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Stability of Ala 125 recombinant human interleukin-2 in solution.

Herein, we describe the preformulation study of Ala 125- recombinant human interleukin-2 (rhIL-2A(125)) in solution. This modified form of the natural human IL-2 is obtained by the replacement of cysteine with alanine at position 125. The compatibility of this rhIL-2A(125) with type I borosilicate glass vials showed no significant adsorption at liquid-vial interface. The effect of single excipients on the stability of this lymphokine was evaluated through RP-HPLC, SDS-PAGE and biological activity assay. Polysorbate 80 at high concentrations decreased the stability of rhIL-2A(125) in solution. On the other hand, the use of antioxidants (methionine and EDTA Na(2)) diminished the oxidation rate of the active ingredient. Additionally, a group of amino acids (glutamine, alanine, glycine and histidine) stabilized rhIL-2A(125) in different grades, and glycine at 5 mg mL(-1) allowed for the best stability behaviour. Taken together, these preformulation results can be used to design an adequate liquid vehicle for rhIL-2A(125) to be manufactured for human use.

Amino Acids↗

[The cause of polyurethane catheter cracking during constant infusion of etoposide (VP-16) injection].

We studied the cause of cracking of a clinically used polyurethane (PU) catheter during the constant infusion of etoposide (VP-16) injection (Lastet), administered without dilution to patients as a part of combination high-dose chemotherapy. After VP-16 injection was infused into the PU catheter at a constant infusion rate (30 ml/h) for 24 h, a decrease in the elasticity (36% of untreated) and on increase in the length of the catheter (3.7%) were observed. These changes were significantly higher than those treated with the control saline. The similar changes of the PU catheter were observed after treatment with a basal solution containing polyethylene glycol 400 (PEG 400), polysorbate 80 and ethanol, which is the vehicle of the VP-16 injection, and with ethanol alone. Moreover, obvious degeneration of the internal wall (occurrence of spots like melting) and cutting face (micro-cracking) of the catheter was observed with an electron microscope after treatment with the vehicle. On the other hand, the elasticity or extension of the PU catheter were not changed after treatment with saline or PEG 400. From these findings, it was suggested that the degeneration and subsequent cracking of the PU catheter during the infusion of VP-16 injection was caused by ethanol contained in its injection solution. No cracking or morphological changes of polyvinyl chloride (PVC) and silicone catheters were found after treatment with the vehicle solution. However, since it has been reported in previous reports that di(2-ethylhexyl)phthalate was leached from PVC bags, the high dose chemotherapy with the dilution-free VP-16 injection should be achieved safely and effectively using a silicon catheter, rather than the PU catheter.

Antineoplastic Agents, Phytogenic↗

Circadian phase-dependent antinociceptive reaction in mice determined by the hot-plate test and the tail-flick test after intravenous injection of dalargin-loaded nanoparticles.

Peptides normally do not cross the blood-brain barrier (BBB). Previously, it has been shown that the hexapeptide enkephalin analogue dalargin with polysorbate-80-coated nanoparticles (DAL/NP) can be transported across the BBB and is able to exhibit an antinociceptive effect in mice. In the present study, the circadian time and dose dependencies of the antinociceptive effect of different dalargin preparations were investigated. The active preparation (DAL/NP, 5 mg/kg, 10 mg/kg), as well as a dalargin solution in phosphate buffered saline (DAL/SOL, 10 mg/kg) were injected intravenously to groups of 10-12 inbred DBA/2 mice at 12 different circadian times; mice were synchronized to a light-dark (LD) 12:12 regimen. The antinociceptive effect was determined 15 minutes postinjection by the hot-plate test. Experiments with DAL/NP were repeated using the tail-flick test system at two selected times (08:00 and 20:00) to test for dose dependency (2.5, 5, 7.5, 10 mg/kg). Hot-plate latencies were rhythmic under baseline and after DAL/SOL, with acrophases in the dark phase; DAL/SOL did not influence latency time. In contrast, DAL/NP significantly increased reaction time dose dependently; the maximal possible effect was rhythmic with the 10 mg/kg preparation, with a peak effect in the early light phase. Results were confirmed by the tail-flick test. The experiments demonstrate that an enkephalin analogue coated with nanoparticles can easily cross the BBB and is able to display a dose- and time-dependent antinociceptive effect.

Analgesics↗

Effect of composition on biological fate of oil particles after intravenous injection of O/W lipid emulsions.

