New multifunctional pharmaceutical excipient in tablet formulation based on citric acid-cyclodextrin polymer

A beta-cyclodextrin (beta-CD) polymer obtained by crosslinking beta-CD with citric acid in its water-insoluble (PCD-1) and soluble (PCD-S) forms was used as a multifunctional direct compression excipient for tablet designing. PCD-I powder was obtained after grinding the solid fraction through a 200 mu m grid. PCD-S powder was recovered after lyophilization or spray drying of the PCD-S aqueous solutions, eventually followed by a wet granulation step. Both PCD-I and PCD-S powders were characterized, separately and mixed in variable ratios, based on dynamic water vapor sorption, SEM, particle size distribution, tapped density, compressibility, and flowability. PCD-I and spray dried and lyophilized/wet granulated PCD-S, as well as the mixture PCD-I/PCD-S = 90/10, presented optimal free flowing characteristics. Then, PCD-1 or PCD-S powders - separately or mixed in variable ratios - were used for tablets preparation by direct compression without adding any other excipient (e.g. binder, lubricant, disintegrant etc). As PCD-I decreased, tablets resistance to crushing and disintegration time increased from 15 s to 15 min (against 30 min for beta-CD), showing the improved disintegrant functionality of PCD-I, that rapidly swelled once in contact with water. Finally, PCD was force-fed to Sprague-Dawley rats (2 g/kg) which were then observed during 14 days for any clinical signs of toxicity. (C) 2016 Published by Elsevier B.V.