Calcipotriene

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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C₂₇H₄₀O₃ 412.60 

9,10-Secochola-5,7,10(19),22-tetraene-1,3,24-triol, 24-cyclopropyl-, (1α,3β,5Z,7E,22E,24S)-; 

(5Z,7E,22E,24S)-24-Cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-1α,3β,24-triol CAS RN®: 112965-21-6; UNII: 143NQ3779B. Monohydrate 

C₂₇H₄₀O₃.H₂O 430.63 CAS RN®: 147657-22-5. 

1 DEFINITION 

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Calcipotriene is anhydrous or contains one molecule of water of hydration. The anhydrous form contains NLT 97.0% and NMT 102.0% of calcipotriene (C₂₇H₄₀O₃), calculated on the dried basis. The monohydrate form contains NLT 96.0% and NMT 102.0% of calcipotriene  

(C₂₇H₄₀O₃), calculated on the anhydrous and solvent-free basis.  

2 IDENTIFICATION 

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K 

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

3 ASSAY 

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Procedure 

Protect solutions containing calcipotriene from light and air. Prepare the Standard solution and the Sample solution NMT 1 h before use. Prepare the System suitability solution daily. 

Buffer: 1.0 g/L of tris(hydroxymethyl)aminomethane adjusted with phosphoric acid to a pH of 7.25 ± 0.25 Mobile phase: Acetonitrile and Buffer (45:55) 

System suitability solution: 0.1 mg/mL of USP Calcipotriene RS and 0.01 mg/mL of USP Calcipotriene Related Compound C RS in Mobile phase 

Standard solution: 0.1 mg/mL of USP Calcipotriene RS dissolved in 10% of acetonitrile and then diluted in Mobile phase Sample solution: 0.1 mg/mL of Calcipotriene dissolved in 10% of acetonitrile and then diluted in Mobile phase Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC 

Detector: UV 264 nm 

Column: 4.0-mm × 25-cm; 5-µm packing L7 

Autosampler temperature: 4° 

Flow rate: 1.0 mL/min 

Injection volume: 20 µL 

System suitability 

Samples: System suitability solution and Standard solution  

[Note-The relative retention times for calcipotriene related compound C and calcipotriene are 0.94 and 1.0, respectively.] Suitability requirements 

Resolution: NLT 1.5 between calcipotriene related compound C and calcipotriene, System suitability solution  Relative standard deviation: NMT 1.0%, Standard solution  

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of calcipotriene (C₂₇H₄₀O₃) in the portion of Calcipotriene taken: 

Result = (r_U/r_S) x (C_S/C_U) × 100 

r_U = peak response of calcipotriene from the Sample solution

r_S = peak response of calcipotriene from the Standard solution

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

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

Acceptance criteria 

Labeled as anhydrous form: 97.0%-102.0% on the dried basis 

Labeled as monohydrate form: 96.0%-102.0% on the anhydrous and solvent-free basis  

4 IMPURITIES 

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Organic Impurities, Procedure 1: HPLC 

Protect solutions containing calcipotriene from light and air. Prepare the Standard solution and the Sample solution NMT 1 h before use. Prepare the System suitability solution daily. 

Buffer, Mobile phase, System suitability solution, and Chromatographic system  : Proceed as directed in the Assay. Standard stock solution: Use the Standard solution in the Assay. 

Standard solution: 0.004 mg/mL of USP Calcipotriene RS in Mobile phase, from the Standard stock solution 

Sensitivity solution: 0.2 µg/mL of USP Calcipotriene RS in Mobile phase, from Standard solution  Sample solution: 0.4 mg/mL of Calcipotriene dissolved in 10% of acetonitrile and then diluted in Mobile phase 

System suitability 

Samples: System suitability solution, Standard solution, and Sensitivity solution 

[Note-The relative retention times for calcipotriene related compound C and calcipotriene are 0.94 and 1.0, respectively.] Suitability requirements 

Resolution: NLT 1.5 between calcipotriene related compound C and calcipotriene, System suitability solution 

Relative standard deviation: NMT 5.0%, Standard solution 

Signal-to-noise ratio: NLT 10, Sensitivity solution  

Analysis 

Samples: Standard solution and Sample solution 

Result = (r_U/r_S) x (C_S/C_U) × 100 

r_U = ppeak response of any impurity from the Sample solution

r_S = peak response of calcipotriene from the Standard solution 

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

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

Calculate the percentage of any impurity in the portion of Calcipotriene taken: 

Acceptance criteria: See Table 1. The reporting threshold is 0.05%.  

