# Preventing Protein Damage with Extra Methionine > This 1993 patent describes how adding extra methionine to protein-based medicines can prevent them from degrading, especially in liquid or semi-solid forms. - **Patent:** US 5272135 - **Original title:** Method for the stabilization of methionine-containing polypeptides - **Owner:** Chiron Ophthalmics Inc - **Granted:** 1993 - **Status:** Public domain (expired) - **Times cited:** 63 - **Field:** pharmaceutical, biotech, materials ## What it does This patent details a method to stop proteins, specifically those with a methionine amino acid, from oxidizing and breaking down when stored in liquid or semi-solid medicines. The key is to add extra methionine, an amino acid that is part of the protein, to the preparation. This added methionine acts as a shield, getting oxidized itself instead of the methionine within the therapeutic protein. The patent specifies adding methionine in amounts between 0.01% and 0.3% by weight or volume, ensuring that the therapeutic protein remains stable for storage and use. For example, claim 8 describes using this method with epidermal growth factor in a liquid solution. ## What it does NOT cover - Methods that do not involve adding methionine to inhibit oxidation. - Methods for stabilizing proteins that do not contain any methionine residues. - Stabilization of proteins in solid dosage forms (e.g., pills, powders). - Adding methionine in concentrations outside the specified range of 0.01% to 0.3%. - Inhibiting oxidation of molecules other than polypeptides. ## The clever bit The inventors realized that methionine, an amino acid naturally present in many proteins, is particularly susceptible to oxidation. By adding extra methionine to the formulation, they created a sacrificial agent that preferentially oxidizes, thereby protecting the methionine residues within the therapeutic protein itself. ## Real-world examples 1. Ophthalmic solutions containing growth factors 2. Creams or ointments with therapeutic proteins 3. Liquid formulations of recombinant proteins ## Why it matters This patent addresses a critical challenge in biopharmaceutical development: maintaining the stability and efficacy of protein-based drugs. Proteins are delicate molecules prone to degradation, which can render them useless or even harmful. By providing a simple yet effective method to prevent oxidation, this patent likely contributed to the viability of developing and commercializing various protein therapeutics, particularly those intended for topical or injectable use. ## Frequently asked questions ### What does Preventing Protein Damage with Extra Methionine cover? This 1993 patent describes how adding extra methionine to protein-based medicines can prevent them from degrading, especially in liquid or semi-solid forms. ### Who owns patent US 5272135? Chiron Ophthalmics Inc owns this patent, granted in 1993. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 5272135 cited by? This patent has been cited by 63 later patents that build on its ideas. ### What problem does this patent solve? This patent addresses a critical challenge in biopharmaceutical development: maintaining the stability and efficacy of protein-based drugs. Proteins are delicate molecules prone to degradation, which can render them useless or even harmful. By providing a simple yet effective method to prevent oxidation, this patent likely contributed to the viability of developing and commercializing various protein therapeutics, particularly those intended for topical or injectable use. ### What does this patent NOT cover? Methods that do not involve adding methionine to inhibit oxidation. **Full plain-English explainer:** https://patentbrief.org/patent/us/5272135/lipitor-atorvastatin **Original patent:** https://patents.google.com/patent/US5272135 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [Making High-Concentration Antibody Medicines Stable for Injection](https://patentbrief.org/patent/us/6267958/rituxan-chop) — Genentech's 2001 patent on a method to create stable, concentrated antibody medicines that can be easily reconstituted for injection, preventing degradation during freezing and storage. - [How Specific Antibody Drugs Are Stabilized for Storage and Use](https://patentbrief.org/patent/us/8372396/tysabri-natalizumab) — Genentech's 2013 patent details a precise recipe for an antibody drug, like Pertuzumab, using a special buffer, sugar, and cleaning agent to keep it stable for patients. - [How to Keep High-Concentration Antibody Medicines Stable in Liquid Form](https://patentbrief.org/patent/us/7740842/herceptin-adjuvant-therapy) — Novartis's patent describes a specific liquid recipe for keeping high concentrations of E25 anti-IgE antibodies stable and usable for medical injections. - [Improving How Blood Platelets Are Stored](https://patentbrief.org/patent/us/12733635/platelet-storage-methods-and-compositions) — This patent describes new chemical compounds and methods to prevent damage to blood platelets when they are stored, like in blood banks, making them last longer and more effective for transfusions. - [How to Make Anthrax Vaccines That Survive Freezing](https://patentbrief.org/patent/us/10357559/luxturna-voretigene-neparvovec) — A method for protecting sensitive anthrax vaccines from damage during freezing and thawing by using specific sugars and additives during the drying process.