Abstract: A polymer blend is prepared by dissolving chitosan and a second polymer in an acidic aqueous solution to form an aqueous polymer blend, dehydrating said aqueous polymer blend, and recovering said polymer blend. The second polymer may be selected from the group consisting of polyether glycols including polyethylene glycols; cellulose esters including cellulose acetate; poloxamers; polysaccharides including dextran and guar; polyvinylpyrrolidones; polyvinyl alcohols; and mixtures or copolymers thereof. These polymer blends swell in an acidic environment and deswell in a more neutral or basic environment. This technology is valuable for the dispensing of biologically active material or drugs into a surrounding environment, especially the environment as is found in the gastrointestinal tract.

Abstract: A water soluble, biodegradable reverse thermal gelation system comprising a mixture of at least two types of tri-block copolymer components is disclosed. The tri-block copolymer components are made of a hydrophobic biodegradable polyester A-polymer block and a hydrophilic polyethylene glycol B-polymer block. The drug release and gel matrix erosion rates of the biodegradable reverse thermal gelation system may be modulated by various parameters such as the hydrophobic/hydrophilic component contents, polymer block concentrations, molecular weights and gelation temperatures, and weight ratios of the tri-block copolymer components in the mixture.

Abstract: A water soluble, biodegradable reverse thermal gelation system comprising a mixture of at least two types of tri-block copolymer components is disclosed. The tri-block copolymer components are made of a hydrophobic biodegradable polyester A-polymer block and a hydrophilic polyethylene glycol B-polymer block. The drug release and gel matrix erosion rates of the biodegradable reverse thermal gelation system may be modulated by various parameters such as the hydrophobic/hydrophilic component contents, polymer block concentrations, molecular weights and gelation temperatures, and weight ratios of the tri-block copolymer components in the mixture.

Abstract: The present invention relates to compositions and methods for the modulated release of one or more proteins or peptides. The composition is comprised of a biocompatible polymeric matrix, a protein and/or peptide, and a sparingly water-soluble or essentially insoluble particle. The protein is deposited by adsorption or some other mechanism onto the sparingly water-soluble biocompatible particle wherein the protein-particle combination is dispersed within the polymeric matrix. The deposition of the protein onto the particle acts to modulate the release of the protein or peptide from dosage forms including long-acting dosage systems.

Abstract: A water soluble, biodegradable reverse thermal gelation system comprising a mixture of at least two types of tri-block copolymer components is disclosed. The tri-block copolymer components are made of a hydrophobic biodegradable polyester A-polymer block and a hydrophilic polyethylene glycol B-polymer block. The drug release and gel matrix erosion rates of the biodegradable reverse thermal gelation system may be modulated by various parameters such as the hydrophobic/hydrophilic component contents, polymer block concentrations, molecular weights and gelation temperatures, and weight ratios of the tri-block copolymer components in the mixture.

Abstract: A polymer blend is prepared by dissolving chitosan and a second polymer in an acidic aqueous solution to form an aqueous polymer blend, dehydrating said aqueous polymer blend, and recovering said polymer blend. The second polymer may be selected from the group consisting of polyether glycols including polyethylene glycols; cellulose esters including cellulose acetate; poloxamers; polysaccharides including dextran and guar; polyvinylpyrrolidones; polyvinyl alcohols; and mixtures or copolymers thereof. These polymer blends swell in an acidic environment and deswell in a more neutral or basic environment. This technology is valuable for the dispensing of biologically active material or drugs into a surrounding environment, especially the environment as is found in the gastrointestinal tract.

Abstract: A polymer blend is prepared by dissolving chitosan and a second polymer in an acidic aqueous solution to form an aqueous polymer blend, dehydrating said aqueous polymer blend, and recovering said polymer blend. The second polymer may be selected from the group consisting of polyether glycols including polyethylene glycols; cellulose esters including cellulose acetate; poloxamers; polysaccharides including dextran and guar; polyvinylpyrrolidones; polyvinyl alcohols; and mixtures or copolymers thereof. These polymer blends swell in an acidic environment and deswell in a more neutral or basic environment. This technology is valuable for the dispensing of biologically active material or drugs into a surrounding environment, especially the environment as is found in the gastrointestinal tract.

Abstract: Therapeutic formulations comprising an effective amount of IL-2 or other lymphokine and a biodegradable polymeric carrier having reverse gelation properties and the methods of use thereof for local or both local and systemic control of proliferative cell disorders are disclosed. The formulation can be administered intratumorally/peritumorally and forms an IL-2 containing depot. The IL-2-containing depot provides for continuous, prolonged release of IL-2 sufficient to stimulate the production of cytotoxic T lymphocytes which function both locally and systemically, without causing unacceptable side effects.

Abstract: A composition and method for releasing a bio-active agent or a drug within a biological environment in a controlled manner is disclosed. The composition is a dual phase polymeric agent—delivery composition comprising a continuous biocompatible gel phase, a discontinuous particulate phase comprising defined microparticles and an agent to be delivered. A microparticle containing a bio-active agent is releasably entrained within a biocompatible polymeric gel matrix. The bioactive agent release may be contained in the microparticle phase alone or in both the microparticles and the gel matrix. The release of the agent is prolonged over a period of time, and the delivery may be modulated and/or controlled. In addition, a second agent may be loaded in some of the microparticles and/or the gel matrix.

