Analyzing the correlation between quinolone-resistant Escherichia coli resistance rates and climate factors: A comprehensive analysis across 31 Chinese provinces.

BACKGROUND: The increasing problem of bacterial resistance, particularly with quinolone-resistant Escherichia coli (QnR eco) poses a serious global health issue. METHODS: We collected data on QnR eco resistance rates and detection frequencies from 2014 to 2021 via the China Antimicrobial Resistance Surveillance System, complemented by meteorological and socioeconomic data from the China Statistical Yearbook and the China Meteorological Data Service Centre (CMDC). Comprehensive nonparametric testing and multivariate regression models were used in the analysis. RESULT: Our analysis revealed significant regional differences in QnR eco resistance and detection rates across China. Along the Hu Huanyong Line, resistance rates varied markedly: 49.35 in the northwest, 54.40 on the line, and 52.30 in the southeast (P = 0.001). Detection rates also showed significant geographical variation, with notable differences between regions (P < 0.001). Climate types influenced these rates, with significant variability observed across different climates (P < 0.001). Our predictive model for resistance rates, integrating climate and healthcare factors, explained 64.1% of the variance (adjusted R-squared = 0.641). For detection rates, the model accounted for 19.2% of the variance, highlighting the impact of environmental and healthcare influences. CONCLUSION: The study found higher resistance rates in warmer, monsoon climates and areas with more public health facilities, but lower rates in cooler, mountainous, or continental climates with more rainfall. This highlights the strong impact of climate on antibiotic resistance. Meanwhile, the predictive model effectively forecasts these resistance rates using China's diverse climate data. This is crucial for public health strategies and helps policymakers and healthcare practitioners tailor their approaches to antibiotic resistance based on local environmental conditions. These insights emphasize the importance of considering regional climates in managing antibiotic resistance.

Metabolic activation of tyrosine kinase inhibitors: recent advance and further clinical practice.

At present, receptor tyrosine kinase signaling-related pathways have been successfully mediated to inhibit tumor proliferation and promote anti-angiogenesis effects for cancer therapy. Tyrosine kinase inhibitors (TKIs), a group of novel chemotherapeutic agents, have been applied to treat diverse malignant tumors effectively. However, the latent toxic and side effects of TKIs, such as hepatotoxicity and cardiotoxicity, limit their use in clinical practice. Metabolic activation has the potential to lead to toxic effects. Numerous TKIs have been demonstrated to be transformed into chemically reactive/potentially toxic metabolites following cytochrome P450-catalyzed activation, which causes severe adverse reactions, including hepatotoxicity, cardiotoxicity, skin toxicity, immune injury, mitochondria injury, and cytochrome P450 inactivation. However, the precise mechanisms of how these chemically reactive/potentially toxic species induce toxicity remain poorly understood. In addition, we present our viewpoints that regulating the production of reactive metabolites may decrease the toxicity of TKIs. Exploring this topic will improve understanding of metabolic activation and its underlying mechanisms, promoting the rational use of TKIs. This review summarizes the updated evidence concerning the reactive metabolites of TKIs and the associated toxicities. This paper provides novel insight into the safe use of TKIs and the prevention and treatment of multiple TKIs adverse effects in clinical practice.

Effects of Trough Concentration and Solute Carrier Polymorphisms on Imatinib Efficacy in Chinese Patients with Chronic Myeloid Leukemia.

