(am'' oh bar' bi tal soe' dee um).
2,4,6(1H,3H,5H)-Pyrimidinetrione, 5-ethyl-5-(3-methylbutyl)-, monosodium salt.
Sodium 5-ethyl-5-isopentylbarbiturate [64-43-7].
» Amobarbital Sodium contains not less than 98.5 percent and not more than 100.5 percent of C11H17N2NaO3, calculated on the dried basis.
Packaging and storage Preserve in tight containers.
Labeling Where it is intended for use in preparing injectable dosage forms, the label states that it is sterile or must be subjected to further processing during the preparation of injectable dosage forms.
USP Reference standards 11
USP Endotoxin RS
Completeness of solution 641 Mix 1.0 g with 10 mL of carbon dioxide-free water: after 1 minute, the solution is clear and free from undissolved solid.
A: Infrared Absorption 197K: of residue obtained in the Assay.
B: Ignite about 200 mg: the residue effervesces with acid and responds to the tests for Sodium 191.
Loss on drying 731 Dry about 1 g, accurately weighed, at 105 for 4 hours: it loses not more than 2.0% of its weight.
Heavy metals, Method II 231: 0.003%.
Other requirements Where the label states that Amobarbital Sodium is sterile, it meets the requirements for Sterility and Bacterial endotoxins under Amobarbital Sodium for Injection. Where the label states that Amobarbital Sodium must be subjected to further processing during the preparation of injectable dosage forms, it meets the requirements for Bacterial endotoxins under Amobarbital Sodium for Injection.
Assay Dissolve about 500 mg of Amobarbital Sodium, accurately weighed, in about 15 mL of water in a separator. To the solution add 2 mL of hydrochloric acid, shake, and completely extract the liberated amobarbital with 25-mL portions of chloroform. Test for completeness of extraction by extracting with an additional 10-mL portion of chloroform and evaporating the solvent: not more than 0.5 mg of residue remains. Filter the combined extract through a glass filter funnel into a tared beaker, and wash the separator and the filter with several small portions of chloroform. Evaporate the combined filtrate and washings on a steam bath with the aid of a current of air, dry the residue at 105 for 30 minutes, cool, and weigh. The weight of the residue, multiplied by 1.097, represents the weight of C11H17N2NaO3.
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USP35NF30 Page 2192Pharmacopeial Forum: Volume No. 29(6) Page 1845