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Minimum rotation speed to prevent coning phenomena in compendium paddle dissolution apparatus
Mizuki Higuchi1, Yasuo Yoshihashi1, Katsuhide Tarada1
1Faculty of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan.
Summary
The Zwietering equation effectively predicts the disappearance of coning phenomena during dissolution testing in paddle apparatus. This study optimized the equation for specific vessel geometries, improving its applicability.
Area of Science:
- Pharmaceutical Sciences
- Chemical Engineering
- Physical Chemistry
Background:
- Coning phenomena can impact dissolution testing accuracy.
- The Zwietering equation is a predictive model for mixing and suspension.
- Understanding coning is crucial for reliable dissolution studies.
Purpose of the Study:
- To evaluate the Zwietering equation's applicability to coning phenomena.
- To determine the minimum speed for coning disappearance (NCrpm) in a specific apparatus.
- To optimize Zwietering equation parameters for coning prediction.
Main Methods:
- Experimental determination of NCrpm across various particle and fluid properties.
- Optimization of particle size, relative density, and kinematic viscosity exponents.
- Utilizing a compendium paddle apparatus with a round-bottom unbaffled vessel.
Main Results:
- Optimized exponents for the Zwietering equation were determined.
- Particle size and relative density exponents aligned with existing data.
- A significantly different kinematic viscosity exponent was observed.
- The derived equation accurately predicted coning occurrence (r²=0.98, error=12rpm).
Conclusions:
- The Zwietering equation is applicable to predicting coning phenomena in the studied paddle apparatus.
- The optimized equation provides a reliable method for estimating coning.
- Differences in the kinematic viscosity exponent highlight the importance of vessel geometry.
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