RESUMO
A simple spectroscopic method was developed for the quantitative determination of the macrolide antibacterials, clarithromycine [Clar] roxithromycin [Rox]. The method is based on the ability of both drugs to form ion associates [ion pair complex] with bromophenol blue which are extractable into dichloromethane. The ion pair complex exhibit maximum absorption at 414 nm with E 1 percent, 1cm of 228 and 234 for Clar and Rox respectively. A linear relationship [r> 0.9994] was established between the absorbance of the extract at 414 nm and the concentration of each drug. The method was linear in the concentration range 10-40 micro g/ml for both drugs. Percentage relative standard deviation of the absorbance values [n=10] at 10 micro g/ml was less than 0.7. The method was used to analyze the antibacterials Clar and Rox in tablets and raw material. Clar was also analyzed in suspension dosage from. Comparison of the method with standard HPLC method has shown that the method is accurate, precise and selective enough for determining the level of the antibacterials in a tablet or suspension preparation