Increased PI uptake and ATP release in response to GSK and hyposmotic solution were abolished by a mixture of agents that block connexin and pannexin hemichannels, 18α-glycyrrhetinic acid and probenecid. Increased Na-K-ATPase activity occurred in the epithelium of lenses exposed to GSK and 18α-glycyrrhetinic acid + probenecid prevented the response. Hyposmotic solution caused activation of Src family kinase and increased Na-K-ATPase activity in the lens epithelium and TRPV4 antagonists prevented the response. Ionomycin, which is known to increase cytoplasmic calcium, elicited ATP release, the magnitude of which was no greater when lenses were exposed simultaneously to ionomycin and hyposmotic solution. Ionomycin-induced ATP release was significantly reduced in calcium-free medium. TRPV4-mediated calcium entry was examined in Fura-2-loaded cultured lens epithelium. Hyposmotic solution and GSK both increased cytoplasmic calcium that was prevented by TRPV4 antagonists. The cytoplasmic calcium rise in response to hyposmotic solution or GSK was abolished when calcium was removed from the bathing solution. The findings are consistent with hyposmotic shock-induced TRPV4 channel activation which triggers hemichannel-mediated ATP release. The results point to TRPV4-mediated calcium entry that causes a cytoplasmic

  11. Distribution of a low dose compound within pharmaceutical tablet by using multivariate curve resolution on Raman hyperspectral images.

    PubMed

    Boiret, Mathieu; de Juan, Anna; Gorretta, Nathalie; Ginot, Yves-Michel; Roger, Jean-Michel

    2015-01-25

    In this work, Raman hyperspectral images and multivariate curve resolution-alternating least squares (MCR-ALS) are used to study the distribution of actives and excipients within a pharmaceutical drug product. This article is mainly focused on the distribution of a low dose constituent. Different approaches are compared, using initially filtered or non-filtered data, or using a column-wise augmented dataset before starting the MCR-ALS iterative process including appended information on the low dose component. In the studied formulation, magnesium stearate is used as a lubricant to improve powder flowability. With a theoretical concentration of 0.5% (w/w) in the drug product, the spectral variance contained in the data is weak. By using a principal component analysis (PCA) filtered dataset as a first step of the MCR-ALS approach, the lubricant information is lost in the non-explained variance and its associated distribution in the tablet cannot be highlighted. A sufficient number of components to generate the PCA noise-filtered matrix has to be used in order to keep the lubricant variability within the data set analyzed or, otherwise, work with the raw non-filtered data. Different models are built using an increasing number of components to perform the PCA reduction. It is shown that the magnesium stearate information can be extracted from a PCA model using a minimum of 20 components. In the last part, a column-wise augmented matrix, including a reference spectrum of the lubricant, is used before starting MCR-ALS process. PCA reduction is performed on the augmented matrix, so the magnesium stearate contribution is included within the MCR-ALS calculations. By using an appropriate PCA reduction, with a sufficient number of components, or by using an augmented dataset including appended information on the low dose component, the distribution of the two actives, the two main excipients and the low dose lubricant are correctly recovered. Copyright © 2014 Elsevier B

  12. How Langmuir-Blodgett trilayers act as templates for directed self-assembly of nanoparticles

    NASA Astrophysics Data System (ADS)

    Mukherjee, Smita; Datta, Alokmay; Biswas, Nupur; Giglia, Angelo; Nannarone, Stefano

    2014-04-01

    Atomic force microscopy (AFM) shows that Langmuir-Blodgett (LB) deposition of dissimilar metal stearates (MSt, M = Co, Zn, Cd) on templates of Co-stearate (Co-T) and Cd-stearate (Cd-T) results in self-assembly of MSts into nanocrystalline grains having clear and consistent morphological habits. The grains are better formed and well separated on Cd-T than on Co-T. Fourier transform infrared spectroscopy (FTIR) results show that the headgroup coordination of the overlayer is tuned by the coordination of the Cd-T template and remains unaffected by that of the Co-T template. They also indicate co-existence of a different kind of headgroup structure that is close to the undissociated fatty acid headgroup but differing more in the two types of carbon-oxygen bonds, suggesting an inter-headgroup bonding such as hydrogen bond that may exist on a nanocrystal surface. Results of synchrotron x-ray diffraction at C K-edge, of ZnSt on Cd-T (ZnSt/Cd-T) and Co-T (ZnSt/Co-T), point to a non-closed packed structure for ZnSt/Cd-T and a closed-packed structure for ZnSt/Co-T, with significant superlattice order in the former. The presence of crystalline phases of ZnSt in the nanometer scale, on LB templates, in contrast to the the presence of lamellar phase in bulk ZnSt, is attributed to the the presence of unidentate metal-carboxylate coordination in the former and absence of it in the latter, creating different gradients of dipolar forces at template overlayer interface. Relative strength of this long-range force over short-range intermolecular forces in the templates qualitatively explains better crystallinity and higher ordering in ZnSt/Cd-T compared to ZnSt/Co-T. We propose that the role of dipole moment gradient between template and overlayer in tuning of these metal-organic nanoparticles may be somewhat similar to structural and optical tunability of semiconductor nanocrystals by thermal and self-equilibrium strain.

  13. Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear.

    PubMed

    Fulton, J E; Pay, S R; Fulton, J E

    1984-01-01

    Cosmetics continue to be used by acne-prone individuals. Often as more acne develops, more cosmetics are applied. In order to protect against this natural tendency, physicians should provide more patient information on the currently available products and ingredients. This presentation is designed to help in that effort. The data presented were gleaned from the rabbit ear assay, which is not an ideal animal model but is the best we have. If an ingredient is negative in the rabbit ear assay, we feel it is safe on the acne-prone skin. A strong, positive ingredient or cosmetic should be avoided. Ingredient offenders include isopropyl myristate and its analogs, such as isopropyl palmitate, isopropyl isostearate, butyl stearate, isostearyl neopentanoate, myristyl myristate, decyl oleate, octyl stearate, octyl palmitate or isocetyl stearate, and new introductions by the cosmetic industry, such as propylene glycol-2 (PPG-2) myristyl propionate. Lanolins continue to be a problem, especially derivatives such as acetylated or ethoxylated lanolins. Our most troublesome recent finding is the comedogenic potential of the D & C Red dyes. They are universally used in the cosmetic industry, especially in blushers. This may explain the predominance of cosmetic acne in the cheekbone area. All of these D & C Red dyes tested to date, the xanthenes, monoazoanilines, fluorans, and indigoids, are comedogenic. Actually, this is not surprising as they are coal tar derivatives. The natural red pigment, carmine, is noncomedogenic and can serve as a substitute for D & C dyes in blushers. Many finished products are comedogenic. Most troublesome to the dermatologists are the therapeutic tools that we use, such as Liquimat, Retin-A cream, Hytone, Staticin, Sulfoxl, Desquam-X, and Persadox HP cream. These should be reformulated. We have been unable to confirm that precipitated sulfur (U.S.P.) is a potent comedogen in the rabbit ear assay. Clinically, we still find sulfur quite effective as an

  14. Triterpene Functional Genomics in Licorice for Identification of CYP72A154 Involved in the Biosynthesis of Glycyrrhizin[C][W][OA

    PubMed Central

    Seki, Hikaru; Sawai, Satoru; Ohyama, Kiyoshi; Mizutani, Masaharu; Ohnishi, Toshiyuki; Sudo, Hiroshi; Fukushima, Ery Odette; Akashi, Tomoyoshi; Aoki, Toshio; Saito, Kazuki; Muranaka, Toshiya

    2011-01-01

    Glycyrrhizin, a triterpenoid saponin derived from the underground parts of Glycyrrhiza plants (licorice), has several pharmacological activities and is also used worldwide as a natural sweetener. The biosynthesis of glycyrrhizin involves the initial cyclization of 2,3-oxidosqualene to the triterpene skeleton β-amyrin, followed by a series of oxidative reactions at positions C-11 and C-30, and glycosyl transfers to the C-3 hydroxyl group. We previously reported the identification of a cytochrome P450 monooxygenase (P450) gene encoding β-amyrin 11-oxidase (CYP88D6) as the initial P450 gene in glycyrrhizin biosynthesis. In this study, a second relevant P450 (CYP72A154) was identified and shown to be responsible for C-30 oxidation in the glycyrrhizin pathway. CYP72A154 expressed in an engineered yeast strain that endogenously produces 11-oxo-β-amyrin (a possible biosynthetic intermediate between β-amyrin and glycyrrhizin) catalyzed three sequential oxidation steps at C-30 of 11-oxo-β-amyrin supplied in situ to produce glycyrrhetinic acid, a glycyrrhizin aglycone. Furthermore, CYP72A63 of Medicago truncatula, which has high sequence similarity to CYP72A154, was able to catalyze C-30 oxidation of β-amyrin. These results reveal a function of CYP72A subfamily proteins as triterpene-oxidizing enzymes and provide a genetic tool for engineering the production of glycyrrhizin. PMID:22128119

  15. Insight into the role of dual-ligand modification in low molecular weight heparin based nanocarrier for targeted delivery of doxorubicin.

    PubMed

    Du, Hongliang; Liu, Mengrui; Yu, Aihua; Ji, Jianbo; Zhai, Guangxi

    2017-05-15

    Low molecular weight heparin nanoparticles (LMWH) modified by glycyrrhetinic acid (GA) (LMWH-GA) and further decorated by lactobionic acid (LA) (LA-LMWH-GA) were reported as novel hepatocellular carcinoma (HPC)-targeted carriers to overcome multidrug resistance (MDR) of doxorubicin (DOX). The drug-loaded nanoparticles had negative charge of around -25mV and average size range of 70-170nm. These nanoparticles performed sustained drug release in vitro and prolonged DOX residence time in blood circulation in vivo. Compared to free DOX, DOX-loaded nanoparticles demonstrated increased DOX accumulation in drug-resistance HepG2/ADR cells and enhanced in vitro therapeutic efficacy. However, DOX/LA-LMWH-GA with dual ligands didn't show higher cellular uptake and cytotoxicity than single GA modified DOX/LMWH-GA, although both GA-mediated and LA-mediated endocytosis were involved in their cell internalization. Uptake pathway inhibition study revealed the less efficacy of DOX/LA-LMWH-GA in cellular level could be attributed to the reduced effect of micropinocytosis and caveolae-mediated endocytosis in cellular uptake. Interestingly, the DOX-loaded nanoparticles developed from lower drug/carrier feeding ratio possessed higher performance in cell internalization and in vitro efficacy compared to those developed from higher drug/carrier feeding ratio, which could highlight the role of carrier in drug delivery process. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Biological activity of some naturally occurring resins, gums and pigments against in vitro LDL oxidation.

    PubMed

    Andrikopoulos, Nikolaos K; Kaliora, Andriana C; Assimopoulou, Andreana N; Papapeorgiou, Vassilios P

    2003-05-01

    Naturally occurring gums and resins with beneficial pharmaceutical and nutraceutical properties were tested for their possible protective effect against copper-induced LDL oxidation in vitro. Chiosmastic gum (CMG) (Pistacia lentiscus var. Chia resin) was the most effective in protecting human LDL from oxidation. The minimum and maximum doses for the saturation phenomena of inhibition of LDL oxidation were 2.5 mg and 50 mg CMG (75.3% and 99.9%, respectively). The methanol/water extract of CMG was the most effective compared with other solvent combinations. CMG when fractionated in order to determine a structure-activity relationship showed that the total mastic essential oil, collofonium-like residue and acidic fractions of CMG exhibited a high protective activity ranging from 65.0% to 77.8%. The other natural gums and resins (CMG resin 'liquid collection', P. terebinthus var. Chia resin, dammar resin, acacia gum, tragacanth gum, storax gum) also tested as above, showed 27.0%-78.8% of the maximum LDL protection. The other naturally occurring substances, i.e. triterpenes (amyrin, oleanolic acid, ursolic acid, lupeol, 18-a-glycyrrhetinic acid) and hydroxynaphthoquinones (naphthazarin, shikonin and alkannin) showed 53.5%-78.8% and 27.0%-64.1% LDL protective activity, respectively. The combination effects (68.7%-76.2% LDL protection) of ursolic-, oleanolic- and ursodeoxycholic- acids were almost equal to the effect (75.3%) of the CMG extract in comparable doses.

  17. GABAergic responses of mammalian ependymal cells in the central canal neurogenic niche of the postnatal spinal cord.

    PubMed

    Corns, Laura F; Deuchars, Jim; Deuchars, Susan A

    2013-10-11

    The area surrounding the central canal of the postnatal mammalian spinal cord is a highly plastic region that exhibits many similarities to other postnatal neurogenic niches, such as the subventricular zone. Within this region, ependymal cells have been identified as neural stem cells however very little is known about their properties and how the local environment, including neurotransmitters, is capable of affecting them. The neurotransmitter GABA is present around the central canal and is known to affect cells within other postnatal neurogenic niches. This study used whole cell patch clamp electrophysiology and intracellular dye-loading in in vitro Wistar rat spinal cord slices to characterise ependymal cells and their ability to respond to GABA. Ependymal cells were defined by their passive response properties and low input resistances. Extensive dye-coupling was observed between ependymal cells; this was confirmed as gap junction coupling using the gap junction blocker, 18β-glycyrrhetinic acid, which significantly increased the input resistance of ependymal cells. GABA depolarised all ependymal cells tested; the partial antagonism of this response by bicuculline and gabazine indicates that GABA(A) receptors contribute to this response. A lack of effect by baclofen suggests that GABA(B) receptors do not contribute to the GABAergic response. The ability of ependymal cells to respond to GABA suggests that GABA could be capable of influencing the proliferation and differentiation of cells within the neurogenic niche of the postnatal spinal cord.

  18. Metabolism of bupropion by baboon hepatic and placental microsomes

    PubMed Central

    Wang, Xiaoming; Abdelrahman, Doaa R.; Fokina, Valentina M.; Hankins, Gary D.V.; Ahmed, Mahmoud S.; Nanovskaya, Tatiana N.

    2011-01-01

    The aim of this investigation was to determine the biotransformation of bupropion by baboon hepatic and placental microsomes, identify the enzyme(s) catalyzing the reaction(s) and determine its kinetics. Bupropion was metabolized by baboon hepatic and placental microsomes to hydroxybupropion (OH-BUP), threo- (TB) and erythrohydrobupropion (EB). OH-bupropion was the major metabolite formed by hepatic microsomes (Km 36 ± 6 µM, Vmax 258 ± 32 pmol mg protein−1 min−1), however the formation of OH-BUP by placental microsomes was below the limit of quantification. The apparent Km values of bupropion for the formation of TB and EB by hepatic and placental microsomes were similar. The selective inhibitors of CYP2B6 (ticlopidine and phencyclidine) and monoclonal antibodies raised against human CYP2B6 isozyme caused 80% inhibition of OH-BUP formation by baboon hepatic microsomes. The chemical inhibitors of aldo-keto reductases (flufenamic acid), carbonyl reductases (menadione), and 11β-hydroxysteroid dehydrogenases (18β-glycyrrhetinic acid) significantly decreased the formation of TB and EB by hepatic and placental microsomes. Data indicate that CYP2B of baboon hepatic microsomes is responsible for biotransformation of bupropion to OH-BUP, while hepatic and placental short chain dehydrogenases/reductases and to a lesser extent aldo-keto reductases are responsible for the reduction of bupropion to TB and EB. PMID:21570381

  19. Roles of phytochemicals in amino acid nutrition.

    PubMed

    Kong, Xiangfeng; Wu, Guoyao; Yin, Yinlong

    2011-01-01

    Chinese herbal medicine (CHM) is often used as dietary supplements to maintain good health in animals and humans. Here, we review the current knowledge about effects of CHM (including ultra-fine Chinese herbal powder, Acanthopanax senticosus extracts, Astragalus polysaccharide, and glycyrrhetinic acid) as dietary additives on physiological and biochemical parameters in pigs, chickens and rodents. Additionally, we propose possible mechanisms for the beneficial effects of CHM on the animals. These mechanisms include (a) increased digestion and absorption of dietary amino acids; (b) altered catabolism of amino acids in the small intestine and other tissues; (c) enhanced synthesis of functional amino acids (e.g., arginine, glutamine and proline) and polyamines; and (d) improved metabolic control of nutrient utilization through cell signaling. Notably, some phytochemicals and glucocorticoids share similarities in structure and physiological actions. New research findings provide a scientific and clinical basis for the use of CHM to improve well-being in livestock species and poultry, while enhancing the efficiency of protein accretion. Results obtained from animal studies also have important implications for human nutrition and health.

  20. Functional assessment of gap junctions in monolayer and three-dimensional cultures of human tendon cells using fluorescence recovery after photobleaching.

    PubMed

    Kuzma-Kuzniarska, Maria; Yapp, Clarence; Pearson-Jones, Thomas W; Jones, Andrew K; Hulley, Philippa A

    2014-01-01

    Gap junction-mediated intercellular communication influences a variety of cellular activities. In tendons, gap junctions modulate collagen production, are involved in strain-induced cell death, and are involved in the response to mechanical stimulation. The aim of the present study was to investigate gap junction-mediated intercellular communication in healthy human tendon-derived cells using fluorescence recovery after photobleaching (FRAP). The FRAP is a noninvasive technique that allows quantitative measurement of gap junction function in living cells. It is based on diffusion-dependent redistribution of a gap junction-permeable fluorescent dye. Using FRAP, we showed that human tenocytes form functional gap junctions in monolayer and three-dimensional (3-D) collagen I culture. Fluorescently labeled tenocytes following photobleaching rapidly reacquired the fluorescent dye from neighboring cells, while HeLa cells, which do not communicate by gap junctions, remained bleached. Furthermore, both 18 β-glycyrrhetinic acid and carbenoxolone, standard inhibitors of gap junction activity, impaired fluorescence recovery in tendon cells. In both monolayer and 3-D cultures, intercellular communication in isolated cells was significantly decreased when compared with cells forming many cell-to-cell contacts. In this study, we used FRAP as a tool to quantify and experimentally manipulate the function of gap junctions in human tenocytes in both two-dimensional (2-D) and 3-D cultures.

