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Nephrotoxicity of plasticizers investigated by 48 hours hypothermic perfusion of dog kidneys.

The possible nephrotoxicity of the plasticizers diethyl phthalate and di-2-ethylhexyl phthalate was tested in vitro using a 48 hours continuous pulsatile hypothermic perfusion of canine kidneys with a human albumin perfusion medium. Since polysorbate 80 was used to facilitate the solution of the plasticizers in the perfusion medium, this substance was also tested. Six groups containing 9--15 kidneys were perfused with different amounts of plasticizers and/or polysorbate 80 added. In perfusates containing polysorbate 80 either alone or with one of the two plasticizers, the LDH activity and the potassium concentrations rose significantly higher than in the control group (p less than 0.001). The kidney weight gain was also significantly greater in these groups. A "blind" histological examination of needle biopsies by light microscopy revealed no differences among the groups. Although the biochemical evidence of tissue damage was not tested by re-implantation of the kidneys, we suggest that caution should be exercised in the use of polysorbate 80 in organ perfusion systems.

Animals↗

Effect of some ethoxylated sorbitan alkanoate on hydrocortisone release from methylcellulose gels.

The process of hydrocortisone release from the nonionic polymer--methylcellulose hydrogels with the addition of 1% and 3% ethoxylated sorbitan alkanoate: polysorbate 20 or polysorbate 80, in the presence of 1,2-propylene glycol or PEG 200 has two stages. In the first stage the release rates are higher in comparison with the second stage. Concerning the hydrogel as a two-compartment system with micellas of polysorbates, the release rates of the first stage are in the range 4.27 x 10(-4)-6.23 x 10(-4) h-1 and in the second stage are in the range 8.29 x 10(-6)-1.16 x 10(-5) h-1 what can be affected by HLB of mentioned polysorbates.

Hydrocortisone↗

In vitro release performance and analgesic activity of endomorphin-1 loaded nanoparticles.

Endomorphin-1 normally has a short half-live in blood and brain and has difficulty in penetrating the blood-brain barrier when given intravenously. To transport endomorphin-1 across the blood-brain barrier, the peptide was adsorbed onto the surface of butylcyanoacrylate nanoparticles and coated with polysorbate 80. The release properties of the drug in vitro were demonstrated. The central analgesic effect of the drug was measured by tail flick test. The results of the in vitro release study show that there is a burst release effect at first and a slow and continuous release then followed. A longer analgesic effect was shown when the nanoparticles coated with polysorbate 80 were intravenously injected into mice than with the other groups including endomorphin-1, nanoparticles uncoated with polysorbate 80, and a simple mixture of the three components (drug, nanoparticles, and surfactant) mixed directly. The results showed that the way we used to promote endomorphin-1 penetration of the blood-brain barrier was useful. These results suggested that nanoparticles coated with polysorbate 80 were useful for delivery of EM-1 loaded nanoparticles to target the brain.

Analgesics, Opioid↗

Growth, cultural characteristics, and antibacterial sensitivity of Leptospira interrogans serovar hardjo.

Nutrient requirements of Leptospira interrogans serovar hardjo were investigated using a 1% bovine serum albumin (BSA) medium, supplemented separately with polysorbates (Tweens) 80, 60, 40, 20, NH4Cl, and vitamins thiamine and cyanocobalamin (vitamin B12). L. hardjo was tested in vitro against 30 antibacterial compounds incorporated into semisolid medium (0.2% agar) at 3 compound concentrations. Growth was superior in polysorbate 80 (oleic acid rich) and polysorbate 40 (palmitic rich) media. A linear growth response to vitamin B12 could be shown. Hamster isolates all required thiamine and vitamin B12 for growth. The antibacterial compounds could be classed as: 100% bacteriocidal, bacteriocidal at the 2 highest concentrations, bacteriocidal at only 1 concentration, and completely noninhibitory. The tetracyclines were strongly bacteriocidal. The comparative growth rates of hamster isolates were much reduced when compared to the type strain hardjoprajitno. These studies were performed acknowledging that the polysorbates were mixtures of fatty acids. Nephelometry was used as an accepted method to monitor the synthesis of leptospiral cell mass.

Animals↗

[Transport of the hexapeptide dalargin across the hemato-encephalic barrier into the brain using polymer nanoparticles].

