US4687518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for manufacturing pyrogen-free collagen gels useful as contact lenses
Assignee: VISION 2000 TECHNOLOGIES Inc
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Filing: 1985-11-06
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Granted: 1987-08-18
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Expires: 2005-11-06
Abstract
Abstract Pyrogen-free collagen useful for manufacturing soft contact lenses is made by performing all manufacturing process steps under aseptic conditions.
Inventors
- 👤 Teruo Miyata
- 👤 Albert L. Rubin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:24
CPC Classifications
C; C08; C08L; C08L89/00; C08L89/04; C08L89/06; G; G02; G02B; G02B1/00; G02B1/04; G02B1/041; G02B1/043
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
134 words
A method for manufacturing a pyrogen-free atelocollagen gel for use in soft contact lenses which comprises the following aseptic steps: (1) removing the corium layer from animal skin under aseptic condition; (2) washing said corium layer with a sterile pyrogen-free salt solution to remove soluble substances other than collagen; (3) grinding and dissolving the collagen with an acidic proteolytic enzyme in a sterile and pyrogen-free condition; (4) filtering the dissolved collagen solution through a membrane filter to obtain a clear filtrate; (5) neutralizing the filtrate with a strong base to precipitate atelocollagen; (6) washing the precipitated atelocollagen with an organic solvent to remove lipid; (7) drying the atelocollagen precipitate; (8) dissolving the dried atelocollagen in an aqueous solution to a concentration of from 1% to 10% to make a gel for contact lens manufacture.
Claim 2
Independent Claim
134 words
A method for manufacturing a pyrogen-free atelocollagen gel for use in soft contact lenses which comprises the following aseptic steps: (1) removing the corium layer from animal skin under aseptic condition; (2) washing said corium layer with a sterile pyrogen-free salt solution to remove soluble substances other than collagen; (3) grinding and dissolving the collagen with an acidic proteolytic enzyme in a sterile and pyrogen-free condition; (4) filtering the dissolved collagen solution through a membrane filter to obtain a clear filtrate; (5) neutralizing the filtrate with a strong base to precipitate atelocollagen; (6) washing the precipitated atelocollagen with an organic solvent to remove lipid; (7) drying the atelocollagen precipitate; (8) dissolving the dried atelocollagen in an aqueous solution to a concentration of from 1% to 10% to make a gel for contact lens manufacture.
Claim 3
Dependent Claim
15 words
A method according to claim 1, wherein said skin is bovine, sheep or porcine hide.
Claim 4
Dependent Claim
30 words
A method according to claim 1, wherein said aqueous solution and water used for washing, enzyme solubilization and making the collagen gel for lens preparation are sterile and pyrogen free.
Claim 5
Dependent Claim
33 words
A method according to claim 1, wherein said acidic proteolylic enzyme is selected from the group consisting of pepsin and enzymes obtained from micro organisms having an optimum pH of less than 4.5.
Claim 6
Dependent Claim
20 words
A method according to claim 1, wherein said membrane filter has a pore size of from 0.4 to 0.8 micron.
Claim 7
Dependent Claim
46 words
A method according to claim 1, wherein the dried atelocollagen precipitate is sterilized using an ethylene oxide gas treatment, such treatment being performed by introducing said gas into a vacuum container in which said dried atelocollagen is placed at room temperature for more than 10 hours.
Claim 8
Dependent Claim
23 words
A method according to claim 1, wherein said atelocollagen gel for contact lens manufacturing is at pH 2.0 to 4.5, transparent and pyrogen-free.
Claim 9
Dependent Claim
15 words
A clear, transparent pyrogen-free lens prepared from collagen prepared by the method of claim 1.
References Cited (Backward Citations)
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US4204992A
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US4260228A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-17 | 1991-02-16 | 1991-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-17 | 1995-02-16 | 1995-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-17 | 1999-02-16 | 1999-08-18 | $7700.00 | Window Closed / Lapsed |