Standard solutions
Dissolve an accurately weighed quantity of
USP Clozapine RS in chloroform, and mix to obtain a solution having a known concentration of 0.1 mg per mL. Quantitatively dilute portions of this solution with chloroform to obtain the following solutions.
Standard
solution |
Dilution |
Concentration (µg of RS per mL) |
Percentage (%, for comparison with test specimen) |
A |
3 in 10 |
30 |
0.3 |
B |
1 in 5 |
20 |
0.2 |
C |
1 in 10 |
10 |
0.1 |
D |
1 in 20 |
5 |
0.05 |
Procedure
Proceed as directed for
Thin-Layer Chromatography under
Chromatography 621. Examine the plate under short-wavelength UV light, and compare the intensities of any secondary spots observed in the chromatogram of the
Test solution with those of the principal spots in the chromatograms of the
Standard solutions: no spot from the chromatogram of the
Test solution with an
RF value of about 0.82, corresponding to 1,4-bis(8-chloro-5
H-dibenzo[
b,e][1,4]diazepin-11-yl)piperazine; about 0.67, corresponding to 8-chloro-5,10-dihydro-11
H-dibenzo[
b,e][1,4]diazepin-11-one; or about 0.10, corresponding to 8-chloro-11-(1-piperazinyl)-5
H-dibenzo[
b,e][1,4]diazepine, is larger or more intense than that obtained from
Standard solution B, Standard solution C, or
Standard solution A, respectively; no other secondary spot from the chromatogram of the
Test solution is larger or more intense than the principal spot obtained from
Standard solution C (0.1%); and the sum of the intensities of all secondary spots obtained from the
Test solution corresponds to not more than 0.6%.