Pharmacokinetics Of Single Oral Dose Research Articles

Single intravenous and oral dose pharmacokinetics of the antiseizure medication brivaracetam in healthy cats.

The number of available antiseizure medications with demonstrated efficacy in cats is limited. As such, there is a need to evaluate the pharmacokinetics of newer medications so that proper dosing regimens can be made. Brivaracetam (BRV) is a more potent analogue of levetiracetam, and is Food and Drug Administration approved for use in people. The goal of this study was to describe the pharmacokinetics of intravenous and oral doses of BRV in healthy cats. A cross-over study involving eight healthy cats, that were administered 10 mg of BRV intravenously as a bolus and orally in the fasted state. Blood samples were collected over 24 h. Analysis was performed using liquid chromatography-mass spectrometry. Data were subjected to non-compartmental analysis. Median (min-max) of maximal concentration, time to maximal concentration, area under the curve, elimination half-life and oral absolute bioavailability were 902 (682-1036) ng/mL, 0.6 (0.5-2.0) h, 6.4 (5.2-7.2) h, 8145 (6669-9351) ng × h/mL and 100% (85-110) respectively. BRV appeared to be well tolerated by all cats. A single dose of BRV is well tolerated both orally and intravenously. Maximal concentrations are produced rapidly and within the human reference interval considered to be therapeutic.

Abstract CT131: Effect of rivoceranib administered as 200 mg once daily on the pharmacokinetics of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 substrates

Abstract Title: Effect of Rivoceranib Administered as 200 mg Once Daily on the Pharmacokinetics of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 Substrates Background: Rivoceranib is a selective vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor with potent antitumor activity. The purpose of this study is to evaluate the effect of rivoceranib on the pharmacokinetics of various CYP substrates in healthy subjects following administration of rivoceranib 200 mg once daily (QD), which is similar to the proposed rivoceranib dosing regimen (250 mg QD) in combination with camrelizumab for the treatment of hepatocellular carcinoma. Methods: This open-label, fixed-sequence, crossover drug-drug interaction phase 1 study evaluated the impact of multiple oral doses of rivoceranib at 200 mg QD on the pharmacokinetics of single oral doses of CYP enzyme substrates included in the Cooperstown 5+1 cocktail (midazolam 2 mg [CYP3A4/5 substrate], warfarin 10 mg [CYP2C9 substrate]/vitamin K 10 mg, dextromethorphan 30 mg [CYP2D6 substrate], omeprazole 40 mg [CYP2C19 substrate], and caffeine 200 mg [CYP1A2 substrate]). On Day 1, subjects received a single oral dose of the Cooperstown cocktail. Blood samples were collected predose on Day 1 and up to 120 hours post-dose for pharmacokinetic analyses. On Days 6-15, subjects received rivoceranib at 200 mg QD. On Day 11, a single dose of the Cooperstown Cocktail was co-administered with rivoceranib at 200 mg. Each dose was administered under postprandial conditions except for Day 11 when subjects fasted. Blood samples were collected predose on Day 11 and up to 120 hours post cocktail dosing for pharmacokinetic analyses. Subjects returned on any day between Days 21-25 for safety follow-up. Results: Rivoceranib 200 mg QD increased dextromethorphan AUC0-inf by 144% and Cmax by 70%, increased midazolam AUC0-inf by 65% and Cmax by 16%, increased the warfarin AUC0-inf by 28% and Cmax by 5%, increased omeprazole AUC0-inf by 77% and Cmax by 62%, and decreased caffeine AUC0-inf by 20% and Cmax by 7%. Cooperstown Cocktail alone or coadministration of Cooperstown Cocktail and rivoceranib was generally well tolerated. Conclusions:Rivoceranib at 200 mg QD does not substantially affect the exposure of the substrates of CYP3A4/5, CYP2C9, CYP2C19, and CYP1A2. Recommendation of dose adjustment of these CYP substrates is not needed when administered with rivoceranib at 200 mg QD. Rivoceranib may increase the exposure of the substrate of CYP2D6 by approximately 100%, indicating that a dose adjustment of CYP2D6 substrates and/or close monitoring patients should be considered when administered with rivoceranib 200 mg QD. Citation Format: Seong Jang, Xiaohui (Tracey) Wei, Xianzhang Meng, Joseph Reitano, Vinoo Urity, Cheol Hee Park, Bill Strickland, Grace Lee, David Nguyen. Effect of rivoceranib administered as 200 mg once daily on the pharmacokinetics of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 substrates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT131.

