Control of pH in aqueous urea-containing solutions utilizing amino acid-containing compositions
AssigneeSiemens Healthcare Diagnostics Inc.
InventorsLaura Uretsky, Kevin Horan
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Abstract
Aqueous calibration or quality control reagents that include urea are disclosed; the reagents may further include at least one amino acid-containing composition to provide pH stability thereto. Methods of production and use thereof are also disclosed.
Claims22
A composition comprising an aqueous diagnostic quality control or calibration reagent disposed in a closed system, the composition comprising:
- urea present in a concentration in a range of from about 0.1 mM to about 150 mM;
- at least one buffer;
- and
- ornithine, wherein a ratio of urea to ornithine is in a range of from about 0.1:1 to about 100:1;
- and
- wherein the pH of the aqueous quality control or calibration reagent varies by +/−1.0 or less of the original pH following storage of the composition, and further wherein formation of ammonia in the aqueous diagnostic quality control or calibration reagent is substantially reduced by at least 5% following storage of the composition when compared to a composition prepared in the absence of ornithine and following storage thereof;
- and
- wherein the aqueous diagnostic quality control or calibration reagent is for utilization with a diagnostic sensor.
A composition comprising an aqueous diagnostic quality control or calibration reagent disposed in a closed system, the composition comprising:
- urea present in a concentration in a range of from about 0.1 mM to about 150 mM;
- at least one buffer;
- and
- an amino acid-containing composition having at least one available primary or secondary amine, the amino acid-containing composition comprising ornithine and at least one additional amino acid, wherein a ratio of urea to the amino acid-containing composition is in a range of from about 0.1:1 to about 100:1;
- and
- wherein the pH of the aqueous quality control or calibration reagent varies by +/−1.0 or less of the original pH following storage of the composition, and further wherein formation of ammonia in the aqueous diagnostic quality control or calibration reagent is substantially reduced by at least 5% following storage of the composition when compared to a composition prepared in the absence of the amino acid-containing composition and following storage thereof;
- and
- wherein the aqueous diagnostic quality control or calibration reagent is for utilization with a diagnostic sensor.
A method of stabilizing the pH of an aqueous diagnostic quality control or calibration reagent containing urea and at least one buffer, wherein an original urea concentration of the aqueous diagnostic quality control or calibration reagent is in a range of from about 0.1 mM to about 150 mM, the method comprising the step of:
- disposing an amino acid-containing composition having at least one available primary or secondary amine into the aqueous diagnostic quality control or calibration reagent, the amino acid-containing composition comprising ornithine and at least one additional amino acid, wherein the amino acid-containing composition is disposed into the aqueous diagnostic quality control or calibration reagent such that a ratio of urea to the amino acid-containing composition is in a range of from about 0.1:1 to about 100:1, and whereby the pH of the aqueous quality control or calibration reagent varies by +/−1.0 or less of the original pH following storage of the composition, and further wherein formation of ammonia in the aqueous diagnostic quality control or calibration reagent is substantially reduced by at least 5% following storage of the composition when compared to a composition prepared in the absence of the amino acid-containing composition and following storage thereof;
- and
- wherein the aqueous diagnostic quality control or calibration reagent is for utilization with a diagnostic sensor.
Dependencies are inferred from the claim text.