High-performance liquid chromatographic assay for thyrotropin releasing hormone and benzyl alcohol in injectable formulation.

A stability-indicating, high-performance liquid chromatographic method is presented for the determination of thyrotropin releasing hormone (TRH) and benzyl alcohol in a multidose injectable formulation. Separation is achieved on a microparticulate octadecylsilica column, with pH 2.2 ion-pair reagent (octanesulfonic acid, sodium salt) solution/methanol/acetonitrile/triethylamine (92:4:4:0.01), at a flow rate of 1.5 ml/min and a detection wavelength of 215 nm. p-Aminobenzoic acid is used as an internal standard. The relative standard deviations of the method are +/- 0.6% for TRH and +/- 0.7% for benzyl alcohol. Recoveries from standard additions to placebos ranged from 99.0 to 101.3 and 99.7 to 101.8% for TRH and benzyl alcohol, respectively.