The impact of CYP3A5*3 on oral quetiapine: A population pharmacokinetic model in Chinese bipolar disorder patients.

BACKGROUND: There is great interindividual difference in the plasma concentration of quetiapine, and optimizing quetiapine therapy to achieve a balance between efficacy and safety is still a challenge. In our study, a population pharmacokinetic (PPK) model considering genetic information was developed with the expectation of comprehensively explaining this observation in Chinese patients with bipolar disorder. METHODS: Patients who were dispensed quetiapine and underwent the therapeutic drug monitoring (TDM) were included. The genotypes of CYP3A5*3, CYP2D6*10, and ABCB1 C3435T/G2677T were analyzed. Finally, a multivariable linear regression model was applied to describe the PPK of quetiapine considering the covariates weight, height and genotype information. RESULTS: A total of 175 TDM points from 107 patients were adopted for PPK model development. Resultantly, the CL/F of quetiapine in CYP3A5 expressers was 81.1 CL/h, whereas it was 43.6 CL/h in CYP3A5 nonexpressers. The interindividual variability in CL/F was 47.7 %. However, neither the ABCB1 nor CYP2D6 genotype was significantly associated with the predictor of quetiapine clearance in our study. LIMITATIONS: Only trough concentrations were collected, and the span between different points was relatively wide, impeding the application of the typical nonlinear compartment model for PPK analysis. In addition, this was a single-center study which limited the sample of wild-type CYP3A5 carriers. CONCLUSIONS: The currently established PPK model of quetiapine considering the contribution of the CYP3A5 genotype could efficiently predict the population and individual pharmacokinetic parameters of Chinese bipolar disorder patients, which could better guide the personalized therapy with quetiapine, thus to achieve the best clinical response.

Effect of Food on the Pharmacokinetics of Tenofovir Amibufenamide: A Phase I, Randomized, Open-Label, Two-Period Crossover Trial in Healthy Adult Subjects.

Purpose: Tenofovir amibufenamide (TMF) is a novel nucleotide reverse transcriptase inhibitor. The aim of this study was to investigate the effect of food on the single-dose pharmacokinetic properties of TMF. Patients and Methods: In this open-label, randomized, crossover study, after an overnight fast, eligible subjects received a single 25 mg dose of TMF tablet, either under fasted conditions or following consumption of a high-fat, high-calorie meal, followed by a two-week washout period. Blood samples were collected until 144 h after administration. TMF and its metabolite, tenofovir (TFV), were analyzed using validated liquid chromatography-tandem mass spectrometry methods. The geometric mean ratio (GMR) and the corresponding 90% confidence interval (CI) values of AUC0-t, AUC0-∞, and Cmax were acquired for analysis. The absence of an effect of food was indicated if the 90% CI values were within the predefined equivalence limits of 80%-125%. Safety and tolerability were also assessed. Results: For TMF, adjusted GMR (90% CI) values for the fed versus fasted states were 150.28% (125.36%-180.16%), 158.24% (130.42%-192.00%), and 57.65% (45.68%-72.76%) for AUC0-t, AUC0-∞, and Cmax, respectively. For TFV, the GMR (90% CI) of Cmax was 82.00% (74.30%-90.49%) after administration under fed conditions, slightly outside the bioequivalence boundary of 80%-125%, while the corresponding values for AUC0-t and AUC0-∞ were within range. The absorption of TMF was delayed by food, with median Tmax values of 0.33 and 1.00 h in fasted and fed conditions, respectively. The adverse events observed in subjects were all mild. Conclusion: Our results demonstrated that TMF tablets were well-tolerated in healthy volunteers. When TMF tablets were taken with food, Tmax was delayed and exposures of TMF and TFV were higher than under fasted conditions. The modest changes observed are not considered clinically relevant, so TMF can be taken with or without food.

Phase I, Single-Dose Study to Assess the Pharmacokinetics and Safety of Suramin in Healthy Chinese Volunteers.

