Sudden rise of crystal growth rate of nifedipine near Tg without and with polyvinylpyrrolidone

✍ Scribed by Hajime Ishida; Tian Wu; Lian Yu

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 268 KB
• Volume: 96
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.20925

✦ Synopsis

The crystal growth of nifedipine in the b polymorph has been measured from T g þ 50 to T g À 20 K, where T g ¼ 315 K is the glass transition temperature. A sudden 10-fold rise of growth rate was observed as the temperature decreased from above to below T g accompanied by a change of growth morphology. This is the same phenomenon reported by Oguni and coworkers [Hikima T, Adachi Y, Hanaya M, Oguni M. 1995. Phys Rev B 52:3900-3908] for other compounds of lower T g . The phenomenon persisted in the presence of 1% polyvinylpyrrolidone (PVP). The presence of 1% or 2% PVP had little effect on the growth rate near T g þ 50 K, but reduced the growth rate by 100-fold at T g þ 9 K. These kinetic features are relevant to predicting the stability of amorphous drugs. ß 2007