Search results for "Drug carrier"
showing 10 items of 329 documents
Effect of the surface charge of liposomes on their uptake by angiogenic tumor vessels
2003
Recently, cationic liposomes have been shown to preferentially target the angiogenic endothelium of tumors. It was the aim of our study to investigate the influence of liposomal surface charge on the uptake and kinetics of liposomes into solid tumors and tumor vasculature. Experiments were performed in the amelanotic hamster melanoma A-Mel-3 growing in the dorsal skinfold chamber preparation of male Syrian golden hamsters. Fluorescently labeled liposomes with different surface charge were prepared. Accumulation of i.v. injected liposomes was assessed by quantitative intravital fluorescence microscopy of tumor and surrounding host tissue. The histological distribution of liposomes was analyz…
Gene therapy with iNOS enhances regional contractility and reduces delayed contrast enhancement in a model of postischemic congestive heart failure
2012
Aims: The purpose of this study was to evaluate the effect of transient local myocardial gene transfer of iNOS on cardiac function in a large mammal animal model of heart failure induced by chronic ischemia. Methods: Chronic myocardial ischemia was induced using a minimally invasive model in 16 landrace pigs. Upon demonstration of heart failure, eight animals were treated with liposome-mediated iNOS-gene-transfer by local intramyocardial injection; eight animals received a sham procedure to serve as control. Results: The transmurality of late enhancement (control: 46.4%, iNOS: 35.9%; p < 0.05) was significantly decreased in the ischemic area in the iNOS-treated group. Wall thickness at end-…
Mechanistic basis for unexpected bioavailability enhancement of polyelectrolyte complexes incorporating BCS class III drugs and carrageenans
2013
The objective of this study was to investigate the potential of λ-carrageenan to work as an absorption modifying excipient in combination with formulations of BCS class 3 substances. Trospium chloride was used as a model BCS class 3 substance. Polyelectrolyte complexes of trospium and λ-carrageenan were produced by layer-by-layer complexation. A λ-carrageenan-containing formulation was administered either in capsules size 9 to rats by gavage or directly into ligated intestinal loops of rats. Exceptionally strong variations were observed in the plasma concentrations of the rats that received λ-carrageenan compared to the control group, but enhanced plasma concentrations were observed only in…
Poly(hydroxyethylaspartamide) derivatives as colloidal drug carrier systems
2003
Abstract Poly(hydroxyethylaspartamide) (PHEA) derivatives bearing at the polyaminoacidic backbone poly(ethyleneglycol) (2000 or 5000 Da) or both poly(ethyleneglycol) and hexadecylalkylamine as pendant moieties were investigated as polymeric colloidal drug carriers. The ability of the PHEA derivatives to solubilize hydrophobic drugs was investigated using paclitaxel, amphotericin B and methotrexate. The results demonstrated that the drug solubility depends on both macromolecule composition and drug physicochemical properties. In particular, PEG/hexadecylalkylamine co-grafting increased significantly the solubilization properties of PHEA for the considered drugs while the conjugation of PEG o…
Acute polymyositis during treatment of acute hepatitis C with pegylated interferon alpha-2b.
2005
Hepatitis C virus is not cleared after primary infection in 50-85% of subjects exposed to hepatitis C virus. Anti-viral treatment during the early phase of infection significantly enhances the likelihood of a sustained clearance of hepatitis C virus. Although, a variety of autoimmune-related side effects have been observed during interferon therapy for chronic hepatitis, immuno-mediated adverse reactions have not been reported during treatment of acute hepatitis C. We describe the case of a patient who developed acute hepatitis C virus infection and, while receiving pegylated interferon alpha-2b monotherapy, developed a severe polymyositis. This case illustrates the potential risk of autoim…
Polymeric Nanocarriers for Magnetic Targeted Drug Delivery: Preparation, Characterization, and in Vitro and in Vivo Evaluation
2013
In this paper the preparation of magnetic nano- carriers (MNCs), containing superparamagnetic domains, is reported, useful as potential magnetically targeted drug delivery systems. The preparation of MNCs was performed by using the PHEA-IB-p(BMA) graft copolymer as coating material through the homogenization−solvent evaporation method. Magnetic and nonmagnetic nanocarriers containing flutamide (FLU-MNCs) were prepared. The prepared nanocarriers have been exhaustively characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and magnetic measurements. Biological evaluation was performed by in vitro cytotoxicity and cell uptake tests and in vivo biodistribution …
A 6 day course of liposomal amphotericin B in the treatment of infantile visceral leishmaniasis: the Italian experience
2004
Objectives To evaluate in a retrospective analysis the efficacy and safety of a 6 day course of liposomal amphotericin B (L-AmB) in infantile cases of Mediterranean visceral leishmaniasis (VL) diagnosed over a 10 year period in Italy. Patients and methods Patients included were diagnosed as having VL consecutively admitted from December 1992 to December 2001 at four main referral children's hospitals in Italy and treated with six intravenous doses of 3 mg/kg L-AmB given on days 1-5 and 10 (a total dose of 18 mg/kg). Demographic data, nutritional status, underlying diseases, clinical and laboratory findings, and therapy outcome were considered. Results A total of 164 HIV-negative children (m…
Nitrosoureas Modes of Action and Perspectives in the Use of Hormone Receptor Affine Carrier Molecules
1989
Mechanisms of DNA adduct formation by antineoplastic 2-chloroethyl-N-nitrosoureas (CNUs) and of DNA damage induced by these compounds are discussed. CNUs are alkylating agents that form DNA-DNA cross-links as well as 2-chloroethylated and 2-hydroxyethylated adducts, the N-7-position of guanine being the predominantly alkylated site. A close correlation exists between the potential of a given compound to induce DNA-DNA cross-links and its antineoplastic effectiveness. However, levels of DNA-DNA cross-linking in bone marrow and extent of myelosuppression as measured in rodents are also closely correlated. The design of new cross-linking analogues capable of directing the antineoplastically re…
Ocular tolerability and in vivo bioavailability of poly(ethylene glycol) (PEG)-coated polyethyl-2-cyanoacrylate nanosphere-encapsulated acyclovir.
2001
Acyclovir-loaded polyethyl-2-cyanoacrylate (PECA) nanospheres were prepared by an emulsion polymerization process in the micellar phase and characterized. The influence of the presence of nonionic surfactant as well as other substances [i.e., 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and poly(ethylene glycol) (PEG)], on formulation parameters and loading capacity was investigated. In particular, the presence of PEG resulted in an increase of mean size and size distribution. To obtain PEG-coated PECA nanospheres with a mean size of200 nm, Pluronic F68 at concentrations1.5% (w/v) should be used during preparation. The presence of PEG also resulted in a change in zeta potential, from -25…
Polyhydroxyethylaspartamide-based micelles for ocular drug delivery
2009
In this paper three copolymers of polyhydroxyethylaspartamide (PHEA), bearing in the side chains polyethylene glycol (PEG) and/or hexadecylamine (C(16)) (PHEA-PEG, PHEA-PEG-C(16) and PHEA-C(16) respectively) have been studied as potential colloidal drug carriers for ocular drug delivery. The physical characterization of all three PHEA derivatives, using the Langmuir trough (LT) and micellar affinity capillary electrophoresis (MACE) techniques allowed to assume that whereas alone PHEA backbone is an inert polymer with respect to the interactions with lipid membranes and drug complexation, when PHEA chains are grafted with long alkyl chains like C(16) or in combination C(16) chains and hydrop…