ABSTRACT
A rapid, reliable and rugged assay for determining codeine in human plasma using reversed-phase high-performance liquid chromatography with fluorescence detection was developed. This analytical method utilized an ion-exchange/mixed-mode solid-phase extraction procedure. The chromatographic separation was achieved using a 150 x 4.6 mm I.D., 3-microns reversed-phase C8 (deactivated for basic analytes) column at ambient temperature. Fluorescence detection (excitation at 214 nm and emission above 345 nm) for codeine and nalorphine allowed for a detectable limit of 5 ng/ml. The results showed that the method was linear from 10 to 300 ng/ml. The method had good reproducibility, precision, accuracy and recoveries of 91 and 90% for codeine and nalorphine, respectively. This method has been applied to study the pharmacokinetics of codeine in normal human subjects.
Subject(s)
Chromatography, High Pressure Liquid/methods , Codeine/blood , Humans , Nalorphine/blood , Reproducibility of Results , Spectrometry, FluorescenceABSTRACT
A stereospecific HPLC method was developed for the analysis of (-) and (+) pentazocine in human serum. Each enantiomer and the internal standard nalophine were isolated from serum using a liquid-liquid extraction procedure. Recoveries of 99.05 +/- 5.37 and 97.42 +/- 2.78% were obtained for (-) and (+) pentazocine, respectively. Resolution of the enantiomers was obtained by using an ovomucoid chiral stationary phase with a mobile phase of methanol:acetonitrile: 10 mM phosphate buffer, pH 5.8 (20:5.3:74.7 v/v/v). A resolution (Rs) value of 1.80 was obtained for the pentazocine enantiomers. Linear calibration curves were obtained in the 10-100 ng/mL range for each enantiomer in serum. The detection limit based on a signal-to-noise ratio of 3 was 5 ng/mL for each enantiomer in serum using fluorescence detection with excitation at 275 nm and emission set at 335 nm. The lowest quantifiable level was found to be 10 ng for each enantiomer. Precision and accuracy of the method were in the 3.8-4.8% and 1.3-4.2% ranges, respectively.
Subject(s)
Chromatography, High Pressure Liquid/methods , Ovomucin/chemistry , Pentazocine/blood , Chromatography, High Pressure Liquid/instrumentation , Humans , Molecular Structure , Nalorphine/blood , Pentazocine/isolation & purification , Reference Standards , Reproducibility of Results , Spectrometry, Fluorescence , StereoisomerismABSTRACT
A method for the determination of morphine is post-mortem blood by HPLC with electrochemical detection is described. Blood morphine levels in post-mortem cases are reported and the importance of these in causing death is discussed. These post-mortem levels are compared further with morphine levels in the blood of patients receiving morphine as an analgesic.