PURPOSE: We investigated the relationship between imatinib trough concentrations and genetic polymorphisms with efficacy of imatinib in Chinese patients with chronic myeloid leukemia (CML). METHODS: There were 171 eligible patients. Peripheral blood samples were collected from 171 eligible patients between 21 and 27 hours after the last imatinib administration. Complete cytogenetic response (CCyR), major molecular response (MMR) and complete molecular response (CMR) were used as metrics for efficacy. Nine single nucleotide polymorphisms in 5 genes, SLC22A4 (917 T>C, -248 C>G and -538 C>G), SLC22A5 (-945 T>G and -1889 T>C), SLCO1A2 (-361 G>A), SLCO1B3 (334 T>G and 699 G>A) and ABCG2 (421C>A) were selected for genotyping. RESULTS: Patients with CCyR achieve higher trough concentrations than those without CCyR (1478.18±659.83 vs 984.89±454.06 ng mL-1, p<0.001). Patients with MMR and CMR achieve higher trough concentrations than those without MMR and CMR, respectively (1486.40±703.38 vs 1121.17±527.14 ng mL-1, p=0.007; 1528.00±709.98 vs 1112.67±518.35 ng mL-1, p=0.003, respectively). Carriers of A allele in SLCO1A2 -361G>A achieve higher CCyR and MMR rates (p=0.047, OR=4.320, 95% CI: 0.924-20.206; p=0.042, OR=2.825, 95% CI: 1.016-7.853, respectively). Both trough concentrations and SLCO1A2 -361G>A genotypes are independent factors affecting imatinib efficacy. The positive and negative predictive values for CCyR are 71.01% and 68.75%, respectively. The positive and negative predictive values for MMR are 62.86% and 69.70%, respectively. CONCLUSION: Imatinib trough concentrations and SLCO1A2 -361G>A genotypes are associated with imatinib efficacy in Chinese patients with CML.

Effects of Differential Food Patterns on the Pharmacokinetics of Enteric-Coated Mesalazine Tablets in the Same Cohort of Healthy Chinese Volunteers.

This study aimed to simultaneously determine mesalazine (5-ASA) and its major metabolite N-Ac-5-ASA in the plasma and to evaluate the impact of different food patterns on the relative bioavailability and pharmacokinetics of a single oral dose of 5-ASA in healthy subjects. In this single-dose, open-label, 3-period, 3-treatment crossover study, the subjects received a single, oral dose of 500-mg enteric-coated mesalazine tablet together with either a low-fat or a high-fat breakfast or under fasting condition (reference). The pharmacokinetic parameters were determined by noncompartmental methods and analyzed with a linear mixed-effect model. The geometric least squares mean ratio for the area under the plasma concentration-time curve from zero to infinity of N-Ac-5-ASA was 1.05 (90% confidence interval [CI], 0.70-1.58) for high-fat/fasted condition and 1.06 (90%CI, 0.82-1.36) for low-fat/fasted condition. The least squares mean ratio of 5-ASA was 0.86 (90%CI, 0.65-1.14) for high-fat/fasted condition and 0.78 (90%CI, 0.60-1.02) for low-fat/fasted condition. All P values were >.05. The mean maximum plasma concentration and the time to reach the maximum plasma concentration of N-Ac-5-ASA were 2084 ng/mL, 8 hours; 2639 ng/mL, 11 hours, and 2409 ng/mL, 9 hours for fasted, high-fat, and low-fat, respectively. The values of 5-ASA were 1950 ng/mL, 7 hours; 2869 ng/mL, 9 hours; and 2837 ng/mL, 8 hours for fasted, high-fat, and low-fat condition. 5-ASA was well tolerated under all 3 conditions. Food delayed the absorption of 5-ASA, especially a high-fat meal. Therefore, enteric-coated mesalazine tablets should be taken before meals to avoid causing patients slow response and any effect of food on its efficacy.

Effects of licorice extracts on the pharmacokinetics of brucine in rats and its possible mechanism.

The detoxification effects of licorice are believed to be related to its pharmacokinetic (PK) interference. This paper aimed to evaluate the effects of licorice water extracts (LWE) on the pharmacokinetics of brucine. Rats were administered brucine and/or LWE. The pharmacokinetic behavior of brucine and bioactive components of licorice were quantified by HPLC-MS/MS. P-glycoprotein (P-gp) inhibitor verapamil, real time PCR, vesicular transport assay and everted gut sacs were employed to investigate its possible mechanism. We found LWE reduced the Cmax and AUC of oral brucine in a dose-dependent way. In contrast, the AUC values of intraperitoneal brucine showed no significant difference between LWE treated and untreated rats, which indicating the intestinal absorption of brucine was influenced by LWE. We found that high dose of LWE activated the transport activity of P-gp in vesicular transport assay, while the mRNA level of P-gp in the intestinal was not affected by licorice. Moreover, high dose of LWE decreased the intestinal absorption of brucine in the everted gut sacs model, which could over turned by verapamil. These results suggested that a single high dose of LWE could impair the intestine absorption of brucine, and its potential mechanism may be mediated by P-gp in intestine.

