Quantitation of Cyproheptadine in Plasma and Urine by HPLC

Abstract

A sensitive, reliable and specific high performance liquid chromatographic procedure has been developed for the quantitation of cyproheptadine in plasma or urine. After extraction of the drug with ethyl acetate from alkalinized samples, the organic extract was evaporated to dryness, reconstituted with acetonitrile and chromatographed using a C₈ reversed-phase analytical column with UV detection at 254 nm. The average recoveries of cyproheptadine from spiked plasma and urine samples in the concentrations ranging from 0.2 – 3 mcg/ml were 95.7 and 100.3%, respectively and their respective CV was 4.1 and 3.9%. Regression analyses for the calibration plots for plasma and urine standards obtained on three different days for the drug concentrations between 0.2 – 3 mcg/ml indicated excellent linearity (r > 0.999) and reproducibility (CV < 2.0%, p > 0.01). The limit of sensitivity was 50 ng/ml for both plasma and urine samples. The method was applied to monitor the plasma concentration versus time profile of cyproheptadine following a single bolus IV dose of 1 mg/kg in a dog. Urine samples taken from a human subject for the duration of 24 hours following a single oral dose of 8 mg showed that the cumulative amount excreted in urine as cyproheptadine was approximately 1% of the dose.