Tiagabine Hydrochloride Compounded Oral Suspension

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

Tiagabine Hydrochloride Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of tiagabine hydrochloride (C₂₀H₂₅NO₂S₂ · HCl). Prepare Tiagabine Hydrochloride Compounded Oral Suspension 1 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

Calculate the required quantity of each ingredient for the total amount to be prepared. If using tablets, place the required number of tablets in a suitable mortar, and comminute the tablets to a fine powder or add Tiagabine Hydrochloride powder. Add the Vehicle in small portions and triturate to make a smooth paste. Add increasing volumes of the Vehicle to make a tiagabine hydrochloride suspension that is pourable.

Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add enough of the Vehicle to bring to final volume, and mix well.

2 ASSAY

PROCEDURE

Mobile phase: Acetonitrile and 5 mM octanesulfonic acid (50:50). Pass through a suitable filter of 0.45-µm pore size and degas. Standard stock solution: 1.0 mg/mL of USP Tiagabine Hydrochloride RS in methanol

Standard solution: Transfer 0.2 mL of Standard stock solution to a 10-mL volumetric flask, and dilute with Mobile phase to volume to obtain a solution containing 20 µg/mL of tiagabine hydrochloride. Centrifuge, and pass through a suitable filter of 0.22-µm pore size.

Sample solution: Shake thoroughly by hand each bottle of Oral Suspension. Centrifuge, and pass through a suitable filter of 0.22-µm pore size. Accurately pipet 0.2 mL of the Oral Suspension to a 10-mL volumetric flask, and dilute with Mobile phase to volume to obtain a nominal concentration of 20 µg/mL of tiagabine hydrochloride.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 240 nm

Flow rate: 0.4 mL/min

Column: 3.0-mm × 15-cm; 5-µm packing L10 Injection volume: 10 µL

System suitability

Sample: Standard solution

[NOTE—The retention time of the tiagabine hydrochloride peak is 3.2 min.] Suitability requirements

Relative standard deviation: NMT 1.7% Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of tiagabine hydrochloride (C₂₀H₂₅NO₂S₂ · HCl) in the volume of Oral Suspension taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Tiagabine Hydrochloride RS in the Standard solution (µg/mL)

C_U = nominal concentration of tiagabine hydrochloride in the Sample solution (µg/mL)

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

PH 〈791〉: 4.0–4.5

4 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Package in tight, light-resistant containers. Store at controlled room temperature or in a refrigerator.

BEYOND-USE DATE: NMT 90 days after the date on which it was compounded, when stored in a refrigerator; NMT 60 days after the date it was compounded, when stored at controlled room temperature

LABELING: Label it to state that it is to be well shaken before use, and to state the Beyond-Use Date.

USP REFERENCE STANDARDS 〈11〉

USP Tiagabine Hydrochloride RS