# Using Vitamin B12 to Help Proteins Survive the Human Digestive System > A method for attaching therapeutic proteins to Vitamin B12 so they can be absorbed through the gut instead of being injected. - **Patent:** US 5574018 - **Original title:** Conjugates of vitamin B12 and proteins - **Owner:** Amgen Inc - **Granted:** 1996 - **Status:** Public domain (expired) - **Times cited:** 46 - **Field:** biotech, pharmaceutical ## What it does This patent describes a chemical trick to help large, fragile therapeutic proteins survive the harsh environment of the human stomach and intestines. By covalently linking a protein—like erythropoietin or interferon—to the primary hydroxyl site of a Vitamin B12 molecule, the drug hitches a ride on the body's natural B12 absorption pathway. The patent claims specific chemical formulas for these conjugates and a method for synthesizing them using dicarboxylic acid derivatives. When taken orally, the B12 acts as a transport vehicle, potentially allowing patients to take pills instead of receiving painful injections. ## What it does NOT cover - Does not cover the use of Vitamin B12 as a standalone nutritional supplement. - Does not cover non-covalent mixtures or simple physical blends of protein and B12. - Does not cover conjugation methods that attach to parts of the B12 molecule other than the primary 5'-hydroxyl group on the ribose moiety. - Does not cover protein delivery systems that rely on liposomes or nanoparticle encapsulation. ## The clever bit The innovation lies in hijacking the body's highly specific, evolutionarily conserved transport mechanism for Vitamin B12 to smuggle large, complex therapeutic proteins across the intestinal wall. ## Real-world examples 1. Oral delivery systems for recombinant proteins like erythropoietin (EPO). 2. Oral formulations of granulocyte colony-stimulating factor (G-CSF). 3. Experimental oral interferon therapies. ## Why it matters Many life-saving drugs, particularly those made by recombinant DNA technology, are proteins that the stomach acid would destroy before they could reach the bloodstream. This patent represents an early attempt to solve the 'oral delivery' problem for biologics, which remains a massive hurdle in pharmaceutical engineering. If successful, such technology could replace daily injections for patients with chronic conditions like anemia or immune deficiencies. ## Frequently asked questions ### What does Using Vitamin B12 to Help Proteins Survive the Human Digestive System cover? A method for attaching therapeutic proteins to Vitamin B12 so they can be absorbed through the gut instead of being injected. ### Who owns patent US 5574018? Amgen Inc owns this patent, granted in 1996. ### 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 5574018 cited by? This patent has been cited by 46 later patents that build on its ideas. ### What problem does this patent solve? Many life-saving drugs, particularly those made by recombinant DNA technology, are proteins that the stomach acid would destroy before they could reach the bloodstream. This patent represents an early attempt to solve the 'oral delivery' problem for biologics, which remains a massive hurdle in pharmaceutical engineering. If successful, such technology could replace daily injections for patients with chronic conditions like anemia or immune deficiencies. ### What does this patent NOT cover? Does not cover the use of Vitamin B12 as a standalone nutritional supplement. **Full plain-English explainer:** https://patentbrief.org/patent/us/5574018/herceptin-trastuzumab **Original patent:** https://patents.google.com/patent/US5574018 --- _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 Drug Proteins Last Longer and Target Diseases Better](https://patentbrief.org/patent/us/20190160160/methods-to-treat-diseases-with-protein-peptide-and-antigen-modification) — This patent describes ways to make protein and peptide drugs stay in the body longer and target specific diseases like autoimmune conditions or cancer more precisely by linking them together or combining them with other molecules. - [How Special Sugars Make Medicines Dissolve Better](https://patentbrief.org/patent/us/4727064/azt-zidovudine) — This patent describes how to make poorly water-soluble drugs dissolve and absorb better by mixing them with specially modified, non-crystalline sugar molecules called cyclodextrin derivatives. - [Using Yeast Cell Walls to Deliver Genetic Medicine](https://patentbrief.org/patent/us/8580275/car-t-cell-therapy) — A method for using hollowed-out yeast cell walls as tiny transport containers to deliver genetic payloads like DNA or RNA into cells. - [How to Build Smaller, Synthetic Antibody-Like Molecules for Medicine](https://patentbrief.org/patent/us/5455030/immunotheraphy-using-single-chain-polypeptide-binding-molecules) — This patent describes a way to create small, single-chain proteins that mimic the binding power of full-sized antibodies to deliver medicine more effectively. - [How to Make Human Erythropoietin (EPO) Using Engineered DNA](https://patentbrief.org/patent/us/4703008/neupogen-g-csf-filgrastim) — This patent describes the specific DNA sequences and methods to engineer cells to produce erythropoietin (EPO), a protein vital for red blood cell production, outside the human body.