  1. Strain uses gap junctions to reverse stimulation of osteoblast proliferation by osteocytes.

    PubMed

    Suswillo, Rosemary F L; Javaheri, Behzad; Rawlinson, Simon C F; Dowthwaite, Gary P; Lanyon, Lance E; Pitsillides, Andrew A

    2017-01-01

    Identifying mechanisms by which cells of the osteoblastic lineage communicate in vivo is complicated by the mineralised matrix that encases osteocytes, and thus, vital mechanoadaptive processes used to achieve load-bearing integrity remain unresolved. We have used the coculture of immunomagnetically purified osteocytes and primary osteoblasts from both embryonic chick long bone and calvariae to examine these mechanisms. We exploited the fact that purified osteocytes are postmitotic to examine both their effect on proliferation of primary osteoblasts and the role of gap junctions in such communication. We found that chick long bone osteocytes significantly increased basal proliferation of primary osteoblasts derived from an identical source (tibiotarsi). Using a gap junction inhibitor, 18β-glycyrrhetinic acid, we also demonstrated that this osteocyte-related increase in osteoblast proliferation was not reliant on functional gap junctions. In contrast, osteocytes purified from calvarial bone failed to modify basal proliferation of primary osteoblast, but long bone osteocytes preserved their proproliferative action upon calvarial-derived primary osteoblasts. We also showed that coincubated purified osteocytes exerted a marked inhibitory action on mechanical strain-related increases in proliferation of primary osteoblasts and that this action was abrogated in the presence of a gap junction inhibitor. These data reveal regulatory differences between purified osteocytes derived from functionally distinct bones and provide evidence for 2 mechanisms by which purified osteocytes communicate with primary osteoblasts to coordinate their activity. Copyright © 2017 The Authors Cell Biochemistry and Function published by John Wiley & Sons Ltd.

  2. Anti-tubercular agents from Glycyrrhiza glabra.

    PubMed

    Kalani, Komal; Chaturvedi, Vinita; Alam, Sarfaraz; Khan, Feroz; Srivastava, Santosh Kumar

    2015-01-01

    Bioactivity guided isolation of Glycyrrhiza glabra (Leguminosae / Fabaceae) roots resulted in the characterization of 18β-glycyrrhetinic acid as a major anti-tubercular agent. Further, GA-1 was semi-synthetically converted into its nine derivatives, which were in-vitro evaluated for their antitubercular potential against Mycobacterium tuberculosis H37Rv using BACTEC-460 radiometric susceptibility assay. All the derivatives were active, but the benzylamide (GA-8, MIC 12.5μg/ml) and ethyl oxylate (GA-3, MIC 25.0 μg/ml) derivatives were significantly active against the pathogen. This was further supported by the molecular docking studies, which showed adequate docking (LibDock) scores for GA-3 (120.3) and GA-8 (112.6) with respect to the standard anti-tubercular drug, rifampicin (92.94) on the DNA-directed RNA polymerase subunit beta (rpoB) target site. Finally, the in silico pharmacokinetic and drug-likeness studies showed that GA-3 and GA- 8 possesses drug-like properties. This is the first ever report on the anti-tubercular potential of GA and its derivatives. These results may be of great help in anti-tubercular drug development from a very common, inexpensive, and non toxic natural product.

  3. Influence of certain ingredients on the SPF determined in vivo.

    PubMed

    Couteau, Céline; Chauvet, Catherine; Paparis, Eva; Coiffard, Laurence J M

    2012-12-01

    When determined in vitro, the SPF of certain commercial sunscreen products can be lower than the SPF indicated on the label. The study of the composition of this type of product enabled us to note that the majority contained substances reputed to have anti-inflammatory properties. This effect is shown by inhibiting the erythema, without protecting the skin, which constitutes a serious public health problem. The anti-inflammatory effects of αbisabolol-, allantoin- and 18-β-glycyrrhetinic acid-based emulsions, as well as commercial sun products containing any one of these molecules, have been tested with phorbol myristate acetate on mice. The effectiveness of these sunscreens products is quantified using two indicators: SPF (sun protection factor) and PF-UVA (protection factor-UVA) by in vitro method. We were thus able to show that certain sun products have an anti-inflammatory effect, which in turn causes the SPF value shown on the product to be overestimated, indeed sometimes by considerably large margins.

  4. Influences of yokukansankachimpihange on aggressive behavior of zinc-deficient mice and actions of the ingredients on excessive neural exocytosis in the hippocampus of zinc-deficient rats

    PubMed Central

    Tamano, Haruna; Yusuke, Enya; Ide, Kazuki; Takeda, Atsushi

    2016-01-01

    We examined the effect of Yokukansankachimpihange (YKSCH), a form of Yokukansan containing parts of two herbaceous plants, Citrus Unshiu Peel (Chimpi) and Pinellia Tuber (Hange), on aggressive behavior of mice housed individually. Mice were fed a zinc-deficient diet for 2 weeks. In a resident-intruder test, the cumulative duration of aggressive behavior was decreased in zinc-deficient mice administrated drinking water containing YKSCH (approximately 300 mg/kg body weight/day) for 2 weeks. We tested mice for geissoschizine methyl ether (GM), which is contained in Uncaria Hook, and 18β-glycyrrhetinic acid (GA), a major metabolite of glycyrrhizin contained in Glycyrrhiza, which were contained in YKS and YKSCH. In hippocampal slices from zinc-deficient rats, excess exocytosis at mossy fiber boutons induced with 60 mM KCl was attenuated in the presence of GA (100–500 µM) or GM (100 µM). The intracellular Ca2+ level, which showed an increase induced by 60 mM KCl, was also attenuated in the presence of GA (100–500 µM) or GM (100 µM). These results suggest that GA and GM ameliorate excess glutamate release from mossy fiber boutons by suppressing the increase in intracellular Ca2+ signaling. These ameliorative actions may contribute to decreasing the aggressiveness of mice individually housed under zinc deficiency, potentially by suppressing excess glutamatergic neuron activity in the hippocampus. PMID:27245118

  5. Human dehydrogenase/reductase (SDR family) member 11 is a novel type of 17β-hydroxysteroid dehydrogenase.

    PubMed

    Endo, Satoshi; Miyagi, Namiki; Matsunaga, Toshiyuki; Hara, Akira; Ikari, Akira

    2016-03-25

    We report characterization of a member of the short-chain dehydrogenase/reductase superfamily encoded in a human gene, DHRS11. The recombinant protein (DHRS11) efficiently catalyzed the conversion of the 17-keto group of estrone, 4- and 5-androstenes and 5α-androstanes into their 17β-hydroxyl metabolites with NADPH as a coenzyme. In contrast, it exhibited reductive 3β-hydroxysteroid dehydrogenase activity toward 5β-androstanes, 5β-pregnanes, 4-pregnenes and bile acids. Additionally, DHRS11 reduced α-dicarbonyls (such as diacetyl and methylglyoxal) and alicyclic ketones (such as 1-indanone and loxoprofen). The enzyme activity was inhibited in a mixed-type manner by flavonoids, and competitively by carbenoxolone, glycyrrhetinic acid, zearalenone, curcumin and flufenamic acid. The expression of DHRS11 mRNA was observed widely in human tissues, most abundantly in testis, small intestine, colon, kidney and cancer cell lines. Thus, DHRS11 represents a novel type of 17β-hydroxysteroid dehydrogenase with unique catalytic properties and tissue distribution.

  6. Low-intensity pulsed ultrasound (LIPUS) and cell-to-cell communication in bone marrow stromal cells.

    PubMed

    Sena, Kotaro; Angle, Siddhesh R; Kanaji, Arihiko; Aher, Chetan; Karwo, David G; Sumner, Dale R; Virdi, Amarjit S

    2011-07-01

    Low-intensity pulsed ultrasound (LIPUS) is an established therapy for fracture repair and has been used widely in the clinics, but its underlying mechanism of action remains unclear. The aim of the current research was to determine the effect of LIPUS on gap junctional cell-to-cell intercellular communication in rat bone marrow stromal cells (BMSC) in vitro and to determine whether the ability of BMSCs to communicate by gap junctions would affect their response to LIPUS. Single or daily-multiple LIPUS treatment at 1.5MHz, 30mW/cm(2), for 20min was applied to BMSC. We demonstrated that BMSC form functional gap junctions and single LIPUS treatment significantly increased the intracellular dye transfer between BMSC. In addition, activated phosphorylation of ERK1/2 and p38 by LIPUS stimulation was diminished when cells were treated with a gap junction inhibitor 18β-glycyrrhetinic acid (18β). We further demonstrated that 18β diminished the significant increase in alkaline phosphatase activity following LIPUS stimulation. These results suggest a potential role of gap junctional cell-to-cell intercellular communication on the effects of LIPUS in BMSC.

  7. Qualitative/Chemical Analyses of Ankaferd Hemostat and Its Antioxidant Content in Synthetic Gastric Fluids

    PubMed Central

    Koluman, Ahmet; Akar, Nejat; Malkan, Umit Y.; Haznedaroglu, Ibrahim C.

    2016-01-01

    Introduction. Ankaferd hemostat (ABS) is the first topical haemostatic agent involving the red blood cell-fibrinogen interactions. The antihemorrhagic efficacy of ABS has been tested in controlled clinical trials. The drug induces the formation of an encapsulated complex protein web with vital erythroid aggregation. The aim of this study is to detect the essential toxicity profile and the antioxidant molecules inside ABS. Methods. The pesticides were analyzed by GC-MS and LC-MS. The determination by ICP-MS after pressure digestion was performed for the heavy metals. HPLC was used for the detection of mycotoxins. Dioxin Response Chemically Activated Luciferase Gene Expression method was used for the dioxin evaluation. TOF-MS and spectra data were evaluated to detect the antioxidants and other molecules. Results. TOF-MS spectra revealed the presence of several antioxidant molecules (including tocotrienols, vitamin E, tryptophan, estriol, galangin, apigenin, oenin, 3,4-divanillyltetrahydrofuran, TBHQ, thymol, BHA, BHT, lycopene, glycyrrhetinic acid, and tomatine), which may have clinical implications in the pharmacobiological actions of ABS. Conclusion. The safety of ABS regarding the presence of heavy metals, pesticides, mycotoxins, GMO and dioxins, and PCBs was demonstrated. Thus the present toxicological results indicated the safety of ABS. The antioxidant content of ABS should be investigated in future studies. PMID:26925418

  8. The comparative pharmacokinetics of four bioactive ingredients after administration of Ramulus Cinnamomi-Radix Glycyrrhizae herb pair extract, Ramulus Cinnamomi extract and Radix Glycyrrhizae extract.

    PubMed

    Wang, Shengnan; Sun, Lijiao; Gu, Liqiang; Zhang, Yuanyuan; Zhao, Simin; Zhao, Long-Shan; Bi, Kai-Shun; Chen, Xiaohui

    2016-08-01

    Ramulus Cinnamomi (RC)-Radix Glycyrrhizae (RG) is a classic herb pair, which is commonly used as a fixed form to treat cardiovascular disease in the clinic. Our work aimed to compare the pharmacokinetic difference of cinnamic acid, liquiritin, isoliquiritigenin and glycyrrhetinic acid in rats after oral administration of the RC-RG herb pair extracts [Guizhigancao Decoction (GGD) and Lingguizhugan Decoction (LGZGD)] and the single RC or RG extract. A HPLC-MS method was developed and validated to study comparative pharmacokinetics. The pharmacokinetic parameters (Cmax , AUC, MRT) of four compounds between the RC-RG herb pair group and the single herb (RC or RG) group showed significant differences (p < 0.05). Compared with the single herb (RC or RG) group, higher peak concentration, slower elimination and larger exposure could be observed after giving the RC-RG herb-pair extracts. The pharmacokinetic differences might indicate the relativity of remedy in the RC-RG herb pair and provide scientific information for rational administration of the drug in the clinic. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. MRP transporters as membrane machinery in the bradykinin-inducible export of ATP.

    PubMed

    Zhao, Yumei; Migita, Keisuke; Sun, Jing; Katsuragi, Takeshi

    2010-04-01

    Adenosine triphosphate (ATP) plays the role of an autocrine/paracrine signal molecule in a variety of cells. So far, however, the membrane machinery in the export of intracellular ATP remains poorly understood. Activation of B2-receptor with bradykinin-induced massive release of ATP from cultured taenia coli smooth muscle cells. The evoked release of ATP was unaffected by gap junction hemichannel blockers, such as 18alpha-glycyrrhetinic acid and Gap 26. Furthermore, the cystic fibrosis transmembrane regulator (CFTR) coupled Cl(-) channel blockers, CFTR(inh)172, 5-nitro-2-(3-phenylpropylamino)-benzoic acid, Gd3(+) and glibenclamide, failed to suppress the export of ATP by bradykinin. On the other, the evoked release of ATP was greatly reduced by multidrug resistance protein (MRP) transporter inhibitors, MK-571, indomethacin, and benzbromarone. From western blotting analysis, blots of MRP 1 protein only, but not MRP 2 and MRP 3 protein, appeared at 190 kD. However, the MRP 1 protein expression was not enhanced after loading with 1 muM bradykinin for 5 min. Likewise, niflumic acid and fulfenamic acid, Ca2(+)-activated Cl(-) channel blockers, largely abated the evoked release of ATP. The possibility that the MRP transporter system couples with Ca2(+)-activated Cl(-) channel activities is discussed here. These findings suggest that MRP transporters, probably MRP 1, unlike CFTR-Cl(-) channels and gap junction hemichannels, may contribute as membrane machinery to the export of ATP induced by G-protein-coupled receptor stimulation.

  10. Kinetics and mechanism of intercellular ice propagation in a micropatterned tissue construct.

    PubMed Central

    Irimia, Daniel; Karlsson, Jens O M

    2002-01-01

    Understanding the effects of cell-cell interaction on intracellular ice formation (IIF) is required to design optimized protocols for cryopreservation of tissue. To determine the effects of cell-cell interactions during tissue freezing, without confounding effects from uncontrolled factors (such as time in culture, cell geometry, and cell-substrate interactions), HepG2 cells were cultured in pairs on glass coverslips micropatterned with polyethylene glycol disilane, such that each cell interacted with exactly one adjacent cell. Assuming the cell pair to be a finite state system, being either in an unfrozen state (no ice in either cell), a singlet state (IIF in one cell only), or a doublet state (IIF in both cells), the kinetics of state transitions were theoretically modeled and cryomicroscopically measured. The rate of intercellular ice propagation, estimated from the measured singlet state probability, increased in the first 24 h of culture and remained steady thereafter. In cell pairs cultured for 24 h and treated with the gap junction blocker 18beta-glycyrrhetinic acid before freezing, the intercellular ice propagation rate was lower than in untreated controls (p < 0.001), but significantly greater than zero (p < 0.0001). These results suggest that gap junctions mediate some, but not all, mechanisms of ice propagation in tissue. PMID:11916845

  11. Functional assessment of gap junctions in monolayer and three-dimensional cultures of human tendon cells using fluorescence recovery after photobleaching

    NASA Astrophysics Data System (ADS)

    Kuzma-Kuzniarska, Maria; Yapp, Clarence; Pearson-Jones, Thomas W.; Jones, Andrew K.; Hulley, Philippa A.

    2014-01-01

    Gap junction-mediated intercellular communication influences a variety of cellular activities. In tendons, gap junctions modulate collagen production, are involved in strain-induced cell death, and are involved in the response to mechanical stimulation. The aim of the present study was to investigate gap junction-mediated intercellular communication in healthy human tendon-derived cells using fluorescence recovery after photobleaching (FRAP). The FRAP is a noninvasive technique that allows quantitative measurement of gap junction function in living cells. It is based on diffusion-dependent redistribution of a gap junction-permeable fluorescent dye. Using FRAP, we showed that human tenocytes form functional gap junctions in monolayer and three-dimensional (3-D) collagen I culture. Fluorescently labeled tenocytes following photobleaching rapidly reacquired the fluorescent dye from neighboring cells, while HeLa cells, which do not communicate by gap junctions, remained bleached. Furthermore, both 18 β-glycyrrhetinic acid and carbenoxolone, standard inhibitors of gap junction activity, impaired fluorescence recovery in tendon cells. In both monolayer and 3-D cultures, intercellular communication in isolated cells was significantly decreased when compared with cells forming many cell-to-cell contacts. In this study, we used FRAP as a tool to quantify and experimentally manipulate the function of gap junctions in human tenocytes in both two-dimensional (2-D) and 3-D cultures.

  12. Comparison between conventional indirect competitive enzyme-linked immunosorbent assay (icELISA) and simplified icELISA for small molecules.

    PubMed

    Zhao, Jing; Li, Gang; Yi, Guo-Xiang; Wang, Bao-Min; Deng, Ai-Xing; Nan, Tie-Gui; Li, Zhao-Hu; Li, Qing X

    2006-06-30

    A simplified indirect competitive enzyme-linked immunosorbent assay (icELISA) for small molecules was established by modifying the procedure of conventional icELISA. The key change was that the analyte, antibody, and enzyme-labeled second antibody in the simplified icELISA were added in one step, whereas in conventional icELISA these reagents were added in two separate steps. Three small chemicals, namely zeatin riboside, glycyrrhetinic acid, and chlorimuron-ethyl, were used to verify the new assay format and compare the results obtained from conventional icELISA and simplified icELISA. The results indicated that, under optimized conditions, the new assay offered several advantages over the conventional icELISA, which are simpler, less time consuming and higher sensitive although it requires more amount of reagents. The assay sensitivity (IC50) was improved for 1.2-1.4-fold. Four licorice roots samples were analyzed by conventional icELISA and simplified icELISA, as well as liquid chromatography (LC). There was no significant difference among the content obtained from the three methods for each sample. The correlation between data obtained from conventional icELISA and simplified icELISA analyses was 0.9888. The results suggest that the simplified icELISA be useful for high throughput screening of small molecules.

