Doxycycline Hyclate Delayed-Release 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

Doxycycline Hyclate Delayed-Release Tablets contain an amount of Doxycycline Hyclate equivalent to NLT 90.0% and NMT 120.0% of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈).

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

Protect solutions containing doxycycline from light.

Solution A: Transfer 3.1 g of monobasic potassium phosphate, 0.5 g of edetate disodium, and 0.5 ml, of triethylamine to a 1000-mL volumetric flask. Add about 850 ml of water and mix. Dilute with water to volume and adjust with 1 N sodium hydroxide to a pH of 8.5 t 0.1. Pass through a suitable filter of 0.22-um pore size.

Solution B: Methanol

Mobile phase: See Table 1.

Diluent: 0.01 N hydrochloric acid

Standard solution: 0.12 mg/mL of USP Doxycycline Hyclate RS in Diluent. Sonicate as needed to dissolve.

Sample solution: Nominally 0.1 mg/ml. of doxycycline from NLT 20 Tablets prepared as follows. Transfer a suitable portion of finely powdered Tablets to a suitable volumetric flask. Add 80% of the final volume of Diluent, sonicate for about 15 min, shake for about 15 min, and dilute with Diluent to volume. Pass through a suitable filter of 0.2-um pore size and use the filtrate for analysis.

Chromatographic system

(See Chromatography (621). System Suitability)

Mode: LC

Detector: UV 270 nm. For Identification B, use a diode array detector in the range of 200-400 nm.

Column: 2.1-mm x 5-cm, 1.7-um packing 17. [NOTE-A 1.7-um guard column with packing 17 was used during method validation.]

Column temperature: 60°

Flow rate: 0.6 mL/min

Injection volume: 5 µl

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.5

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) in the portion of Tablets taken:

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

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Doxycycline Hyclate RS, in the Stardard solution (mg/ml)

C_U = nominal concentration of doxycycline in the Sample sulation (mg/ml)

P = potency of doxycycline in USP Doxycycline Hyclate RS (µg/mg)

F = conversion factor 0.001 mg/μg

Acceptance criteria: 90.0%-120.0%

PERFORMANCE TESTS

DISSOLUTION (711)

Protect solutions containing doxycycline from light.

Test 1: Proceed as directed for Dissolution (711). Procedure. Apparatus 1 and Apparatus 2. Delayed-Release Dosage Forma. Method B

Procedure

Acid stage

Medium: 0.06 N hydrochloric acid; 900 ml, degassed with helium

Apparatus 1: 50 rpm

Time: 20 min

Standard solution: 0.128 mg/mL of USP Doxycycline Hyclate RS in Medium. Calculate the concentration, C, in mg/mL, of doxycycline using the designated potency, in µg/mg, of doxycycline in USP Doxycycline Hyclate RS. [NOTE-Sonicate if necessary to dissolve

Sample solution: Pass portions of the solution under test through a suitable PVDF filter of 0.45-um pore size.

Detector: UV 346 nm

Cell: 0.1-cm quartz

Blank: Medium

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) dissolved:

Result = (A_U/A_S) x (C_S/L) x V x 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

CS = concentration of doxycycline in the Standard solution (mg/mL)

L = label claim (mg/Tablet)

V = volume of Medium, 900 mL

Tolerances

Level 1 (6 Tablets tested): No individual value is more than 30% of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) dissolved in 20 min.

(CHNO) in 20 min.

Level 2 (6 Tablets tested): NMT 2 individual values of the 12 tested are greater than 30% of the labeled amount of doxycycline

Buffer stage

Conduct this stage of testing on separate Tablets, selecting those that were not previously subjected to the Acid stage testing

Medium: pH 5.5 neutralized phthalate buffer (see Beagents Indicators, and Solutions-Solutions, Buffer Solutions): 900 mL, degassed

Apparatus 1: 50 rpm

Time: 30 min

Standard solution: 0.128 mg/mL of USP Doxycycline Hyclate RS in Medium. Calculate the concentration, C., in mg/ml, of doxycycline using the designated potency, in µg/mg, of doxycycline in USP Doxycycline Hyclate RS. [Nors-Sonicate if necessary to dissolve.

