Improved dissolution rate of indomethacin by adsorbents.

Samples of indomethacin and kaolin or microcrystalline cellulose (Avicel) were prepared by solvent deposition or simple blending methods. Dissolution rates of these samples were studied. The surface adsorption of indomethacin on the studied adsorbents was shown to improve the dissolution rate of the drug in water. The solvent-deposited samples of indomethacin on kaolin or Avicel in the ratio 1:4 released 25% of the drug at 34 or 60 min, respectively (t25%), while 25% of the pure drug was released at 140 min. Meanwhile, the t25% of the corresponding drug-adsorbent simple blends were 108 and 110 min, respectively. The effect of addition of polyvinyl pyrrolidone (PVP) as a third component to indomethacin-adsorbent was studied and showed further improvement in in vitro availability of the drug-kaolin adsorbents.