Imipenem and Cilastatin for Injectable Suspension
» Imipenem and Cilastatin for Injectable Suspension is a sterile mixture of Imipenem and Cilastatin Sodium. It contains not less than 90.0 percent and not more than 115.0 percent of the labeled amounts of imipenem (C12H17N3O4S) and cilastatin (C16H26N2O5S).
Packaging and storage Preserve in Containers for Sterile Solids as described under Injections 1, and store at controlled room temperature.
Labeling Label it to indicate that the suspension obtained when constituted as directed in the labeling is for intramuscular injection only.
USP Reference standards 11
USP Endotoxin RS
USP Imipenem Monohydrate RS
Identification The retention times of the peaks for imipenem and cilastatin in the chromatogram of Assay preparation 1 correspond to those of the Imipenem standard preparation and the Cilastatin standard preparation as obtained in the Assay.
Bacterial endotoxins 85 It contains not more than 0.23 USP Endotoxin Unit per mg of imipenem and not more than 0.23 USP Endotoxin Unit per mg of cilastatin.
Sterility 71 It meets the requirements when tested as directed for Membrane Filtration under Test for Sterility of the Product to be Examined, the specimen being dissolved in Fluid A.
pH 791: between 6.0 and 7.5, when constituted as directed in the labeling.
Uniformity of dosage units 905: meets the requirements.
Loss on drying 731 Dry about 100 mg in vacuum at a pressure not exceeding 5 mm of mercury at 60 for 3 hours: it loses not more than 3.5% of its weight.
pH 6.8 Buffer, Mobile phase, Imipenem standard preparation, Cilastatin standard preparation, and Chromatographic system Prepare as directed in the Assay under Imipenem and Cilastatin for Injection.
Assay preparation Constitute Imipenem and Cilastatin for Injectable Suspension in a volume of saline TS, accurately measured, corresponding to the volume of solvent specified in the labeling. Withdraw all of the withdrawable contents, using a suitable hypodermic needle and syringe, and dilute quantitatively with saline TS to obtain a stock solution containing about 2500 µg of imipenem per mL. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, dilute with pH 6.8 Buffer to volume, and mix.
Procedure Separately inject equal volumes (about 10 µL) of the Imipenem standard preparation, the Cilastatin standard preparation, and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantities, in mg, of anhydrous imipenem (C12H17N3O4S) and cilastatin (C16H26N2O5S) withdrawn from the container taken by the formula:
(CPL / D)(rU / rS)in which C is the concentration, in mg per mL, of USP Imipenem Monohydrate RS or USP Cilastatin Ammonium Salt RS in the appropriate Standard preparation; P is the content, in µg per mg, of anhydrous imipenem (C12H17N3O4S) or cilastatin (C16H26N2O5S) in the relevant Reference Standard; L is the labeled quantity, in mg, of imipenem or cilastatin in the container; D is the concentration, in µg per mL, of imipenem or cilastatin in the Assay preparation based on the labeled quantity in the container and the extent of dilution; and rU and rS are the peak responses of the corresponding analyte obtained from the Assay preparation and the appropriate Standard preparation, respectively.
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USP35NF30 Page 3482Pharmacopeial Forum: Volume No. 32(6) Page 1698