Last Updated: May 11, 2026

Details for Patent: 4,925,860

Name: Drug Patent Intelligence for US Patent 4925860
Creator: DrugPatentWatch
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Summary for Patent: 4,925,860

Title:	Stable pharmaceutical composition of 3-(hydroxymethyl)-5,5-diphenylhydantoin disodium phosphate ester
Abstract:	Described is a stable pharmaceutical composition of 3-(hydroxymethyl-5,5-diphenylhydantoin disodium phosphate ester, the prodrug of 5,5-diphenylhydantoin (phenytoin) a commonly used drug for the treatment and management of epilepsy and other types of convulsive states. It has been found that degradation of the prodrug to phenytoin can be controlled by controlling the pH of the composition. Controlling the pH to between 8.3 to 9.4 results in the production of diphenylglycinamide as the primary degradant and minimization of degradation to phenytoin. If the pH is maintained at a lower or higher value, then the degradation pattern changes, with earlier than expected product failure.
Inventor(s):	Dale E. Herbranson, Earl R. Speicher, Leonard S. Rosenberg
Assignee:	Bristol Myers Squibb Pharma Co
Application Number:	US07/356,948
Patent Claim Types: see list of patent claims	Use; Composition; Formulation;

Drugs Protected by US Patent 4,925,860

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

International Family Members for US Patent 4,925,860

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Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0473687	⤷ Start Trial	SPC/GB98/030	United Kingdom	⤷ Start Trial
European Patent Office	0473687	⤷ Start Trial	99C0008	Belgium	⤷ Start Trial
European Patent Office	0473687	⤷ Start Trial	C980045	Netherlands	⤷ Start Trial
European Patent Office	0473687	⤷ Start Trial	3/1999	Austria	⤷ Start Trial
Austria	135907	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

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