  13. Role of connexin-43 hemichannels in the pathogenesis of Yersinia enterocolitica.

    PubMed

    Velasquez Almonacid, L A; Tafuri, S; Dipineto, L; Matteoli, G; Fiorillo, E; Della Morte, R; Fioretti, A; Menna, L F; Staiano, N

    2009-12-01

    Connexin (Cx) channels are sites of cytoplasmic communication between contacting cells. Evidence indicates that the opening of hemichannels occurs under both physiological and pathological conditions. In this paper, the involvement of Cx-43 hemichannels is demonstrated in the pathogenesis of Yersinia. Parental HeLa cells and transfected HeLa cells stably expressing Cx-43 (HCx43) were infected with Yersiniaenterocolitica, and bacterial uptake was measured by the colony-forming unit method. Bacterial uptake was higher in HCx43 cells than in parental cells and was inhibited by the Cx channel blocker, 18-alpha-glycyrrhetinic acid (AGA). The inhibitory effect of AGA was more pronounced on the Y. enterocolitica uptake by HCx43 cells than by parental cells. The ability of HCx43 cells to incorporate the permeable fluorescent tracer Lucifer Yellow (LY) was assessed. Dye incorporation was inhibited by AGA, whereas Y. enterocolitica infection of HCx43 cells increased LY incorporation. Western blotting analysis demonstrated that Y. enterocolitica infection of HCx43 cells induced tyrosine phosphorylation of Cx-43, thus supporting a critical role for Cx-43 in the strategies exploited by bacterial pathogens to invade non-phagocytic cells.

  14. The protective effect of functional connexin43 channels on a human epithelial cell line exposed to oxidative stress.

    PubMed

    Hutnik, Cindy M L; Pocrnich, Cady E; Liu, Hong; Laird, Dale W; Shao, Qing

    2008-02-01

    To determine the role of connexin43 (Cx43) and gap junctional intercellular communication (GJIC) in the response of the human retinal pigment epithelial cell line ARPE-19 to oxidative stress. ARPE-19 cells were treated with the chemical oxidant tert-butyl hydroperoxide (t-BOOH), and cell viability was assessed by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. GJIC was evaluated by scrape loading/dye transfer and microinjection assays, and Cx43 expression was detected by Western blot and immunofluorescent staining combined with confocal microscopy analysis. Retroviral infection of ARPE-19 cells with shRNA vectors targeting Cx43 or vectors encoding Cx43, Cx26, and a disease-linked dominant negative Cx43 mutant (G21R) were used, and the effect on cell viability was assessed. t-BOOH-induced ARPE-19 cell death was correlated with reductions in GJIC and in the total level of Cx43 protein expression. Overexpression of Cx26 and Cx43 increased the viability of oxidant-treated ARPE-19 cells. Conversely, shRNA knockdown of Cx43, expression of a disease-linked dominant negative Cx43 mutant, and blocking GJIC with 18beta-glycyrrhetinic acid and flufenamic acid all increased t-BOOH-induced ARPE-19 cell death. Cx43-mediated protection of ARPE-19 cells from oxidative stress-induced death is dependent on functional Cx43 channels.

  15. Gap junction channels reconstituted in two closely apposed lipid bilayers.

    PubMed

    Ramundo-Orlando, Alfonsina; Serafino, Annalucia; Villalobo, Antonio

    2005-04-01

    Intercellular communication mediated by gap junction channels plays an important role in many cellular processes. In contrast to other channels, gap junction channels span two plasma membranes resulting in an intracellular location for both ends of the junctional pore and the regulatory sites for channel gating. This configuration presents unique challenges for detailed experimental studies of junctional channel physiology and ligand-activation in situ. Availability of an appropriate model system would significantly facilitate future studies of gap junction channel function and structure. Here we show that the double-membrane channel can be reconstituted in pairs of closely apposed lipid bilayers, as experienced in cells. We have trapped the calcium-sensitive dye, arsenazo III (AIII), partially calcium-saturated (AIII-Ca), in one population of connexin32 reconstituted-liposomes, and EGTA in a second one. In such mixtures, the interaction of EGTA with AIII-Ca was measured by a large color shift from blue to red (decreased absorbance at 652 nm). The exchange of these compounds through gap junctions was proportional to these decrements. Results indicate that these connexon-mediated interliposomal channels are functional and are inhibited by the addition of alpha-glycyrrhetinic acid and by flufenamic acid, two gap junction communication inhibitors. Future use of this model system has the potential to improve our understanding of the permeability and modulation of junctional channels in its native intercellular assembly.

  16. Cortisone induces insulin resistance in C2C12 myotubes through activation of 11beta-hydroxysteroid dehydrogenase 1 and autocrinal regulation.

    PubMed

    Park, Seung Yeon; Bae, Ji Hyun; Cho, Young Sik

    2014-04-01

    The enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) is known to catalyse inactive glucocorticoids into active forms, and its dysregulation in adipose and muscle tissues has been implicated in the development of metabolic syndrome. To delineate the molecular mechanism by which active cortisol has an antagonizing effect against insulin, we optimized the metabolic production of cortisol and its biological functions in myotubes (C2C12). Myotubes supplemented with cortisone actively catalysed its conversion into cortisol, which in turn abolished phosphorylation of Akt in response to insulin treatment. This led to diminished uptake of insulin-induced glucose. This was corroborated by the application of 11β-HSD1 inhibitor glycyrrhetinic acid and a glucocorticoid receptor antagonist RU-486, which reversed completely the antagonizing effects of cortisol on insulin action. Therefore, development of specific inhibitors targeting 11β-HSD1 might be a promising way to improve impaired insulin-stimulated glucose uptake. Copyright © 2013 John Wiley & Sons, Ltd.

  17. Synthesis of liver-targeting dual-ligand modified GCGA/5-FU nanoparticles and their characteristics in vitro and in vivo

    PubMed Central

    Cheng, Mingrong; Gao, Xiaoyan; Wang, Yong; Chen, Houxiang; He, Bing; Li, Yingchun; Han, Jiang; Zhang, Zhiping

    2013-01-01

    Nanoparticle drug delivery systems using polymers hold promise for clinical applications. We synthesized dual-ligand modified chitosan (GCGA) nanoparticles using lactic acid, glycyrrhetinic acid, and chitosan to target the liver in our previous studies. We then synthesized the GCGA/5-FU nanoparticles by conjugating 5-fluorouracil (5-FU) onto the GCGA nanomaterial, which had a mean particle size of 239.9 nm, a polydispersity index of 0.040, a zeta potential of +21.2 mV, and a drug loading of 3.90%. GCGA/5-FU nanoparticles had good slow release properties, and the release process could be divided into five phases: small burst release, gentle release, second burst release, steady release, and slow release. Inhibitory effects of GCGA/5-FU on tumor cells targeted the liver, and were time and dose dependent. GCGA nanoparticles significantly prolonged the efficacy of 5-FU on tumor cells, and alleviated the resistance of tumor cells to 5-FU. GCGA/5-FU nanoparticles were mostly concentrated in the liver, indicating that the GCGA nanoparticles were liver targeting. GCGA/5-FU nanoparticles significantly suppressed tumor growth in orthotopic liver transplantation mouse model, and improved mouse survival. PMID:24232303

  18. UHPLC-MS/MS quantification combined with chemometrics for the comparative analysis of different batches of raw and wine-processed Dipsacus asper.

    PubMed

    Tao, Yi; Du, Yingshan; Su, Dandan; Li, Weidong; Cai, Baochang

    2017-02-20

    A rapid and sensitive ultra high performance liquid chromatography with tandem mass spectrometry approach was established for the simultaneous determination of 4-caffeoylquinic acid, loganic acid, chlorogenic acid, loganin, 3,5-dicaffeoylquinic acid, dipsacoside B, asperosaponin VI and sweroside in raw and wine-processed Dipsacus asper. Chloramphenicol and glycyrrhetinic acid were employed as internal standards. The proposed approach was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery. Intra- and inter-assay variability for all analytes were 2.8-4.9 and 1.7-4.8%, respectively. The standard addition method determined recovery rates for each analytes (96.8-104.6%). In addition, the developed approach was applied to 20 batches of raw and wine-processed samples of Dipsacus asper. Principle component analysis and partial least squares-discriminate analysis revealed a clear separation between the raw group and wine-processed group. After wine-processing, the contents of loganic acid, chlorogenic acid, dipsacoside B and asperosaponin VI were up-regulated, whilst the contents of 3,5-dicaffeoylquinic acid, 4-caffeoylquinic acid, loganin and sweroside were down-regulated. Our results demonstrated that ultra high performance liquid chromatography with tandem mass spectrometry quantification combined with chemometrics is a viable method for quality evaluation of the raw Dipsacus asper and its wine-processed products. This article is protected by copyright. All rights reserved.

  19. [LC-MS quantification and pharmacokinetics of the multi-constituents of Huangqin Tang in rat plasma after different single oral doses].

    PubMed

    Li, Tao; Wang, Yi-Wei; Wang, Yan-Li; Liang, Ri-Xin; Zhang, Dong; Zhang, Hui-Hui; Chen, Li; Zhou, Zhong-Ming; Yang, Wei-Peng

    2013-06-01

    The current study aims to investigate the pharmacokinetic properties of Huangqin Tang on different oral doses. An LC-MS method for simultaneous determination of flavonoids and terpenoids in rat plasma was developed and validated. Plasma samples were treated with hydrochloric acid (containing 1% ascorbic acid), precipitated with acetonitrile, separated on a Zorbax SB-C18 column, detected by single quadruple mass spectrometry with an electrospray ionization interface, and quantified using selected ion monitoring mode. All pharmacokinetic parameters were processed by non-compartmental analysis using WinNonlin software. The results of specificity, linearity, intra-day and inter-day precisions, accuracy, and stability for LC-MS assay were suitable for the quantification of paeoniflorin, baicalin, wogonoside, baicalein, wogonin, oroxylin A, glycyrrhizic acid and glycyrrhetinic acid in rat plasma. The concentration-time profiles of baicalin, wogonoside, baicalein, wogonin, oroxylin A and glycyrrhizic acid showed double-peak phenomenon after Huangqin Tang was orally administered at 40 g x kg(-1) dose; all eight constituents in rat plasma showed good dose-exposure relationship within the dosage of 10-40 g x kg(-1); although plasma concentrations were different, the flavonoids with the same backbone showed the similar fate in the body with the corresponding dosage. In conclusion, the LC-MS assay was successfully applied for the pharmacokinetic study of multi-constituents of Huangqin Tang with different doses. Additionally, these constituents demonstrated good pharmacokinetic properties in the body.

  20. Triterpenes suppress octanoylated ghrelin production in ghrelin-expressing human gastric carcinoma cells.

    PubMed

    Nakajima, Kensuke; Oiso, Shigeru; Uto, Takuhiro; Morinaga, Osamu; Shoyama, Yukihiro; Kariyazono, Hiroko

    2016-01-01

    Ghrelin is an appetite-stimulating peptide hormone with an octanoyl modification at serine 3 that is essential for its orexigenic effect. Ghrelin O-acyltransferase (GOAT) is the enzyme that catalyzes ghrelin acylation using fatty acyl-coenzyme A as a substrate. We previously developed an assay system based on the AGS-GHRL8 cell line that produces octanoylated ghrelin in the presence of octanoic acid, and demonstrated that some fatty acids suppressed octanoylated ghrelin production. Recent studies have reported that triterpenes have anti-obesity effect. Since such triterpenes, like fatty acids, have a carboxyl group, we speculated that they can suppress octanoylated ghrelin production. To test this hypothesis, we investigated the effect of triterpenes on octanoylated ghrelin production. Asiatic acid, corosolic acid, glycyrrhetinic acid, oleanolic acid and ursolic acid suppressed octanoylated ghrelin levels in AGS-GHRL8 cells without decreasing transcript expression of GOAT or furin, a protease required for ghrelin maturation. β-amyrin had no effect on octanoylated ghrelin level, which was only slightly inhibited by uvaol; the fact that both these triterpenes lack a carboxyl group indicates that this group is important for suppressing octanoylated ghrelin production. These results suggest that triterpenes may have the potential as obesity-preventing agents with suppressive effect on octanoylated ghrelin production.

  1. Strain uses gap junctions to reverse stimulation of osteoblast proliferation by osteocytes

    PubMed Central

    Suswillo, Rosemary F.L.; Rawlinson, Simon C.F.; Dowthwaite, Gary P.; Lanyon, Lance E.; Pitsillides, Andrew A.

    2017-01-01

    Identifying mechanisms by which cells of the osteoblastic lineage communicate in vivo is complicated by the mineralised matrix that encases osteocytes, and thus, vital mechanoadaptive processes used to achieve load‐bearing integrity remain unresolved. We have used the coculture of immunomagnetically purified osteocytes and primary osteoblasts from both embryonic chick long bone and calvariae to examine these mechanisms. We exploited the fact that purified osteocytes are postmitotic to examine both their effect on proliferation of primary osteoblasts and the role of gap junctions in such communication. We found that chick long bone osteocytes significantly increased basal proliferation of primary osteoblasts derived from an identical source (tibiotarsi). Using a gap junction inhibitor, 18β‐glycyrrhetinic acid, we also demonstrated that this osteocyte‐related increase in osteoblast proliferation was not reliant on functional gap junctions. In contrast, osteocytes purified from calvarial bone failed to modify basal proliferation of primary osteoblast, but long bone osteocytes preserved their proproliferative action upon calvarial‐derived primary osteoblasts. We also showed that coincubated purified osteocytes exerted a marked inhibitory action on mechanical strain–related increases in proliferation of primary osteoblasts and that this action was abrogated in the presence of a gap junction inhibitor. These data reveal regulatory differences between purified osteocytes derived from functionally distinct bones and provide evidence for 2 mechanisms by which purified osteocytes communicate with primary osteoblasts to coordinate their activity. PMID:28083967

  2. Lowering effect of phenolic glycosides on the rise in postprandial glucose in mice.

    PubMed

    Takii, H; Matsumoto, K; Kometani, T; Okada, S; Fushiki, T

    1997-09-01

    Glycosides were screened for their lowering effect on the postprandial blood glucose rise in vivo. The effect of phlorizin and other phenolic glycosides on the postprandial blood glucose response to glucose ingestion was evaluated in Std ddY mice. When phlorizin was simultaneously added, the peak blood glucose level was significantly decreased by 51% (p < 0.01) compared to vehicles following glucose ingestion by mice, while the blood insulin responses were generally similar. Screening experiments were conducted with different classes of phenolic glycosides added to a glucose solution. Reductions of 40-52% (p < 0.05) were observed in vehicles containing arbutin, 4-hydroxyphenyl-alpha-D-glucopyranoside (hydroquinone-alpha-glucoside) or glycyrrhizin, and of only 15-31% (not significant) in vehicles containing neohesperidin dihydrochalcone, glycyrrhetinic acid monoglucuronide, or 3,4-dimethoxyphenyl-beta-D-glucopyranoside. No lowering effect was observed in vehicles containing salicin. Since glycyrrhizin, arbutin, and hydroquinone-alpha-glucoside blunted to varying degrees the postprandial blood glucose rise following glucose ingestion, they may be useful adjuvants for the treatment of diabetic subjects.

  3. Treatment of pruritus in mild-to-moderate atopic dermatitis with a topical non-steroidal agent.

    PubMed

    Veraldi, Stefano; De Micheli, Paolo; Schianchi, Rossana; Lunardon, Luisa

    2009-06-01

    Atopiclair (Zarzenda) is a topical non-steroidal anti-inflammatory agent for the treatment of allergic diseases of the skin. Three main ingredients are contained in this product: glycyrrhetinic acid, telmesteine and Vitis vinifera extracts. Other ingredients include: allantoin, alpha-bisabolol, capryloyl glycine, hyaluronic acid, shea butter and tocopheryl acetate. Two previous randomized, double-blind, vehicle-controlled clinical studies provided evidence that Atopiclair is effective in the treatment of atopic dermatitis. This article presents an open, multicenter, sponsor-free, study on the anti-pruritic activity of this product in adult patients with mild-to-moderate atopic dermatitis. The Median Visual Analogue Scale (VAS) values were: at the start of the study (TO), median VAS was 48.5 mm; three weeks later (T1), median VAS was 34.1 mm (-14.4 mm from baseline); six weeks later (T2), median VAS was 24.6 mm (-23.9 mm from baseline). Statistical analysis revealed that differences between TO versus T1, TO versus T2 and T1 versus T2 were highly significant (p<0.001). Side effects (local burning) were relatively common, although mild in severity. On the basis of the results of this study, Atopiclair showed efficacy in relief of pruritus in adult patients with mild-to-moderate atopic dermatitis.

  4. Effects of Active Components of Fuzi and Gancao Compatibility on Bax, Bcl-2, and Caspase-3 in Chronic Heart Failure Rats

    PubMed Central

    Wang, Liqin; He, Yu; Zhang, Yuyan; Zhou, Huifen; Yu, Li

    2016-01-01

    Hypaconitine (HA) and glycyrrhetinic acid (GA) are active components of Fuzi (Aconitum carmichaelii) and Gancao (Glycyrrhiza uralensis Fisch); they have been used in compatibility for chronic heart failure (CHF) from ancient times. The purpose of the present research was to explore whether apoptosis pathways were related with the protective effects of HA + GA against CHF rats or not. The rats were progressed with transverse-aortic constriction (TAC) operation for 4 weeks to build the CHF state, and then the Digoxin (1 mg/kg), HA (2.07 mg/kg), GA (25 mg/kg), and HA (2.07 mg/kg) + GA (25 mg/kg) were orally administrated to rats for 1 week. The levels of BNP and cTnI in the plasma were decreased in the HA + GA group, and the heart/body weight ratio (H/B) and left ventricular (LV) parameters of transthoracic echocardiography were also declined; moreover, the expressions of Bax, Bcl-2, and caspase-3 were all improved in the HA + GA group than other groups in the immunohistochemistry and western blot methods. In general, the data suggested that Fuzi and Gancao compatibility could protect the CHF rats from apoptosis, which provided a strong evidence for further searching for mechanisms of them. PMID:28053643

  5. Physiological role of gap-junctional hemichannels. Extracellular calcium-dependent isosmotic volume regulation.

    PubMed

    Quist, A P; Rhee, S K; Lin, H; Lal, R

    2000-03-06

    Hemichannels in the overlapping regions of apposing cells plasma membranes join to form gap junctions and provide an intercellular communication pathway. Hemichannels are also present in the nonjunctional regions of individual cells and their activity is gated by several agents, including calcium. However, their physiological roles are unknown. Using techniques of atomic force microscopy (AFM), fluorescent dye uptake assay, and laser confocal immunofluorescence imaging, we have examined the extracellular calcium-dependent modulation of cell volume. In response to a change in the extracellular physiological calcium concentration (1.8 to glycyrrhetinic acid, or were reversed by returning extracellular calcium to the normal level. We conclude that nongap-junctional hemichannels regulate cell volume in response to the change in extracellular physiological calcium in an otherwise isosmotic situation.

