Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Androgen.
DEFINITION
Testosterone Implants are sterile cylinders prepared by the fusion or heavy compression of Testosterone without the addition of any other substance.
The implants comply with the requirements stated under Parenteral Preparations and with the following requirements.
Content of testosterone, C19H28O2
97 to 103%, calculated with reference to the dried substance, and 90 to 110% of the stated amount.
Diameter
Implants containing less than 50 mg, 2.0 to 2.5 mm; implants containing 50 mg or more, 4.25 to 4.75 mm.
Where appropriate, powder the implants before carrying out the following tests.
IDENTIFICATION
A. The infrared absorption spectrum, Appendix II A, is concordant with the reference spectrum of testosterone (RS 329).
B. Comply with the test for identification of steroids, Appendix III A, using impregnating solvent II and mobile phase D.
C. To 0.1 g in a stoppered tube add 3 mL of anhydrous pyridine and 0.6 mL of acetic anhydride. Heat on a waterbath for 3 hours, add water dropwise until crystals begin to form, then add slowly a further 15 mL of water and allow to stand until precipitation is complete. Filter the precipitate using a sintered-glass crucible and wash with water until the washings are neutral to methyl red solution. Recrystallise from ethanol (96%), adding a few drops of water if necessary to aid crystallisation, and dry at 105°. The melting point of the crystals is about 140°, Appendix V A.
TESTS
Melting point
152° to 156°, Appendix V A.
Specific optical rotation
In a 1% w/v solution in absolute ethanol, +106 to +112, Appendix V F, calculated with reference to the dried substance.
Carbonisation
1% w/v solution in ethanol (96%) is clear, Appendix IV A, and colourless, Appendix IV B, Method I.
Loss on drying
When dried to constant weight at 105°, lose not more than 1.0% of their weight. Use 1 g.
Sulfated ash
Not more than 0.1%, Appendix IX A.
ASSAY
Weigh and powder a single implant. Dissolve 10 mg of the powdered implant in sufficient absolute ethanol to produce 100 mL, dilute 5 mL to 50 mL with absolute ethanol and measure the absorbance of the resulting solution at the maximum at 240 nm, Appendix II B. Calculate the content of C19H28O2 taking 560 as the value of A(1%, 1 cm) at the maximum at 240 nm.
STORAGE
Testosterone Implants should be protected from light.
