US4756710A
Expired / Lapsed
US
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pH-Mediated drug delivery system
Assignee: Merck and Co Inc
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Filing: 1986-03-07
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Granted: 1988-07-12
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Expires: 2006-03-07
Abstract
Abstract A method and device for delivering acidic or basic drugs in a controlled delivery system is described.
Inventors
- 👤 Joseph V. Bondi
- 👤 Alice E. Loper
- 👤 Edward M. Cohen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:50
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/70; A61K9/7023; A61K9/703; A61K9/7084
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
75 words
A method for controlled release of a weakly acidic or basic substantially unionized drug in a transdermal delivery system which comprises providing the drug in a pH controlled reservoir, said reservoir comprising ionized and unionized forms of the drug in a buffered solution and allowing the drug to pass from the drug reservoir through a membrane selectively permeable to the unionized form of the drug and substantially impermeable to the ionized form of the drug.
Claim 2
Independent Claim
75 words
A method for controlled release of a weakly acidic or basic substantially unionized drug in a transdermal delivery system which comprises providing the drug in a pH controlled reservoir, said reservoir comprising ionized and unionized forms of the drug in a buffered solution and allowing the drug to pass from the drug reservoir through a membrane selectively permeable to the unionized form of the drug and substantially impermeable to the ionized form of the drug.
Claim 3
Independent Claim
88 words
A method of administering timolol transdermally as a free base under controlled conditions comprising providing timolol in a pH rate controlling reservoir, said reservoir comprising ionized and unionized forms of timolol, a buffering agent and a vehicle in which both forms of timolol are soluble, and allowing timolol to pass from the reservoir to the dermal surface by positive pH control through a membrane selectively permeable to but not rate controlling for the unionized free base form of timolol and impermeable to the ionized salt form of timolol.
Claim 4
Independent Claim
88 words
A method of administering timolol transdermally as a free base under controlled conditions comprising providing timolol in a pH rate controlling reservoir, said reservoir comprising ionized and unionized forms of timolol, a buffering agent and a vehicle in which both forms of timolol are soluble, and allowing timolol to pass from the reservoir to the dermal surface by positive pH control through a membrane selectively permeable to but not rate controlling for the unionized free base form of timolol and impermeable to the ionized salt form of timolol.
Claim 5
Dependent Claim
73 words
A transdermal delivery system suitable for administering a weakly acidic or basic drug which comprises (a) a substantially impermeable backing member, (b) a drug reservoir comprising the drug in both ionized and unionized forms, a hydroxylated solvent and a buffering agent, and (c) a membrane selectively permeable to but not rate controlling for the unionized form of the drug and substantially impermeable to the ionized form of the drug and the buffer salts.
Claim 6
Dependent Claim
73 words
A transdermal delivery system suitable for administering a weakly acidic or basic drug which comprises (a) a substantially impermeable backing member, (b) a drug reservoir comprising the drug in both ionized and unionized forms, a hydroxylated solvent and a buffering agent, and (c) a membrane selectively permeable to but not rate controlling for the unionized form of the drug and substantially impermeable to the ionized form of the drug and the buffer salts.
Claim 7
Dependent Claim
11 words
A system according to claim 3 wherein the drug is timolol.
Claim 8
Dependent Claim
134 words
A transdermal delivery system for delivery of acidic or basic drugs comprising (a) a backing member substantially impermeable to the drug, (b) a drug reservoir adjacent to the backing member comprising both ionized and unionized forms of the drug, and a buffering agent dispersed in a carrier, said carrier being permeable to the drug, and (c) a membrane selectively permeable to but not rate controlling for the unionized form of the drug and substantially impermeable to the ionized form; wherein the concentration of the drug in the unionized form, C, and the membrane thickness, h, is related in a manner to provide a flux, J, in accordance with the equation J=(K.D.C.)/h wherein K is the partition coefficient between the drug reservoir and the membrane and D is the drug diffusion coefficient in the membrane.
Claim 9
Dependent Claim
134 words
A transdermal delivery system for delivery of acidic or basic drugs comprising (a) a backing member substantially impermeable to the drug, (b) a drug reservoir adjacent to the backing member comprising both ionized and unionized forms of the drug, and a buffering agent dispersed in a carrier, said carrier being permeable to the drug, and (c) a membrane selectively permeable to but not rate controlling for the unionized form of the drug and substantially impermeable to the ionized form; wherein the concentration of the drug in the unionized form, C, and the membrane thickness, h, is related in a manner to provide a flux, J, in accordance with the equation J=(K.D.C.)/h wherein K is the partition coefficient between the drug reservoir and the membrane and D is the drug diffusion coefficient in the membrane.
Claim 10
Dependent Claim
112 words
A transdermal delivery system for delivery of acidic or basic drugs comprising (a) a substantially impermeable backing member, (b) a drug reservoir adjacent to the backing member comprising both ionized and unionized forms of the drug in a pH controlled buffer system of a buffering agent and a vehicle in which both forms of the drug are soluble, said system providing a rate controlling pH environment by controlling the concentration of the unionized basic or acidic form of the drug, and (c) a membrane permeable to the passage of but not rate controlling for the drug in the unionized form and substantially impermeable to passage of the drug in the ionized form.
Claim 11
Dependent Claim
112 words
A transdermal delivery system for delivery of acidic or basic drugs comprising (a) a substantially impermeable backing member, (b) a drug reservoir adjacent to the backing member comprising both ionized and unionized forms of the drug in a pH controlled buffer system of a buffering agent and a vehicle in which both forms of the drug are soluble, said system providing a rate controlling pH environment by controlling the concentration of the unionized basic or acidic form of the drug, and (c) a membrane permeable to the passage of but not rate controlling for the drug in the unionized form and substantially impermeable to passage of the drug in the ionized form.
Claim 12
Dependent Claim
55 words
An improved transdermal bandage for delivery of basic or acidic drugs comprising (a) an impermeable backing member (b) a drug reservoir comprising a drug in both ionized and unionized forms, a buffering agent and a reservoir vehicle, and (c) a membrane selectively permeable to but not rate controlling for the unionized form of the drug.
Claim 13
Dependent Claim
55 words
An improved transdermal bandage for delivery of basic or acidic drugs comprising (a) an impermeable backing member (b) a drug reservoir comprising a drug in both ionized and unionized forms, a buffering agent and a reservoir vehicle, and (c) a membrane selectively permeable to but not rate controlling for the unionized form of the drug.
Claim 14
Dependent Claim
28 words
A bandage according to claim 7 which has, in addition, an adhesive coating along the surface of the selectively permeable membrane for attachment to the skin or mucosa.
Claim 15
Dependent Claim
11 words
A system according to claim 3 wherein the drug is sulindac.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |