Nateglinide

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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C₁₉H₂₇NO₃            317.42

d-Phenylalanine, N-[[trans-4-(1-methylethyl)cyclohexyl] carbonyl]-;

(−)-N-[(trans-4-Isopropylcyclohexyl)carbonyl-d-phenylalanine CAS RN: 105816-04-4; UNII: 41X3PWK4O2.

1 DEFINITION

Nateglinide contains NLT 98.0% and NMT 102.0% of C, H,NO₂, calculated on the dried basis.

2 IDENTIFICATION

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197K

B. 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: 8.5 g/L of anhydrous dibasic sodium phosphate in water. Adjust with phosphoric acid to a pH of 7.5.

Mobile phase: Methanol and Buffer (1:1)

System suitability stock solution: 0.2 mg/mL each of USP Nateglinide Related Compound C RS and DL-phenylalanine in methanol. [NOTE-Sonicate, if necessary.]

System suitability solution: Transfer USP Nateglinide RS to a suitable volumetric flask, dissolve first in methanol, using 45% of the final volume, add System suitability stock solution equal to 5% of the final volume, and then dilute with Buffer to volume to obtain a solution containing about 1.0 mg/mL of nateglinide and about 0.01 mg/mL each of nateglinide related compound C and DL-phenylalanine.

Standard solution: 1.0 mg/ml of nateglinide prepared as follows: transfer USP Nateglinide RS to a suitable volumetric flask, dissolve first in methanol, using 50% of the final volume, and then dilute with Buffer to volume.

Sample solution: Transfer about 100 mg of Nateglinide to a 100-ml volumetric flask, dissolve in 50 mL of methanol, and dilute with Buffer to volume.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 210 nm

Column: 6-mm x 15-cm; 6-µm packing L71 (see Chromatographic Reagents under Reagents, Indicators, and Solutions)

Column temperature: 30°

Flow rate: 1 mL/min

Injection size: 20 µL

System suitability

Samples: System suitability solution and Standard solution

Suitability requirements

Resolution: NLT 0.9 between nateglinide related compound C and nateglinide, System suitability solution

Relative standard deviation: NMT 1.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of nateglinide (C₁₉H₂₇NO₃) in the portion of Nateglinide 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 Nateglinide RS in the Standard solution (mg/mL)

C_u = concentration of Nateglinide in the Sample solution (mg/mL)

Acceptance criteria: 98.0%–102.0% on the dried basis

4 IMPURITIES

RESIDUE ON IGNITION (281): NMT 0.1%

LIMIT OF NATEGLINIDE RELATED COMPOUND A AND OTHER IMPURITIES

Buffer: 7.8 g/L of monobasic sodium phosphate in water. Adjust with phosphoric acid to a pH of 2.5.

Mobile phase: Acetonitrile and Buffer (7:13)

System suitability stock solution: Dissolve USP Nateglinide Related Compound A RS in acetonitrile to obtain a solution containing about 0.6 mg/mL. Further dilute this solution with Mobile phase to obtain a solution containing about 0.12 mg/mL.

System suitability solution: Transfer an amount of USP Nateglinide RS to a suitable volumetric flask, dissolve first in acetonitrile using 10% of the final volume, then add System suitability stock solution equal to 10% of the final volume, and dilute with Mobile phase to volume to obtain a solution containing about 6 mg/mL of nateglinide and about 0.012 mg/ml, of nateglinide related compound A.

Standard solution: Dissolve USP Nateglinide RS in acetonitrile to obtain a solution having a known concentration of about 0.3 mg/mL. Further dilute this solution with Mobile phase to obtain a solution having a known concentration of about 0.06 mg/ml..

Sample solution: Transfer 60 mg of Nateglinide to a 10-mL volumetric flask, dissolve in a minimal amount of acetonitrile, and dilute with Mobile phase to volume.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 210 nm

Column: 3.9-mm x 5-cm; 5-µm packing L7

Column temperature: 40°

Flow rate: 2 mL/min

Injection size: 100 µL

Run time: 5 times the retention time of nateglinide

System suitability

Samples: System suitability solution and Standard solution

Suitability requirements

Resolution: NLT 2.5 between nateglinide related compound A and nateglinide, System suitability solution

Relative standard deviation: NMT 2.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

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

Result = (r_u /r_s ) × (C_s /C_u ) × (1/F) × 100

r_u = peak response of each impurity from the Sample solution

r_s = peak response of nateglinide from the Standard solution

C_s = concentration of USP Nateglinide RS in the Standard solution (mg/mL)

C_u = concentration of Nateglinide in the Sample solution (mg/mL)

F = relative response factor (see Table 1)

Acceptance criteria

Individual impurities: See Table 1.

