Use of synthetic inorganic nanoparticles as carriers for ophthalmic and otic drugs

Abstract

The use of nanoparticles of inorganic materials (e.g., synthetic smectite clays) in ophthalmic and otic pharmaceutical compositions is described. The nanoparticles are utilized as biologically inert carriers or depots for ophthalmic and otic drugs. The nanoparticles may also be utilized to modify the rheological properties of the compositions, so as to enhance the viscosity or flow characteristics of the compositions and/or increase the retention time of the compositions in the eye or ear.

1 . Use of synthetic inorganic nanoparticles as carriers for ophthalmic or otic drugs.  
     
     
         2 . A method of delivering a drug to the eye or ear, which comprises utilizing synthetic inorganic nanoparticles as carriers for the drug.  
     
     
         3 . An ophthalmic or otic pharmaceutical composition comprising a therapeutically effective amount of an ophthalmic or otic drug and an amount of synthetic inorganic nanoparticles sufficient to carry the drug.  
     
     
         4 . A composition according to  claim 3  wherein the nanoparticles have: (a) particle dimensions less than 100 nm, but greater than 1 nm, with a standard deviation of the distribution of less than 10%; (b) surface areas ranging from 30 to 1000 m 2 /g; and (c) an overall negative surface charge at a pH in the range of 6.0 to 7.8.  
     
     
         5 . A composition according to claims  3  or  4 , wherein the nanoparticles are formed form a synthetic hydrous clay  
     
     
         6 . A composition according to  claim 5 , wherein the synthetic hydrous clay is a smectite clay.  
     
     
         7 . A composition according to claims  3  or  4 , wherein the nanoparticles are selected from the group consisting of zealites, hydrotalcite, silica, aluminum oxide, cerium oxide, titanium oxide and zinc oxide.  
     
     
         8 . A composition according to any one of  claims 3  to  7 , wherein the concentration of the nanoparticles in the composition is 0.000001 to 10 w/v %.