Dexmedetomidine 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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1 DEFINITION 

Dexmedetomidine Injection is a sterile solution containing Dexmedetomidine Hydrochloride and sodium chloride, suitable for dilution prior to intravenous administration. It contains NLT 90.0% and NMT 110.0% of the labeled amount of dexmedetomidine free base (C₁₃H₁₆N₂). [Note— This monograph is not applicable to veterinary articles described under 21 CFR 522.558.] 

2 IDENTIFICATION 

A. The retention time of the dexmedetomidine peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay. 

B. The UV absorption spectrum of the major peak of the Sample solution exhibits maxima and minima at the same wavelengths as those of the Standard solution, as obtained in the Assay. 

3 ASSAY

3.1 Procedure 

Buffer: Dissolve 2.4 g of disodium hydrogen phosphate heptahydrate and 0.14 g of monobasic sodium phosphate in 1 L of water. Adjust with 0.1 N phosphoric acid or 0.1 N sodium hydroxide to a pH of 7.8, if needed. 

Mobile phase: Methanol and Buffer (600:400) 

Diluent: 0.9% sodium chloride in water 

Standard solution: 4.8 µg/mL of USP Dexmedetomidine Hydrochloride RS in water 

Sample solution: Nominally equivalent to 4 µg/mL of dexmedetomidine in Diluent 

Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC 

Detector: UV 220 nm. For Identication B, use UV diode array, 200–400 nm. 

Column: 4.6-mm × 15-cm; 5-µm packing L1 

Column temperature: 30° 

Flow rate: 1 mL/min 

Injection volume: 50 µL 

Run time: NLT 1.8 times the retention time of dexmedetomidine 

System suitability 

Sample: Standard solution 

Suitability requirements 

Tailing factor: NMT 2.0 

Relative standard deviation: NMT 2.0% 

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of the labeled amount of dexmedetomidine (C₁₃H₁₆N₂) as free base in the portion of Injection taken: 

Result = (r_u/r_s) x (C_s/C_u) × (M_r1/M_r2) × 100 

r_u = peak response from the Sample solution  

r_s = peak response from the Standard solution 

C_s = concentration of USP Dexmedetomidine Hydrochloride RS in the Standard solution (µg/mL) 

C_u = nominal concentration of dexmedetomidine in the Sample solution (µg/mL) 

M_r1 = molecular weight of dexmedetomidine free base, 200.28 

M_r2 = molecular weight of dexmedetomidine hydrochloride, 236.74 

Acceptance criteria: 90.0%–110.0% 

4 IMPURITIES 

4.1 Organic Impurities 

Buffer and Mobile phase: Proceed as directed in the Assay. 

Butylparaben stock solution: 0.25 mg/mL of butylparaben prepared as follows. To a suitable amount of butylparaben in a suitable volumetric ask, add methanol, 5% of total volume, and dilute with water to volume. 

Butylparaben solution: 0.0025 mg/mL of butylparaben in water from Butylparaben stock solution 

System suitability solution: Equivalent to 0.18 µg/mL of dexmedetomidine free base from USP Dexmedetomidine Hydrochloride RS and 0.25 µg/mL of butylparaben from Butylparaben solution in water 

Standard solution: Equivalent to 0.2 µg/mL of dexmedetomidine free base from USP Dexmedetomidine Hydrochloride RS in water Sensitivity solution: Equivalent to 0.04 µg/mL of dexmedetomidine free base from USP Dexmedetomidine Hydrochloride RS in water from the Standard solution 

Sample solution: Use the neat Injection as is. 

Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC 

Detector: UV 210 nm 

Column: 4.6-mm × 15-cm; 5-µm packing L1 

Column temperature: 30° Flow rate: 1 mL/min Injection volume: 25 µL 

Run time: NLT 3 times the retention time of dexmedetomidine 

System suitability 

Samples: System suitability solution, Standard solution, and Sensitivity solution 

Suitability requirements 

Resolution: NLT 4.0 between butylparaben and dexmedetomidine, System suitability solution 

Relative standard deviation: NMT 10.0%, Standard solution 

Signal-to-noise ratio: NLT 10, Sensitivity solution 

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of each impurity in the portion of Injection taken: 

Result = (r_u/r_s) x (C_s/C_u) × (M_r1/M_r2) × 100 

r_u = peak response of each impurity from the Sample solution 

r_s = peak response of dexmedetomidine from the Standard solution 

C_s = concentration of USP Dexmedetomidine Hydrochloride RS in the Standard solution (µg/mL) 

C_u = nominal concentration of dexmedetomidine in the Sample solution (µg/mL) 

M_r1 = molecular weight of dexmedetomidine free base, 200.28 

M_r2 = molecular weight of dexmedetomidine hydrochloride, 236.74 

Acceptance criteria: Disregard peaks below 0.02%. 

Any individual impurity: NMT 0.5% 

Total impurities: NMT 0.7% 

5 SPECIFIC TESTS 

Bacterial Endotoxins Test 〈85〉: NMT 2.5 USP Endotoxin Units/µg of dexmedetomidine free base 

Sterility Tests 〈71〉: Meets the requirements 

pH 〈791〉: 4.5–7.0 

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

Other Requirements: Meets the requirements in Injections and Implanted Drug Products 〈1〉 

6 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve in single-dose, clear, glass vials. Store at controlled room temperature. 

Labeling: Label it to indicate that it is to be diluted with 0.9% Sodium Chloride Injection USP for intravenous use. 

USP Reference Standards 〈11〉 

USP Dexmedetomidine Hydrochloride RS