Licorice Extracts Attenuate Nephrotoxicity Induced by Brucine Through Suppression of Mitochondria Apoptotic Pathway and STAT3 Activation.

Licorice, one of the most widely used medicinal herbs in East Asia, has effects such as anti-inflammation, antioxidant, and detoxifying. This study aimed to evaluate the protective effect of licorice on brucine-induced nephrotoxicity. Sprague Dawley rats were administered with brucine intraperitoneally for 7 consecutive days with or without treatment with licorice. The content of blood urea nitrogen and creatinine in serum, the activities of superoxide dismutase and content of glutathione, malonaldehyde in kidney tissue were detected. Hematoxylin-eosin staining was employed to observe the histopathological changes of kidney. The expression and phosphorylation levels of protein were evaluated by Western blotting and immunohistochemical analysis. The results illustrated that treatment with licorice extracts (LE) significantly protected against the brucine-induced nephrotoxicity by reducing the content of blood urea nitrogen and serum creatinine, attenuating pathologic damage. The unbalance of oxidative stress was repaired by LE via increasing the level of glutathione, promoting the activities of superoxide dismutase and decreasing the content of malonaldehyde. In addition, LE overturned the influence of brucine on apoptosis-related protein and signal transducer and activator of transcription-3 (STAT3) activation. Taken together, these data demonstrate that licorice may attenuate brucine-induced nephrotoxicity via inactivation of oxidative stress and mitochondrial-mediated apoptosis pathway. More importantly, the renoprotective effects may be mediated, at least partly, by preventing the activation of STAT3 protein.

Population pharmacokinetic and pharmacogenetics of imatinib in Chinese patients with chronic myeloid leukemia.

AIM: This study aimed to establish a population pharmacokinetic (PPK) model in Chinese patients with chronic myeloid leukemia, and to quantify the effects of pharmacogenetics on pharmacokinetic parameters of imatinib. METHODS: A total of 229 plasma concentrations from 170 patients were analyzed. Nonlinear mixed effect model was used to establish the PPK model. RESULTS: A one-compartment model with first-order absorption and first-order elimination adequately describes imatinib pharmacokinetics. Actual bodyweight shows slight effect on the estimated apparent clearance (CL/F) of imatinib in this study population. The final PPK model is: Ka (1/h) = 0.329; CL/F (l/h) = 9.25 × (actual bodyweight/70)0.228; V/F(l) = 222. CONCLUSION: Actual bodyweight has a slight effect on CL/F. Demographics, physiopathology and pharmacogenetics covariates have no significant effects on imatinib pharmacokinetics.

Effect of aprepitant administration on CINV caused by cisplatin multi-day chemotherapy and pharmacokinetics of docetaxel.

PURPOSE: To compare efficacy and safety of postponing administration of aprepitant and routine triple-antiemetic treatment for chemotherapy-induced nausea and vomiting in patients who received docetaxel and cisplatin multi-day chemotherapy treatment, and to evaluate the effect of aprepitant on docetaxel pharmacokinetics in the Chinese population. METHODS: A total of 24 cancer patients (including 5 females and 19 males, 22-74 years old) received two cycles of high-emetic DP (docetaxel 75 mg/m2 on day 1 + cisplatin 25 mg/m2 on days 1-3) regimen. A randomized, two-period and cross-over study was applied for prevention of chemotherapy-induced nausea and vomiting. The patients in group A took aprepitant 125 mg on day 1 and 80 mg on days 2-3 (administered aprepitant 1 h before chemotherapy). In group B, the patients took aprepitant 125 mg on day 2, 80 mg on days 3-4, which was delayed 1 day than group A. Efficacy and safety in overall phase were evaluated within 5 days after initiation of chemotherapy. Simultaneously, the differences in the pharmacokinetic parameters of docetaxel between two different antiemetic treatments are compared. RESULTS: The CR rate of delayed-phase nausea was compared between the routine triple-antiemetic treatment (group A) and the aprepitant delayed 1-day administration treatment (group B), and the difference was statistically significant (16.7% vs 45.8% P < 0.05), despite there were similar for two groups in the CR rate of acute-phase nausea and vomiting, and delayed-phase vomiting. In two groups, the area under the docetaxel curve (AUC0-t values) (mean ± SD) of docetaxel was 1134.21 ± 732.55 (ng h/mL) and 1080.94 ± 585.09 (ng h/mL), and the geometric means were 944.82 and 902.10 (ng h/mL), respectively. There was no significant difference in AUC values between the two antiemetic treatments (P > 0.05), as well as Cmax, CLz, T1/2z, MRT and Tmax. CONCLUSIONS: Delayed administration of aprepitant provided superior delayed-phase nausea protection for patients who received cisplatin-based chemotherapy in comparison with the routine triple-antiemetic treatment. In addition, in the routine triple-antiemetic treatment, aprepitant did not significantly affect the main pharmacokinetic parameters of docetaxel.