The drug targeting to the brain by polysorbate 80-coated nanoparticles was studied. The leu-enkephalin analog dalargin was used as a model drug for investigating the drug penetration through the blood-brain barrier. The nociceptive threshold was measured by the tail flick test. The intravenous injection of dalargin bound by sorption to poly(butylcyanoacrylate) nanoparticles subsequently coated with polysorbate 80 induced the analgesic effect in 5.0 and 7.5 mg/kg doses. The pretreatment with naloxone prevented this effect No other controls exhibited the analgesic activity, including the dalargin solution (10 mg/kg, i.v.), dalargin bound to nanoparticles not coated with polysorbate 80; and a simple mixture of dalargin, nanoparticles, and polysorbate 80 mixed directly before the intravenous injection. The luminescent and electron microscopy demonstrated the presence of separate nanoparticles in the capillary endothelium and cerebral neurons, as well as luminescent-labeled polymer in Purkinje's cells of the cerebellum.

Animals↗

Chemotherapy of glioblastoma in rats using doxorubicin-loaded nanoparticles.

Glioblastomas belong to the most aggressive human cancers with short survival times. Due to the blood-brain barrier, they are mostly inaccessible to traditional chemotherapy. We have recently shown that doxorubicin bound to polysorbate-coated nanoparticles crossed the intact blood-brain barrier, thus reaching therapeutic concentrations in the brain. Here, we investigated the therapeutic potential of this formulation of doxorubicin in vivo using an animal model created by implantation of 101/8 glioblastoma tumor in rat brains. Groups of 5-8 glioblastoma-bearing rats (total n = 151) were subjected to 3 cycles of 1.5-2.5 mg/kg body weight of doxorubicin in different formulations, including doxorubicin bound to polysorbate-coated nanoparticles. The animals were analyzed for survival (% median increase of survival time, Kaplan-Meier). Preliminary histology including immunocytochemistry (glial fibrillary acidic protein, ezrin, proliferation and apoptosis) was also performed. Rats treated with doxorubicin bound to polysorbate-coated nanoparticles had significantly higher survival times compared with all other groups. Over 20% of the animals in this group showed a long-term remission. Preliminary histology confirmed lower tumor sizes and lower values for proliferation and apoptosis in this group. All groups of animals treated with polysorbate-containing formulations also had a slight inflammatory reaction to the tumor. There was no indication of neurotoxicity. Additionally, binding to nanoparticles may reduce the systemic toxicity of doxorubicin. This study showed that therapy with doxorubicin bound to nanoparticles offers a therapeutic potential for the treatment of human glioblastoma.

Animals↗

Oral bioavailability of the antioxidant astaxanthin in humans is enhanced by incorporation of lipid based formulations.

Astaxanthin is a carotenoid with antioxidant properties, synthesised by plants and algae, and distributed in marine seafood. Astaxanthin is also available as a food supplement, but, like other carotenoids, is a very lipophilic compound and has low oral bioavailability. However, bioavailability can be enhanced in the presence of fat. There is not much information in the literature about the pharmacokinetics of oral astaxanthin in humans. In this open parallel study, healthy male volunteers received a single dose of 40 mg astaxanthin, as lipid based formulations or as a commercially available food supplement, followed by blood sampling for further analysis of plasma concentrations. Pharmacokinetic parameters were calculated to evaluate the extent and rate of absorption from each formulation. The elimination half-life was 15.9+/-5.3 h (n=32), and showed a mono-phasic curve. Three lipid based formulations: long-chain triglyceride (palm oil) and polysorbate 80 (formulation A), glycerol mono- and dioleate and polysorbate 80 (formulation B), and glycerol mono- and dioleate, polysorbate 80 and sorbitan monooleate (formulation C), all showed enhanced bioavailability, ranging from 1.7 to 3.7 times that of the reference formulation. The highest bioavailability was observed with formulation B, containing a high content of the hydrophilic synthetic surfactant polysorbate 80.

Adult↗

Growth, survival, antigenic stability, and virulence of Leptospira interrogans serotype canicola.

