Piroxicam Capsules

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Piroxicam Capsules contain NLT 92.5% and NMT 107.5% of the labeled amount of piroxicam (C₁₅H₁₃N₃O₄S).

2 IDENTIFICATION

A. Thin-Layer Chromatography

Diluent: Chloroform and methanol (1:1)

Standard solution: 1 mg/mL of USP Piroxicam RS in Diluent

Sample solution: Dissolve a portion of the contents of Capsules in Diluent to obtain a solution containing about 1 mg/mL. Shake by mechanical means for 10 min, and filter a portion. Use the filtrate for the analysis.

Chromatographic system

(See Chromatography 〈621〉, Thin-Layer Chromatography.)

Absorbent: 0.25-mm layer of chromatographic silica gel

Application volume: 20 μL

Developing solvent system: Toluene and glacial acetic acid (95:5)

Analysis

Samples: Standard solution and Sample solution

Allow the spots to dry, and develop the chromatogram in the Developing solvent system until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, and air-dry. Place the plate in the developing chamber, and develop as before. Remove the plate from the chamber, mark the solvent front, and air-dry. Locate the spots on the plate by viewing under short-wavelength UV light.

Acceptance criteria: The R value of the principal spot of the Sample solution corresponds to that of the Standard solution.

3 ASSAY

Procedure

Solution A: Dissolve 7.72 g of anhydrous citric acid in 400 mL of water.

Solution B: Dissolve 5.35 g of dibasic sodium phosphate in 100 mL of water.

Solution C: Add Solution B to Solution A, and dilute with water to make 1000 mL.

Mobile phase: Methanol and Solution C (450:550)

Diluent: 0.01 N methanolic hydrochloric acid

Standard stock solution: 0.25 mg/mL of USP Piroxicam RS in Diluent

Standard solution: 0.05 mg/mL of USP Piroxicam RS prepared as follows. Transfer 10.0 mL of Standard stock solution to a 50-mL volumetric flask, add 25 mL of Diluent and 10.0 mL of water, and dilute with Diluent to volume.

Sample stock solution: Transfer, as completely as possible, the contents of NLT 20 Capsules to a suitable tared container, and determine the average weight per capsule. Mix the combined contents, and transfer an amount nominally equivalent to about 50 mg of piroxicam to a 100-mL volumetric flask. Add about 70 mL of Diluent, and shake by mechanical means for 30 min. Dilute with Diluent to volume, and mix.

Centrifuge a portion of this mixture to obtain a clear solution.

Sample solution: Transfer 10.0 mL of the Sample stock solution to a 100-mL volumetric flask, add about 50 mL of Diluent and 20.0 mL of water, dilute with Diluent to volume, and mix.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 3.9-mm × 30-cm; packing L1

Flow rate: 1.2 mL/min

Injection volume: 25 μL

System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 500 theoretical plates

Tailing factor: NMT 1.5

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of piroxicam (C₁₅H₁₃N₃O₄S) in the portion of Capsules taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Piroxicam RS in the Standard solution (mg/mL)

C_U = nominal concentration of piroxicam in the Sample solution (mg/mL)

Acceptance criteria: 92.5% - 107.5%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: Simulated gastric fluid TS, prepared without pepsin; 900 mL

Apparatus 1: 50 rpm

Time: 45 min

Standard stock solution: 0.5 mg/mL of USP Piroxicam RS in methanol

Standard solution: A known concentration of USP Piroxicam RS in Medium from Standard stock solution. Dilute with Medium, if necessary.

Sample solution: Filter a portion of the solution under test, suitably dilute with Medium, if necessary.

[Note - Use a suitable filter that does not adsorb piroxicam.]

Instrumental conditions

Mode: UV

Analytical wavelength: Maximum at about 333 nm

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of piroxicam (C₁₅H₁₃N₃O₄S) dissolved by comparing the UV absorbance of Sample solution with that of Standard solution.

Tolerances: NLT 75% (Q) of the labeled amount of piroxicam (C₁₅H₁₃N₃O₄S) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 SPECIFIC TESTS

Water Determination, Method I〈921〉: NMT 8.0%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

USP Reference Standards 〈11〉

USP Piroxicam RS