Doxycycline Hyclate Tablets
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
1 DEFINITION
Doxycycline Hyclate Tablets contain the equivalent of 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. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197A
Standard solution: Transfer about 25 mg of USP Doxycycline Hyclate RS to a suitable flask. Add 25 mL of acetonitrile and mix for approximately 5 min with a magnetic stir bar. Pass the solution through a suitable filter, and remove the solvent by natural evaporation or by using a rotary evaporator under vacuum.
Sample solution: Transfer powdered Tablets (NLT 25), equivalent to 25 mg of doxycycline hyclate, to a suitable flask. Add 25 mL of acetonitrile and mix for approximately 5 min with a magnetic stir bar. Pass the solution through a suitable filter, and remove the solvent by natural evaporation or by using a rotary evaporator under vacuum.
Analysis: Examine the spectra of the Standard solution and the Sample solution in the range between 2000 and 650c * m ^ - 1
Acceptance criteria: The Sample solution exhibits bands at about 1663, 1611, 1576, 1453, 1213, 1037, 1002, 935, and 659c * m ^ - 1 similar to the Standard solution.
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 triethylaming 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 ± 0.2.
Solution B: Methanol
Mobile phase: See Table 1.
| Time (min) | Solution A (%) | Solution B (%) |
| 0.0 | 90 | 10 |
| 2.0 | 90 | 10 |
| 4.0 | 60 | 40 |
| 6.0 | 90 | 10 |
| 9.0 | 90 | 10 |
Diluent: 0.01 N hydrochloric acid
System suitability stock solution 1: 1 mg/ml. each of LISP 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. When stored in a refrigerator, this solution may be used for 14 days.
Standard solution: 0.3 mg/ml of USP Doxycycline Hyclate RS in Diluent. Sonicate as needed to dissolve
Sample solution: Nominally 0.25 mg/ml of doxycycline in Diluent, prepared as follows. Transfer a suitable portion of NLT 20 finely powdered Tablets to a suitable volumetric flask. Add 50% of the final volume of Diluent, sonicate for about 5 min, shake for about 15 min, and dilute with Diluent to volume. Pass a portion of this solution through a suitable filter of 0.2-um pore size
Chromatographic system
(See Chromatography (621) System Suitability.)
Mode: LC
Detector: UV 350 nm
Column: 2.1-mm x 5-cm, 1.7-um packing (Nors-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
Samples: System suitability solution and Standard solution
NOTE-See Table 2 for relative retention times
Suitability requirements
Resolution: NLT 1.5 between methacycline and 4-epidoxycycline; NLT 1.5 between 4-epidoxycycline and doxycycline related compound A; NLT 1.5 between doxycycline related compound A and doxycycline, System suitability solution
Tailing factor: NMT 1.5, Standard solution
Relative standard deviation: NMT 2.0%, Standard solution
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of doxycycline (CH, NO) in the portion of Tablets taken:
Result = (rU/(rS) × (CS /CU) × P x F x 100
rU = peak response from the Sample solution
rS = peak response from the Standard solution
CS = concentration of USP Doxycycline Hyclate RS, in the Stardard solution (mg/ml)
CU = 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
Change to read:
DISSOLUTION (711)
Protect solutions containing doxycycline from light
Test 1
Medium: Water, 900 ml
Apparatus 2: 75 rpm, the distance between the blade and the inside bottom of the vessel being maintained at 4.5 +0.5 cm during the test
Time: 90 min
Standard solution: USP Doxycycline Hyclate RS in Medium
Sample solution: Dilute with Mediurn, if necessary, to a concentration that is similar to the Standard solution.
Instrumental conditions
(See Ultraviolet-Visible Spectroscopy (857)
Mode: UV-Vis
Analytical wavelength: 276 nm
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of doxycycline (C22H24N2O8) dissolved:
Result = (AU/AS) x (CS/L) x Vx100
AU = absorbance of the Sample solution
AS = 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 85% (Q) of the labeled amount of doxycycline ((C22H24N2O8) is dissolved.
Test 2: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2
Medium: Water, 900 mL
Apparatus 2: 50 rpm, the distance between the blade and the inside bottom of the vessel being maintained at 4.5 ± 0.5 cm during the test
Time: 30 min
Standard solution: 22 µg/mL of doxycycline from USP. Doxycycline Hyclate RS, in Medium
Sample solution: Pass a portion of the solution under test through a suitable filter.
Blank: Medium
Instrumental conditions
(See Ultraviolet-Visible Spectroscopy (857))
Mode: UV-Vis
Analytical wavelength: 276 nm
Cell: 0:5 cm
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of doxycycline (C22H24N2O8) dissolved:
Result = (AU/AS) x (CS/L) x V x 100
AU = absorbance of the Sample solution
AS = 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 85% (Q) of the labeled amount of doxycycline is dissolved.
Test 3: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 3.
