Dibucaine Hydrochloride Injection

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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Dibucaine Hydrochloride Injection is a sterile solution of Dibucaine Hydrochloride in Water for Injection. It contains not less than 95.0 percent and not more than 105.0 percent of the labeled amount of dibucaine hydrochloride (C₂₀H₂₉N₃O₂ · HCl).

1 Packaging and storage

Preserve in single-dose or multiple-dose containers, preferably of Type I glass, and protect from light.

2 USP Reference standards 〈11〉

USP Dibucaine Hydrochloride RS

3 Identification

A: 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.

B: Place a volume of Injection, equivalent to about 30 mg of dibucaine hydrochloride, in a suitable evaporating dish, and concentrate on a steam bath to a volume of about 10 mL. Transfer the solution to a separator, render distinctly alkaline with 1 N sodium hydroxide, and extract with four 20-mL portions of ether. Wash the combined ether extracts with 5 mL of water, discarding the washing. Evaporate the ether extracts with the aid of a current of air to dryness, and dry the residue over phosphorus pentoxide for 3 hours: the dibucaine so obtained melts between 62° and 65°.

Bacterial Endotoxins Test 〈85〉-It contains not more than 35.7 USP Endotoxin Units per mg of dibucaine hydrochloride.

pH 〈791〉: between 4.5 and 7.0.

Particulate Matter in Injections 〈788〉: meets the requirements for small-volume injections.

4 Other requirements

It meets the requirements under Injections and Implanted Drug Products 〈1〉.

5 Assay

Mobile phase and Chromatographic system-Proceed as directed in the Assay under Dibucaine.

Standard preparation-Transfer about 50 mg of USP Dibucaine Hydrochloride RS, accurately weighed, to a 100-mL volumetric flask, add an accurately measured volume of water, equivalent to the volume of Injection taken to prepare the Assay preparation, dilute with methanol to volume, and mix. Where the Assay preparation is prepared in a 50-mL volumetric flask, transfer about 25 mg of USP Dibucaine Hydrochloride RS, accurately weighed, to a 100-mL volumetric flask, add an accurately measured volume of water, equivalent to twice the volume of Injection taken to prepare the Assay preparation, dilute with methanol to volume, and mix. Pass through a suitable filter having a 0.5-µm or finer porosity.

Assay preparation-Transfer an accurately measured volume of Injection, equivalent to about 50 mg of dibucaine, to a 100-mL volumetric flask. Dilute with methanol to volume, and mix. Where the Injection is labeled to contain 1 mg or less of dibucaine hydrochloride per mL, transfer an accurately measured volume of Injection, equivalent to about 13 mg of dibucaine hydrochloride, to a 50-mL volumetric flask, dilute with methanol to volume, and mix. Pass through a suitable filter having a 0.5-µm or finer porosity.

Procedure-Separately inject equal volumes (about 10 µL, or 20 µL where the concentration of dibucaine hydrochloride is about 0.25 mg per mL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the area responses for the major peaks. Calculate the quantity, in mg, of dibucaine hydrochloride (C₂₀H₂₉N₃O₂ · HCl) in each mL of the Injection taken by the formula:

C(v/V)(r_u/r_s)

in which C is the concentration, in mg per mL, of USP Dibucaine Hydrochloride RS in the Standard preparation; v is the volume, in mL, of the Assay preparation; V is the volume, in mL, of Injection taken; and r_u and r_s are the area responses of the dibucaine peaks obtained from the Assay preparation and the Standard preparation, respectively.