Table 1

^a trans-4-Isopropylcyclohexylcarboxylic acid.

^b N-(trans-4-Ethylcyclohexylcarbonyl)-d-phenylalanine.

^c N-(trans-4-Isopropylcyclohexylcarbonyl)-d-phenylalanine-d-phenylalanine.

^d N-(trans-4-isopropylcyclohexylcarbonyl)-d-phenylalanine-ethyl ester.

4.1 LIMIT OF NATEGLINIDE RELATED COMPOUND B

Mobile phase: 0.77 g/L of ammonium acetate in methanol.

[NOTE-The following solutions are stable for up to 48 h when stored in a refrigerator.]

System suitability solution: 10 mg/mL of USP Nateglinide RS and 0.02 mg/mL of USP Nateglinide Related Compound B RS in methanol

Standard solution: 0.02 mg/mL of USP Nateglinide Related Compound B. RS in methanol. [NOTE-Nateglinide related compound B is N-(trans-4-isopropyl-cyclohexylcarbonyl)-1-phenylalanine.]

Sample solution: 10 mg/mL of Nateglinide in methanol

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 220 nm

Column: 4-mm x 25-cm or 4.6-mm x 25-cm; 5-um packing L72 (see Chromatographic Reagents under Reagents, Indicators, and Solutions)

Column temperature: 40°

Flow rate: 0.8 mL/min. [NOTE-The flow rate can be adjusted as needed to achieve a recommended retention time of nateglinide related compound B at about 25 min.]

Injection size: 10 µL

System suitability

[NOTE-The elution order is nateglinide related compound B, followed by the nateglinide peak.]

Samples: System suitability solution and Standard solution

Suitability requirements

Resolution: NLT 0.8 between nateglinide related compound B and nateglinide, System suitability solution

Relative standard deviation: NMT 5%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of nateglinide related compound B in the portion of Nateglinide taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of nateglinide related compound B from the Sample solution

r_s = peak response of nateglinide related compound B from the Standard solution

C_s = concentration of USP Nateglinide Related Compound B RS in the Standard solution (mg/mL)

C_u = concentration of Nateglinide in the Sample solution (mg/mL)

Acceptance criteria: NMT 0.2%

4.2 LIMIT OF NATEGLINIDE RELATED COMPOUND C AND PHENYLALANINE

Mobile phase, System suitability solution, Standard solution, Sample solution, and Chromatographic system: Proceed as directed in the

Assay

Diluted standard solution: Dilute the Standard solution with Mobile phase to obtain a solution having a known concentration of about 0.01 mg/mL of nateglinide.

Analysis

Samples: Sample solution and Diluted standard solution

Calculate the percentage of each specied impurity listed in Table 2 in the portion of Nateglinide taken:

Result = (r_u /r_s ) × (C_s /C_u ) × (1/F) × 100

r_u = peak response of each impurity from the Sample solution

r_s = peak response of nateglinide from the Diluted standard solution

C_s = concentration of nateglinide in the Diluted standard solution (mg/mL)

C_u = concentration of Nateglinide in the Sample solution (mg/mL)

F = relative response factor of each individual impurity (see Table 2)

Acceptance criteria

Individual impurities: See Table 2.

Table 2

^a N-(cis-4-isopropylcyclohexylcarbonyl)-d-phenylalanine.

Total impurities: The sum of all impurities found in the tests for Limit of Nateglinide Related Compound A and Other Impurities, Limit of

Nateglinide Related Compound B, and Limit of Nateglinide Related Compound C and Phenylalanine is NMT 0.5%.

5 SPECIFIC TESTS

Loss on Drying 〈731〉: Dry a sample at 105° for 2 h: it loses NMT 0.5% of its weight.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers. Store at room temperature.

USP Reference Standards 〈11〉

USP Nateglinide RS

(−)-N-[(trans-4-Isopropylcyclohexyl)carbonyl-d-phenylalanine.

C₁₉H₂₇NO₃ 317.42

USP Nateglinide Related Compound A RS

trans-4-Isopropylcyclohexylcarboxylic acid.

C₁₀H₁₈NO₂           170.2

USP Nateglinide Related Compound B RS

N-(trans-4-Isopropylcyclohexylcarbonyl)-l-phenylalanine.

C₁₉H₂₇NO₃           317.4

USP Nateglinide Related Compound C RS

Nateglinide cis-isomer, N-(cis-4-isopropylcyclohexylcarbonyl)-d-phenylalanine.

C₁₉H₂₇NO₃           317.4