Diacerein (Diacetylrhein, DCN) is anthraquinone derivatives used in the curing of osteoarthritis but, its usage is restricted due to its very poor solubility and wettability which result in bioavailability variation. The objective of this work was to design fast dissolving tablets (FDTs) of DCN solid dispersion. Solid dispersions (SDs) and physical mixtures (PMs) were prepared with PEG4000, Polyvinylpyrolidone K25 (PVPK25) and Sorbitol. SD formation increased the dissolution rate of DCN compared to PM; this demonstrates that the improvement of dissolution rate with SD can be due to physical change in drug crystal which was confirmed by thermal analysis. SD with Sorbitol was selected for the preparations of FDTs. Seven formulations were prepared by direct compression method using different concentrations of crospovidone as superdisintegrant and camphor as subliming agent. Pre and post compression evaluation were carried for powder blend and the prepared FDTs, respectively. F7 (composed of 120 mg Crospovidone, 45 mg camphor, 200 mg SD containing 50 mg DCN, 7.5 mg aspartame, 2.5 mg menthol, 2.5 mg Magnesium stearate and 22.5 mg lactose) showed the shortest disintegration time and the highest dissolution rate and it was selected for further investigation. Kinetic studies of the in-vitro release results showed that F7 followed first-order kinetics. Stability studies conducted for formula F7 showed good stability upon storage at 30oC/75% RH and 40oC/75% RH for 12 weeks.
Key words: Diacerein, solid dispersion, polyethylene glycol, polyvinylpyrrolidone, sorbitol, fast dissolving tablets.
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