High Solids Tablet Coating Composition Viscosity Control

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Solution Overview

Problem

Current coating compositions for pharmaceutical and related industries face challenges in achieving low toxicity, easy preparation, high solids content, smoothness, color stability, and uniformity, while maintaining effective drug release and processability, which existing solutions fail to adequately address.

Innovation Solution

A water-based coating composition comprising poly(N-vinyl-2-pyrrolidone-co-vinyl acetate) copolymer, a water-soluble cellulose ether, and a D-glucose film-forming agent, optionally with plasticizers and colorants, providing improved adhesion, smoothness, color stability, and processability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high solids content is used in coating composition, then productivity and coating efficiency are improved, but viscosity increases causing pumping and atomization difficulties

Engineering Contradiction:
Improvecoating efficiencyVSAvoidprocessability
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the coating system by incorporating specific polymers (acrylic copolymers, cellulose derivatives) and solvents (glycols, alcohols) to achieve high solids content (40-80% w/w) while controlling viscosity through molecular weight selection and compositional ratios

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite coating formulations combining multiple polymer types (acrylic copolymers with cellulose ethers or esters), plasticizers, and co-solvents to achieve synergistic effects that provide both high solids content and acceptable rheological properties for processing

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If coating composition is optimized for smoothness and adhesion, then product quality is improved, but formulation complexity increases

Engineering Contradiction:
Improvesurface smoothnessVSAvoidformulation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent optimizes specific formulation parameters including polymer molecular weight (10,000-1,000,000), plasticizer content (5-50% w/w), and solvent type to achieve smooth, adherent coatings without excessive formulation complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs commercially available, off-the-shelf materials (standard acrylic copolymers, common cellulose derivatives like HPMC and HPC, readily available plasticizers such as triethyl citrate and polyethylene glycol) that provide excellent performance without requiring complex or proprietary formulations

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If drying temperature is increased to reduce process time, then productivity is improved, but coating quality and substrate integrity may deteriorate

Engineering Contradiction:
Improvedrying speedVSAvoidcoating stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies the solvent system composition (using glycols, alcohols, and water in specific ratios) and polymer selection to enable controlled evaporation rates that allow higher drying temperatures without compromising coating quality or substrate integrity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses commercially available materials with inherent properties that facilitate rapid drying, such as volatile co-solvents (isopropanol, ethyl acetate) and polymers with appropriate glass transition temperatures, eliminating the need for extended drying cycles

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 described coating composition achieves superior adhesion, smoothness, color stability, and processability, enabling high-throughput production of uniformly coated products with enhanced quality and stability, overcoming limitations of prior art coatings.

Implementation Method 1

The coating liquid must possess sufficiently low viscosity to enable trouble-free pumping and atomization by the coating nozzles... An ideal coating liquid atomizes cleanly and remains sufficiently fluid after contacting the substrate (i.e., tablets) in order to spread, provide even distribution, and coalesce into a unified film.

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

an ideal coating provides sufficient robustness to enable its extensive use on a variety of substrates. Additionally, the coated product does not exhibit moisture migration between the core and coating layer(s), which can alter product stability and release profiles.

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2328539B1Smooth, high solids tablet coating composition
Publication Date: 2018.04.18 ISP INVESTMENTS LLC
  • EP2328539B1 patent drawingFigure 1
  • EP2328539B1 patent drawingFigure 2A
  • EP2328539B1 patent drawingFigure 2B

AI summary

The invention describes a coating composition comprising an effective amount of a water- soluble cellulose ether, a poly(N- vinyl pyrrolidone-co-vinyl acetate) copolymer, a film- forming agent based on D-glucose, and a plasticizer.