A significant research focus in the pharmaceutical industry is on methods to improve drug uptake into the body by increased dissolution of poorly water soluble active pharmaceutical ingredients (APIs) or sustained drug release behavior. Control over the solubility of the API is possible through heterogenous crystallization or crystallization in confined nanopores, which enables the directed nucleation of specific API polymorphs. Gel phase crystallization allows the use of both these methods for producing higher efficacy APIs. Heterogeneous crystallization from particles within the gel provides a surface for nucleation and the porosity within the gel provides nanopores for confined homogenous nucleation. Here we use natural materials, cellulose nanocrystals (CNCs), that have a high surface area covered with readily-modified hydroxyl groups to form organogels that promote API crystallization into desired polymorphs for higher solubility or slower drug release behavior. CNCs presents with high strength, high stiffness and a large surface containing a high concentration of hydroxyl groups. This enables easy surface modification to display a variety of functional groups allowing significant control over nanocellulose interactions with other molecules. This provides the potential for highly tunable gels with interesting physical properties and surface chemistries, which can provide sites for crystallization or bind with drug molecules to act as a release inhibitor. We use CNC functionalization, such as carboxylation and esterification, to design water-free gel systems containing modified nanocellulose and crystallized pharmaceutical products. The high surface area of the nanocellulose provides a high concentration of interaction sites for cross-linking and gelation, which shows promise for the use of CNC organogels as supports for pharmaceutical crystallization, with an aim towards using the molecular interactions between nanocellulose and drugs to direct formation of desired polymorphs and crystal sizes, leading to flexibility for rational design of nanocellulose-drug composites.<br/>

Organogels of surface modified nanocellulose for applications in crystallizing pharmaceuticals

2019 Spring National Meeting

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