Table 1 

^a(5Z,7Z,22E,24S)-24-Cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-1α,3β,24-triol.

^b(5E,7E,22E,24S)-24-Cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-1α,3β,24-triol. 

^c(5Z,7E,22E,24R)-24-Cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-1α,3β,24-triol. 

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Organic Impurities, Procedure 2: TLC 

Prepare solutions containing calcipotriene in low-actinic glassware, and protect from air. Carry out the test as rapidly as possible. Diluent: Chloroform and triethylamine (9:1) 

System suitability solution: 10 mg/mL of USP Calcipotriene RS in Diluent. Heat in a water bath at 60° for 2 h to form pre-Calcipotriene.  

Standard solution 1: 0.025 mg/mL of USP Calcipotriene RS in Diluent (0.25%) 

Standard solution 2: 0.01 mg/mL of USP Calcipotriene RS in Diluent (0.10%) 

Standard solution 3: 0.05 mg/mL of USP Calcipotriene RS in Diluent (0.5%)  

Sample solution: 10 mg/mL of Calcipotriene in Diluent 

Developing solvent system: Methylene chloride and isobutyl alcohol (80:20) 

Chromatographic system 

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

Mode: TLC 

Adsorbent: 0.25-mm layer of chromatographic plate coated with silica gel mixture 

Application volume: 10 µL 

Spray reagent: Transfer 20 mL of sulfuric acid into a 100-mL volumetric ask, and dilute with alcohol to volume. 

System suitability 

Sample: System suitability solution 

Suitability requirements 

Resolution: The secondary spot pre-Calcipotriene  and principle spot calcipotriene are clearly separated. Analysis 

Samples: Standard solution 1, Standard solution 2, Standard solution 3,  and Sample solution 

Develop with Developing solvent system until the solvent system has moved two-thirds of the plate from the point of spotting. Remove the plate, and let the plate air-dry. Dry it again at 140° for 10 min followed by spraying the hot plate with the Spray reagent. Dry the plate for NMT 1 min at 140°. Examine the plate under UV light at 366 nm. 

Acceptance criteria: The spot of any impurity in the Sample solution is not more intense than the spot of calcipotriene in the appropriate Standard solution specified in Table 2. 

Table 2 

^a 24,24′-Oxybis[(5Z,7E,22E,24S)-24-cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-1α,3β-diol].

^b (5Z,7E,22E,24R)-24-Cyclopropyl-24-{[(5Z,7E,22E,24S)-24-cyclopropyl-1α,3β-dihydroxy-9,10-secochola-5,7,10(19),22-tetraen-24-yl]oxy}-9,10- secochola-5,7,10(19),22-tetraene-1α,3β-diol. 

^c (5E,6E,22E,24S)-24-Cyclopropyl-9,10-secochola-5(10),6,22-triene-1α,3β,24-triol. 

^d (5Z,7E  ,22E)-24-Cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-24-one-1α,3β-diol. 

5 SPECIFIC TESTS 

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Loss on Drying (where it is labeled as anhydrous form)  

(See Thermal Analysis 〈891〉.) 

Sample: 5 mg 

Analysis: Heat the Sample to 105° at a rate of 10°/min, and hold at 105° for 60 min.  

Acceptance criteria: NMT 1.0% 

Add the following: 

Water Determination 〈921〉, Method I(where it is labeled as monohydrate form): 3.3%-5.0%  

6 ADDITIONAL REQUIREMENTS 

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Packaging and Storage: Preserve in tight containers. If labeled as anhydrous form,  store at 2°-8° or at −20° or below. If labeled as monohydrate, store at room temperature.  Protect from light. 

Add the following: 

Labeling: Label it to indicate whether it is the anhydrous form or the monohydrate form.  

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USP Reference Standards 〈11〉 

USP Calcipotriene RS 

USP Calcipotriene Related Compound C RS 

(5E,7E,22E,24S)-24-Cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-1α,3β,24-triol. 

C₂₇H₄₀O₃ 412.61