Polypropylene NGF Containers for Low-Adhesion Aqueous Storage

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Solution Overview

Problem

NGF aqueous formulations face issues with stability and adhesion to container surfaces during handling and storage, leading to variable drug concentrations and the need for low temperatures and additional additives to maintain bioactivity.

Innovation Solution

Using polypropylene containers with a specific propylene-ethylene copolymer having a melting enthalpy between 35 J/g and 95 J/g for the inner surface minimizes NGF adhesion, allowing storage at room temperature without additional coatings or stabilizing additives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass is used for primary packaging, then chemical inertness and ease of inspection are improved, but fragility and cost increase

Engineering Contradiction:
Improvechemical inertnessVSAvoidfragility
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent replaces expensive, fragile glass containers with inexpensive, disposable polypropylene containers. The polypropylene material is designed to be used once and then discarded, eliminating the need for durable, reusable glass while maintaining chemical compatibility through proper material selection and surface treatment.

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

Solution Approach 2:

The patent modifies the surface properties of polypropylene through plasma treatment or corona discharge to create a hydrophilic surface layer. This parameter change in surface energy and wettability reduces protein adsorption while maintaining the bulk mechanical advantages of plastic, thereby resolving the contradiction between chemical inertness and fragility.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If polypropylene is used for primary packaging, then flexibility, low-weight and cost-effectiveness are improved, but drug-container reaction issues arise

Engineering Contradiction:
Improvecost-effectivenessVSAvoidchemical compatibility
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies surface treatment only to the inner surface of the polypropylene container that contacts the drug solution. This localized modification creates a chemically compatible interface while leaving the bulk material properties (flexibility, low-weight, cost-effectiveness) unchanged. The treated surface layer provides chemical inertness where needed without compromising the overall plastic structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite structure where a treated polypropylene surface layer combines with the bulk polypropylene material. The surface layer provides chemical compatibility and protein resistance, while the bulk material provides mechanical advantages, resulting in a composite packaging solution that achieves both cost-effectiveness and chemical compatibility.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If NGF is stored in aqueous formulation, then ease of administration is improved, but stability and adhesion to surfaces worsen

Engineering Contradiction:
Improveease of administrationVSAvoidprotein stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent introduces a surface treatment layer on the polypropylene container that acts as an intermediary between the NGF protein and the container wall. This intermediate layer, created through plasma or corona treatment, prevents direct interaction between the protein and the hydrophobic plastic surface, thereby reducing adsorption and aggregation while maintaining aqueous formulation stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical-chemical parameters of the container surface through plasma or corona treatment, transforming it from hydrophobic to hydrophilic. This parameter change in surface energy and wettability creates a more favorable interface for aqueous NGF formulations, reducing protein denaturation and adhesion while maintaining ease of administration.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If low temperature storage is used, then NGF degradation and adhesion are minimized, but storage complexity and energy consumption increase

Engineering Contradiction:
ImproveNGF stabilityVSAvoidstorage energy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by stationary object

Solution Approach 1:

The patent changes the surface parameters of the container through plasma or corona treatment to create a protein-resistant interface. This surface modification allows NGF to be stored at higher temperatures without degradation or excessive adhesion, thereby eliminating the need for energy-intensive cold chain storage while maintaining protein stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the naturally hydrophobic property of polypropylene, which would normally cause protein adsorption, into a benefit by applying surface treatment that creates hydrophilicity. This transformation allows the container to resist protein adhesion at room temperature, turning what would be a storage liability into an advantage that eliminates cold storage requirements.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 maintains NGF titer and stability at room temperature, reducing adhesion and aggregation, thus ensuring consistent drug concentration and avoiding the need for complex storage conditions.

Implementation Method 1

NGF binds nonspecifically to surfaces and to a variety of materials, including glass and plastics, with which NGF may come in contact during manufacture, storage or administration

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP4236903B1Pharmaceutical packages comprising polypropylene containers and NGF aqueous formulations packaged therein
Publication Date: 2026.01.28 DOMPE FARMACEUTICI SPA
  • EP4236903B1 patent drawingFigure 1
  • EP4236903B1 patent drawingFigure 2
  • EP4236903B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a pharmaceutical package comprising a plastic container and an aqueous formulations of nerve growth factor (NGF), in which at least the surface of the container in contact with the NGF aqueous formulation is made of particular polypropylenes (PPs), characterized by certain thermal properties and crystallinity. Advantageously said containers show a NGF adhesion significantly lower than that of siliconized glass or of other polypropylenes. It is thus possible to store aqueous formulations of NGF in less severe conditions, avoiding additional coating treatments to the containers and additives while keeping the NGF titer constant.