Acetyldigoxin

(β-Acetyldigoxin, Ph Eur monograph 2168)

C₄₃H₆₆O₁₅    823     5355-48-6

Cardiac Glycoside.

Ph Eur

3β-[(4-O-Acetyl-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)- 2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-12β,14-dihydroxy-5β-card-20(22)-enolide.

97.0 per cent to 102.0 per cent (dried substance).

White or almost white powder.

Practically insoluble in water, sparingly soluble in methylene chloride, slightly soluble in ethanol (96 per cent).

Infrared absorption spectrophotometry (2.2.24).

Comparison    β-acetyldigoxin CRS.

+ 26.2 to + 28.2 (dried substance).

Dissolve 0.50 g in a mixture of equal volumes of methanol R and methylene chloride R and dilute to 25.0 mL with the same mixture of solvents.

Liquid chromatography (2.2.29). Prepare the solutions immediately before use.

Solvent mixture    Mix equal volumes of methanol R2 and acetonitrile for chromatography R.

Test solution    Dissolve 50.0 mg of the substance to be examined in the solvent mixture and dilute to 100.0 mL with the solvent mixture.

Reference solution (a)    Dissolve 10.0 mg of β-acetyldigoxin CRS in the solvent mixture and dilute to 20.0 mL with the solvent mixture.

Reference solution (b)    Dilute 1.0 mL of the test solution to 20.0 mL with the solvent mixture. Dilute 1.0 mL of this solution to 10.0 mL with the solvent mixture.

Reference solution (c)    Dissolve 5 mg of gitoxin CRS (impurity D) in the solvent mixture and dilute to 100.0 mL with the solvent mixture. To 5.0 mL of this solution, add 0.5 mL of reference solution (a) and dilute to 100.0 mL with the solvent mixture.

Reference solution (d)    Dissolve 5.0 mg of β-acetyldigoxin for peak identification CRS (containing impurities A and B) in 10.0 mL of the solvent mixture.

• — size: l = 0.125 m, Ø = 4.0 mm;

• — stationary phase: octadecylsilyl silica gel for chromatography R (4 µm).

• — mobile phase A: water for chromatography R;

• — mobile phase B: acetonitrile for chromatography R;

Flow rate    1.5 mL/min.

Detection    Spectrophotometer at 225 nm.

Injection    10 µL of the test solution and reference solutions (b), (c) and (d).

Identification of impurities    Use the chromatograms obtained with reference solutions (c) and (d) to identify the peaks due to impurities A, B and D.

Relative retention    With reference to β-acetyldigoxin (retention time = about 9 min): impurity B = about 0.3; impurity A = about 0.7; impurity D = about 1.2.

System suitability    Reference solution (c):

• — resolution: minimum 1.5 between the peaks due to β-acetyldigoxin and impurity D;

• — symmetry factor: maximum 2.5 for the peak due to β-acetyldigoxin.

• — impurities A, B: for each impurity, not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.5 per cent);

• — impurity D: not more than 0.6 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.3 per cent);

• — any other impurity: for each impurity, not more than 0.4 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.2 per cent);

• — sum of impurities other than A, B and D: not more than 1.2 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.6 per cent);

• — total: not more than 3 times the area of the principal peak in the chromatogram obtained with reference solution (b) (1.5 per cent);

• — disregard limit: 0.1 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.05 per cent).

The thresholds indicated under Related substances (Table 2034.-1) in the general monograph Substances for pharmaceutical use (2034) do not apply.

Maximum 1.5 per cent, determined on 1.000 g by drying in an oven at 105 °C.

Maximum 0.1 per cent, determined on the residue obtained in the test for loss on drying.

Liquid chromatography (2.2.29) as described in the test for related substances with the following modification.

Injection    Test solution and reference solution (a).

Calculate the percentage content of C₄₃H₆₆O₁₅ from the declared content of β-acetyldigoxin CRS.

Protected from light.

Specified impurities    A, B, D.

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. 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): C, E, F, G, H.

A. 3β-[(3-O-acetyl-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-12β,14-dihydroxy-5β-card-20(22)-enolide (α-acetyldigoxin),

B. 3β-[(2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-12β,14-dihydroxy-5β-card-20(22)-enolide (digoxin),

C. 3β,12β,14-trihydroxy-5β-card-20(22)-enolide (digoxigenin),

D. 3β-[(2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-14,16β-dihydroxy-5β-card-20(22)-enolide (gitoxin),

E. 3β-[(2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-14-hydroxy-5β-card-20(22)-enolide (digitoxin),

F. 3β-[(3,4-O-diacetyl-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-12β,14-dihydroxy-5β-card-20(22)-enolide (diacetyldigoxin),

G. 3β-[(3-O-acetyl-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-14-hydroxy-5β-card-20(22)-enolide (α-acetyldigitoxin),

H. 3β-[(4-O-acetyl-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-d-ribo-hexopyranosyl)oxy]-14-hydroxy-5β-card-20(22)-enolide (β-acetyldigitoxin).

Ph Eur