Clindamycin Hydrochloride
(klin'' da mye' sin hye'' droe klor' ide).
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C18H33ClN2O5S·HCl 461.45
C18H33ClN2O5S·HCl·H2O 479.47
l-threo--d-galacto-Octopyranoside, methyl 7-chloro-6,7,8-trideoxy-6-[[(1-methyl-4-propyl-2-pyrrolidinyl)-carbonyl]amino]-1-thio-, (2S-trans)-, monohydrochloride;    
Methyl 7-chloro-6,7,8-trideoxy-6-(1-methyl-trans-4-propyl-l-2-pyrrolidinecarboxamido)-1-thio-l-threo--d-galacto-octopyranoside monohydrochloride     [21462-39-5].
Monohydrate     [58207-19-5].
DEFINITION
Clindamycin Hydrochloride is the hydrated hydrochloride salt of clindamycin, a substance produced by the chlorination of lincomycin. It has a potency equivalent to NLT 800 µg/mg of C18H33ClN2O5S.
IDENTIFICATION
Change to read:
•  A.USP35 Infrared Absorption 197M
Add the following:
•  B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.USP35
ASSAY
Change to read:
•  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 (9:11) USP35
Standard solution:  1 mg/mL of USP Clindamycin Hydrochloride RS in Mobile phase
Sample solution:  1 mg/mL of Clindamycin Hydrochloride 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 
[Note—USP Clindamycin Hydrochloride RS contains clindamycin B and 7-epiclindamycin as minor components. ]
USP35
Resolution:  NLT 2.4 between clindamycin B and 7-epiclindamycin and NLT 3.0 between 7-epiclindamycin and clindamycin
USP35
Tailing factor:  NMT 1.2 for the clindamycin peak
Relative standard deviation:  NMT 1.0% for the clindamycin peak
Analysis 
Samples:  Standard solution and Sample solution
Record the chromatograms for a period of time that is twice the retention time of the clindamycin peak.
Calculate the potency of C18H33ClN2O5S, in µg/mg, in the portion of Clindamycin Hydrochloride taken:
Result = (rU/rS) × (CS/CU) × P
rU== peak area from the Sample solution
rS== peak area from the Standard solution
CS== concentration of USP Clindamycin Hydrochloride RS in the Standard solution (mg/mL)
CU== concentration of Clindamycin Hydrochloride in the Sample solution (mg/mL)
P== potency of clindamycin in USP Clindamycin Hydrochloride RS (µg/mg)
Acceptance criteria:  NLT 800 µg/mg
IMPURITIES
Organic Impurities 
•  Procedure
Buffer and Mobile phase:  Prepare as directed in the Assay.
Standard stock solution:  0.5 mg/mL of USP Lincomycin Hydrochloride RS and 1 mg/mL of USP Clindamycin Hydrochloride RS in Mobile phase
Standard solution:  50 µg/mL of USP Lincomycin Hydrochloride RS and 100 µg/mL of USP Clindamycin Hydrochloride RS from Standard stock solution in Mobile phase
Sample solution:  5 mg/mL of Clindamycin Hydrochloride 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
Analysis 
Samples:  Standard solution and Sample solution
Record the chromatograms for a period of time that is six times the retention time of clindamycin.
Calculate the percentage of lincomycin in the portion of Clindamycin Hydrochloride taken:
Result = (rU/rS) × (CS/CU) × P × F × 100
rU== peak response of lincomycin from the Sample solution
rS== peak response of lincomycin from the Standard solution
CS== concentration of USP Lincomycin Hydrochloride RS in the Standard solution (mg/mL)
CU== concentration of Clindamycin Hydrochloride in the Sample solution (mg/mL)
P== potency of USP Lincomycin RS (µg/mg)
F== conversion factor, 0.001 mg/µg
Calculate the percentage of all other related compounds in the portion of Clindamycin Hydrochloride taken:
Result = (rU/rS) × (CS/CU) × P × F × 100
rU== peak response of each individual related compound, other than lincomycin, from the Sample solution
rS== peak response of clindamycin from the Standard solution
CS== concentration of USP Clindamycin Hydrochloride RS in the Standard solution (mg/mL)
CU== concentration of the Sample solution (mg/mL)
P== potency of USP Clindamycin Hydrochloride RS (µg/mg)
F== conversion factor, 0.001 mg/µg
Acceptance criteria:  See Table 1.
Table 1
Name Relative
Retention
Time
Acceptance
Criteria,
NMT (%)
Lincomycina 0.4
Clindamycin B 0.65 2.0
7-Epiclindamycin 0.8 4.0
Clindamycin 1.0
Any other individual
related compound
1.0
Total related
compoundsb
6.0
a  Lincomycin is controlled in the total of all related compounds. There is no individual acceptance criterion for this compound.
b  Total of all related compounds including lincomycin.
SPECIFIC TESTS
•  Crystallinity 695: Meets the requirements
•  pH 791: 3.0–5.5, in a 100-mg/mL solution
•  Water Determination, Method I 921: 3.0%–6.0%
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight containers.
•  USP Reference Standards 11
USP Clindamycin Hydrochloride RS Click to View Structure
l-threo--d-galacto-Octopyranoside, methyl 7-chloro-6,7,8-trideoxy-6-[[(1-methyl-4-propyl-2-pyrrolidinyl)-carbonyl]amino]-1-thio-, (2S-trans)-, monohydrochloride.
    C18H33ClN2O5S·HCl        461.45
USP Lincomycin Hydrochloride RS Click to View Structure
d-erythro--d-galacto-Octopyranoside, methyl 6,8-dideoxy-6-[[(1-methyl-4-propyl-2-pyrrolidinyl)carbonyl]amino]-1-thio-, monohydrochloride, monohydrate, (2S-trans)-.
    C18H34N2O6S·HCl·H2O        461.02
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USP35–NF30 Page 2702
Pharmacopeial Forum: Volume No. 36(6) Page 1520