US5017518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing calcium phosphate ceramics having porous surface
Assignee: Pentax Corp
•
Filing: 1990-04-18
•
Granted: 1991-05-21
•
Expires: 2010-04-18
Abstract
Abstract A process for producing calcium phosphate ceramics having a porous surface is described, which comprise the steps of: a) preparing untreated calcium phosphate ceramics, which comprises a mixture of hydroxyapatite and tricalcium phosphate, and b) treating said untreated ceramics with an acidic solution to selectively dissolve the tricalcium phosphate in the surface of the ceramics.
Inventors
- 👤 Yasuhiko Hirayama
- 👤 Tetsuro Ogawa
- 👤 Satoshi Ojima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:42
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/447; A; A61; A61K; A61K6/00; A61K6/50; A61K6/58; A61K6/70; A61K6/71; A61K6/74; A61K6/75; A61K6/80; A61K6/849; A61K6/864; A61L; A61L27/00; A61L27/02; A61L27/12; B; B01; B01J; B01J20/00; B01J20/02; B01J20/04; B01J20/048; B01J20/28; B01J20/28054; B01J20/28078; B01J20/30; B01J20/3078; B01J20/3085; C04B38/00; C04B38/04; C04B41/00; C04B41/009; C04B41/53; C04B41/5338; C04B41/5353; C04B41/80; C04B41/91; A61F; A61F2310/00; A61F2310/00005; A61F2310/00179; A61F2310/00293
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
82 words
A process for producing calcium phosphate ceramics having a porous surface, comprising the steps of: a) preparing untreated calcium phosphate ceramics, said untreated ceramics comprising a mixture of hydroxyapatite and tricalcium phosphate; b) molding said untreated ceramics; c) firing said untreated ceramics; and d) contacting said untreated ceramics with an acidic solution to selectively dissolve the tricalcium phosphate in the surface of the ceramics but not selectively dissolve said hydroxyapatite; wherein the pH of the acidic solution is from 1 to 5.5.
Claim 2
Dependent Claim
82 words
A process for producing calcium phosphate ceramics having a porous surface, comprising the steps of: a) preparing untreated calcium phosphate ceramics, said untreated ceramics comprising a mixture of hydroxyapatite and tricalcium phosphate; b) molding said untreated ceramics; c) firing said untreated ceramics; and d) contacting said untreated ceramics with an acidic solution to selectively dissolve the tricalcium phosphate in the surface of the ceramics but not selectively dissolve said hydroxyapatite; wherein the pH of the acidic solution is from 1 to 5.5.
Claim 3
Dependent Claim
42 words
A process for producing calcium phosphate ceramics having a porous surface as claimed in claim 1, wherein the mixture of hydroxyapatite and tricalcium phosphate is controlled to give a calcium to phosphorus molar ratio (Ca/P) in the range from 1.53/1 to 1.64/1.
Claim 4
Dependent Claim
42 words
A process for producing calcium phosphate ceramics having a porous surface as claimed in claim 2, wherein the mixture of hydroxyapatite and tricalcium phosphate is controlled to give a calcium to phosphorus molar ratio (Ca/P) in the range from 1.57/1 to 1.64/1.
Claim 5
Dependent Claim
29 words
A process for producing calcium phosphate ceramics having a porous surface as claimed in claim 1, wherein the firing is at a temperature of from 700° to 1,400° C.
Claim 6
Dependent Claim
29 words
A process for producing calcium phosphate ceramics having a porous surface as claimed in claim 4, wherein the firing is at a temperature of from 1,000° to 1,300° C.
Claim 7
Dependent Claim
39 words
A process for producing calcium phosphate ceramics having a porous surface according to claim 8, wherein said step of contacting untreated ceramic with an acidic solution is performed for a time period of from 1 second to 24 hours.
Claim 8
Dependent Claim
93 words
Calcium phosphate based ceramics having a porous surface produced by the process comprising the steps of: a) preparing untreated calcium phosphate ceramics, said untreated ceramics comprising a mixture of hydroxyapatite and tricalcium phosphate; b) molding said untreated ceramics; c) firing said untreated ceramics; and d) contacting said untreated ceramics with an acidic solution to selectively dissolve the tricalcium phosphate in the surface of the ceramics but not selectively dissolve said hydroxyapatite so that the inner density of said ceramics is maintained; wherein the pH of the acidic solution is from 1 to 5.5.
Claim 9
Dependent Claim
93 words
Calcium phosphate based ceramics having a porous surface produced by the process comprising the steps of: a) preparing untreated calcium phosphate ceramics, said untreated ceramics comprising a mixture of hydroxyapatite and tricalcium phosphate; b) molding said untreated ceramics; c) firing said untreated ceramics; and d) contacting said untreated ceramics with an acidic solution to selectively dissolve the tricalcium phosphate in the surface of the ceramics but not selectively dissolve said hydroxyapatite so that the inner density of said ceramics is maintained; wherein the pH of the acidic solution is from 1 to 5.5.
References Cited (Backward Citations)
US3929971A
Cited
US4207306A
Cited
US4308064A
Cited
US4371484A
Cited
JPS5883605A
Cited
JPS59182263A
Cited
US4626392A
Cited
US4693986A
Cited
JPS62153204A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-05-20 | 1994-11-19 | 1995-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-20 | 1998-11-19 | 1999-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-20 | 2002-11-19 | 2003-05-21 | $7700.00 | Window Closed / Lapsed |