HPLC assay and bioequivalence evaluation of biphenyl dimethyl dicarboxylate (DDB) products

A high-performance liquid chromatographic (HPLC) method was developed for biphenyl dimethyl dicarboxylate (DDB) detection in human serum and bioequivalence (BE) of two commercial DDB tablets was evaluated in 14 normal male subjects. The most suitable extracting solvent for DDB in serum was evaluated among dichloromethane, ether, ethylacetate, hexane, and pentane. Pentane:ether (9:1) mixture showed good extraction recovery of DDB from serum and also excluded serum components, which interfere the peak of DDB when assayed. HPLC conditions were as follows: UV absorbance detector, 280 nn; column, mu-Bondapak C-18; mobile phase, 10 mM phosphate buffer (pH 6.0), 33% acetonitrile, and 17% methanol; sensitivity, 0.005 aufs. BE was evaluated by 2x2 Latin square crossover method. DDB tablets (200 mg as DDB) were given orally and the serum concentration was detected by HPLC. The pharmacokinetic parameters, AUC(t), C-max, and t(max) obtained after dosing were statistically analyzed by ANOVA for crossover design, The results for all parameters were within 20% difference of mean value between reference and test drug. The results of ANOVA showed no significant differences for between group or subject and period. From the results, it is concluded that the bioavailability of test drug is not significantly different from reference drug and the two drugs are bioequivalent.