• Analytical Science and Technology
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• v.20 no.2
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• pp.138-146
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• 2007

A simple and sensitive method for the determination of paroxetine in canine plasma was developed and validated by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry (LC-/MS/MS). Fluoxetine was used as an internal standard. Paroxetine and internal standard in plasma samples were extracted using TBME (tert-butyl methyl ether). A centrifuged upper layer was then evaporated and reconstituted with mobile phase of 50% acetonitrile adjusted to pH 3 by formic acid. The reconstituted samples were injected into a Capcell Pak UG120 ($2.0{\times}150mm$, $5{\mu}m$) column. Using MS/MS with SRM (selective reaction monitoring) mode, the transitions (precursor to product) monitored were m/z $330{\rightarrow}192$ for paroxetine, and m/z $310{\rightarrow}148$ for internal standard. Linear detection responses were obtained for paroxetine concentration range of 0.02~5 ng/mL. A correlation coefficient of linear regression ($R^2$) was 0.9993. Detection of paroxetine in canine plasma was accurate and precise, with limit of quantification at 0.02 ng/mL. The method has been successfully applied to pharmacokinetic study of paroxetine in healthy beagle dogs.

• Anxiety and mood
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• v.3 no.2
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• pp.110-115
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• 2007

Objective : The authors examined the treatment response and remission rates in patients with panic disorder after short-term pharmacotherapy in an effort to determine the factors that can be used to predict remission in Korean patients with panic disorder. Methods : Sixty-one patients with panic disorder were recruited for participation in this study. The psychological symptoms of the patients were measured using the HAMA, HAMD, STAIS, STAIT, ASI and API at baseline and after 3 months of pharmacotherapy. Results : Patients with panic disorder showed significantly lower scores on all psychological measures after 3 months of pharmacotherapy with paroxetine. The remission rate was 44.3%, and the response rate was 54.1%. The remitters showed significantly lower HAMD, HAMA, STAIS, STAIT, and ASI scores than the non-remitters. Linear regression analysis revealed that the baseline HAMA, HAMD, and ASI scores could be used to predict the remission rate after controlling for age, sex and agoraphobia. Conclusion : Compared with previous reports, our study showed a similar remission rate in Korean patients with panic disorder. Lower baseline levels of anxiety, depression, and anxiety sensitivity were found to be predictors of treatment remission in panic disorder.

• Korean Journal of Biological Psychiatry
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• v.3 no.2
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• pp.251-257
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• 1996

Selective serotonin reuptake inhibitors(SSRIs), as haloperidol, ore metabolized in the cytochrome P450IID6. They can cause inhibition of metabolism of antipsychotics to elevate the serum level of antipsychotics and exacerbate the extrapyramidal symptoms when co-administered with antipsychotics. Among these SSRIs, there ore a few studies about paroxetine compared to fluoxetine or sertraline. In this study, we have intended to know the drug interaction of paroxetine and haloperidol when co-administered two drugs for the chronic schizophrenics by assessing the changes of positive, negative symptoms and extrapyramidal symptoms. for this purpose, we selected 29 subjects, the chronic schizophrenics with no physical problems. They were under maintenance therapy of haloperidol. They ore randomly assigned to placebo group(n=12) and drug group(n=17) by using double blind method. And then, placebo or paroxetine 20mg were administered to the subjects of each groups during 8 week period. We have assessed their psychopathology and extrapyramidal symptoms using Positive and Negative Syndrome Scale(PANSS), Hamilton Rating Scale lor Depression(HRSD), Simpson-Angus Scale at 0, 2, 4, 6, 8 weeks and serum haloperidol, reduced haloperidol levels at 0, 4, 8 weeks during the period. The results ore analysed by using repeated measure MANOVA. 27 subjects have completed the study during 8 weeks. among the subjects, 1) PANSS, HRSD ; no significant difference between groups. 2) Simpson-Angus Scale ; no significant change according to the time and no significant difference between the groups(no group and time effect). 3) Haloperidol and reduced haloperidol level ; no significant change. When co-administered paroxetine and haloperidol, there ore no significant changes of the psychopothology and no significant changes of the extrapyramidal symptoms. In this result, paroxetine seems to be not to affect the metabolism of haloperidol.

• Anxiety and mood
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• v.2 no.2
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• pp.101-107
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• 2006

Object : Since autonomic nerve system dysfunction was known as the mechanism of panic disorder, many researchers used heart rate variability (HRV) as means of measuring autonomic nerve function of patients with panic disorder. We aimed to examine the effect of paroxetine medication for 3 months on symptom improvement and change of heart rate variability of the patients with panic disorder. Methods : The subjects were patients with panic disorder who visited the psychiatric outpatient clinic of Samsung Medical Center in Seoul. We included panic disorder patients who were aged from 20 to 50 and in normal BMI range (from 18 to 30) to minimize the effect of age and weight on HRV data. We excluded the patients with EKG abnormalities, hypertension or other major psychiatric disorders. They took 20-40 mg paroxetine medication a day for 3 months. Alprazolam was used only during the first month to control the acute panic symptoms and was tapered off after that. We measured the acute panic inventory (API), Hamilton rating scale for anxiety and depression (HAM-A & HAM-D), Spielberger state-trait anxiety inventory (STAIS, STAIT), and Beck depression inventory (BDI) in order to assess clinical improvement of the patients. And we measured time and frequency domain HRV in the resting, standing and cognitive stress states to assess the change of HRV. All measurements were done before and after paroxetine treatment. Result : After paroxetine medication, patients showed significant improvement in all psychiatric scales. In time domain of HRV, standard deviations of all R-R intervals (SDNN) were significantly increased in all states. In frequency domain of HRV, the ratio of high frequency to total power (HF/TP) in the standing state was significantly increased. Conclusion : After 3 months paroxetine medication, panic disorder patients showed significant clinical improvement and change in HRV data such as SDNN in all states and HF/TP ratio in the standing state. This result suggests that paroxetine medication is effective for the improvement of autonomic nerve system dysfunction in panic disorder patients.

• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.499-504
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• 2004

Paroxetine, a potent and selective serotonine reuptake inhibitor, has been used for the treatment of depression, obsessive-compulsive disorder, panic disorder and social phobia. The bioequivalence of two paroxetine preparations was evaluated according to the guidelines of Korea Food & Drug Administration (KFDA). The test product was Samchully Paroxetine $tablet^{\circledR}$ made by Samchully Pharm. Co. and the reference product was Seroxat $tablet^{\circledR}$ made by GlaxoSmithKline. Twenty healthy male subjects, $22.4{\pm}2.6$ years old and $63.8{\pm}4.2\;kg$, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After one tablet containing 20 mg paroxetine was orally administered, blood was taken at predetermined time intervals and the concentration of paroxetine in plasma was determined using a validated HPLC method with fluorescence detector. Two pharmacokinetic parameters, $AUC_t$ and $C_{max}$, were calculated and analyzed statistically for the evaluation of bioequivalence of two products. Analysis of variance was carried out using logarithmically transformed parameter values. The 90% confidence intervals of $AUC_t$ and $C_{max}$ were log 0.84-log 1.16 and log 0.85-log 1.14, respectively. These values were within the acceptable bioequivalence intervals of log 0.8 to log 1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating that Samchully Paroxetine tablet is bioequivalent to Seroxat tablet.