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Viscoelastic and Deformation Characteristics of Structurally Different Commercial Topical Systems
Maryam Dabbaghi1, Sarika Namjoshi1, Bhavesh Panchal1
1Therapeutics Research Group, The University of Queensland Diamantina Institute, Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia.
Pharmaceutics
|September 28, 2021
Summary
Topical product rheology, including viscosity and yield stress, is key for pharmaceutical equivalence. Creams and gels exhibit distinct shear responses, impacting their microstructure and deformation properties.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
- Rheology
Background:
- Rheological properties of topical products influence pharmaceutical, therapeutic, and perceptive equivalence.
- Understanding shear response is crucial for characterizing product quality and stability.
Purpose of the Study:
- To characterize the rheological behavior of commercial creams and gels under controlled shear conditions.
- To assess if the products meet Critical Quality Attribute criteria for viscosity and yield stress.
Main Methods:
- Dynamic rheological characterization in steady-state flow and oscillatory modes.
- Analysis of zero-shear viscosity (η₀), yield stress (τ₀), storage modulus (G'), and loss modulus (G″).
Main Results:
- Most products met Critical Quality Attribute criteria for high viscosity and yield stress, except for cream C3, which showed lotion-like behavior.
- All formulations exhibited viscoelastic solid behavior (G' > G″).
- Creams showed more rapid G' to G″ transitions (brittle deformation) compared to gels (gradual polymer network disentanglement).
Conclusions:
- Rheological analysis confirms product quality, stability, and microstructure.
- Distinct rheological profiles differentiate creams (inelastic) from gels (flexible).
- Shear response characterization aids in understanding topical product performance and equivalence.
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