Control of pH in aqueous urea-containing solutions utilizing amino acid-containing compositions
AssigneeSiemens Healthcare Diagnostics Inc.
InventorsLaura Uretsky, Kevin Horan
Life of this patent
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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.
Claims19
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
- asparagine, wherein a ratio of urea to asparagine is in a range of from about 0.1:1 to about 100:1;
- and
- wherein an original pH of the aqueous quality control or calibration reagent is in a range of from about 6 to about 8, 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 asparagine and following storage thereof;
- and
- wherein the aqueous diagnostic quality control or calibration reagent is brought into direct contact with a diagnostic sensor for calibration or quality control of the 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 asparagine into the aqueous diagnostic quality control or calibration reagent such that a ratio of urea to asparagine is in a range of from about 0.1:1 to about 100:1,
- wherein an original pH of the aqueous quality control or calibration reagent is in a range of from about 6 to about 8, 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 asparagine and following storage thereof;
- and
- wherein the aqueous diagnostic quality control or calibration reagent is brought into direct contact with a diagnostic sensor for calibration or quality control of the diagnostic sensor.
A composition comprising an aqueous diagnostic quality control or calibration reagent for calibration or quality control of a blood urea nitrogen (BUN) or creatinine sensor, wherein the aqueous diagnostic quality control or calibration reagent is 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;
- asparagine, wherein a ratio of urea to asparagine is in a range of from about 0.1:1 to about 100:1;
- and
- wherein the aqueous diagnostic quality control or calibration reagent is free of protein;
- wherein an original pH of the aqueous quality control or calibration reagent is in a range of from about 6 to about 8, 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 asparagine and following storage thereof;
- and
- wherein the aqueous diagnostic quality control or calibration reagent is brought into direct contact with the BUN or creatinine sensor for calibration or quality control of the BUN or creatinine sensor.
Dependencies are inferred from the claim text.