Correlation of excipient properties with optimal drug load in eutectic mixtures from polyethylene glycol stearates and fenofibrate

A simple way to increase the dissolution rate of a poorly water-soluble active pharmaceutical ingredient (API) is to minimize its particle size. The development of eutectics is a method of minimizing the API particle size without the need for grinding and the handling of poorly flowing powders. At their eutectic composition, molten mixtures containing a water-soluble crystalline excipient, such as polyethylene glycol, and a poorly water-soluble API may form a finely dispersed solid system during recrystallization [1]. On contact with water, the finely dispersed API crystals are released and dissolve with an increased rate due to the increase in specific surface area. However, beyond the eutectic concentration, the API forms larger segregates. Phase diagrams provide information about the eutectic concentration and also about the thermal properties of the eutectic and are therefore very helpful when processing eutectics. Polyethylene glycol stearates are self-dispersible excipients, which are able to solubilize poorly water-soluble APIs. They are available with different polyethylene glycol chain lengths and thus provide a variety of options for the development of self-dispersible eutectics. The current study compares various eutectics containing polyethylene glycol stearates differing in polyethylene glycol chain length or different solid polyethylene glycols and the poorly soluble API fenofibrate. The study provides information on the correlation of the phase behavior of the eutectic mixtures investigated with the thermal properties of the excipients used. Furthermore, it offers insights into the possibilities for optimizing the drug load of eutectics containing polyethylene glycol stearates and fenofibrate.