Carisoprodol 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

Carisoprodol Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of carisoprodol (C₁₂H₂₄N₂O₄).

2 IDENTIFICATION

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

Change to read:

B. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197A (CN 1-May-2020)

Standard: Use a suitable portion of USP Carisoprodol RS.

Sample: Powder a Tablet and use a suitable portion to prepare a specimen.

Analysis

Samples: Standard and Sample

Compare the background corrected spectra in the range between 4000 and 400 cm−1.

Acceptance criteria: The spectrum obtained from the Sample shows bands at approximately 3445, 1689, 1604, 1525, 1410, 1244, 1072, and 780 cm−1, similar to the spectrum from the Standard. [Note—Peak positions may vary slightly between instruments (±10 cm−1). Other peaks may be present in the spectra that do not appear on the list.]

3 ASSAY

3.1 Procedure

Diluent: Acetonitrile and water (50:50)

Mobile phase: Acetonitrile and water (25:75)

System suitability solution: 0.1 mg/mL each of USP Carisoprodol Related Compound A RS, USP Meprobamate RS, and USP Carisoprodol RS in Diluent

Standard solution: 2.5 mg/mL of USP Carisoprodol RS in Diluent

Sample solution: Nominally 2.5 mg/mL of carisoprodol in Diluent prepared as follows. Transfer a quantity equivalent to the label claim of carisoprodol from powdered Tablets (NLT 20) to a suitable volumetric flask, and fill 50% of the flask volume with Diluent. Place in an ultrasonic bath for 30 min, and shake mechanically for 60 min. Dilute with Diluent to volume. Pass a portion of this solution through a suitable membrane filter, and use the filltrate as the Sample solution.

3.2 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 200 nm

Column: 4.6-mm × 15-cm; 4-μm packing L1

Column temperature: 30°

Flow rate: 1.5 mL/min

Injection volume: 25 μL

Run time: 1.5 times the retention time of carisoprodol

3.3 System suitability

Samples: System suitability solution and Standard solution

[Note—See Table 1 for the relative retention times.]

3.4 Suitability requirements

Resolution: NLT 1.5 between carisoprodol related compound A and meprobamate, System suitability solution

Tailing factor: NMT 2.5 for the carisoprodol peak, Standard solution

Relative standard deviation: NMT 2.0% for the carisoprodol peak, Standard solution

3.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of carisoprodol (C₁₂H₂₄N₂O₄) in the portion of Tablets taken:

Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response of carisoprodol from the Sample solution

r_S = peak response of carisoprodol from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: 0.05 M phosphate buffer, pH 6.9 (see Reagents, Indicators, and Solutions—Buffer Solutions) containing 5 units of α-amylase per mL; 900 mL

[Note—Use only freshly prepared solutions containing α-amylase; and equilibrate the Medium at 37° for NMT 1 h before beginning the

Dissolution test.]

Apparatus 2: 75 rpm

Time: 60 min

Mobile phase: Acetonitrile and water (40:60)

System suitability solution: 2.4 mg/mL of 2-methyl-2-propyl-1,3-propanediol and 3.4 mg/mL of USP Carisoprodol RS in Mobile phase

Standard solution: 0.4 mg/mL of USP Carisoprodol RS in Medium

[Note—A volume of acetonitrile not exceeding 2% of the final volume of solution may be used to aid in dissolving carisoprodol.]

Sample solution: Pass a portion of the solution under test through a suitable filter.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: Refractive index

Column: 3.9-mm × 30-cm; packing L1

Temperatures

Column: 30 ± 1°

Detector: 30 ± 1°

Flow rate: 2 mL/min

Injection volume: 150 μL

System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for 2-methyl-2-propyl-1,3-propanediol and carisoprodol are about 0.5 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 2.0 between 2-methyl-2-propyl-1,3-propanediol and carisoprodol, System suitability solution

Relative standard deviation: NMT 2.0% for three replicate injections of the Standard solution

Analysis

Samples: Standard solution and Sample solution

Record the peak responses, and measure the heights for the major peaks.

Calculate the percentage of the labeled amount of carisoprodol (C₁₂H₂₄N₂O₄) dissolved:

Result = (r_U/r_S) × (C_S /L) × V × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

L = label claim (mg/Tablet)

V = volume of Medium, 900 mL

Tolerances: NLT 80% (Q) of the labeled amount of carisoprodol (C₁₂H₂₄N₂O₄) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

Organic Impurities

Diluent, Mobile phase, System suitability solution, and Chromatographic system: Proceed as directed in the Assay.

Standard solution: 0.01 mg/mL of USP Carisoprodol RS in Diluent

Sample solution: Nominally 10 mg/mL of carisoprodol in Diluent prepared as follows. Transfer a quantity equivalent to four times the label claim of carisoprodol from powdered Tablets (NLT 20 Tablets) to a suitable volumetric flask, and fill 50% of the flask volume with Diluent.

Place in an ultrasonic bath for 30 min, and shake mechanically for 60 min. Dilute with Diluent to volume. Pass a portion of this solution through a suitable membrane filter, and use the filtrate as the Sample solution.

System suitability

Samples: System suitability solution and Standard solution

[Note—See Table 1 for the relative retention times.]

Suitability requirements

Resolution: NLT 1.5 between carisoprodol related compound A and meprobamate, System suitability solution

Tailing factor: NMT 2.5 for the carisoprodol peak, Standard solution

Relative standard deviation: NMT 5.0% for the carisoprodol peak for three replicate injections of the Standard solution

Analysis

Samples: Standard solution and Sample solution Identify the specified impurities using the relative retention times given in Table 1.

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

Result = (r_U/r_S) x (C_S/C_U) × (1/F) × 100

r_U = peak response of each impurity from the Sample solution

r_S = peak response of carisoprodol from the Standard solution

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

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

F = relative response factor (see Table 1)

Acceptance criteria: See Table 1.

Table 1

_a 2-Hydroxymethyl-2-methylpentyl isopropylcarbamate.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers at controlled room temperature.

USP Reference Standards 〈11〉

USP Carisoprodol RS

USP Carisoprodol Related Compound A RS

2-Hydroxymethyl-2-methylpentyl carbamate.

C₈H₁₇NO₃ 175.23