RESUMEN
A tandem-mode high performance liquid chromatography (HPLC) system is described here, which employs reversed phase liquid chromatography (RPLC) followed by strong cation exchange liquid chromatography (SCX), was used to determine the mixture of six ingredients in an ophthalmic solution. As a result of investigations, isocratic HPLC methods that using two columns in tandem-mode; Atlantis dC18 (75 mm x 4.6 mm i.d., 3 microm, ODS) and CAPCELL PAK SCX UG80 (75 mm x 4.6 mm i.d., SCX), which have different separation modes, and control of mixture of methanol/ammonium dihydrogenphosphate buffer as used for the eluent, allowed for six target ingredients to be determined simultaneously. And all ingredients separated perfectly and were determined efficiently and rapidly. Validation of the method was accomplished with respect to linearity (r>0.999), recovery (99.4-100.4%), precision (R.S.D. 0.1-0.9%) and specificity. These results suggest that the fusion of different separation modes can be used for the simultaneous determination of ingredients in ophthalmic solutions, and this can be accomplished rapidly and with high precision.