Piroxicam Compounded Cream

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

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

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1 DEFINITION

Piroxicam Compounded Cream contains NLT 90.0% and NMT 110.0% of the labeled amount of piroxicam (C₁₅H₁₃N₃O₄S).

Prepare Piroxicam Compounded Cream as follows (see Pharmaceutical Compounding - Nonsterile Preparations 〈795〉).

In an appropriate container ( final weight tared), mix the White Petrolatum and Stearyl Alcohol together, and heat to 80 ± 5° to form a clear oil phase. In a separate container, mix the Propylparaben, Methylparaben, Propylene Glycol, Sodium Lauryl Sulfate, and about 30 mL of Purified Water together, and heat to 80 ± 5° to form a clear aqueous phase. Add the aqueous phase to the oil phase with continuous stirring, and allow it to cool to 50° to form an emulsion. In a mortar, triturate the Piroxicam with the Sodium Hydroxide to form a suspension. Using additional Purified Water to rinse the mortar, add the piroxicam suspension to the previously prepared emulsion, transferring the suspension stepwise and quantitatively to the emulsion. Add suficient Purified Water with stirring to bring to final weight. Package, and label.

2 ASSAY

Procedure

Solution A: 2.7 g/L of citric acid and 5.4 g/L of dibasic sodium phosphate in Purified Water. Pass through a filter of 0.45-μm pore size.

Mobile phase: Methanol and Solution A (50:50). Filter, and degas.

Diluent: 0.01 N methanolic hydrochloric acid prepared by diluting 0.9 mL of hydrochloric acid with methanol to a final volume of 1 L

Standard solution: Dissolve an accurately weighed quantity of USP Piroxicam RS in 2 mL of chloroform, and dilute with Diluent to obtain a solution with a nominal concentration of about 50 μg/mL of piroxicam.

Sample solution: Add 340 mg of Cream to 4 mL of chloroform and 150 mL of Diluent. Shake the mixture on a wrist action shaker for 15 min, and dilute with Diluent to 200 mL. Pass the solution through a filter of 0.45-μm pore size, and discard the first 5 mL of the filtrate.

Blank: Add 340 mg of Purified Water to 4 mL of chloroform and 150 mL of Diluent. Shake the mixture on a wrist action shaker for 15 min, and dilute with Diluent to 200 mL. Pass the solution through a filter of 0.45-μm pore size, and discard the first 5 mL of the filtrate.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Columns

Guard: 4.6-mm × 2-cm; packing L1

Analytical: 4.6-mm × 30-cm; 10-μm packing L1

Flow rate: 1.0 mL/min

Injection volume: 20 μL

System suitability

Sample: Standard solution

[Note - The retention time for piroxicam is about 7 min.]

Suitability requirements

Relative standard deviation: NMT 2.8% for replicate injections

Analysis

Samples: Standard solution, Sample solution, and Blank

Calculate the percentage of the labeled amount of piroxicam (C₁₅H₁₃N₃O₄S) in the portion of Cream 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 (μg/mL)

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

Acceptance criteria: 90.0%–110.0%

3 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in a tight, light-resistant, plastic resealable container. Store at controlled room temperature.

Beyond-Use Date: NMT 90 days after the date on which it was compounded when stored at controlled room temperature

Labeling: Label it to state the Beyond-Use Date.

USP Reference Standards 〈11〉

USP Piroxicam RS