Prednicarbate Ointment

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

Prednicarbate Ointment contains NLT 90.0% and NMT 110.0% of the labeled amount of prednicarbate (C₂₇H₃₆O₈) in a suitable ointment base.

2 IDENTIFICATION

A. The retention time of the prednicarbate peak in the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 Procedure

Solution A: 0.01 M monobasic potassium phosphate

Solution B: Acetonitrile and dehydrated alcohol (2:1)

Mobile phase: See Table 1.

Table 1

Standard stock solution: 0.3 mg/mL USP Prednicarbate RS in dehydrated alcohol

Standard solution: 30 µg/mL of USP Prednicarbate RS prepared as follows. Transfer 10.0 mL of the Standard stock solution to a 100-mL volumetric flask. Add 15 mL of tetrahydrofuran and 30 mL of Solution B, and dilute with Solution A to volume.

System suitability stock solution 1: 0.3 mg/mL each of USP Prednicarbate Related Compound B RS and USP Prednicarbate Related Compound C RS in dehydrated alcohol

System suitability stock solution 2: Transfer 15 mg of USP Prednicarbate Related Compound A RS to a 50-mL volumetric flask. Add 1.0 mL of System suitability stock solution 1, and dilute with dehydrated alcohol to volume.

System suitability solution: Transfer 10.0 mL of the Standard solution to a volumetric flask. Add 1.0 mL of System suitability stock solution 2, 1 mL of tetrahydrofuran, and 2 mL of acetonitrile. Dilute with Solution A to 20.0 mL.

Sample solution: Transfer the equivalent of 3.0 mg of prednicarbate from a quantity of Ointment to a 100-mL volumetric flask. Add 15 mL of tetrahydrofuran, shake vigorously, and allow to stand in an ultrasonic bath until the sample has dissolved. Add 20 mL of dehydrated alcohol, and shake vigorously. Add 20 mL of acetonitrile, and shake vigorously. Immediately dilute with Solution A to volume, and shake vigorously. Allow to stand in an ice bath for at least 15 min. Shake vigorously, and pass through a folded paper filter. Pass the filtrate through a membrane filter of 0.45-µm pore size. 

Prednicarbate-Ointment-USP-TTT

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 243 nm

Column: 4.0-mm × 25-cm; 5-µm packing L1

Column temperature: 40°

Flow rate: 1 mL/min

Injection volume: 60 µL

System suitability

Samples: Standard solution and System suitability solution

Suitability requirements

Resolution: NLT 1.5 between prednicarbate and prednicarbate related compound A, System suitability solution

Tailing factor: 0.7–1.5, Standard solution

Relative standard deviation: NMT 2.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of prednicarbate (C₂₇H₃₆O₈) in the portion of Ointment 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 Prednicarbate RS in the Standard solution (mg/mL)

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

Acceptance criteria: 90.0%–110.0% 

4 IMPURITIES

4.1 Organic Impurities

Solution A, Solution B, System suitability stock solution 1, System suitability stock solution 2, Mobile phase, Standard stock solution, Standard solution, System suitability solution, Sample solution, and Chromatographic system: Proceed as directed in the Assay.

Sensitivity solution: 0.03 µg/mL of USP Prednicarbate RS prepared as follows. Dilute 1.0 mL of the Standard solution with dehydrated alcohol to 50.0 mL. Dilute 1.0 mL of the resulting solution with Solution A to 20.0 mL.

System suitability

Samples: Standard solution, System suitability solution, Sensitivity solution

Suitability requirements

Resolution: NLT 1.5 between prednicarbate and prednicarbate related compound A, System suitability solution

Tailing factor: 0.7–1.5, Standard solution

Relative standard deviation: NMT 2.0%, Standard solution

Signal-to-noise ratio: NLT 3, Sensitivity solution

Analysis

Sample: Sample solution

Calculate the percentage of each related compound and unknown impurity in the portion of Ointment taken:

Result = (r_U/r_T) × 100

r_U = peak response for each impurity

r_T = sum of all the peak responses

Acceptance criteria: See Table 2. 

Table 2

5 PERFORMANCE TESTS

Minimum Fill: Meets the requirements

6 SPECIFIC TESTS

Consistency: At room temperature, a string of Ointment having a length of 2 cm retains its shape on a glass plate for at least 10 min. It can be spread easily and has no visible lumps.

Microbial Enumeration Tests 〈61〉 and Tests for Specified Microorganisms 〈62〉: It meets the requirements of the tests for the absence of Staphylococcus aureus and Pseudomonas aeruginosa. The total aerobic bacterial count does not exceed 10² cfu/g.

7 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers, and store at controlled room temperature.

USP Reference Standards 〈11〉

USP Prednicarbate RS

USP Prednicarbate Related Compound A RS

1,2-Dihydroprednicarbate.

USP Prednicarbate Related Compound B RS

Prednisolone-17-ethylcarbonate.

USP Prednicarbate Related Compound C RS

Prednisolone-21-propionate.