Thermal Properties and Recrystallization Tendencies of Pharmaceutical Amorphous Solid Dispersions using a Thin Film Model

Abstract

Oral dosage formulation is a widely used drug formulation method that offers favorable economics and high patient adherence. For optimal performance in oral solid dosage it is desirable to have high aqueous solubility, however many drugs in the development pipeline show poor solubility. Amorphous solid dispersions (ASDs) represent one technology that can be used to enhance the solubility of small drug molecules. This thesis studies ASDs consisting of cannabidiol (CBD) and various FDA approved polymers in a thin film model prepared via spin coating. Thin films of a controlled film thickness are prepared and characterized. The film thickness, glass transition temperature, and recrystallization tendency of the thin films are characterized using ellipsometry, differential scanning calorimetry (DSC), and polarized light microscopy (PLM). Thin films offer a high throughput method that requires less raw material than standard methods for characterizing and screening ASDs for candidates that can be further analyzed for use in oral formulations. The polymer PVP-VA is shown as a clear candidate for an ASD containing CBD as it strongly prevented the recrystallization of CBD and showed the highest glass transition temperature indicating that this dispersion shows a longer shelf life than dispersions made with other polymers.