Bunjes Heike, Koch Michel H J, Westesen Kirsten
Friedrich-Schiller-Universität Jena, Institute of Pharmacy, Department of Pharmaceutical Technology, Lessingstrasse 8, 07743 Jena, Germany.
J Pharm Sci. 2003 Jul;92(7):1509-20. doi: 10.1002/jps.10413.
The crystallization temperature and polymorphism of tripalmitin nanoparticles in colloidal dispersions prepared by melt-homogenization and stabilized with different pharmaceutical surfactants (sodium glycocholate, sodium oleate, tyloxapol, Solutol HS 15, Cremophor EL) and their combinations with soybean phospholipid (Lipoid S100) were investigated to establish the influence of the emulsifiers on these parameters. There were no major effects on the crystallization temperature but remarkable differences in the time-course of polymorphic transitions after crystallization of the triglyceride particles indicate interaction between the surfactant layer and the triglyceride matrix. The metastable alpha-modification was most stable in dispersions solely stabilized with glycocholate. Upon fast cooling from the melt, these dispersions form an uncommon type of alpha-modification that displays only a very weak small-angle reflection indicating poor ordering between triglyceride layers. Slow crystallization of these glycocholate-stabilized nanoparticles yields the usual alpha-form. Electron microscopic investigations reveal that, in both cases, the particles in the alpha-modification are less anisometric than those of the stable beta-form. These results indicate that major rearrangements still may take place in solid lipid nanoparticles after recrystallization.
研究了通过熔融均质法制备并用不同药用表面活性剂（甘氨胆酸钠、油酸钠、聚乙氧基月桂醇、聚乙二醇单硬脂酸酯HS 15、聚氧乙烯蓖麻油EL）及其与大豆磷脂（Lipoid S100）的组合稳定的胶体分散体中三棕榈酸甘油酯纳米颗粒的结晶温度和多晶型，以确定乳化剂对这些参数的影响。对结晶温度没有重大影响，但甘油三酯颗粒结晶后多晶型转变的时间进程存在显著差异，这表明表面活性剂层与甘油三酯基质之间存在相互作用。亚稳α-晶型在仅用胆酸盐稳定的分散体中最稳定。从熔体快速冷却时，这些分散体形成一种不常见的α-晶型，其仅显示非常弱的小角反射，表明甘油三酯层之间的有序性较差。这些胆酸盐稳定的纳米颗粒缓慢结晶会产生常见的α-晶型。电子显微镜研究表明，在这两种情况下，α-晶型的颗粒比稳定的β-晶型颗粒的各向异性更小。这些结果表明，重结晶后固体脂质纳米颗粒中仍可能发生重大重排。
