Doxycycline Hyclate Tablets
DEFINITION
Doxycycline Hyclate Tablets contain the equivalent of NLT 90.0% and NMT 120.0% of the labeled amount of doxycycline (C22H24N2O8).
IDENTIFICATION
• Procedure
Sample solution:
Shake a suitable quantity of finely ground Tablets with methanol to obtain a solution containing the equivalent of 1 mg/mL of doxycycline, and filter. Use the filtrate as the Sample solution.
Analysis:
Proceed as directed under Identification—Tetracyclines 
193
, Method II.
193, Method II.
ASSAY
• Procedure
Mobile phase:
Transfer 2.72 g of monobasic potassium phosphate, 0.74 g of sodium hydroxide, 0.50 g of tetrabutylammonium hydrogen sulfate, and 0.40 g of edetate disodium to a 1000-mL volumetric flask. Add 850 mL of water, and stir to dissolve. Add 60 g of tertiary butyl alcohol with the aid of water, dilute with water to volume, and adjust with 1 N sodium hydroxide to a pH of 8.0 ± 0.1. Decreasing the proportion of tertiary butyl alcohol results in a longer retention time of doxycycline and improved separation of doxycycline from the related compounds.
Diluent:
0.01 N hydrochloric acid
[Note—Throughout the following sections, protect the Standard solution and the Sample solution from light. ]
Standard solution:
1.2 mg/mL of USP Doxycycline Hyclate RS in Diluent. [Note—Sonicate as necessary to dissolve. ]
System suitability solution:
Prepare 6 mg/mL of doxycycline from USP Doxycycline Hyclate RS in Diluent. Transfer 5 mL of this solution 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 0.01 N hydrochloric acid, dilute with Diluent to volume, and filter. This solution contains a mixture of 4-epidoxycycline, 6-epidoxycycline, and doxycycline. When stored in a refrigerator, this solution may be used for 14 days.
Sample solution:
Transfer an equivalent to 100 mg of doxycycline, from finely powdered Tablets (NLT 20), to a 100-mL volumetric flask, add 75 mL of Diluent, sonicate for 5 min, shake for 15 min, dilute with Diluent to volume, and mix. Pass through a suitable filter.
Chromatographic system
Mode:
LC
Detector:
UV 270 nm
Column:
4.6-mm × 25-cm; packing L21
Column temperature:
60 ± 1
Flow rate:
1 mL/min
Injection size:
20 µL
System suitability
Samples:
Standard solution and System suitability solution
[Note—The relative retention times for 4-epidoxycycline (the main degradation product), 6-epidoxycycline, and doxycycline are about 0.4, 0.7, and 1.0, respectively, System suitability solution. ]
Suitability requirements
Resolution:
NLT 3.0 between the 4-epidoxycycline peak and the doxycycline peak, System suitability solution
Tailing factor:
NMT 2.0, System suitability solution
Relative standard deviation:
NMT 2.0%, Standard solution is dissolved.
Analysis
Samples:
Standard solution and Sample solution
Record the chromatograms for a period of time that is 1.7 times the retention time of doxycycline.
Calculate the percentage of C22H24N2O8 in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × (P/1000) × 100
| rU | = | = peak response from the Sample solution |
| rS | = | = peak response from the Standard solution |
| CS | = | = concentration of USP Doxycycline Hyclate RS in the Standard solution (mg/mL) |
| CU | = | = nominal concentration of doxycycline in the Sample solution (mg/mL) |
| P | = | = potency of doxycycline, converted from µg/mg to mg/mg |
Acceptance criteria:
90.0%–120.0%
PERFORMANCE TESTS
• Dissolution 711
[Note—Use low-actinic glassware to prepare the solutions. ]
711
[Note—Use low-actinic glassware to prepare the solutions. ]
Test 1
Medium:
Water; 900 mL
Apparatus 2:
75 rpm, the distance between the blade and the inside bottom of the flask 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 Medium, if necessary, to a concentration that is similar to the Standard solution.
Spectrometric conditions
Mode:
UV-Vis
Analytical wavelength:
276 nm
Tolerances:
NLT 85% (Q) of the labeled amount of 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 in Medium, prepared using USP Doxycycline Hyclate RS
Sample solution:
Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size.
Spectrometric conditions
Mode:
UV-Vis
Analytical wavelength:
276 nm
Cell:
0.5 cm
Blank:
Medium
Calculate the percentage of doxycycline dissolved in the portion of Tablets taken:
Result = (AU/AS) × (CS/L) × V × 100
| AU | = | = absorbance of the Sample solution |
| AS | = | = absorbance of the Standard solution |
| CS | = | = concentration of doxycyline in the Standard solution (mg/mL) |
| L | = | = Tablet label claim (mg) |
| V | = | = volume of Medium, 900 mL |
Tolerances:
NLT 85% (Q) of the labeled amount of doxycycline is dissolved.
• Uniformity of Dosage Units 905:
Meet the requirements
905:
Meet the requirements
SPECIFIC TESTS
• Water Determination, Method I 921:
NMT 5.0%
921:
NMT 5.0%
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight, light-resistant containers.
• Labeling:
When more than one Dissolution test is given, the labeling states the Dissolution test used only if Test 1 is not used.
• USP Reference Standards 11
11
USP Doxycycline Hyclate RS 
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Ahalya Wise, M.S.
Senior Scientific Liaison 1-301-816-8161 |
(SM12010) Monographs - Small Molecules 1 |
| 711 |
Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison 1-301-816-8106 |
(GCDF2010) General Chapters - Dosage Forms |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2987