Sample solution: Pass portions of the solution under test through a suitable PVDF filter of 0.45-um pore size

Analysis: Determine the percentage of doxycycline (C₂₂H₂₄N₂O₈) dissolved by the procedure described for the Acld stage.

Tolerances: NLT 85% (Q) of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) is dissolved.

Test 2: If the product complies with this test, the labeling indicates that the product meets USP Dissolution Test 2. Proceed as directed for Dissolution (711), Procedure. Apparatus 1 and Apparatus 2. Delayed-Release Dosage Forms. Method B Procedure.

Acid stage

Medium, Apparatus 1, Time, Blank, and Analysis: Proceed as directed for Acid stage in Test 1.

Standard solution: (L / 900) * mg / m * L of USP Doxycycline Hyclate RS in Medium. Calculate the concentration, C S' in mg/ml, of doxycycline using the designated potency, in mu*g / m * g of doxycycline in USP Doxycycline HHyclate RS. Sonicate if necessary to dissolve.

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

Detector: UV 345 nm

Cell: See Table 2.

Tolerances

Level 1 (6 Tablets tested): No individual value is more than 50% of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) dissolved in 20 min

Level 2 (6 Tablets tested): NMT 2 individual values of the 12 tested are greater than 50% of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) IN 20 min.

Buffer stage

Conduct this stage of testing on separate Tablets, selecting those that were not previously subjected to the Acid stage testing.

Medium: pH 5.5 neutralized phthalate buffer (see Reagents. Indicators, and Solutions-Solutions, Buffer Solutions), 1000 ml, degassed

Apparatus 1 and Analysis: Proceed as directed for Buffer stage in Test 1

Time: 45 min

Standard solution: (L/1000) mg/mL of USP Doxycycline Hyclate BS in Medium. Calculate the concentration, C_S in mg/mL of doxycycline using the designated potency, , in µg/mg of doxycycline in USP Doxycycline Hyclate RS. Sonicate if necessary to dissolve.

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

Detector and Cell: Proceed as directed for Acid stage in Test 2.

Tolerances: NLT 70% (Q) of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) is dissolved

Test 3: If the product complies with this test, the labeling indicates that the product meets USP Dissolution Test 3. Proceed as directed for Dissolution (711), Procedure, Apparatus 1 and Apparatus 2. Delayed Release Dosage Forms. Method B Procedure.

Acid stage

Apparatus 1 and Time: Proceed as directed for Acid stage in Test 1.

Medium: 0.06 N hydrochloric acid; 900 mL

Standard solution: Prepare the solutions from USP Doxycycline Hyclate RS in Medium as directed in Table 3. Calculate the concentration, Cin mg/mL, of doxycycline using the designated potency, in mu*g / m * g of doxycycline in USP Doxycycline Hvclate RS

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

Detector: UV 345 nm

Cell: 0.2 cm

Blank: Medium

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) dissolved:

Result = (A_U/A_S) x (C_S/L) x Vx100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

CS = concentration of doxycycline in the Standard solution (mg/mL)

L = label claim (mg/Tablet)

v = volume of Medium, 900 mL

Tolerances: See Jabin 4.

Buffer stage

Conduct this stage of testing on separate Tablets, selecting those that were not previously subjected to the Acid stage testing.

Medium: pH 5.5 neutralized phthalate buffer (see Reagents, Indicators, and Solutions-Solutions, Buffer Solutions): 1000 ml

Apparatus 1: 50 rpm

Time: 60 min

Standard solution: Prepare the solutions from USP Doxycycline Hyclate RS in Medium as directed in Table 5. Calculate the concentration, c_{x} mg/ml, of doxycycline using the designated potency, in mu*g / m * g of doxycycline in USP Doxycycline Hyclate RS

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

Detector: UV 345 nm

Cell: 0.2 cm

Blank: Medium

Samples: Standard solution and Sample solution

Analysis

Calculate the percentage of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) dissolved:

