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The pharmacokinetic variability of lamotrigine (LTG) plays a significant role in its dosing requirements. Our goal here was to use noninvasive clinical parameters to predict the dose-adjusted concentrations (C/D ratio) of LTG based on machine learning (ML) algorithms. A total of 1141 therapeutic drug-monitoring measurements were used, 80% of which were randomly selected as the "derivation cohort" to develop the prediction algorithm, and the remaining 20% constituted the "validation cohort" to test the finally selected model. Fifteen ML models were optimized and evaluated by tenfold cross-validation on the "derivation cohort,” and were filtered by the mean absolute error (MAE). On the whole, the nonlinear models outperformed the linear models. The extra-trees’ regression algorithm delivered good performance, and was chosen to establish the predictive model. The important features were then analyzed and parameters of the model adjusted to develop the best prediction model, which accurately described the C/D ratio of LTG, especially in the intermediate-to-high range (≥ 22.1 μg mL−1 g−1 day), as illustrated by a minimal bias (mean relative error (%) = + 3%), good precision (MAE = 8.7 μg mL−1 g−1 day), and a high percentage of predictions within ± 20% of the empirical values (60.47%). This is the first study, to the best of our knowledge, to use ML algorithms to predict the C/D ratio of LTG. The results here can help clinicians adjust doses of LTG administered to patients to minimize adverse reactions.

BACKGROUND The objective of this study was to investigate the serum concentrations of olanzapine in relation to age, sex, and other factors in Chinese patients aged between 10 and 90 years. METHODS Data for 884 olanzapine patients, deposited between 2016 and 2017, were retrieved from the therapeutic drug monitoring database of the Affiliated Brain Hospital of Guangzhou Medical University. The effects of covariates on serum olanzapine concentration, dose-normalized concentration (C/D ratio), and normalized concentration (C/D/weight) were investigated. RESULTS Generally, male patients had lower olanzapine concentration, C/D ratio, and C/D/weight than female patients (P < 0.001). Smoking and drinking reduced olanzapine concentration, C/D ratio, and C/D/weight (P < 0.001). Coadministration with valproate decreased olanzapine concentration, C/D ratio, and C/D/weight by about 16%, 30%, and 40%, respectively (P < 0.001). Patients younger than 60 years had higher olanzapine concentrations (P < 0.05) but lower C/D ratios and C/D/weight (P < 0.001) than patients older than 60 years. Age was correlated with olanzapine concentration (r = -0.082, P < 0.05), C/D ratio (r = 0.196, P < 0.001), and C/D/weight (r = 0.169, P < 0.001). Sample timing after dose and diagnostic factors also contributed to the olanzapine concentrations. Multiple linear regression analysis revealed significant influences of dosage, age, sex, valproate comedication, smoking, postdose interval, and schizophrenia (vs bipolar affective disorders) on serum olanzapine concentrations. CONCLUSIONS The metabolism of olanzapine may be altered by several factors. Patients characterized with a combination of factors may benefit from therapeutic drug monitoring for the adjustment of olanzapine dose to minimize adverse reactions.

Purpose This study aimed to investigate the influence of diagnosis, body weight, sex, age, smoking, formulations, and concomitant drugs on steady-state dose-corrected serum concentrations (C/D) of venlafaxine (VEN) and O-desmethylvenlafaxine (ODV). Methods A retrospective analysis of therapeutic drug monitoring (TDM) was carried out. Patients' demographic data, therapeutic regimens, and concentrations were collected. Results We included 91 verified samples from 80 patients. Females had by average 13% smaller body weight, 50% higher C/D of VEN, and VEN + ODV and 25% smaller ODV/VEN than males. Patients >60 years had by average 33-59% higher C/D levels of ODV and VEN + ODV than younger patients. The concomitant use of valproic acid caused an average 51% higher C/D of ODV and a 2.2-fold larger ODV/VEN, while clozapine was related with 40% smaller ratio of ODV/VEN and 38% lower C/D levels of ODV. Positive correlations were detected between valproic acid concentrations and the C/D of VEN and VEN + ODV. In a multiple linear regression analysis, variance in the C/D of VEN + ODV was partly attributed to the daily dose of VEN, sex, age and valproic acid concentration. Conclusion Our results suggested daily dose of VEN, sex, age, and valproic acid as indicators for the C/D of VEN + ODV in Chinese patients. TDM as a valuable tool was suggested in elderly female patients and patients receiving polypharmacy.

