Method for increasing shelf-life of a serum bilirubin reference composition and composition produced thereby

• US 4,288,343 A
• Filed: 03/22/1979
• Issued: 09/08/1981
• Est. Priority Date: 07/17/1978
• Status: Expired due to Term

• Current Assignee: Beckman Instruments, Inc. (Danaher Corporation)
• Original Assignee: Beckman Instruments, Inc. (Danaher Corporation)
• Inventors: Louderback, Allan L.
• Primary Examiner(s): Gron, Teddy S.
• Application Number:
  US06/022,567
• Time in Patent Office: 901 Days
• Field of Search: 252/408, 23/230 B, 23/905, 424/2, 424/3
• US Class Current: 436/12
• CPC Class Codes: G01N 33/72 involving blood pigments, e.g. haemoglobin, bilirubin or other porphyrins; involving occult blood
• CPC Class Codes: G01N 33/96 involving blood or serum control standard
• CPC Class Codes: Y10T 436/103332 Bilirubin or uric acid standard or control
• CPC Class Codes: Y10T 436/146666 Bile pigment

Abstract

A stable blood serum bilirubin reference composition characterized in that the composition possess a pH of from about 8.2 to about 9.2 and comprises (a) a sulfhydryl compound in an amount sufficient to enhance the stability of the bilirubin and (b) a chelating agent in an amount sufficient to bind all the metals present in the blood serum moiety of the composition. This blood serum bilirubin composition when stored in a gas impervious vial under an inert atmosphere has an excellent shelf life.

Claims

1. An improved blood serum reference composition of the type comprising blood serum having a bilirubin constituent of known value, characterized in that said composition possesses a pH of from about 8.2 to about 9.2 and further comprises:

(a) a sulfhydryl compound in an amount sufficient to further enhance the stability of bilirubin and

(b) a chelating agent in an amount sufficient to bind the metals present in said blood serum.

2. The composition of claim 1 wherein said sulfhydryl compound is present in an amount such that the oxidation-reduction potential of said composition is from about -30 to about -300 millivolts and wherein said composition comprises from about 25 to about 1,000 mg chelating agent per 100 ml serum.

3. The composition of claim 1 wherein said sulfhydryl compound is present in an amount such that the oxidation-reduction potential of said composition is from about -100 to about -200 millivolts, wherein said composition comprises from about 50 to about 150 mg chelating agent per 100 ml serum, and wherein said composition possesses a pH of from about 8.4 to about 8.9.

4. The composition of claim 3 wherein said sulfhydryl compound is present in an amount such that the oxidation-reduction potential of said composition is about -160 millivolts, wherein said composition comprises about 100 mg chelating agent per 100 ml serum, and wherein said composition possesses a pH of about 8.7.

5. The composition of claim 4 wherein said sulfhydryl compound is selected from a group consisting of dithioerythreitol, dithiothreitol, mercaptrethanol, cysteine, reduced gluthione, N-acetyl cysteine, mercaptoacetate, and mixtures thereof, and wherein said chelating agent is selected from a group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, ethylenediamino, diethylenetriamine, triethyltetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethyliminodiacetic acid, N-hydroxyethyl-N,N'"'"',N'"'"', ethylenediaminitriacetic acid, N,N,N'"'"',N",N"-diethylenetriaminepentaacetic acid, citric acid, tartanic acid, gluconic acid, tripolyphosphate ion, polyphosphate anion, N,N'"'"'-ethylenebis[2-(o-hydroxyphenyl]glycine, 3,5-disulfopyrocatechol, bis-(orthohydroxybenzyl)ethylenediamine-N,N'"'"'-diacetic acid, salts thereof, and mixtures thereof.

6. The composition of claim 5 wherein said sulfhydryl compound is dithiothreitol and wherein said chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid, salts thereof, and mixtures thereof.

13. An article comprising a gas impervious container having located therein an inert gas and the composition of any one of claims 1-11 or 12.

14. An article comprising a gas impervious container which is also impervious to visible light and having located therein an inert gas and the composition of any one of claims 1-11 or 12.

7. An improved bilirubin reference composition comprising in its non-biological component from about 60 to about 80 weight percent water, from about 20 to about 40 weight percent of at least one alkylene polyol having from 2 to 5 carbon atoms, the remainder being bilirubin and, optionally, other natural biological materials selected from a group consisting of blood serum, enzymes, metabolites, electrolytes, and hormones, characterized in that said composition possesses a pH of from about 8.2 to about 9.2 and further comprises:

(a) a sulfhydryl compound in an amount sufficient to further enhance the stability of bilirubin and

(b) a chelating agent in an amount sufficient to bind the metals present in said blood serum.

8. The composition of claim 7 wherein said sulfhydryl compound is present in an amount such that the oxidation-reduction potential of said composition is from about -30 to about -300 millivolts and wherein said composition comprises from about 25 to about 1,000 mg chelating agent per 100 ml serum.

9. The composition of claim 7 wherein said sulfhydryl compound is present in an amount such that the oxidation-reduction potential of said composition is from about -100 to about -200 millivolts, wherein composition comprises from about 50 to about 150 mg chelating agent per 100 ml serum, and wherein said composition possesses a pH of from about 8.4 to about 8.9.

10. The composition of claim 9 wherein said sulfhydryl compound is present in an amount such that the oxidation-reduction potential of said composition is about -160 millivotls, wherein said composition comprises about 100 mg chelaying agent per 100 ml serum, and wherein said composition possesses a pH of about 8.7.

11. The composition of claim 10 wherein said sulfhydryl compound is selected from a group consisting of dithioerythreitol, dithiothreitol, mercaptrethanol, cysteine, reduced gluthione, N-acetyl cysteine, mercaptoacetate, and mixtures thereof, and wherein said chelating agent is selected from a group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, ethylenediamino, diethylenetriamine, triethyltetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethyliminodiacetic acid, N-hydroxyethyl-N,N'"'"',N'"'"',ethylenediamietriacetic acid, N,N,N'"'"',N",N"-diethylenetriaminepentaacetic acid, citric acid, tartanic acid, gluconic acid, tripolyphosphate ion, polyphosphate anion, N,N'"'"'-ethylenebis[2-(o-hydroxyphenyl]glycine, 3,5-disulfopyrocatechol, bis-(orthohydroxybenzyl)ethylenediamine-N,N'"'"'-diacetic acid, salts thereof, and mixtures thereof.

12. The composition of claim 7 wherein said sulfhydryl compound is dithiothreitol and wherein said chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid, salts thereof, and mixtures thereof.