Dissolution testing of marketed rifampicin containing fixed dose combination formulations using a new discriminative media : a post marketing retrospective study

Currently recommended compendial dissolution methods for quality control of orally administered solid dosage forms of rifampicin containing formulations are not found to be able to forecast the in vivo performance. A recently proposed dissolution method of 0.01 N HCI at 50 rpm using paddle apparatus for screening was found to be more appropriate and able to predict the in vivo performance of those formulations. The objective of this investigation was to validate the new method of dissolution testing for solid dosage forms of rifampicin containing formulations using a basket apparatus and to compare it with the frequently recommended pharmacopeial method. In the present study the newly proposed dissolution condition (0.01 N HCI) was validated using six formulations of two, three and four drug combinations from two different manufacturers by basket method and compared with the widely recommended compendial medium. In this investigation, the appropriateness of the proposed methodology was confirmed by the dissolution results of the two FDC formulations (a two-drug and a four-drug combinations) that had previously passed the bioequivalence tests. It was found that the recommended dissolution medium of 0.01 N HCI can be used for screening of rifampicin containing formulations using both paddle and basket dissolution apparatus at 50 rpm and 100 rpm, respectively.