RAPID ANALYSIS OF SOMATOSTATIN IN PHARMACEUTICAL PREPARATIONS BY HPLCWITH A MICROPELLICULAR REVERSED-PHASE COLUMN

A rapid high-performance liquid chromatography method for the analysis of somatostatin in pharmaceutical preparations is described. A commer cially available column packed with 2 mu m spherical non-porous silica -based reversed-phase sorbent is used, along with a mobile phase consi sting of acetonitrile and aqueous phosphoric acid, adjusted to pH 2.8 with sodium hydroxide. The effect of the organic modifier content and column temperature on the retention behaviour of somatostatin is repor ted. The method is found to be highly selective and specific, as indic ated by the baseline separation of a mixture containing somatostatin a nd two analogue peptides, which differ from the analyte for one and tw o amino acids, respectively. Down to 10 ng of somatostatin can be dete cted and the detector response is linear over the concentration range from 4.14 to 20.75 mu g ml(-1). The application of this method to two commercial pharmaceutical formulations of somatostatin is found to giv e a mean percentage recovery from each of the two commercial samples, subjected to multiple injection analysis (n = 5), of 100.9% with a RSD of 0.92%, and 102.6% with a RSD of 1.56%, respectively.