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Ketoprofen suppository dosage forms: in vitro release and in vivo absorption studies in rabbits.

In vitro release of ketoprofen from suppository bases and in vivo absorption in rabbits were studied. Suppositories containing 50 mg of ketoprofen were prepared using theobroma oil, esterified (c10-c18) fatty acids, and polyethylene glycol 1000 bases. The displacement values of the drug were determined and found to be of the order of theobroma oil > esterified (c10-c18) fatty acids and polyethylene glycol 1000 bases. The suppository hardness data revealed that the theobroma oil base produced relatively brittle suppositories. Using the USP dissolution method, the release of ketoprofen was observed to be greatest from polyethylene glycol 1000 suppositories. With the dialysis technique, the maximum release of drug was obtained from theobroma oil suppository containing polysorbate 40 at a 6% level. Selected suppository formulations were evaluated for rectal absorption studies in rabbits. The in vivo data showed that the optimum drug absorption took place from the polyethylene glycol 1000 base and theobroma oil formulation containing 6% polysorbate 40.

Absorption↗

Poly-epsilon-caprolactone nanocapsules containing octyl methoxycinnamate: preparation and characterization.

This study investigates the different nanocapsules (NCs) made of poly-epsilon-caprolactone (PCL) containing the lipophilic sunscreen Escalol 557 [octyl methoxycinnamate (OMC)] and analyzes the influence of nanoparticle-based systems on light-induced decomposition of the sunscreen agent. The NCs were designed and prepared by the solvent displacement method. Formulation parameters, such as the nature and volume of the organic and aqueous phase and the nature and concentration of the surfactants and polymer, have relevant implications on NC elaboration. We investigated the influence of several technological (stirring speed: 300-800 rpm) and formulation factors [polymer amount, 195-244.5 mg; surfactant, Tween 85 (Polysorbate 85), Montanox 80 (Polysorbate 80), and Synperonic PE/F68 (Poloxamer 188) as stabilizing agents; and volume of the organic phase, 20-30 mL of acetone] on the particle size and the OMC loading capacity of the formulations--encapsulation efficiency and yield. The sizes of NC obtained were in the range of 309 to 1042 nm, the encapsulation efficiencies ranged from 93.82% to 99.97%, and yields of NC encapsulation ranged from 48.12% to 86.28%. Of all the preset experimental conditions, Montanox 80, 30 mL of acetone, 244.5 mg of polymer, and a stirring speed of 350 rpm have been selected as the best in this experimental design study. The experimental conditions selected to obtain OMC-loaded NC of 374 nm resulted in a high entrapment percentage (97.52%) and yield (82.95%). The PCL nanoparticles loaded with OMC were effective in reducing light-induced degradation of the sunscreen agent.

Acetone↗

Factors influencing the immunogenicity of therapeutic proteins.

Several diseases and disorders are treatable with therapeutic proteins, but some of these products may induce an immune response, especially when administered as multiple doses over prolonged periods. Antibodies are created by classical immune reactions or by the breakdown of immune tolerance; the latter is characteristic of human homologue products. Many factors influence the immunogenicity of proteins, including structural features (sequence variation and glycosylation), storage conditions (denaturation, or aggregation caused by oxidation), contaminants or impurities in the preparation, dose and length of treatment, as well as the route of administration, appropriate formulation and the genetic characteristics of patients. The clinical manifestations of antibodies directed against a given protein may include loss of efficacy, neutralization of the natural counterpart and general immune system effects (including allergy, anaphylaxis or serum sickness). An upsurge in the incidence of antibody-mediated pure red cell aplasia (PRCA) among patients taking one particular formulation of recombinant human erythropoietin (epoetin-alpha, marketed as Eprex(R)/Erypo(R); Johnson & Johnson) in Europe caused widespread concern. The PRCA upsurge coincided with removal of human serum albumin from epoetin-alpha in 1998 and its replacement with glycine and polysorbate 80. Although the immunogenic potential of this particular product may have been enhanced by the way the product was stored, handled and administered, it should be noted that the subcutaneous route of administration does not confer immunogenicity per se. The possible role of micelle (polysorbate 80 plus epoetin-alpha) formation in the PRCA upsurge with Eprex is currently being investigated.

