Showing papers on "PEG 400 published in 2002"
TL;DR: Studies on microbial degradation of polyethers revealed that the enzyme was inducibly formed by PPG in the periplasmic, membrane and cytoplasm fractions of a PPG-utilizing bacterium Stenotrophomonas maltophilia, indicating the intracellular metabolism of PPG is the same as that of PEG.
Abstract: This paper summarizes studies on microbial degradation of polyethers. Polyethers are aerobically metabolized through common mechanisms (oxidation of terminal alcohol groups followed by terminal ether cleavage), well-characterized examples being found with polyethylene glycol (PEG). First the polymer is oxidized to carboxylated PEG by alcohol and aldehyde dehydrogenases and then the terminal ether bond is cleaved to yield the depolymerized PEG by one glycol unit. Most probably PEG is anaerobically metabolized through one step which is catalyzed by PEG acetaldehyde lyase, analogous to diol dehydratase. Whether aerobically or anaerobically, the free OH group is necessary for metabolization of PEG. PEG with a molecular weight of up to 20,000 was metabolized either in the periplasmic space (Pseudomonas stutzeri and sphingomonads) or in the cytoplasm (anaerobic bacteria), which suggests the transport of large PEG through the outer and inner membranes of Gram-negative bacterial cells. Membrane-bound PEG dehydrogenase (PEG-DH) with high activity towards PEG 6,000 and 20,000 was purified from PEG-utilizing sphingomonads. Sequencing of PEG-DH revealed that the enzyme belongs to the group of GMC flavoproteins, FAD being the cofactor for the enzyme. On the other hand, alcohol dehydrogenases purified from other bacteria that cannot grow on PEG oxidized PEG. Cytoplasmic NAD-dependent alcohol dehydrogenases with high specificity towards ether-alcohol compound, either crude or purified, showed appreciable activity towards PEG 400 or 600. Liver alcohol dehydrogenase (equine) also oxidized PEG homologs, which might cause fatal toxic syndrome in vivo by carboxylating PEG together with aldehyde dehydrogenase when PEG was absorbed. An ether bond-cleaving enzyme was detected in PEG-utilizing bacteria and purified as diglycolic acid (DGA) dehydrogenase from a PEG-utilizing consortium. The enzyme oxidized glycolic acid, glyoxylic acid, as well as PEG-carboxylic acid and DGA. Similarly, dehydrogenation on polypropylene glycol (PPG) and polytetramethylene glycol (PTMG) was suggested with cell-free extracts of PPG and PTMG-utilizing bacteria, respectively. PPG commercially available is atactic and includes many structural (primary and secondary alcohol groups) and optical (derived from pendant methyl groups on the carbon backbone) isomers. Whether PPG dehydrogenase (PPG-DH) has wide stereo- and enantioselective substrate specificity towards PPG isomers or not must await further purification. Preliminary research on PPG-DH revealed that the enzyme was inducibly formed by PPG in the periplasmic, membrane and cytoplasm fractions of a PPG-utilizing bacterium Stenotrophomonas maltophilia. This finding indicated the intracellular metabolism of PPG is the same as that of PEG. Besides metabolization of polyethers, a biological Fenton mechanism was proposed for degradation of PEG, which was caused by extracellular oxidants produced by a brown-rot fungus in the presence of a reductant and Fe3+, although the metabolism of fragmented PEG has not yet been well elucidated.
227 citations
TL;DR: The results clearly suggest that the use of PG, Tween 80, PEG 400, or HP-beta-CD as solubilizing excipients and the testing of these formulations on 21-day cultured Caco-2 monolayers can predict intestinal absorption of poorly water-soluble drugs in humans.
88 citations
TL;DR: These results clearly demonstrate that PEG 400 adversely influences the gastrointestinal absorption of ranitidine, which has ramifications for the use of PEG400 as a pharmaceutical excipient in oral formulations.
Abstract: Purpose. To investigate the effect of co-administered polyethylene glycol 400 (PEG 400), a pharmaceutical excipient previously shown to accelerate small intestinal transit, on the absorption characteristics of ranitidine from the gastrointestinal tract.
80 citations
TL;DR: This study has analysed the induction of chromosome aberrations by the low molecular weight PEG polymers tetraethylene glycol (TEG), PEG 200 and PEG 400 in a Chinese hamster epithelial liver (CHEL) cell line, which retains sufficient metabolic capability to activate different promutagens and procarcinogens.
