Didanosine for Oral Solution

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION 

Didanosine for Oral Solution, when reconstituted as directed in the labeling, yields a 10 mg/mL solution that contains NLT 90.0% and NMT 110.0% of the labeled amount of didanosine (C₁₀H₁₂N₄O₃).

2 IDENTIFICATION 

Change to read: 

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K (CN 1-May-2020) 

B. The retention time of the major peak in the Sample solution corresponds to that of the Standard solution, as obtained in the Assay. 

3 ASSAY 

Change to read: 

3.1 Procedure 

Solution A: 0.77 mg/mL of ammonium acetate in water 

Mobile phase: Acetonitrile and Solution A (1:24) 

Standard solution: 0.1 mg/mL of USP Didanosine RS in water. [Note—Use this solution within 24 h of preparation.] Sample solution: 0.1 mg/mL obtained by diluting the contents of 1 bottle of Didanosine for Oral Solution in water. [Note—Use this solution within 24 h of preparation.] 

Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC 

Detector: UV 254 nm 

Analytical column: 4-mm × 25-cm; packing L1 

Guard column: 4.6-mm × 20-mm; (ERR 1-May-2018) packing L1 

Flow rate: 2 mL/min 

Injection size: 20 µL 

System suitability 

Sample: Standard solution 

Suitability requirements 

Retention time: Between 7 and 11 min 

Column eciency: NLT 6000 theoretical plates 

Relative standard deviation: NMT 1.5% 

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of C₁₀H₁₂N₄O₃ in the portion of Oral Solution taken:  

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response of the Sample solution 

r_s = peak response of the Standard solution 

C_s = concentration of USP Didanosine RS in the Standard solution (mg/mL) 

C_u = nominal concentration of didanosine in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0% 

4 PERFORMANCE TESTS 

Deliverable Volume 〈698〉: Meets the requirements 

5 IMPURITIES 

Organic Impurities 

5.1 Procedure 

Solution A, Mobile phase, Sample solution, Chromatographic system, and System suitability: Proceed as directed in the Assay. Standard solution: 5 µg/mL of USP Didanosine Related Compound A RS in water 

[Note—Use this solution within 48 h of preparation.] 

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of didanosine related compound A in the portion of Oral Solution taken: 

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response of didanosine related compound A from the Sample solution 

r_s = peak response of didanosine related compound A from the Standard solution 

C_s = concentration of USP Didanosine Related Compound A RS in the Standard solution (mg/mL) 

C_u = nominal concentration of didanosine in the Sample solution (mg/mL) 

Acceptance criteria: NMT 1% 

6 SPECIFIC TESTS 

Water Determination, Method Ia〈921〉: NMT 3% 

7 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve in tight containers, and store between 15° and 30°. 

Labeling: The label contains directions for constitution of the powder and states the equivalent amount of C₁₀H₁₂N₄O₃ in a given volume of Oral Solution obtained after constitution. 

USP Reference Standards 〈11〉 

USP Didanosine RS 

USP Didanosine Related Compound A RS 

Hypoxanthine