Simple and rapid UPLC-MS/MS method for quantification of entecavir in human plasma: Application to a bioequivalence study
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A simple and fast ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated to determine entecavir in human plasma with the stable isotopically labeled internal standard entecavir-13C215N. Samples (100 µL each) were pretreated by protein precipitation with methanol, and then separated on an ACQUITY UPLC BEH C18 analytical column (2.1 × 50 mm, 1.7 µm) with a simple isocratic elution. The detection was operated by a positive ionization electrospray mass spectrometry in multiple reaction monitoring mode. The method had a short chromatographic run time of 2 minutes, and obtained sharp peaks of entecavir and the internal standard. Good linearity was found within 0.1 - 20 ng/mL. The intra- and inter-day precision and accuracy met the acceptance criteria, and no matrix effect was observed. This method was successfully applied in a bioequivalence study of two kinds of entecavir tablets in healthy Chinese volunteers. And the results showed that no significant differences were found between the test and reference preparations in pharmacokinetic parameters (p > 0.05) by ANOVA. The 90% confidence intervals for the geometric mean ratios (test/reference) of Cmax, AUC0-tlast, and AUC0-∞ fell within the bioequivalence acceptance criteria (80 - 125%). No significant difference was found in tmax between the two preparations. The two one-sided t-tests showed that these two products were bioequivalent.
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An LC-MS/MS method for determination of bioactive components of liquorice and Semen Strychni in rat plasma: Application to a pharmacokinetics study.

Semen Strychni is known for its treatment of rheumatic arthritis with a low therapeutic index. Liquorice contributes a lot in herb detoxification according to the traditional Chinese medicine theory. A simple, rapid, and sensitive liquid chromatography-mass spectrometric method (LC-MS) was developed and validated for simultaneous determination of main bioactive ingredients in liquorice and Semen Strychni in rat plasma. Using moclobemide and cyproterone acetate as the internal standards, the analytes were pretreated via protein precipitation with methanol. An Ultimate AQ-C18 column (3.0 µm, 3.0 × 100 mm) was employed for chromatographic separation, combining with gradient elution. The mobile phase consisted of 0.07% formic acid and 0.12% ammonium acetate in aqueous phase (A) and acetonitrile in organic phase (B). The elution program was as follows: 0-0.5 min, 20% B; 0.5-1 min, 20-60% B; 1-7 min, 60-85% B; and 7-7.5 min, returned to 20% B, then continued to 12 min. Selected reaction monitoring was performed in both positive and negative ESI. Positive mode was adopted for detection of strychnine, brucine, and moclobemide, while negative mode was used for glycyrrhizic acid, glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, liquiritin, and cyproterone acetate. The method was validated for specificity, linearity, matrix effect, recovery, precision, accuracy, and stability. The results show that this method is sensitive, accurate and robust for biological matrix analysis. Moreover, the proposed method was applied to a pharmacokinetic study in Sprague-Dawley rats for investigating the mechanism of which liquorice detoxifies Semen Strychni.