Abstract: The human population is widely exposed to polyethylene glycol (PEG) and its chemical derivatives, which are widely used as vehicles or co-solvents in many pharmaceutical and cosmetic preparations. However, PEG polymers of low molecular weight differ significantly from polymers of higher molecular weight in their physico-chemical properties, biological effects on cell permeability and their absorption and excretion, as well as their higher toxicity and possibly genotoxicity. In the present study we have analysed the induction of chromosome aberrations by the low molecular weight PEG polymers tetraethylene glycol (TEG), PEG 200 and PEG 400 in a Chinese hamster epithelial liver (CHEL) cell line, which retains sufficient metabolic capability to activate different promutagens and procarcinogens. The results indicate that in CHEL cells only TEG and PEG 200 are clastogenic. Parallel experiments performed in CHO cells in the presence and absence of rat liver S9 mix showed significant increases in chromosomal aberrations only in cultures treated with TEG in the presence of rat liver S9, indicating that low molecular weight polymers need to be activated to exert their genotoxic activity.
55 citations
TL;DR: In this paper, the Bockris mechanism was used to form the first stage in the iron corrosion mechanism in water-polyethylene glycol (PEG 400) solutions.
48 citations
TL;DR: The studies on the permeability of triprolidine through ethylene-vinyl acetate (EVA) copolymer membrane using two-chamber diffusion cell was carried out to develop the controlled delivery system.
48 citations
TL;DR: The transdermal controlled release of triprolidine system could be developed using the TPX polymer including the plasticizer, and tetra ethyl citrate (TEC) showed the best enhancing effects.
23 citations
TL;DR: The 10% solution of PEG 400 did not have any immunomodulating properties, whereas the undiluted product gave rise to immunosuppression when compared with the saline control, and neither 10% nor the 100% PEG400 preparation possessed adjuvant activity under the conditions of the study.
22 citations
TL;DR: Considering high biological safety of Eudragit RS and PEG 400, EPG might be available to develop the novel thermo-sensitive drug delivery systems.
Abstract: In order to develop the polymer materials having temperature-sensitive and high biological safety, Eudragit RS-PO and polyethylene glycol 400 (PEG 400) blend polymers (EPG) were prepared. The EPGs that have the glass transition temperature (Tg) at around the body temperature were prepared by the addition of 5--13% PEG 400 to Eudragit RS. As glassy polymers are not in thermodynamic equilibrium below their Tg, the effects of isothermal aging on the T(g)s of Eudragit RS and EPG containing 10% PEG 400 (10% EPG) were also studied at various aging temperatures. The Tg values of Eudragit RS increased with the aging time and after 30 d of aging, they apparently reached constant values which markedly differed depending on the aging temperatures. On the other hand, the Tg values of 10% EPG were almost independent of the aging temperature and reached around 33 degrees C at 30 d after aging. The ability as thermo-sensitive polymer of EPG was evaluated by the dissolution test of the acetaminophen (AAP) matrix tablets prepared with EPG. The AAP release rate from the EPG matrix tablets slightly changed below the Tg of tablets, and then, it markedly increased above the Tg. Considering high biological safety of Eudragit RS and PEG 400, EPG might be available to develop the novel thermo-sensitive drug delivery systems.
22 citations
Journal Article•
TL;DR: In this article, the influence of croscarmellose sodium and Aerosil® 200 as adsorbate carriers on in vitro dissolution of nimesulide from solid dispersion systems was investigated.