Plasma concentrations of oil particles after intravenous injection of oil-in-water (O/W) lipid emulsions were monitored based on the plasma concentration of phospholipids (PL) and triglycerides (TG), and the light scattering intensity (LSI) of plasma. Previously, we found that their time profiles after injection of the standard O/W lipid emulsion composed of soybean oil (SO) and egg yolk phosphatides (EYP) were similar and suggested that the oil particles with diameter of about 200 nm were entrapped by reticuloendothelial system (RES). Herein, in order to develop a delivery system to avoid the RES uptake by using the lipid emulsions, biological fate of lipid emulsions with oil particles of various sizes or those emulsified by surfactants with polyoxyethylene segments were subjected to the investigations. Lipid emulsions with oil particles of various sizes (about 150-550 nm) were prepared by altering EYP content. The oil particles were stable in plasma in vitro, but oil particle size decreased time-dependently after intravenous injection. Plasma clearance of oil particles depended on their initial size and was decreased by pretreatment with dextran sulfate 500 (DS500), a known RES suppressor. These results suggested that oil particles are still entrapped by RES, even for small-sized oil particles (about 150 nm). Lipid emulsion with small-sized oil particles was also prepared using medium chain triglycerides. The oil particles were stable in vitro, but the time profiles of plasma concentrations of PL and TG, and LSI of plasma were different, and oil particle size decreased time-dependently after intravenous injection. Plasma clearance of the oil particles also depended on their initial size and was decreased by DS500, suggesting that in vivo instability could be due to RES-mediated processes. Artificial surfactants with polyoxyethylene segments, HCO-60 (HCO60) and polysorbate 80 (PS80), were used for RES avoidance. HCO60 resulted in drastic reduction of the plasma clearance of the oil particles for both lipid emulsions composed of soybean oil and medium chain triglycerides. The time-dependent decrease of oil particle size after intravenous injection was marginal. In contrast, PS80 could not prolong the circulation time of the oil particles, and their size decreased time-dependently after intravenous injection.

Animals↗

Ice cream structural elements that affect melting rate and hardness.

Statistical models were developed to reveal which structural elements of ice cream affect melting rate and hardness. Ice creams were frozen in a batch freezer with three types of sweetener, three levels of the emulsifier polysorbate 80, and two different draw temperatures to produce ice creams with a range of microstructures. Ice cream mixes were analyzed for viscosity, and finished ice creams were analyzed for air cell and ice crystal size, overrun, and fat destabilization. The ice phase volume of each ice cream were calculated based on the freezing point of the mix. Melting rate and hardness of each hardened ice cream was measured and correlated with the structural attributes by using analysis of variance and multiple linear regression. Fat destabilization, ice crystal size, and the consistency coefficient of the mix were found to affect the melting rate of ice cream, whereas hardness was influenced by ice phase volume, ice crystal size, overrun, fat destabilization, and the rheological properties of the mix.

Chemical Phenomena↗

Application of 1,3-dibromo-5,5-dimethylhydantoin (DBH) instead of bromine gas or bromine water decolorization for drug identification according to PH. EUR. Analytical methods of pharmacopoeias with DBH in respect to environmental and economical concern, Part 14.

PH. EUR. 2002 identifies biotin, flucytosine, polysorbate 80 and sorbic acid using the decolorization of bromine water. These tests can be better performed with 1,3-dibromo-5,5-dimethylhydantoin (DBH) in combination of the reaction with fluorescein sodium resp. sodium bromide. Also fluorescein sodium PH. EUR. Suppl 2002 can be identified with DBH.

Biotin↗

Three cases of severe acute hepatitis after parenteral administration of amiodarone: the active ingredient is not the only agent responsible for hepatotoxicity.

Amiodarone is one of the most effective antiarrhythmic drugs available and is widely prescribed despite several potentially life-threatening side-effects. Hepatotoxicity is the most frequent one during long-term oral therapy: occasionally acute hepatitis necessitates the suspension of treatment but monitoring of a transient increase in serum aminotransferases is usually sufficient; the clinical-morphological pictures of liver cirrhosis have also been reported. Fulminant hepatitis soon after a parenteral load of the drug is far less well described in the literature. Most published cases were reversible after the suspension of treatment. A negative challenge after oral amiodarone exposure suggested that polysorbate 80, a solvent added to the intravenous infusion and already implied in the pathogenesis of a similar syndrome observed in infants, is a more likely cause of this complication. The occurrence of acute hepatitis complicating parenteral amiodarone treatment does not preclude subsequent oral use of the drug: an evidence-based therapeutic behavior now definitively consolidated. Because of the rarity of this diagnosis, we report 3 cases of short-term hepatotoxicity secondary to amiodarone treatment for supraventricular tachyarrhythmias: in 2 male patients with dilated cardiomyopathy and in a female with liver disease. The diagnosis was presumptive and based on a thorough drug history, the temporal relationship, the time-course of liver dysfunction, the exclusion of other causes and on the rapid improvement observed after parenteral amiodarone withdrawal in 2 cases; in no case could we find any other explanation for the liver damage. Since amiodarone is sometimes still an irreplaceable antiarrhythmic drug, we raise the question of whether careful and continuous vigilance should be mandatory in patients receiving the drug or whether it is possible to introduce a pharmaceutical preparation not containing the vehicle that induces acute liver toxicity.

