Didanosine for Oral Solution
» Didanosine for Oral Solution, when reconstituted as directed in the labeling, yields a 10 mg per mL solution that contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of didanosine (C10H12N4O3).
Packaging and storage Preserve in tight containers, and store at a temperature 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.
B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Water, Method Ia 921: not more than 3%.
Deliverable volume 698: meets the requirements.
Mobile phase, Chromatographic system, and Procedure Proceed as directed in the Assay.
Standard solution Dissolve an accurately weighed quantity of USP Didanosine Related Compound A RS in water to obtain a solution containing 5 µg per mL. Make stepwise dilutions if necessary. [noteUse this solution within 48 hours of preparation.]
Test solution Transfer the contents of 1 container of Didanosine for Oral Solution to a suitable volumetric flask, and dissolve in water to obtain a solution having a concentration of approximately 4 mg per mL. [noteUse this solution within 24 hours of preparation.]
Diluted test solution Dilute the Test solution quantitatively, and stepwise if necessary, with water to obtain a solution having a concentration of about 0.1 mg per mL.
Calculate the percentage of didanosine related compound A (hypoxanthine) in the Didanosine for Oral Solution as compared to the didanosine label claim by the formula:
[100(C/1000)(rU / rS)VD]/L
in which 100 is the conversion factor to percent; C is the concentration of didanosine related compound A in the Standard solution, in µg per mL; 1000 is the conversion factor (µg to mg); rU and rS are the peak responses of didanosine related compound A in the Diluted test solution and the Standard solution, respectively; V is the volume, in mL, of Didanosine for Oral Solution used to prepare the Test solution; D is the dilution factor of the Diluted test solution; and L is the didanosine label claim expressed in mg: not more than 1% is found.
0.01 M Ammonium acetate buffer solution Dissolve 1.54 g of ammonium acetate into a 2000-mL volumetric flask, dilute with water to volume, mix, and pass through a 0.45-µm filter.
Mobile phase Prepare a filtered degassed mixture of 0.01 M Ammonium acetate buffer solution and acetonitrile (24:1). Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation Dissolve an accurately weighed quantity of USP Didanosine RS in water to obtain a solution containing 0.1 mg per mL. [noteUse this solution within 24 hours of preparation.]
Assay preparation Transfer the contents of 1 bottle of Didanosine for Oral Solution to a suitable volumetric flask and dilute stepwise, if necessary, to obtain a solution in water of about 0.1 mg per mL. [noteUse this solution within 24 hours of preparation.]
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 254-nm detector, a 4-mm × 25-cm analytical column containing packing L1, and a 4.6- × 20-mm guard column. The flow rate is about 2.0 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the retention time for didanosine is between 7 and 11 minutes; the column efficiency is not less than 6000 theoretical plates; and the relative standard deviation for replicate injections is not more than 1.5%.
Procedure Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of didanosine (C10H12N4O3) in the portion of Didanosine for Oral Solution taken by the formula:
CD(rU / rS)in which C is the concentration, in mg per mL, of USP Didanosine RS in the Standard preparation; D is the volume, in mL, of Didanosine for Oral Solution used to prepare the Assay preparation multiplied by the dilution factor of the Assay preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 2132Pharmacopeial Forum: Volume No. 34(6) Page 1443
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.