Supercooled Smectic Nanoparticles

Figure 10.9. DSC heating and cooling curves (5°C/min) of cholesteryl myristate in the bulk and in colloidal dispersion (5% CM, 2% PVA PCS z-average 172 nm, PDI 0.09). With kind permission from Springer Science + Business Media Fharm. Res. Supercooled smectic nanoparticles A potential novel carrier system for poorly water soluble drugs, 21, (2004), 1834-1843, J Kuntsche et al. Abbreviations DSC differential scanning calorimetry, PVA polyvinyl alcohol, PCS Photon correlation spectroscopy, PDI Polydispersity index.

Electron microscopic investigations (cryo-TEM and freeze-fracture ) indicate that supercooled smectic nanoparticles have a nearly cylindrical particle shape in most cases. This is in agreement with the cylindrical shape of LDL when studied at room temperature where the LDL are in a liquid crystalline state. ... 

Compared to lyotropic LCNP the thermotropic mesophase-based supercooled smectic nanoparticles are in a still much more early stage of development. Although structural aspects of these nanoparticles are not quite as complex as with lyotropic LCNP and the physicochemical properties of these nanoparticles as well as the influencing parameters on the phase behavior have been studied in some detail yet much remains to be done for further optimization of the formulations in particular with regard to the stability of the nanoparticles against recrystallization. Furthermore, application related studies have to be performed, especially with a focus on parenteral drug delivery which was the main driving force for the development of these particles. 

Nanoparticles based on the supercooled smectic phase of cholesterol esters were introduced as a potential novel carrier system for lipophilic drugs. Due to the high viscosity of the smectic phase but mobility on the molecular level, advantages in... 

The high supercooling tendency of the smectic phase of cholesterol esters is the basis for the development of smectic nanoparticles from cholesterol esters that are crystalline solids in the bulk at... 

Stability of file Supercooled Smectic Phase and Influence of Hie Nanoparticle Compo on... 

As the supercooled smectic state is metastable, the recrystallization tendency of the nanoparticles during storage is of high interest. Due to its completely reversible phase behavior and favorable crystallization temperature in the colloidal state, cholesteryl myristate was used as model cholesterol ester for investigations of the recrystallization tendency and influencing parameters like particle size and stabilizer system. 

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