An Alternative Approach to Isoganciclovir: A Prominent Impurity in the Antiviral Drug Ganciclovir.

A simple and efficient process for the preparation of (±)-9-[(2,3-dihydroxypropoxy)methyl]guanine (isoganciclovir) is described. The synthesis features the preparation of a kinetically and thermodynamically controlled acyclic side chain using masked glycerol and methoxymethyl acetate. The unwanted regioisomers were separated through selective crystallization, which upon deprotection yielded isoganciclovir in good yield.

Identification, Isolation, and Characterization of a New Degradation Impurity in Nafcillin Sodium.

A new degradant of Nafcillin Sodium was found at a level of 1.8% w/w during the gradient reversed-phase HPLC analysis in stability storage samples. This impurity was identified by LC-MS and was characterized by (1)H-NMR, (13)C-NMR, LC/MS/MS, elemental analysis, and IR techniques.

Gradient RP-HPLC method for the determination of potential impurities in atazanavir sulfate.

This paper proposes a simple and selective RP-HPLC method for the determination of process impurities and degradation products (degradants) of atazanavir sulfate (ATV) drug substance. Chromatographic separation was achieved on Ascentis(®) Express C8, (150mm×4.6mm, 2.