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Within the framework of the Pilot Procurement Project for Quality and Sourcing of HIV Drugs (http:// www.who.int/medicines), the International Pharmacopoeia is collaborating with manufacturers, independent analytical drug quality control laboratories, national and regional pharmacopoeial bodies, research, governments, and regulatory bodies to provide specifications and monographs for the following antiretroviral agents:
abacavir, didanosine, efavirenz, indinavir, lamivudine, nelfinavir, nevirapine, ritonavir, saquinavir, stavudine, zidovudine
Specifications for the respective dosage forms are now being developed and a draft monograph for didanosine is now available for consultation as presented below. This second draft monograph has been developed following comments received on the first draft published in WHO Drug Information, Vol. 17, No. 3 2003. Comments should be sent to: Quality and Safety: Medicines, World Health Organization, 1211 Geneva 27, Switzerland or [email protected].
DIDANOSINUM
Didanosine
Molecular formula: C^sub 10^H^sub 12^N^sub 4^O^sub 3^
Relative Molecular Mass: 236.23
Graphic formula:
Chemical name: 9-[(2R,5S)-5-(hydroxymethyl)tetrahydrofuran-2-yl]-1,9-dihydro-6//purin-6-one; 9(2,3-dideoxy-B-D-glycero-pentofuranosyl)-1,9-dihydro-6//purin-6-one; 2',3'-dideoxyinosine (DDI); CAS Reg. No. 69655-05-6.
Description: A white to almost white powder.
Solubility: Sparingly soluble in water; slightly soluble in methanol R and ethanol (95 per cent) R
Melting point: about 170 °C with decomposition.
Category: Antiretroviral (nucleoside reverse transcriptase inhibitor).
Storage: Didanosine should be kept in a tightly closed container.
REQUIREMENTS
Didanosine contains not less than 98.5% and not more than 101.0% of C^sub 10^H^sub 12^N^sub 4^O^sub 3^calculated with reference to the dried substance.
Identity test
Carry out the examination as described under "Spectrophotometry in the infrared region" (Vol. 1, p. 40*). The infrared absorption spectrum is concordant with the spectrum obtained from didanosine RS or with the reference spectrum of didanosine.
If the spectra are not concordant, use didanosine RS. Dissolve the sample in a small amount of methanol R, evaporate and carry out the IR spectrum as mentioned above. Treat didanosine RS in the same way. The infrared absorpt:on spectrum is concordant with the spectrum obtained from didanosine RS.
Specific Optical Rotation. Use a 10 mg/ml solution...