Design and evaluation of fast dissolving tablets of clonazepam

In the present work, fast dissolving tablets of clonazepam were prepared by direct compression method with a view to enhance patient compliance. Three super-disintegrants, viz., crospovidone, croscarmellose sodium and sodium starch glycolate in different ratios with microcrystalline cellulose (Avicel PH-102) along with directly compressible mannitol (Pearlitol SD 200) to enhance mouth feel. The prepared batches of tablets were evaluated for hardness, friability, drug content uniformity, wetting time, water absorption ratio and in vitro dispersion time. Based on in vitro dispersion time (approximately 13 s), three formulations were tested for the in vitro drug release pattern (in pH 6.8 phosphate buffer), short-term stability (at 40°/75% relative humidity for 6 mo) and drug-excipient interaction (IR spectroscopy). Among the three promising formulations, the formulation prepared by using 10% w/w of crospovidone and 35% w/w of microcrystalline cellulose emerged as the overall best formulation (t(50%) 1.8 min) based on the in vitro drug release characteristics compared to conventional commercial tablet formulation (t(50%) 16.4 min). Short-term stability studies on the formulations indicated that there were no significant changes in drug content and in vitro dispersion time (P<0.05).