Pharmacokinetics and relative bioavailability of a generic amisulpride tablet in healthy Chinese volunteers
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OBJECTIVE: To assess and compare the pharmacokinetic properties and bioavailability of a newly developed formulation of amisulpride with those of a conventional formulation in healthy Chinese volunteers under fasting state. MATERIALS AND METHODS: A single-dose, two-sequence crossover study was designed. 20 healthy subjects (14 males and 6 females) were randomized into two groups. A single oral dose of amisulpride (200 mg) was given after an overnight fast of 12 hours. Blood samples were taken at scheduled time spots and separated by a washout period of 14 days. Plasma concentration of amisulpride was measured by high-performance liquid chromatography-fluorescence detector (HPLC-FLD) method. RESULTS: The pharmacokinetic parameters of AUC0-tlast, AUC0-∞, and Cmax for the 20 subjects after a single oral dose of the trial preparation or the reference preparation were 4,767.2 and 4,856.3 ng×h×mL-1; 4,891.7 and 5,043.2 ng×h×mL-1; 584.7 and 586.3 ng×mL-1, respectively. The relative bioavailability was 98.9 ± 14.5%. No significant difference was found among the main pharmacokinetic parameters in the two preparations by ANOVA. The 90% confidence intervals for the geometric mean ratios (test/reference) of Cmax and AUC0-tlast were 90.7 - 109.1% and 92.5 - 103.6%, respectively, meeting the predetermined criteria (80 - 125%) for bioequivalence. No serious adverse events were reported. CONCLUSION: The study demonstrated that the two preparations met the regulatory criteria for bioequivalence and both formulations were well tolerated.
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Association Between Vancomycin Blood Brain Barrier Penetration and Clinical Response in Postsurgical Meningitis.

PURPOSE: This study investigated the association between vancomycin blood brain barrier penetration and clinical response in patients with postsurgical meningitis. METHODS: Adult patients with postsurgical meningitis were recruited. Eligible patients received vancomycin 500 mg every 6 h for at least 5 days. On day 3 or 4, cerebrospinal fluid (CSF) and simultaneous serum samples were obtained to determine CSF minimum concentrations (Cmin), serum Cmin and CSF to serum Cmin ratio. RESULTS: Twenty-two patients (14 men and 8 women; mean age of 52.6± 12.1 years) were recruited. The vancomycin Cmin was 3.63 ± 1.64 mg/L in CSF and 13.38 ± 5.36 mg/L in serum, with the CSF to serum Cmin ratio of 0.291 ± 0.118. The Cmin in serum and in CSF showed a significant correlation (p=0.005, r =0.575). The vancomycin CSF Cmin had a significant correlation with the decline of white blood cell counts (WBCs) in CSF (p=0.003, r =0.609). CSF Cmin, serum Cmin and CSF to serum Cmin ratio all showed no significant correlation with clinical response (p=0.335, 0.100, 0.679, respectively). CONCLUSIONS: There was a positive correlation between serum Cmin and CSF Cmin. However, only CSF Cmin is positively correlated with WBCs improvement in CSF. All other parameters such as serum Cmin, CSF Cmin and CSF to serum Cmin ratio had no correlation with clinical response. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Pharmacokinetics and relative bioavailability of two allopurinol tablets in healthy Chinese volunteers
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OBJECTIVE: To evaluate the pharmacokinetics and relative bioavailability of two allopurinol tablets in healthy Chinese volunteers. METHODS: A single-center, randomized, cross-over, two-period study design was conducted in healthy male subjects who were identified as not carrying the HLA-B*58:01 allele. Under fasting conditions, a single oral dose of 300 mg test or reference tablets was given with a 1-week washout period. The blood samples were collected for up to 12 hours after the administration and the plasma concentrations of allopurinol were determined by high performance liquid chromatography. Subject interviews and physical examinations were done over regular intervals to monitor the adverse events. RESULTS: 18 subjects were enrolled in the study, and none dropped out. The main pharmacokinetic parameters of allopurinol test and reference preparations were as follows: AUC0-tlast was 6,725.1 ± 1,390.0 ng×h×mL-1 and 6,425.6 ± 1,257.6 ng×h×mL-1; AUC0-∞ was 7,069.1 ± 1,503.2 ng×h×mL-1 and 6,750.6 ± 1,347.7 ng×h×mL-1; tmax was 1.3 ± 0.8 hours and 1.3 ± 0.8 hours; Cmax was 2,203.7 ± 557.4 ng×mL-1 and 2,310.8 ± 662.8 ng×mL-1; and T1/2 was 2.0 ± 1.6 hours and 1.7 ± 0.7 hours. The relative bioavailability was 105.1 ± 12.6%. The 90% confidence intervals for the geometric mean ratios (test/reference) of Cmax, AUC0-tlast, and AUC0-∞ of both preparations fell within the bioequivalence acceptance criteria (80 - 125%). No adverse events were found or reported during the study. CONCLUSION: The test allopurinol preparations and the reference preparations are bioequivalent and both are well tolerated.
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Quantitative analysis of valsartan by two-dimensional liquid chromatography (2D-HPLC) and its application in a bioequivalence study in Chinese volunteers
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PURPOSE: To develop a sensitive, two-dimensional liquid chromatography (2D-LC) method for determination of valsartan, applied to investigate bioequivalence of two valsartan tablets in Chinese volunteers under fasting condition. METHODS: A full automatic 2D-HPLC system was used to quantify valsartan in human plasma. The analytes were extracted by protein precipitation, using telmisartan as internal standard. The analytical method was applied in a randomized, crossover bioequivalence study of valsartan tablets; the study enrolled 18 Chinese volunteers (12 were men and 6 were women). The subjects received a single 160-mg dose of test or reference preparation with 7-days of washout under fasting state. Plasma samples were collected, pharmacokinetic parameters were obtained and the bioequivalence was evaluated. RESULTS: The calibration range was 9.2 - 4213.8 ng×mL-1. Inter- and intraprecision was less than 7.0%, and accuracies ranged from 99.5 to 103.8%. The extraction recovery for valsartan varied between 89.3 and 97.8%, and the stability in all conditions was excellent. The 90% CI of AUC0→36h and Cmax were 96.5 - 109.4% and 94.2 - 108.6%, respectively. The relative bioavailability was 103.9 ± 15.7%. No gender difference was observed in pharmacokinetic parameters. CONCLUSIONS: A sensitive 2D-HPLC method was established for the estimation of valsartan in human plasma and successfully applied in a bioequivalence study of valsartan, which suggests that these two formulations can be assumed to be bioequivalent.
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A sensitive LC-MS/MS method for analysis of pericyazine in presence of 7-hydroxypericyazine and pericyazine sulphoxide in human plasma and its application to a comparative bioequivalence study in Chinese healthy volunteers.

