Olopatadine Hydrochloride Ophthalmic Solution
DEFINITION
Olopatadine Hydrochloride Ophthalmic Solution is a sterile aqueous solution of Olopatadine Hydrochloride. It contains NLT 90.0% and NMT 110.0% of the labeled amount of olopatadine (C21H23NO3). It may contain suitable antimicrobial agents.
IDENTIFICATION
•  The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
ASSAY
•  Procedure
[Note—Protect solutions from light. ]
Buffer:  Dissolve 13.6 g of monobasic potassium phosphate in 1 L of water, add 1 mL of triethylamine, and mix. Adjust with phosphoric acid to a pH of 3.0.
Mobile phase:  Acetonitrile and Buffer (7:18)
Standard solution:  0.1 mg/mL of USP Olopatadine Hydrochloride RS in Mobile phase
Sample solution:  Equivalent to 0.1 mg/mL of olopatadine in Mobile phase, from Olopatadine Hydrochloride Ophthalmic Solution
Chromatographic system 
Mode:  LC
Detector:  UV 299 nm
Column:  4.6-mm × 15-cm; 5-µm packing L7
Flow rate:  1 mL/min
Injection size:  30 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Column efficiency:  NLT 2000 theoretical plates
Tailing factor:  NMT 2.0
Relative standard deviation:  NMT 2.0%
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of C21H23NO3 in the portion of Ophthalmic Solution taken:
Result = (rU/rS) × (CS/CU) × (Mr1/Mr2) × 100
rU== peak response of the Sample solution
rS== peak response of the Standard solution
CS== concentration of olopatadine hydrochloride in the Standard solution (mg/mL)
CU== nominal concentration of olopatadine in the Sample solution (mg/mL)
Mr1== molecular weight of olopatadine, 337.41
Mr2== molecular weight of olopatadine hydrochloride, 373.87
Acceptance criteria:  90.0%–110.0%
IMPURITIES
Organic Impurities 
[Note—Protect solutions from light. ]
•  Procedure 1: Limit of Early Eluting Impurities
Mobile phase:  Proceed as directed in the Assay.
Blank solution:  Mobile phase
System suitability solution:  0.2 mg/mL of USP Olopatadine Hydrochloride RS and 0.02 mg/mL of USP Olopatadine Related Compound B RS in Mobile phase
Standard solution:  0.2 mg/mL of USP Olopatadine Hydrochloride RS in Mobile phase
Sample solution:  Equivalent to 0.2 mg/mL of olopatadine in Mobile phase, from Olopatadine Hydrochloride Ophthalmic Solution
Chromatographic system 
Mode:  LC
Detector:  UV 299 nm
Column:  4.6-mm × 15-cm; 5-µm packing L7
Flow rate:  1 mL/min
Injection size:  30 µL
Run time:  At least 1.6 times the retention time of the major peak
System suitability 
Samples:  System suitability solution and Standard solution
Suitability requirements 
Resolution:  NLT 2.0 between olopatadine and olopatadine related compound B, System suitability solution
Column efficiency:  NLT 2000 theoretical plates, Standard solution
Tailing factor:  NMT 2.0, Standard solution
Relative standard deviation:  NMT 2.0%, Standard solution
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of each impurity in the portion of Ophthalmic Solution taken:
Result = (rU/rS) × (CS/CU) × (Mr1/Mr2) × (1/F) × 100
rU== peak response of each impurity from the Sample solution
rS== peak response of olopatadine from the Standard solution
CS== concentration of olopatadine hydrochloride in the Standard solution (mg/mL)
CU== nominal concentration of olopatadine in the Sample solution (mg/mL)
Mr1== molecular weight of olopatadine, 337.41
Mr2== molecular weight of olopatadine hydrochloride, 373.87
F== relative response factor for each individual impurity (see Impurity Table 1)
[Note—Disregard any peaks corresponding to those of the Blank solution and any peaks with relative retention time, measured with respect to olopatadine, greater than 1.5. ]
Acceptance criteria 
Individual impurities:  See Impurity Table 1.
