Hypoxanthine, arabinosides

Uncertain. One suggestion is that the allopurinol causes hypoxanthine arabinoside, the major metabolite of vidarabine, to accumulate by inhibiting xanthine oxidase. A study with rat liver cytosol found that allopurinol greatly increased the half-life of this metabolite. ... 

In an assessment of the vitro susceptibility of HSV to antiviral drugs, utilizing a plaque reduction assaya rabbit kidney cell culture system produced lower MIC s than did a hamster kidney cell system. Of the two types of HSV tested (types I and II, a total of 21 strains), both exhibited an vitro spectrum for susceptibility to IHDR, which may account for some of the differences previously reported. HSV-I was most consistently inhibited by lUDR and Ara-C, while Ara-C was most effective against HSV-II. Adenine arablnoside (Ara-A) and hypoxanthine-arabinoside were less effective against both HSV types. 

In addition to theophylline, purine or pyrimidine derivatives of pharmaceutical interest which have been analyzed include ftorafur, a fluorouracii derivative (429), arabinosides of adenine and hypoxanthine (408), ace-phylline (430), and allopurinol and oxipurinol (431). 

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