Purpose: Suramin is a multifunctional molecule with a wide range of potential applications, including parasitic and viral diseases, as well as cancer. Methods: A double-blinded, randomized, placebo-controlled single ascending dose study was conducted to investigate the safety, tolerability, and pharmacokinetics of suramin in healthy Chinese volunteers. A total of 36 healthy subjects were enrolled. All doses of suramin sodium and placebo were administered as a 30-minute infusion. Blood and urine samples were collected at the designated time points for pharmacokinetic analysis. Safety was assessed by clinical examinations and adverse events. Results: After a single dose, suramin maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time zero to the time of the last measurable concentration (AUClast) increased in a dose-proportional manner. The plasma half-life (t1/2) was dose-independent, average 48 days (range 28-105 days). The cumulative percentages of the dose excreted in urine over 7 days were less than 4%. Suramin can be detected in urine samples for longer periods (more than 140 days following infusion). Suramin was generally well tolerated. Treatment-emergent adverse events (TEAEs) were generally mild in severity. Conclusion: The PK and safety profiles of suramin in Chinese subjects indicated that 10 mg/kg or 15 mg/kg could be an appropriate dose in a future multiple-dose study.

Bioequivalence study of domperidone dry suspension in healthy Chinese subjects under fasted and fed conditions: An open-label, randomized, single-dose, crossover trial.

BACKGROUND: Domperidone has long been used as a prokinetic agent in the treatment of epigastric distress symptoms. This study aimed to provide adequate evidence for registration approval of a new generic dry suspension formulation of domperidone by comparing the safety and pharmacokinetic profiles between the test and branded reference formulation in the context of fasted and fed condition. MATERIALS AND METHODS: This was designed as a randomized, open-label, single-dose, two-period, two-treatment crossover study. 32 and 28 eligible healthy subjects were enrolled in the fasted and fed study, respectively. Each subject was randomly assigned to receive either the test or reference formulation in the first period, followed by a 1-week washout period and dosing of the alternate formulation in the second period. A series of blood samples were collected at scheduled timepoints within 48 hours after administration during each treatment period. Plasma concentrations of domperidone were determined by validated HPLC-MS/MS. Pharmacokinetic parameters, including Cmax, tmax, AUC0-t, AUC0-∞, and T1/2, were acquired based on the concentration vs. time profiles by non-compartmental analysis using WinNonlin software. Then the geometric mean ratios (GMR) of Cmax, AUC0-t, and AUC0-∞ between the two formulations and corresponding 90% confidence intervals (CIs) were calculated for bioequivalence determination. Safety was assessed as routine. RESULTS: The two formulations showed similar pharmacokinetic profiles. Under fasted condition, the GMR and corresponding 90% CIs of AUC0-t, AUC0-∞, and Cmax were 101.48% (96.79 - 106.38%), 101.17% (96.66 - 105.90%), and 104.61% (96.73 - 113.14%), respectively. Under fed condition, the GMR and corresponding 90% CIs were 105.46% (99.19 - 112.12%), 104.21% (98.19 - 110.61%), and 112.78% (103.64 - 122.73%), respectively, for AUC0-t, AUC0-∞, and Cmax. All values fell within the accepted bioequivalence range of 80 - 125%. Both the test and the reference products were well tolerated without any serious or unexpected adverse reactions. CONCLUSION: Pharmacokinetic bioequivalence was established between the two dry suspension formulations of domperidone in healthy Chinese subjects. Both products were safe and well tolerated.

The impact of rifampicin on the pharmacokinetics of fuzuloparib in healthy Chinese male volunteers.

AIMS: This clinical study was conducted to evaluate the impact of rifampicin on the pharmacokinetics of fuzuloparib. METHODS: In this single-centre, single-arm, open-label, fixed-sequence study, healthy male subjects took a single 50 mg dose of fuzuloparib on two separate occasions: the first was on Day 1 as monotherapy, and the second was on Day 12 after oral administration of rifampicin 600 mg once daily for 8 days. Series of blood samples were obtained before and after fuzuloparib administration at different time points: pre-dose, and 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 24, 36, 48 and 72 hours post-dose. All samples were examined using liquid chromatography with tandem mass spectrometry. PK parameters were estimated by using a non-compartmental method with Phoenix WinNonlin software. Safety was assessed by monitoring for changes in vital signs and laboratory tests, physical examinations, and incidences of adverse events (AEs). RESULTS: A total of 16 Chinese male subjects were enrolled. Of these, 16 and 15 cases were evaluable for PK analysis following administration with fuzuloparib alone and pretreatment with rifampicin, respectively. Pretreatment with rifampicin resulted in a statistically significant reduction in the systemic exposure to fuzuloparib. The treatment ratio and 90% confidence intervals (CIs) for AUC0-∞ and Cmax were 0.10 (0.095-0.115) and 0.32 (0.281-0.365), respectively. A single administration of fuzuloparib after multiple oral dosing of rifampicin was well-tolerated, without severe AEs. CONCLUSION: The exposure of fuzuloparib was dramatically decreased when pretreated with rifampicin. Strong CYP3A4 inducers should be avoided during fuzuloparib treatment.