  6. Shieldable tumor targeting based on pH responsive self-assembly/disassembly of gold nanoparticles.

    PubMed

    Tian, Zhiqing; Yang, Chengling; Wang, Wei; Yuan, Zhi

    2014-10-22

    A new approach to shield/deshield ligands for controllable tumor targeting was reported, which was based on amphiphilic self-assembly and disassembly of gold nanoparticles (Au NPs). Thanks to the excellent pH response of the system, glycyrrhetinic acid (GA) ligands can be buried inside the Au NPs' assembly at normal tissue pH (pH 7.4), while exposed when the nanostructure is disassembled at tumor extracellular pH (pHe 6.8). Hydrophobic GA molecules not only acted as ligands targeting tumor cells but also provided the major interparticle attractive force for Au NPs' assembling. An ordered assembly of Au NPs with regular shape, proper size and ultrasharp pH sensitivity (ΔpH ∼ 0.2) was achieved by fine-tuning of materials modified on Au NPs. Mechanism studies for assembly and disassembly of Au NPs indicated the possibility of a GA shield when the assembly formed, which was further demonstrated by bovine serum albumin absorption and cellular uptake. The assembly/disassembly process was reversible within extrinsic pH changes, which provides a perspective for reversible tumor targeting.

  7. Hemichannels formed by connexin 43 play an important role in the release of prostaglandin E(2) by osteocytes in response to mechanical strain.

    PubMed

    Jiang, Jean X; Cherian, Priscilla P

    2003-01-01

    Osteocytes embedded in the matrix of bone are mechanosensory cells that translate strain into signals and regulate bone remodeling. Our previous studies using osteocyte-like MLO-Y4 cells have shown that fluid flow shear stress (FFSS) increases connexin (Cx) 43 protein expression, prostaglandin E(2) (PGE(2)) release, and intercellular coupling, and PGE(2) is an essential mediator between FFSS and gap junctions. However, the role of Cx43 in the release of PGE(2) in response to FFSS is unknown. Here, the FFSS-loaded MLO-Y4 cells with no or few intercellular channels released significantly more PGE(2) per cell than those cells at higher densities. Antisense Cx43 oligonucleotides and 18 beta-glycyrrhetinic acid, a specific gap junction and hemichannel blocker, significantly reduced PGE(2) release by FFSS at all cell densities tested, especially cells at the lowest density without gap junctions. FFSS, fluid flow-conditioned medium, and PGE(2) increased the activity of dye uptake. Moreover, FFSS induced Cx43 to migrate to the surface of the cell; this surface expressed Cx43 developed resistance to Triton-X-100 solublization. Our results suggest that hemichannels formed by Cx43, instead of intercellular channels, are likely to play a predominant role in the release of intracellular PGE(2) in response to FFSS.

  8. Mechanical signaling coordinates the embryonic heartbeat

    PubMed Central

    Chiou, Kevin K.; Rocks, Jason W.; Chen, Christina Yingxian; Cho, Sangkyun; Merkus, Koen E.; Rajaratnam, Anjali; Robison, Patrick; Tewari, Manorama; Vogel, Kenneth; Majkut, Stephanie F.; Prosser, Benjamin L.; Discher, Dennis E.; Liu, Andrea J.

    2016-01-01

    In the beating heart, cardiac myocytes (CMs) contract in a coordinated fashion, generating contractile wave fronts that propagate through the heart with each beat. Coordinating this wave front requires fast and robust signaling mechanisms between CMs. The primary signaling mechanism has long been identified as electrical: gap junctions conduct ions between CMs, triggering membrane depolarization, intracellular calcium release, and actomyosin contraction. In contrast, we propose here that, in the early embryonic heart tube, the signaling mechanism coordinating beats is mechanical rather than electrical. We present a simple biophysical model in which CMs are mechanically excitable inclusions embedded within the extracellular matrix (ECM), modeled as an elastic-fluid biphasic material. Our model predicts strong stiffness dependence in both the heartbeat velocity and strain in isolated hearts, as well as the strain for a hydrogel-cultured CM, in quantitative agreement with recent experiments. We challenge our model with experiments disrupting electrical conduction by perfusing intact adult and embryonic hearts with a gap junction blocker, β-glycyrrhetinic acid (BGA). We find this treatment causes rapid failure in adult hearts but not embryonic hearts—consistent with our hypothesis. Last, our model predicts a minimum matrix stiffness necessary to propagate a mechanically coordinated wave front. The predicted value is in accord with our stiffness measurements at the onset of beating, suggesting that mechanical signaling may initiate the very first heartbeats. PMID:27457951

  9. Cardiovascular action of a new carbenoxolone derivative.

    PubMed

    Filczewski, M; Kosmala, M; Oledzka, K

    1988-01-01

    The circulatory effects of oleanoic acid sodium hydrogen succinate (OSS), an analogue of the anti-ulcer drug, carbenoxolone, were investigated. As carbenoxolone produces such adverse effects as sodium retention and a subsequent elevation of the arterial blood pressure in man, the present study was aimed at determining whether OSS is similar or different from it in this respect. Carbenoxolone, (43,3 mg/kg po) and OSS (66,6 mg/kg po) were given to rats twice daily for 4 weeks. The systolic blood pressure was elevated already after the first week of treatment. The hypertension was accompanied by bradycardia, which increased with the time of treatment. In the blood an increase in the creatinine level, a decrease in the urea level, and a slight elevation in sodium concentration were found after the treatment, while the potassium concentration during the whole treatment period (4 weeks) remained unchanged. Although the principal aldosterone-like effects of carbenoxolone were attributed to the oxygen presence in position 11 of the glycyrrhetinic acid ring, [8], the absence of an oxygen at that position in OSS did not cause the loss of the adverse circulatory effect.

  10. Self-assembly of renewable  nano-sized triterpenoids.

    PubMed

    Bag, Braja Gopal; Majumdar, Rakhi

    2017-02-14

    Studies on plant metabolites have gained renewed interest in recent years because these can serve as renewable chemicals for the development of a sustainable society. Among various plant secondary metabolites, terpenoids constitute the major component and triterpenoids are the 30C subset of it. In recent years, triterpenoids have drawn the attention of scientific community due to many of its potential and realized applications in medicine, drug delivery, thermochromic materials, pollutant capture, catalysis, liquid crystals, etc. In this personal review, we have discussed our computational results carried out on sixty representative naturally occurring triterpenoids demonstrating that all the triterpenoids are renewable functional nano-entities. Study of the self-assembly of several triterpenoids such as betulin, betulinic acid, oleanolic acid, glycyrrhetinic acid and arjunolic acid and their derivatives in different liquids have also been discussed. Moreover, the utilization of the resulting supramolecular architectures such as vesicles, spheres, flowers and fibrillar networks of nano- to micrometer dimensions and gels have also been discussed in the perspective of green, renewable and nanos.

  11. Simultaneous determination of oleanolic acid, p-coumaric acid, ferulic acid, kaemperol and quercetin in rat plasma by LC-MS-MS and application to a pharmacokinetic study of Oldenlandia diffusa extract in rats.

    PubMed

    Li, Neng; Liu, Changhui; Mi, Suiqing; Wang, Ningsheng; Zheng, Xia; Li, Yingyi; Huang, Xiaotao; He, Shaoling; Chen, Hao; Xu, Xinhua

    2012-01-01

    A simple, rapid and sensitive liquid chromatography tandem mass spectrometry method is presented for the simultaneous determination of oleanolic acid, p-coumaric acid, ferulic acid, kaemperol and quercetin in rat plasma. Glycyrrhetinic acid was used as an internal standard, and sample pretreatment consisted of a liquid-liquid extraction. Chromatographic separation was achieved on a Gemini 110A C18 column (50 × 2.0 mm i.d., 5 µm) by gradient elution with a mobile phase consisting of methanol, acetonitrile and 0.01% formic acid in water. Tandem mass spectrometric detection was conducted using multiple reaction monitoring under negative ionization mode. Calibration curves offered linear ranges of two orders of magnitude with r > 0.99. The method was validated in terms of matrix effect, intra-day and inter-day precision, accuracy, linearity, specificity and stability. The relative standard deviation of intra-day and inter-day variations ranged from 2.66 to 14.74% and 1.9 to 14.55%. No substantial endogenous interference from blank plasma was observed. The method has been successfully applied to a pharmacokinetic study of Oldenlandia diffusa extract after oral administration in rats.

  12. A selective HPLC method for determination of lercanidipine in tablets.

    PubMed

    Alvarez-Lueje, A; Pujol, S; Squella, J A; Núñez-Vergara, L J

    2003-02-05

    An HPLC reversed phase method using both UV (356 nm) and electrochemical (1000 mV) detection was developed in order to determine lercanidipine in commercial tablets. Repeatability and reproducibility were adequate. For quantification we have used the calibration plot method for lercanidipine concentration ranging between 1 x 10(-5) and 1 x 10(-4) M. Also, the proposed method is sufficiently selective to distinguish the parent drug and the degradation products after hydrolysis, photolysis or chemical oxidation. Furthermore, the typical excipients included in the drug formulation (talc, lactose, cornstarch, microcrystalline cellulose, carboxymethylcellulose and magnesium stearate) do not interfere with the selectivity of the method. Finally, the proposed chromatographic method was successfully applied to the quantitative determination of lercanidipine in commercial tablets.

  13. Differential scanning calorimetry to investigate the compatibility of ciprofloxacin hydrochloride with excipients.

    PubMed

    Fathy, M; Hassan, M A; Mohamed, F A

    2002-12-01

    The compatibility between ciprofloxacin hydrochloride (CFX) and some excipients was evaluated using differential scanning calorimetry (DSC). Physical mixture, coground mixture, compressed mixture and kneaded mixture were prepared to study the effect of sample manipulation. In addition, the samples of physical mixture were also accelerated at 55 degrees C for three weeks to obtain more reliable conclusions. Different types of excipients currently used in tablet or capsule formulations namely, calcium phosphate dibasic dihydrate (Emcompress), magnesium stearate lactose, sorbitol, mannitol, croscarmellose sodium (Ac-Di-Sol), sodium carboxymethyl starch (Primojel), microcrystalline cellulose (Avicel PH 101, Emcocil) were examined. The DSC scan of CFX displayed two endothermic peaks probably as a result of a fusion process followed by a decomposition process. CFX appeared to interact with sorbitol, mannitol, Ac-Di-Sol, Primojel, Avicel PH 101 and Emcocil.

  14. Polarization dependence of Raman scattering from a thin film involving optical anisotropy theorized for molecular orientation analysis.

    PubMed

    Itoh, Yuki; Hasegawa, Takeshi

    2012-06-14

    Polarized Raman scattering from a thin film involving uniaxial optical anisotropy deposited on a dielectric substrate has analytically been theorized. The analyte film is modeled as a three-phase system (air/film/substrate) to calculate the electromagnetic fields of the incident and scattered light propagating across the system with an aid of the transfer matrix method to exactly take the optical anisotropy of the film into account. On the new theory, a methodology for molecular orientation analysis of an extended polymethylene chain in the film is proposed, which is employed for determination of the tilt angles of the chains in single- and five-monolayer Langmuir-Blodgett (LB) films of cadmium stearate deposited on a glass plate. The results agree well with those obtained by infrared spectroscopy, which confirms reliability of the present method.

  15. The effect of different soft segments on the formation and properties of binary core microencapsulated phase change materials with polyurea/polyurethane double shell.

    PubMed

    Ma, Yanhong; Chu, Xiaodong; Tang, Guoyi; Yao, Youwei

    2013-02-15

    A series of polyurea/polyurethane microcapsules with butyl stearate and paraffin as binary core materials are successfully synthesized via interfacial polymerization method. The phase change temperature of these microencapsulated phase change materials (micro-PCMs) can be adjusted by regulating the composition of the binary core. SEM photographs show that these micro-PCMs have relatively spherical profiles and compact surfaces with diameter ranging from 5 to 15 μm. DSC results indicate that the binary core content in micro-PCMs is in a range of 45-60 wt%. Moreover, after being treated under 50°C for 7 days or subjected to thermal-cycling test for 500 times, the micro-PCMs keep good thermal performances and stabilities. Besides, these micro-PCMs show good thermal stability, and the degradation temperature differs from the different compositions of the binary core and molecular weight of the water-soluble monomers.

  16. Non-destructive determination of metronidazole powder by using artificial neural networks on short-wavelength NIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhao, Lingzhi; Dou, Ying; Mi, Hong; Ren, Meiyan; Ren, Yulin

    2007-04-01

    The present study aimed at providing a new method in sight into short-wavelength near-infrared (NIR) spectroscopy of in pharmaceutical quantitative analysis. To do that, 124 experimental samples of metronidazole powder were analyzed using artificial neural networks (ANNs) in the 780-1100 nm region of short-wavelength NIR spectra. In this paper, metronidazole was as active component and other two components (magnesium stearate and starch) were as excipients. Different preprocessing spectral data (first-derivative, second-derivative, standard normal variate (SNV) and multiplicative scatter correction (MSC)) were applied to establish the ANNs models of metronidazole powder. The degree of approximation, a new evaluation criterion of the networks was employed to prove the accuracy of the predicted results. The results presented here demonstrate that the short-wavelength NIR region is promising for the fast and reliable determination of major component in pharmaceutical analysis.

  17. Compatibility study of paracetamol, chlorpheniramine maleate and phenylephrine hydrochloride in physical mixtures.

    PubMed

    de Oliveira, G G G; Feitosa, A; Loureiro, K; Fernandes, A R; Souto, E B; Severino, P

    2017-01-01

    Paracetamol (PAR), phenylephrine hydrochloride (PHE) and chlorpheniramine maleate (CPM) are commonly used in clinical practice as antipyretic and analgesic drugs to ameliorate pain and fever in cold and flu conditions. The present work describes the use of thermal analysis for the characterization of the physicochemical compatibility between drugs and excipients during the development of solid dosage forms. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to study the thermal stability of the drug and of the physical mixture (drug/excipients) in solid binary mixtures (1:1). DSC thermograms demonstrated reproducible melting event of the prepared physical mixture. Starch, mannitol, lactose and magnesium stearate influence thermal parameters. Information recorded from the derivative thermogravimetric (DTG) and TGA curves demonstrated the decomposition of drugs in well-defined thermal events, translating the suitability of these techniques for the characterization of the drug/excipients interactions.

  18. One-pot process combining transesterification and selective hydrogenation for biodiesel production from starting material of high degree of unsaturation.

    PubMed

    Yang, Ru; Su, Mengxing; Li, Min; Zhang, Jianchun; Hao, Xinmin; Zhang, Hua

    2010-08-01

    A one-pot process combining transesterification and selective hydrogenation was established to produce biodiesel from hemp (Cannabis sativa L.) seed oil which is eliminated as a potential feedstock by a specification of iodine value (IV; 120 g I(2)/100g maximum) contained in EN 14214. A series of alkaline earth metal oxides and alkaline earth metal supported copper oxide were prepared and tested as catalysts. SrO supported 10 wt.% CuO showed the superior catalytic activity for transesterification with a biodiesel yield of 96% and hydrogenation with a reduced iodine value of 113 and also exhibited a promising selectivity for eliminating methyl linolenate and increasing methyl oleate without rising methyl stearate in the selective hydrogenation. The fuel properties of the selective hydrogenated methyl esters are within biodiesel specifications. Furthermore, cetane numbers and iodine values were well correlated with the compositions of the hydrogenated methyl esters according to degrees of unsaturation. (c) 2010 Elsevier Ltd. All rights reserved.

  19. Electrochemistry in vivo: monitoring dopamine release in the brain of the conscious, freely moving rat.

    PubMed

    Lane, R F; Blaha, C D; Hari, S P

    1987-07-01

    Changes in electrochemical responses at stearate-modified and unmodified graphite paste electrodes were compared simultaneously by intrastriatal chronoamperometry in freely moving rats. Responses at the modified electrodes were unaffected by ascorbate administration, decreased by pergolide and increased by pargyline and haloperidol. The effects of haloperidol were reversed by gamma-butyrolactone but not by pargyline. In contrast, responses at the unmodified electrodes were increased by ascorbate or pergolide and decreased by pargyline. Haloperidol-induced increases at these electrodes were rapidly reversed by pargyline. Responses of the two electrodes differed significantly in both magnitude and temporal characteristics after amphetamine administration. The results demonstrate that the modified electrodes can selectively monitor released dopamine in the freely moving animal, even when there are simultaneous, large changes in ascorbate and 3,4-dihydroxyphenylacetic acid.

  20. Recent Advances in Detailed Chemical Kinetic Models for Large Hydrocarbon and Biodiesel Transportation Fuels

    SciTech Connect

    Westbrook, C K; Pitz, W J; Curran, H J; Herbinet, O; Mehl, M

    2009-03-30

    n-Hexadecane and 2,2,4,4,6,8,8-heptamethylnonane represent the primary reference fuels for diesel that are used to determine cetane number, a measure of the ignition property of diesel fuel. With the development of chemical kinetics models for these two primary reference fuels for diesel, a new capability is now available to model diesel fuel ignition. Also, we have developed chemical kinetic models for a whole series of large n-alkanes and a large iso-alkane to represent these chemical classes in fuel surrogates for conventional and future fuels. Methyl decanoate and methyl stearate are large methyl esters that are closely related to biodiesel fuels, and kinetic models for these molecules have also been developed. These chemical kinetic models are used to predict the effect of the fuel molecule size and structure on ignition characteristics under conditions found in internal combustion engines.

