# How Special Sugars Make Medicines Dissolve Better

> 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.

- **Patent:** US 4727064
- **Original title:** Pharmaceutical preparations containing cyclodextrin derivatives
- **Owner:** US Department of Health and Human Services
- **Granted:** 1988
- **Status:** Public domain (expired)
- **Times cited:** 341
- **Field:** pharmaceutical, biotech, materials, chemistry

## What it does

The patent describes a way to create a stable drug mixture that helps medicines dissolve in the body. It starts with a special type of sugar molecule, called a cyclodextrin derivative, which has been chemically changed to be water-soluble and non-crystalline (amorphous). These modified cyclodextrins are dissolved in water (Claim 1, step 1). Then, a drug that doesn't dissolve well in water, like a hormone such as testosterone (Claim 5), is added to this solution. The cyclodextrins wrap around the drug molecules, forming a "solubilized drug/cyclodextrin complex" (Claim 1, step 2) that dissolves much better. This improved dissolution helps the body absorb the medicine more effectively. The resulting complex can be dried into a powder (Claim 2) or used in liquid form (Claim 11).

## What it does NOT cover

- Does not cover using cyclodextrins that are not chemically modified derivatives (e.g., plain alpha, beta, or gamma cyclodextrins).
- Does not cover drug-cyclodextrin complexes that are crystalline rather than amorphous.
- Does not cover drugs that are already highly water-soluble.
- Does not cover methods where the cyclodextrin mixture is not intrinsically amorphous before complexing with the drug.
- Does not cover cyclodextrin derivatives made using alkylation agents other than those exemplified (e.g., propylene oxide, glycidol, iodoacetamide, chloroacetate, 2-diethylaminoethylchloride) or similar non-selective alkylation processes.

## The clever bit

The novelty lies in using an amorphous mixture of cyclodextrin derivatives. By ensuring the cyclodextrins themselves are non-crystalline and a mixture of many components, they prevent the drug-cyclodextrin complex from crystallizing. This stable, non-crystalline state is key to improving the drug's dissolution and absorption.

## Real-world examples

1. Testosterone formulations
2. Estrogen and progesterone therapies
3. Antiviral drug formulations (e.g., acyclovir)
4. Anti-inflammatory drug formulations
5. Oral drug delivery systems for poorly soluble compounds
6. Buccal administration of hormones

## Why it matters

Many effective drugs don't dissolve well in water, making it hard for the body to absorb them. This patent offers a method to overcome this challenge, potentially making such drugs more effective or allowing for lower doses. This technology is fundamental to improving the "bioavailability" of medicines, ensuring that a larger portion of the drug reaches its target in the body. It has implications for a wide range of pharmaceutical products, from hormones to antiviral agents.

## Frequently asked questions

### What does How Special Sugars Make Medicines Dissolve Better cover?

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.

### Who owns patent US 4727064?

US Department of Health and Human Services owns this patent, granted in 1988.

### 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 4727064 cited by?

This patent has been cited by 341 later patents that build on its ideas.

### What problem does this patent solve?

Many effective drugs don't dissolve well in water, making it hard for the body to absorb them. This patent offers a method to overcome this challenge, potentially making such drugs more effective or allowing for lower doses. This technology is fundamental to improving the "bioavailability" of medicines, ensuring that a larger portion of the drug reaches its target in the body. It has implications for a wide range of pharmaceutical products, from hormones to antiviral agents.

### What does this patent NOT cover?

Does not cover using cyclodextrins that are not chemically modified derivatives (e.g., plain alpha, beta, or gamma cyclodextrins).

**Full plain-English explainer:** https://patentbrief.org/patent/us/4727064/azt-zidovudine

**Original patent:** https://patents.google.com/patent/US4727064

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