Optimization and characterization of novel sustained release supermicro-pellet based dry suspensions that load dexibuprofen

Traditional dosage forms of dexibuprofen extremely limit their clinical applications because of the bitter taste and the frequent drug administration caused by the relatively short half-life of the drug. This study aims to design novel sustained release (SR) supermicro-pellet based dry suspensions that load dexibuprofen, and also optimize the formulations in terms of morphology, release rate, flowability, and physicochemical stability of dosage forms. Drug-loaded pellets were prepared by using a bottom spray fluid bed coating technique using microcrystalline cellulose supermicro-pellets as the core and PVP K30 or Poloxamer 188 as the binder. The drug-loaded pellets were further coated with Kollicoat SR 30D to form SR pellets. The optimal SR dry suspensions are composed of SR pellets, diluent granules, and suspending agents. PVP K30- and Poloxamer 188-based SR pellets release the drug molecules in a SR manner over 8 h and show a high release profile for Poloxamer 188-based pellets. The drug release profile is not affected by the rotation speed of the paddle but shows a distinct pH-responsive behavior. The physical property of dexibuprofen has been changed during the preparation process. The SR dry suspensions (F5, with high amount of xanthan gum in suspending agents and low amount of poloxamer 188 in diluent granules) show high physical stability with the sedimentation rate of 0.8 (Hu/H) within 5 min and good flowability with the angle of repose (θ) at 27°. Low content variations were observed with a value of A+1.80SD ≤ 15, and no significant change was found in the drug content under high humidity and strong light. In conclusion, novel SR supermicro-pellet based dry suspensions have been successfully prepared, and the optimal formulation shows excellent SR, good flowability, content uniformity, and physicochemical stability.