The Experts below are selected from a list of 5925 Experts worldwide ranked by ideXlab platform
Delwar M Hussain - One of the best experts on this subject based on the ideXlab platform.
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Poloxamer 407 tpgs mixed micelles for delivery of gambogic acid to breast and multidrug resistant cancer
International Journal of Nanomedicine, 2012Co-Authors: Vipin Saxena, Delwar M HussainAbstract:Background Delivery of a high concentration of anticancer drugs specifically to cancer cells remains the biggest challenge for the treatment of multidrug-resistant cancer. Poloxamers and D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS) are known inhibitors of P-glycoprotein (P-gp). Mixed micelles prepared from Poloxamer 407 and TPGS may increase the therapeutic efficacy of the drug by delivering high concentrations inside the cells and inhibiting P-gp. Gambogic acid (GA) is a naturally derived novel anticancer agent, but poor solubility and toxic side effects limit its use. In this study, we have developed Poloxamer 407 and TPGS mixed micelle-encapsulating GA for the treatment of breast and multidrug-resistant cancer.
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Poloxamer 407 tpgs mixed micelles for delivery of gambogic acid to breast and multidrug resistant cancer
International Journal of Nanomedicine, 2012Co-Authors: Vipin Saxena, Delwar M HussainAbstract:Background Delivery of a high concentration of anticancer drugs specifically to cancer cells remains the biggest challenge for the treatment of multidrug-resistant cancer. Poloxamers and D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS) are known inhibitors of P-glycoprotein (P-gp). Mixed micelles prepared from Poloxamer 407 and TPGS may increase the therapeutic efficacy of the drug by delivering high concentrations inside the cells and inhibiting P-gp. Gambogic acid (GA) is a naturally derived novel anticancer agent, but poor solubility and toxic side effects limit its use. In this study, we have developed Poloxamer 407 and TPGS mixed micelle-encapsulating GA for the treatment of breast and multidrug-resistant cancer. Methods GA-loaded Poloxamer 407/TPGS mixed micelles were prepared using a thin film hydration method, and their physicochemical properties were characterized. Cellular accumulation and cytotoxicity of the GA-loaded Poloxamer 407/TPGS mixed micelles were studied in breast cancer cells, MCF-7 cells, and multidrug-resistant NCI/ADR-RES cells. Results The diameter of GA-loaded Poloxamer 407/TPGS mixed micelles was about 17.4 ± 0.5 nm and the zeta potential -13.57 mV. The entrapment efficiency of GA was 93.1% ± 0.5% and drug loading was about 9.38% ± 0.29%. Differential scanning calorimetry and X-ray powder diffraction studies confirmed that GA is encapsulated by the polymers. The in vitro release studies showed that mixed micelles sustained the release of GA for more than 4 days. Results from cellular uptake studies indicated that GA-loaded Poloxamer 407/TPGS mixed micelles had increased cellular uptake of GA in NCI/ADR-RES cells. Cytotoxicity of GA-loaded Poloxamer 407/TPGS mixed micelles was found to be 2.9 times higher in multidrug-resistant NCI/ADR-RES cells, and 1.6 times higher in MCF-7 cells, as compared with unencapsulated GA. Conclusion This study suggests that Poloxamer 407/TPGS mixed micelles can be used as a delivery system for GA to treat breast and multidrug-resistant cancer.
Vipin Saxena - One of the best experts on this subject based on the ideXlab platform.
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Poloxamer 407 tpgs mixed micelles for delivery of gambogic acid to breast and multidrug resistant cancer
International Journal of Nanomedicine, 2012Co-Authors: Vipin Saxena, Delwar M HussainAbstract:Background Delivery of a high concentration of anticancer drugs specifically to cancer cells remains the biggest challenge for the treatment of multidrug-resistant cancer. Poloxamers and D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS) are known inhibitors of P-glycoprotein (P-gp). Mixed micelles prepared from Poloxamer 407 and TPGS may increase the therapeutic efficacy of the drug by delivering high concentrations inside the cells and inhibiting P-gp. Gambogic acid (GA) is a naturally derived novel anticancer agent, but poor solubility and toxic side effects limit its use. In this study, we have developed Poloxamer 407 and TPGS mixed micelle-encapsulating GA for the treatment of breast and multidrug-resistant cancer.