The objective of this study was to evaluate the prevalence and relative risk of off-label prescription of antidepressants in Chinese pediatric outpatients according to China Food and Drug Administration (C-FDA) and USFDA regulations. Medical records of 18 459 pediatric outpatients were identified between 2013 and 2015. Patient characteristics, prevalence of off-label antidepressant prescriptions, and relative risk factors associated with off-label prescribing were analyzed. The results indicate that patients aged from 12 to 17 years account for 88.1% of antidepressant prescriptions, with the most commonly prescribed being sertraline (41.4%). In total, 90.0 and 84.1% of antidepressant prescriptions were off-labeled according to C-FDA and USFDA, respectively, and off-label indications was the most frequent type in this study. Depression was the most common indication for antidepressant treatment, followed by bipolar disorder and schizophrenia. Patients aged 12-17 years diagnosed with bipolar affective disorder have a high risk of off-label antidepressant prescription according to C-FDA regulations. Patients diagnosed with obsessive-compulsive disorder have a low risk of off-label antidepressant prescription according to both regulations. Therefore, future studies are recommended to collect evidence to safeguard appropriate prescribing of off-label antidepressants among pediatric patients.

PURPOSE/BACKGROUND Blonanserin is a novel antipsychotic drug approved for the treatment of schizophrenia in East Asia. The main objective of the present study was to investigate the effect of alcohol on the pharmacokinetic properties of blonanserin and its metabolite N-deethyl blonanserin in healthy Chinese male subjects under fasting conditions. METHODS/PROCEDURES The study was designed as a randomized, open-label, crossover clinical investigation in 10 male volunteers, each of whom received 2 treatments under fasted conditions: treatment A, blonanserin (8 mg) with water, and treatment B, blonanserin (8 mg) with alcohol (1 mL/kg). FINDINGS/RESULTS The average values of areas under the curve (AUCs) and mean peak plasma concentrations (Cmax) were noticeably increased by alcohol consumption. In treatment A, average values of AUC0-24h, AUC0-∞, and Cmax were 3178 ng/h/L, 3879 ng/h/L, and 492 ng/L for blonanserin, and 1932 ng/h/L, 4208 ng/h/L, and 137 ng/L for N-deethylated blonanserin, respectively. In treatment B, AUC0-∞ and Cmax were both increased 2.4-fold for blonanserin and 1.4-fold and 1.7-fold, respectively, for N-deethylated blonanserin (P < 0.05). Compared with treatment A, clearance (Clz/F) of blonanserin and N-deethylated blonanserin decreased significantly (2.4-fold and 1.7-fold, respectively) in treatment B (P < 0.05). Alcohol delayed the absorption and reduced the clearance of blonanserin, leading to a 1.8-fold increase in the time to reach Cmax (Tmax) and half life time (t1/2) (P < 0.05). IMPLICATIONS/CONCLUSIONS Alcohol increased the bioavailability of blonanserin and N-deethyl blonanserin in healthy subjects and the marked effect of alcohol on blonanserin bioavailability should be taken into consideration in deciding dosing schedules in clinical therapy.

It is of great significance in the resource utilization to make full use of the magnesium in the low-grade mineral to prepare new adsorption materials. In this paper, a Mg(OH)2/talc nanocomposite was prepared by migrating part of Mg2+ from the talc internal structure to the outer surface through a facile acid leaching, coprecipitation and hydrothermal method. The maximum adsorption capacity of Mg(OH)2/talc was 483.33 mg/g, which was significantly improved compared with that of Acid-activated Talc (4.79 mg/g) and pristine talc (259.17 mg/g). The main adsorption mechanism of Mg(OH)2/talc for Pb(II) ions involved electrostatic attraction and ion exchange. Adsorption and desorption cycle experiment showed that, although Mg(OH)2/talc provides a large adsorption capacity for the first time, but the second adsorption capacity decreased by 42%, the third to the fifth kept stable adsorption capacity. This results indicated that the surface of magnesium hydroxide was not stable, only used it once. While magnesium hydroxyl in talc was stable, it could provide stable cycle performance. This work can provide reference for efficient utilization of clay minerals and design novel cost-efficient adsorbents.

Objective To evaluate the effects of treatment with risperidone and aripiprazole on serum prolactin, testosterone and estradiol levels in female patients with schizophrenia in China. Methods In the retrospective study, Data were collected and included prolactin, testosterone and estradiol levels of 30 female patients with risperidone monotherapy. In the prospective study, Another 30 female schizophrenic patients were randomized to receive risperidone or adjunctive aripiprazole for six weeks. Serum prolactin, testosterone and estradiol levels were measured. Results Serum prolactin, testosterone and estradiol levels in both studies were significantly decreased after risperidone treatment compared with baseline (P Conclusions Risperidone treatment decreased serum testosterone and estradiol levels. Adjunctive aripiprazole relieved hyperprolactinemia, but had no effect on testosterone or estradiol levels. Adjunctive aripiprazole at a dose of 5 mg is recommended for clinical use.

