US4091087A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Folic acid derivatives and use in radio-assay
Assignee: SmithKline Instrument Inc
•
Filing: 1976-07-28
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Granted: 1978-05-23
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Expires: 1996-07-28
Abstract
Abstract Novel folic acid derivatives useful for radioassaying 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
2026-11-03 14:17
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: 7
Claim 1
Independent Claim
94 words
In a radioassay kit for radioassaying a specimen for folic acid, its metabolites or derivatives which bind to β-lactoglobin and contains vials of: (a) N 5 -methyltetrahydrofolic acid as a standard; (b) lysine buffer; (c) bovine serum albumin as a standard diluent; (d) β-lactoglobin; (e) isotope diluent; (f) dextran; and (g) charcoal powder, the improvement which comprises the addition in a vial a chemical compound of the formula: ##STR4## wherein n is a positive integer of from 1 to 3 and R is radioactive iodine: I 125 or I 131 ; to said kit.
Claim 2
Dependent Claim
94 words
In a radioassay kit for radioassaying a specimen for folic acid, its metabolites or derivatives which bind to β-lactoglobin and contains vials of: (a) N 5 -methyltetrahydrofolic acid as a standard; (b) lysine buffer; (c) bovine serum albumin as a standard diluent; (d) β-lactoglobin; (e) isotope diluent; (f) dextran; and (g) charcoal powder, the improvement which comprises the addition in a vial a chemical compound of the formula: ##STR4## wherein n is a positive integer of from 1 to 3 and R is radioactive iodine: I 125 or I 131 ; to said kit.
Claim 3
Dependent Claim
17 words
The radioassay kit of claim 1 in which n is 1 and R is I 125 .
Claim 4
Dependent Claim
89 words
In a method of radioassaying a specimen for folic acid, its metabolites or derivatives which bind to β-lactoglobin and employs as assay material: (a) lysine buffer; (b) isotope solution; (c) β-lactoglobin; (d) dextran; and (e) charcoal powder; the improvement which comprises adding to said assay material a chemical compound of the formula: ##STR5## wherein n is a positive integer of from 1 to 3 and R is radioactive iodine: I 125 or I 131 ; counting for radioactivity and comparing the count with that obtained from a standard curve.
Claim 5
Dependent Claim
89 words
In a method of radioassaying a specimen for folic acid, its metabolites or derivatives which bind to β-lactoglobin and employs as assay material: (a) lysine buffer; (b) isotope solution; (c) β-lactoglobin; (d) dextran; and (e) charcoal powder; the improvement which comprises adding to said assay material a chemical compound of the formula: ##STR5## wherein n is a positive integer of from 1 to 3 and R is radioactive iodine: I 125 or I 131 ; counting for radioactivity and comparing the count with that obtained from a standard curve.
Claim 6
Dependent Claim
17 words
The method of claim 3 in which the radioactivity is determined by using a gamma scintillation spectrometer.
Claim 7
Dependent Claim
16 words
The method of claim 3 in which n is 1 and R is I 125 .
References Cited (Backward Citations)
US3988431A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |