High-performance liquid chromatographic analysis of pentazocine in blood and plasma

An efficient method for simultaneous detection of Pheniramine, Pentazocine and cotinine in urine by Gas Chromatography in De-addiction program

Background

Nonmedical use of prescription drugs for recreational purposes is a major health problem that raises high concerns for public health. Recently, several laboratory studies have reported the misuse of pentazocine, an agonist-antagonist opioid in combination with antihistamines in opioid addicts. Illicit self-administration of prescription drugs has been increasingly reported in India. Urinalysis as an adjunct to self-report plays a key role in providing additional information in the treatment of drug users. This paper aims to discuss a simple, convenient, and rapid capillary column gas-liquid chromatography method for simultaneous detection of pentazocine, pheniramine, and cotinine in urine.

Methods

The sample was extracted with chloroform and isopropanol (3:1,v/v) and evaporated to dryness. After reconstitution with methanol, it was directly subjected to gas chromatography analysis. Method performance was evaluated and validated in terms of sensitivity, precision, the limit of detection (LOD), and the limit of quantification (LOQ).

Findings

The linearity obtained was in the range of 50-1000 ng/ml with a correlation coefficient (r) above 0.999 for each drug. Good LOQ (50ng/ml) was obtained with each drug. Also, the developed method was effective in analyzing samples from patients with suspected abuse of these drugs.

Conclusion

The technique was found to be simple, robust, sensitive, and precise in the simultaneous analysis of drugs (pentazocine, pheniramine, and cotinine). This method was proved to be useful and cost-effective in treating and monitoring patients seeking help for addiction in clinical settings.

Sensitive determination of pentazocine in human tissues by high-performance liquid chromatography

The authors developed a simple, reliable and sensitive method for the determination of pentazocine in human solid tissues using high-performance liquid chromatography, combined with a three-step liquid-liquid extraction procedure. Levallorphan tartrate served as the internal standard. The extract was evaporated to dryness and dissolved in the mobile phase of acetonitrile/10 mM phosphate buffer (pH 4.0). The eluent was pumped at a flow rate of 0.4 ml/min through a Spherisorb Ph (2.1 mm I.D. x 150 mm) column. A fluorescence detector with excitation at 247 nm and emission at 320 nm was used. The lower limit of detection was about 0.5 ng/g. The calibration curve was linear over the concentration ranges from 1 to 500 ng/g in each tissue examined and could be determined up to at least 10.0 microg/g by means of reduction of injected volumes. Using this method, the concentrations of pentazocine could be determined in the tissues of an autopsied individual for toxicological evaluation.

Liquid chromatography-fast atom bombardment mass spectrometry for detection and determination of pentazocine in human tissues

A reliable and sensitive method was developed for the detection and determination of pentazocine in human solid tissues using liquid chromatography-dynamic fast atom bombardment (FAB) mass spectrometry, combined with a three-step liquid-liquid extraction procedure. Levallorphan tartrate served as an internal standard. The extract was evaporated to dryness and dissolved in the mobile phase, acetonitrile-10 mM ammonium acetate solution (20:80, pH 4.0) containing 0.5% glycerol as FAB matrix. The eluent was pumped at a flow rate of 25 microl/min and split before introduction to FAB mass spectrometer. Quantitative analysis was carried out by means of monitoring quasi-molecular ions with m/z 286 for pentazocine and m/z 284 for levallorphan. The lower limit of detection of pentazocine in each tissue tested was 1 ng/g with scan mode and 0.1 ng/g with SIM mode. Using this method, the concentrations of pentazocine were determined in the tissues of an autopsied individual to perform toxicological evaluation.

HPLC separation of pentazocine enantiomers in serum using an ovomucoid chiral stationary phase

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.