Assay of citrate in pharmaceutical matrices by indirect photometric liquid chromatography.

The development of a simple HPLC procedure is described for the analysis of citrate in pharmaceutical formulations using the technique of indirect photometric chromatography. A novel mobile phase, using dual eluent species, was developed for rapid elution of citrate. The developed method was found to be linear over the range studied (1-12 micrograms of citrate injected), showed good per cent recoveries (+/- RSD) of 97.5 +/- 3.05% from a generalized matrix solution, and includes very simple sample preparation steps for analysis of commercial products. This method is quite specific for tricarboxylic acids as most other ions are not retained by the column using the developed mobile phase. The resolution of the method is also good as indicated by a baseline resolution (Rs = 1.5) obtained for citrate and tricarballylate, two structurally similar tricarboxylic acids. It is proposed that the developed method be evaluated as an alternative to the tedious procedures employed by the USP for assay of total citrate in some of its monographs.