Leptospira interrogans serotype canicola (strain NADL A-13) grew from inocula as small as two cells in liquid polysorbate 80 medium (P-80 medium, in P-60, P-40 and P-20 media, and in P-80 medium from which polysorbate, NH4C1 or thiamine had been omitted. It grew well initially in vitamin B12-deleted P-80 medium, but only with inocula as large as 26 x 10(4) cells per ml. P-80 medium lacking both polysorbate and NH4Cl supported light growth from small inocula, but the omission of thiamine and vitamin B12 in addition seriously affected the properties of the medium. Where readily detectable growth did not develop in liquid nutrient-deleted medium, viable ortanisms could often be demonstrated indirectly by subculture to semisolid medium, and their occurrence was influenced by the presence of albumin, thiamine, and vitamin B12. Growth on semisolid media was comparable with that in liquid media of similar composition. The absence of polysorbate 80, thiamine, or vitamin B12 prevented the appearance of Dinger's zones of growth from small inocula. Antigenic composition as measured by microscopic agglutination tests with homologous and heterologous antisera was not appreciably affected by repeated subculturing in various complete and incomplete media. Homogenates of infected-hamster-kidney tissue in bovine serum-albumin diluent still contained viable organisms after 60 days' storage at 23-25 degrees C. Organisms derived from this material after 3 and 16 days' storage showed no loss of virulence. Organisms grown in artificial culture showed no loss of virulence after storage in bovine albumin diluent or phosphate buffer for 7 days at 23-25 degrees C. Cultures of the organism survived without loss of virulence for 15 months in 13 semisolid media of differing complexity. Single colonies derived from five different solid media were grown in semisolid forms of the parent media and stored at 23-25 degrees C for 10 months without loss of virulence.

Animals↗

[A comparative assessment of modern suture materials in stomach resection].

Results of stomach resection by Bilrot-II in 30 experimental animals and 369 patients with gastric and duodenal ulcers were analyzed. Gastroenteroanastomoses were created with various sutures: capron, polysorb, titanium clips. Pneumopression, bacteriologic and morphologic examinations of anastomosis, fibroesophagogastroduodeno- and intestinoscopy, peripheral computed electrogastroenterography were used. It was revealed that mechanical suture with titanium clips was the best. Polysorb thread is inferior in tissue reaction to mechanical suture but superior to capron. Use of polysorb reduced rate of complications in immediate postoperative period 4 times. Taking into consideration high cost of suture devices it is reasonable to introduce polysorb in practice of abdominal surgery.

Anastomosis, Surgical↗

Influence of packaging material on the liquid stability of interferon-alpha2b.

PURPOSE: In this article we studied the effect of the packaging material on the liquid stability of interferon alpha 2b (rhIFN-alpha2b). METHODS: The compatibility of this cytokine with type I borosilicate glass ampoules was evaluated by ELISA and RP-HPLC, at 4 degrees C and after heat sealing. Additionally, the influence of protein concentration (3 and 10 MIU/ml), buffer species (sodium phosphate, sodium citrate and sodium citrate-phosphate) and additives (polysorbate 80 and EDTA Na(2) x 2H(2)O) were studied in samples with and without contact with chlorobutyl stoppers by RP-HPLC. RESULTS: The compatibility of this cytokine in sodium phosphate buffer, with type I borosilicate glass ampoules showed a significant adsorption at the lowest concentration. This influence was eliminated with a polysorbate 80/benzyl alcohol-based vehicle. The effect of the heat sealing of ampoules on the stability of rhIFN-alpha2b showed two degradation peaks when a volume of 1 ml was dispensed. However, with a lower (0.5 ml) volume, the degradation was not detected. On the other hand, samples in contact with chlorobutyl stoppers increased the apparent degradation rate constant in the range of 6.74 +/- 0.38 to 46.34 +/- 3.11 x 10(3) day-(1). This effect significantly decreased in about 1.2- and 1.1-fold when sodium citrate or sodium citrate-phosphate buffers, respectively, were evaluated. Results from the evaluation of EDTA Na(2) x 2H(2)O or polysorbate 80 showed a similar behavior. These additives reduced the apparent degradation rate constant in the range of 2.01 +/- 0.14 to 25.51 +/- 3.57 x 10(3) day-(1). CONCLUSIONS: The adsorption of the cytokine to type I borosilicate glass ampoules was eliminated with a polysorbate 80/benzyl alcohol-based vehicle, and the deleterious effect of the heat sealing decreased with a lower (0.5 ml) volume. Experimental data indicated that the contact with chlorobutyl stoppers accelerates the degradation of rhIFN-alpha2b. However, protein concentration, buffer species and pharmaceutical excipients can modulate this effect.

Absorption↗

Surfactant effect on the dissolution of sulfanilamide granules.

Polysorbate 80 incorporated in sulfanilamide granules was found to depress the dissolution of sulfanilamide. The largest decrease corresponded to the lowest concentration of surfactant used. Sulfanilamide granules formulated with either starch or microcrystalline cellulose also decreased the release of the drug. The effect of starch depressing sulfanilamide dissolution was greater with higher starch content in the granules. However, addition of polysorbate 80 improved the dissolution of sulfanilamide granules containing starch but not those with microcrystalline cellulose. This difference was found to be related to the ability of starch to swell and cause granule disintegration. The inclusion of polysorbate 80 in starch-containing granules produced softer and more densely packed granules which were more responsive to the swelling effect of starch.