A robust and highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of pericyazine in human plasma. The plasma sample was alkalized with sodium hydroxide solution and handled by liquid-liquid extraction with ethyl acetate after adding perphenazine as an internal standard (IS). The analytes were separated on an Ultimate™ AQ-C18 analytical column at 40°C, with a gradient elution consisting of A (aqueous phase: 5mM ammonium acetate buffer solution containing 0.1% formic acid) and B (organic phase: acetonitrile) at a flow rate of 0.350mL/min. The detection was conducted on an API 4000 tandem mass spectrometer coupled with electrospray ionization (ESI) source in positive ion mode. The multiple reaction monitoring (MRM) transitions, m/z 366.5>142.4 for pericyazine, m/z 382.5>142.4 for its 7-hydroxy and sulphoxide metabolites and m/z 404.3>171.3 for IS were chosen to achieve high selectivity in the simultaneous analyses. The method exhibited great improvement in sensitivity (LLOQ of 0.021ng/mL) and good linearity over the concentration range of 0.021-9.90ng/mL. The intra- and inter-day precision, accuracy, and stability results were within the acceptable limits and no matrix effect was observed. This method was successfully applied in a bioequivalence study to evaluate the pharmacokinetics in 20 healthy male Chinese volunteers. Additional exploratory analyses of 7-hydroxy and sulphoxide metabolites of pericyazine in the same samples suggest that the unchanged drug is predominant in the plasma and suitable for the bioequivalence comparison after a single oral administration of 10mg pericyazine.

A validated UPLC-MS/MS method for simultaneous determination of imatinib, dasatinib and nilotinib in human plasma.

