Rheological Analysis of L-HPC and Suitability for Continuous Manufacturing

The 12th APV PBP World Meeting took place from 28 – 31 March 2022 in Rotterdam. There was a poster section at the event where really interesting scientific posters were presented. Therefore we asked the presenting scientists if we could share their work in addition online with the Pharma Excipients community.

As many scientists send us their posters we already showed 12  posters of the PBP World Meeting 2022 Poster Session stepwise over the last weeks.

Shin-Etsu presented two posters during the PBP world meeting in Rotterdam.
This second poster was focusing on the rheological analysis of L-HPC (low substituted hydroxypropylcellulose) to determine the suitability of the existing grades in continuous manufacturing, especially to predict their feeding ability. A FT-4 powder rheometer was used to analyse the flow rate and shear cell.

See here the poster from Vanessa Havenith, Shin-Etsu:
(click on the poster to enlarge it)

Download the poster as PDF here: Rheological Analysis of L HPC and Suitability for Continuous Manufacturing

Introduction

The characterization of the powder flow using traditional methods like Carr’s index or flow through a funnel is as example insufficient to screen and predict the powder performances during the feeding step in a continuous manufacturing line, as the powders are undergoing several physical environments requiring different behavioral properties.

During the development of formulations designed for a continuous process, looking into multi-functional excipients has several advantages. Besides the final functions of the excipients, it allows for a reduction of feeders needed. To compare different excipients, the pharmaceutical industry is looking for test methods which aid in the understanding of powder flow and feeding processes. One of these devices is the FT-4 Powder Rheometer, a widely used device for understanding powder flow behavior in the context of feeding and continuous manufacturing. L-HPC having different particle sizes and shapes is an excellent candidate for taking first steps in rheology analysis. In this study, we demonstrate the flow properties of five different L-HPC grades measured with the FT-4 Powder Rheometer.

Materials and Methods

L-HPC (Low-Substituted HydroxyPropyl Cellulose) LH-11, LH-21, LH-31, LH-B1 and NBD-021 were sourced from Shin-Etsu Chemical Co., Ltd. The main differences between the powders are the particle size distribution and particle shapes. The chemical substitution level (HP-content) for each grade is 11%. The powder rheology of all L-HPC grades were measured with the FT4 Powder Rheometer. The methods we used in this study were mostly related to the feeding step and included stability and variable flow rate as dynamic methodology, and shear cell as shear methodology. Shear cell data is more process-relevant for high stress environments (where the powder is compressed) and most specifically for discharge from hoppers, silos and feeders. To explore and predict flow in lower stress applications the focus should be on lower stress techniques like the dynamic measurements.

Author
Vanessa Havenith
Shin-Etsu Tylose GmbH & Co. KG , Kasteler Str. 45, 65203 Wiesbaden, Germany, vanessa.havenith [at]setylose.com:

More information on the applications of Shin-Etsu polymers can be found under:https://www.setylose.com/en/knowledge-base/healthcare

See the first Shin-Etsu poster of the PBP World Meeting 2022 poster session here