Miscibility studies of indomethacin and Eudragit® E PO by thermal, rheological, and spectroscopic analysis.

The objective of this study is to understand the underlying mechanisms responsible for the superior stability of indomethacin (INM)-Eudragit® E PO (E PO) system by exploring the miscibility and intermolecular interactions through the combination of thermal, rheological, and spectroscopic analysis. The zero shear-rate viscosity drops monotonically with the increase of INM concentration at 145 °C, suggesting that E PO and INM form a solution and the small molecular drug acts as a plasticizer. Flow activation energy was calculated from the viscosity data at different temperature.

Rheological study of the mixture of acetaminophen and polyethylene oxide for hot-melt extrusion application.

There is a growing interest of extrusion drug and polymer together to manufacture various solid dosages. In those cases, the drug's release profiles are greatly affected by the miscibility of two materials. The goal of this study is to test the drug's solubility in molten polymer and obtain the mixture's rheological properties for the purpose of optimizing the extrusion process.

Determination of acetaminophen's solubility in poly(ethylene oxide) by rheological, thermal and microscopic methods.

A drug's solubility in a polymeric excipient is an important parameter that dictates the process window of hot-melt extrusion (HME) and product stability during storage. However, it is rather challenging to experimentally determine the solubility and there is very few published work in this field. In this study, the solubility of a model drug acetaminophen (APAP) in a pharmaceutical grade polymer poly(ethylene oxide) (PEO) at HME processing temperature was measured utilizing rheological analysis, hot-stage microscopy and differential scanning calorimetry (DSC).