Influence of amorphous solid Dispersions of Paracetamol and PVP VA 64 on the thermoresponsive Behaviour of the Polymer

The dissolution of spray-dried amorphous solid dispersions consisting of paracetamol and PVP VA 64 at room temperature leads to the formation of different systems, depending on the drug/polymer ratio. Aqueous systems at room temperature with poor paracetamol/PVP VA 64 ratio are transparent solutions, while higher drug loads lead to phase separation of the solution. PVP VA 64 is known as thermoresponsive polymer. The aim of the study was to investigate the dissolution behaviour of these amorphous solid dispersions in water and their influence on the thermoresponsive behaviour of this polymer. Therefore, the demixing temperature was determined using DSC, since a change in the system constitutes an endothermic process. It could be shown that PVP VA 64 has lower critical solution temperature (LCST) behaviour around 70 °C, which decreases with increasing content of paracetamol due to the complex formation between the polymer and paracetamol.