Result = (A_U/A_S) x (C_S/L) x Vx100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

CS = concentration of doxycycline in the Standard solution (mg/mL)

L = label claim (mg/Tablet)

V = volume of Medium, 900 mL

Tolerances: See Table 6

Test 4: If the product complies with this test, the labeling indicates that the product meets USP Dissolution Test 4. Proceed as directed for Dissolution (711), Procedure, Apparatus 1 and Apparatus 2. Delaved -Release Dosage Forms, Method B. Procedure,

Acid stage

Medium: 0.06 N hydrochloric acid; 900 ml, degassed

Apparatus 1: 50 rpm

Time: 20 min

Standard solution: 0.1 mg/ml of doxycycline from USP Doxycycline Hyclate RS in Medium, Calculate the concentration, C, in mg/ml, of doxycycline using the designated potency, in µg/mg, of doxycycline in USP Doxycycline Hyclate RS

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

Detector: UV 345 nm

Cell: 0.2-cm quartz

Blank: Medium

Analysis

Samples: Standard solution and Sample solution Calculate the percentage of the labeled amount of doxycycline ((C₂₂H₂₄N₂O₈) dissolved:

Result = (A_U/A_S) x (C_S/L) x Vx100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

CS = concentration of doxycycline in the Standard solution (mg/mL)

L = label claim (mg/Tablet)

V = volume of Medium, 900 mL

Tolerances

Level 1 (6 Tablets tested): No individual value is more than 30% of the labeled amount of doxycycline (CH,N,O,) dissolved in 20 min..

Level 2 (6 Tablets tested): NMT 2 individual values of the 12 tested are greater than 30% of the labeled amount of doxycycline (CH,N,O) dissolved in 20 min.

Buffer stage

Conduct this stage of testing on separate Tablets, selecting those that were not previously subjected to the Acid stage testing.

Medium: pH 5.5 neutralized phthalate buffer (see Boagents, indicators, and Solutions-Solutions Buffer Solutions); 1000 ml, degassed

Apparatus 1: 50 rpm

Time: 30 min

Standard solution: 0.1 mg/mL of doxycycline from USP Doxycycline Hyclate RS in Medium

Sample solution: Pass portions of the solution under test through a suitable filter. Calculate the concentration, C, in mg/ml, of

doxycycline using the designated potency, in µg/mg, of doxycycline in USP Doxycycline Hyclate RS

Blank: Medium

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) dissolved:

Result = (A_U/A_S) x (C_S/L) x Vx100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

CS = concentration of doxycycline in the Standard solution (mg/mL)

L = label claim (mg/Tablet)

V = volume of Medium,1900 mL

Tolerances: NLT 75% (Q) of the labeled amount of doxycycline (CHNO) is dissolved

Test 5: If the product complies with this test, the labeling indicates that the product meets USP Dissolution Test 5. Proceed as directed for Dissolution (711). Procedure Apparatus 1 and Apparatus 2. Delayed-Release Dosage Forms. Method B Procedure.

Acid stage

Medium: 0.06 N hydrochloric acid; 900 mL

Apparatus 1: 100 rpm

Time: 20 min

Standard solution: 0.06 mg/ml of doxycycline from USP Doxycycline Hyclate RS in Medium. Calculate the concentration, C, in mg/ml, of doxycycline using the designated potency, in µg/mg, of doxycycline in USP Doxycycline Hyclate RS

Sample solution: Pass portions of the solution under test through a suitable filter,

Detector: UV 345 mm

Cell: 1.0 cm

Blank: Medium

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈) dissolved:

Result = (A_U/A_S) x (C_S/L) x Vx100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

CS = concentration of doxycycline in the Standard solution (mg/mL)

L = label claim (mg/Tablet)

V = volume of Medium, 900 mL

Tolerances: See Table 7.

Buffer stage

Conduct this stage of testing on separate Tablets, selecting those that were not previously subjected to the Acid stage testing

Apparatus 1: 100 rpm

Medium: pH 5.5 neutralized phthalate buffer (see Reagents indicators and Solutions-Solutions, Buffer Solutions), 900 ml.

