Pentobarbital Sodium
C11H17N2NaO3
248.25
2,4,6(1H,3H,5H)-Pyrimidinetrione, 5-ethyl-5-(1-methylbutyl)-, monosodium salt. Sodium 5-ethyl-5-(1-methylbutyl)barbiturate [57-33-0]. » Pentobarbital Sodium contains not less than 98.0 percent and not more than 102.0 percent of C11H17N2NaO3, calculated on the dried basis. Where the material is labeled as intended solely for veterinary use, Pentobarbital Sodium contains not less than 97.0 percent and not more than 102.0 percent of C11H17N2NaO3, calculated on the dried basis.
Packaging and storage
Preserve in tight containers.
Completeness of solution
Mix 1.0 g with 10 mL of carbon dioxide-free water: after 1 minute, the solution is clear and free from undissolved solid.
Identification
A:
Ultraviolet Absorption 197U
Solution:
10 µg per mL.
Medium:
dilute ammonium hydroxide (1 in 200).
B:
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
C:
Ignite about 200 mg: the residue effervesces with acids, and meets the requirements of the tests for Sodium 191.
pH 791:
between 9.8 and 11.0, in the solution prepared in the test for Completeness of solution.
Loss on drying 731
Dry it at 105 for 6 hours: it loses not more than 3.5% of its weight.
Heavy metals, Method II 231:
0.003%.
Related compounds
Mobile phase
Prepare as directed in the Assay.
Standard solution
Dissolve an accurately weighed quantity of USP Pentobarbital RS in Mobile phase, and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 0.001 mg per mL.
Test solution
Transfer about 110 mg of Pentobarbital Sodium, accurately weighed, to a 100-mL volumetric flask, add about 80 mL of Mobile phase, and sonicate until dissolved. Dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)
The liquid chromatograph is equipped with a 214-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L1. The flow rate is about 1.0 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the capacity factor, k¢, is not less than 2.5; the column efficiency is not less than 15,000 theoretical plates; the tailing factor is not more than 1.5; and the relative standard deviation for replicate injections is not more than 15.0%.
Procedure
Separately inject equal volumes (about 10 µL) of the Standard solution and Test solution into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the percentage of any impurity in the portion of Pentobarbital Sodium taken by the formula:
(248.25/226.27)(10,000/F)(C/W)(ri / rS)
in which 248.25 and 226.27 are the molecular weights of pentobarbital sodium and pentobarbital, respectively; F is the relative response factor of the impurity according to the table below; C is the concentration, in mg per mL, of USP Pentobarbital RS in the Standard solution; W is the weight, in mg, of Pentobarbital Sodium, on the dried basis, used to prepare the Test solution; ri is the peak area for any impurity in the Test solution; and rS is the peak area for pentobarbital in the Standard solution: the impurities meet the requirements given in the table below:
Assay
[noteUse the value for Loss on drying obtained at the same time as the preparation of the Test solution in the test for Related compounds and the Assay preparation in the Assay.]
Mobile phase, Standard preparation, and Chromatographic system
Proceed as described in the Assay under Pentobarbital.
Assay preparation
Transfer about 110 mg of Pentobarbital Sodium, accurately weighed, to a 100-mL volumetric flask, add about 80 mL of Mobile phase, and sonicate until dissolved. Dilute with Mobile phase to volume, and mix. Transfer 10.0 mL of this solution to a 100-mL volumetric flask. Dilute with Mobile phase to volume, and mix.
Procedure
Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C11H17N2NaO3 in the portion of Pentobarbital Sodium taken by the formula:
(248.25/226.27)1000C(rU / rS)
in which 248.25 and 226.27 are the molecular weights of pentobarbital sodium and pentobarbital, respectively; C is the concentration, in mg per mL, of USP Pentobarbital RS in the Standard preparation; and rU and rS are the peak areas obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
Chromatographic Column
USP32NF27 Page 3250
Pharmacopeial Forum: Volume No. 31(1) Page 73
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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