Abstract
Two sensitive, accurate and precise spectrofluorometric and spectrophotometric methods have been proposed and validated for the determination of the antiviral drug, ribavirin (RBV) in its dosage form and in plasma. Both methods were based on the condensation of RBV with 1,2-naphthoquinone-4-sulfonate (NQS) in an alkaline medium to form an orange-colored product. The spectrofluorometric method involved the reduction of that colored product with calcium hydride (CaH2), and the subsequent measurement of the formed fluorescent product at 406 nm after excitation at 344 nm. The spectrophotometric method involved the measurement of the colored product at 452 nm. The optimum experimental conditions have been studied carefully. Linear relationships with good correlation coefficients (0.9993 and 0.9999) and LOD (0.02 and 1.48 mu g mL(-1)) were obtained in the ranges of 0.05-8.0 and 5.0-65.0 mu g mL(-1) for the spectrofluorometric and spectrophotometric methods, respectively. Both methods were successfully applied to the determination of RBV in capsules. As its higher sensitivity, the spectrofluorometric method was applied to the determination of RBV in plasma. The results obtained by the proposed methods were comparable with those obtained by a reported method.