Biological Products↗

Phase II study of docetaxel in advanced soft tissue sarcomas.

Because of its unusual mechanism of action, docetaxel was selected for study in advanced soft tissue sarcomas of adults as part of a search for new active antisarcoma agents. Patients at least 18 years old with measurable histologically proven advanced nonosseous sarcomas were enrolled if they had ECOG performance status of < or = 2 and satisfactory leukocyte and platelet counts, and hepatic and renal function. Patients with Kaposi's sarcoma, mesothelioma, meningioma, embryonal rhabdomyosarcoma, and extraosseous Ewing's sarcoma were excluded, as were patients with brain or leptomeningeal metastases. Other specific contraindications to participation included other active cancer, previous or concurrent cancer chemotherapy or immunotherapy, and known allergy to the drug vehicle, polysorbate 80. Women of childbearing potential were required to have a negative pregnancy test. Following premedication with dexamethasone and diphenhydramine hydrochloride, docetaxel 100 mg/m2 as a concentrated solution containing 40 mg/ml in polysorbate 80 was infused over 1 h in 250 ml of either dextrose 5% in water or 0.9% saline. Treatment was repeated at 3-week intervals using standard definitions for objective responses. Up to two separate 25% toxicity directed dose reductions were permitted. Between May and December 1993, nine men and nine women registered (median age, 44 years). They received a total of 51 cycles of docetaxel (median, 2.5 cycles). Toxicity included moderate leukopenia (median first cycle nadir, 1.5 x 10(9)/L) but no significant thrombocytopenia. Alopecia, diarrhea, nausea, vomiting, and anorexia were common side effects. Fever, minor skin rashes, stomatitis, and edema were also observed. One drug-related death occurred in a neutropenic patient. One partial regression was observed (5.9%, 95% C.I. 0.15-28.7%) among the 17 eligible patients in a patient with metastatic uterine leiomyosarcoma.

Adult↗

Long-lasting epidural sensory blockade by n-butyl p-aminobenzoate in the dog: neurotoxic or local anesthetic effect?

An aqueous suspension of n-butyl p-aminobenzoate (BAB), a highly lipid-soluble congener of benzocaine, was applied epidurally and around ulnar nerves in dogs. The suspension consisted of 10% BAB and 0.025% polysorbate in 0.9% NaCl. Sensory effects were tested by electrical stimulation. Three epidural injections were given, and the dogs were killed after 21 days. The increase in stimulation threshold was comparable to the effect of lidocaine in a concentration between 0.5% and 1%. Increased sensory threshold lasted for days, whereas no long-lasting motor effects were observed. Pathomorphologic changes were found primarily in the dorsal spinal nerve roots, although slight changes were also found in the ventral spinal roots. White matter degeneration was found only in the lumbar dorsal columns. This result suggested Wallerian degeneration in the dorsal spinal nerves and was at variance with recently published data on epidural BAB. No changes were observed in the ulnar nerves. The authors demonstrated that the pathomorphologic changes were induced by the BAB suspension and not by the suspending additive polysorbate 80. It was postulated that the suspension of BAB, which contains particles of a median size of 15 microns, was mainly confined to the dorsal epidural space where neurolytic changes in axons of the dorsal spinal nerve roots and dorsal columns are induced. This may explain the long-lasting sensory effects seen in intractable cancer pain patients after epidural BAB administration. More research is necessary to define the distribution of BAB in nervous tissue after its epidural administration and to better characterize toxicity, neurolytic effects, and regeneration of nervous tissue after BAB administrations.

Analgesia, Epidural↗

A note on the recovery of micro-organisms from an oil-in-water cream.

The isolation of micro-organisms from the oil-in-water Aqueous Cream BP, has been examined using a variety of solvent systems to disperse the cream prior to membrane filtration or direct inoculation. Pour-plate methods which utilize combinations of either peptone-water (containing 5% w/v polysorbate 80) or nutrient broth (containing 4% w/v Lubrol W) provided the most efficient recovery of Pseudomonas aeruginosa but still allowed less than 20% recovery. White spirit and isopropyl myristate allowed no recovery when used as dispersants. Recoveries of P. aeruginosa varied according to the source of the cream. A combination of 1% w/v polysorbate 80 in 0.1% w/v peptone-water and membrane filtration allowed 63.2% w/v and 67.0% w/v recoveries respectively of Aspergillus niger and Candida albicans from unpreserved aqueous cream, but gave unreproducible results for Escherichia coli and P. aeruginosa. Chlorocresol 0.1% w/v) did not meet the British Pharmacopoeial requirements for efficacy of antimicrobial preservatives when tested against C. albicans using membrane filtration to isolate the micro-organism.