Acute Disease↗

Effects of nonionic surfactants on the physical stability of immunoglobulin G in aqueous solution during mechanical agitation.

The objective of this study was to evaluate the influence of nonionic surfactants in the presence of glycine and sodium chloride on the physical stability of immunoglobulin G (IgG) in aqueous solution. Among surfactants suitable for parenteral preparation, Polysorbate 80 (Tween 80) and Polyoxyl 35 Castor Oil (Cremophor EL) were selected. The physical stability of IgG in the absence and in the presence of excipients was investigated in aqueous solution during mechanical agitation (concentration of IgG 15%; pH 7.1; temperature 6 +/- 2 degrees C). Suitable concentrations of Tween 80 and Cremophor EL were experimentally determined by surface tension measurements at 6 +/- 2 degrees C. Glycine and sodium chloride were used in different concentrations. The influence of the excipients on the physical stability of IgG in solution has been examined by surface tension measurements, protein content assay (Kjeldahl and HPLC) and differential scanning calorimetry (DSC). Based on the results of the investigations, it was found that Tween 80 and Cremophor EL, used in experimentally determined critical micelle concentration (cmc), decreased the physical stability of IgG in solution. Tween 80 and Cremophor EL in the presence of glycine (1.5 g/l) could stabilize the IgG in solution during mechanical agitation. The comparison of the effects of Tween 80 and Cremophor EL on the physical stability of IgG, showed that Tween 80 had better stabilization effects on IgG in solution under the experimental conditions selected.

Calorimetry, Differential Scanning↗

Comparative effects of mast cell degranulators on perfused systemic blood vessels of Bufo melanostictus and Rana tigrina.

Three agents known to induce release of mast cell constituents, viz. polymyxin, compound 48/80 and polysorbate-80, were evaluated for effect on perfused blood vessels of R. tigrina and B. melanostictus. The mast cell degranulators caused vasoconstriction in frog and toad, except that for P-80 whose responses in toad were equivocal. Toads showed a general low responsiveness in comparison to frogs. Pharmacologic intervention with pheniramine, metergoline, hydergine, atropine and mecamylamine, respectively ruled out role of histamine, 5-HT, catecholamine or acetylcholine or even autonomic mechanisms in the above phenomena. The observations are suggestive of phylogenetic differences in biochemical profile of mast cells in amphibian species.

Animals↗

Development of a lyophilized formulation of interleukin-2.

Native human interleukin-2 (IL-2) comprises a group of glycoproteins of MW 13,000-17,500. Recombinant human IL-2 (rhIL-2) (Cetus) is derived from E. coli and is not glycosylated. We have evaluated several processes for manufacturing rhIL-2, based on different chaotropic agents for solubilization of insoluble protein pastes. Formulation work carried out with material purified by one of these processes is reported here. Our studies have indicated that the presence of a stabilizer in the form of an amorphous excipient, such as amino acids, a non-ionic surfactant (polysorbate 80), hydroxypropyl-beta-cyclodextrin or human serum albumin was essential for preservation of rhIL-2 during lyophilization. Each of these formulations exhibited its own unique problems. We have overcome these problems through a systematic formulation development program and have been successful in developing several lyophilized formulations of rhIL-2 with optimum properties and performance.

2-Hydroxypropyl-beta-cyclodextrin↗

Anaerobic biodegradability of Tween surfactants used as a carbon source for the microbial reductive dechlorination of hexachlorobenzene.

Three structurally-related, nonionic, polysorbate surfactants (Tween 60, 61, and 65) were used as the sole carbon source to sustain the microbial, sequential reductive dechlorination of hexachlorobenzene (HCB) in a mixed, methanogenic culture derived from a contaminated estuarine sediment. The surfactants were partially degraded and fermented to methane with no measurable accumulation of volatile fatty acids, indicating that methanogenesis was rapid relative to the rates of hydrolysis and acidogenesis. Addition of the methanogenesis inhibitor 2-bromoethanesulfonic acid resulted in acetate accumulation without impact on the sequential dechlorination of HCB. An anaerobic biodegradability assay was performed and the following data were obtained for the Tween 60, 61, and 65, respectively: 53, 62, and 62% COD destruction; 35, 57, and 48% COD to methane conversion; and 38, 38, and 45% COD to acetate conversion. These data suggest that the hydrophobic moiety (stearate) of the surfactants was preferentially degraded, most likely through beta-oxidation, to acetate and ultimately to methane and carbon dioxide. Between 38 and 47% of the initial surfactant COD remained after 46 d incubation, which most likely corresponds to the hydrophilic polyoxyethylene moiety. An anaerobic biodegradation pathway of the Tween surfactants is proposed.

