ABSTRACT
Producing stable nanocrystals confined to porous excipient media is a desirable way to increase the dissolution rate and improve the bioavailability of poorly water soluble pharmaceuticals. The poorly soluble pharmaceutical fenofibrate was crystallized in controlled pore glass (CPG) of 10 different pore sizes between 12 nm and 300 nm. High drug loadings of greater than 20 wt% were achieved across all pore sizes greater than 20 nm. Nanocrystalline fenofibrate was formed in pore sizes greater than 20 nm and showed characteristic melting point depressions following a Gibbs-Thomson relationship as well as enhanced dissolution rates. Solid-state Nuclear Magnetic Resonance (NMR) was employed to characterize the crystallinity of the confined molecules. These results help to advance the fundamental understanding of nanocrystallization in confined pores.
ABSTRACT
Crystallization in rigid confinement is a promising method to obtain organic molecular nanocrystals. However, the crystallization behavior and the related characterization methods are not well studied. Here we present a systematic study of the nucleation of organic molecular nanocrystals in rigid pores. Four different compounds were studied, ibuprofen, fenofibrate, griseofulvin, and indomethacin, which range from simple to complex molecules. Solid-state Nuclear Magnetic Resonance (NMR) was employed to analyse the structure of these compounds inside pores which are difficult to characterize by other analytical methods. We successfully demonstrated the production of nano-crystalline ibuprofen, fenofibrate and griseofulvin in porous silica particles with ~ 40 nm pores. These nanocrystals showed significant enhancement in dissolution rates. These results help advance the fundamental understanding of nucleation under rigid confinement and may lead to potential applications in developing new formulations in the pharmaceutical industry.
