Determination of diphenytriazol (DL111-IT) and its related impurities by RP-HPLC with DAD

An analytical method was developed for determining diphenytriazol and its related impurities in oil injection by using RP-HPLC with DAD and diazepam as internal standard. The C 18 column was used as analytical column. Mobile phase consisted of methanol-potassium dihydrogen phosphate solutions (10 mmol l(-1), pH 7.5) (7:3, v/v). The standard curve was linear in the concentration range from 2 to 100 mug ml(-1) for diphenytriazol. The analytical method afforded average recoveries of 100.3+/-1.9% (n = 9) and the relative standard deviation (RSD) was less than 2% for within-day and between-day precision. The limit of detection and of quantitation for the assay were 15 and 40 ng, respectively. The method was simple, accurate and allowed to be used as analytical method for the routine quality control of diphenytriazol injection. Diphenytriazol injection showed a high stability to the heat (60 degreesC) and the light (4000 lx). (C) 2003 Elsevier Science B.V. All rights reserved.