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Poloxamer 407 tpgs mixed micelles for delivery of gambogic acid to breast and multidrug resistant cancer
International Journal of Nanomedicine, 2012Co-Authors: Vipin Saxena, Delwar M HussainAbstract:Background Delivery of a high concentration of anticancer drugs specifically to cancer cells remains the biggest challenge for the treatment of multidrug-resistant cancer. Poloxamers and D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS) are known inhibitors of P-glycoprotein (P-gp). Mixed micelles prepared from Poloxamer 407 and TPGS may increase the therapeutic efficacy of the drug by delivering high concentrations inside the cells and inhibiting P-gp. Gambogic acid (GA) is a naturally derived novel anticancer agent, but poor solubility and toxic side effects limit its use. In this study, we have developed Poloxamer 407 and TPGS mixed micelle-encapsulating GA for the treatment of breast and multidrug-resistant cancer. Methods GA-loaded Poloxamer 407/TPGS mixed micelles were prepared using a thin film hydration method, and their physicochemical properties were characterized. Cellular accumulation and cytotoxicity of the GA-loaded Poloxamer 407/TPGS mixed micelles were studied in breast cancer cells, MCF-7 cells, and multidrug-resistant NCI/ADR-RES cells. Results The diameter of GA-loaded Poloxamer 407/TPGS mixed micelles was about 17.4 ± 0.5 nm and the zeta potential -13.57 mV. The entrapment efficiency of GA was 93.1% ± 0.5% and drug loading was about 9.38% ± 0.29%. Differential scanning calorimetry and X-ray powder diffraction studies confirmed that GA is encapsulated by the polymers. The in vitro release studies showed that mixed micelles sustained the release of GA for more than 4 days. Results from cellular uptake studies indicated that GA-loaded Poloxamer 407/TPGS mixed micelles had increased cellular uptake of GA in NCI/ADR-RES cells. Cytotoxicity of GA-loaded Poloxamer 407/TPGS mixed micelles was found to be 2.9 times higher in multidrug-resistant NCI/ADR-RES cells, and 1.6 times higher in MCF-7 cells, as compared with unencapsulated GA. Conclusion This study suggests that Poloxamer 407/TPGS mixed micelles can be used as a delivery system for GA to treat breast and multidrug-resistant cancer.
Renu Virmani - One of the best experts on this subject based on the ideXlab platform.
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hyperoxic reperfusion is required to reduce infarct size after intravenous therapy with perfluorochemical fluosol da 20 or its detergent component Poloxamer 188 in a poorly collateralized animal model absence of a role of polymorphonuclear leukocytes
Journal of the American College of Cardiology, 1994Co-Authors: Frank D. Kolodgie, Andrew Farb, Greg C Carlson, Patricia S Wilson, Renu VirmaniAbstract:Abstract Objectives . The aim of this study was to assess whether hyperoxic reperfusion contributes to the efficacy of Fluosol 20% or Poloxamer 188 for infarct size reduction and whether suppression of polymorphonuclear leukocyte function is responsible for cardioprotection. Background . The perfluorochemical Fluosol and its detergent component Poloxamer 188 limit myocardial reperfusion-induced injury; however, the underlying mechanism(s) are uncertain. Methods . A series of in vivo and ex vivo studies were performed in a 30-min temporary coronary occlusion rabbit model. Before reperfusion, rabbits received a 25-ml/kg infusion of 1) Fluosol; 2) Poloxamer 188 (equivalent % w/v to Fluosol, 675 mg/kg body weight); or 3) 5% dextrose (control). In protocol A, animals were subjected to either normoxic or hyperoxic reperfusion; in protocols B and C, hyperoxic reperfusion was studied. In protocol B, myocardial blood flow was assessed. In protocol C, polymorphonuclear leukocyte function and myocardial myeloperoxidase were determined. Results . In rabbits subjected to normoxic reperfusion, infarct size (normalized to risk region weight) was not significantly different among groups. In rabbits subjected to hyperoxic reperfusion, infarcts were significantly reduced with both Poloxamer 188 and Fluosol treatment compared with control animals (p = 0.05 and p = 0.0004, respectively). Blood flow at 3 h of reperfusion within the ischemic endocardium was greater in the Fluosol and Poloxamer 188 groups than in the control group (p = 0.001 and p = 0.08, respectively). Myeloperoxidase activity was not affected by treatment, nor was there suppression of polymorphonuclear leukocyte function. Conclusions . Fluosol and Poloxamer 188 reduce infarct size in rabbits subjected to hyperoxic reperfusion. Suppression of polymorphonuclear leukocyte function was not demonstrated, suggesting a greater role for increased arterial oxygen delivery in salvaging ischemic myocardium.
Rainer H Muller - One of the best experts on this subject based on the ideXlab platform.
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solid lipid nanoparticles sln as potential carrier for human use interaction with human granulocytes
Journal of Controlled Release, 1997Co-Authors: Rainer H Muller, S Maassen, C Schwarz, W MehnertAbstract:Abstract A solid lipid nanoparticle (SLN) formulation for intravenous injection was developed as drug carrier for potential human use. The lipid matrix was composed of glycerolbehenate (compritol), the dispersions stabilized by Poloxamer 188 — a surfactant accepted for intravenous administration. The in vitro uptake of SLN by human granulocytes was determined by chemiluminescence (CL), cytotoxicity was assessed by viability measurements using the dimethylthiazolyl-diphenylytetrazolium (MTT) test. Adsorption layers of Poloxamer on colloidal carriers reduce their phagocytic uptake in vitro and in vivo leading to prolonged circulation times in the blood. The SLN had a distinctly lower phagocytic uptake than Poloxamer surface-modified polystyrene model carriers possessing prolonged circulation times in vivo. The cytotoxicity of the glyceride SLN was ≈10-fold below the one of polylactide/glycolide nanoparticles. The SLN might therefore be i.v. carriers with potentially prolonged circulation time and high toxicological acceptance.