Aspergillus niger↗

Amiodarone instilled into the canine pericardial sac migrates transmurally to produce electrophysiologic effects and suppress atrial fibrillation.

INTRODUCTION: We investigated whether amiodarone delivered into the pericardial sac exerted an effect on atrial and ventricular refractoriness, impulse generation, and conduction and on induced atrial fibrillation. METHODS AND RESULTS: All animals were anesthetized with alpha-chloralose. After a sternotomy, the pericardium was opened and cradled to produce a "container" of approximately 75 mL. Part I experimental animals received amiodarone, 0.5, 1.0, or 5.0 mg/mL, dissolved in 3 mL polysorbate 80 and 5% dextrose in water (D5W) instilled into their pericardial sac for 3-hour intervals. Part II experimental animals received either 1.0 or 5.0 mg/mL of amiodarone. Control dogs received a pericardial solution of 3 mL polysorbate 80 in D5W. Pre- and postinstillation electrophysiologic studies were performed. In part I, the increase in sinus cycle length, 1:1 AV conduction, and effective refractory period (ERP) of atrium, right ventricular (RV) and left ventricular epicardium, and RV endocardium were significantly greater in animals receiving amiodarone compared with controls. Amiodarone concentrations in the tissue samples were highest in the superficial sites of the atria, sinoatrial node, and ventricular epicardial samples and lowest in the interventricular septum. Only trace concentrations of amiodarone and no desethylamiodarone were found in the blood samples. In part II, atrial ERP significantly increased in the animals receiving amiodarone, and the number of episodes of sustained atrial fibrillation that could be induced decreased. CONCLUSIONS: Amiodarone instilled into the pericardial sac migrates transmurally to produce significant electrophysiologic effects at superficial sites and appears to suppress electrically induced atrial fibrillation.

Amiodarone↗

Etoposide (VP-16). Retrospective analysis of treatment in 13 dogs with lymphoma.

A retrospective analysis was performed of the effect of VP-16 (etoposide) in the treatment of 13 dogs with lymphoma. Twelve dogs had achieved partial (two) and complete (ten) responses to combination chemotherapy, but all were out of remission at the time of the trial. One dog had not previously had chemotherapy. There was minimal response to VP-16 chemotherapy in the 13 dogs studied, and only two of 13 dogs had some response to treatment. For one dog, complete and partial remission durations were one and three months, respectively. In another dog, there was partial remission of eight days. There were no responses in the other 11 dogs. The most serious adverse reaction after administration of VP-16 was an acute pruritic cutaneous reaction that occurred in 11 of the 13 dogs, which may have been associated with the vehicle of VP-16, polysorbate 80. Results showed that VP-16 has minimal activity for treatment of dogs with lymphoma that have experienced relapses after treatment with other anti-cancer drugs. More trials are needed with higher dosages and the oral form of the drug, which does not contain polysorbate 80.

Animals↗

Influence of surfactant-treated starch on the disintegration and dissolution of sulphadiazine tablets.

The effects of treating cassava starch with sodium lauryl sulphate and Polysorbate 80 and the method of incorporating the treated and plain starch as disintegrant on the physical properties of sulphadiazine tablets were investigated. Disintegration and dissolution rates were faster with starch in which surfactant was incorporated in dry state than with starch treated with solution of surfactant. A direct correlation was observed between the Hardness-Friability Index and T90 values. Polysorbate 80-treated starch exhibited a better dissolution profile than SLS-treated starch.

Excipients↗

Anaphylactic shock following povidone.

