Primidone
;)
4,6(1H,5H)-Pyrimidinedione,5-ethyldihydro-5-phenyl-.
5-Ethyldihydro-5-phenyl-4,6(1H,5H)-pyrimidinedione [125-33-7].
»Primidone contains not less than 98.0percent and not more than 102.0percent of C12H14N2O2,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification—
A:Infrared Absorption á197Kñ—
If a difference appears,dissolve portions of both the tests specimen and the Reference Standard in alcohol,evaporate the solutions to dryness,and repeat the tests.
B:Ultraviolet Absorption á197Uñ—
Solution:
400µg per mL.
Medium:
alcohol.
Absorptivities at 257nm,calculated on the dried basis,do not differ by more than 3.0%.
C:
Fuse 0.20g with 0.20g of anhydrous sodium carbonate:ammonia is evolved.
Loss on drying á731ñ—
Dry it at 105
for 2hours:it loses not more than 0.5%of its weight.
for 2hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ:
not more than 0.2%.
Ordinary impurities á466ñ—
Test solution—
Prepare a solution in methanol having a known concentration of 2mg per mL.
Standard solutions—
Prepare solutions in methanol having known concentrations of 2,10,20,and 40µg per mL.
Eluant:
a mixture of butyl alcohol,glacial acetic acid,and water (5:3:2).
Visualization—
Expose the plate to chlorine gas for about 15minutes,air-dry until the chlorine has dissipated (about 15minutes),and follow with visualization technique 20.
Organic volatile impurities,Method Vá467ñ:
meets the requirements.
Solvent—
Use dimethyl sulfoxide.
Assay—
Transfer about 40mg of Primidone,accurately weighed,to a 100-mLvolumetric flask.Add 70mLof alcohol,and boil gently to dissolve.Cool,and add alcohol to volume.Determine the absorbances in a 2-cm cell,with a suitable spectrophotometer,using alcohol as the blank,at the minima that occur at about 254nm and 261nm and at the maximum that occurs at about 257nm.Concomitantly determine the absorbances of a Standard solution in alcohol of USP Primidone RS,similarly prepared to have a known concentration of about 400µg per mL.Calculate the quantity,in mg,of C12H14N2O2in the Primidone taken by the formula:
0.1C(2A257–A254–A261)U/(2A257–A254–A261)S,
in which Cis the concentration,in µg per mL,of USP Primidone RSin the Standard solution,and the parenthetic expressions are the differences in the absorbances of the two solutions at the wavelengths indicated by the subscripts for the solution of Primidone (U)and the Standard solution (S),respectively.
Auxiliary Information—
Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 1619
Pharmacopeial Forum:Volume No.27(4)Page 2774
Phone Number:1-301-816-8330