# How to Store Fragile Biological Materials Without Refrigeration

> A method for preserving unstable biological materials like proteins by trapping them in a solid, glass-like sugar or polymer matrix that prevents decay at room temperature.

- **Patent:** US RE39497
- **Original title:** USRE39497E1 - Storage of materials
- **Owner:** Nektar Therapeutics
- **Granted:** 2007
- **Status:** Public domain (expired)
- **Times cited:** 11
- **Field:** biotech, pharmaceutical, materials

## What it does

This patent describes a way to keep delicate biological materials, such as proteins or enzymes, from breaking down when they are not kept in a fridge. It works by dissolving the fragile material into a water-soluble carrier, like a sugar or a synthetic polymer, and then turning that mixture into a solid, glassy, amorphous state. Because the material is locked inside this rigid 'glass,' it cannot move or react, effectively pausing its degradation at room temperature. When a scientist needs to use the material again, they simply add water to dissolve the glass and release the active substance.

## What it does NOT cover

- Does not cover materials that are already stable in aqueous solution at room temperature.
- Does not cover storage methods that rely on freezing or standard refrigeration.
- Does not cover the storage of rennin specifically, as it is explicitly excluded in claim 17.
- Does not cover liquid-state storage solutions that do not form a glassy amorphous solid.

## The clever bit

The innovation lies in using the glass transition state of a sugar or polymer matrix to physically immobilize molecules, preventing the molecular movement necessary for chemical degradation without needing to lower the temperature.

## Real-world examples

1. Lyophilized (freeze-dried) protein therapeutics
2. Room-temperature stable diagnostic test reagents
3. Stabilized enzyme formulations for industrial use

## Why it matters

This technology is vital for the pharmaceutical and biotech industries, where shipping temperature-sensitive medicines like vaccines or therapeutic proteins is expensive and logistically difficult. By removing the need for a 'cold chain'—the continuous refrigeration of products from factory to patient—this method reduces costs and increases access to life-saving drugs in regions lacking reliable electricity.

## Frequently asked questions

### What does How to Store Fragile Biological Materials Without Refrigeration cover?

A method for preserving unstable biological materials like proteins by trapping them in a solid, glass-like sugar or polymer matrix that prevents decay at room temperature.

### Who owns patent US RE39497?

Nektar Therapeutics owns this patent, granted in 2007.

### When does this patent expire?

This patent is expected to expire on February 27, 2027, when the invention enters the public domain.

### What is patent US RE39497 cited by?

This patent has been cited by 11 later patents that build on its ideas.

### What problem does this patent solve?

This technology is vital for the pharmaceutical and biotech industries, where shipping temperature-sensitive medicines like vaccines or therapeutic proteins is expensive and logistically difficult. By removing the need for a 'cold chain'—the continuous refrigeration of products from factory to patient—this method reduces costs and increases access to life-saving drugs in regions lacking reliable electricity.

### What does this patent NOT cover?

Does not cover materials that are already stable in aqueous solution at room temperature.

**Full plain-English explainer:** https://patentbrief.org/patent/us/RE39497/epogen-epoetin-alfa

**Original patent:** https://patents.google.com/patent/USRE39497

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._