Coating Composition Stabilizing Natural Dyes with Cyclodextrins
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Solution Overview
Problem
Existing coating compositions for ingestible solid forms, such as pharmaceutical and dietary supplement tablets, face challenges in achieving stable, intense color under prolonged light exposure without using azo dyes, as natural dyes derived from fruit and vegetables often lack light stability.
Innovation Solution
A coating composition comprising a film-forming polymer, auxiliary coating agents, and coloring foodstuffs from concentrated fruits and vegetables, which are processed to retain their organoleptic characteristics and provide a stable, intense color when used in conjunction with film-forming agents like methyl cellulose and hydroxypropylmethyl cellulose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If natural dyes are used to color coating compositions, then bright colors can be obtained, but light stability is mediocre
Solution Approach 1:
The patent changes the chemical parameters of natural dyes by combining them with cyclodextrins, which form inclusion complexes that protect the dye molecules from photodegradation while maintaining their color properties. This parameter change transforms the light-stability characteristic of natural dyes without sacrificing their brightness.
Solution Approach 2:
The patent creates a composite coating composition that combines natural dyes with cyclodextrins (specifically beta-cyclodextrin and its derivatives). This composite material leverages the color-providing ability of natural dyes and the protective encapsulation capability of cyclodextrins to achieve both bright color and improved light stability.
2Illumination intensity
If azo dyes are used to impart bright color to the film, then intense color is achieved, but regulatory changes require alternative coloring systems
Solution Approach 1:
The patent replaces long-term problematic azo dyes with natural dyes that are inherently safer and compliant with evolving regulations. While natural dyes alone have mediocre stability, the combination with cyclodextrins extends their usable life and reliability to match or exceed azo dyes, while maintaining regulatory compliance.
Solution Approach 2:
Cyclodextrins act as an intermediary substance between the natural dye molecules and the external environment (light, oxygen). This intermediary protects the dye molecules from degradation factors while allowing them to maintain their color function, effectively bridging the gap between natural safety and performance requirements.
3Ease of manufacture
If selective extraction of coloring molecules is performed, then natural dyes are obtained, but light stability remains mediocre
Solution Approach 1:
The patent applies preliminary action by incorporating cyclodextrins into the coating composition before application. These cyclodextrins pre-organize themselves to form protective complexes with natural dye molecules, establishing a protective structure in advance that prevents light-induced degradation before it can occur.
Solution Approach 2:
Cyclodextrins provide beforehand cushioning by forming protective inclusion complexes with natural dye molecules prior to exposure to light. This protective structure acts as a cushion against photodegradation, allowing the natural dyes to maintain their color properties throughout the product's shelf life and beyond.
Data Source
AI summary
A coating composition includes, in relation to 100% of the weight thereof: between 10 and 90 wt. % of at least one film-forming polymer selected from cellulosic polymers or derivatives of cellulosic polymers, derivatives of vinyl alcohol, derivatives of vinyl pyrrolidones, polymers of a natural origin, acrylic or methacrylic derivatives, derivatives of glycol or propylene glycol or combinations of the two substances or the copolymers of vinyl alcohol and polyethylene glycol (PEG); between 1 and 50 wt. % of at least one food colouring agent; and between 0 and 50 wt. % of at least one auxiliary coating agent selected from white opacifiers, diluents, surfactants, plasticizers, and anti-foaming agents.