Tetracycline Hydrochloride Capsules

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

Tetracycline Hydrochloride Capsules contain NLT 90.0% and NMT 125.0% of the labeled amount of tetracycline hydrochloride (C₂₂H₂₄N₂O₈ · HCl).

2 IDENTIFICATION

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

B. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Procedure

Solution A: Dilute 1 mL of phosphoric acid with water to 1 L.

Solution B: Acetonitrile

Mobile phase: See Table 1.

Table 1

System suitability solution: 25 μg/mL each of USP Anhydrotetracycline Hydrochloride RS, USP 4-Epianhydrotetracycline Hydrochloride RS, USP Epitetracycline Hydrochloride RS, and USP Tetracycline Hydrochloride RS in Solution A

Standard solution: 100 μg/mL of USP Tetracycline Hydrochloride RS in Solution A. [Note—If needed, dilute the Standard solution concentration for Identification B.]

Sample solution: Nominally equivalent to 100 μg/mL of tetracycline hydrochloride in Solution A from NLT 20 Capsules prepared as follows.

Transfer a portion of Capsule contents, equivalent to 25 mg of tetracycline hydrochloride, to a 250-mL volumetric flask. Dissolve with the flaid of sonication, and dilute with Solution A to volume. Pass through a syringe filter of 0.22-μm pore size and discard the first 2 mL of the filtrate. [Note—If needed, dilute the Sample solution concentration for Identification B.]

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 280 nm. For Identi

cation B, use a diode array detector in the range of 220–400 nm.

Column: 4.6-mm × 15-cm; 3-μm packing L1

Temperatures

Autosampler: 4°

Column: 50°

Flow rate: 1.0 mL/min

Injection volume: 10 μL

System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for epitetracycline, tetracycline, 4-epianhydrotetracycline, and anhydrotetracycline are 0.9, 1.0, 1.6, and 1.8, respectively.]

Suitability requirements

Tailing factor: NMT 1.5, Standard solution

Resolution: NLT 2.5 between epitetracycline and tetracycline; NLT 2.5 between anhydrotetracycline and 4-epianhydrotetracycline, System suitability solution

Relative standard deviation: NMT 1.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of tetracycline hydrochloride (C₂₂H₂₄N₂O₈ · HCl) in the portion of Capsules taken:

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

r_U = peak response of tetracycline from the Sample solution

r_S = peak response of tetracycline from the Standard solution

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

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

P = potency of USP Tetracycline Hydrochloride RS (μg/mg)

F = correction factor, 0.001 mg/μg

Acceptance criteria: 90.0%–125.0%

4 PERFORMANCE TESTS

Change to read:

Dissolution 〈711〉

Test 1

Medium: Water; 900 mL

Apparatus 2: 75 rpm. Maintain a distance of 45 ± 5 mm between the blade and the inside bottom of the vessel.

Times

For Capsules labeled to contain 250 mg: 60 min

For Capsules labeled to contain 500 mg: 90 min

Standard solution: A known concentration of USP Tetracycline Hydrochloride RS in Medium

Sample solution: Pass a portion of the solution under test through a suitable filter. Dilute with Medium, if necessary.

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.) (IRA 1-May-2022)

Mode: UV

Analytical wavelength: 276 nm

Analysis:

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of tetracycline hydrochloride (C₂₂H₂₄N₂O₈ · HCl) dissolved:

Result = (A_U/A_S ) × (C_S /L) × V × D × 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

L = label claim (mg/Capsule)

V = volume of Medium, 900 mL

D = dilution factor for the Sample solution, if applicable (IRA 1-May-2022)

Tolerances: NLT 80% (Q) of the labeled amount of tetracycline hydrochloride (C₂₂H₂₄N₂O₈ · HCl) is dissolved.

Test 2: If the product complies with this test, the labeling indicates that the product meets USP Dissolution Test 2.

Medium: Water; 900 mL, deaerated

Apparatus 2: 75 rpm. Maintain a distance of 45 ± 5 mm between the blade and the inside bottom of the vessel.

Times

For Capsules labeled to contain 250 mg: 30 and 60 min

For Capsules labeled to contain 500 mg: 30, 60, and 90 min

Standard solution: A known concentration of USP Tetracycline Hydrochloride RS in Medium

Sample solution: At the times specified, withdraw a known volume of the solution under test and pass it through a suitable filter. Dilute with

Medium, if necessary. Replace the volume withdrawn with the same amount of Medium, preheated at 37.0 ± 0.5°.

Blank: Medium

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.) (IRA 1-May-2022)

Mode: UV

Analytical wavelength: 276 nm

Analysis

Samples: Standard solution and Sample solution

Calculate the concentration (C_i ) of tetracycline hydrochloride (C₂₂H₂₄N₂O₈ · HCl) in the sample withdrawn at each time point (i):

Result = (A_U /A ) × C_S × D

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

D = dilution factor for the Sample solution, if applicable

Calculate the percentage of the labeled amount of tetracycline hydrochloride (C₂₂H₂₄N₂O₈ · HCl) dissolved at each time point (i):

Result₁ = C₁ × V × (1/L) × 100

Result₂ = [(C₂ × V) + (C₁ × V_S )] × (1/L) × 100

Result₃ = {(C₃ × V) + [(C₂ + C₁ ) × V_S ]} × (1/L) × 100

C_i = concentration of tetracycline hydrochloride in the portion of sample withdrawn at the specified time point (mg/mL)

V = volume of Medium, 900 mL

L = label claim (mg/Capsule)

V_S = volume of the Sample solution withdrawn at each time point and replaced with Medium (mL) (IRA 1-May-2022)

Tolerances: See Table 2 and Table 3.

