Balsalazide Disodium Capsules
DEFINITION
Balsalazide Disodium Capsules contain NLT 90.0% and NMT 110.0% of the labeled amount of balsalazide disodium (C17H13N3Na2O6·2H2O).
IDENTIFICATION
•  A. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
•  B. Ultraviolet Absorption
Using a 0.2-cm cell, record the UV spectrum of the Sample solution, obtained in the Assay, in the range of 200–400 nm: it exhibits maxima at about 261 nm and 357 nm.
ASSAY
•  Procedure
Buffer:  Add 5 mL of triethylamine to 1000 mL of water, and adjust with phosphoric acid to a pH of 6.00 ± 0.1.
Mobile phase:  Acetonitrile and Buffer (1:4)
Diluent:  Water
Standard solution:  60 µg/mL of USP Balsalazide Disodium RS in Diluent. [Note—Use sonication as necessary. ]
Sample stock solution:  Transfer an equivalent to 150 mg of balsalazide disodium, from the Capsules contents, to a 100-mL volumetric flask, add 70 mL of Diluent, sonicate for 5 min, and dilute with Diluent to volume.
Sample solution:  60 µg/mL of balsalazide disodium, from the Sample stock solution, in Diluent. Pass a portion of this solution through a suitable filter, discarding the first 3 mL.
Chromatographic system 
Mode:  LC
Detector:  UV 360 nm
Column:  4.6-mm × 25-cm; 5-µm packing L1
Column temperature:  30
Flow rate:  1 mL/min
Injection size:  10 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Column efficiency:  NLT 10,000 theoretical plates
Tailing factor:  NMT 2.0
Relative standard deviation:  NMT 2.0%
Analysis 
Sample:  Standard solution and Sample solution
Calculate the percentage of the labeled amount of C17H13N3Na2O6·2H2O in the portion of Capsules taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response from the Sample solution
rS== peak response from the Standard solution
CS== concentration of USP Balsalazide Disodium RS in the Standard solution (mg/mL)
CU== nominal concentration of balsalazide disodium in the Sample solution (mg/mL)
Acceptance criteria:  90.0%–110.0%
IMPURITIES
Organic Impurities 
•  Procedure
Buffer:  Dissolve 2.7 g of monobasic potassium phosphate in 1000 mL of water, and adjust with 10% potassium hydroxide solution to a pH of 6.00 ± 0.1.
Diluent:  Water
Solution A:  Buffer
Solution B:  Acetonitrile
Sample solution:  Transfer an amount of finely crushed powder equivalent to 100 mg of balsalazide disodium to a 100-mL volumetric flask, add 70 mL of Diluent, sonicate for 5 min, and dilute with Diluent to volume. Pass a portion of this solution through a PVDF filter of 0.45-µm pore size.
Standard solution:  1.0 µg/mL of USP Balsalazide Disodium RS in Diluent
System suitability solution:  1.0 µg/mL of USP Balsalazide Disodium RS, 1.5 µg/mL of USP Balsalazide Related Compound A RS, 0.5 µg/mL of USP Balsalazide Related Compound B RS, and 0.5 µg/mL of USP Salicylic Acid RS in Diluent
Mobile phase:  See the gradient table below.
Time
(min)
Solution A
(%)
Solution B
(%)
0 90 10
4 90 10
40 75 25
47 75 25
55 50 50
60 50 50
60.1 90 10
70 90 10
Chromatographic system 
Mode:  LC
Detector:  UV 238 nm
Column:  4.6-mm × 25-cm; 5-µm packing L1
Column temperature:  45
Flow rate:  1 mL/min
Injection size:  30 µL
System suitability 
Samples:  Standard solution and System suitability solution
Suitability requirements 
Resolution:  NLT 5 between balsalazide and balsalazide related compound B, System suitability solution
Relative standard deviation:  NMT 5.0%, Standard solution
Tailing factor:  NMT 1.5, Standard solution
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of each impurity in the portion of Capsules taken:
Result = (rU/rS) × (CS/CU) × (1/F)× 100
rU== peak response for each individual impurity from the Sample solution
rS== peak response for the balsalazide peak from the Standard solution
CS== concentration of USP Balsalazide Disodium RS in the Standard solution (mg/mL)
CU== nominal concentration of balsalazide disodium in the Sample solution, based on the label claim (mg/mL)
F== relative response factor (see Impurity Table 1)
Acceptance criteria 
Individual impurities:  See Impurity Table 1.
Reporting level for impurities:  0.05%
Total impurities:  NMT 1.0%. [Note—When reporting results for Individual impurities and Total impurities, disregard peaks corresponding to salicylic acid and balsalazide related compound B, as these impurities are controlled in the drug substance only. ]
Impurity Table 1
Name Relative
Retention
Time
Relative
Response
Factor
Acceptance
Criteria,
NMT (%)
Salicylic acid 0.37
Balsalazide related compound Aa 0.70 1.3 0.15
Balsalazide 1.00
Balsalazide related compound Bb 1.2
Any other individual
unspecified impurity
1.0 0.10
a  (E)-5-[(p-Carboxyphenyl)azo]-2-salicylic acid.
b  (E)-5-({m-[(2-Carboxyethyl)carbamoyl]phenyl}azo)-2-salicylic acid.
PERFORMANCE TESTS
•  Dissolution 711
Medium:  pH 6.8 phosphate buffer; 900 mL
Apparatus 2:  50 rpm, with stainless steel wire helix sinkers
Time:  30 min
Detector:  UV 357 nm, with background correction at 590 nm
Path length:  0.02-cm flow cell
Blank:  Medium
Standard solution:  0.83 mg/mL of USP Balsalazide Disodium RS in Medium
Sample solution:  Pass a portion of the solution under test through a suitable filter of 20-µm pore size.
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of C17H13N3Na2O6·2H2O dissolved:
Result = (AU/AS) × CS × V × (100/L)
AU== absorbance of the Sample solution
AS== absorbance of the Standard solution
CS== concentration of USP Balsalazide Disodium RS in the Standard solution (mg/mL)
V== volume of Medium (mL), 900
L== Capsule label claim (mg)
Tolerances:  NLT 70% (Q) of the labeled amount of C17H13N3Na2O6·2H2O is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.
•  USP Reference Standards 11
USP Balsalazide Disodium RS Click to View Structure
USP Balsalazide Related Compound A RS
(E)-5-[(p-Carboxyphenyl)azo]-2-salicylic acid, disodium salt.
    C14H8N2O5Na2         330.12
USP Balsalazide Related Compound B RS
(E)-5-({m-[(2-Carboxyethyl)carbamoyl]phenyl}azo)-2-salicylic acid.
    C17H15N3O6          357.17
USP Salicylic Acid RS Click to View Structure
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Topic/Question Contact Expert Committee
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Principal Scientific Liaison
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