Abstract: The objective of the present investigation was to study the influence of croscarmellose sodium and Aerosil® 200 as adsorbate carriers on in vitro dissolution of nimesulide from solid dispersion systems. Preliminary studies were carried out using physical blends of nimesulide and adjuvants. Solid dispersions were prepared using the solvent evaporation and co-grinding methods. A 3 2 factorial design was adopted in the co-grinding method using the concentration of croscarmellose sodium and Aerosil® 200 as independent variables. Tween 80, sodium lauryl sulphate (SLS), polyethylene glycol 400 (PEG 400), propylene glycol (PG) and polyvinylpyrrolidone K30 (PVP K30) were used in batches of factorial design. Full and reduced models were evolved for dependent variables, such as the angle of repose, percentage of drug release in 20 min (Q 2 0 ) and percentage of drug release in 30 min (Q 3 0 ). The reduced models were validated using two check-points. Angle of repose 75% and Q 3 0 > 85% were used as constraints for the selection of an optimized batch. Contour plots are presented for the selected dependent variables. Aerosil® 200 was found to be more effective in increasing the drug dissolution compared to croscarmellose sodium. Wettability study was carried out for the pure drug and the optimized batch. Differential scanning calorimetry< and X-ray diffraction studies were carried out in order to characterize the drug. Improved drug dissolution was attributed to decreased crystallinity of the drug, improved wetting and the solubilizing effect of adjuvants such as Tween 80, SLS, PEG 400, PG and PVP K30 from the solid dispersions of nimesulide. In conclusion, dissolution of nimesulide can be modulated using appropriate levels of functional pharmaceutical adjuvants.
17 citations
Journal Article•
TL;DR: The CD and activity data suggest that PEGs can protect alpha helix structures and activity of LDH through the freezing process.
Abstract: Lactate dehydrogenase (LDH) is a tetrameric enzyme that has been used as a model for labile protein drugs. Polyethylene glycols (PEGs) have been proposed as excipients to stabilize labile proteins in solution and during the freezing portion of the lyophilization cycle. The aim of this study was to determine the effects of PEG molecular weight and concentration on the activity of LDH. In general, PEG protection increases with PEG molecular weight and concentration. PEGs slow the loss of activity in LDH solutions stored at 4°C, but are not sufficiently effective to allow for a solution product. PEGs 8000, 10000, and 20000 show full freezing protection at less than 0.01%, while lower molecular weight PEGs need higher concentrations to produce protection upon freezing. Circular dichroism (CD) studies of LDH solutions before and after freezing with PEG 400 and PEG 8000 confirm the activity studies. The CD spectrum of LDH before freezing shows the classic α helix pattern. After unprotected LDH solution is frozen and thawed, the CD spectrum erodes. Low concentrations of PEG 8000 (1% or less) preserve the α helix profile after freezing of the samples. PEG 400 preserves the α helix CD profile in a stepwise fashion with increasing concentrations. The CD and activity data suggest that PEGs can protect α helix structures and activity of LDH through the freezing process.
TL;DR: In this paper, a series of abietic monoester and amide derivatives have been prepared by esterification of ABETIC acid with long chain alcohol blend (Nafol 20+), polyethylene glycol (PEG 400, 600, 1000 and 4000) and hexadecylamine.
Abstract: A series of abietic monoester and amide have been prepared by esterification of abietic acid with long chain alcohol blend (Nafol 20+), polyethylene glycol (PEG 400, 600, 1000 and 4000) and hexadecylamine The abietic diester derivatives were prepared by esterification of abietic–maleic anhydride adduct with Nafol 20+ only or polyethylene glycol-1000 and Nafol 20+ These reactions were carried out to prepare eight abietic acid derivatives The products were purified and characterized by FTIR and 1H NMR analyses The surface-active properties of these compounds were correlated with their effect on pour point and calorific values of crude oil From the results, it has been found that the compound EA23-MN, which has the more negative value of ΔG ad, exhibited maximum pour point depression and increases the calorific values of crude oil and some distillates
Journal Article•
TL;DR: In this paper, the authors used Fick's second law of diffusion, dealing with unsteady state processes, to derive a mathematical model for the absorption rate of polyethylene glycol (PEG 400).
Abstract: One of the problems associated with leather quality is that traditional lubricants ("fatliquors" consisting of oils and surfactants) are known to destabilize collagen fibers Moreover, because they do not promote the retention of essential moisture, they make the leather fibers prone to over-drying We have recently applied an aqueous solution of low molecular weight polyethylene glycol (PEG 400) to leather without using any surfactants The resultant stiffness was characterized by Young's modulus, initial strain energy and acoustic emission methods Results showed that leather treated with polyethylene glycol solutions showed a significant reduction in its stiffness, indicating that PEG has a lubricating effect in leather Efforts were also made to understand how factors affect the absorption of PEG into leather Observations showed that the rate of absorption is not constant; therefore Fick's second law of diffusion, dealing with unsteady state processes, was employed to derive a mathematical model for the absorption rate The effect of temperature on the absorption rate was also included in the model by incorporating a linear equation into Fick's diffusion equation The resultant model fits the experimental data very well It not only depicts the mechanism of absorption, but also predicts the absorption rate as a function of key variables
TL;DR: In this paper, solid-state reaction of Cd(Ac)2·2.5H 2O and Na2S·9H2O in the presence of PEG 400 at room temperature has been successfully demonstrated.