Table 2

Table 3

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

Change to read:

Organic Impurities

Solution A, Solution B, Mobile phase, Sample solution, and Chromatographic system: Proceed as directed in the Assay.

System suitability solution: 25 μg/mL each of USP Anhydrotetracycline Hydrochloride RS, USP 4-Epianhydrotetracycline Hydrochloride RS, USP Epitetracycline Hydrochloride RS, and USP Tetracycline Hydrochloride RS in Solution A

Standard solution 1: 0.5 μg/mL of USP Anhydrotetracycline Hydrochloride RS and 3 μg/mL of USP Epitetracycline Hydrochloride RS in Solution A

Standard solution 2: 3 μg/mL of USP 4-Epianhydrotetracycline Hydrochloride RS in Solution A

Standard solution 3: 0.1 μg/mL of USP Tetracycline Hydrochloride RS in Solution A (IRA 1-May-2022)

System suitability

Sample: System suitability solution

Suitability requirements

Resolution: NLT 2.5 between epitetracycline and tetracycline; NLT 2.5 between anhydrotetracycline and 4-epianhydrotetracycline

Relative standard deviation: NMT 2.0%

Analysis

Samples: Sample solution, Standard solution 1, Standard solution 2, and Standard solution 3

Calculate the percentage of anhydrotetracycline hydrochloride and epitetracycline hydrochloride in the portion of Capsules taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of anhydrotetracycline or epitetracycline from the Sample solution

r_S = peak response of the corresponding USP Reference Standard from Standard solution 1

C_S = concentration of the corresponding USP Reference Standard in Standard solution 1 (μg/mL)

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

Calculate the percentage of 4-epianhydrotetracycline hydrochloride in the portion of Capsules taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of 4-epianhydrotetracycline from the Sample solution

r_S = peak response of 4-epianhydrotetracycline from Standard solution 2

C_S = concentration of the USP 4-Epianhydrotetracycline Hydrochloride RS in Standard solution 2 (μg/mL)

C_U = nominal concentration of tetracycline hydrochloride in the Sample solution (μg/mL) (IRA 1-May-2022)

Calculate the percentage of each unspecified impurity in the portion of Capsules taken:

Result = (r_U/r_S) × (C_S/C_U) (IRA 1-May-2022) × 100

r_U = peak response of each unspecified impurity from the Sample solution

r_S = peak response of tetracycline from Standard solution 3 (IRA 1-May-2022)

C_S = concentration of USP Tetracycline Hydrochloride RS in Standard solution 3 (IRA 1-May-2022) (μg/mL)

C_U = nominal concentration of tetracycline hydrochloride in the Sample solution (μg/mL) (IRA 1-May-2022)

Acceptance criteria: See Table 4. The reporting threshold is (IRA 1-May-2022) 0.05%.

Table 4

^a 2-Acetyl-2-decarbamoyltetracycline; (4S,4aS,5aS,6S,12aS)-2-acetyl-4-(dimethylamino)-3,6,10,12,12a-pentahydroxy-6-methyl-4a,5a,6,12a-tetrahydrotetracene-1,11(4H,5H)-dione.

^b Process impurities that are controlled in the drug substance are not to be reported. They are not to be included in total impurities. They are listed here for information only.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

Labeling: When more than one Dissolution test is given, the labeling states the test used only if Test 1 is not used.

Change to read:

USP Reference Standards 〈11〉

USP Anhydrotetracycline Hydrochloride RS

(4S,4aS,12aS)-4-(Dimethylamino)-3,10,11,12a-tetrahydroxy-6-methyl-1,12-dioxo-1,4,4a,5,12,12a-hexahydrotetracene-2-carboxamide monohydrochloride.

C₂₂H₂₂N₂O₇ · HCl 462.88 (IRA 1-May-2022)

USP 4-Epianhydrotetracycline Hydrochloride RS

(4R,4aS,12aS)-4-(Dimethylamino)-3,10,11,12a-tetrahydroxy-6-methyl-1,12-dioxo-1,4,4a,5,12,12a-hexahydrotetracene-2-carboxamide hydrochloride.

C₂₂H₂₂N₂O₇ · HCl 462.88 (IRA 1-May-2022)

USP Epitetracycline Hydrochloride RS

(4R,4aS,5aS,6S,12aS)-4-(Dimethylamino)-3,6,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydrotetracene-2- carboxamide monohydrochloride.

C₂₂H₂₄N₂O₈ .HCl 480.90 (IRA 1-May-2022)

USP Tetracycline Hydrochloride RS