pH-Triggered Release Particle for Acid-Stable Formulations
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Solution Overview
Problem
Current controlled release systems for pharmaceutical and fragrance actives in acidic formulations face challenges such as premature release, use of toxic solvents, non-GRAS materials, and costly manufacturing processes, particularly in acidic environments like the stomach or household cleaning products.
Innovation Solution
Development of controlled release particles comprising a core with a hydrophobic active material and an emulsifier, surrounded by an acid-insoluble polymer, colloidal silica, a water-insoluble divalent salt, and a film-forming polymer, designed to retain the active in acidic conditions and release it in basic environments, using GRAS materials and a cost-effective spray drying process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acrylate copolymers are used for pH triggered release, then release functionality is achieved, but toxic solvents and non-GRAS materials are required
Solution Approach 1:
The patent changes the chemical composition parameters by replacing synthetic acrylate copolymers with natural polymers (starch, cellulose, chitosan) and modifies the wall structure to achieve pH-responsive release without toxic solvents. The wall composition is adjusted to be insoluble at acidic pH but soluble or permeable at neutral/basic pH, achieving the same release functionality through parameter changes in material composition.
Solution Approach 2:
The patent employs inexpensive, biodegradable natural polymers that can be discarded after use, replacing expensive and persistent synthetic polymers. These natural polymer walls provide the necessary pH-triggered release functionality and then degrade harmlessly, eliminating the need for toxic solvent removal and allowing safe disposal.
2Reliability
If complex coating processes are used to achieve controlled release, then release control is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent combines multiple functions into a single wall structure made of natural polymers. The wall simultaneously provides structural integrity, pH-responsive release control, and biodegradability in one integrated component, eliminating the need for separate coating steps and multiple material applications that characterize complex manufacturing processes.
Solution Approach 2:
The patent segments the wall into functional zones with different natural polymer compositions - some regions provide structural stability while others provide pH-sensitivity. This segmentation allows each zone to perform its specific function efficiently, achieving controlled release without requiring complex multi-step coating processes.
3Productivity
If particles are made smaller to improve delivery, then delivery efficiency increases, but fluid bed drying becomes ineffective
Solution Approach 1:
The patent replaces the mechanical fluid bed drying system with a spray drying process. Spray drying uses atomization and rapid evaporation in a controlled chamber, allowing effective drying of sub-100 micron particles that would be carried away by air streams in fluid bed systems. This substitution of drying mechanics enables production of smaller, more efficient delivery particles.
Solution Approach 2:
The patent transitions from conventional size ranges to a different size dimension (sub-100 micron), which improves delivery efficiency by enhancing dispersion and absorption. This dimensional change is made possible by using spray drying technology that can effectively process and dry particles in this size range, overcoming the limitations of fluid bed drying.
4Object-affected harmful factors
If GRAS materials are used for safety, then safety is improved, but particle stability in acidic conditions deteriorates
Solution Approach 1:
The patent creates composite wall structures using combinations of natural polymers (starch, cellulose, chitosan) with specific chemical and physical properties. These composite materials provide both the desired safety profile of GRAS substances and the necessary stability in acidic conditions through synergistic interactions between the different polymer components.
Solution Approach 2:
The patent applies different natural polymer compositions to different regions or aspects of the wall structure. Some polymers provide acid stability while others provide biodegradability or pH-sensitivity, allowing each material to perform its optimal function in the appropriate location within the composite wall structure.
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 solution effectively stabilizes actives in acidic formulations, maintaining chemical stability during manufacturing, transport, and storage, and ensures pH-triggered release in basic conditions, avoiding premature release and toxic solvent use, while being cost-effective and suitable for various applications.
Implementation Method 1
spray drying the spray-ready emulsion to provide a powder comprising the controlled release particles
Implementation Method 2
configured to retain the at least one hydrophobic active material when exposed to an acidic aqueous solution with a pH less than 6, and to release the at least one hydrophobic active material when exposed to a basic aqueous solution with a pH greater than 7
Data Source
AI summary
Disclosed are controlled release particles, each controlled release particle of which includes: (a) a core including at least one hydrophobic active material and an emulsifier which is an oil-soluble or oil-dispersible lecithin emulsifier; and (b) a wall at least partially surrounding the core and including an acid insoluble polymer, a colloidal silica, a water insoluble divalent salt, a film forming polymer, and optionally a powder flow aid, wherein the controlled release particle is configured to retain the at least one hydrophobic active material when exposed to an acidic aqueous solution with a pH less than 6, and to release the at least one hydrophobic active material when exposed to a basic aqueous solution with a pH greater than 7. A method for preparing the particles and compositions containing the particles are also disclosed.