Abstract: CdS nanowires have been successfully prepared by solid-state reaction of Cd(Ac)2·2.5H2O and Na2S·9H2O in the presence of PEG 400 at room temperature.
TL;DR: Recombinant rhamnogalacturonan lyase from Aspergillus aculeatus has been crystallized by a stepwise procedure and X-ray diffraction data have been collected.
Abstract: Recombinant rhamnogalacturonan lyase from Aspergillus aculeatus has been crystallized by a stepwise procedure and X-ray diffraction data have been collected. The crystals were grown using hanging-drop vapour-diffusion and microseeding techniques. Crystals were obtained showing a flat plate morphology. The crystallization conditions were 20% PEG 4000, 9% PEG 400, 0.1 M (NH4)2SO4 and 0.1 M sodium acetate pH 4.4. These crystals diffracted to a resolution of 1.5 A. The unit-cell parameters are a = b = 77.0, c = 170.8 A with the possible space group P43212 or P41212. There is most likely to be one molecule in the asymmetric unit, leading to a calculated solvent content of approximately 47% for the crystals.
Journal Article•
TL;DR: Rectal suppositories with insulin Humulin M3 withHypoglycaemic properties of the prepared suppositories were tested on rabbits and the obtained results were compared with the data acquired after intravenous administration of insulin and subcutaneous injection of insulin.
Abstract: Rectal suppositories with insulin Humulin M3 (30/70) were prepared. Witepsol H15 and a polyoxyethyleneglycol mixture, composed of PEG 400, PEG 1000 and PEG 6000, were used as bases. Tween 60 and sodium salicylate were used as auxiliary substances. Hypoglycaemic properties of the prepared suppositories were tested on rabbits. The obtained results were compared with the data acquired after intravenous administration of insulin and subcutaneous injection of insulin.
TL;DR: In this paper, a method for preparing 4-amino-3,4'-dinitrodiphenyl sulfide is developed, based on the reaction of 2-nitro-4-thiocyanatoaniline with 4-nitronchlorobenzene in aqueous-alkaline medium in the presence of a phase-transfer catalyst (PEG 400 or Katamin AB).
Abstract: A method for preparing 4-amino-3,4'-dinitrodiphenyl sulfide is developed, based on the reaction of 2-nitro-4-thiocyanatoaniline with 4-nitrochlorobenzene in aqueous-alkaline medium in the presence of a phase-transfer catalyst (PEG 400 or Katamin AB).
TL;DR: In this paper, the effect of plasticizer on β-lactoglobulin (Lg) film glass transition temperature (Tg) was investigated to validate the plasticization mechanism.
Abstract: The effect of plasticizer on beta–lactoglobulin (.–Lg) film glass transition temperature (Tg) was investigated to
elucidate the plasticization mechanism. The Tg of film containing polyethylene glycol 400 (PEG 400) as a plasticizer could
not be observed because an ice–melting peak occurred during heating. Films plasticized by propylene glycol (PG), glycerol
(Gly), and PEG 200 possessed similar film Tg values, related to the plasticizer water–binding properties. However, sorbitol
(Sor) and sucrose (Suc) produced higher film Tg values due to their larger MW and solid–state plasticizer behavior. Lubrication
of .–Lg molecules by plasticizer domains external to the .–Lg is suggested as a film plasticization mechanism because no
shift in film Tg was observed with increasing plasticizer content. The size, shape, and physical state of plasticizer were the
key factors affecting film properties, consistent with previous results on mechanical and oxygen permeability (OP) properties.
TL;DR: Cephalexin was synthesized in aqueous two-phase systems (ATPSs) by using penicillin G acylase (PGA) (penicillin amidohydrolase, EC3.11) as a catalyst and 7-aminodeacetoxicephalosporanic acid (7-ADCA) and phenylglycine methyl ester (PGME) as substrates as discussed by the authors.