Excipients↗

Pharmacokinetics of parenteral 13-cis-retinoic acid formulations in rats.

The pharmacokinetics of three 13-cis-retinoic acid formulations were studied after intraperitoneal (ip) administration to rats. Rats were given ip injections of 2.5 mg of 13-cis-retinoic acid per 360 g of body weight; the drug was administered as an alkaline solution, suspended in corn oil, or as a mixture with polysorbate 80. The alkaline solution was also given intravenously (iv) via the tail vein as a control. The mean elimination rate constant, calculated from data from iv administration, was 0.72 +/- 0.088 h-1 (r = 0.988). The peak concentration in plasma and the time to reach this maximum were 14 mg/L and 0.5 h, 22 mg/L and 2 h, and 10 mg/L and 1 h for the drug administered as an alkaline solution, suspended in corn oil, and as a mixture with polysorbate 80, respectively. The areas under the concentration-time curve (concentration in plasma versus time) were 34.9 +/- 8.78 mg.h/L for the iv dose and 34.1 +/- 9.97, 62.4 +/- 32.3, and 25.9 +/- 12.0 mg.h/L for the ip doses of alkaline solution, suspension in oil, and mixture with polysorbate 80, respectively. Because of the rapid increase of concentration in plasma, which is identical to that of the iv profile, and the ease of its handling and preparation, the ip administered alkaline solution is the preferable formulation.

Animals↗

Solubilization and dissolution properties of a leukotriene-D4 antagonist in micellar solutions.

7-[3-(4-Acetyl-3-hydroxy-2-propylphenoxy)propoxy]-3,4-dihydro-8- propyl-2H-1-benzopyran-2-propionic acid (1) is a leukotriene-D4 antagonist that is quite insoluble in aqueous media. Increased solubilization of 1 was achieved in micellar solutions of polysorbate 80, sodium glycocholate, sodium taurocholate, lysolecithin, and sodium taurocholate plus monoolein. The intrinsic dissolution rate of 1 was measured in the presence and absence of polysorbate 80 at pH 7.0, 8.0, and 10.0. In all the micellar solutions tested, the solubility of 1 was significantly increased. The intrinsic dissolution rate of this compound was also enhanced in micellar solutions of polysorbate 80 and with increasing values of pH. However, the magnitudes of the enhancement of the intrinsic dissolution rate were much less than expected from the enhancement of aqueous solubility.

Benzopyrans↗

Nanoparticles, a drug carrier system to pass the blood-brain barrier, permit central analgesic effects of i.v. dalargin injections.

The Leu-enkephalin dalargin does not normally penetrate the blood brain barrier when given intravenously. Drug targeting to the brain was investigated by using poly(butylcyanoacrylate) nanoparticles which were coated with polysorbate 80. When injected intravenously in mice, dalargin-loaded nanoparticles coated with the polysorbate 80 induced an analgesic effect at doses of 5.0 mg/kg and 7.5 mg/kg dalargin as shown by hindlimb licking on the hot plate. Neither the intravenous injection of dalargin alone at various doses nor the mixture of dalargin-loaded nanoparticles without the polysorbate 80 were able to induce an analgesic activity. This confirms previous observations that nanoparticles provide a convenient method to deliver drugs across the blood-brain barrier.

Analgesics↗

Nanoparticulate systems for brain delivery of drugs.

The blood--brain barrier (BBB) represents an insurmountable obstacle for a large number of drugs, including antibiotics, antineoplastic agents, and a variety of central nervous system (CNS)-active drugs, especially neuropeptides. One of the possibilities to overcome this barrier is a drug delivery to the brain using nanoparticles. Drugs that have successfully been transported into the brain using this carrier include the hexapeptide dalargin, the dipeptide kytorphin, loperamide, tubocurarine, the NMDA receptor antagonist MRZ 2/576, and doxorubicin. The nanoparticles may be especially helpful for the treatment of the disseminated and very aggressive brain tumors. Intravenously injected doxorubicin-loaded polysorbate 80-coated nanoparticles were able to lead to a 40% cure in rats with intracranially transplanted glioblastomas 101/8. The mechanism of the nanoparticle-mediated transport of the drugs across the blood-brain barrier at present is not fully elucidated. The most likely mechanism is endocytosis by the endothelial cells lining the brain blood capillaries. Nanoparticle-mediated drug transport to the brain depends on the overcoating of the particles with polysorbates, especially polysorbate 80. Overcoating with these materials seems to lead to the adsorption of apolipoprotein E from blood plasma onto the nanoparticle surface. The particles then seem to mimic low density lipoprotein (LDL) particles and could interact with the LDL receptor leading to their uptake by the endothelial cells. After this the drug may be released in these cells and diffuse into the brain interior or the particles may be transcytosed. Other processes such as tight junction modulation or P-glycoprotein (Pgp) inhibition also may occur. Moreover, these mechanisms may run in parallel or may be cooperative thus enabling a drug delivery to the brain.