  1. The Prevention of the Ice Hazard on Airplanes

    NASA Technical Reports Server (NTRS)

    Geer, William C; Scott, Merit

    1930-01-01

    A review of various methods to prevent ice formation and adhesion to aircraft surfaces is given. It was concluded that the adhesion of ice to a surface may be reduced somewhat by the application of certain waxes and varnishes. In the experiments described, the varnishes containing calcium stearate and calcium oleate gave the best results. In wind tunnel tests, the adhesion was further reduced by the application of these waxes and varnishes to a thin, heat insulating layer of rubber. The adhesion of ice is greatly reduced when the surface consists of a vehicle which carries an oil in sufficient quantity so that the surface of the vehicle is self lubricating. Ice may be removed from wings, struts, wires and other parts of an airplane during flight by the inflation of properly constructed pneumatic rubber members, providing that these members have been previously treated with a suitable low adhesion oil.

  2. Design of Peumus boldus tablets by direct compression using a novel dry plant extract.

    PubMed

    Palma, Santiago; Luján, Claudia; Llabot, Juan Manuel; Barboza, Gloria; Manzo, Ruben Hilario; Allemandi, Daniel Alberto

    2002-02-21

    A solid pharmaceutical dosage formulation using a novel dry plant extract of Peumus boldus MOL. (Monimiaceae) (Pb) is proposed. The botanical evaluation of plant material, through morphological and anatomical diagnosis, is presented. This evaluation permits to identify the herb to be used correctly. The analysis of the most extractive solvent mixture and the attainment of plant extract (fluid and dry) are reported. Several formulations (tablets) containing a novel dry plant extract of Pb and common excipients for direct compression are evaluated. The following formulation: dry plant extract of Pb (170 mg), Avicel PH101 (112 mg), Lactose CD (112) and magnesium stearate (6 mg), compressed at 1000 mPa, showed the best pharmaceutical performance.

  3. [XANES study of lead speciation in duckweed].

    PubMed

    Chu, Bin-Bin; Luo, Li-Qiang; Xu, Tao; Yuan, Jing; Sun, Jian-Ling; Zeng, Yuan; Ma, Yan-Hong; Yi, Shan

    2012-07-01

    Qixiashan lead-zinc mine of Nanjing was one of the largest lead zinc deposits in East China Its exploitation has been over 50 years, and the environmental pollution has also been increasing. The lead concentration in the local environment was high, but lead migration and toxic mechanism has not been clear. Therefore, biogeochemistry research of the lead zinc mine was carried out. Using ICP-MS and Pb-L III edge XANES, lead concentration and speciation were analyzed respectively, and duckweed which can tolerate and enriched heavy metals was found in the pollution area. The results showed that the lead concentration of duckweed was 39.4 mg x kg(-1). XANES analysis and linear combination fit indicated that lead stearate and lead sulfide accounted for 65% and 36.9% respectively in the lead speciation of duckweed, suggesting that the main lead speciation of duckweed was sulfur-containing lead-organic acid.

  4. Self-assembled biomimetic superhydrophobic CaCO3 coating inspired from fouling mineralization in geothermal water.

    PubMed

    Wang, Gong G; Zhu, Li Q; Liu, Hui C; Li, Wei P

    2011-10-18

    Inspired from fouling self-mineralization in geothermal water, a novel biomimetic cactuslike CaCO(3) coating with superhydrophobic features is reported in this letter. The structure, morphologies, and phases of the CaCO(3) coating were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, and infrared spectrophotometry. After prenucleation treatment, a continuous cactuslike CaCO(3) coating with hierarchical nano- and microstructures was self-assembled on stainless steel surfaces after immersion in simulated geothermal water at 50 °C for 48 h. After being modified with a low-surface-energy monolayer of sodium stearate, the as-prepared coating exhibited superhydrophobic properties with a water contact angle of 158.9° and a sliding angle of 2°. Therefore, this work might open up a new application field of geothermal resources and provide insight into designing multidimensional structures with functional applications, including superhydrophobic surfaces. © 2011 American Chemical Society

  5. Experimental analysis of the thermodynamic mechanism of Langmuir-Blodgett film transfer

    SciTech Connect

    Egusa, Syun; Gemma, Nobuhiro, Azuma, Makoto )

    1990-03-22

    An experimental investigation was made on the mechanism for the transfer of a Langmuir-Blodgett (LB) film. The transfer ratio ({rho}) and the interfacial force (f) were observed for stearyl alcohol and cadmium stearate monolayers on silicon substrates, by systematically varying both the surface pressures ({pi}) of the monolayer and the hydrophilicities of the substrate characterized by contact angle ({theta}{sub 0}). It was found that the ratios {rho} observed both for up- and down-stroke depositions changed discretely within zero and unity, divided at the critical values of {pi} and {theta}{sub 0}. To examine the film-transfer characteristics, on the basis of thermodynamics, the interfacial forces applied to the moving substrate were measured during the deposition process.

  6. Dramatic enhancement of capillary wave fluctuations of a decorated water surface

    SciTech Connect

    Datta, A.; Kundu, S.; Sanyal, M.K.; Daillant, J.; Luzet, D.; Blot, C.; Struth, B.

    2005-04-01

    We have demonstrated by x-ray diffuse scattering that a bimolecular layer of a preformed three-tailed amphiphile, ferric stearate, drastically enhances capillary wave fluctuations on water surface due to a reduction in surface tension to 1 mN/m. The bimolecular layer is composed of molecules in symmetric configuration, on top of molecules in asymmetric configuration with ferric ions in contact with water. Unlike the usual Langmuir monolayers, this layer of molecules does not rupture under compression, but becomes thicker. This behavior mimics folding of a membrane on a liquid surface and is closely related to the cohesive interaction brought by the ferric ions. The low effective tension of this artificial membrane depends on the available area and reduces as the microscopic excess area increases.

  7. Free-choice-profile descriptive analysis of sticks with conditioning agents.

    PubMed

    Gámbaro, Adriana; Parente, María Emma; Giménez, Ana

    2006-01-01

    Nine formulations to be used as stick bases were manufactured using sodium stearate, propyleneglycol, and water, adding different concentrations of the following conditioning agents: octyldodecanol, PPG-5-ceteth-20, and PPG-15-stearyl ether. Free-choice-profile methodology was used to select the most adequate concentration of the agents in order to improve sensory properties. The sensory descriptors were grouped into four categories: stick aspect, sensations during application, sensations immediately after application, and sensations five minutes after application. Formulations containing 4% and 6% octyldodecanol and 2% PPG-15-stearyl ether were considered inadequate, since they showed unwanted qualities such as exudation, a slow absorption rate, high oiliness, and residue. Formulations containing 2% octyldodecanol; 2%, 4%, and 6% PPG-5-ceteth-20; and 4% and 6% PPG-15-stearyl ether presented different characteristics regarding the four categories of descriptors evaluated, all of them being acceptable considering the properties sought.

  8. Disposal of Pyrotechnic Illuminating and Signalling Ammunition

    DTIC Science & Technology

    2000-04-01

    Mg Stearate 2 % [Mg(C 1 8H350 2)] Varnish 8 % [C 16 H 2 6 0 2] Mg 29 % Composition ,,red" KNo 3 14% SrNo 3 40 % PVC 10% [(C2H3Cl)n] Varnish 7...Mg 40 % Composition ,,green" Ba(No 3)2 40 % PVC 15 % Varnish 5 % There are also the following combustible compositions in form of black powder: KNo 3...130 4700 6900 7400 Nitrate mg/i 0.85 8.5 < 0.1 1.6 5.4 Nitrite mg/i < 0.2 9.8 < 0.2 0.25 < 0.2 Sulphate mg/i 131 282 < 0.5 < 0.5 630 Fluoride mg/i 0.1

  9. Mononuclear phagocyte accumulates a stearic acid derivative during differentiation into macrophages. Effects of stearic acid on macrophage differentiation and Mycobacterium tuberculosis control.

    PubMed

    Mosquera-Restrepo, Sergio Fabián; Caro, Ana Cecilia; Peláez-Jaramillo, Carlos Alberto; Rojas, Mauricio

    2016-05-01

    The fatty acid composition of monocytes changes substantially during differentiation into macrophages, increasing the proportion of saturated fatty acids. These changes prompted us to investigate whether fatty acid accumulation in the extracellular milieu could affect the differentiation of bystander mononuclear phagocytes. An esterified fatty acid derivative, stearate, was the only fatty acid that significantly increased in macrophage supernatants, and there were higher levels when cells differentiated in the presence of Mycobacterium tuberculosis H37Rv or purified protein derivative (PPD). Exogenous stearic acid enhanced the expression of HLA-DR and CD64; there was also accumulation of IL-12, TNF-α, IL-6, MIP-1 α and β and a reduction in MCP-1 and the bacterial load. These results suggested that during differentiation, a derivative of stearic acid, which promotes the process as well as the effector mechanisms of phagocytes against the mycobacterium, accumulates in the cell supernatants.

  10. Facile synthesis of monodisperse ZnS capped CdS nanocrystals exhibiting efficient blue emission

    PubMed Central

    Protière, Myriam

    2006-01-01

    A new method for the capping of colloidal CdS nanocrystals with ZnS shells is presented. A combination of the monomolecular precursor zinc ethylxanthate (Zn(ex)2) and zinc stearate was used to replace hazardous organometallic reagents usually applied in this procedure, i.e. bis(trimethylsilyl) sulfide and diethylzinc. Its simple preparation, air-stability and low decomposition temperature of 150 °C make Zn(ex)2a very suitable source for the ZnS shell growth. With this precursor, highly luminescent CdS/ZnS core/shell nanocrystals (Q.Y. 35–45%), exhibiting narrow emission linewidths of 15–18 nm (FWHM) in the blue spectral region, can reproducibly be obtained.

  11. Influence of Avicel PH-301 on the compressibility of alpha-methyldopa and phenobarbitone in direct compression.

    PubMed

    Siaan, M; Pintye-Hódi, K; Szabó-Révész, P; Kása, P; Erõs, I

    2000-09-01

    The aim of this work was to investigate the compressibility behavior of alpha-methyldopa and phenobarbitone using a Korsch EK0 instrumented eccentric tablet machine, with force-time and force-displacement curves constructed and applied to calculate different compressional values to study the compressional behavior. The results of this work revealed a difference in compressibility behavior between the two drugs during the compressional process. alpha-Methyldopa gave an abnormal compressional curve with high friction in the pre- and postcompressional phases. A residual force could be seen on the lower punch. Furthermore, capping and sticking were observed visually during tablet pressing, indicating poor compressibility behavior. In the case of phenobarbitone, no friction was observed in the precompressional phase, but there was higher friction in the postcompressional phase, especially in the ejection phase. The compressibility of the drugs was improved by the addition of Avicel PH-301 and magnesium stearate.

  12. Environmental assessment of lubricants before and after wire drawing process.

    PubMed

    Ruiz, M C; Verde, J; Andrés, A; Viguri, J; Irabien, A

    2001-08-17

    Iron wire drawing processes involve the use of solid lubricants made of powdered raw materials, which lead to industrial wastes after being used. These wastes, based on stearates, have a negative effect on the environment. This study deals with the environmental assessment of some lubricants before and after the wire drawing process in a Spanish factory. The parameters evaluated for this study have been total organic carbon (TOC), mobility of zinc and lead, and ecotoxicity (EC(50)). Results show that wastes have more ecotoxicity than the original lubricants due to the content of metals that lubricants pick up from the wire, as pickling, patenting and galvanising take part in the manufacture. The capture of metallic particles leads to a reduction of TOC and an increase in ecotoxicity.

  13. Biochemistry of high stearic sunflower, a new source of saturated fats.

    PubMed

    Salas, Joaquín J; Martínez-Force, Enrique; Harwood, John L; Venegas-Calerón, Mónica; Aznar-Moreno, Jose Antonio; Moreno-Pérez, Antonio J; Ruíz-López, Noemí; Serrano-Vega, María J; Graham, Ian A; Mullen, Robert T; Garcés, Rafael

    2014-07-01

    Fats based on stearic acid could be a healthier alternative to existing oils especially hydrogenated fractions of oils or palm, but only a few non-tropical species produce oils with these characteristics. In this regard, newly developed high stearic oil seed crops could be a future source of fats and hard stocks rich in stearic and oleic fatty acids. These oil crops have been obtained either by breeding and mutagenesis or by suppression of desaturases using RNA interference. The present review depicts the molecular and biochemical bases for the accumulation of stearic acid in sunflower. Moreover, aspects limiting the accumulation of stearate in the seeds of this species are reviewed. This included data obtained from the characterization of genes and enzymes related to fatty acid biosynthesis and triacylglycerol assembly. Future improvements and uses of these oils are also discussed.

  14. The interaction of a binary/ternary interactive mixture of hydrophobic-hydrophilic materials on the drug distribution and drug release performance in the tablet formulation

    NASA Astrophysics Data System (ADS)

    Ainurofiq, A.; Choiri, S.

    2017-02-01

    The aim of this research was to optimize and determine an interaction of a binary/ternary mixture of hydrophobic-hydrophilic materials (H-HM) on the drug distribution, tablet characteristics, and drug release performance. The interactive mixture (IM) between carrier and H-HM was conducted using a carrier, Pruv and Cab-O-Sil as hydrophilic materials, magnesium stearate as a hydrophobic material, and a micronized nifedipine as a drug model. These interactions between binary and ternary mixtures of H-HM were assessed by a simplex centroid design (SCD) approach. The homogeneity of IM between drug and carrier was achieved at more time of mixing time. Unique effects and interactions of H-HM were observed on the drug distribution and drug release. Furthermore, the SCD had successfully determined the optimum design space of IM in the ternary mixture of H-HM.

  15. Gas chromatography with tandem differential mobility spectrometry of fatty acid alkyl esters and the selective detection of methyl linolenate in biodiesels by dual-stage ion filtering.

    PubMed

    Pasupuleti, D; Pierce, K; Eiceman, G A

    2015-11-20

    Alkyl esters of fatty acids (FAAEs) with carbon numbers from 8 to 20 formed protonated monomers and proton bound dimers through atmospheric pressure chemical ionization reactions and these gas ions were characterized for their field dependent mobility coefficients using differential mobility spectrometry (DMS). Separation of ion peaks with a vapor modifier was achieved for ions with masses of 317-1033 Da though the differences in these coefficients and the resolution of ion peaks decreased proportionally with increased ion mass. Differences in dispersion curves were sufficient to isolate ions from specific FAAEs in the effluent of a gas chromatograph by dual stage ion filtering using a tandem DMS detector. Methyl linolenate was isolated from nearby eluting methyl oleate, methyl stearate and methyl linoleate within analysis times of 10s without measureable complications from charge suppression in the ion source or leakage in filtering of ions with close proximity of dispersion behavior.

  16. Phytochemistry and medicinal properties of Phaleria macrocarpa (Scheff.) Boerl. extracts

    PubMed Central

    Altaf, Rabia; Asmawi, Mohammad Zaini Bin; Dewa, Aidiahmad; Sadikun, Amirin; Umar, Muhammad Ihtisham

    2013-01-01

    Phaleria macrocarpa, commonly known as Mahkota dewa is a medicinal plant that is indigenous to Indonesia and Malaysia. Extracts of P. macrocarpa have been used since years in traditional medicine that are evaluated scientifically as well. The extracts are reported for a number of valuable medicinal properties such as anti-cancer, anti-diabetic, anti-hyperlipidemic, anti-inflammatory, anti-bacterial, anti-fungal, anti-oxidant and vasorelaxant effect. The constituents isolated from different parts of P. macrocarpa include Phalerin, gallic acid, Icaricide C, magniferin, mahkoside A, dodecanoic acid, palmitic acid, des-acetylflavicordin-A, flavicordin-A, flavicordin-D, flavicordin-A glucoside, ethyl stearate, lignans, alkaloids andsaponins. The present review is an up-to-date summary of occurrence, botanical description, ethnopharmacology, bioactivity and toxicological studies related to P. macrocarpa. PMID:23922460

  17. In vitro release control of ketoprofen from pH-sensitive gels consisting of poly(acryloyl- L-proline methyl ester) and saturated fatty acid sodium salts

    NASA Astrophysics Data System (ADS)

    Negishi, M.; Hiroki, A.; Miyajima, M.; Yoshida, M.; Asano, M.; Katakai, R.

    1999-06-01

    The effect of saturated fatty acid sodium salts (C n), sodium laurate (C 12), sodium myristate (C 14), sodium palmitate (C 16), and sodium stearate (C 18), on the swelling of poly(acryloyl- L-proline methyl ester) (A-ProOMe) gel was investigated in different pH solutions. The C n-loaded gels collapsed in a buffer solution with pH 3.0, while they expanded in a buffer solution with pH 6.5. This effect was strongly influenced by the number of methylene units in C n, as the threshold for causing this sensitivity existed between C 12 and C 14. On the other hand, a pulsatile release of ketoprofen occurred when the gel was cycled in buffer solutions between pH 3.0 and pH 6.5. This behavior may be attributable to the surface-regulated mechanism.

  18. Electron paramagnetic resonance studies of membrane fluidity in ozone-treated erythrocytes and liposomes.

    PubMed

    Wróbel, A; Gomułkiewicz, J

    1999-01-01

    Doxyl stearate spin probes which differed in the attachment of the nitroxide free radical to the fatty acid have been used to study membrane fluidity in ozone-treated bovine erythrocytes and liposomes. Analysis of EPR spectra of spin labels incorporated into lipid bilayer of the erythrocyte membranes indicates an increase in the mobility and decrease in the order of membrane lipids. In isolated erythrocyte membranes (ghosts) the most significant changes were observed for 16-doxylstearic acid. In intact erythrocytes statistically significant were differences for 5-doxylstearic acid. The effect of ozone on liposomes prepared from a lipid extract of erythrocyte lipids was marked in the membrane microenvironment sampled by all spin probes. Ozone apparently leads to alterations of membrane dynamics and structure but does not cause increased rigidity of the membrane.