The purpose of this study was to investigate the potential effects of a meal and grapefruit juice on the pharmacokinetics of blonanserin and its metabolite N-desethyl blonanserin in healthy Chinese volunteers. This was a single-centre, open-label, fixed-sequence study, where 12 healthy Chinese volunteers received a single dose of 8 mg blonanserin after an overnight fast in period 1 (reference), a high-fat meal during period 2 and with co-administration of 250 mL of grapefruit juice in period 3. The washout period was 7 days. Series of plasma samples were collected after each dose to determine concentrations of blonanserin and its metabolite N-desethyl blonanserin using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were estimated by non-compartmental analysis and compared between periods by standard average bioequivalence ANOVA. Adverse events were monitored throughout the study. All subjects completed the study. High-fat meals significantly increased blonanserin exposure (AUCt) 2.58-fold (90% CI 2.21, 3.02), relative to the reference period. Co-administration of blonanserin with grapefruit juice remarkably prolonged elimination half-life of blonanserin (from 9.7 to 21.4 h) and significantly increased exposures to blonanserin and N-desethyl blonanserin by 5.82-fold (90% CI 4.57, 7.42) and 1.81-fold (90% CI 1.65, 1.98), respectively. These results suggested that blonanserin was largely metabolised in the intestinal tract before becoming systemically available, and both food and grapefruit juice enhanced exposure to blonanserin and N-desethyl blonanserin. Grapefruit juice increased bioavailability and may have reduced systemic clearance of blonanserin. Further intestinal CYP3A4 and hepatic CYP3A4 might be postulated to explain the delayed elimination of blonanserin. Dose adjustment of blonanserin is needed on the basis of co-intake of known strong CYP3A4 inhibitor. Patients taking high-dose blonanserin also need to be cautious about the ingestion of grapefruit juice.

What is known and objective Little is known regarding changes in blood coagulation parameters associated with tetracycline antibiotics. We report a possible case of elevated PT, APPT and PT/INR associated with doxycycline and cefoperazone co-administration. Case summary An 83-year-old Chinese male inpatient with severe pneumonia, chronic renal insufficiency and malnutrition experienced elevated PT, APPT and PT/INR which occurred within a few days of doxycycline added to his cefoperazone treatment and returned to normal after removal of it. What is new and conclusion Very close monitoring of coagulation parameters might be advisable in those subjects when administering doxycycline and cefoperazone concomitantly.

1. A new oral liquid formulation combining guaifenesin, pseudoephedrine and hydrocodone is effective in improving the symptoms of common cold. The pharmacokinetic properties of the individual components were evaluated in a randomized, open-label, four-period study in 12 healthy Chinese volunteers following single and multiple doses. The data were compared with data for the individual ingredients in Antuss®. 2. In the single-dose period, exposure levels (AUC and Cmax) for guaifenesin, pseudoephedrine and hydrocodone increased directly as the dose of the oral liquid formulation increased from 5 to 15 mL. Only minor amounts of guaifenesin and hydrocodone were excreted in urine (∼0.10% and 4.66%, respectively). Pseudoephedrine was mainly excreted unchanged, with 44.95% of the dose excreted in urine within 24 h. After multiple dosing, there was no obvious accumulation of any drug, as assessed by AUC. When considering Cmax, there was a trend toward accumulation of hydrocodone and pseudoephedrine. The pharmacokinetic profiles of guaifenesin and pseudoephedrine in the oral liquid formulation were similar to those in the branded preparation, Antuss®. 3. The newly developed oral liquid formulation combining guaifenesin, pseudoephedrine and hydrocodone was safe and well tolerated and might provide a reliable alternative to the branded formulation for patients with common colds.

The rapid, sensitive, and selective liquid chromatography-electrospray ionization-tandem mass spectrometry method (LC-ESI-MS/MS) for the simultaneous estimation and pharmacokinetic investigation of glimepiride and pioglitazone in human plasma has been developed and fully validated. Glimepiride and pioglitazone, compounds which exert synergistic effects on blood glucose control, were investigated in human plasma using deuterium-labeled analogs as internal standards (IS). Liquid-liquid extraction was carried out on 0.2 mL of human plasma using ethyl acetate, and chromatographic separation was performed on an Agilent Eclipse plus C18 column (4.6 mm × 100 mm, 3.5 μm) using a mobile phase consisting of methanol-water-formic acid (95:5:0.1, v/v/v, plus 5mM ammonium acetate) at a flow rate of 0.8 mL/min. To quantify glimepiride, pioglitazone and their IS, multiple reaction monitoring (MRM) transitions of m/z 491.2→352.2, m/z 496.2→357.2, m/z 357.2→134.2 and m/z 361.2→138.2 were performed in positive mode. The total run time was 3.0 min and the elution time was about 2.4 min. The method exhibited good separation of analytes, without interference from endogenous substances. The linear calibration curves were 0.2-250 ng/mL for glimepiride and 0.2-1,250 ng/mL for pioglitazone; the lower limit of quantification (LLOQ) was 0.2 ng/mL for both analytes. Intra- and inter-day reproducibility was less than 10% for glimepiride and less than 5% for pioglitazone, with relative errors ranging from -8.00% to 2.80% at the three concentrations of analytes used for quality control (QC). The matrix effect was negligible and recoveries were similar for each analyte and its IS. Glimepiride and pioglitazone were found to be stable under the assay conditions and the method was successfully applied to the evaluation of pharmacokinetic studies of glimepiride and pioglitazone, following oral doses of 2mg glimepiride tablets and 15 mg pioglitazone tablets to 16 healthy volunteers.