A sensitive, rapid, simple and economical ultra-performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was developed and validated for simultaneous determination of imatinib, dasatinib and nilotinib in human plasma using gliquidone as internal standard (IS). Liquid-liquid extraction method with ethyl acetate was used for sample pre-treatment. The separation was performed on an Xtimate Phenyl column using isocratic mobile phase consisting of A (aqueous phase: 0.15% formic acid and 0.05% ammonium acetate) and B (organic phase: acetonitrile) (A:B=40:60, v/v). The flow rate was 0.25 mL/min and the total run time was 6 min. The multiple reaction monitoring (MRM) transitions, m/z 494.5→394.5 for imatinib, 488.7→401.5 for dasatinib, 530.7→289.5 for nilotinib and 528.5→403.4 for IS, were chosen to achieve high selectivity in the simultaneous analyses. The method exhibited great improvement in sensitivity and good linearity over the concentration range of 2.6-5250.0 ng/mL for imatinib, 2.0-490.0 ng/mL for dasatinib, and 2.4-4700.0 ng/mL for nilotinib. The method showed acceptable results on sensitivity, specificity, recovery, precision, accuracy and stability tests. This UPLC-MS/MS assay was successfully used for human plasma samples analysis and no significant differences were found in imatinib steady-state trough concentrations among the SLC22A5 -1889T>C or SLCO1B3 699G>A genotypes (P>0.05). This validated method can provide support for clinical therapeutic drug monitoring and pharmacokinetic investigations of these three tyrosine kinase inhibitors (TKIs).

Bioequivalence and food effect study of enteric-coated mesalazine tablets in healthy Chinese volunteers by HPLC-ESI-MS/MS.

OBJECTIVE: To establish a developed HPLC-ESI-MS/MS method for simultaneous determination of mesalazine (5-ASA) and its major metabolite N-Ac-5-ASA in human plasma and to investigate bioequivalence of two enteric-coated mesalazine tablets as well as the effect of high-fat food on the pharmacokinetics of 5-ASA and N-Ac-5-ASA. METHODS: In this open-label, randomized, crossover, two-states, four-period study, 20 healthy Chinese volunteers were randomized to receive a single oral dose of trial or reference preparation (2 × 250 mg) under fasting and fed state. Plasma samples were obtained at 0, 1, 2, 3, 4, 4.5, 5, 5.5, 6, 6.5, 7, 8, 10, 12, 24, and 36 hours postdose and were measured by a developed HPLC-ESI-MS/MS method. Safety and tolerability were assessed throughout the study. RESULTS: The HPLC-ESI-MS/MS method required only 7.0 minutes run time and was successfully applied in analyzing ~ 2,000 samples. High-fat-food administration prolonged tmax of 5-ASA and N-Ac-5-ASA (p < 0.05), while AUC was not significantly affected by the meal (p > 0.05). The 90% confidence intervals (CIs) of the fed/fasting and trial/reference ratios of log-transformed Cmax and AUC were within 80-125%. The two one-sided t-tests showed that the trial and reference preparation were bioequivalent (p > 0.05). CONCLUSIONS: This developed HPLC-ESI-MS/MS method is suitable for massive biomedical analysis. Trial and reference preparations are bioequivalent under fasting and fed state. High-fat-food administration delays the absorption of mesalazine while total exposure is not affected. Dietary habits should always be taken into consideration when enteric-coated mesalazine tablets were prescribed to patients.

Pharmacokinetic properties and bioequivalence of spironolactone tablets in fasting and fed healthy Chinese male subjects.

