Yuan Xiaoda, Sperger Diana, Munson Eric J
Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States.
Mol Pharm. 2014 Jan 6;11(1):329-37. doi: 10.1021/mp400498n. Epub 2013 Nov 27.
Solid-state NMR (SSNMR) (1)H T1 and T1ρ relaxation times were used to evaluate the miscibility of amorphous solid dispersions of nifedipine (NIF) and polyvinylpyrrolidone (PVP) prepared by three different methods: melt quenching in the typical lab setting, spray drying and melt quenching in the NMR rotor while spinning. Of the five compositions prepared by melt quenching in the lab setting, the 95:5 and 90:10 NIF:PVP (w:w) amorphous solid dispersions were not miscible while 75:25, 60:40, and 50:50 NIF:PVP dispersions were miscible by the (1)H T1ρ measurements. The domain size of the miscible systems was estimated to be less than 4.5 nm. Amorphous solid dispersions with composition of 90:10 NIF:PVP prepared by spray drying and melt quenching in the NMR rotor showed miscibility by (1)H T1ρ values. Variable-temperature SSNMR (1)H T1ρ relaxation measurements revealed a change in relaxation time at approximately 20 °C below Tg, suggesting increased molecular mobility above that temperature.
固态核磁共振（SSNMR）的（1）H T1和T1ρ弛豫时间用于评估通过三种不同方法制备的硝苯地平（NIF）与聚乙烯吡咯烷酮（PVP）的非晶态固体分散体的混溶性：在典型实验室环境中进行熔体淬火、喷雾干燥以及在旋转的核磁共振转子中进行熔体淬火。在实验室环境中通过熔体淬火制备的五种组合物中，95:5和90:10的NIF:PVP（重量比）非晶态固体分散体不混溶，而75:25、60:40和50:50的NIF:PVP分散体通过（1）H T1ρ测量显示为混溶。混溶体系的域尺寸估计小于4.5纳米。通过喷雾干燥和在核磁共振转子中进行熔体淬火制备的90:10 NIF:PVP组成的非晶态固体分散体通过（1）H T1ρ值显示出混溶性。变温固态核磁共振（1）H T1ρ弛豫测量显示，在低于玻璃化转变温度（Tg）约20°C时弛豫时间发生变化，表明在该温度以上分子流动性增加。