OBJECTIVE: To report a patient with an anaphylactic reaction related to povidone administration. CASE SUMMARY: A 37-year-old man with a history of allergic rhinitis presented with urticaria, dyspnea, wheezing, rhinorrhea, and dysphonia 20 minutes after the intraarticular administration of mepivacaine hydrochloride and paramethasone acetate in his right knee. Two months after this episode, he was admitted for controlled provocation tests. Tests on mepivacaine were negative. The preparation of paramethasone contained the excipients benzalkonium chloride, polysorbate 80, and povidone. In vitro tests and provocation were negative with polysorbate 80 and benzalkonium chloride, but positive with povidone. DISCUSSION: Povidone, a mixture of synthetic polymers, is commonly used as an excipient in pharmaceutical products, an additive in food products, and a dispersant and stabilizer in hairsprays. Although it is well tolerated when used topically or parenterally, local and systemic effects have been reported. Furthermore, multiorgan involvement resulting from accumulation of the drug in the reticuloendothelial system has been described. The immunologic properties of povidone have not been explored in humans, but have been in animals. In fact, the capacity of povidone to release histamine and its immunogenicity are proportional to its molecular weight. An immunoglobulin (Ig) E-mediated hypersensitivity reaction in asthma has been reported. In our case, povidone was responsible for the syndrome. However, we cannot determine the exact mechanism. An unspecific histamine release and/or an IgE-mediated hypersensitivity could be involved. CONCLUSIONS: Povidone was responsible for a severe anaphylactic reaction in our patient. The possibility of an iatrogenic adverse effect caused by the excipient but not by the active ingredient should be considered in patients exhibiting similar symptoms. We believe that the excipients used in the preparation of all medicines should be disclosed.

Adult↗

Freeze-drying of proteins from a sucrose-glycine excipient system: effect of formulation composition on the initial recovery of protein activity.

The purpose of this study was to investigate the effect of sucrose-glycine excipient systems on the stability of selected model proteins during lyophilization. Recovery of protein activity after freeze-drying was examined for the model proteins lactate dehydrogenase and glucose 6-phosphate dehydrogenase in a sucrose-glycine-based excipient system in which the formulation composition was systematically varied. In a sucrose-only excipient system, activity recovery of both model proteins is about 80% and is independent of sucrose concentration over a range from 1 to 40 mg/mL. When both sucrose and glycine are used and the ratio of the 2 excipients is varied, however, activity recovery decreases in a pattern that is consistent with the inhibition of activity recovery by glycine crystals, despite the presence of an adequate amount of sucrose to afford protection. Annealing of sucrose-glycine formulations causes a small but significant decrease in activity recovery relative to unannealed controls, whereas no annealing effect is observed with sucrose-only formulations. Addition of 0.01% polysorbate 80 to the formulation resulted in complete recovery of activity, irrespective of the sucrose-glycine ratio or annealing. Addition of the same concentration of polysorbate 80 to the reconstitution medium caused an increase in activity recovery for each formulation, but the overall pattern remained unchanged. The data are consistent with an interfacial model for lyophilization-associated loss of protein activity involving denaturation at a solid/freeze-concentrate interface.

Animals↗

Solubilization of the lichen metabolite (+)-usnic acid for testing in tissue culture.

The pharmacological testing of natural products can often be hampered by the poor solubility of such compounds in non-toxic solvents. There is thus a need for a suitable agent for solubilization of natural substances to allow testing on a variety of cell lines in-vitro. Such an agent should ideally have no direct effects on any of the commonly used cell lines from a variety of tissues and mammalian species to allow proper comparison. In this study, the lichen metabolite (+)-usnic acid, a dibenzofuran derivative, was used as a prototype for an insoluble natural product with the aim of finding a solvent that was both capable of solubilizing usnic acid and was free of direct activity against a test cell line. Solubilization was measured at different pH values in various concentrations of co-solvents (glycofurol 75, propylene glycol, polyethylene glycol 400), surfactants (polysorbate 20 and Cremophor RH40), and the complexing agent 2-hydroxypropyl-beta-cyclodextrin. The solubility achieved in a 20% aqueous solution was 0.11 mg mL(-1) for propylene glycol, 0.19 for PEG 400, 0.27 for glycofurol 75, 0.57 for Cremophor RH40, 0.68 for 2-hydroxypropyl-beta-cyclodextrin and 0.84 for polysorbate 20. The direct effects of the various solvent systems were tested on the human leukaemia cell line K-562 in a standard proliferation assay. Most of the solvents proved toxic with the exception of propylene glycol, PEG 400 and 2-hydroxypropyl-beta-cyclodextrin. Anti-proliferative activity of usnic acid could be demonstrated with an ED50 (amount of substance required to reduce thymidine uptake to 50% of uptake by untreated control culture) of 4.7 microg mL(-1) using PEG 400 and 2-hydroxypropyl-beta-cyclodextrin but only the latter gave satisfactory solubility. 2-Hydroxypropyl-beta-cyclodextrin was thus identified as a solubilizing agent that fulfilled both set criteria of solubility and lack of toxicity against the test cells.

