DETERMINATION OF 1,3-DI(4-IMIDAZOLINO-2-METHOXYPHENOXY)PROPANE IN RAT, DOG AND HUMAN PLASMA AND URINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION

A sensitive and selective high-performance liquid chromatographic (HPL C) method was developed for the determination of 1,3-di(4-imidazolino- 2-methoxyphenoxy)propane (DMP) in rat, dog and human plasma (50-5000 n g/ml) and urine (0.1-10 mu g/ml). DMP and DMPent (dimethoxyimidizolino pentamidine, the internal standard), are extracted from alkanized plas ma with n-butyl chloride-n-butanol (9:1, v/v). The organic phase is dr ied under nitrogen, reconstituted in mobile phase, and washed with hex ane. Separation is achieved by ion-pair chromatography on a Zorbax Rx C-8 column with fluorescence detection. The analysis of pooled plasma (80, 400, and 4000 ng/ml) and urine controls (0.3, 1.6, and 8 mu g/ml) demonstrated excellent precision and accuracy over a three-day period . The recovery of DMP is >90% from rat, dog, and human plasma and >85% from rat and human urine, and 60-70% from dog urine. The limit of qua ntitation (LOQ) of the assay is 50 ng/ml in rat, dog and human plasma. Using the high-sensitivity assay, the limit of quantitation was decre ased to 5, 2 and 0.6 ng/ml in rat, dog and human plasma, respectively. The LOQ of the assay is 0.1 mu g/ml in rat, dog and human urine. The assay was used to determine plasma and urine concentrations of DMP in pharmacokinetic studies in rat and dog.