Action and use
Monoamine reuptake inhibitor; tricyclic antidepressant.
Definition
Amitriptyline Tablets contain Amitriptyline Hydrochloride. They are coated.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of amitriptyline hydrochloride, C20H23N,HCl
90.0 to 110.0% of the stated amount.
Identification
B. Triturate a quantity of the powdered tablets containing 0.1 g of Amitriptyline Hydrochloride with 10 mL of
chloroform, filter and evaporate the filtrate to a low volume. Add
ether until a turbidity is produced and allow to stand. Dissolve 50 mg of the precipitate in 3 mL of
water and add 0.05 mL of a 2.5% w/v solution of
quinhydrone in
methanol. No red colour is produced within 15 minutes (distinction from nortriptyline).
Tests
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions, protected from light.
(1) Extract a quantity of the powdered tablets containing 20 mg of Amitriptyline Hydrochloride with 5 mL of a mixture of 1 volume of
2m hydrochloric acid and 9 volumes of
ethanol (96%), centrifuge and use the supernatant liquid.
(3) 0.0040% w/v of cyclobenzaprine hydrochloride BPCRS.
chromatographic conditions
(b) Use the mobile phase as described below.
(c) Apply 10 µL of each solution.
(d) Develop the plate to 14 cm.
(e) After removal of the plate, dry in air, spray with a freshly prepared mixture of 4 volumes of
formaldehyde and 96 volumes of
sulfuric acid, heat at 100° to 105° for 10 minutes.
mobile phase
3 volumes of diethylamine, 15 volumes of ethyl acetate and 85 volumes of cyclohexane.
limits
Examine the plate under ultraviolet light (365 nm):
any spot corresponding to dibenzosuberone in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (0.25%).
Examine the plate under ultraviolet light (254 nm):
any other secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (3) (1%).
Assay
Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1)
For film-coated tablets Add 50 mL of
0.1m hydrochloric acid to 20 tablets, shake vigorously until the tablets are completely disintegrated, add 100 mL of
methanol and shake for 30 minutes. Dilute the suspension to 200 mL with
methanol, centrifuge and dilute a volume of the supernatant liquid containing 25 mg of Amitriptyline Hydrochloride to 100 mL with
methanol (50%).
For sugar-coated tablets Shake a quantity of the powder containing 50 mg of Amitriptyline Hydrochloride with 50 mL of
0.1m hydrochloric acid for 30 minutes, add 100 mL of
methanol and shake for 30 minutes. Dilute the suspension to 200 mL with
water, centrifuge and use the supernatant liquid.
chromatographic conditions
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 2 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 239 nm.
(f) Inject 20 µL of each solution.
mobile phase
0.03m sodium hexanesulfonate in a mixture of equal volumes of water and acetonitrile, adjusted to pH 4.5 by the addition of glacial acetic acid,
determination of content
Calculate the content of C20H23N,HCl using the declared content of C20H23N,HCl in amitriptyline hydrochloride BPCRS.