Determination of fluoxetine ，norfluoxetine and sertraline concentration in human placental perfusate and their placental permeability by UFLC-MS/MS / 中国药房

OBJECTIVE To establish t he method for determining the concentrations of fluoxetine ，norfluoxetine and sertraline in human placental perfusate method and their placental permeability. METHODS Using glyburide as internal standard ，the samples were pretreated by protein precipitation method and detected by ultra-fast liquid chromatograph-mass spectrometer/mass spectrometer （UFLC-MS/MS）. The determination was performed on Synergi TM Hydro-RP 80A LC column with mobile phase consisted of water （containing 0.1％ formic acid ）-acetonitrile（containing 0.1％ formic acid ）at the flow rate of 0.70 mL/min，with a gradient elution. The column temperature was set at 40 ℃，and sample size was 5 μL. Detection was performed with electrospray ionization source in multipl e reaction monitoring mode . The ion pairs for quantitative analysis we re m/z 309.9→148.1（fluoxetine），m/z 296.0→134.4 （-167）， （norfluoxetine），m/z 306.1→159.0 （sertraline），m/z 493.9→ No.2018FE001（-207），（internal standard ）. The perfusion model of singal placenta under bidrectional cardiopulmonary bypass was established. Fluoxetine （160 ng/mL），norfluoxetine（160 ng/mL）， sertraline（100 ng/mL）and antipyrine （positive control ，ng/mL）were added into the maternal perfusate. The concen- 65324888 trations of fluoxe tine， norfluoxetine and sertrali ne were measured by above UFLC-MS/MS at 0，10，20，30，45，60，90，120，150 and 180 min of circulation ，and the placental permeability was calculated. RESULTS The linear range of fluoxetine ，norfluoxetine and sertraline were 5.00-500 ng/mL（all r＞ 0.990），and the lower limits of quantification were all 5.00 ng/mL. The RSDs of intra-day and inter-day were all less than 14.0％， and relative error ranged －9.6％ to 14.7％. The relative error of stability test was －4.0％ to 11.0％；the residual effect ，extraction method and matrix effect did not affect the quantitative analysis of the substance to be tested. Totally 31 perfusion model of human placenta under cardiopulmonary bypass were successfully established ，including 15 fluoxetine and norfluoxetine perfusion ，10 sertraline perfusion and 6 antipyrine perfusion. After 3 hours of perfusion ，the average placental permeability of fluoxetine ， norfluoxetine and sertraline were （8.74 ± 1.67）％ ，（10.70 ± 4.81）％ ，（5.90 ± 1.25）％ ，respectively. CONCLUSIONS The established UPLC-MS/MS is simple ，sensitive and accurate. It can be used for determination of fluoxetine ，norfluoxetine and sertraline in human placental perfusate. Fluoxetine ，norfluoxetine and sertraline can pass through the placenta ，but sertraline has a lower placental permeability.

Analysis of Adherence to Fluoxetine Treatment through its Plasma Concentration

Abstract Depression plays an important role in non-adherence to medical recommendations. Fluoxetine is a first line of depression treatment. This study aimed to evaluate adherence to drug therapy in fluoxetine users by different methods. A cross-section study was conducted with 53 depressed patients on fluoxetine for at least six months. Drug therapy adherence was assessed by validated questionnaires [Brief Medication Questionnaire (BMQ) and Morisky-Green test (MG)] and by the blood concentration of fluoxetine and its active metabolite norfluoxetine. Blood samples were taken before the daily first dose of fluoxetine. The plasmatic concentration of fluoxetine and norfluoxetine indicated that 58.5% volunteers were within the recommended therapeutic range and thus considered adherent to drug therapy. However, questionnaires indicated a non-adherent majority: 41.5% patients had a high degree of adherence in MG and only 13.2% were adherent to pharmacological treatment in BMQ. Most fluoxetine users showed a plasma concentration of fluoxetine and norfluoxetine within the therapeutic range, despite the low adherence to the drug therapy evaluated by the questionnaires. Thus, we suggest that plasma levels of fluoxetine and norfluoxetine could be used as the main method to check adherence to treatment.

Inhibition by Norfluoxetine, the Major Metabolite of Fluoxetine, of Voltage-Gated K+ Channels in Primary Cultured Rat Hippocampal Neurons / 대한마취과학회지

BACKGROUND: Fluoxetine (Prozac), a selective serotonin reuptake inhibitor, has been shown to be effective in the treatment of depression. We investigated the effects of norfluoxetine, the major active metabolite of fluoxetine, on voltage-gated K+ currents in primary cultured hippocampal neurons, and determined the potency and modes of actions of norfluoxetine. METHODS: Voltage-gated K+ currents were studied in primary cultured rat hippocampal neurons using the whole-cell configuration of the patch-clamp technique. Electrophysiological recordings were done in hippocampal neurons between 5-10 days in culture. Transient A-type K+ currents (KA) and delayed-rectifier K+ (KDR) currents were isolated from whole-cell K+ currents using a pulse protocol. RESULTS: Norfluoxetine accelerated the decay rate of whole-cell K+ currents, and thus decreased the current amplitude at the end of a pulse in a concentration-dependent manner. Norfluoxetine inhibited KA and KDR currents in a concentration-dependent manner with IC50's of 0.93 and 0.70micro M, respectively. Norfluoxetine also reduced the areas of KA currents and the steady-state KDR current over the range of test potentials, and the reduction was voltage-dependent (greater increase at more positive potentials). From the onset of the fractional block of KA currents by norfluoxetine during the initial 40 ms of a clamp step, we calculated k1 = 53.26/micro M.s for the association rate constant, and k2 = 70.24/s for the dissociation rate constant. The resulting apparent KD was 1.32micro M, which is similar to the IC50 value obtained from the concentration-response curve. CONCLUSIONS: Our results indicate that norfluoxetine, the major metabolite of fluoxetine, at therapeutic levels, produces a concentration- and voltage-dependent inhibition of KA and KDR currents in primary cultured hippocampal neurons. These effects could perturb the neuronal excitability in the hippocampus, and may contribute to the therapeutic antidepressant action of fluoxetine.

Pharmacokinetics of fluoxetine and its effects on cytochrome P450 isoenzymes / 中国药理学通报

Fluoxetine is a relatively novel class of selective serotonin reuptake inhibitors (SSRIs) with antidepressant properties. It seems to facilitate serotonergic transmission via down regulation of presynaptic inhibitory autoreceptors, with no effect on muscarinic receptors and doubtful effects on ? adrenergic receptors. Fluoxetine is mainly metabolized by cytochrome P450 (CYP) isoenzymes. It has been shown that CYP2C9、CYPD6, and CYP2C19 are major CYP isoforms responsible for the N demethylation of fluoxetine. Since both fluoxetine and its main metabolite norfluoxetine are the inhibitors of CYP2D6, CYP3A4, CYP2C9, and CYP2C19, there are some drug drug interactions of fluoxetine with other drugs for metabolism by those CYP isoenzymes, which results in interindividual differences in the pharmacokinetics and efficacy.