Anodic polarographic determination of josamycin in formulations and spiked human urine

The anodic polarographic behaviour of josamycin (a macrolide antibiotic) has been studied using direct current (DC(t)) polarography and differential pulse polarography (DPP). In Britton-Robinson buffers (BRb) josamycin exhibited well-defined anodic polarographic waves in the pH range 2-8. In BRb of pH 6, the diffusion-current constant was 1.62 microA mmol(-1) (n = 6). The current-concentration plots are rectilinear over the range 10-50 and 5-40 microg/ml using the DC(t) and DPP modes, respectively, with a detection limit of 4.83 x 10(-6) M adopting the DPP mode. The method was applied to commercial tablets adopting both DC(t) and DPP modes, the recoveries % were 99.13 +/- 2.22 (n = 10) and 99.82 +/- 1.82 (n = 7), respectively. The method was further extended to the in vitro determination of josamycin in human urine, the recovery % (n = 6) was 100.06 +/- 2.84. The number of electrons involved in the electrode process could be accomplished and a proposal of electrode reaction was presented.