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in vitro phagocytosis assay of nano and microparticles by chemiluminescence ii effect of surface modification by coating of particles with Poloxamer on the phagocytic uptake
Journal of Controlled Release, 1993Co-Authors: S Rudt, Rainer H MullerAbstract:Abstract The chemiluminescence assay was used to study the phagocytosis of 3190 nm polystyrene latex particles by human granulocytes. The surface of the particles was modified by the adsorption of Poloxamer blockcopolymers (coating). The relative phagocytic uptake was studied as a function of the molecular structure: the molecular weight and the lengths of the polyethylene oxide (EO) and the polypropylene oxide (PO) chains. Poloxamer polymers with short EO and PO chains were less effective in reducing phagocytosis. The protective effect was found to increase with increasing length of the EO or PO chains. Phagocytosis could be almost completely inhibited by polymers combining longest EO and PO chains (Poloxamers 338 and 407). The observed reductions in in vitro phagocytic uptake were attributed to particle properties related to the thickness of the adsorbed layers, steric stabilization, and reduction in surface hydrophobicity.
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in vitro phagocytosis assay of nano and microparticles by chemiluminescence iii uptake of differently sized surface modified particles and its correlation to particle properties and in vivo distribution
European Journal of Pharmaceutical Sciences, 1993Co-Authors: S Rudt, Rainer H MullerAbstract:Abstract The uptake of surface-modified polysterene particles by cultured human granolocytes was studied as a function of the particle size. Polystyrene particles were modified (coated) by adsorption of Poloxamer block copolymers of increasing molecular weight. The protective effect of the Poloxamer adsorption (coating) layers against phagocytic uptake was releated to the properties of the coated particles (coating layer thickness, surface hydrophobicity). The protective effect of the Poloxamers differed depending on the size of the coated particles. High molecular weight Poloxamers were most effective on large particles (3190 nm), medium molecular weight polymers on medium sized particles (480 nm and 1030 nm). This was attributed to a critical minimum coating layer thickness and related degree of surface hydrophilicity. The Poloxamers were of no or very limited effect in reducing the uptake of small particles (85 nm). Correlations between in vitro reduction of phagocytic uptake by granulocytes and published in vivo organ distributions (clearance by the reticuloendothelial system — RES) of intravenously injected particles are discussed.
Frank D. Kolodgie - One of the best experts on this subject based on the ideXlab platform.
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hyperoxic reperfusion is required to reduce infarct size after intravenous therapy with perfluorochemical fluosol da 20 or its detergent component Poloxamer 188 in a poorly collateralized animal model absence of a role of polymorphonuclear leukocytes
Journal of the American College of Cardiology, 1994Co-Authors: Frank D. Kolodgie, Andrew Farb, Greg C Carlson, Patricia S Wilson, Renu VirmaniAbstract:Abstract Objectives . The aim of this study was to assess whether hyperoxic reperfusion contributes to the efficacy of Fluosol 20% or Poloxamer 188 for infarct size reduction and whether suppression of polymorphonuclear leukocyte function is responsible for cardioprotection. Background . The perfluorochemical Fluosol and its detergent component Poloxamer 188 limit myocardial reperfusion-induced injury; however, the underlying mechanism(s) are uncertain. Methods . A series of in vivo and ex vivo studies were performed in a 30-min temporary coronary occlusion rabbit model. Before reperfusion, rabbits received a 25-ml/kg infusion of 1) Fluosol; 2) Poloxamer 188 (equivalent % w/v to Fluosol, 675 mg/kg body weight); or 3) 5% dextrose (control). In protocol A, animals were subjected to either normoxic or hyperoxic reperfusion; in protocols B and C, hyperoxic reperfusion was studied. In protocol B, myocardial blood flow was assessed. In protocol C, polymorphonuclear leukocyte function and myocardial myeloperoxidase were determined. Results . In rabbits subjected to normoxic reperfusion, infarct size (normalized to risk region weight) was not significantly different among groups. In rabbits subjected to hyperoxic reperfusion, infarcts were significantly reduced with both Poloxamer 188 and Fluosol treatment compared with control animals (p = 0.05 and p = 0.0004, respectively). Blood flow at 3 h of reperfusion within the ischemic endocardium was greater in the Fluosol and Poloxamer 188 groups than in the control group (p = 0.001 and p = 0.08, respectively). Myeloperoxidase activity was not affected by treatment, nor was there suppression of polymorphonuclear leukocyte function. Conclusions . Fluosol and Poloxamer 188 reduce infarct size in rabbits subjected to hyperoxic reperfusion. Suppression of polymorphonuclear leukocyte function was not demonstrated, suggesting a greater role for increased arterial oxygen delivery in salvaging ischemic myocardium.