Investigating the effect of the solvent on the physical structure and phase behavior of amorphous solid dispersions manufactured with spray drying
Over the past years, the number of poorly soluble drugs has significantly increased, resulting in low and variable oral bioavailability. To address this problem, a promising strategy is to disperse the drug at the molecular level in an inert polymeric carrier, which is known as an amorphous solid dispersion (ASD). One of the most commonly used manufacturing methods for ASDs is spray drying. Several commercial ASD formulations have been developed using spray drying, however the number of commercial products is still limited. A possible reason for this is the existence of remaining knowledge gaps. For example, the influence of the solvent, used to dissolve the components, remains a vastly underexplored parameter. There are indications that point out that the solvent could have a significant impact on the phase behavior/physical structure and stability of the formulation. Therefore, this PhD research aims at the elucidation of the effect of the solvent on the physical structure of the ASD. The prospected advantage of this knowledge is that the confidence in spray drying as a manufacturing method will increase, and additionally this will establish ASDs as a preferred enabling strategy as well, increasing the number of ASD formulations on the market and limiting the attrition rates of new molecular entities due to poor physicochemical properties. This will reduce the costs for the pharmaceutical companies and will bring new drugs to the market which would otherwise be discarded.