Abstract

Due to their anti-inflammatory and antioxidant properties, pentoxifylline and melatonin have been considered by many authors as potential adjuvants in coronavirus disease infection. The present study describes the development of a high performance liquid chromatography method with ultraviolet detection for the simultaneous determination of pentoxifylline and melatonin in spiked plasma samples. The chromatographic separation was performed isocratically at a temperature of 25°, using a LiChrosorb® reverse phase-18 (125×4.0 mm, 5 μm) as stationary phase. The mobile phase consists of water and acetonitrile in a ratio of 80:20 v/v. Under optimal chromatographic conditions, for both pentoxifylline and melatonin, the number of theoretical plates was >2000, peak asymmetry was <1.3 and resolution factors were >2. The relative standard deviations for pentoxifylline and melatonin for both intra-day and interday not exceeded 4 % and recoveries were in the ranges 99.46 %-102.51 % for pentoxifylline and 96.02 %-102.85 % for melatonin.