Tadalafil Compounded Oral Suspension

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

Tadalafil Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of tadalafil (C₂₂H₂₉N₃O₄).

Prepare Tadalafil Compounded Oral Suspension 5 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

^a Adcirca 20-mg tablets, Eli Lilly and Company, Indianapolis, IN.

^b Perrigo Pharmaceuticals, Allegan, MI.

Place the required number of tablets in a suitable mortar, and comminute to a fine powder. Wet the powder with a small amount of the Vehicle, and triturate to make a smooth paste. Add increasing volumes of the Vehicle to make a tadalafil liquid that is pourable. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add enough of the Vehicle to bring to final volume, and mix well.

2 ASSAY

2.1 Procedure

Solution A: 10 mM sodium phosphate adjusted with phosphoric acid to a pH of 3.0. Pass through a nylon filter of 0.45-μm pore size.

Solution B: Water adjusted with phosphoric acid to a pH of 3.0

Mobile phase: Acetonitrile and Solution A (60:40)

Diluent: Acetonitrile and Solution B (50:50)

Standard stock solution: 5 mg/mL of tadalafil prepared from USP Tadalafil RS in acetonitrile. Mix well, and store at 2°–8°.

Standard solution: Transfer 2.0 mL of the Standard stock solution into a 500-mL volumetric flask, and dilute with Diluent to volume. Mix well.

Centrifuge an aliquot for 5 min at 14,000 rpm. Protect from light, and store at 2°–8°.

Sample solution: Transfer 2.0 mL of Oral Suspension into a 500-mL volumetric flask, and dilute with Diluent to volume. Mix well. Centrifuge an aliquot for 5 min at 14,000 rpm. Protect from light, and store at 2°–8°.

2.2 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 220 nm

Column: 4.6-mm × 25-cm; 5-μm packing L1

Temperatures

Autosampler: 5°

Column: 30°

Flow rate: 0.8 mL/min

Injection volume: 25 μL

2.3 System suitability

Sample: Standard solution

[Note—The retention time for tadalafil is about 4.5 min.]

2.4 Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% for replicate injections

2.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of tadalafil (C₂₂H₂₉N₃O₄) in the portion of Oral Suspension taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of tadalafil from the Sample solution

r_S = peak response of tadalafil from the Standard solution

C_S = concentration of tadalafil in the Standard solution (mg/mL)

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

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

pH 〈791〉: 4.3–5.3

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in tight, light-resistant containers. Store at 2°–8° or controlled room temperature.

Beyond-Use Date: NMT 90 days after the date on which it was compounded when stored at 2°–8° or controlled room temperature.

Labeling: Label it to indicate that it is to be well-shaken before use, and to state the Beyond-Use Date.

USP Reference Standards 〈11〉

USP Tadalafil RS