Pilocarpine Hydrochloride Tablets
DEFINITION
Pilocarpine Hydrochloride Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of pilocarpine hydrochloride (C11H16N2O2·HCl).
IDENTIFICATION
•  The retention time of the major peak of the Sample solution corresponds to the major peak of the Standard solution, as obtained in the Assay.
ASSAY
•  Procedure
Solution A:  10 N sodium hydroxide, 85% phosphoric acid, triethylamine, and water (7:6:1:500). Adjust with 10 N sodium hydroxide to a pH of 3.0.
Mobile phase:  Methanol and Solution A (3:100)
Standard solution:  50 µg/mL of USP Pilocarpine Hydrochloride RS
System suitability solution:  Transfer 10 mL of the Standard solution to a test tube. Add 100 µL of 2 N sodium hydroxide, mix well, and allow it to stand for 5 min. Add 100 µL of 2 N hydrochloric acid and mix well. [note—This preparation contains pilocarpine, isopilocarpine, and two unidentified compounds. ]
Sample stock solution:  Place Tablets, equivalent to 50 mg of pilocarpine hydrochloride, in a 500-mL volumetric flask. Fill the flask to 75% full with water. Stir for at least 30 min or more if necessary, until the tablets are completely disintegrated and the powder is finely dispersed. Dilute with water to volume.
Sample solution:  Transfer 5 mL of Sample stock solution to a 10-mL volumetric flask, and dilute with water to volume. Pass a suitable amount of solution through a PVDF, 0.45-µm pore size filter, and discard first 5 mL.
Chromatographic system 
Mode:  LC
Detector:  UV 215 nm
Column:  4.6-mm × 15-cm; 5-µm packing L1
Flow rate:  1.5 mL/min
Injection size:  20 µL
System suitability 
Samples:  Standard solution and System suitability solution
[Note—The relative retention times for isopilocarpine, pilocarpine, and two unidentified peaks are 0.9, 1.0, 1.2, and 1.5, respectively. ]
Suitability requirements 
Resolution:  NLT 1.2 between isopilocarpine and pilocarpine; NLT 1.2 between pilocarpine and the peak at a relative retention time of 1.2; NLT 1.2 between peaks at relative retention times of 1.2 and 1.5, System suitability solution
Column efficiency:  NLT 1500 theoretical plates, Standard 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 C11H16N2O2·HCl in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response of pilocarpine hydrochloride from the Sample solution
rS== peak response of pilocarpine hydrochloride from the Standard solution
CS== concentration of USP Pilocarpine Hydrochloride RS in the Standard solution (mg/mL)
CU== nominal concentration of pilocarpine hydrochloride in the Sample solution (mg/mL)
Acceptance criteria:  90.0%–110.0%
PERFORMANCE TESTS
•  Dissolution 711
Medium:  0.1 N hydrochloric acid; 500 mL
Apparatus 2:  50 rpm
Time:  45 min
Buffer solution:  13.5 mL of phosphoric acid and 3.0 mL of triethylamine in 1000 mL of water. Adjust with phosphoric acid or 10 N sodium hydroxide to a pH of 3.
Mobile phase:  Methanol and Buffer solution (3:17)
Standard stock solution:  0.1 mg/mL of USP Pilocarpine Hydrochloride RS in Medium
Standard solution:  For Tablets labeled to contain 7.5 mg, transfer 15.0 mL of the Standard stock solution to a 100-mL volumetric flask, and dilute with Medium to volume. For Tablets labeled to contain 5 mg, transfer 5.0 mL of the Standard stock solution to a 50-mL volumetric flask, and dilute with Medium to volume.
Sample solution:  Pass the solution under test through a suitable, 45-µm pore size polyethylene filter.
Chromatographic system 
Mode:  LC
Detector:  UV 215 nm
Column:  4.6-mm × 15-cm; packing L1
Flow rate:  1 mL/min
Injection size:  20 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Column efficiency:  NLT 1500 theoretical plates
Tailing factor:  NMT 2.0
Relative standard deviation:  NMT 2.0%
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of pilocarpine hydrochloride dissolved:
Result = (rU/rS) × (CS/L) × V × 100
rU== peak response from the Sample solution
rS== peak response from the Standard solution
CS== concentration of the Standard solution (mg/mL)
L== Tablet label claim (mg)
V== volume of Medium, 500 mL
Tolerances:  NLT 75% (Q) of the labeled amount of pilocarpine hydrochloride is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements
Procedure for content uniformity 
Mobile phase, Standard solution, System suitability solution, Chromatographic system, and System suitability:  Proceed as directed in the Assay.
Sample solution:  Place 1 Tablet in a suitable volumetric flask, fill the flask about 75% full with water, and vigorously stir for NLT 30 min to ensure complete disintegration. Dilute with water to volume to obtain a final concentration of 0.05 mg/mL of pilocarpine hydrochloride. Pass the solution through a PVDF, 0.45-µm pore size filter.
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of C11H16N2O2·HCl in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response of pilocarpine hydrochloride from the Sample solution
rS== peak response of pilocarpine hydrochloride from the Standard solution
CS== concentration of USP Pilocarpine Hydrochloride RS in the Standard solution (mg/mL)
CU== nominal concentration of pilocarpine hydrochloride in the Sample solution (mg/mL)
IMPURITIES
Organic Impurities 
•  Procedure
Mobile phase, System suitability solution, and System suitability:  Proceed as directed in the Assay.
Standard solution:  0.5 µg/mL of USP Pilocarpine Hydrochloride RS
Sample solution:  Pass a suitable amount of Sample stock solution, prepared as directed in the Assay, through a PVDF, 0.45-µm pore size filter, and use the filtrate for analysis after discarding the first 5 mL.
Chromatographic system 
Mode:  LC
Detector:  UV 215 nm
Column:  4.6-mm × 15-cm; 5-µm packing L1
Flow rate:  1.5 mL/min
Injection size:  100 µL
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of each impurity in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × (1/F) × 100
rU== peak response of each impurity from the Sample solution
rS== peak response of pilocarpine hydrochloride from the Standard solution
CS== concentration of USP Pilocarpine Hydrochloride RS in the Standard solution (mg/mL)
CU== nominal concentration of pilocarpine hydrochloride in the Sample solution (mg/mL)
F== relative response factor for each impurity (see Impurity Table 1)
Acceptance criteria 
Individual impurities:  See Impurity Table 1.
Total impurities:  NMT 1.2%
Impurity Table 1
Name Relative
Retention
Time
Relative
Response
Factor
Acceptance
Criteria,
NMT (%)
Isopilocarpine 0.9 0.79 1.0
Pilocarpine 1.0 1.0
Pilocarpic acid 1.2 1.0 0.5
Individual unspecified degradation product 1.0 0.2
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.
•  USP Reference Standards 11
USP Pilocarpine Hydrochloride RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
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(SM32010) Monographs - Small Molecules 3
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USP35–NF30 Page 4323
Pharmacopeial Forum: Volume No. 34(2) Page 291