» Methotrimeprazine Injection is a sterile solution of Methotrimeprazine in Water for Injection, prepared with the aid of hydrochloric acid. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of methotrimeprazine (C19H24N2OS), as the hydrochloride.
Packaging and storage Preserve in single-dose or in multiple-dose containers, preferably of Type I glass, protected from light.
USP Reference standards 11
USP Endotoxin RS
[noteThroughout the following procedures, protect test or assay specimens, the Reference Standard, and solutions containing them, by conducting the procedures without delay, under subdued light, or using low-actinic glassware. ]
Identification Place 1 mL of Injection in a 125-mL separator, and add 1 N sodium hydroxide dropwise until the solution becomes opaque white. Extract with 50 mL of ether, wash the ether extract with 25 mL of water, and discard the washing. Filter the ether extract through a layer of anhydrous sodium sulfate into a beaker, evaporate the filtrate by means of a stream of nitrogen to complete dryness, and dry at 100 for 3 hours: the methotrimeprazine so obtained responds to Identification test A under Methotrimeprazine.
Bacterial endotoxins 85 It contains not more than 17.9 USP Endotoxin Units per mg of methotrimeprazine.
pH 791: between 3.0 and 5.0.
Other requirements It meets the requirements under Injections 1.
20% Phosphoric acid Transfer 23.5 mL of 85% phosphoric acid into a 100-mL volumetric flask containing water, and dilute with water to volume.
Mobile phase Prepare a filtered and degassed mixture of water, acetonitrile, 20% Phosphoric acid, and triethylamine by using the following procedure. Add 20 mL of 20% Phosphoric acid to 450 mL of water, to this solution add 5 mL of triethylamine, and adjust with 1 N sodium hydroxide to a pH of 3.0. Add 500 mL of acetonitrile, and dilute with water to 1000 mL. Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation Dissolve an accurately weighed quantity of USP Methotrimeprazine RS in Mobile phase, and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 0.1 mg per mL.
System suitability preparation Dissolve or add suitable quantities of 1% benzyl alcohol in Mobile phase and USP Methotrimeprazine RS in Mobile phase to obtain a solution containing about 2.0 and 0.1 mg per mL, respectively.
Assay preparation Transfer an accurately measured amount of Injection, equivalent to about 20 mg of methotrimeprazine, accurately weighed, to a 200-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 25-cm column that contains packing L7. The flow rate is about 1 mL per minute. Chromatograph the System suitability preparation, and record the peak responses as directed for Procedure: the resolution, R, between benzyl alcohol and methotrimeprazine is not less than 4.0; and the tailing factor is not more than 1.2. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 1.5%.
Procedure Separately inject equal volumes (about 20 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 methotrimeprazine (C19H24N2OS) in the portion of Injection taken by the formula:
200C(rU/rS)in which C is the concentration, in mg per mL, of USP Methotrimeprazine RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3858Pharmacopeial Forum: Volume No. 28(6) Page 1822