Animals↗

An investigation into interactions between polyacrylic polymers and a non-ionic surfactant: an emulsion preformulation study.

The aim of this study was to investigate possible interactions between a polymeric emulsifier and a non-ionic surfactant, with a view of achieving better understanding of emulsion stabilisation mechanisms. The polymeric emulsifier used was acrylates/C10-30 alkyl acrylate crosspolymer (Pemulen TR-2(R)), while Polyoxyethylene 20 sorbitan mono-oleate (Polysorbate 80) has been chosen as a model surfactant. Both materials were used within the concentration range relevant for their practical application. A 0.2%w/w aqueous dispersion of polymeric emulsifier, containing various amounts of surfactant (from 0.01 to 1.0% w/w) was used throughout the study. Interfacial aspects of the proposed polymer/surfactant interactions were analysed by means of surface tension measurements. Changes in the network structure of the test dispersions were quantified by continuous shear rheometry, supported by the texture analysis. To analyse the influence of hydrophobic alkyl groups present on the Pemulen TR-2(R) chains, an unmodified, hydrophilic polyacrylic acid polymer, Carbopol 934P(R), was assessed under the same conditions. The results obtained by both surface tension and rheological studies have revealed large differences in behaviour of the two polymers in the presence of the model surfactant. Pemulen TR-2(R) was shown to desorb the surfactant from the surface, within the whole concentration range studied. Furthermore, an increase in viscosity and texture profile parameters with increasing Polysorbate 80 concentration up to 0.3% w/w was evident in the case of Pemulen TR-2(R) dispersions. This was followed by a decrease in the gel network strength at higher surfactant concentrations. On the other hand, Carbopol 934P(R) has shown no signs of surfactant desorption and only small changes in the network structure with the increasing concentration of surfactant. It is shown in this study that an interaction between a polymeric emulsifier Pemulen TR-2(R) and a non-ionic surfactant Polysorbate 80 does occur in their aqueous dispersion, and that it is: (a) hydrophobic in nature; (b) concentration-dependent; and (c) has an impact on the rheological properties of dispersion.

Acrylic Resins↗

Rheology and stability of acidified food emulsions treated with high pressure.

The stability and rheology of acidified model oil-in-water emulsions (pH 3.6 +/- 0.1) were evaluated before and after high-pressure treatments. Varying concentrations of canola oil (0-50% w/w), whey protein isolate, polysorbate 60, soy lecithin (0.1-1.5% w/w each), and xanthan (0.0-0.2% w/w) were chosen. Exposure to high pressures (up to 800 MPa for 5 min at 30 degrees C) did not significantly affect the equivalent surface mean diameter D[3,2], flow behavior, and viscoelasticity of the whey protein isolate and polysorbate 60-stabilized emulsions. Pressure treatments had negligible effects on emulsion stability in these systems, except when xanthan (0.2% w/w) was present in which pressure improved the stability of polysorbate 60-stabilized emulsions. Soy lecithin-stabilized emulsions had larger mean particles sizes and lower emulsion volume indices than the others, indicating potential instability, and application of pressure further destabilized these emulsions.

Emulsions↗

Nanoparticle technology for delivery of drugs across the blood-brain barrier.

The Leu-enkephalin dalargin and the Met-enkephalin kyotorphin normally do not cross the blood-brain barrier (BBB) when given systemically. To transport these neuropeptides across the BBB they were adsorbed onto the surface of poly(butylcyanoacrylate) nanoparticles (NPs) and the NPs were coated with polysorbate 80. Central analgesia was measured by the hot plate test in mice. The antidepressant amitriptyline, which normally penetrates the BBB, was used to examine the versatility of the NP method. The concentration of amitriptyline in serum and brain of mice was determined by a gas chromatographic method. Furthermore, NPs were fabricated with different stabilizers. After the adsorption of the peptides on polysorbate 85-stabilized NPs, analgesia was noted after intravenous application when NPs were not coated. The amitriptyline level was significantly enhanced in brain when the substance was adsorbed onto the NP and coated or when the particles were stabilized with polysorbate 85.

Amitriptyline↗