Abstract: A composition and method for releasing a bio-active agent or a drug within a biological environment in a controlled manner is disclosed. The composition is a dual phase polymeric agent-delivery composition comprising a continuous biocompatible gel phase, a discontinuous particulate phase comprising defined microparticles and an agent to be delivered. A microparticle containing a bio-active agent is releasably entrained within a biocompatible polymeric gel matrix. The bio-active agent release may be contained in the microparticle phase alone or in both the microparticles and the gel matrix. The release of the agent is prolonged over a period of time, and the delivery may be modulated and/or controlled. In addition, a second agent may be loaded in some of the microparticles and/or the gel matrix.

Abstract: A water soluble, biodegradable ABA- or BAB-type tri-block polymer is disclosed that is made up of a major amount of a hydrophobic A polymer block made of a biodegradable polyester and a minor amount of a hydrophilic polyethylene glycol(PEG) B polymer block, having an overall average molecular weight of between about 2000 and 4990, and that possesses reverse thermal gelation properties. Effective concentrations of the tri-block polymer and a drug may be uniformly contained in an aqueous phase to form a drug delivery composition. At temperatures below the gelation temperature of the tri-block polymer the composition is a liquid and at temperatures at or above the gelation temperature the composition is a gel or semi-solid. The composition may be administered to a warm-blooded animal as a liquid by parenteral, ocular, topical, inhalation, transdermal, vaginal, transurethral, rectal, nasal, oral, pulmonary or aural delivery means and is a gel at body temperature. The composition may also be administered as a gel.

Abstract: A water soluble biodegradable ABA- or BAB-type triblock polymer is disclosed that is made up of a major amount of a hydrophobic polymer made of a poly(lactide-co-glycolide) copolymer or poly(lactide) polymer as the A-blocks and a minor amount of a hydrophilic polyethylene glycol polymer B-block, having an overall weight average molecular weight of between about 2000 and 4990, and that possesses reverse thermal gelation properties. Effective concentrations of the triblock polymer and a drug may be uniformly contained in an aqueous phase to form a drug delivery composition. At temperatures below the gelation temperature of the triblock polymer the composition is a liquid and at temperatures at or above the gelation temperature the composition is a gel or semi-solid. The composition may be administered to a warm-blooded animal as a liquid by parenteral, ocular, topical, inhalation, transdermal, vaginal, transurethral, rectal, nasal, oral, pulmonary or aural delivery means and is a gel at body temperature.

Abstract: A biocompatible, heterofunctional, star-shaped poly(ethylene glycol) is described. Methods of making the heterofunctional star-shaped poly(ethylene glycol) and using it for conjugation with proteins are also described.

Abstract: A water soluble biodegradable ABA-type block copolymer made up of a major amount of hydrophobic poly(lactide-co-glycolide) copolymer A-blocks and a minor amount of a hydrophilic polyethylene glycol polymer B-block, having an overall average molecular weight of between about 3100 and 4500, possesses reverse thermal gelation properties. Effective concentrations of the block copolymer and a drug may be uniformly contained in an aqueous phase to form a drug delivery composition. At temperatures below the gelation temperature of the copolymer the composition is a liquid and at temperatures at or above the gelation temperature the composition is a gel or semi-solid. The gelation temperature is preferably at or below body temperature of a warm-blooded animal. The composition may be administered to a warm-blooded animal as a liquid by parenteral, ocular, topical, transdermal, vaginal, transurethral, rectal, nasal, oral, or aural delivery means and is a gel at body temperature.

Abstract: A system and method for the parenteral delivery of a drug in a biodegradable polymeric matrix to a warm blooded animal as a liquid with the resultant formation of a gel depot for the controlled release of the drug. The system comprises an injectable biodegradable block copolymeric drug delivery liquid having reverse thermal gelation properties. The delivery liquid is an aqueous solution having dissolved or dispersed therein an effective amount of a drug intimately contained in a biodegradable block copolymer matrix. The copolymer has a reverse gelation temperature below the body temperature of the animal to which it is administered and is made up of (i) a hydrophobic A polymer block comprising a member selected from the group consisting of poly(.alpha.-hydroxy acids) and poly(ethylene carbonates) and (ii) a hydrophilic B polymer block comprising a polyethylene glycol. Prior to use the liquid is maintained at a temperature below the reverse gelation temperature of the block copolymer.

Abstract: Peptide/protein biodegradable drug delivery devices are prepared as microspheres without the use of solvents by a polymer melt process. A melt of thermostable polypeptides and an appropriate low melting block copolymer mixture is prepared and dispersed in an appropriate fluid medium such as air, water or an immiscible organic fluid without using any organic solvent to form microdroplets. The fluid medium is cooled to solidify the microdroplets into microspheres and then collected and purified or further processed as drug delivery devices. These biodegradable microspheres are suitable as implantable or injectable pharmaceutical formulations. Following administration as solid microspheres into the body of a warm blooded animal, the formulations absorb water from the body to form a hydrogel from which the polypeptide is released continuously over an extended period of time.

Abstract: Terpolymers which are sensitive to pH and temperature are useful carriers for conducting bioactive agents through the gastric juices of the stomach in protected form. Such terpolymers swell at the higher physiologic pH of the intestinal tract causing release of the bioactive agents into the intestine. The terpolymers are linear and are made up of 35 to 99 wt % of a temperature sensitive component, which imparts to the terpolymer LCST (lower critical solution temperature) properties below body temperatures, 1 to 30 wt % of a pH sensitive component having a pK.sub.a in the range of from 2 to 8 which functions through ionization or deionization of carboxylic acid groups to prevent the bioactive agent from being lost at low pH but allows bioactive agent release at physiological pH of about 7.4 and a hydrophobic component which stabilizes the LCST below body temperatures and compensates for bioactive agent effects on the terpolymers.