A RAPID AND SENSITIVE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY OF THE NEW ANTIMALARIAL COMPOUND-80 53 IN SERUM WITH A NOVEL SAMPLE CLEANUP METHOD AND ITS PHARMACOKINETICS IN RABBITS/

The compound 80/53 (AM) is a new antimalarial agent synthesized by thi s institute as a safer and less toxic analogue of primaquine. It was f ound to exhibit fluorescence in acetonitrile solution and this finding was exploited to develop a selective and sensitive high performance l iquid chromatographic (HPLC) assay of the AM in rabbit serum. The samp le clean-up was done in a single step by simultaneous protein precipit ation and extraction with acetonitrile in the presence of sodium sulfa te. The lower limit of quantitation of the method was 50 ng ml(-1) usi ng 100 mu l of serum sample. The method was fully validated from 50 to 1600 ng ml(-1) concentration range with a recovery ranging from 70 to 75%. The within- and between-run variability was less than 10% and th e drug in serum was stable over four freeze-thaw cycles and up to 24 h in injection solvent at 4 degrees C. The method was applied to determ ine the pharmacokinetic parameters of AM in 5 rabbits receiving a sing le bolus intravenous and peroral dose in a crossover study. The concen tration-time data after a 5 mg kg(-1) i.v. dose in rabbits was best fi tted to the two compartment body model with first order absorption and elimination rate constants. The terminal half-life and MRT of AM were 95.3 +/- 43.5 and 104 +/- 10.6 min respectively. After administering a single 20 mg kg(-1) oral dose, the serum levels of AM in all the rab bits declined below the quantitation limit by 90 min and it was not po ssible to fit the data by the compartmental approach. The MRT of AM af ter oral dose was 31.1 +/- 8.3 min. Application of the assay has also been extended to analyze the serum samples of rats, monkeys and humans . (C) 1998 Elsevier Science B.V. All rights reserved.