Inline UV/Vis spectroscopy as PAT tool for hot-melt extrusion

  • Jens Wesholowski
  • Sebastian Prill
  • Andreas Berghaus
  • Markus Thommes
Original Article


Hot-melt extrusion on co-rotating twin screw extruders is a focused technology for the production of pharmaceuticals in the context of Quality by Design. Since it is a continuous process, the potential for minimizing product quality fluctuation is enhanced. A typical application of hot-melt extrusion is the production of solid dispersions, where an active pharmaceutical ingredient (API) is distributed within a polymer matrix carrier. For this dosage form, the product quality is related amongst others to the drug content. This can be monitored on- or inline as critical quality attribute by a process analytical technology (PAT) in order to meet the specific requirements of Quality by Design. In this study, an inline UV/Vis spectrometer from ColVisTec was implemented in an early development twin screw extruder and the performance tested in accordance to the ICH Q2 guideline. Therefore, two API (carbamazepine and theophylline) and one polymer matrix (copovidone) were considered with the main focus on the quantification of the drug load. The obtained results revealed the suitability of the implemented PAT tool to quantify the drug load in a typical range for pharmaceutical applications. The effort for data evaluation was minimal due to univariate data analysis, and in combination with a measurement frequency of 1 Hz, the system is sufficient for real-time data acquisition.


Inline measurement Process analytical technology Process monitoring Quality by Design Twin screw extrusion UV/Vis spectroscopy 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflicts of interest.


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Copyright information

© Controlled Release Society 2018

Authors and Affiliations

  • Jens Wesholowski
    • 1
  • Sebastian Prill
    • 1
  • Andreas Berghaus
    • 2
  • Markus Thommes
    • 1
  1. 1.Institute of Solids Process EngineeringTU Dortmund UniversityDortmundGermany
  2. 2.ColVisTec AGBerlin–AdlershofGermany

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