ASSAY Calibration solutions Calibration solutions of naproxen in the range 5 – 25 μg/mL were prepared. Sample preparation 20 tablets weighing 12.3819 g were crushed to a fine powder. A portion of the powder (145.4 mg) was shaken with approximately 150 mL of acetic acid (0.05 M) for 5 min and then made up to volume in a 250 mL volumetric flask (stock solution). Approximately 50 mL of the stock solution was filtered and a 25 mL aliquot was diluted to 100 mL in a volumetric flask. 10 mL of the resulting solution was further diluted to 100 mL with acetic acid (0.05 M). Analysis The standards and sample solutions were analyzed by HPLC under the following conditions: Column: octadecylsilyl (ODS), 4.6 mmx150 mm, mobile phase: acetonitrile : 0.05 M acetic acid (85:15), flow rate: 1 ml/min, UV detection at 243 nm. Results: A calibration curve of concentration versus peak area was constructed for the standard solutions and gave the straight-line equation: y = 3555.6x + 85, r = 0.9999 The area of the naproxen sample peak = 45204 Stated content = 500 mg Calculate: a) The concentration of naproxen in the diluted sample solution analyzed Calculate the answer by read surrounding text. μg/mL (2 decimal places) b) The actual amount of naproxen (in mg) in the assay powder weighed out. Calculate the answer by read surrounding text. mg (1 decimal place) c) The actual amount of naproxen (in mg) per tablet. . Calculate the answer by read surrounding text. mg (1 decimal place) d) The percentage of stated content of per tablet. Calculate the answer by read surrounding text. (1 decimal place)
ASSAY
Calibration solutions
Calibration solutions of naproxen in the range 5 – 25 μg/mL were prepared.
Sample preparation
20 tablets weighing 12.3819 g were crushed to a fine powder. A portion of the powder (145.4 mg) was shaken with approximately 150 mL of acetic acid (0.05 M) for 5 min and then made up to volume in a 250 mL volumetric flask (stock solution). Approximately 50 mL of the stock solution was filtered and a 25 mL aliquot was diluted to 100 mL in a volumetric flask. 10 mL of the resulting solution was further diluted to 100 mL with acetic acid (0.05 M).
Analysis
The standards and sample solutions were analyzed by HPLC under the following conditions:
- Column: octadecylsilyl (ODS), 4.6 mmx150 mm,
- mobile phase: acetonitrile : 0.05 M acetic acid (85:15),
- flow rate: 1 ml/min,
- UV detection at 243 nm.
Results:
- A calibration curve of concentration versus peak area was constructed for the standard solutions and gave the straight-line equation: y = 3555.6x + 85, r = 0.9999
- The area of the naproxen sample peak = 45204
-
Stated content = 500 mg
Calculate:
a) The concentration of naproxen in the diluted sample solution analyzed
Calculate the answer by read surrounding text. μg/mL (2 decimal places)
b) The actual amount of naproxen (in mg) in the assay powder weighed out.
Calculate the answer by read surrounding text. mg (1 decimal place)
c) The actual amount of naproxen (in mg) per tablet.
. Calculate the answer by read surrounding text. mg (1 decimal place)
d) The percentage of stated content of per tablet.
Calculate the answer by read surrounding text. (1 decimal place)
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