Safety, Tolerability, and Pharmacokinetics of Single and Multiple Ascending Oral Doses of Youkenafil Hydrochloride, a Phosphodiesterase Type 5 Inhibitor, in Healthy Chinese Male Volunteers.

Youkenafil hydrochloride is a novel selective phosphodiesterase type 5 inhibitor for the treatment of erectile dysfunction. Its safety, tolerability, and pharmacokinetics were evaluated in healthy Chinese male volunteers. In addition, this study explored the effect of food on the pharmacokinetic parameters of youkenafil hydrochloride. The study was divided into 3 trials: a single ascending dose (25, 50, 100, 150, or 200 mg youkenafil), multiple dose (50, 100, or 150 mg youkenafil once daily for 7 consecutive days), and food effect (50 mg youkenafil single dose). The overall tolerability of youkenafil was good. Youkenafil was rapidly absorbed after a single oral dose. Food intake impeded absorption efficiency but had no significant effect on area under the plasma concentration-time curve values. The mean accumulation ratio in area under the plasma concentration-time curve and maximum plasma concentration ranged from 1.3 to 1.6 and from 1.2 to 1.4 after once-daily dosing. There was no apparent accumulation following consecutive administration for 7 days. Less than 1% of the dose was found in urine as the intact drug for all dose groups. Single-dose youkenafil up to 200 mg and multiple doses up to 150 mg were generally safe and well tolerated.

Safety, Tolerability and Pharmacokinetics of Single Ascending and Multiple Oral Doses of Tegoprazan in Healthy Chinese Subjects

Tegoprazan is one of the potassium-competitive acid blockers (P-CABs). It exhibits its anti-secretory effects by competitively and reversibly blocking the availability of K+ of the H+, K+-ATPase. This study was designed to investigate the safety and pharmacokinetics of tegoprazan in healthy Chinese subjects. Thirty-eight healthy Chinese subjects were recruited in this randomized, single-center, double-blind, placebo-controlled study, with a single ascending dose of 50, 100, 200 mg and a multiple dose of 100 mg for 10 days. The plasma concentration of tegoprazan was determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Pharmacokinetics were evaluated via non-compartmental and compartmental model analysis. Safety was assessed by physical examinations, vital signs, clinical laboratory tests, and electrocardiograms. No serious adverse event was observed in this study. After single-dose administration (50, 100 and 200 mg), tegoprazan was rapidly absorbed with a median maximum measure plasma concentration (Tmax) at 0.5h and declined with a terminal (elimination) half-life (t1/2) of 3.87-4.57h. The maximum measured plasma concentration (Cmax) for tegoprazan was 813.80, 1494.60 and 2829.00 ng/mL. Meanwhile, the correspondingarea under the concentration-time curve (AUC)from time zero to infinity (AUC0-inf)was 2761.00, 5980.05 and 11,044.72 ng∙h/mL in 50, 100, 200 mg group, respectively. Dose-dependent increase was observed in the value of Cmax and AUC after administration of tegoprazan 50 to 200 mg. The two-compartment model well described the pharmacokinetic profile of tegoprazan. In the steady state, no accumulation was found after repeated administration at the 100-mg dose level. No experimental differences were found based on gender. Tegoprazan was well tolerated in the dose range of 50-200 mg in single- and 100 mginmultiple-dose studies. Tegoprazan shows dose linearity with oral administration after a single dose of 50 to 200 mg and less drug accumulation after 10 days of continuous administration in 100 mg.

