Biodegradable injectable nanoparticles

A nanoparticle or microparticle formed of a block copolymer consisting essentially of poly(alkylene glycol) and a biodegradable polymer selected from the group consisting of polyanhydrides, polyhydroxybutyric acid, polyorthoesters, polysiloxanes, polycaprolactone, poly(lactic-co-glycolic acid), poly(lactic acid), poly(glycolic acid) and copolymers prepared from the monomers of these polymers, wherein the biodegradable moieties of the copolymer are in the core of the resulting particle, and the poly(alkylene glycol) moieties are on the surface of the resulting nanoparticle or microparticle in an amount effective to decrease uptake of the nanoparticle or microparticle by the reticuloendothelial system, and wherein the copolymer is a diblock or multiblock copolymer comprising two or more poly(alkylene glycol) blocks.

A nanoparticle or microparticle formed of a block copolymer consisting essentially of poly(alkylene glycol) and a polymer selected from the group consisting of poly(lactic-co-glycolic acid), poly(lactic acid), and poly(glycolic acid), wherein the copolymer is blended with poly(lactic-co-glycolic acid) prior to forming the particle, and wherein the biodegradable moieties of the copolymer are in the core of the resulting particle, and the poly(alkylene glycol) moleties are on the surface of the resulting nanoparticle or microparticle in an amount effective to decrease uptake of the nanoparticle or microparticle. by the reticuloendothelial system.

A method for making a nanoparticle or microparticle with a core and a surface comprising:

• (i) preparing a solution of a block copolymer consisting essentially of poly(alkylene glycol) and biodegradable polymer selected from the group consisting of polyanhydride, polyhydroxybutyric acid, polyorthoesters, polysiloxanes, polycaprolactone, and copolymers prepared from the monomers of these polymers;
• and
• (ii) precipitating the polymer from a solvent system such that the biodegradable moleties of the copolymer are in the core of the resulting particle, and the poly(alkylene glycol) moieties are on the surface of the resulting nanoparticle or microparticle in an amount effective to decrease uptake of the nanoparticle or microparticle by the reticuloendothelial system.

A method for making a nanoparticle or microparticle with a core and a surface comprising:

• (i) preparing a solution of a block copolymer consisting essentially of poly(alkylene glycol) and biodegradable polymer selected from the group consisting of polyanhydride, polyhydroxybutyfic acid, polyorthoesters, polysiloxanes, polycaprolactone, poly(lactic-co-glycolic acid), poly(lactic acid), poly(glycolic acid) and copolymers prepared from the monomers of these polymers, and
• (ii) precipitating the polymer from a solvent system such that the biodegradable moleties of the copolymer are in the core of the resulting particle, and the poly(alkylene glycol) moieties are on the surface of the resulting nanoparticle or microparticle in an amount effective to decrease uptake of the nanoparticle or microparticle by the reticuloendothelial system,
• wherein the copolymer is a diblock or multiblock copolymer comprising two or more blocks of poly(alkylene glycol).

A method for making a nanoparticle or microparticle with a core and a surface comprising:

• (i) preparing a solution of a block copolymer consisting essentially of poly(alkylene glycol) and biodegradable polymer selected from the group consisting of poly(lactic-co-glycolic acid), poly(lactic acid), poly(glycolic acid) and copolymers prepared from the rrtonomers of these polymers, and
• (ii) precipitating the polymer from a solvent system such that the biodegradable moieties of the copolymer are in the core of the resulting particle, and the poly(alkylene glycol) moieties are on the surface of the resulting nanoparticle or microparticle in an amount effective to decrease uptake of the nanoparticle or microparticle by the reticuloendothelial system,
• wherein the copolymer is blended with poly(lactic-co-glycotic acid) prior to forming the nanoparticles or microparticles.

A method for delivering a substance to a patient comprising administering to the patient a composition comprising nanoparticles or microparticles comprising a therapeutic or detectable amount of a substance to be delivered to a patient in need thereof and a block copolymer consisting essentially of poly(alkylene glycol) and a biodegradable polymer selected from the group consisting of polyanhydride, polyhydroxybutyric acid, polyorthoesters, polysiloxanes, polycaprolactone, and copolymers prepared from the monomers of these polymers, wherein the biodegradable moieties of the copolymer are in the core of the resulting particle, and the poly(alkylene glycol) moieties are on the surface or the resulting particle in an amount effective to decrease uptake of the nanoparticle or microparticle by the reticuloendothelial system.