Analysis of Variance↗

In vitro effect of penetration enhancers on sodium nonivamide acetate in rat skin.

Sodium nonivamide acetate (SNA) is a newly synthetic analogue of capsaicin which produces no overt pungent sensation or irritation. In this present study, the effects and roles of penetration enhancers for SNA through rat skin were investigated by in vitro skin penetration experiment and differential scanning calorimeter (DSC) determination. The penetration fluxes of SNA after the incorporation of enhancers increased in the order of Polysorbate 20 < sodium laurylsulfate < or = benzalkonium chloride. This result was consistent with that of DSC profiles which indicated the disruptive effects of surfactants on the rat stratum corneum increased in the order of Polysorbate 20 < sodium laurylsulfate < benzalkonium chloride. The information gained is particularly helpful in the development of SNA transdermal drug delivery system.

Animals↗

Sublingual delivery of insulin: effects of enhancers on the mucosal lipid fluidity and protein conformation, transport, and in vivo hypoglycemic activity.

The purposes of this study were to evaluate effects of enhancers for sublingual delivering insulin on the mucosal lipid fluidity and protein conformation, transport, and in vivo hypoglycemic activity in normal rats. The effects on sublingual mucosa, and aggregation states of insulin were estimated using fluorescence polarization, and circular dichroism method, respectively. The human immortalized oral epithelial cell monolayer was used for evaluating transport of insulin. Hydroxylpropyl-beta-cyclodextrin (HP-beta-CD), chitosan, polyethylene-polypropylene glycol, polyoxyethylene lauryl ether, polysorbate 80, egg lecithin, or oleic acid, was used as a penetration enhancer, respectively. The fluidity of sublingual mucosal lipid was markedly reduced by these enhancers excluding polysorbate 80, and the secondary structure of the mucosal proteins was also influenced by these enhancers. The hexamers of insulin were dissociated to monomers only by chitosan, polyoxyethylene lauryl ether, and egg lecithin. Nonetheless, plasma glucose levels in normal rats were significantly lowered after sublingual administration of insulin with an enhancer compared with those without an enhancer at the same time-point. The enhancing effects may be due to one or multiple factors: increasing the mucosal lipid fluidity, directly loosing the tight junction of epithelia, and dissociating the hexamers of insulin to monomers. Among these, the opened tight junction may correlate most with the enhancing effect in the mucosal permeability. Because the aggregates of insulin exist, the dissociation of the aggregates by an enhancer would benefit the permeability.

Administration, Sublingual↗

Effect of surface active agents on drug release from polylactic acid-hydrocortisone microcapsules.

Polylactic acid microcapsules containing randomly distributed hydrocortisone particles were prepared. The rate of release of hydrocortisone from the microcapsules in pH 7.4 phosphate buffer was found to be largely increased by the presence of polysorbate 80, cetylpyridinium chloride, or aerosol OT in the dissolution medium. The surfactant effect was attributed to the ability of the surface active agent to improve solvent penetration into the microcapsules by lowering the surface tension at the solid-liquid interface. The effect of the cationic surfactant, cetylpyridinium chloride on the rate of drug release is similar in magnitude to that of the nonionic surfactant, polysorbate 80. In these systems, the rate of drug release from the microcapsules was found to be linearly related to the surface tension of the dissolution medium in the range of 40-60 dyn/cm (x 10(-3) N/m). In the same surface tension range, the effect of aerosol OT on rate increase was found to be much less than those of the cationic and nonionic surfactants. This suggests that the anionic surfactant is not well adsorbed at the interface due to the negative charge characteristics of the surface of the polylactic acid microcapsules. However, at nearly the critical micelle concentration of aerosol OT, where the corresponding surface tension is much lower than those of the cationic and nonionic surfactants, the microcapsules exhibited the highest rate of drug release.