Alkanesulfonic Acids↗

Increased dissolution and physical stability of micronized nifedipine particles encapsulated with a biocompatible polymer and surfactants in a wet ball milling process.

Suspensions of nifedipine, a practically water-insoluble drug, were prepared in the presence of a biocompatible polymer, polyvinylpyrrolidone (PVP, K value 17), and three surfactants, sodium lauryl sulfate (SLS, anionic), cetyltrimethylammonium bromide (CETAB, cationic), polysorbate 80 (Tween 80, nonionic), by wet milling in ceramic ball mills. Nifedipine powders encapsulated with PVP and the surfactants were recovered from the suspensions after milling and evaluated for changes in particle size, morphology, sedimentation rate in aqueous suspensions, crystal form, and dissolution. Particle size analysis indicated that milling of suspensions in solutions of PVP and surfactants is an efficient method for reducing the particle size of nifedipine to below 10 microm. Furthermore, DSC and XPS analysis indicated that during milling the nifedipine crystals were coated with the PVP or surfactants and that milling with PVP stabilized the nifedipine crystal form during milling while nifedipine was gradually amorphisized when milled in a quaternary nifedipine/PVP/SLS/CETAB system. The decrease in particle size caused a significant decrease in sedimentation rate and increased the dissolution rate of nifedipine in simulated gastric fluid when compared to milled nifedipine and powder mixtures of the drug and the excipients.

Biocompatible Materials↗

[Polymeric sorbents for hemoperfusion. Preparation, structure and adsorption properties of chemically modified polymer sorbents for hemoperfusion].

In this work the way of chemical modification of macroporous polymer sorbents with a styrene-divinyl-benzene++ structure was presented. Their modification with amino acids leads to improvement of hemocompatibility of sorbents and to sorption magnification, particularly of hydrophilic polysorbates. In the work the full physical chemical characteristics of the received products was given and their sorption properties in the relation to urea, vitamin B12 and substances from phosphor-organic pesticides group as well as from barbituric acid derivatives were designated.

Biocompatible Materials↗

Effects of the constituents of a corticosteroid enema preparation on colonic blood flow and oxygen uptake in the dog.

A number of currently available therapeutic agents for the management of idiopathic inflammatory bowel disease were studied with respect to their influence on blood flow and oxygen extraction in the dog colon. Some commercially available corticosteroid enemas including Cortenema and its vehicle and sulfasalazine and its split products were delivered intraluminally while arterial pressure, blood flow and oxygen extraction in autoperfused segments of the colon were continuously monitored. Of the agents studied, only Cortenema and its vehicle exerted any appreciable effect on colonic blood flow, producing a sustained 50% increase; this increase in blood flow was confined to the mucosa-submucosal layer. Of the constituents of Cortenema, methylparaben was responsible for 72% of the hyperemia whereas the remainder was due to carboxypolymethylene. The corticosteroid itself had no effect. Oxygen uptake by the colon was reduced by approximately 10% with Cortenema, this reduction being due entirely to polysorbate 80. In vitro analysis of the oxygen uptake effect indicates that the enema exerts a direct metabolic action.

Acrylic Resins↗

Effect of silver on whole cells and spheroplasts of a silver resistant Pseudomonas aeruginosa.

Electron micrographs of a silver resistant strain of Pseudomonas aeruginosa grown in the presence of 50 micrograms/ml Ag+ indicate that the surviving cells are resistant at the level of the cytoplasmic membrane. Spheroplasts of the resistant strain were not lysed by 1 h contact with 8 micrograms/ml Ag+, but were 36% and 22% lysed by 1 h contact with 20 micrograms/ml chlorhexidine and 40 micrograms/ml polysorbate 80, respectively. Spheroplasts of a silver sensitive strain of P. aeruginosa were lysed by 22% on contact with 1 microgram/ml Ag+ for 1 h.

Cell Membrane↗

Treatment of hot tar burns.

Hot tar burns, although rare, usually occur in workers in the paving and roofing industries. When tar is heated to high temperatures it can cause deep burns, and its removal often causes further damage. However, the use of one of the polysorbates (surface-active agents) makes removal easy and painless.

Adult↗

Use of solid medium for isolation of leptospires of the Hebdomadis serogroup from bovine milk and urine.

Leptospira interrogans serovars hardjo and szwajizak were isolated from the milk of experimentally infected cows only when using bovine albumin polysorbate-80 solid medium. Semisolid media, with and without the addition of 5-fluorouracil, and hamster inoculations were also used in the isolation attempts. These cultural isolation methods were also compared using cows' urine. Semisolid medium with 5-fluorouracil proved to be the most successful. However, the other methods were satisfactory, with solid medium having the lowest percentage of cultural isolations.

Animals↗