US3939831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing medicinal dressings
Assignee: Intreprinderea Flacara Rosie
•
Filing: 1974-03-04
•
Granted: 1976-02-24
•
Expires: 1994-03-04
Abstract
Abstract Collagen-based medicinal dressings are produced by freezing a collagen aqueous polydispersion obtained from cattle hide in a concentration of 0.66 to 2% by weight at a temperature of at most -65°C and subjecting the frozen polydispersion to vacuum at a pressure of 10 - 3 to 10 - 5 torr for a period of 24 to 48 hours while maintaining a temperature thereof of at most +35°C. The resulting spongy mass has a density of 0.03 to 0.06 gram/cm 3 .
Inventors
- 👤 Gheorghe Cioca
- 👤 Nicolae Tigaeru
- 👤 Agrippa Ionescu
- 👤 Nicolae Chiotan
- 👤 Mihai Constantinescu
- 👤 Gheorghe Niculescu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 16:30
CPC Classifications
A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/425; A61L15/22; A61L15/32; A61L15/325; Y; Y10; Y10S; Y10S128/00; Y10S128/08; Y10S602/00; Y10S602/90
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
78 words
A method of making a collagen-based medicinal dressing comprising the steps of: freezing a collagen polydispersion containing a bacteriocide, bacteriostat or healing-promotion agent in water to a temperature between -65°C and -70°C for a period of 2.5 to 3.2 hours, drying the frozen polydispersion by vacuum sublimation over a period of substantially 24 to 48 hours at a pressure of 10.sup. -3 to 10.sup. -5 torr, and maintaining the temperature during the vacuum sublimation period up to +35°C.
Claim 2
Independent Claim
78 words
A method of making a collagen-based medicinal dressing comprising the steps of: freezing a collagen polydispersion containing a bacteriocide, bacteriostat or healing-promotion agent in water to a temperature between -65°C and -70°C for a period of 2.5 to 3.2 hours, drying the frozen polydispersion by vacuum sublimation over a period of substantially 24 to 48 hours at a pressure of 10.sup. -3 to 10.sup. -5 torr, and maintaining the temperature during the vacuum sublimation period up to +35°C.
Claim 3
Dependent Claim
17 words
The method defined in claim 1 wherein said polydispersion has a collagen concentration of 0.66 to 2%.
Claim 4
Dependent Claim
21 words
The method defined in claim 2 wherein 0.5 to 2 grams of tetracycline is added per 1000 ml of the polydispersion.
Claim 5
Dependent Claim
21 words
The method defined in claim 2 wherein 0.5 to 0.75 grams of hydrocortisone is added per 1000 ml of the polydispersion.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-23 | 1979-08-25 | 1980-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-23 | 1983-08-25 | 1984-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-23 | 1987-08-25 | 1988-02-24 | $7700.00 | Window Closed / Lapsed |