(Ph. Eur. monograph 1614)
C23H32O3 356.5 979-32-8
Action and use
Estrogen.
DEFINITION
3-Hydroxyestra-1,3,5(10)-trien-17β-yl pentanoate.
Content
97.5 per cent to 102.0 per cent (dried substance).
CHARACTERS
Appearance
White or almost white, crystalline powder or colourless crystals.
Solubility
Practically insoluble in water, freely soluble in methylene chloride, soluble in ethanol (96 per cent).
IDENTIFICATION
A. Infrared absorption spectrophotometry (2.2.24).
Comparison: estradiol valerate CRS.
B. Examine the chromatograms obtained in the assay.
Results: The principal peak in the chromatogram obtained with test solution (b) is similar in retention time and size to the principal peak in the chromatogram obtained with reference solution (c).
TESTS
Solution S
Dissolve 0.500 g in methanol R and dilute to 20.0 mL with the same solvent.
Appearance of solution
Solution S is clear (2.2.1) and colourless (2.2.2, Method II).
Specific optical rotation (2.2.7)
+ 41 to + 47 (dried substance), determined on solution S.
Related substances
Liquid chromatography (2.2.29).
Test solution (a): Dissolve 50.0 mg of the substance to be examined in acetonitrile R1 and dilute to 10.0 mL with the same solvent.
Test solution (b): Dilute 5.0 mL of test solution (a) to 20.0 mL with acetonitrile R1.
Reference solution (a): Dissolve 3 mg of estradiol valerate for system suitability CRS (containing impurities A, C, D and E) in acetonitrile R1 and dilute to 1.0 mL with the same solvent.
Reference solution (b): Dilute 1.0 mL of test solution (a) to 100.0 mL with acetonitrile R1. Dilute 1.0 mL of this solution to 10.0 mL with acetonitrile R1.
Reference solution (c): Dissolve 50.0 mg of estradiol valerate CRS in acetonitrile R1 and dilute to 10.0 mL with the same solvent. Dilute 5.0 mL of the solution to 20.0 mL with acetonitrile R1.
Column:
— size: l = 0.10 m, Ø = 4.6 mm;
— stationary phase: end-capped solid core alkylsilyl silica gel for chromatography R (2.6 μm).
Mobile phase:
— mobile phase A: water R;
— mobile phase B: acetonitrile R1;
| Time
(min) |
Mobile phase A
(per cent V/V) |
Mobile phase B
(per cent |
| 0 – 1 | 48 | 52 |
| 1 – 10 | 48 → 35 | 52 → 65 |
| 10 – 17.5 | 35 → 0 | 65 → 100 |
| 65 → 100 | 0 | 100 |
Flow rate: 2.0 mL/min.
Detection: Spectrophotometer at 220 nm.
Injection: 5 μL of test solution (a) and reference solutions (a) and (b).
Identification of impurities: Use the chromatogram supplied with estradiol valerate for system suitability CRS and the chromatogram obtained with reference solution (a) to identify the peaks due to impurities A, C, D and E.
Relative retention: With reference to estradiol valerate (retention time = about 9 min): impurity A = about 0.1; impurity C = about 0.9; impurity D = about 1.3; impurity E = about 1.7.
System suitability: Reference solution (a):
— resolution: minimum 2.5 between the peaks due to impurity C and estradiol valerate.
Calculation of percentage contents:
— correction factor: multiply the peak area of impurity C by 0.5;
— for each impurity, use the concentration of estradiol valerate in reference solution (b).
Limits:
— impurity D: maximum 0.4 per cent;
— impurities A, C: for each impurity, maximum 0.2 per cent;
— impurity E: maximum 0.15 per cent;
— unspecified impurities: for each impurity, maximum 0.10 per cent;
— total: maximum 0.5 per cent;
— reporting threshold: 0.05 per cent.
Loss on drying (2.2.32)
Maximum 1.0 per cent, determined on 0.500 g by drying in an oven at 105 °C for 3 h.
ASSAY
Liquid chromatography (2.2.29) as described in the test for related substances with the following modification.
Injection: Test solution (b) and reference solution (c).
Calculate the percentage content of C23H32O3 taking into account the assigned content of estradiol valerate CRS.
STORAGE
Protected from light.
IMPURITIES
Specified impurities A, C, D, E.
Other detectable impurities (the following substances would, if present at a sufficient level, be detected by one or other of the tests in the monograph. They are limited by the general acceptance criterion for other/unspecified impurities and/or by the general monograph Substances for pharmaceutical use (2034). It is therefore not necessary to identify these impurities for demonstration of compliance. See also 5.10. Control of impurities in substances for pharmaceutical use) B, F, G, H, I, J.
A. estra-1,3,5(10)-triene-3,17β-diol (estradiol),
B. 17β-hydroxyestra-1,3,5(10)-trien-3-yl pentanoate,
C. 3-hydroxyestra-1,3,5(10),9(11)-tetraen-17β-yl pentanoate,
D. 3-hydroxy-4-methylestra-1,3,5(10)-trien-17β-yl pentanoate,
E. estra-1,3,5(10)-trien-3,17β-diyl dipentanoate,
F. 3-hydroxyestra-1,3,5(10)-trien-17β-yl butanoate,
G. 3-hydroxyestra-1,3,5(10),6-tetraen-17β-yl pentanoate,
H. 3-hydroxy-2-pentanoylestra-1,3,5(10)-trien-17β-yl pentanoate,
I. (1S,3aS,3bR,10aR,10bS,13S,13aS,15aS,18bS,20aS)-13a,17,17,20a-tetramethyl-2,3,3a,3b,4,5,9,10,10a,10b,11,12,13,13a,14,15,15a,17,18b,19,20,20a-docosahydro-1H-bis(cyclopenta[5,6]naphtho)[1,2-b:2ʹ,1ʹ-i]xanthene-1,13-diyl dipentanoate,
J. 3-methoxyestra-1,3,5(10)-trien-17β-yl pentanoate.