  19. Evaluation of selected micronized poloxamers as tablet lubricants.

    PubMed

    Desai, D; Zia, H; Quadir, A

    2007-10-01

    The primary objective of this study was to compare the lubrication properties of micronized poloxamer 188 (Lmicrotrol micro 68) and micronized poloxamer 407 (Lmicrotrol micro 127) with certain conventional lubricants such as magnesium stearate and stearic acid. The secondary objective was to use these micronized poloxamers as water-soluble tablet lubricants in preparation of effervecsent tablets. The results showed that these micronized poloxamers have superior lubrication properties compared with stearic acid, with no negative effect on tablet hardness, friability, disintegration, or dissolution. Moreover, lubricant mixing time had no significant effect on tablet properties when poloxamers were used as lubricants. Effervescent tablets also were produced successfully using micronized poloxamers as lubricants. The micronized poloxamers had a better lubrication effect in comparison with that of water-soluble lubricant l-leucine.

  20. Intrinsic adhesion force of lubricants to steel surface.

    PubMed

    Lee, Jonghwi

    2004-09-01

    The intrinsic adhesion forces of lubricants and other pharmaceutical materials to a steel surface were quantitatively compared using Atomic Force Microscopy (AFM). A steel sphere was attached to the tip of an AFM cantilever, and its adhesion forces to the substrate surfaces of magnesium stearate, sodium stearyl fumarate, lactose, 4-acetamidophenol, and naproxen were measured. Surface roughness varied by an order of magnitude among the materials. However, the results clearly showed that the two lubricants had about half the intrinsic adhesion force as lactose, 4-acetamidophenol, and naproxen. Differences in the intrinsic adhesion forces of the two lubricants were insignificant. The lubricant molecules were unable to cover the steel surface during AFM measurements. Intrinsic adhesion force can slightly be modified by surface treatment and compaction, and its tip-to-tip variation was not greater than its difference between lubricants and other pharmaceutical particles. This study provides a quantitative fundamental basis for understanding adhesion related issues.

  1. Agglomeration tendency in dry pharmaceutical granular systems.

    PubMed

    Lachiver, Emilie DesRosiers; Abatzoglou, Nicolas; Cartilier, Louis; Simard, Jean-Sébastien

    2006-10-01

    The agglomeration tendency of dry pharmaceutical mixtures containing various concentrations of Xylitab 100 (Xylitol), calcium carbonate precipitated (CCP) and magnesium stearate (MgSt) was evaluated statistically as a function of mixing time. A Ro-Tap tester was employed to mix the three pharmaceutical components, and the agglomerates formed were measured with respect to their weight and size. An experimental design was devised and applied to structure and then statistically analyze the results. Xylitab was found not to be influential in the formation of agglomerates, but aided in deagglomeration when mixed with other components. CCP and MgSt formed agglomerates over time and showed positive interactions favouring agglomeration. The agglomerates started to fracture when they reached a critical size, at which stage the particles' attraction forces (cohesion forces) were weaker than both gravity and inertia. It has been shown and quantitatively demonstrated that the mixing time and ingredient concentrations of a three-component pharmaceutical mixture can affect agglomeration tendency.

  2. Native starch in tablet formulations: properties on compaction.

    PubMed

    Bos, C E; Bolhuis, G K; Van Doorne, H; Lerk, C F

    1987-10-16

    Maize, potato, rice and tapioca (cassava) starch were evaluated with respect to their properties on direct compression. Rice starch showed much better compactibility as compared to maize, potato and tapioca starch. Moreover, its binding capacity proved to be almost insensitive to mixing with magnesium stearate. This in contrast to the dramatic decrease in crushing strength of potato starch tablets containing the lubricant. The compactibility of the starches was found to be strongly affected by the equilibrium moisture content of the starches, which is dependent on the relative humidity of the atmosphere under which the powders were stored. All starches showed adequate capacity for water uptake to act as a disintegrant. Rice starch exhibited worst flowability, caused by its fine particle size as compared to the other starches. Granulation of rice starch changed it into a potential filler-binder in tablets prepared by direct compression.

  3. A study of compressibility and compactibility of directly compressible tableting materials containing tramadol hydrochloride.

    PubMed

    Mužíková, Jitka; Kubíčková, Alena

    2016-09-01

    The paper evaluates and compares the compressibility and compactibility of directly compressible tableting materials for the preparation of hydrophilic gel matrix tablets containing tramadol hydrochloride and the coprocessed dry binders Prosolv® SMCC 90 and Disintequik™ MCC 25. The selected types of hypromellose are Methocel™ Premium K4M and Methocel™ Premium K100M in 30 and 50 % concentrations, the lubricant being magnesium stearate in a 1 % concentration. Compressibility is evaluated by means of the energy profile of compression process and compactibility by the tensile strength of tablets. The values of total energy of compression and plasticity were higher in the tableting materials containing Prosolv® SMCC 90 than in those containing Disintequik™ MCC 25. Tramadol slightly decreased the values of total energy of compression and plasticity. Tableting materials containing Prosolv® SMCC 90 yielded stronger tablets. Tramadol decreased the strength of tablets from both coprocessed dry binders.

  4. The physicochemical characterization and in vitro/in vivo evaluation of natural surfactants-based emulsions as vehicles for diclofenac diethylamine.

    PubMed

    Vucinić-Milanković, Nada; Savić, Snezana; Vuleta, Gordana; Vucinić, Slavica

    2007-03-01

    Two sugar-based emulsifiers, cetearyl alcohol & cetearyl glycoside and sorbitan stearate & sucrose cocoate, known as potential promoters of lamellar liquid crystals/gel phases, were investigated in order to formulate an optimal vehicle for amphiphilic drug - diclofenac diethylamine (DDA). Physico-chemical characterization and study of vehicle's physical stability were performed. Then, the in vitro DDA liberation profile, dependent on the mode of drug incorporation to the system, and the in vivo, short-term effects of chosen samples on skin parameters were examined. Droplets size distribution and rheological behavior indicated satisfying physical stability of both types of vehicles. Unexpectedly, the manner of DDA incorporation to the system had no significant influence on DDA release. In vivo study pointed to emulsion's favorable potential for skin hydration and barrier improvement, particularly in cetearyl glycoside-based vehicle.

  5. A novel fabrication of superhydrophobic surfaces for universal applicability

    NASA Astrophysics Data System (ADS)

    Chen, Su-Wen; Guo, Bo-Long; Wu, Wang-Suo

    2011-12-01

    The present work reports a novel and facile approach to fabricate stable superhydrophobic surfaces for universal applicability in practice. Poly(furfuryl alcohol)/copper composite coatings were prepared on substrates via a brush-painting method; after being immersed in a stearic acid solution, the superhydrophobic surfaces were obtained due to the formation of copper stearate on the substrates. These products were characterized by field-emission scanning electron microscopy, Fourier transform infrared spectrometry, X-ray powder diffraction and the X-ray photoelectron spectrum. Results demonstrate that the superhydrophobic surfaces formed originally on copper substrates can also be generated on other substrates without the copper element. Furthermore, this work will provide a simple and universal method to create large-scale superhydrophobic surfaces on various substrates.

  6. Application of waste bulk moulded composite (BMC) as a filler for isotactic polypropylene composites.

    PubMed

    Barczewski, Mateusz; Matykiewicz, Danuta; Andrzejewski, Jacek; Skórczewska, Katarzyna

    2016-05-01

    The aim of this study was to produce isotactic polypropylene based composites filled with waste thermosetting bulk moulded composite (BMC). The influence of BMC waste addition (5, 10, 20 wt%) on composites structure and properties was investigated. Moreover, additional studies of chemical treatment of the filler were prepared. Modification of BMC waste by calcium stearate (CaSt) powder allows to assess the possibility of the production of composites with better dispersion of the filler and more uniform properties. The mechanical, processing, and thermal properties, as well as structural investigations were examined by means of static tensile test, Dynstat impact strength test, differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), melt flow index (MFI) and scanning electron microscopy (SEM). Developed composites with different amounts of non-reactive filler exhibited satisfactory thermal and mechanical properties. Moreover, application of the low cost modifier (CaSt) allows to obtain composites with better dispersion of the filler and improved processability.

  7. Amlodipine besylate-excipients interaction in solid dosage form.

    PubMed

    Abdoh, A; Al-Omari, M M; Badwan, A A; Jaber, A M Y

    2004-01-01

    This article studies the compatibility of amlodipine besylate in its solid formulations with various drug excipients. The various factors affecting amlodipine besylate stability were studied using high-performance liquid chromatography (HPLC). It has been found that binary 1:1 mixtures of amlodipine besylate and an excipient are stable at 65 degrees C and 40 degrees C/75% RH. Further investigations were conducted to study the stability of amlodipine besylate in multicomponent mixtures, including mixtures with actual formulations. The study reveals that mixtures of lactose, magnesium stearate, and water induce some instability on amlodipine besylate. The major degradation product confirmed by HPLC-mass spectrometry is amlodipine besylate glycosyl. This is in conformity with the well-known Maillard reaction between primary amines and lactose. Thus, lactose-free amlodipine formulations are recommended from the safety, quality, efficacy, and process cost points of view.

  8. Influence of stearic acid on postprandial lipemia and hemostatic function.

    PubMed

    Sanders, Thomas A B; Berry, Sarah E E

    2005-12-01

    It has been suggested that fats rich in stearic acid may result in exaggerated postprandial lipemia and have adverse effects on hemostatic function. The effects of test meals containing different saturated and monounsaturated FA were compared in healthy subjects in a series of studies to investigate this hypothesis. Stearic acid, when present as cocoa butter, resulted in similar postprandial lipemia and factor VII activation compared with a meal containing high-oleic sunflower oil. Stearic acid when presented as shea butter or as randomized stearate-rich TAG resulted in decreased postprandial lipemia and decreased postprandial activation of factor VII. Stearic acid-rich test meals did not result in impaired fibrinolytic activity compared with either a low-fat meal or a meal high in oleate. The difference in responses between the different stearic acid-rich fats appears to be due to varying solid fat contents of the fats at 37 degrees C.

  9. Effect of Associative Polymers on the Foaming Properties of Surfactant Solutions

    NASA Astrophysics Data System (ADS)

    Cervantes, Alfredo; Robles, Emmanuel; Acuña, Heriberto; Gamez, Rogelio; Maldonado, Amir

    2006-03-01

    Aqueous foams are materials which have many industrial applications. Their stability is affected by three mechanisms: bubble coalescence (film rupture), coarsening (gas diffusion) and drainage (gravity-driven liquid flow). The aim of this work is to obtain some insight into the effect of associative polymers on the foamability, foam stability and drainage of surfactant solutions. The foams were produced by air bubbling and by the turbulent mixing method. The surfactant is SDS and the associative polymers studied are HEUR and POE-Stearate. We studied the effect of polymer concentration for each macromolecule. The results show that two opposite effects are present when the polymer concentration is increased: for low polymer concentrations, foamability and foam stability is higher than for high concentrations. Results are discussed in terms of the properties of the solution: surface tension, electrical conductivity, bulk viscosity, etc.

  10. Lyotropic mesophases formed by solutions of sodium strearate in glycerol and water

    NASA Astrophysics Data System (ADS)

    Wang, Qingbing; Joshi, Leela; Satyendra Kumar, Satyendra; Yaravoy, Yury; Teanoosh, Moaddel

    2004-03-01

    Solutions of sodium stearate in concentrations ranging from 1 to 20 wt %, in glycerol and glycerol + water exhibit two phases between room temperature and 100 °C for all mixtures. In the high temperature phase, the solutions flow easily while they form a gel phase with unique elastic properties in the low temperature phase. Small angle neutron and x-ray scattering measurements performed on partially deutrated samples reveal structural details of these solutions. The high temperature phase is found to be an isotropic dispersion of micellar aggregates, the lower temperature phase possesses more complex structure. These results augmented with results from differential scanning calorimetry, NMR proton relaxation and other techniques will be presented. Supported by Unilever Research, USA.

  11. Investigation and control of the uniformity of drug nanoparticles directly deposited on the particulate surfaces of excipient by PLD

    NASA Astrophysics Data System (ADS)

    Nagare, S.; Sagawa, Jo; Senna, M.

    2007-04-01

    Pulsed laser deposition (PLD) of drug nanoparticles for pharmaceutical preparation was investigated. Indomethacin (IM) was preliminary mixed with magnesium stearate (StMg) to prepare a target for PLD. By using the composite targets, the percentage of deposited nanoparticles in the collected powder increased compared to when only IM was ablated. The percentage of IM nanoparticles was the highest when IM and StMg were mixed at 1:1 ratio. Nanoparticles of the composite target were deposited on the micron sized particulate excipient, i.e., SiO2, potato starch, and lactose. The excipient powders were mixed by rotation. Their surface coverage was evaluated by FE-SEM observation and diffuse reflectance (DR) UV-Vis spectroscopy. The surface coverage was estimated to be around 50 % for 20 min deposition time. Simple rotation of the excipient powders was found to be one of the effective methods for uniform deposition of nanoparticles.

  12. A 4-week study of four 3-monochloropropane-1,2-diol diesters on lipid metabolism in C57BL/6J mice.

    PubMed

    Lu, Jing; Wang, Zhenning; Ren, Mengrou; Feng, Guangxin; Ye, Beining; Wang, Yi; Fang, Baochen; Deng, Xuming; Guan, Shuang

    2015-09-01

    3-Monochloropropane-1,2-diol (3-MCPD) esters have been detected in many foods, which have become a new safety issue worldwide. In the study, we investigated the effect of four 3-MCPD diesters (palmitate diester: CDP; stearate diester: CDS; oleate diester: CDO; linoleate diester: CDL) on lipid metabolism in C57BL/6J mice. The results showed that CDP, CDS, CDO and CDL significantly increased the serum TC, LDL-C levels and liver TG, TC levels at dose of 16.5μmol/kg/day. These results indicated that 3-MCPD diesters could potentially cause hyperlipidemia in C57BL/6J mice. Moreover, oil red O staining confirmed fat accumulation in liver induced by 3-MCPD diesters. Our work will provide more information for safety evaluation of 3-MCPD diesters. However, whether free 3-MCPD or free fatty acids or combined action compensates for the hyperlipidemia effects should be elucidated in the future.

  13. Erythromycin and lymecycline treatment in chlamydia-positive and Chlamydia-negative non-gonococcal urethritis--a partner-controlled study.

    PubMed

    Lassus, A; Paavonen, J; Kousa, M; Saikku, P

    1979-01-01

    A group of 213 men with non-gonococcal urethritis and their sexual partners were treated either with erythromycin stearate 500 mgx2 for 15 days or with lymecycline 300 mgx2 for 10 or 20 days. Chlamydia trachomatis was isolated from 40% of the men, from 26% of their female partners and from 56% of the partners of men with chlamydia-positive urethritis. One hundred and eighty-one men were available for evaluation of therapy. There were no significant differences between the treatment schedules. The cure rate was 86-90% in men with chlamydia-positive and 89-100% in men with chlamydia-negative urethritis. Four of the 17 chlamydia-positive females treated with erythromycin and 2 of the 20 chlamydia-positive females treated with lymecycline for 10 days still had chlamydia at re-examination.

  14. The majority of vitamin A is transported as retinyl esters in the blood of most carnivores.

    PubMed

    Schweigert, F J; Ryder, O A; Rambeck, W A; Zucker, H

    1990-01-01

    1. In canines and mustelides total vitamin A was 10-50 times higher compared to other species due to a high amount of retinyl esters (40-99% of total vitamin A) in blood plasma. The dominant vitamin A ester was in most species retinyl stearate. 2. In Ursidae, Procyonidae, Viveridae and Felidae, total vitamin A was much lower. When present, however, retinyl esters also represented 10-65% of total vitamin A in plasma. 3. Only retinol was detected in plasma of the family, Hyaenidae, and the suborder, Pinnipedia. 4. In maned wolf cubs it was found that retinol, retinyl esters and alpha-tocopherol increased with the age of the animals, reaching values comparable to adult animals at the age of 5 months.

  15. [A new water-soluble lubricant of tablets-L-leucine combined with PEG6000].

    PubMed

    Liu, Wei; Huang, Kai; Rao, Xiaoyong; Liu, Xiaoyan; Sun, Shasha; Luo, Xiaojian

    2011-08-01

    To prepare an effective and water-soluble lubricant. Co-sprayed lubricant (L-leucine and polyethylene glycol 6000 co-sprayed according to a certain proportion) and mixed lubricant (the physical mixture of spayed L-leucine and crushed polyethylene glycol 6000) were prepared and polyethylene glycol 6000, L-leucine, magnesium stearate, sodium stearyl fumarate and sodium chloride are crushed and sieved, respectively. Residual force, appearance of solution and disintegration time were considered as response variables of the lubrication effect to evaluate different lubricants. The changes of the co-sprayed lubricant were studied by differential scanning calorimetry, fourier infrared, electronic scanning microscope and X-ray diffraction. The efficacy of co-sprayed lubricant is better than other lubricants. Efficacy is improved by external form change without inner components and crystal changes. Co-sprayed lubricant is a good water soluble tablet lubricant which has good efficacy.

  16. [Determination of contact angle of pharmaceutical excipients and regulating effect of surfactants on their wettability].

    PubMed

    Hua, Dong-dong; Li, He-ran; Yang, Bai-xue; Song, Li-na; Liu, Tiao-tiao; Cong, Yu-tang; Li, San-ming

    2015-10-01

    To study the effects of surfactants on wettability of excipients, the contact angles of six types of surfactants on the surface of two common excipients and mixture of three surfactants with excipients were measured using hypsometry method. The results demonstrated that contact angle of water on the surface of excipients was associated with hydrophilcity of excipients. Contact angle was lowered with increase in hydrophilic groups of excipient molecules. The sequence of contact angle from small to large was starch < sodium benzoate < polyvinylpyrrolidone < sodium carboxymethylcellulose < sodium alginate < chitosan < hydroxypropyl methyl cellulose stearate. In addition, surfactants both in droplets and mixed in excipients significantly reduced the contact angle of excipients, and their abilities to lower contact angle varied. The results of the present study offer a guideline in the formulation design of tablets.