Effectiveness of low dose of rapamycin in preventing seizure-induced anxiety-like behaviour, cognitive impairment, and defects in neurogenesis in developing rats.

Aims: Previous studies have demonstrated that rapamycin prevents seizure-induced anxiety-like behaviors. However, rapamycin had been used at a higher dose of 3 mg/kg and resulted in side effects in immature animals. This work was designed to explore whether a lower dose of rapamycin has similar efficacy but has milder side effects.Methods: Acute seizures were induced by injection of pilocarpine at postnatal 10-day Sprague-Dawley rats. Western blot analysis was used to detect changes in mammalian target of rapamycin (mTOR) pathway after seizure. Immunofluorescent intensity of doublecortin (DCX) was conducted to evaluate the development of neurons in hippocampus. Morris water maze and Y-maze test were used to assess cognitive functions and open-field test and elevated plus maze were used to detect anxiety-like behaviors 4 weeks after seizure onset.Results: mTOR pathway was abnormally activated with two peaks after pilocarpine-induced seizures, and no difference of DCX-positive cells and body weight were noticed between control and pilocarpine-induced seizure rats. Pilocarpine-induced seizure in postnatal 10 days rats did not exert impairment on cognitive functions, but resulted in obvious anxiety-like behaviors. Low dose of rapamycin at 0.3 mg/kg significantly reversed seizure-induced increase of p-S6 levels as well as abnormal anxiety-like behaviors. In addition, rapamycin at the dose of 0.3mg/kg did not affect normal development and cognitive functions.Conclusion: lower doses of rapamycin should be used in infants compared with older children or adults.

Rapamycin prevents cerebral stroke by modulating apoptosis and autophagy in penumbra in rats.

Objective: Whether activation or inhibition of the mTOR pathway is beneficial to ischemic injury remains controversial. It may result from the different reaction of ischemic penumbra and core to modulation of mTOR pathway after cerebral ischemia-reperfusion injury in rats. Methods: Longa's middle cerebral artery occlusion (MCAO) method was conducted to induce the focal cerebral ischemia-reperfusion. Western blot analysis was used to examine the protein expression involving mTOR pathway, apoptosis, and autophagy-related proteins. TTC staining and Fluoro-Jade B staining was conducted to detect the infarct volume and cell apoptosis, respectively. Neurological function was measured by modified neurological severity score and left-biased swing. Results: mTOR signaling pathway was activated in ischemic penumbra and decreased in ischemic core after ischemia and ischemia-reperfusion. Ischemia-reperfusion injury induced the increase in cleaved caspase 9 and caspase 3 both in ischemic penumbra and in ischemic core, whereas the expression of phosphorylated ULK1, Beclin 1 and LC3-II was decreased. Rapamycin pre or postadministration inhibited the overactivation of mTOR pathway in ischemic penumbra. Ameliorated neurological function and reduced infarct volume were observed after pre or postrapamycin treatment. Rapamycin markedly decreased the number of FJB-positive cells and the expression of cleaved caspase-3 and cleaved caspase-9 proteins as well as increased the activation of autophagy reflected by ULK1, Beclin-1 and LC3. Interpretation: mTOR signaling pathway was activated in ischemic penumbra after cerebral ischemia-reperfusion injury in rats. mTOR inhibitor rapamycin significantly decreased the mTOR activation and infarct volume and subsequently improved neurological function. These results may relate to inhibition of neuron apoptosis and activation of autophagy.

Akt Inhibitor Perifosine Prevents Epileptogenesis in a Rat Model of Temporal Lobe Epilepsy.

Accumulating data have revealed that abnormal activity of the mTOR (mammalian target of rapamycin) pathway plays an important role in epileptogenesis triggered by various factors. We previously reported that pretreatment with perifosine, an inhibitor of Akt (also called protein kinase B), abolishes the rapamycin-induced paradoxical increase of S6 phosphorylation in a rat model induced by kainic acid (KA). Since Akt is an upstream target in the mTOR signaling pathway, we set out to determine whether perifosine has a preventive effect on epileptogenesis. Here, we explored the effect of perifosine on the model of temporal epilepsy induced by KA in rats and found that pretreatment with perifosine had no effect on the severity or duration of the KA-induced status epilepticus. However, perifosine almost completely inhibited the activation of p-Akt and p-S6 both acutely and chronically following the KA-induced status epilepticus. Perifosine pretreatment suppressed the KA-induced neuronal death and mossy fiber sprouting. The frequency of spontaneous seizures was markedly decreased in rats pretreated with perifosine. Accordingly, rats pretreated with perifosine showed mild impairment in cognitive functions. Collectively, this study provides novel evidence in a KA seizure model that perifosine may be a potential drug for use in anti-epileptogenic therapy.

