Abstract: Libraries of nanoparticles comprising therapeutic agents and/or imaging agents are disclosed, as well as methods of making, customizing, and using such libraries of nanoparticles.

Abstract: Poly(?-amino esters) prepared from the conjugate addition of bis(secondary amines) or primary amines to a bis(acrylate ester) are described. Methods of preparing these polymers from commercially available starting materials are also provided. These tertiary amine-containing polymers are preferably biodegradable and biocompatible and may be used in a variety of drug delivery systems. Given the poly(amine) nature of these polymers, they are particularly suited for the delivery of polynucleotides. Nanoparticles containing polymer/polynucleotide complexes have been prepared. The inventive polymers may also be used to encapsulate other agents to be delivered. They are particularly useful in delivering labile agents given their ability to buffer the pH of their surroundings.

Abstract: An immobilized catalytic system comprising a carrier layer containing a catalytic entity and a permeable screening layer for providing controlled access between the immobilizing catalytic entity and the surrounding environment and methods of making such systems are disclosed. The carrier layer includes the catalytic entity mixed with a neutral or anionic carrier polymer, which may or may not be cross-linked with a cross-linking agent. The screening layer over the carrier layer includes a matrix of a cationic polymer that is permeable to molecules processed by, produced by or acted upon by the catalytic entity but is not permeable to the catalytic entity itself. Any counter ion to the neutral or anionic carrier polymer cannot be the same as the cationic polymer of the screening layer, and any counter ion to the cationic polymer cannot be the same as the neutral or anionic carrier polymer.

Abstract: Poly(?-amino esters) prepared from the conjugate addition of bis(secondary amines) or primary amines to a bis(acrylate ester) are described. Methods of preparing these polymers from commercially available starting materials are also provided. These tertiary amine-containing polymers are preferably biodegradable and biocompatible and may be used in a variety of drug delivery systems. Given the poly(amine) nature of these polymers, they are particularly suited for the delivery of polynucleotides. Nanoparticles containing polymer/polynucleotide complexes have been prepared. The inventive polymers may also be used to encapsulate other agents to be delivered. They are particularly useful in delivering labile agents given their ability to buffer the pH of their surroundings.

Abstract: An immobilized catalytic system comprising a carrier layer containing a catalytic entity and a permeable screening layer for providing controlled access between the immobilizing catalytic entity and the surrounding environment and methods of making such systems are disclosed. The carrier layer includes the catalytic entity mixed with a neutral or anionic carrier polymer, which may or may not be cross-linked with a cross-linking agent. The carrier layer includes a matrix of a permeable to molecules processed by, produced by or acted upon by the catalytic entity but is not permeable to the catalytic entity itself. Any counter ion to neutral or anionic carrier polymer cannot be the same as the cationic polymer of the screening layer, and any counter ion to the cationic polymer cannot be the same as the neutral or anionic carrier polymer.

Abstract: Poly(&bgr;-amino esters) prepared from the conjugate addition of bis(secondary amines) or primary amines to a bis(acrylate ester) are described. Methods of preparing these polymers from commercially available starting materials are also provided. These tertiary amine-containing polymers are preferably biodegradable and biocompatible and may be used in a variety of drug delivery systems. Given the poly(amine) nature of these polymers, they are particularly suited for the delivery of polynucleotides. Nanoparticles containing polymer/polynucleotide complexes have been prepared. The inventive polymers may also be used to encapsulate other agents to be delivered. They are particularly useful in delivering labile agents given their ability to buffer the pH of their surroundings.

Abstract: Drug-delivery devices and methods of their use are disclosed, which devices consist of at least a semi-interpenetrating network (semi-IPN) hydrogel comprising a first, cationic polymer such as chitosan and a second high molecular weight neutral polymer such as polyethylene oxide, the semi-IPN having been freeze-dried after formation of the semi-IPN, and a drug composition. A therapeutic method of treating gastric disease is also disclosed comprising the step(s) of introducing to a gastric area to be treated a drug-delivery device according to the disclosure, whereupon the device releases the drug or therapeutic agent contained in the device. The hydrogels of the disclosure are advantageously used for site-specific drug delivery in the gastro-intestinal tract where there is a range of pH from 1.0 to 1.5 in the stomach to about 7.5 in the small intestine.

Abstract: Articles of manufacture and methods of making the same, comprising a cationic polymer which has been surface-modified by a method comprising the steps of swelling a cationic polymer in a medium having a pH value <7; applying a surface-modifying agent to the cationic polymer to form a mixture; and adjusting the pH of the mixture to a value .gtoreq.7. A preferred embodiment relates to semipermeable membranes suitable for hemodialysis made from chitosan, the surface of which has been modified by anionic polysaccharides such as dextran or heparin, or anionic polyoxyalkylenes such as acid-modified polyethylene glycol, to improve blood compatibility.