  17. Lipid Nanocapsule-Based Gels for Enhancement of Transdermal Delivery of Ketorolac Tromethamine

    PubMed Central

    Varshosaz, Jaleh; Hajhashemi, Valiollah; Soltanzadeh, Sindokht

    2011-01-01

    Previous reports show ineffective transdermal delivery of ketorolac by nanostructured lipid carriers (NLCs). The aim of the present work was enhancement of transdermal delivery of ketorolac by another colloidal carriers, lipid nanocapsules (LNCs). LNCs were prepared by emulsification with phase transition method and mixed in a Carbomer 934P gel base with oleic acid or propylene glycol as penetration enhancers. Permeation studies were performed by Franz diffusion cell using excised rat abdominal skin. Aerosil-induced rat paw edema model was used to investigate the in vivo performance. LNCs containing polyethylene glycol hydroxyl stearate, lecithin in Labrafac as the oily phase, and dilution of the primary emulsion with 3.5-fold volume of cold water produced the optimized nanoparticles. The 1% Carbomer gel base containing 10% oleic acid loaded with nanoparticles enhanced and prolonged the anti-inflammatory effects of this drug to more than 12 h in Aerosil-induced rat paw edema model. PMID:22175029

  18. The influence of inner hydrophobisation on water transport properties of modified lime plasters

    NASA Astrophysics Data System (ADS)

    Pavlíková, Milena; Pavlík, Zbyšek; Pernicová, Radka; Černý, Robert

    2016-06-01

    The effect of hydrophobic agent admixture on water vapour and liquid water transport properties of newly designed lime plasters is analysed in the paper. The major part of physico - chemical building deterioration is related to the penetration of moisture and soluble salts into the building structure. For that reason, the modified lime plasters were in the broad range of basic material properties tested. From the quantitative point of view, the measured results clearly demonstrate the big differences in the behaviour of studied materials depending on applied modifying admixtures. From the practical point of view, plaster made of lime hydrate, metakaolin, zinc stearate and air-entraining agent can be recommended for renovation purposes. The accessed material parameters will be used as input data for computational modelling of moisture transport in this type of porous building materials and will be stored in material database.

  19. Testing for ethanol markers in hair: discrepancies after simultaneous quantification of ethyl glucuronide and fatty acid ethyl esters.

    PubMed

    Kintz, P; Nicholson, D

    2014-10-01

    The hair of 97 cases were analysed for ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE, including ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) according to the Society of Hair Testing guidelines to examine the role of both tests in documenting chronic excessive alcohol drinking, particularly when the results are in contradiction. 27 (27.8%) results were EtG negative and FAEE positive, when applying the SoHT cut-offs, probably due to the use of alcohol-containing hair products. Four cases (4.1%) were EtG positive and FAEE negative that were attributed to the use of herbal lotions containing EtG.

  20. Use of a static eliminator to improve powder flow.

    PubMed

    Pingali, Kalyana C; Hammond, Stephen V; Muzzio, Fernando J; Shinbrot, Troy

    2009-03-18

    Glidants and lubricants have long been used to improve the flow and processing of pharmaceutical and other powder blends. In this letter, we find that similar improvements can be attained, without additives, by using a simple static eliminator. These results indicate, first, that electrostatic effects on powder blends may be a significant cause of powder aggregation and flow instabilities, and second, that common additives such as magnesium stearate, colloidal silica, and talc may have as their chief effect the reduction of static. This suggests both that intelligent placement of static eliminators can eliminate the need for some of these additives and that judicious engineering of ionic and cationic additives may be effective in improving flow of "clingy" materials.

  1. Tailoring liquid crystalline lipid nanomaterials for controlled release of macromolecules.

    PubMed

    Bisset, Nicole B; Boyd, Ben J; Dong, Yao-Da

    2015-11-10

    Lipid-based liquid crystalline materials are being developed as drug delivery systems. However, the use of these materials for delivery of large macromolecules is currently hindered by the small size of the water channels in these structures limiting control over diffusion behaviour. The addition of the hydration-modulating agent, sucrose stearate, to phytantriol cubic phase under excess water conditions incrementally increased the size of these water channels. Inclusion of oleic acid enabled further control of swelling and de-swelling of the matrix via a pH triggerable system where at low pH the hexagonal phase is present and at higher pH the cubic phase is present. Fine control over the release of various sized model macromolecules is demonstrated, indicating future application to controlled loading and release of large macromolecules such as antibodies. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Improving aerosolization of drug powders by reducing powder intrinsic cohesion via a mechanical dry coating approach.

    PubMed

    Zhou, Qi Tony; Qu, Li; Larson, Ian; Stewart, Peter J; Morton, David A V

    2010-07-15

    The aim of this study was to investigate the effect of coating on the aerosolization of three model micronized powders. Three model powder materials (salbutamol sulphate, salmeterol xinafoate, triamcinolone acetonide) were chosen not only for their different chemical properties but also for their different physical properties such as shape and size distribution. Each powder was coated with 5% (w/w) magnesium stearate using two different dry mechanofusion approaches. After mechanofusion, both poured and tapped densities for all three model drug powders significantly increased. There were significant improvements in aerosolization behavior from an inhaler device for all model powders after mechanofusion. Such improvements in aerosolization were attributed to the reduction in agglomerate strength caused by decreasing powder intrinsic cohesion via surface modification. The work also indicated that the effect of the coating was dependant on the initial particle properties.

  3. Characterization of CdS nanoparticles during their growth in paraffin hot-matrix

    SciTech Connect

    Yordanov, Georgi G.; Adachi, Eiki; Dushkin, Ceco D. . E-mail: nhtd@wmail.chem.uni-sofia.bg

    2007-03-15

    This paper describes the optical and structural properties of CdS nanoparticles during their growth in paraffin hot-matrix containing stearic acid ligand. The nanocrystalline species are characterized with absorbance and photoluminescence spectroscopy, fluorescence microscopy, High-Resolution Transmission Electron Microscopy and X-ray diffraction. The nanoparticles size-distribution, Stokes shift and mean molar concentration are derived from the optical spectra as functions of time. Their time evolution confirms a two-stage nanocrystal growth for CdS. The stability of aggregates of stearate-coated nanoparticles, tested against UV-illumination, shows that the band-edge emission is more sensitive to photo bleaching than the trap-state emission. The obtained new quantitative results are important for the large-scale manufacturing of CdS nanoparticles and their practical applications.

  4. Mascaras may cause irritant contact dermatitis.

    PubMed

    Lodén, M; Wessman, C

    2002-10-01

    The majority of adverse effects of cosmetics have been attributed to soaps in Dutch and English studies, but to eye makeup in a recent Swedish study. The reactions may be caused by irritants or by sensitizing substances. The aim of the present study was to evaluate the irritation potential of commercially available mascaras. The mascaras were exposed to the skin in aluminium chambers. The skin reaction was evaluated using both visual assessments of erythema and non-invasive measurements of the skin reaction. Seven mascaras were tested on 15 healthy individuals in a randomized and blinded fashion. Two of the seven tested mascaras induced pronounced skin inflammation, when applied to normal skin under occlusion. These two mascaras were based on volatile petroleum distillate, in contrast to the other five mascaras that were conventional emulsions with stearate as the main emulsifier. The findings suggest that solvent-based mascaras might induce contact dermatitis due to its content of irritating substances.

  5. Cytoplasmic tail length influences fatty acid selection for acylation of viral glycoproteins.

    PubMed Central

    Veit, M; Reverey, H; Schmidt, M F

    1996-01-01

    We report remarkable differences in the fatty acid content of thioester-type acylated glycoproteins of enveloped viruses from mammalian cells. The E2 glycoprotein of Semliki Forest virus contains mainly palmitic acid like most other palmitoylated proteins analysed so far. However, the other glycoprotein (E1) of the same virus, as well as the HEF (haemagglutinin esterase fusion) glycoprotein of influenza C virus, are unique in this respect because they are acylated primarily with stearic acid. Comparative radiolabelling of uninfected cells with different fatty acids suggests that stearate may also be the prevailing fatty acid in some cellular acylproteins. To look for further differences between palmitoylated and stearoylated glycoproteins we characterized stearoylation in more detail. We identified the acylation site of HEF as a cysteine residue located at the boundary between the transmembrane region and the cytoplasmic tail. The attachment of stearate to HEF and E1 occurs post-translationally in a pre-Golgi compartment. Thus, stearoylated and palmitoylated proteins cannot be discriminated on the basis of the fatty acid linkage site or the intracellular compartment, where acylation occurs. However, stearoylated acylproteins contain a very short, positively charged cytoplasmic tail, whereas in palmitoylated proteins this molecular region is longer. Replacing the short cytoplasmic tail of stearoylated HEF with the long influenza A virus haemagglutinin (HA) tail in an HEF-HA chimera, and subsequent vaccinia T7 expression in CV-1 cells, yielded proteins with largely palmitic acid bound. The reverse chimera, HA-HEF with a short cytoplasmic tail was not fatty acylated at all during expression, indicating that conformational or topological constraints control fatty acid transfer. PMID:8761467

  6. In-line monitoring of the drug content of powder mixtures and tablets by near-infrared spectroscopy during the continuous direct compression tableting process.

    PubMed

    Järvinen, Kristiina; Hoehe, Wolfgang; Järvinen, Maiju; Poutiainen, Sami; Juuti, Mikko; Borchert, Sven

    2013-03-12

    Continuous manufacturing methods offer economic and quality advantages when compared with batch manufacturing methods. In continuous manufacturing, one requires real time assurance of quality of product via the implementation of PAT tools. This study focuses on an in-line near-infrared (NIR) spectroscopic method for determining the drug content of powder mixtures and tablets during a continuous tableting process. Tablets consisting of acetaminophen (20-30%), lactose (69.07-78.93%) and magnesium stearate (0.93-1.07%) were prepared in a continuous direct compression line that consisted of two loss-in-weight feeders, one for acetaminophen and one for premixed lactose and magnesium stearate, and a continuous mixer followed by a rotary tablet press. NIR spectroscopy was applied to the continuous mixer and tablet press to perform a 100% product check at full tableting speed. The UV-spectrophotometric method was used as an off-line reference method to determine the acetaminophen content in the samples. The powder mixture and tablet samples were taken during the process for the calibration of continuous mixer and tablet press, respectively. For the continuous mixer, model creation with the PLS method yielded R-Square and RMSEC (root mean square error of calibration) values of 0.975% and 0.56%, respectively. For the tablet press, the corresponding R-Square and RMSEC values were 0.943% and 0.75%, respectively. A test run demonstrated good predictability in the estimation of the API content in the powder mixtures and tablets during the continuous tableting process. For the continuous mixer and tablet press, the RMSEP (root mean square error of prediction) values were 0.96% and 1.37%, respectively. This study demonstrates that an NIR instrument capable of fast spectra acquisition can be a valuable tool for the in-line monitoring of the continuous mixing and tableting processes.

  7. Preparation and Evaluation of Surface Modified Lactose Particles for Improved Performance of Fluticasone Propionate Dry Powder Inhaler.

    PubMed

    Singh, Deepak J; Jain, Rajesh R; Soni, P S; Abdul, Samad; Darshana, Hegde; Gaikwad, Rajiv V; Menon, Mala D

    2015-08-01

    Dry powder inhalers (DPI) are generally formulated by mixing micronized drug particles with coarse lactose carrier particles to assist powder handling during the manufacturing and powder aerosol delivery during patient use. In the present study, surface modified lactose (SML) particles were produced using force control agents, and their in vitro performance on dry powder inhaler (DPI) formulation of Fluticasone propionate was studied. With a view to reduce surface passivation of high surface free energy sites on the most commonly used DPI carrier, α- lactose monohydrate, effects of various force control agents such as Pluronic F-68, Cremophor RH 40, glyceryl monostearate, polyethylene glycol 6000, magnesium stearate, and soya lecithin were studied. DPI formulations prepared with SML showed improved flow properties, and atomic force microscopy (AFM) studies revealed decrease in surface roughness. The DSC and X-ray diffraction patterns of SML showed no change in the crystal structure and thermal behavior under the experimental conditions. The fine particle fraction (FPF) values of lactose modified with Pluronic F-68, Cremophor RH 40, glyceryl monostearate were improved, with increase in concentration up to 0.5%. Soya lecithin and PEG 6000 modified lactose showed decrease in FPF value with increase in concentration. Increase in FPF value was observed with increasing concentration of magnesium stearate. Two different DPI devices, Rotahaler(®) and Diskhaler(®), were compared to evaluate the performance of SML formulations. FPF value of all SML formulations were higher using both devices as compared to the same formulations prepared using untreated lactose. One month stability of SML formulations at 40°C/75% RH, in permeable polystyrene tubes did not reveal any significant changes in FPF values. SML particles can help in reducing product development hindrances and improve inhalational properties of DPI.

  8. Differences in long-term fixation between mobile-bearing and fixed-bearing knee prostheses at ten to 12 years' follow-up: a single-blinded randomised controlled radiostereometric trial.

    PubMed

    Pijls, B G; Valstar, E R; Kaptein, B L; Nelissen, R G H H

    2012-10-01

    This single-blinded randomised controlled trial investigated whether one design of mobile-bearing (MB) total knee replacement (TKR) has any advantage over a fixed-bearing (FB) design on long-term fixation as measured by radiostereometry. The amount of wear underneath the mobile bearing was also evaluated. A series of 42 knees was randomised to MB or FB tibial components with appropriate polyethylene inserts and followed for between ten and 12 years, or until the death of the patient. The polyethylene in the MB group was superior in that it was gamma-irradiated in inert gas and was calcium-stearate free; the polyethylene in the FB group was gamma-irradiated in air and contained calcium stearate. In theory this should be advantageous to the wear rate of the MB group. At final follow-up the overall mean migration was 0.75 mm (SD 0.76) in the MB group and 0.66 mm (SD 0.4) in the FB group, with the FB group demonstrating more posterior tilt and the MB group more internal rotation. In the FB group there was one revision for aseptic loosening, but none in the MB group. There were no significant differences in clinical or radiological scores. For the MB group, the mean linear wear rate on the under-surface was 0.026 mm/year (SD 0.014). This was significantly smaller than the wear rate of 0.11 mm/year (SD 0.06) in the MB between femur and polyethylene (p < 0.001). Nevertheless, even in a best-case setting the mobile bearings of this TKR design had no apparent advantage in terms of fixation over the FB knee prosthesis at ten to 12 years. The wear underneath the mobile bearing was small and is unlikely to be clinically relevant.

  9. Synthesis of Ni supported by CaO from Ni(0)L complexes (L=dihydrazine, bisethylenediamine)

    NASA Astrophysics Data System (ADS)

    Perangin-angin, Sabarmin; Bangun, Nimpan; Ginting, Adil; Putri, Nabila Karina

    2017-01-01

    Ni/CaO have been synthesis by using thermal reaction between Ni(0)L complexes (L=dihydrazine, bisethylenediamine) and CaO from Ca-stearate or CaCO3. Ni(0)L complexes (L=dihydrazine, bisethylenediamine) prepared by ligand substitution between Cl and hydrazine to perform dichlorohydrazine-Nickel (II) and this reaction monitored by IR spectroscopy and then mention as A. Two ways reaction have been used due to obtain dihydrazine-Nickel (0) from dichlorohydrazine-Nickel (II). The resulted dihydrazine-Nickel (0), B and E, then analyzed by FT-IR. To compare the result, dichloroethylenediamine-Nickel (II), as C, also has been prepared by ligand substitution between Cl and ethylenediamine. The obtain dichloroethylenediaminedichloro-Nickel (II) was then further reduction by using Zinc dust then analyzed by IR spectroscopy and result bisethylenediamine-Nickel (0), as D. The N-H functional groups have been indicated at 3500 - 3000 cm -1 for all A-E. Ni(0)L that obtain then characterized by SEM-EDX to confirm the morphology and molecules that contain in Ni(0)L that form. The reaction between Ca-stearate and dihydrazine-Nickel (0) then resulted black that mention as F. While the reaction between CaCO3 and Ni(0)L respectively resulted Ni/CaO, G, H and I. Ni/CaO surface then characterized by XRD, SEM-EDX and surface area analysis. The EDX analysis confirm the forming compounds of Ni/CaO. All of G, H and I are mesoporous materials.

  10. Calorimetric evidence for phase transitions in spin-label lipid bilayers.

    PubMed

    Chen, S C; Sturtevant, J M; Conklin, K; Gaffney, B J

    1982-09-28

    Dispersions of pure, spin-label phosphatidylcholines in aqueous buffer have been investigated with the Privalov high-sensitivity differential scanning calorimeter. The lipids studied are mixed-chain ones in which C-2 of glycerol bears a spin-label derivative of stearic acid and the fatty acid group at C-1 is palmitate. A well-defined phase transition is observed at 30.3-30.7 degrees C for the phosphatidylcholine labeled near the polar end of the stearate chain (label at C-5). A sharp transition (32-34 degrees C) is also observed for the lipid spin-labeled near the terminal methyl of stearate (label at C-16), but the thermodynamic parameters for this lipid depend strongly on the history of the sample. Calorimetric evidence for hysteresis in the phase transition of the C-16-labeled lipid is presented. In contrast to the above spin-label lipids, the lipid labeled at C-12 does not show a sharp transition in the region 5-35 degrees C. In general, therefore, the thermal behavior of the spin-label phosphatidylcholines resembles that of phosphatidylcholines bearing double bonds or branched methyl groups at similar locations on acyl chains. During synthesis of mixed-chain lipids, migration of acyl chains occurs. Methyl esterification procedures which are compatible with the acid-labile spin-label group are described. Gas chromatographic analysis of methyl esters shows that chain migration during synthesis gives 15-20% of the spin-label fatty acid at the glycerol C-1 position.

  11. Chlordecone impaired biliary excretion: In vivo and in vitro correlates

    SciTech Connect

    Rochelle, L.G.

