Two simple and sensitive spectrophotometric methods (method A and B) were developed for the determination of Famciclovir (FCV) either in raw material or in pharmaceutical formulations. Method A is based on the formation of orange yellow colored chromogen due to the diazotization reaction of FCV with nitrous acid. The orange yellow colored chromogen complex absorbs at λmax 460 nm. Method B is based on reaction of FCV with paradimethylaminocinnamaldehyde (PDAC) resulting in the formation of yellow colored species having absorption maxima at 390 nm. Beer's law is obeyed in the concentration range of 4 – 20 μg/ml for both method A and B. The proposed methods were successfully applied to the assay of FCV in pharmaceutical preparations with recoveries varying from 99.91 to 100.26% (method A) and 99.31 to 100.84% (method B), with relative standard deviation of 1.604% and 0.90% for method A and B respectively. No significant interference was observed from the excipients commonly used as pharmaceutical aids with the assay procedure.