Capsules↗

Vitamin E toxicity in neonatal piglets.

Intravenous vitamin E was associated with the deaths of 38 infants in the US in 1984. Because the vitamin E preparation used contained both vitamin E and a high level of polysorbate detergent, the etiology of the syndrome remains unknown. In this study, we determined the tissue disposition of an intravenous preparation of vitamin E solubilized with polysorbate (E-Ferol) in neonatal piglets. One to two-day-old piglets were injected daily with 50 IU/kg/d of vitamin E for a period of 13 days. Other groups were injected intramuscularly, or with a slow, 7 h intravenous infusion with 50 IU/kg/d vitamin E for six days. Massive splenic accumulation of vitamin E (16,004 micrograms/g vs 73 micrograms/g in controls) occurred following rapid injection, with far lesser concentrations in the liver and lung. Levels of vitamin E in the kidney and heart were only slightly above control. Tissue changes correlated with dosage and duration of vitamin E administration and suggested massive accumulation of vitamin E in cells of the mononuclear phagocyte system. Following slow intravenous infusion the highest levels of vitamin E occurred in the liver rather than spleen. Intramuscular injections at similar doses produced slight, but insignificant changes in tissue levels of vitamin E. We speculate that rapid intravenous injection of vitamin E emulsions produces massive accumulation in phagocytic cells of the spleen and to a lesser extent liver and lung, possibly leading to increased susceptibility to sepsis and/or abnormal pulmonary function. Slow infusions of vitamin E produce major accumulations in the liver rather than spleen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Presystemic metabolism of albendazole: experimental evidence of an efflux process of albendazole sulfoxide to intestinal lumen.

Albendazole (ABZ) presystemic clearance was studied in rat by perfusion of a 25 microM ABZ solution in isolated intestinal loops. Significant secretion of the active metabolite, ABZSO, into the lumen was observed. The metabolite was also present in mesenteric blood. After 30 min of intestinal perfusion, 64% of the ABZ dose had disappeared from lumen. The total amount of ABZSO measured was 0.341 +/- 0.04 nmol/cm with 0.176 +/- 0.03 nmol/cm in mesenteric blood. The metabolite secretion to intestinal lumen was 0.165 +/- 0.05 nmol/cm. Intestinal sulfoxidation was induced by repeated administration of ABZ and ABZ coadministered with surfactants, especially polysorbate 80. The enantioselectivity of the in vitro intestinal sulfoxidation of ABZ showed that the relative contribution of P-450 and flavin-containing monooxygenase was quite similar, but after the induction by ABZ coadministered with polysorbate 80, the cytochrome P-450 system contribution was significantly increased. The appearance of ABZSO in mesenteric blood clearance was also increased under these conditions.

Albendazole↗

Preparation and evaluation of bromocryptine mesylate-polydimethylsiloxane matrices.

The aims of the present study were to characterize the compatibility of silicone polymers with bromocryptine mesylate and excipients and to investigate the in vitro release characteristics of the drug from polydimethylsiloxane matrices. Silicon elastomers, MDX-4-4210 and A-2186, were chosen as polymer materials. Compatibility studies of polymers with drug and various liquid and solid excipients such as propylene glycol, polyethylene glycol, glycerol, sorbitan monolaurat, polysorbate 20, polysorbate 80, polyvinylpyrrolidone, citric acid, lactose, sodium chloride and low-molecular-weight gelatin were carried out. After the macroscopic examination of the excipient-polymer formulations, sorbitan monolaurat, propylene glycol, lactose, sodium chloride, citric acid and low molecular weight gelatin were chosen for investigation of the effect of these materials on drug release. Cylinder-shaped drug polymer matrices were prepared for the drug release studies. The best release profile was obtained with the formulation containing MDX-4-4210, 10% of propylene glycol and a kneading mixture of drug: low-molecular-weight gelatine in a ratio of 1:3.

Administration, Intravaginal↗