Action and use
Monoamine reuptake inhibitor; tricyclic antidepressant.
Definition
Nortriptyline Tablets contain Nortriptyline Hydrochloride. They are coated.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of nortriptyline, C19H21N
90.0 to 110.0% of the stated amount.
Identification
B. Triturate a quantity of the powdered tablets containing the equivalent of 0.1 g of nortriptyline 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 warm
water, cool and add 0.05 mL of a 2.5% w/v solution of
quinhydrone in
methanol. A red colour develops (distinction from amitriptyline).
Tests
Dibenzosuberone
Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.
(1) Extract a quantity of the powdered tablets containing the equivalent of 20 mg of nortriptyline 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.
chromatographic conditions
(b) Use the mobile phase as described below.
(c) Apply 5 µL of each solution.
(d) Develop the plate to 12 cm.
(e) After removal of the plate, dry in air until the solvent has evaporated, spray with
sulfuric acid containing 4% v/v of
formaldehyde solution and examine immediately under
ultraviolet light (
365 nm).
mobile phase
3 volumes of diethylamine, 15 volumes of ethyl acetate and 85 volumes of cyclohexane.
limits
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%).
Assay
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Add 50 mL of
water to 20 tablets, shake vigorously until the tablets have completely disintegrated, add 100 mL of
methanol and shake for 30 minutes. Add sufficient
water to produce 200 mL, filter and dilute a volume of the filtrate containing the equivalent of 25 mg of nortriptyline to 100 mL with
methanol (
50%).
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
0.56% w/v solution of sodium hexanesulfonate in a mixture of equal volumes of water and acetonitrile adjusted to pH 4.5 with glacial acetic acid.
determination of content
Calculate the content of C19H21N using the declared content of C19H21N in nortriptyline hydrochloride BPCRS.
Labelling
The quantity of active ingredient is stated in terms of the equivalent amount of nortriptyline.