ASSAY OF MEPHENTERMINE AND ITS PREPARATIONS

Mephentermine sulfate is assayed by direct titration in glacial acetic acid with perchloric acid titrant and p‐naphtholbenzein indicator. Mephentermine sulfate tablets are assayed by mixing the finely powdered sample with purified siliceous earth and magnesium oxide held in a fritted‐glass filtering funnel, moistening the mixture with water to release the base, eluting the base with warm chloroform, receiving the eluate in glacial acetic acid, and titrating it with perchloric acid using p‐naphtholbenzein indicator. Individual tablets are assayed by receiving the eluate into 10.0 ml. of 0.1 N sulfuric acid, shaking to extract the base from the chloroform, and determining the mephentermine spectrophotometrically using the base‐line correction method proposed by Rotondaro and the assayed tablet mixture as the standard. Mephentermine sulfate injection is assayed by adsorbing the sample into a controlled amount of siliceous earth‐magnesium oxide mixture and proceeding with elution and titration as for the tablets. Loss in drying specifications for mephentermine sulfate are supported by thermo‐ gravimetric data. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company