Effect of disintegrants with different hygroscopicity on dissolution of Norfloxacin/Pharmatose DCL 11 tablets

This paper reports the effect of disintegrant hygroscopicity on dissolution of tablets obtained by compression at 85 MPa of mixtures of Norfloxacin and different proportions of a disintegrant (Starch 1500, PVP XL 10 or Croscarmellose sodium) and a diluent (Pharmatose DCL 11). Dissolution behavior was evaluated according to USP 23, apparatus 2 (paddle) at 50 rpm and using 750 ml acetate buffer solution of pH 4, at 37 degrees C, as medium. Norfloxacin added of increasing proportions, in a given range, of each disintegrant or the diluent increased the drug dissolved. Addition of increasing proportions of Pharmatose DCL 11 to Norfloxacin with 5% of the high hygroscopic Starch 1500 reduced the dissolution improvement effect of Pharmatose DCL 11. Addition of 5% Pharmatose DCL 11 to tablets of the middle hygroscopic Croscarmellose sodium and Norfloxacin slightly reduced the Croscarmellose sodium dissolution promoting effect, while addition of 15% Pharmatose DCL 11 to tablets of the low hygroscopic PVP XL 10 and Norfloxacin showed no inhibition but potentiated substantially the dissolution of Norfloxacin. These effects were attributed to competition for the available water in the tablet and to different water consume, for dissolution or hydration, by the diluent and the disintegrants.