Agents acting on the central nervous system. 14. 1-(p-Alkanoylphenoxy)-3-(N 4 -arylpiperazinyl)propan-2-ols. A new class of antidepressants

1- and 2-substituted naphthalenes: a new class of potential hypotensive agents

A series of 2-substituted aminomethyloxy naphthalenes 1 and 4-(1-naphthoxy-2-substituted aminomethyl)-butanoic acids 2 were synthesized by Mannich reaction of 4-(2-naphthoxy)-butanoic acid 3 and 4-(1-naphthoxy)-butanoic acid 4 with appropriate secondary amines and para-formaldehyde. The newly synthesized compounds were tested for their hypotensive activity at 5 mg/kg i.v. dose in cats. The results indicated that the analogue 2-(N4-phenyl-N1-piperazino)-methyloxy naphthalene 1d (> N = N4-phenyl-N1-piperazino) was the most active analogue when its hypotensive activity was compared to the reference compound propranolol.

Isolation and characterization of metabolites of centpropazine in rat liver, intestine, and red blood cell homogenates

The potential sites for metabolism of centpropazine (CPZ) (an antidepressant) were evaluated in male Sprague-Dawley rats. The isolation and identification of the major metabolites formed in the presence of rat liver S9 fraction, intestine, and red blood cells under aerobic conditions were performed using high-performance liquid chromatography and electrospray ionization mass spectrometry. CPZ was found to be extensively metabolized to seven possible metabolites by liver S9 fraction in the presence of a nicotinamide adenine dinucleotide phosphate generating system at 37 degrees C. Both intestinal wall and red blood cells were also found to metabolize the compound. This metabolite structure was confirmed by comparison with that of its synthetic standard. The drug was stable in intestinal contents. On the basis of our finding, we propose the in vitro metabolic pathways for CPZ.

Determination of centpropazine and its metabolite in rat serum by high-performance liquid chromatography and fluorescence detection

A new HPLC assay method was developed for the simultaneous assay for centpropazine (antidepressant) and its hydroxylated metabolite (II) to assess their pharmacokinetics and metabolism characteristics. Rat serum samples were extracted with ether, backwashed with n-hexane and injected onto the HPLC system, which used a C18 column, gradient elution and fluorescence detection at 250 Ex/350 nm Em. Variations in intra- and inter-batch accuracy and precision were within acceptable limits of < +/- 20% at low and < +/- 15% at higher concentrations. Samples were stable in autosampler prior to injection and after multiple freeze-thaw cycles. Linearity was observed between 0.625 and 20 ng/ml for both I and II in serum. Overall the method developed was highly sensitive and could be employed for a wide range of studies.

Development and validation of a new high-performance liquid chromatographic assay of centpropazine, a new antidepressant compound, in serum

Centpropazine is a new anti-depressant compound developed by Central Drug Research Institute, Lucknow (India). We report here the development and validation of a new HPLC assay of a parent drug in the serum of humans, monkeys and rats for pharmacokinetic studies. Centpropazine was eluted on a C18 column with a mobile phase consisting acetonitrile phosphate buffer (60:40) pumped at 1.5 ml min(-1) flow rate and quantitated by UV detector at 270 nm. Considering the sample volume available from different species and to enhance the sensitivity of assay, three sample clean up methods requiring 0.05, 0.5 and 4 ml serum for a linear quantitation range of 312.5 ng ml(-1)-5 microg ml(-1), 0.04-2.5 microg ml(-1) and 2.5-80 ng ml(-1) respectively were developed. The lowest limit of quantitation of the method was 2.5 ng ml(-1) requiring 4 ml serum, 40 ng ml(-1) requiring 0.5 ml serum and 312 ng ml(-1) requiring 50 microl serum sample. All these methods were fully validated in human serum and extended to monkey and rat serum. The recovery of centpropazine at 5, 80, 625, 1280 and 2500 ng ml(-1) ranged between 92 and 105%. The within and between run variability in precision and accuracy were less than 10% and the drug in serum was stable up to three freeze-thaw cycles. Overall the method is simple, quick and robust for biopharmaceutical applications. The method was applied to analyse concentrations of centpropazine in rat serum after administering single 20 mg kg(-1) peroral and 5 mg kg(-1) i.v. dose. The chromatograms of treated rat serum exhibited three well resolved peaks of metabolites and one of them was identified as hydroxy-metabolite of centpropazine.