Structured Surfactant Suspension for Pharmaceutical Stability
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Solution Overview
Problem
Current pharmaceutical suspensions face challenges such as sedimentation, high viscosity, and instability, limiting their use for internal administration due to insolubility issues and the inability to suspend coarse particles effectively, while existing structured surfactant systems are not suitable for pharmaceutical and food applications due to high surfactant levels, taste, and temperature instability.
Innovation Solution
A mixture of a sugar ester or triterpenoid glycoside with a high HLB and a minor proportion of a fatty acid forms a robust, low viscosity, self-structuring system capable of suspending pharmaceutical active ingredients at reduced surfactant levels, which is tasteless and stable at high temperatures, using a composition comprising water, sugar, and surfactant with a surfactant component comprising a major portion of sugar ester or triterpenoid glycoside and a minor portion of fatty acid or lecithin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thickeners (gums or polymers) are used to raise viscosity, then sedimentation is retarded, but the suspension is not stable and becomes unacceptably viscous
Solution Approach 1:
The patent changes the fundamental parameter of the suspending medium from a simple aqueous solution to a structured surfactant system with specific rheological properties. The surfactant concentration and HLB value are optimized to achieve the right balance between suspension stability and pourability, eliminating the need for excessive thickening agents.
Solution Approach 2:
The invention uses a composite surfactant system combining multiple surfactants with different HLB values (e.g., high HLB surfactant like sugar ester and low HLB surfactant) to create a structured system that provides both suspension stability and acceptable flow properties, avoiding the drawbacks of single-component thickeners.
2Stability of the object's composition
If colloidal dispersions are used to prevent sedimentation, then particles remain suspended, but coarse particles cannot be dispersed and Ostwald ripening occurs
Solution Approach 1:
The patent changes the particle size parameter that can be suspended by transitioning from colloidal systems (sub-micron) to structured surfactant systems that can immobilize larger non-colloidal particles through their rheological properties and yield point, preventing sedimentation across a broader particle size range.
3Quantity of substance
If high concentrations of solids are suspended, then therapeutic dosing range is achieved, but the product becomes unacceptably viscous
Solution Approach 1:
The invention changes the rheological parameters of the continuous phase by using structured surfactant systems with specific yield points and flow characteristics, enabling higher solid concentrations to be suspended without reaching unacceptably high viscosities, thus allowing adequate therapeutic dosing ranges.
4Stability of the object's composition
If existing structured surfactant systems are used, then suspension stability is achieved, but high surfactant levels cause taste issues and temperature instability
Solution Approach 1:
The patent optimizes the HLB parameter of the surfactant system and adjusts surfactant concentration to achieve stable suspensions at lower levels, reducing taste issues. The surfactant selection and concentration are also optimized for temperature stability, preventing phase separation and maintaining suspension integrity across a wider temperature range.
Solution Approach 2:
The invention uses composite surfactant systems combining surfactants with complementary properties (different HLB values, temperature stability characteristics) to achieve both suspension stability and improved taste/temperature performance, leveraging the synergistic effects of multiple surfactant components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves stable suspension of non-colloidal particles for prolonged periods with minimal sedimentation, low viscosity, and improved flavor, allowing for effective pharmaceutical and veterinary use without the need for high surfactant concentrations or bent chain surfactants, thus overcoming the limitations of existing technologies.
Implementation Method 1
structured suspending systems depend on the rheological properties of the suspending medium to immobilise the particles, irrespective of size
Implementation Method 2
This requires the suspending medium to exhibit a yield point, which is higher than the sedimenting or creaming force exerted by the suspended particles
Implementation Method 3
The latter contain particles of about 1 micron or smaller, which are prevented from sedimenting by Brownian motion
Implementation Method 4
a mixture of a sugar ester or triterpenoid glycoside with a high HLB and a minor proportion of a fatty acid forms a robust, low viscosity system with suspending properties... which is tasteless and self-structuring in water
Implementation Method 5
The structure reforms sufficiently rapidly to prevent sedimentation, once the agitation caused by the external stress has ceased
Data Source
AI summary
The present invention provides structured surfactant systems comprising water and from 0 to saturation of sugar, together with sufficient surfactant to form a structure capable of suspending solids, wherein the surfactant comprises a mixture of: (i) a major portion of at least one sugar ester and/or a triterpenoid glycoside (saponin) having an HLB greater than 10; and (ii) a minor portion of at least one fatty acid and/or lecithin. The invention further provides pharmaceutical compositions comprising a structured surfactant system of the invention and a pharmaceutical or veterinary active ingredient.