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In vitro Digestion of Emulsions in a Single Droplet via Multi Subphase Exchange of Simulated Gastrointestinal Fluids
Published on: November 18, 2022
Rheological investigation of self-emulsification process
Shailesh V Biradar1, Ravindra S Dhumal, Anant Paradkar
1Department of Pharmaceutics, Bharati Vidyapeeth University, Poona College of Pharmacy, Erandwane, Pune 411 038, India.
Summary
The rheological properties of the intermediate liquid crystalline (LC) phase significantly impact self-emulsification. A weak, fragile LC phase in 30% I742 systems facilitates nanoemulsion formation, unlike other formulations.
Area of Science:
- Materials Science
- Physical Chemistry
- Colloid Science
Background:
- Self-emulsifying systems (SES) are crucial for drug delivery and formulation.
- Understanding the mechanism of self-emulsification, particularly the role of intermediate phases, is key to optimizing formulation performance.
- Liquid crystalline (LC) phases can form during self-emulsification and influence droplet formation.
Purpose of the Study:
- To investigate the mechanism of self-emulsification by analyzing the rheological properties of the intermediate liquid crystalline (LC) phase.
- To correlate the viscoelastic behavior of the LC phase with the droplet size and emulsification efficiency of the system.
Main Methods:
- A binary system of Tween 80 (T80) and Imwitor 742 (I742) was used to prepare SES with varying I742 concentrations (10-90%).
- Self-emulsification was monitored via visual observation and droplet size analysis.
- Polarizing microscopy, differential scanning calorimetry, and rheological studies were performed on mesophases obtained from 50% v/v hydration of SES.
Main Results:
- SES with 30% I742 produced nano-sized droplets, while other concentrations yielded micron-sized droplets.
- All SES formed intermediate LC phases, with a lamellar phase observed in 30% SES and micellar cubic phases in others.
- Rheological analysis revealed a weak, fragile mesophase structure in 30% SES, facilitating easy deformation and nano-droplet release during emulsification, contrasting with the more structured phases in other SES.
Conclusions:
- The viscoelastic properties of the intermediate liquid crystalline phase critically influence self-emulsification performance.
- A weak and fragile LC phase promotes the formation of nanoemulsions.
- This study highlights the importance of characterizing intermediate phases for optimizing self-emulsifying drug delivery systems.
