Thioridazine Hydrochloride Oral Solution
DEFINITION
Thioridazine Hydrochloride Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of thioridazine hydrochloride (C21H26N2S2·HCl).
[Note—Throughout the following procedures, protect samples, the Reference Standard, and the solutions containing them by conducting the procedures without delay, under subdued light, or by using low-actinic glassware. ]
IDENTIFICATION
• A. Identification—Organic Nitrogenous Bases 
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Sample solution:
2 mg/mL of thioridazine hydrochloride from a volume of Oral Solution in water. [Note—Use 2 mL of sodium bicarbonate solution (1 in 12) in place of the 2 mL of 1 N sodium hydroxide specified in the test. ]
Acceptance criteria:
Meets the requirements
ASSAY
[Note—Conduct this procedure with minimum exposure to light. ]
• Procedure
Diluent:
Shake 125 mL of chloroform with 5 mL of ammonium hydroxide in a separator, slowly filter the bottom layer through filter paper containing anhydrous sodium sulfate, and discard the top layer.
Standard solution:
6 µg/mL of USP Thioridazine Hydrochloride RS in Diluent
Sample stock solution:
Nominal concentration of 0.6 mg/mL in chloroform prepared as follows: Pipet a portion of Oral Solution, equivalent to 120 mg of thioridazine hydrochloride, into a separator containing 15 mL of water. Render alkaline with ammonium hydroxide, and extract with three 25-mL portions of Diluent. Filter the extracts through a pledget of glass wool into a 200-mL volumetric flask. Rinse the filter, and add chloroform to volume.
Sample solution:
Nominally 6 µg/mL in Diluent from Sample stock solution
Instrumental conditions
Mode:
UV-Vis
Analytical wavelength:
265 nm
Cell:
1 cm
Blank:
Diluent
Analysis
Samples:
Standard solution, Sample solution, and Blank
Calculate the percentage of thioridazine hydrochloride (C21H26N2S2·HCl) in the portion of Oral Solution taken:
Result = (AU/AS) × (CS/CU) × 100
| AU | = | = absorbance of the Sample solution |
| AS | = | = absorbance of the Standard solution |
| CS | = | = concentration of USP Thioridazine Hydrochloride RS in the Standard solution (µg/mL) |
| CU | = | = nominal concentration of thioridazine hydrochloride in the Sample solution (µg/mL) |
Acceptance criteria:
90.0%–110.0%
OTHER COMPONENTS
• Alcohol Determination 611:
NMT 4.75% of C2H5OH
611:
NMT 4.75% of C2H5OH
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight, light-resistant containers, and store at controlled room temperature.
• Labeling:
Label it to indicate that it is to be diluted to appropriate strength with water or other suitable fluid prior to administration.
• USP Reference Standards 11
11
USP Thioridazine Hydrochloride RS 
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Hariram Ramanathan, M.S.
Associate Scientific Liaison 1-301-816-8313 |
(SM42010) Monographs - Small Molecules 4 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 4848