Effect of surface hydrophobicity of therapeutic protein loaded in polyelectrolyte nanoparticles on transepithelial permeability.

Oral delivery of protein drugs is greatly limited by low hydrophobicity, an important determinant for intestinal epithelial permeation and bioavailability. Herein, surface properties of recombinant erythropoietin were investigated using the fluorescent dye bis-ANS to monitor relative hydrophobicity for correlation with permeabilities with Caco-2 cells. At various pHs, bis-ANS fluorescence intensity indicated different surface hydrophobicities of erythropoietin molecules.

Freeze-drying and release characteristics of polyelectrolyte nanocarriers for the mucosal delivery of ovalbumin.

Polyelectrolyte complexes (PEC) consisting of an alginate core entrapping the protein ovalbumin and the chitosan coating were prepared by the self-assembly of oppositely charged polyelectrolytes. The PEC were prepared at pH 4.0 and consisted of alginate, ovalbumin and chitosan in a concentration of 0.

Self-assembled Polyelectrolyte Nanocomplexes of Alginate, Chitosan and Ovalbumin.

Polyelectrolyte complex (PEC) nanoparticles for delivering model protein drug ovalbumin were prepared from two polysaccharide polymers, alginate and chitosan. The parameters influencing the complex formation were characterised using colloid titration in combination with dynamic light scattering. The polyelectrolyte interactions and morphology of the formed complexes were verified by differential scanning calorimetry and scanning electron microscopy, respectively.

Toward effective long-term prevention of thromboembolism: novel oral anticoagulant delivery systems.

Despite intensive research in the field of oral anticoagulants over the last decade, simple and effective long-term prevention of thromboembolism is still an unmet need. In addition to drug discovery approaches, the development of novel oral drug delivery systems (DDSs) of clinically well-established anticoagulants presents an intriguing mean of improvement of anticoagulant therapy. The latter topic is therefore the focus of the present review.

Immunonanoparticles--an effective tool to impair harmful proteolysis in invasive breast tumor cells.

Breast cancer cells exhibit excessive proteolysis, which is responsible for extensive extracellular matrix degradation, invasion and metastasis. Besides other proteases, lysosomal cysteine protease cathepsin B has been implicated in these processes and the impairment of its intracellular activity was suggested to reduce harmful proteolysis and hence diminish progression of breast tumors. Here, we present an effective system composed of poly(D,L-lactide-coglycolide) nanoparticles, a specific anti-cytokeratin monoclonal IgG and cystatin, a potent protease inhibitor, that can neutralize the excessive intracellular proteolytic activity as well as invasive potential of breast tumor cells.

Targeting cancer cells using PLGA nanoparticles surface modified with monoclonal antibody.

Targeting drugs to their sites of action is still a major challenge in pharmaceutical research. In this study, polylactic-co-glycolic acid (PLGA) immuno-nanoparticles were prepared for targeting invasive epithelial breast tumour cells. Monoclonal antibody (mAb) was used as a homing ligand and was attached to the nanoparticle surface either covalently or non-covalently.

Intracellular delivery of cysteine protease inhibitor cystatin by polymeric nanoparticles.

Two polymers chitosan and poly(lactide-co-glycolide) copolymer (PLGA) were investigated to develop nanoparticles (NPs) for delivery of protein drug substance into tumour cells. Cystatin was selected as a model protein drug due to its high potential to inhibit cysteine proteases, known to trigger the invasive process. Ionotropic gelation of chitosan with tripolyposphate and precipitation of PLGA polymer from a double emulsion system by a solvent diffusion process were used to produce 250-300 nm in diameter NPs.

Nanoscale polymer carriers to deliver chemotherapeutic agents to tumours.

Nanoscale polymer carriers have the potential to enhance the therapeutic efficacy of antitumour drugs as they can regulate their release, improve their stability and prolong circulation time by protecting the drug from elimination by phagocytic cells or premature degradation. Moreover, nanoscale polymeric carriers are capable of accumulating in tumour cells and tissues due to enhanced permeability and retention effect or by active targeting bearing ligands designed to recognise overexpressed tumour-associated antigens. The diversity in the polymer structures being studied as drug carriers in cancer therapy allows an optimal solution for a particular drug to be provided regarding its delivery and efficacy, and thus the patient's quality of life.

Poly(lactide-co-glycolide) nanoparticles as a carrier system for delivering cysteine protease inhibitor cystatin into tumor cells.

Cystatins are able to inhibit the tumor-associated activity of intracellular cysteine proteases cathepsins B and L and have been suggested as potential anticancer drugs. We have incorporated chicken cystatin, a model protein inhibitor of cysteine proteases, in poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) to improve its bioavailability and delivery into tumor cells. Cystatin-loaded NPs, 300-350 nm in diameter, were prepared by the double emulsion solvent diffusion method using low energy emulsification to preserve the biological activity of the protein.

Cystatin incorporated in poly(lactide-co-glycolide) nanoparticles: development and fundamental studies on preservation of its activity.

Preservation of biological activity is still a major challenge for successful formulation and delivery of protein drugs. Cystatin, a potential protein drug in cancer therapy, was incorporated in poly(lactide-co-glycolide) nanoparticles by the water-in-oil-in-water emulsion solvent diffusion technique. In order to preserve the biological activity of cystatin, a specific modification of the method of producing nanoparticles was introduced.