BACKGROUND AND PURPOSE: Spironolactone is a potassium-sparing diuretic and is a competitive antagonist of aldosterone, which is widely used in the treatment of primary aldosteronism, essential hypertension, congestive cardiac failure, and various edematous states. The purpose of this study was to compare the pharmacokinetic properties and bioequivalence of the two formulations of spironolactone tablets in healthy Chinese male subjects under fasting and fed condition. METHODS: A total of 40 male subjects were enrolled in this randomized, open-label, two-period crossover study, subjects in 2 groups (20 individuals in each group) received a single 100-mg dose of test or reference spironolactone tablet formulations with a 2-week washout period under both fasting and fed condition. The plasma concentrations of canrenone, a major active metabolite of spironolactone, were quantified by a validated high performance liquid chromatography-tandem mass spectrometry method. The pharmacokinetic parameters including AUC0-tlast, AUC0-∞, tmax, and Cmax were employed to test bioequivalence. RESULTS: The relative bioavailability was 99.2 ± 11.6% and 97.6 ± 7.4% under fasting and fed condition, respectively. The 90% confidence intervals of the adjusted geometric mean ratio (test/reference) of Cmax, AUC0-tlast, and AUC0-∞ were 89.7-113.8%, 93.9-103.3%, and 90.0-103.0% in fasting study and 87.7-102.3%, 95.1-99.5%, and 94.1-98.9% in fed study, respectively. CONCLUSIONS: Based on pharmacokinetic parameters and the Chinese Food and Drug Administration's guidance and regulatory criteria for bioequivalence, the test and reference formulations of spironolactone were bioequivalent under both fasting and fed condition. Both formulations were generally well tolerated, with no adverse reaction reported.

Long Chain Omega-3 Polyunsaturated Fatty Acid Supplementation Alleviates Doxorubicin-Induced Depressive-Like Behaviors and Neurotoxicity in Rats: Involvement of Oxidative Stress and Neuroinflammation.

Doxorubicin (DOX) is a chemotherapeutic agent widely used in human malignancies. Its long-term use can cause neurobiological side-effects associated with depression. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs), the essential fatty acids found in fish oil, possess neuroprotecitve and antidepressant activities. Thus, the aim of this study was to explore the potential protective effects of ω-3 PUFAs against DOX-induced behavioral changes and neurotoxicity. ω-3 PUFAs were given daily by gavage (1.5 g/kg) over three weeks starting seven days before DOX administration (2.5 mg/kg). Open-field test (OFT) and forced swimming test (FST) were conducted to assess exploratory activity and despair behavior, respectively. Our data showed that ω-3 PUFAs supplementation significantly mitigated the behavioral changes induced by DOX. ω-3 PUFAs pretreatment also alleviated the DOX-induced neural apoptosis. Meanwhile, ω-3 PUFAs treatment ameliorated DOX-induced oxidative stress in the prefrontal cortex and hippocampus. Additionally, gene expression of pro-inflammatory cytokines, including IL-1ß, IL-6, and TNF-α, and the protein levels of NF-κB and iNOS were significantly increased in brain tissues of DOX-treated group, whereas ω-3 PUFAs supplementation significantly attenuated DOX-induced neuroinflammation. In conclusion, ω-3 PUFAs can effectively protect against DOX-induced depressive-like behaviors, and the mechanisms underlying the neuroprotective effect are potentially associated with its anti-oxidant, anti-inflammatory, and anti-apoptotic properties.

Simultaneous Quantification of 25-Hydroxyvitamin D3 and 24,25-Dihydroxyvitamin D3 in Rats Shows Strong Correlations between Serum and Brain Tissue Levels.

While vitamin D3 is recognized as a neuroactive steroid affecting both brain development and function, efficient analytical method in determining vitamin D3 metabolites in the brain tissue is still lacking, and the relationship of vitamin D3 status between serum and brain remains elusive. Therefore, we developed a novel analysis method by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to simultaneously quantify the concentrations of 25-hydroxyvitamin D3 (25(OH)D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) in the serum and brain of rats fed with different dose of vitamin D3. We further investigated whether variations of serum vitamin D3 metabolites could affect vitamin D3 metabolite levels in the brain. Serum and brain tissue were analyzed by HPLC-MS/MS with electrospray ionization following derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD). The method is highly sensitive, specific, and accurate to quantify 25(OH)D3 and 24,25(OH)2D3 in animal brain tissue. Vitamin D3 metabolites in brain tissue were significantly lower in rats fed with a vitamin D deficiency diet than in rats fed with high vitamin D3 diet. There was also a strong correlation of vitamin D3 metabolites in serum and brain. These results indicate that vitamin D3 status in serum affects bioavailability of vitamin D3 metabolites in the brain.