Powder for oral suspension containing lamotrigine

Abstract

This document discloses a powder formulation of lamotrigine for oral administration. Also disclosed is a suspension of lamotrigine and a method of treating diseases.

1 - 20 . (canceled) 
     
     
         21 . A powder formulation suitable for reconstitution with a pharmaceutically acceptable carrier to form a stable suspension, wherein the powder formulation comprises a powdered mixture of lamotrigine or a pharmaceutically acceptable salt thereof and xanthan gum,
 wherein the ratio between the lamotrigine or pharmaceutically acceptable salt thereof and the xanthan gum ranges from 20:1 to about 1:5 by weight,   and wherein the suspension provides a sedimentation volume ratio of more than about 0.8 for at least 10 hours.   
     
     
         22 . The powder formulation of  claim 21 , wherein less than about 5% of the lamotrigine or pharmaceutically acceptable salt thereof is converted to its hydrate form within about 24 hours after the powder formulation is reconstituted into the suspension. 
     
     
         23 . The powder formulation of  claim 21 , wherein less than about 0.5% of the lamotrigine or the pharmaceutically acceptable salt thereof decomposes within about 24 hours after the powder formulation is reconstituted into the suspension. 
     
     
         24 . The powder formulation of  claim 21 , wherein the ratio between the lamotrigine or pharmaceutically acceptable salt thereof and the xanthan gum ranges from 15:1 to about 1:5 by weight. 
     
     
         25 . The powder formulation of  claim 21 , wherein the suspension is homogeneous and is achieved within about 60 seconds after the powder formulation is reconstituted with water. 
     
     
         26 . The powder formulation of  claim 21 , wherein the suspension prepared from the powder formulation provides a release of the lamotrigine or pharmaceutically acceptable salt thereof bioequivalent to Lamictal tablet having the same dose of lamotrigine. 
     
     
         27 . The powder formulation of  claim 21 , further comprising a lubricant selected from the group consisting of silicon dioxide, magnesium stearate, talc, and sodium stearyl fumarate in about 0.1% to about 5% by weight of the powder formulation. 
     
     
         28 . The powder formulation of  claim 21 , further comprising a diluent selected from the group consisting of sucrose, dextrose, mannitol, sorbitol, maltitol, starch, lactose, microcrystalline cellulose, and any combination thereof in about 10% to about 90% by weight of the powder formulation. 
     
     
         29 . The powder formulation of  claim 21 , further comprising a buffering agent selected from the group consisting of sodium citrate, citric acid, fumaric acid, tartaric acid, potassium citrate, sodium bicarbonate, potassium bicarbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, and potassium dihydrogen phosphate. 
     
     
         30 . The powder formulation of  claim 21 , wherein the xanthan gum is present in the powder formulation from about 0.5 wt % to 5 wt %. 
     
     
         31 . A powder formulation suitable for reconstitution with a pharmaceutically acceptable carrier to form a stable suspension, wherein the powder formulation comprises a powdered mixture of lamotrigine or a pharmaceutically acceptable salt thereof and a suspending agent,
 wherein the suspending agent is selected from a cellulosic derivative, a polysaccharide, an acrylic acid copolymer, or a combination thereof,   wherein the ratio between the lamotrigine or pharmaceutically acceptable salt thereof and the suspending agent ranges from 20:1 to about 1:5 by weight,   and wherein the suspension provides a sedimentation volume ratio of more than about 0.8 for at least 10 hours.   
     
     
         32 . The powder formulation of  claim 31 , wherein the suspending agent is xanthan gum, hydroxypropyl methylcellulose (HPMC), polyacrylic acid, or a combination thereof. 
     
     
         33 . The powder formulation of  claim 31 , wherein the suspending agent is present in the powder formulation from about 0.5 wt % to 5 wt %. 
     
     
         34 . The powder formulation of  claim 31 , wherein the ratio between the lamotrigine or pharmaceutically acceptable salt thereof and the suspending agent ranges from about 15:1 to about 1:5 by weight. 
     
     
         35 . The powder formulation of  claim 31 , wherein less than about 5% of the lamotrigine or pharmaceutically acceptable salt thereof is converted to its hydrate form within about 24 hours after the powder formulation is reconstituted into the suspension. 
     
     
         36 . The powder formulation of  claim 31 , wherein less than about 0.5% of the lamotrigine or the pharmaceutically acceptable salt thereof decomposes within about 24 hours after the powder formulation is reconstituted into the suspension. 
     
     
         37 . The powder formulation of  claim 31 , wherein the suspension prepared from the powder formulation provides a release of the lamotrigine or pharmaceutically acceptable salt thereof bioequivalent to Lamictal tablet having the same dose of lamotrigine. 
     
     
         38 . The powder formulation of  claim 31 , further comprising a lubricant selected from the group consisting of silicon dioxide, magnesium stearate, talc, and sodium stearyl fumarate in about 0.1% to about 5% by weight of the powder formulation. 
     
     
         39 . The powder formulation of  claim 33 , further comprising a diluent selected from the group consisting of sucrose, dextrose, mannitol, sorbitol, maltitol, starch, lactose, microcrystalline cellulose, and any combination thereof in about 10% to about 90% by weight of the powder formulation. 
     
     
         40 . The powder formulation of  claim 33 , further comprising a buffering agent selected from the group consisting of sodium citrate, citric acid, fumaric acid, tartaric acid, potassium citrate, sodium bicarbonate, potassium bicarbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, and potassium dihydrogen phosphate.