[Preparation of sustained-release nitrendipine microspheres with a solid dispersed structure in liquid system].
OBJECTIVE
To prepare the sustained-release nitrendipine microspheres with a solid dispersed structure in liquid system.


METHODS
The sustained-release nitrendipine microspheres with a solid dispersed structure was prepared in liquid system by combining spherical crystallization technique and solvent deposition method in one step. The resultant microspheres were evaluated for the recovery, micromeritc properties, incorporation efficiency. The factors of effect on the formation and the release rate of microspheres were also investigated.


RESULTS
The recovery of microspheres (280-900 microns) was more than 70% and the bulk density was around 0.7 kg.L-1. The incorporation efficiency always exceeded 95%. The formation of microspheres was mainly affected by the amount of bridging liquid and the emulsifying agents in poor solvent. The release rate of nitrendipine from the microspheres could be controlled as desired by adjusting the ratio of talc to Eudragit RS PO in the formulation.


CONCLUSIONS
The presented method was suitable for preparing sustained-release microspheres of a water insoluble drug.
Yang
Ming-shi
MS
Department of Pharmaceutics, School of Pharmaceutical Science, Shenyang Pharmaceutical University, Shenyang 110016, China.
Cui
Fu-de
FD
Yang
He
H
Gao
Peng
P
Yue
Peng
P
Wang
Liang
L
Fan
Yu-ling
YL
D003692:Delayed-Action Preparations; D004337:Drug Carriers; D008863:Microspheres; D009568:Nitrendipine / Q000008:administration & dosage*; D010316:Particle Size; D013678:Technology, Pharmaceutical / Q000379:methods*
D003692:Delayed-Action Preparations; D004337:Drug Carriers; D009568:Nitrendipine