Blank— Prepare as directed for the Assay preparation, without adding Piroxicam. Use Purified Water to offset the difference in weight between the Blank and the Assay preparation. Pass the solution through a 0.45-µm filter, and discard the first 5 mL of the filtrate.
Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 254-nm detector, a 4.6-mm × 30-cm analytical column that contains 10-µm packing L1, and a 4.6-mm × 2-cm guard column that contains packing L1. The flow rate is about 1.0 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the retention time is about 7 minutes, and the relative standard deviation for replicate injections is not more than 2.8%.
Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation, the Assay preparation, and the Blank into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of piroxicam (C15H13N3O4S) in each mL of Piroxicam Cream taken by the formula:
200(C/V)(rU / rS)
in which C is the concentration, in µg per mL, of USP Piroxicam RS in the Standard preparation; V is the volume, in mL, of liquid taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.USP31
Piroxicam cream มีวิธีการ Analysis อย่างไรบ้าง จาก USP 36 จากวิธีการ Blank, Chromatographic และ Procedure ใครแปลได้บ้าง
Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 254-nm detector, a 4.6-mm × 30-cm analytical column that contains 10-µm packing L1, and a 4.6-mm × 2-cm guard column that contains packing L1. The flow rate is about 1.0 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the retention time is about 7 minutes, and the relative standard deviation for replicate injections is not more than 2.8%.
Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation, the Assay preparation, and the Blank into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of piroxicam (C15H13N3O4S) in each mL of Piroxicam Cream taken by the formula:
200(C/V)(rU / rS)
in which C is the concentration, in µg per mL, of USP Piroxicam RS in the Standard preparation; V is the volume, in mL, of liquid taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.USP31