Impurity Table 1
Name Relative
Retention
Time
Relative
Response
Factor
Acceptance
Criteria,
NMT (%)
Olopatadine E-isomera 0.7 1.3 0.5
Olopatadine 1.0
Olopatadine related compound B 1.2 1.0 2
Olopatadine carbaldehydeb 1.3 4.5 0.5
Any unspecified impurity 1.0 0.5
a  11-[(E)-3-(Dimethylamino)propylidene]-6,11-dihydrodibenz[b,e]oxepin-2-acetic acid.
b  (Z)-11-[3-(dimethylamino)propylidene]-6,11-dihydrodibenzo[b,e]oxepine-2-carbaldehyde.
•  Procedure 2: Limit of Late Eluting Impurities
Buffer:  Proceed as directed in the Assay.
Mobile phase:  Acetonitrile and Buffer (1:1)
Blank solution:  Mobile phase
System suitability solution:  0.02 mg/mL of USP Olopatadine Hydrochloride RS and 0.01 mg/mL of USP Olopatadine Related Compound C RS in Mobile phase
Standard solution:  0.01 mg/mL of USP Olopatadine Related Compound C RS in Mobile phase
Sample solution:  Use the Sample solution from the test for Limit of Early Eluting Impurities.
Chromatographic system 
Mode:  LC
Detector:  UV 299 nm
Column:  4.6-mm × 15-cm; 5-µm packing L7
Flow rate:  1 mL/min
Injection size:  30 µL
Run time:  At least 3 times the retention time of the olopatadine related compound C peak
System suitability 
Samples:  System suitability solution and Standard solution
[Note—The relative retention times for olopatadine and olopatadine related compound C are 0.3 and 1.0, respectively. ]
Suitability requirements 
Resolution:  NLT 7.0 between olopatadine and olopatadine related compound C, System suitability solution
Column efficiency:  NLT 2000 theoretical plates, Standard solution
Tailing factor:  NMT 2.0, Standard solution
Relative standard deviation:  NMT 2.0%, Standard solution
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of each impurity in the portion of Ophthalmic Solution taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response of each impurity from the Sample solution
rS== peak response of olopatadine related compound C from the Standard solution
CS== concentration of USP Olopatadine Related Compound C RS in the Standard solution (mg/mL)
CU== nominal concentration of olopatadine in the Sample solution (mg/mL)
[Note—Disregard any peaks corresponding to those of the Blank solution and any peaks with a relative retention time, measured with respect to olopatadine related compound C, less than 0.7. ]
Acceptance criteria 
Individual impurities:  NMT 1% of olopatadine related compound C is found; and NMT 0.5% of any other individual impurity is found.
Total impurities:  NMT 3%. [Note—Total impurities are the sum of olopatadine related compound B, olopatadine related compound C, Olopatadine E-isomer, Olopatadine carbaldehyde, and all other impurities found in the tests for Limit of Early Eluting Impurities and Limit of Late Eluting Impurities. ]
SPECIFIC TESTS
•  Sterility Tests 71: Meets the requirements
•  pH 791: Between 5.0 and 8.0
•  Osmolality and Osmolarity 785: Between 260 and 320 mOsmol/kg
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight, light-resistant containers. Store between 4 and 25.
•  USP Reference Standards 11
USP Olopatadine Hydrochloride RS Click to View Structure
USP Olopatadine Hydrochloride Related Compound B RS
(Z)-3-{2-(Carboxymethyl)dibenzo[b,e]oxepin-11(6H)-ylidene}-N,N-dimethylpropan-1-amine oxide.
    C21H23NO4         353.41
USP Olopatadine Hydrochloride Related Compound C RS
11-Oxo-6,11-dihydrodibenzo[b,e]oxepin-2-yl acetic acid.
    C16H12O4        268.26
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