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Details for Patent: 6,140,321

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Summary for Patent: 6,140,321

Title: Polymorphs of donepezil hydrochloride and process for production
Abstract:Donepezil hydrochloride, 1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-yl]methylpiperidine hydrochloride, is provided here in the form of four polymorphs which are stable against heat and humidity in the pharmaceutical use. They can be industrially produced. They are specified by peaks in X-ray powder diffraction pattern and absorption peaks in infrared absorption spectra in potassium bromide.
Inventor(s): Imai; Akio (Ibaraki, JP), Watanabe; Hideaki (Ibaraki, JP), Kajima; Takashi (Ibaraki, JP), Ishihama; Yasushi (Ibaraki, JP), Ohtsuka; Akiyo (Ibaraki, JP), Tanaka; Tomohide (Ibaraki, JP)
Assignee: Eisai Co., Ltd. (Tokyo, JP)
Application Number:08/774,802
Patent Claim Types:
see list of patent claims
Compound; Process; Use; Composition;
Patent Metrics:
Source: PatentQuant.com
Field: Basic materials chemistry
Back Citations: 2nd percentile
Forward Citations: 1st percentile

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Premature patent expiration for: 6,140,321

Expiration due to failure to pay maintenance fee

Patent Number Expiration Date
6,140,321 October 31, 2008

Foreign Priority and PCT Information for Patent: 6,140,321

Foriegn Application Priority Data
Foreign Country Foreign Patent Number Foreign Patent Date
Japan8-146293Jun 07, 1996

International Patent Family for Patent: 6,140,321

Country Document Number Estimated Expiration Supplementary Protection Certificate SPC Country SPC Expiration
Hong Kong1080078<disabled in preview>
Hungary0002270<disabled in preview>
Hungary227539<disabled in preview>
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The estimated expiration dates shown above are derived by simply adding 20 years to the priority date.
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