Patent ID: 7799345

Claim:
A composition for injection through a needle into a host, consisting of: microparticles consisting essentially of naltrexone and a polymeric binder selected from the group consisting of poly(glycolic acid), poly-d,l-lactic acid, poly-l-lactic acid, copolymers of the foregoing, poly(aliphatic carboxylic acids), copolyoxalates, polycaprolactone, polydioxanone, poly(ortho carbonates), poly(acetals), poly(lactic acid-caprolactone), polyorthoesters, poly(glycolic acid-caprolactone), polyanhydrides, and polyphosphazines; and an injection vehicle, wherein said injection vehicle consists of water, a viscosity enhancing agent, a wetting agent, and a tonicity adjusting agent, and wherein said microparticles are suspended in said injection vehicle at a concentration of more than about 30 mg/ml and up to about 300 mg/ml to form a suspension, wherein a fluid phase of said suspension has a viscosity greater than 30 cp and less than 600 cp at 20° C., wherein the viscosity of said fluid phase of said suspension provides injectability of the composition into the host through a needle ranging in diameter from 18-22 gauge.