Dextran sulfate sodium-induced colitis and ginseng intervention altered oral pharmacokinetics of cyclosporine A in rats

Ethnopharmacological relevanceApplication of cyclosporine A (CsA) as a rescue treatment in acute severe ulcerative colitis (UC) is limited by its narrow therapeutic window and great interpatient variability. As a substrate of cytochrome P450 3A enzyme (CYP3A) and P-glycoprotein (P-gp), the oral pharmacokinetics of CsA is susceptible to disease status and concomitant medications. Combined treatment with ginseng, a famous medicinal herb frequently prescribed for ameliorating abnormal immune response in many diseases including UC, showed immunologic safety in CsA-based immunosuppression. Aim of the studySince the therapeutic levels of CsA can be achieved within 24 h, this study first assessed the impact of acute colitis and ginseng intervention on the single oral dose pharmacokinetics of CsA and explored the underlying mechanisms in dextran sulfate sodium (DSS)-induced colitis rats and Caco-2 cells. Materials and methodsRats received drinking water (normal group), 5% DSS (UC group), or 5% DSS plus daily oral ginseng extract (GS+UC group). On day 7, GS+UC group only received an oral dose of CsA (5 mg/kg), while animals of normal or UC group received an oral, intravenous (1.25 mg/kg), or intraperitoneal dose of CsA (1.25 mg/kg), respectively. Blood, liver/intestine tissues and fecal samples were collected for determining CsA and main hydroxylated metabolite HO-CsA or measuring hepatic/intestinal CYP3A activity. Caco-2 cells were incubated with gut microbial culture supernatant (CS) of different groups or ginseng (decoction or polysaccharides), and then CYP3A, P-gp and tight junction (TJ) proteins were determined. ResultsOral CsA exhibited enhanced absorption, systemic exposure and tissue accumulation, and lower fecal excretion, while intravenous or intraperitoneal CsA showed lower systemic exposure and enhanced distribution, in colitis rats. Diminished intestinal and hepatic P-gp expression well explained the changes with DSS-induced colitis. Moreover, blood exposures of HO-CsA in both normal and colitis after oral dosing were significantly higher than intravenous/intraperitoneal dosing, supporting the dominant role of intestinal first-pass metabolism. Interestingly, colitis reduced CYP3A expression in intestine and liver but only potentiated intestinal CYP3A activity, causing higher oral systemic exposure of HO-CsA. Oral ginseng mitigated colitis-induced down-regulation of CYP3A and P-gp expression, facilitated HO-CsA production, biliary excretion and colonic sequestration of CsA, while not affected CsA oral systemic exposure. In Caco-2 cells, gut microbial CS from both colitis and GS+UC group diminished P-gp function, while ginseng polysaccharides directly affected ZO-1 distribution and suppressed TJ proteins expression, explaining unaltered oral CsA systemic exposure. ConclusionsDSS-induced colitis significantly altered oral CsA disposition through regulating intestinal and hepatic P-gp and CYP3A. One-week ginseng treatment enhanced colonic accumulation while not altered the systemic exposure of CsA after single oral dosing, indicating pharmacokinetic compatibility between the two medications.

Pharmacokinetics of ASP4345 from Single Ascending-Dose and Multiple Ascending-Dose Phase I Studies.

