Clindamycin Hydrochloride Oral Solution
Clindamycin Hydrochloride Oral Solution contains the equivalent of NLT 90.0% and NMT 110.0% of the labeled amount of clindamycin (C18H33ClN2O5S).
•  A. The retention time of the clindamycin peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
•  Procedure
Buffer:  6.8 g/L of monobasic potassium phosphate in water. Adjust with 8 N potassium hydroxide to a pH of 7.5.
Mobile phase:  Acetonitrile and Buffer (450:550). Increasing the proportion of acetonitrile in the Mobile phase decreases the retention time, and decreasing it increases the resolution between 7-epiclindamycin and clindamycin.
Standard solution:  1 mg/mL of USP Clindamycin Hydrochloride RS in Mobile phase
Sample solution:  Equivalent to 0.85 mg/mL of clindamycin from Oral Solution in Mobile phase
Chromatographic system 
Mode:  LC
Detector:  UV 210 nm
Column:  4.6-mm × 25-cm; 5-µm packing L1
Flow rate:  1 mL/min
Injection size:  10 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Resolution:  NLT 2.4 between the clindamycin B and 7-epiclindamycin peaks, and NLT 3.0 between the 7-epiclindamycin and clindamycin peaks
Column efficiency:  NLT 4000 theoretical plates from the clindamycin peak
Tailing factor:  NMT 1.2 for the clindamycin peak
Relative standard deviation:  NMT 1.0% for the clindamycin peak
Samples:  Standard solution and Sample solution
Calculate the percentage of clindamycin (C18H33ClN2O5S) in each mL of Oral Solution taken:
Result = (rU/rS) × (CS/CU) × P × F × 100
rU== peak area response from the Sample solution
rS== peak area response from the Standard solution
CS== concentration of USP Clindamycin Hydrochloride RS in the Standard solution (mg/mL)
CU== nominal concentration of clindamycin in the Sample solution (mg/mL)
P== potency of clindamycin in USP Clindamycin Hydrochloride RS (µg/mg)
F== conversion factor, 0.001 mg/µg
Acceptance criteria:  90.0%–110.0%
•  Uniformity of Dosage Units 905: Meets the requirements for solution packaged in single-unit containers
•  Deliverable Volume 698: Meets the requirements
•  pH 791: 2.5–6.0
•  Packaging and Storage: Preserve in tight containers.
•  Labeling: Label Oral Solution to indicate that it is intended for veterinary use only.
•  USP Reference Standards 11
USP Clindamycin Hydrochloride RS Click to View Structure
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
(SM12010) Monographs - Small Molecules 1
Reference Standards RS Technical Services
USP35–NF30 Page 2704
Pharmacopeial Forum: Volume No. 31(5) Page 1350