# Boosting Anti-Infective Activity with Muramyldipeptides and Liposomes

> This patent describes a method to make anti-infective drugs called muramyldipeptides work better by injecting them separately but close in time with tiny fat bubbles called liposomes into an animal.

- **Patent:** US 4522811
- **Original title:** Serial injection of muramyldipeptides and liposomes enhances the anti-infective activity of muramyldipeptides
- **Owner:** Syntex USA LLC
- **Granted:** 1985
- **Status:** Public domain (expired)
- **Times cited:** 2,340
- **Field:** biotech, pharmaceutical, drug_delivery, immunology

## What it does

The patent details a method to improve how well muramyldipeptide (MDP) compounds fight infections. This involves giving an animal two separate intravenous injections: first, an unencapsulated MDP compound, and second, liposomes. The key is that these two injections must happen within three hours of each other, as stated in claim 1. This serial injection approach enhances the MDP compound's ability to combat infections. For example, if a lab animal has a bacterial infection, this method could make the MDP treatment more effective than giving the MDP alone.

## What it does NOT cover

- Does not cover injecting the muramyldipeptide (MDP) compound directly inside the liposomes; it specifies 'unencapsulated MDP compound' in claim 1.
- Does not cover administering the MDP compound and liposomes more than three hours apart, as claim 1 requires them to be 'within three hours of each other'.
- Does not cover methods of delivery other than 'serial intravenous injection' (e.g., oral administration or intramuscular shots).
- Does not cover using MDP compounds or liposomes alone; the method requires both components to be serially injected.
- Does not cover applications outside of 'an animal in need thereof', meaning it's not for cell cultures or inanimate objects.

## The clever bit

The novelty lies in the specific timing and separate delivery of the unencapsulated muramyldipeptide and liposomes. Instead of combining them, the patent found that injecting them serially, within a short window, significantly boosts the anti-infective effect, suggesting a unique synergistic mechanism.

## Real-world examples

1. Experimental immune-boosting therapies
2. Adjuvants in vaccine development
3. Research into host defense mechanisms against pathogens
4. Drug delivery systems in preclinical studies

## Why it matters

Enhancing the effectiveness of anti-infective agents is crucial for treating diseases and potentially combating drug resistance. This method aims to boost the body's immune response to fight off infections more efficiently. By making existing compounds like muramyldipeptides more potent, it could lead to better patient outcomes and potentially lower dosages of the active drug.

## Frequently asked questions

### What does Boosting Anti-Infective Activity with Muramyldipeptides and Liposomes cover?

This patent describes a method to make anti-infective drugs called muramyldipeptides work better by injecting them separately but close in time with tiny fat bubbles called liposomes into an animal.

### Who owns patent US 4522811?

Syntex USA LLC owns this patent, granted in 1985.

### 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 4522811 cited by?

This patent has been cited by 2340 later patents that build on its ideas.

### What problem does this patent solve?

Enhancing the effectiveness of anti-infective agents is crucial for treating diseases and potentially combating drug resistance. This method aims to boost the body's immune response to fight off infections more efficiently. By making existing compounds like muramyldipeptides more potent, it could lead to better patient outcomes and potentially lower dosages of the active drug.

### What does this patent NOT cover?

Does not cover injecting the muramyldipeptide (MDP) compound directly inside the liposomes; it specifies 'unencapsulated MDP compound' in claim 1.

**Full plain-English explainer:** https://patentbrief.org/patent/us/4522811/human-growth-hormone-protropin

**Original patent:** https://patents.google.com/patent/US4522811

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