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Updated: Jul 4, 2026
08:04
Preparation of Functional Silica Using a Bioinspired Method
Published on: August 1, 2018
Precipitated silica as flow regulator.
Anne-Kathrin Müller1, Joanna Ruppel, Claus-Peter Drexel
1Pharmaceutical Technology, Institut of Pharmacy and Food Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Summary
Flow regulators, like amorphous silica, improve powder flow in pharmaceuticals by reducing attractive forces. Their effectiveness depends on how well they cover host particles, impacting powder blend tensile strength.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
- Powder Technology
Background:
- Flow regulators are crucial additives in solid pharmaceutical formulations to enhance powder flowability.
- Amorphous silica is commonly used, with properties like particle size and bond strength influencing its efficacy.
- Flow regulators function by adsorbing onto host particles, increasing surface roughness and reducing Van-der-Waals forces.
Purpose of the Study:
- To investigate the impact of different amorphous silicon dioxide types on powder flowability.
- To correlate the flow regulating potency of silica with its surface coverage and fragmentation.
- To understand the relationship between blending time, silica fragmentation, and powder mixture tensile strength.
Main Methods:
- Binary powder mixtures of corn starch and various amorphous silicon dioxide (fumed and precipitated silica) were prepared.
- Blending was performed using a Turbula mixer over a defined time period.
- Flowability was assessed by measuring the tensile strength of the powder mixtures over time.
Main Results:
- The effectiveness of silica flow regulators varied based on their ability to cover host particle surfaces.
- A reduction in tensile strength of the powder mixtures correlated with increased fragmentation of the flow regulator.
- Different silica types exhibited distinct flow regulating potencies, linked to their desagglomeration tendencies.
Conclusions:
- The rate and extent of surface coverage by silica particles significantly influence their flow regulating potency.
- Silica fragmentation during blending is a key factor in improving powder flowability.
- Understanding silica properties is essential for optimizing pharmaceutical powder flow and formulation.
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