Time: 30 min

Standard solution: 0.06 mg/ml of doxycycline from USP Doxycycline Hyclate RS in Medium. Calculate the concentration, C, in mg/ml, of doxycycline using the designated potency, in µg/mg, of doxycycline in USP Doxycycline Hyclate RS

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

Blank: Medium

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled arnount of doxycycline (C₂₂H₂₄N₂O₈) dissolved:

Result = (A_U/A_S) x (C_S/L) x Vx100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

CS = concentration of doxycycline 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 doxycycline (C₂₂H₂₄N₂O₈) is dissolved.

UNIFORMITY OF DOSAGE UNITS (905); Meet the requirements

4 IMPURITIES

ORGANIC IMPURITIES

Protect solutions containing doxycycline from light.

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

System suitability stock solution 1: 1 mg/mL each of USP Doxycycline Related Compound A RS and USP Methacycline Hydrochloride RS in Diluent

System suitability stock solution 2: 1.2 mg/mL of USP Doxycycline Hyclate RS in Diluent

System suitability solution: Transfer 5 mL of System suitability stock solution 2 to a 25-ml volumetric flask, heat on a steam bath for 60 min, and evaporate to dryness on a hot plate, taking care not to char the residue. Dissolve the residue in Diluent, add 0.5 ml. of Systern suitability stock solution 1, and dilute with Diluent to volume. Pass the solution through a suitable filter and use the filtrate. This solution contains a mixture of 4-epidoxycycline, doxycycline related compound A, methacycline, and doxycycline. [Nort-The solution is stable up to 14 days when stored in a refrigerator.]

Sensitivity solution: 2 µg/mL of USP Doxycycline Hyclate RS in Diluent

Standard solution: 4.6 µg/ml, of USP Doxycycline Hyclate RS in Diluent

Sample solution: Nominally 2.0 mg/ml of doxycycline from NLT 20 Tablets prepared as follows. Transfer a suitable portion of finely

powdered Tablets to a suitable volumetric flask. Add 80% of the final volume of Diluent, sonicate for about 15 min, shake for about 15 min,

and dilute with Diluent to volume. Pass through a suitable filter of 0.2-um pore size and use the filtrate for analysis.

System suitability

Samples: System suitability solution, Sensitivity solution, and Standard solution

Suitability requirements

Resolution: NLT 1.5 between methacycline and 4-epidoxycycline; NLT 1.5 between 4-epidoxycycline and doxycycline related compound A

NLT 2.0 between doxycycline related compound A and doxycycline, System suitability solution

Relative standard deviation: NMT 5.0% for the doxycycline peak, Standard solution

Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

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

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

r_U = peak response of each impurity from the Sample solution

r_S = peak response of doxycycline from the Standard solution

C_S = concentration of USP Doxycycline Hyclate RS, in the Stardard solution (mg/ml)

C_U = nominal concentration of doxycycline in the Sample sulation (mg/ml)

P = potency of doxycycline in USP Doxycycline Hyclate RS (µg/mg)

F = conversion factor 0.001 mg/μg

Acceptance criteria: See Table 8. The reporting threshold is 0.1%.

^a (4S,4aR,55,5aR, 12aS)-4-(Dimethylamino)-1,4,4,5,58,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methylene-1,11-dioxo-2-naphthacenecarboxamide.

^b (4R,4aR,55,5aR,6,12aS)-4-(Dimethylamino)-1,4,4,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-2-naphthacenecarboxamide.

^c(4R,4aR,5S,5aR,6R,12aS)-4-(Dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-2- naphthacenecarboxamide.

^d (4S,4aR,5S,5aR,6S,12aS)-4-(Dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-2 naphthacenecarboxamide.

^e (4S,4aR,5S,5aR,6S,12aS)-4-(Dimethylamino)-1,4,4,5,5,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-2- naphthacenecarboxamide.

5 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight, light-resistant containers. Store at controlled room temperature

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