US3989812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Folic acid derivatives and use in radio-assay
Assignee: SmithKline Instrument Inc
•
Filing: 1974-08-09
•
Granted: 1976-11-02
•
Expires: 1994-08-09
Abstract
Abstract Novel folic acid derivatives useful for radio-assaying folic acid and its metabolites in biological liquids are prepared from pteroyl-γ-glutamyl-tyrosines by iodination with I 125 or I 131 .
Inventors
- 👤 M. James Barrett
- 👤 Joseph I. De Graw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:28
CPC Classifications
C; C07; C07D; C07D475/00; C07D475/02; C07D475/04; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/82
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
18 words
A chemical compound of the formula: ##SPC4## wherein R is radioactive iodine: I 125 or I 131 .
Claim 2
Dependent Claim
18 words
A chemical compound of the formula: ##SPC4## wherein R is radioactive iodine: I 125 or I 131 .
Claim 3
Dependent Claim
14 words
A chemical compound according to claim 1 in which R is I 125 .
Claim 4
Dependent Claim
31 words
In a radioassay material for radioassaying a specimen for folic acid, its metabolites or derivatives which bind to β-lactoglobin, the improvement which comprises employing therein a chemical compound of claim 1.
Claim 5
Dependent Claim
12 words
The material of claim 3 in which R is I 125 .
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-11-02 | 1980-05-03 | 1980-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-02 | 1984-05-03 | 1984-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-02 | 1988-05-03 | 1988-11-02 | $7700.00 | Window Closed / Lapsed |