Protect solutions containing doxycycline from light.
Medium: Water; 900 mL
Apparatus 2: 75 rpm
Time: 30 min
Standard solution: 0.016 mg/mL of doxycycline from USP Doxycycline Hyclate RS, in Medium. Sonicate, if necessary, in a cool water bath.
Sample solution: Pass a portion of the solution under test through a suitable lter of 0.45-μm pore size, and dilute with Medium, to a
concentration that is similar to the Standard solution.
Instrumental conditions
(See Ultraviolet-Visible Spectroscopy 〈857〉.)
Mode: UV-Vis
Analytical wavelength: 276 nm
Blank: Medium
Analysis
Samples: Standard solution and Sample solution
Samples: Standard solution and Sample solution Calculate the percentage of the labeled amount of doxycycline (C H N O ) dissolved:
Calculate the percentage of the labeled amount of doxycycline (C22H24N2O8) dissolved:
Result = (AU/AS) x (CS/L) x D x V x 100
AU = absorbance of the Sample solution
AS = absorbance of the Standard solution
CS = concentration of doxycycline in the Standard solution (mg/mL)
L = label claim (mg/Tablet)
D = dilution factor for the Sample solution
V = volume of Medium, 900 mL
Tolerances: NLT 80% (Q) of the labeled amount of doxycycline (C22H24N2O8) is dissolved.
Test 4: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 4 Protect solutions containing doxycycline from light.
Medium: Water: 900 mL
Apparatus 1: 100 грт
Time: 30 min
Standard solution: 0.020 mg/ml, of doxycycline from USP Doxycycline Hyclate RS, in Medium
Sample solution: Pass a portion of the solution under test through a suitable filter, and dilute with Medium, to a concentration that is similar to the Standard solution
Instrumental conditions
(See Ultraviolet-Visible Spectroscopy(857))
Mode: UV-Vis
Analytical wavelength: 276 nm
Blank: Medium
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of doxycycline (C22H24N2O8) dissolved:
Result = (AU/AS) x (CS/L) x V x 100
AU = absorbance of the Sample solution
AS = 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 (CH, NO) is dissolved
Test 5: If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 5.
Protect all solutions containing doxycycline from light
Medium: 0.1. N hydrochloric acid: 500 mL, deaerated
Apparatus 1: 100 rpm
Time: 30 min
Standard solution: 0.016 mg/ml of doxycycline from USP Doxycycline Hyclate RS in Medium. Sonicate to dissolve if needed.
Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-um pore size. Discard the first 2 mL of the filtrate.
Dilute with Medium to a concentration that is similar to that of the Standard solution
Instrumental conditions
(See Ultraviolet-Visible Spectroscopy(857)
Mode: UV
Analytical wavelength: 268 nm
Blank: Medium
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of doxycycline (C22H24N2O8) dissolved:
Result = (AU/AS) x (CS/L) x Vx100
AU = absorbance of the Sample solution
AS = absorbance of the Standard solution
CS = concentration of doxycycline in the Standard solution (mg/mL)
D = dilution factor for the Sample solution
L = label claim (mg/Tablet)
V = volume of Medium, 900 mL
Tolerances: NLT 80% (Q) of the labeled amount of doxycycline (C,H, NO) is dissolved (Re 9-Nov-2022)
UNIFORMITY OF DOSAGE UNITS (905): Meet the requirements
5 IMPURITIES
ORGANIC IMPURITIES
Mobile phase, Diluent, System suitability solution, Sample solution, and Chromatographic system: Proceed as directed in the Assay.
Standard solution: 1.5mu*g / m * k of USP Doxycycline Hyciate RS in Diluent
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 1.5 between doxycycline related compound A and doxycycline, System suitability solution
Relative standard deviation: NMT 5.0% for the doxycycline peak, Standard solution
Analysis
Samples: Sample solution and Standard solution
Calculate the percentage of each impurity in the portion of Tablets taken
Result = (rU/(rS) × (CS /CU) × P x F x 100
rU = peak response of each impurity from the Sample solution
rS = peak response of each impurity from the Standard solution
CS = concentration of USP Doxycycline Hyclate RS, in the Stardard solution (mg/ml)
CU = 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 any impurity peaks less than 0.2%
| Name | Relative Retention Time | Acceptance Criteria, NMT (%) |
| Methacyclinea,b | 0.64 | - |
| 4-Epidoxycyclinec | 0.79 | 1.5 |
| Doxycycline related compound A (6-epidoxycycline)b,d | 0.88 | - |
| Doxycycline | 1.0 | - |
| Any individual unspecified impurity | - | 0.5 |
| Total impurities | - | 2.0 |
a Process impurities are controlled in the drug substance and are not to be reported here. They are not included in total impurities
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. Store at controlled room temperature.
Labeling: When more than one Dissolution test is given, the labeling states the Dissolution test used only if Test 1 is not used.

