Action and use
Beta-adrenoceptor antagonist.
Definition
Pindolol Tablets contain Pindolol.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of pindolol, C14H20N2O2
90.0 to 110.0% of the stated amount.
Identification
A. Shake a quantity of the powdered tablets containing 50 mg of Pindolol with 80 mL of
ether for 30 minutes, filter and dry the extract with
anhydrous sodium sulfate. Filter the dried extract, remove the ether using a rotary evaporator and dry the residue over
phosphorus pentoxide at 110° at a pressure not exceeding 2 kPa for 1 hour. The
infrared absorption spectrum of the dried residue,
Appendix II A, is concordant with the
reference spectrum of pindolol (
RS 275).
B. The
light absorption,
Appendix II B, in the range 230 to 350 nm of the final solution obtained in the Assay exhibits two maxima, at 264 nm and 287 nm.
C. Shake a quantity of the powdered tablets containing 20 mg of Pindolol with 5 mL of a mixture of 1 volume of
glacial acetic acid and 99 volumes of
methanol for 45 minutes. Centrifuge and dilute 1 mL of the supernatant liquid to 50 mL with the acetic acid-methanol mixture. To 2 mL of this solution add 1 mL of
dimethylaminobenzaldehyde solution R7. A violet-blue colour is produced.
TESTS
Related substances
Carry out the following procedure as rapidly as possible protected from light. Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.
(1) Shake a quantity of the powdered tablets containing 20 mg of Pindolol with 5 mL of a mixture of 1 volume of
glacial acetic acid and 99 volumes of
methanol for 15 minutes, centrifuge and use the supernatant liquid; apply to the plate as the last solution.
(2) Dilute 1 volume of solution (1) to 10 volumes with the acetic acid-methanol mixture and further dilute 7 volumes of this solution to 100 volumes with the same solvent mixture.
(3) Dilute 1 volume of solution (1) to 10 volumes with the acetic acid-methanol mixture and further dilute 3 volumes of this solution to 100 volumes with the same solvent mixture.
chromatographic conditions
(b) Use the mobile phase as described below.
(c) Apply 10 µL of each solution.
(d) Develop the chromatograms without delay. Develop the plate to 10 cm.
mobile phase
4 volumes of 13.5m ammonia, 50 volumes of ethyl acetate and 50 volumes of methanol.
limits
Any spot with an Rf value of about 0.1 in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (0.7%).
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) (0.3%).
Disregard any spot remaining on the line of application.
Assay
Shake a quantity of whole tablets containing 90 mg of Pindolol with 90 mL of methanol for 45 minutes. Centrifuge and dilute 15 mL of the supernatant liquid to 100 mL with methanol. Dilute 5 mL of this solution to 50 mL with methanol and measure the absorbance of the resulting solution at the maximum at 264 nm, Appendix II B. Calculate the content of C14H20N2O2 taking 338 as the value of A (1%, 1 cm) at the maximum at 264 nm. Make no allowance for the fact that fewer than 20 tablets may have been taken.
Storage
Pindolol Tablets should be protected from light.