Doxycycline Capsules

1 DEFINITION

Doxycycline Capsules contain NLT 90.0% and NMT 120.0% of the labeled amount of doxycycline (C₂₂H₂₄N₂O₈).

2 IDENTIFICATION

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

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

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 ± 0.1.

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 in Diluent, prepared as follows. Transfer an adequate amount of doxycycline from the contents of NLT 20 Capsules to a suitable volumetric flask. Add 80% of the final volume of Diluent, sonicate for about 5 min, shake for about 15 min, and dilute with Diluent to volume. Centrifuge a portion of the solution for 10 min at 3000 rpm and use the supernatant for analysis.

Chromatographic system

(See Chromatography (621) System Suitability)

Mode: LC

Detector: UV 270 nm. For Identification A, a diode array detector may be used in the wavelength range of 200-400 nm.

Column: 2.1-mm x 5-cm; 1.7-um packing LZ. [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 Capsules 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%

4 PERFORMANCE TESTS

• Dissolution 〈711〉

Test 1

Medium: 0.01 N hydrochloric acid; 900 mL

Apparatus 2: 75 rpm

Time: 60 min

Standard solution: A known concentration of USP Doxycycline Hyclate RS in Medium

Sample solution: Filter a portion of the solution under test and dilute with Medium, if necessary.

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.)

Mode: UV

Analytical wavelength: Maximum absorbance at about 268 nm

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of doxycycline (C H N O ) dissolved:

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

AU = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

L = label claim (mg/Capsule)

V = volume of Medium, 900 mL

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

F = conversion factor, 0.001 mg/µg

Tolerances: NLT 85% (Q) of the labeled amount of doxycycline (C H N O ) is dissolved.

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

Medium: 0.01 N hydrochloric acid; 900 mL

Apparatus 2: 50 rpm, with sinkers

Time: 30 min

Standard solution: A known concentration of USP Doxycycline Hyclate RS in Medium

Sample solution: Filter a portion of the solution under test and dilute with Medium, if necessary.

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.)

Mode: UV

Analytical wavelength: 268 nm

Analysis

Samples: Standard solution and Sample solution

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

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

AU = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

L = label claim (mg/Capsule)

V = volume of Medium, 900 mL

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

F = conversion factor, 0.001 mg/µg

Tolerances: NLT 85% (Q) of the labeled amount of doxycycline (C H N O ) is dissolved

UNIFORMITY OF DOSAGE UNITS (905): Meet the requirements

5 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 System 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. [NOTE-The solution is stable up to 14 days when stored in a refrigerator at 2"-8"]

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

Sample solution: Nominally 2.0 mg/mL of doxycycline in Diluent, prepared as follows. Accurately weigh and transfer a portion of the composite equivalent to 100.0 mg of doxycycline to a 50-mL volumetric flask. Add 80% of the final volume of Diluent, sonicate for about 5 min, shake for about 15 min, and dilute with Diluent to volume. Centrifuge a portion of the solution for 10 min at 3000 rpm and use the supernatant for analysis.

System suitability

Samples: System suitability 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

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Capsules 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 2. Disregard peaks less than 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.

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.