Sudden rise of crystal growth rate of nifedipine near T(g) without and with polyvinylpyrrolidone.
The crystal growth of nifedipine in the beta polymorph has been measured from T(g) + 50 to T(g) - 20 K, where T(g) = 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) + 50 K, but reduced the growth rate by 100-fold at T(g) + 9 K. These kinetic features are relevant to predicting the stability of amorphous drugs.
Ishida
Hajime
H
School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
Wu
Tian
T
Yu
Lian
L
D002121:Calcium Channel Blockers / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D018360:Crystallography, X-Ray; D004355:Drug Stability; D005079:Excipients / Q000737:chemistry*; D007700:Kinetics; D009543:Nifedipine / Q000737:chemistry*; D044367:Phase Transition; D011205:Povidone / Q000737:chemistry*; D012995:Solubility; D013059:Spectrum Analysis, Raman; D044366:Transition Temperature
D002121:Calcium Channel Blockers; D005079:Excipients; D011205:Povidone; D009543:Nifedipine