    1989-01-01

    The focus of this research was to investigate mechanisms of impaired biliary excretion localized to the bile canaliculus. Two modes of chlordecone (CD) action were investigated: (1) direct effects on organic anion transport at the bile canaliculus; and/or (2) general membrane perturbation, indirectly affecting anion transport proteins. Bile canaliculi-enriched fractions (BCEF) were isolated from rat livers in order to characterize effects of CD on this domain of the plasma membranes. CD inhibited the initial rate leading to a peak Na{sup +}-stimulated ({sup 3}H)L-glutamate uptake in BCEF CD inhibition of the initial or Na{sup +}-gradient driven phase of ({sup 3}H)L-glutamate uptake suggested that CD was affecting maintenance of the Na{sup +}-gradient by the BCEF membrane vesicles. In vivo PG anion excretion was inhibited as well as in vitro ({sup 3}H)L-glutamate transport at 24 hr following in vivo CD treatment of rats. Seventy-two hr following CD treatment, rats recovered to control PG excretion levels. PG excretory performance was regained in 72 hr pretreated rats despite an increase in liver CD concentration. Liver CD concentrations in 24 hr pretreated rats were approximately 50% of the concentrations in 72 hr pretreated rats. At low CD concentrations, there was no evidence of general membrane perturbation in terms of immobilization of the lipid electron spin resonance probe, 16-doxyl stearate, in BCEF. Mobility of 16-doxyl stearate in BCEF was reduced at in vitro CD concentrations of 0.20 {mu}mol/mg protein or greater. CD did reduce hepatobiliary permeability to ({sup 14}C)mannitol in 24 and 72 hr pretreated rats; perhaps restricting movement through membrane aqueous pores.

  12. Identification of formulation and manufacturing variables that influence in vitro dissolution and in vivo bioavailability of propranolol hydrochloride tablets.

    PubMed

    Eddington, N D; Ashraf, M; Augsburger, L L; Leslie, J L; Fossler, M J; Lesko, L J; Shah, V P; Rekhi, G S

    1998-11-01

    The purpose of this study was to evaluate the effect of formulation and processing changes on the dissolution and bioavailability of propranolol hydrochloride tablets. Directly compressed blends of 6 kg (20,000 units) were prepared by mixing in a 16-qt V blender and tablets were compressed on an instrumented Manesty D3B tablet press. A half-factorial (2(5-1), Resolution V) design was used to study the following variables: filler ratio (lactose/dicalcium phosphate), sodium starch glycolate level, magnesium stearate level, lubricant blend time, and compression force. The levels and ranges of the excipients and processing changes studied represented level 2 or greater changes as indicated by the Scale-up and Post Approval Changes (SUPAC-IR) Guidance. Changes in filler ratio, disintegrant level, and compression force were significant in affecting percent drug released (Q) in 5 min (Q5) and Q10. However, changes in magnesium stearate level and lubricant blend time did not influence Q5 and Q10. Hardness was found to be affected by changes in all of the variables studied. Some interaction effects between the variables studied were also found to be significant. To examine the impact of formulation and processing variables on in vivo absorption, three batches were selected for a bioavailability study based on their dissolution profiles. Thirteen subjects received four propranolol treatments (slow-, medium-, and fast-dissolving formulations and Inderal 80 mg) separated by 1 week washout according to a randomized crossover design. The formulations were found to be bioequivalent with respect to the log Cmax and log AUC0-infinity. The results of this study suggest that (i) bioavailability/bioequivalency studies may not be necessary for propranolol and perhaps other class 1 drugs after level 2 type changes, and (ii) in vitro dissolution tests may be used to show bioequivalence of propranolol formulations with processing or formulation changes within the specified level 2 ranges

  13. Evaluation of Gum of Moringa oleifera as a Binder and Release Retardant in Tablet Formulation

    PubMed Central

    Panda, D. S.; Choudhury, N. S. K.; Yedukondalu, M.; Si, S.; Gupta, R.

    2008-01-01

    The present study was undertaken to find out the potential of gum from Moringa oleifera to act as a binder and release retardant in tablet formulations. The effect of calcium sulphate dihydrate (water insoluble) and lactose (water soluble) diluent on the release of propranolol hydrochloride was studied. The DSC thermograms of drug, gum and mixture of gum/drug indicated no chemical interaction. Tablets (F1, F2, F3, and F4) were prepared containing calcium sulphate dihydrate as diluent, propranolol hydrochloride as model drug using 10%, 8%, 6% and 4% w/v of gum solution as binder. Magnesium stearate was used as lubricant. Physical and technological properties of granules and tablets like flow rate, Carr index, Hausner ratio, angle of repose, hardness, friability and disintegration time were determined and found to be satisfactory. Tablets were prepared by wet granulation method containing calcium sulphate dihydrate as excipient, propranolol hydrochloride as model drug using 10%, 20% and 30% of gum as release retardant, magnesium stearate was used as lubricant. Similarly tablets were prepared replacing lactose with calcium sulphate dihydrate. Despite of the widely varying physico-chemical characteristics of the excipients, the drug release profiles were found to be similar. The drug release increased with increasing proportions of the excipient and decreased proportion of the gum irrespective of the solubility characteristics of the excipient. The values of release exponent ‘n’ are between 0.37 and 0.54. This implies that the release mechanism is Fickian. There is no evidence that the dissolution or erosion of the excipient has got any effect on the release of the drug. The t50% values for tablets containing calcium sulphate dihydrate were on an average 10%-15% longer than the tablets containing lactose as excipient. These relatively small differences in t50% values suggest that the nature of excipient used appeared to play a minor role in regulating the release

  14. Self-assembled biotransesterified cyclodextrins as potential Artemisinin nanocarriers. II: In vitro behavior toward the immune system and in vivo biodistribution assessment of unloaded nanoparticles.

    PubMed

    Yaméogo, Josias B G; Gèze, Annabelle; Choisnard, Luc; Putaux, Jean-Luc; Mazet, Roseline; Passirani, Catherine; Keramidas, Michelle; Coll, Jean-Luc; Lautram, Nolwenn; Bejaud, Jérôme; Semdé, Rasmané; Wouessidjewe, Denis

    2014-11-01

    In a previous study, we reported on the formulation of Artemisinin-loaded surface-decorated nanoparticles (nanospheres and nanoreservoirs) by co-nanoprecipitation of PEG derivatives (PEG1500 and PEG4000-stearate, polysorbate 80) and biosynthesized γ-CD fatty esters. In the present study, the co-nanoprecipitation was extended to the use of a PEGylated phospholipid, namely DMPE-PEG2000. As our goal was to prepare long-circulating nanocarriers for further systemic delivery of Artemisinin (ART), here, we have investigated, on the one hand, the in vitro behavior of these surface-modified γ-CD-C10 particles toward the immune system (complement activation and macrophage uptake assays) and, on the other hand, their biodistribution features in mice. These experiments showed that the in vitro plasma protein adsorption and phagocytosis by macrophage cells triggered by γ-CD-C10 nanoparticles were significantly reduced when their surface was decorated with amphiphilic PEGylated molecules, in particular PEG1500-stearate, DMPE-mPEG2000 or polysorbate 80. The prolonged blood circulation time assessed by fluorescence imaging was demonstrated for unloaded γ-CD-C10-based nanospheres and nanoreservoir particles containing DMPE-PEG2000 and polysorbate80, respectively. These nanoparticles also proved to be non-hemolytic at the concentration range used in vivo. Within the limits of the conducted experiments, the co-nanoprecipitation technique may be considered as an alternative for surface modification of amphiphilic CD-based drug delivery systems and may be applied to the systemic delivery of ART.

  15. Cold pearl surfactant-based blends.

    PubMed

    Crombie, R L

    1997-10-01

    Pearlizing agents have been used for many years in cosmetic formulations to add a pearlescent effect. Cold pearl surfactant-based blends are mixtures of glycol stearates and surfactants which can be blended in the cold into a wide range of personal-care formulations to create a pearlescent lustre effect. Under controlled manufacturing conditions constant viscosities and crystalline characteristics can be obtained. The development of these blends has been driven by efforts to improve the economics of adding solid pearlizing agents directly into a hot mix formulation. This paper summarizes the history of pearlizers, describes their advantages and physical chemistry of the manufacturing process. Finally some suggestions for applications are given. Les agents nacrants sont utilises depuis de nombreuses annees dans les formulations cosmetiques pour ajouter un effet nacre. Les melanges a froid a base de tensioactif nacre sont des melanges de stearates de glycol et de tensioactifs qui peuvent etre melanges a froid dans une large gamme de formulations d'hygiene personnelle pour creer un effet de lustre nacre. On peut obtenir des viscosites et des proprietes cristallines constantes avec des conditions de fabrication maitrisees. Le developpement de ces melanges a ete porte par les efforts pour ameliorer les couts de l'ajout d'agents nacrants solides directement dans une formulation melangee de l'ajout d'agents nacrants solides directement dans une formulation melangee a chaud. Cet article resume l'histoire des agents nacrants, decrit leurs avantages et al physico-chimie du procede de fabrication. On emet a la fin cetaines suggestions d'applications.

  16. Fluorescence polarization studies of rat intestinal microvillus membranes.

    PubMed Central

    Schachter, D; Shinitzky, M

    1977-01-01

    Rat intestinal microvillus membranes and lipid extracts prepared from them have been studied by fluorescence polarization with three lipid-soluble fluorophores: diphenylhexatriene, retinol, and anthroyl-stearate. The degree of fluorescence polarization of diphenylhexatriene, which provides an index of the "microviscosity" of the lipid regions of the membrane, is exceptionally high in microvillus membranes, the highest yet reported in normal biological membranes. Both the membrane proteins and lipids were found to contribute to the high values. With each of the three probes the polarization values are higher in ileal microvillus membranes as compared to membranes from proximal intestinal segments. Temperature-dependence studies of the fluorescence polarization of diphenylhexatriene and anthroylstearate demonstrate a phase transition in microvillus membranes and in liposomes prepared from their lipid extracts at approximately 26+/-2 degrees C. Ambient pH influences markedly the diphenylhexatriene fluorescence polarization in microvillus membranes but has little effect on that of human erythrocyte ghost membranes. The "microviscosity" of jejunal microvillus membranes is maximal at pH 6.5-7.0 and decreases as much as 50% at pH 3.0, an effect which depends largely upon the membrane proteins. Addition of calcium ions to suspensions of microvillus membranes increases the fluorescence polarization of retinol and anthroyl-stearate, but not that of diphenyl-hexatriene. This confirms the localization of the last compound to the hydrophobic interior of the membrane, relatively distant from the hydrophilic head groups of the polar lipids. Microvillus membrane proteins solubilized with Triton X-100 give relatively high fluorescence polarization and intensity values with retinol, suggesting the presence of binding proteins which could play a role in the normal absorptive mechanism for the vitamin. PMID:14174

  17. Nuclear magnetic resonance spectra and (207)Pb chemical-shift tensors of lead carboxylates relevant to soap formation in oil paintings.

    PubMed

    Catalano, Jaclyn; Yao, Yao; Murphy, Anna; Zumbulyadis, Nicholas; Centeno, Silvia A; Dybowski, Cecil

    2014-01-01

    Soap formation in traditional oil paintings occurs when heavy-metal-containing pigments, such as lead white, 2PbCO3·Pb(OH)2, and lead tin yellow type I, Pb2SnO4, react with fatty acids in the binding medium. These soaps may form aggregates that can be 100-200 μm in diameter, which swell and protrude through the paint surface, resulting in the degradation of the paint film and damage to the integrity of the artwork. The factors that trigger soap formation and the mechanism(s) of the process are not yet well understood. To elucidate these issues, chemical and structural information is necessary, which can be obtained using solid-state (207)Pb and (13)C nuclear magnetic resonance (NMR). In this article, we report (207)Pb and (13)C solid-state NMR spectra and (207)Pb chemical-shift tensors of lead carboxylates implicated in soap formation: lead stearate, lead palmitate, and lead azelate, in addition to lead oleate and lead heptanoate for comparison. The (13)C cross polarization with magic-angle spinning (MAS) spectra of these lead carboxylates show resonance doubling for the carbons closest to the lead, indicating two different conformations of the fatty acid chains in the asymmetric unit. The (207)Pb NMR spectra, from which tensors were determined, were obtained with direct excitation and spin-temperature alternation, with and without MAS, and with the wide band uniform rate smooth truncation Carr-Purcell-Meiboom-Gill pulse sequence. The results of these experiments show that the local coordination environment of lead azelate is different from lead palmitate and lead stearate and could thus be distinguished from these in a paint film displaying soap formation. In addition, comparing the (207)Pb NMR chemical-shift tensors of the lead carboxylates studied shows that crystal packing of the acyl chains may be a factor in determining the coordination environment around the lead.

  18. Phase behaviour and formation of fatty acid esters nanoemulsions containing piroxicam.

    PubMed

    Mat Hadzir, Nursyamsyila; Basri, Mahiran; Abdul Rahman, Mohd Basyaruddin; Salleh, Abu Bakar; Raja Abdul Rahman, Raja Noor Zaliha; Basri, Hamidon

    2013-03-01

    Fatty acid esters are long-chain esters, produced from the reaction of fatty acids and alcohols. They possess potential applications in cosmetic and pharmaceutical formulations due to their excellent wetting behaviour at interfaces and a non-greasy feeling when applied on the skin surfaces. This preliminary work was carried out to construct pseudo-ternary phase diagrams for oleyl laurate, oleyl stearate and oleyl oleate with surfactants and piroxicam. Then, the preparation and optimization study via 'One-At-A-Time Approach' were carried out to determine the optimum amount of oil, surfactants and stabilizer using low-energy emulsification method. The results revealed that multi-phase region dominated the three pseudo-ternary phase diagrams. A composition was chosen from each multi-phase region for preparing the nanoemulsions systems containing piroxicam by incorporating a hydrocolloid stabilizer. The results showed that the optimum amount (w/w) of oil for oleyl laurate nanoemulsions was 30 and 20 g (w/w) for oleyl stearate nanoemulsions and oleyl oleate nanoemulsions. For each nanoemulsions system, the amount of mixed surfactants and stabilizer needed for the emulsification to take place was found to be 10 and 0.5 g (w/w), respectively. The emulsification process via high-energy emulsification method successfully produced nano-sized range particles. The nanoemulsions systems passed the centrifugation test and freeze-thaw cycle with no phase failures, and stable for 3 months at various storage temperatures (3°C, 25°C and 45°C). The results proved that the prepared nanoemulsions system cannot be formed spontaneously, and thus, energy input was required to produce nano-sized range particles.

  19. Thermal behaviour of procaine and benzocaine Part II: compatibility study with some pharmaceutical excipients used in solid dosage forms

    PubMed Central

    2013-01-01

    Background The compatibility study of active substances with excipients finds an important role in the domain of pharmaceutical research, being known the fact that final formulation is the one administered to the patient. In order to evaluate the compatibility between active substance and excipients, different analytical techniques can be used, based on their accuracy, reproducibility and fastness. Results Compatibility study of two well-known active substances, procaine and benzocaine, with four commonly used excipients, was carried out employing thermal analysis (TG/DTG/HF) and Fourier Transform Infrared Spectroscopy (UATR-FT-IR). The selected excipients were microcrystalline cellulose, lactose monohydrate, magnesium stearate and talc. Equal proportion of active substance and excipients (w/w) was utilized in the interaction study. The absolute value of the difference between the melting point peak of active substances and the one corresponding for the active substances in the analysed mixture, as well the absolute value of the difference between the enthalpy of the pure active ingredient melting peak and that of its melting peak in the different analysed mixtures were chosen as indexes of the drug-excipient interaction degree. All the results obtained through thermal analysis were also sustained by FT-IR spectroscopy. Conclusions The corroboration of data obtained by thermal analysis with the ones from FT-IR spectroscopy indicated that no interaction occurs between procaine and benzocaine, with microcrystalline cellulose and talc, as well for the benzocaine-lactose mixture. Interactions were confirmed between procaine and benzocaine respectively and magnesium stearate, and for procaine and lactose. PMID:23962059

  20. A simple route to alloyed quaternary nanocrystals Ag-In-Zn-S with shape and size control.

    PubMed

    Gabka, Grzegorz; Bujak, Piotr; Giedyk, Kamila; Ostrowski, Andrzej; Malinowska, Karolina; Herbich, Jerzy; Golec, Barbara; Wielgus, Ireneusz; Pron, Adam

    2014-05-19

    A convenient method of the preparation of alloyed quaternary Ag-In-Zn-S nanocrystals is elaborated, in which a multicomponent mixture of simple and commercially available precursors, namely, silver nitrate, indium(III) chloride, zinc stearate, 1-dodecanethiol, and sulfur, is used with 1-octadecene as a solvent. The formation of quaternary nanocrystals necessitates the use of an auxiliary sulfur precursor, namely, elemental sulfur dissolved in oleylamine, in addition to 1-dodecanethiol. Without this additional precursor binary ZnS nanocrystals are formed. The optimum reaction temperature of 180 °C was also established. In these conditions shape, size, and composition of the resulting nanocrystals can be adjusted in a controlled manner by changing the molar ratio of the precursors in the reaction mixture. For low zinc stearate contents anisotropic rodlike (ca.3 nm x 10 nm) and In-rich nanocrystals are obtained. This is caused by a significantly higher reactivity of the indium precursor as compared to the zinc one. With increasing zinc precursor content the reactivities of both precursors become more balanced, and the resulting nanocrystals are smaller (1.5-4.0 nm) and become Zn-rich as evidenced by transmission electron microscopy, X-ray diffraction, and energy-dispersive spectrometry investigations. Simultaneous increases in the zinc and sulfur precursor content result in an enlargement of nanocrystals (2.5 to 5.0 nm) and further increase in the molar ZnS content (up to 0.76). The prepared nanoparticles show stable photoluminescence with the quantum yield up to 37% for In and Zn-rich nanocrystals. Their hydrodynamic diameter in toluene dispersion, determined by dynamic light scattering, is roughly twice larger than the diameter of their inorganic core.