Abstract: The present invention relates to a block copolymer formed by coupling the following components with each other, as well as a hydrogel composition comprising the block copolymer and a hydrogel formed from the composition: (a) a copolymer of a polyethylene glycol (PEG)-based compound with a biodegradable polymer; and (b) a sulfonamide-based oligomer. The inventive block copolymer shows the sol-gel transition behavior sensitive to changes in not only temperature but also pH. Thus, the inventive block copolymer overcomes the shortcomings of temperature-sensitive copolymers, form a more strong and stable hydrogel, and is stable in vivo. Accordingly, the inventive block copolymer can be used in various applications in the medical and drug delivery fields.

Abstract: Mixed micelles containing poly(L-histidine)-poly(ethylene glycol) block copolymer and poly(L-lactic acid)-poly(ethylene glycol) block copolymer are a pH-sensitive drug carrier that release the drug in an acidic microenvironment, but not in the blood. Since the microenvironment of solid tumors is acidic, these mixed micelles are useful for treating cancer, including those cancers exhibiting multidrug resistance. Targeting ligands, such as folate, can also be attached to the mixed micelles for enhancing drug delivery into cells. Methods of treating a warm-blooded animal with such a drug are disclosed.

Abstract: Compositions and methods for stabilization and controlled release of ionic biopharmaceuticals are disclosed. Illustrative compositions according to the present invention include polyelectrolyte-PEG diblock copolymers complexed by ionic bonds with the ionic biopharmaceuticals. Additional illustrative compositions include microspheres encapsulating polyelectrolyte-PEG diblock copolymers complexed by ionic bonds with the ionic biopharmaceuticals. A method of delivering a biopharmaceutical to a person in need thereof involves administering microspheres that encapsulate biopharmaceutical/polyelectrolyte-PEG diblock copolymer complexes.

Abstract: Drug delivery compositions for specific delivery of a drug to a tumor are described. These compositions include a core for sequestering the drug and a shell to which a ligand is attached for delivery of a drug to target cells. Since normal cells may also be targeted by the ligand, the compositions embed the ligand in the shell until the localized conditions surrounding the tumor cause the ligand to be displayed on the surface of the shell. One composition exhibits shrinkage of the shell at tumor pH, whereas another composition exhibits extension of the ligand at tumor pH. Still another composition causes the ligand to be exhibited at an elevated temperature.

Abstract: Mixed micelles containing poly(L-histidine)-poly(ethylene glycol) block copolymer and poly(L-lactic acid)-poly(ethylene glycol) block copolymer are a pH-sensitive drug carrier that release the drug in an acidic microenvironment, but not in the blood. Since the microenvironment of solid tumors is acidic, these mixed micelles are useful for treating cancer, including those cancers exhibiting multidrug resistance. Targeting ligands, such as folate, can also be attached to the mixed micelles for enhancing drug delivery into cells. Methods of making poly(L-histidine), synthetic intermediates, and block copolymers are also described.