[Inhibiting mammalian target of rapamycin signaling pathway improves cognitive function in mice with chronic cerebral ischemia].

OBJECTIVE: To investigate the effect of mammalian target of rapamycin(mTOR) inhibitor-rapamycin on cognitive function after chronic cerebral ischemia in mice and its molecular mechanism. METHODS: The chronic cerebral ischemia model was induced by ligation of right common carotid artery (rUCCAO) in 6-week-old ICR mice. The expressions of mTOR, S6K, S6 and corresponding phosphorylated proteins were detected by Western blotting at different time interval (1 h, 3 h, 6 h, 24 h, 3 d, 7 d, 2 w, 4 w, 6 w) after rUCCAO to determine the changes of mTOR signaling pathway. Rapamycin was administrated i.p. at the dose of 3.0 mg/kg 24 h after rUCCAO. Fluoro Jade B staining was used to detect the apoptotic cells. The expressions of Beclin and LC3-Ⅱ were detected by Western blotting to determine the status of autophagy. Morris water maze test and Y maze test were performed to evaluate cognitive functions. RESULTS: The mTOR signaling pathway was abnormally activated from 6 h to 6 w after rUCCAO in mouse cortex. The activation of mTOR signaling pathway induced by rUCCAO was reversed by administration of rapamycin, and the apoptotic cell number was significantly decreased (146.1±16.3 vs 84.5±9.6, P<0.05). Meanwhile, the elevation of Beclin and LC3-Ⅱ protein induced by rUCCAO was reversed by rapamycin administration. Furthermore, compared with vehicle-treated mice, the latent period[(11.1±2.3) s vs (8.1±1.8) s, P<0.05] and swimming distance[(672.8±128.5) cm vs (558.2±124.9) cm, P<0.05] were significantly decreased and the number of crossing the platform quadrant in Morris water maze increased(2.8±0.9 vs 5.2±0.8, P<0.05) in rapamycin-treated mice. Correct response rate in the Y maze was also increased significantly in rapamycin-treated mice[(38.5±9.2)% vs (64.9±7.9)%, P<0.05]. CONCLUSIONS: Inhibiting mTOR pathway by rapamycin reverses the rUCCAO-induced cognitive impairment partly through the suppression of apoptosis and autophagy.

Neural Progenitor Cells Rptor Ablation Impairs Development but Benefits to Seizure-Induced Behavioral Abnormalities.

AIMS: Previous study suggests that mTOR signaling pathway may play an important role in epileptogenesis. The present work was designed to explore the contribution of raptor protein to the development of epilepsy and comorbidities. METHODS: Mice with conditional knockout of raptor protein were generated by cross-bred Rptorflox/flox mice with nestin-CRE mice. The expression of raptor protein was analyzed by Western blotting in brain tissue samples. Neuronal death and mossy fiber sprouting were detected by FJB staining and Timm staining, respectively. Spontaneous seizures were recorded by EEG-video system. Morris water maze, open field test, and excitability test were used to study the behaviors of Rptor CKO mice. RESULTS: As the consequence of deleting Rptor, downstream proteins of raptor in mTORC1 signaling were partly blocked. Rptor CKO mice exhibited decrease in body and brain weight under 7 weeks old and accordingly, cortical layer thickness. After kainic acid (KA)-induced status epilepticus, overactivation of mTORC1 signaling was markedly reversed in Rptor CKO mice. Although low frequency of spontaneous seizure and seldom neuronal cell death were observed in both Rptor CKO and control littermates, KA seizure-induced mossy fiber spouting were attenuated in Rptor CKO mice. Additionally, cognitive-deficit and anxiety-like behavior after KA-induced seizures were partly reversed in Rptor CKO mice. CONCLUSION: Loss of the Rptor gene in mice neural progenitor cells affects normal development in young age and may contribute to alleviate KA seizure-induced behavioral abnormalities, suggesting that raptor protein plays an important role in seizure comorbidities.