Allopurinol is used widely for the treatment of gout, but its pharmacokinetics is complex and some patients show hypersensitivity, necessitating careful monitoring and improved detection methods. In this study, a sensitive and reliable liquid chromatography-tandem mass spectrometry method was developed to determine the concentrations of allopurinol and its active metabolite oxypurinol in human plasma and urine using 2,6-dichloropurine as the internal standard (IS). Analytes and the IS were extracted from 0.5 ml aliquots of plasma or urine using ethyl acetate and separated on an Agilent Eclipse Plus C18 column using methanol and ammonium formate–formic acid buffer containing 5 mM ammonium formate and 0.1% formic acid (95:5, v/v) as the mobile phase (A) for allopurinol or methanol plus 5 mM ammonium formate aqueous solution (95:5, v/v) as the mobile phase (B) for oxypurinol. Allopurinol was detected in positive ion mode and the analysis time was about 7 min. The calibration curve was linear from 0.05 to 5 μg/mL allopurinol in plasma and 0.5–30 μg/mL in urine. The lower limit of quantification (LLOQ) was 0.05 μg/mL in plasma and 0.5 μg/mL in urine. The intra- and inter-day precision and relative errors of quality control (QC) samples were ≤11.1% for plasma and ≤ 8.7% for urine. Oxypurinol was detected in negative mode with an analysis time of about 4 min. The calibration curve was linear from 0.05 to 5 μg/mL in plasma (LLOQ, 0.05 μg/mL) and from 1 to 50 μg/mL in urine (LLOQ, 1 μg/mL). The intra- and inter-day precision and relative errors were ≤7.0% for plasma and ≤9.6% for urine. This method was then successfully applied to investigate the pharmacokinetics of allopurinol and oxypurinol in humans.

1. Ingestion of grapefruit juice and food could be factors affecting the pharmacokinetics of pirfenidone, a promising drug for treatment of idiopathic pulmonary fibrosis. 2. A randomized, open-label, three-period crossover study was carried out in 12 healthy Chinese male volunteers who were randomized to one of the three treatments: pirfenidone tablets (0.4 g) were orally administered to fasted or fed subjects, or with grapefruit juice. The washout period was 7 d. 3. Significantly reduced maximum plasma concentration (Cmax, 5.0 5 ± 1.39 versus 10.9 0 ± 2.94 mg·L(- 1)), modestly affected area-under-the-plasma concentration-time curve (AUC) from time zero to 12 h post dosing (AUC0-12 h, 21.8 9 ± 6.47 versus 26.1 6 ± 7.32 mg·h·L(- 1)) and delayed time to reach Cmax (Tmax) were observed in fed group compared with fasted group. Similar effects on Cmax (5.8 2 ± 1.23 versus 10.9 0 ± 2.94 mg·L(- 1)) and AUC0-12 h (modest but not statistically significant, 24.4 4 ± 7.40 versus 26.1 6 ± 7.32 mg·h·L(- 1)) were observed for grapefruit juice compared to fasted subjects. 4. Co-administration of pirfenidone with grapefruit juice resulted in modestly reduced overall oral absorption and significantly reduced peak concentrations compared to fasting, which was similar to effect of food ingestion. No adverse events were observed in the study, but relatively dramatic reduction of peak concentrations should raise concerns for clinical efficacy and safety.

Aim: Peramivir is a newly approved selective neuraminidase inhibitor designed to inhibit influenza virus infection. Methodology/results: We report a robust and sensitive method utilizing simple precipitation extraction with LC–MS/MS for the high-throughput quantification. Addition of 0.06 M of ammonium formate and 0.1% formic acid in mobile phase could help reduce the matrix effect. This method uses 100 µl of plasma and covers a linear concentration range from 5 to 10,000 ng/ml. Other validation parameters are also evaluated and meet regulatory expectations by US FDA guidelines. Conclusion: The developed HPLC–MS/MS method has been successfully applied to support a clinical pharmacokinetic study. The strategy presented here can be applied elsewhere and may be useful for other amphiphilic drugs.