You can freely build on Using Specific Steroid Molecules to Block Salt Retention in the Body
This patent expired in 1996. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Individual
Patent granted
1978
Expired
1996
Forward citations
5
What this patent covers
This patent details a method for treating patients who retain too much salt by administering specific chemical compounds known as 11-beta,18-oxidopregnanes. These molecules act as aldosterone antagonists, meaning they compete with or block the natural hormone aldosterone, which normally signals the kidneys to hold onto sodium. By inhibiting this hormone, the drug forces the kidneys to excrete more sodium, which can help lower blood pressure or reduce fluid buildup. The claims specify a range of chemical structures, including 18-deoxyaldosterone, that can be used to achieve this effect.
What is now free to use
All 0 claims of US 4081538 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover the use of spironolactone or other non-oxidopregnane class diuretics.
Does not cover treatments for conditions unrelated to mineralocorticoid-induced sodium retention.
Does not claim the synthesis process for creating these specific chemical compounds.
Who is building on this today
Pharmaceutical companies like Pfizer and Novartis have continued to develop and refine the class of mineralocorticoid receptor antagonists, building on the fundamental understanding of how these receptors regulate sodium excretion.
Products built on expired version of this technology
Experimental diuretic therapies
Research into mineralocorticoid receptor antagonists
How to cite this patent in your documentation
Individual. US Patent 4081538. Aldosterone antagonists. Granted 1978, expired 1996. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.