ABSTRACT
A rapid, reliable and specific reversed-phase high-performance liquid chromatographic procedure is described for the determination of diphenylpyraline hydrochloride at nanogram concentrations in plasma and urine. After extraction of the drug with n-pentane-2-propanol (50:1) from alkalinized samples, the organic extract was evaporated to dryness, reconstituted with methanol and chromatographed using a 5-micron Asahipak ODP-50 C18 column with UV detection at 254 nm. The elution time for diphenylpyraline was 7.9 min. The overall recovery of diphenylpyraline from spiked plasma and urine samples at concentrations ranging from 53 to 740 ng/ml were 94.65% and 92.29%, respectively. Linearity and precision data for plasma and urine standards after extraction were acceptable. The limit of detection was 15 ng/ml for both plasma and urine samples at 0.002 AUFS.
Subject(s)
Chromatography, High Pressure Liquid/methods , Histamine H1 Antagonists/metabolism , Piperidines/metabolism , Histamine H1 Antagonists/blood , Histamine H1 Antagonists/urine , Humans , Piperidines/blood , Piperidines/urine , Sensitivity and Specificity , Spectrophotometry, UltravioletABSTRACT
A simple, sensitive and reliable high-performance liquid chromatographic method for the determination of cyproheptadine in urine by solid-phase extraction (SPE) has been developed. The sample matrix was passed through a pre-conditioned C18 cartridge, washed with methanol-water solution (4:1) and eluted with methanol. The methanolic solution was evaporated to dryness, reconstituted with methanol and chromatographed using a C18 reversed-phase column. The mobile phase consisted of acetate buffer (constant ionic strength of 0.005 I)-methanol (56:44, v/v). Detection was performed at 254 nm with the sensitivity set at 0.002 AUFS. Concentrations as low as 50 ng/ml could be quantitatively determined by an external standard method and the overall recovery was found to be 76.16%, whereas the limit of detection was estimated as 15 ng/ml.