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.
Original patent title: “Pharmaceutical preparations containing cyclodextrin derivatives”
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. Granted to US Department of Health and Human Services in 1988 with 31 claims and 341 forward citations.
Key facts
Coverage
What does this patent actually cover?
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 (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 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).
The gap
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).
- 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.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The noveltynoveltyThe requirement that an invention be different from anything publicly known before its priority date.Read more → 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.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Testosterone formulations
Estrogen and progesterone therapies
Antiviral drug formulations (e.g., acyclovir)
Anti-inflammatory drug formulations
Oral drug delivery systems for poorly soluble compounds
Buccal administration of hormones
Why it matters
The bigger picture
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.
Filed
May 29, 1985
Granted
February 23, 1988
Market context
Who's building on this
Companies in this space
Pharmaceutical companies and drug delivery technology firms widely use cyclodextrin derivatives to improve drug solubility and bioavailability. Companies like CycloLab, Roquette, and various generic drug manufacturers develop and utilize cyclodextrin-based formulations. The original assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, the US Department of Health and Human Services, through its research arms like NIH, continues to fund and conduct research in drug delivery.
Market impact
This patent contributed to the broader understanding and application of cyclodextrins in drug formulation. It helped enable the development of more effective oral and other drug delivery systems for a wide range of poorly soluble active pharmaceutical ingredients. The use of amorphous cyclodextrin complexes became a significant strategy for improving drug bioavailability, impacting the development of new and reformulated medicines across the pharmaceutical industry.
Claim 1 — Plain English
What this patent covers
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).
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.
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.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
Strong
Citation count
40/40
Highly cited
Claim breadth
20/20
Very broad protection
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$216K – $691K
Midpoint $432K · expired or expiring · industry ×3.0
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
31 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Pitha, J. (1988). How Special Sugars Make Medicines Dissolve Better (U.S. Patent No. 4,727,064). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/4727064/azt-zidovudine
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
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).
Same assignee
More from US Department of Health and Human Services
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