Estazolam Tablets

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

Estazolam Tablets contain an amount of Estazolam equivalent to NLT 90.0% and NMT 110.0% of the labeled amount of estazolam (C₁₆H₁₁CIN₄)

2 IDENTIFICATION

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

3 ASSAY

PROCEDURE

Buffer: 2.8 g/L of potassium phosphate, monobasic in water. Adjust to a pH of 6.5 with 1 N NaOH.

Mobile phase: Acetonitrile, methanol, and Buffer (10:35:55)

Standard solution: 0.02 mg/mL of USP Estazolam RS in Mobile phase

Sample solution: 0.02 mg/mL of Estazolam in Mobile phase, from NLT 20 finely powdered Tablets. Nore-Sonicate for 5 min. Pass a portion through a suitable filter with no glass prefilter.]

Chromatographic system

(See Chromatography (621), System Suitability)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm x 15-cm; 3-um packing L11

Flow rate: 1 mL/min

Injection size: 25 μL

Run time: 2.7 times the retention time of the estazolam peak

System suitability

Sample: Standard solution

Suitability requirements

Talling factor: NMT 2.0%

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of C₁₆H₁₁CIN₄ in the portion of Tablets taken:

Result = (r_U/(r_S) × (C_S /C_U) x 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Estazolam RS in the Standard solution (mg/mL)

C_U = concentration of Estazolam in the Sample solution (mg/mL)

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

DISSOLUTION (711)

Medium: Water, 900 ml, deaerated

Apparatus 2: 50 rpm

Time: 30 min

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

Standard stock solution: 0.1 mg/mL of USP Estazolam RS in methanol

Standard solution: Dilute the Standard stock solution with Medium to obtain a final concentration of about (L/1000) mg/mL, where L is the Tablet label claim in mg.

Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-um pore size, discarding the first few ml.

Chromatographic system

(See Chromatogranby (621). System Suitability.)

Proceed as directed in the Assay, except for the injection size and run time.

Injection size: 100 µL

Run time: 1.6 times the retention time of estazolam

System suitability: Proceed as directed in the Assay

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of estazolam dissolved:

Result = (r_U/(r_S) × (C_S /L) x 100

r_U = peak response of estazolam from the Sample solution

r_S = peak response of estazolam from the Standard solution

C_S = concentration of USP Estazolam RS in the Standard solution (mg/mL)

L = Tablet label claim (mg)

V = volume of Medium (mL), 900

Tolerances: NLT 80% (Q) of the labeled amount of estazolam is dissolved.

UNIFORMITY OF DOSAGE UNITS (905): Meet the requirements

5 IMPURITIES

ORGANIC IMPURITIES

PROCEDURE

Buffer, Mobile phase, Standard solution, and Sample solution: Proceed as directed in the Assay

Chromatographic system

(See Chromatography (621). System Suitability)

Proceed as directed in the Assay, except for the injection size and run time.

Injection size: 25 µL. for the Standard solution and 50 µl for the Sample solution

Run time: 4 times the retention time of estazolam

System suitability: Proceed as directed in the Assay.

Analysis

Sample: Sample solution

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

Result = (r_u/r_s) x 100

r_u = peak response of each individual impurity from the Sample solution

r_s = sum of the responses of all peaks from the Sample solution

Acceptance criteria

Any individual unspecified degradation product: NMT 0.5%

Total impurities: NMT 1.0%

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight, light-resistant containers. Store at controlled room temperature.