BackgroundCognitive impairment is a core feature of schizophrenia. While first- and second-generation antipsychotic drugs treat psychotic exacerbations, no treatment is approved for the cognitive dysfunction. We have identified ASP4345, a positive allosteric modulator of the dopamine type 1 (D1) receptor that selectively binds to, and enhances the activity of, D1 receptors. ASP4345 has the potential to be an effective and well-tolerated treatment option for cognitive impairment associated with schizophrenia.ObjectiveThe objective of this study was to determine the pharmacokinetics of ASP4345 in two phase I single ascending-dose and multiple ascending-dose studies.MethodsBoth phase I studies were randomized, double blind, and placebo controlled. The single dose-ascending study assessed pharmacokinetics of single oral doses of 3–900 mg of ASP4345 or placebo in the fasted state in healthy adult volunteers. This study also assessed cerebrospinal fluid pharmacokinetics, as well as the effects of food on pharmacokinetic parameters. The multiple ascending-dose study (NCT02720263) assessed the pharmacokinetics of multiple oral doses of 3–150 mg of ASP4345 in patients with schizophrenia or schizoaffective disorder receiving stable antipsychotic drug treatment. The pharmacokinetic data from both studies were summarized using descriptive statistics.ResultsThe plasma concentration–time profile in both studies showed a rapid increase in concentrations of ASP4345. The median time to maximum concentration range was 1.00–2.26 h in the single ascending-dose study in the fasted state and 1.25–3.02 h in the multiple ascending-dose study at steady state. There were less than dose-proportional increases in maximum concentration and area under the curve in the single ascending-dose study, where doses had a range from 3 to 900 mg, and in the multiple ascending-dose study in patients with stabilized schizophrenia or schizoaffective disorder, where doses had a range from 3 to 150 mg. The mean terminal elimination half-life was dose independent and had a range from 9.12 to 14.3 h in the single ascending-dose study and from 11.1 to 26.8 h in the multiple ascending-dose study. Additionally, in the single ascending-dose study, absorption of 300 mg of ASP4345 was slightly delayed when administered in the fed state compared with the fasted state; median time to maximum concentration was 1.5 h under the fasting state and 4.0 h under fed states. All other pharmacokinetic parameters were comparable for both conditions. ASP4345 appeared in the cerebrospinal fluid with some delay; time to maximum concentration range was from 2.48 to 7.98 h in cerebrospinal fluid compared with 0.75 to 1.03 h in plasma (median cerebrospinal fluid/plasma = 0.188). The ratio of cerebrospinal fluid to total plasma for area under the curve from 0 to 24 h (0.157–0.573%) and maximum concentration (0.0899–0.311%) and the ratio of cerebrospinal fluid to unbound plasma for maximum concentration (25.0–86.4%) confirm the distribution of ASP4345 into the brain.ConclusionsThe pharmacokinetics of ASP4345 suggest that single daily dosing is appropriate for ASP4345. Furthermore, the concentration of ASP4345 in cerebrospinal fluid compared to free drug concentrations in plasma provides evidence of penetration of ASP4345 into the brain.

A Study to Evaluate the Pharmacokinetics of Single Oral Doses of Ozanimod in Healthy Adult Chinese Subjects

A Study to Evaluate the Pharmacokinetics of Single Oral Doses of Ozanimod in Healthy Adult Chinese Subjects

Effects of hydrochlorothiazide and amlodipine on single oral dose pharmacokinetics of valsartan in healthy Korean subjects: Population model-based approach

Fixed dose combination (FDC) of valsartan (VAL) and hydrochlorothiazide (HCT) or VAL and amlodipine (AML) has been available in many countries for the treatment of hypertension. Due to drug-drug interaction potentials, in the current study we aimed to evaluate potent effects of HCT and AML on pharmacokinetics (PKs) of VAL when they are orally co-administered as FDC (VAL/HCT at 80/12.5 mg or 160/12.5 mg; and VAL/AML at 160/5 mg or 160/10 mg) products in healthy Korean subjects. Population pharmacokinetic (PK) modeling and analysis were performed by the nonlinear mixed-effects modeling software. PKs of VAL was described by two-compartment disposition model, first-order elimination, four-sequential first-order absorption model, correlation between apparent clearances and volumes of distribution, and lag time. For all FDCs, there were no statistically significant differences in both maximum concentration and areas under the concentration-time curves (AUCs) of VAL in comparison to those when administered VAL alone, except the combination of VAL/AML at 160/10 mg, where AUC0–∞ increased by 11.8% in mean and 6.86% in median. In addition, there was an increasing trend in time to reach peak (Tmax) of VAL in FDCs, where it was increased by 0.22–0.34 h in mean and 0.40–0.44 h in median, except the combination of VAL/HCT at 160/12.5 mg. However, these differences in AUC0–∞ and Tmax might not be considered as clinically important. In conclusion, HCT or AML has no potent effect on PKs of VAL when they are co-administered as FDC products. No dose adjustment for VAL is recommended when co-administered with HCT or AML.

Pharmacokinetics of Single Oral Dose Extended-Release Levetiracetam in Healthy Cats.

BackgroundRepeated PO dosing of anti‐epileptic drugs may contribute to poor compliance in treated cats. Intermediate‐release levetiracetam has been used safely in cats, but must be given q8h to maintain serum concentrations in the therapeutic interval for humans (5–45 μg/mL). Approved extended‐release levetiracetam (XRL) for human use may require less frequent dosing, but the large dosing unit has limited its use in cats.HypothesesIn healthy cats, serum levetiracetam concentration will remain above 5 μg/mL for at least 24 hours after administration of a single dose of XRL PO and will be well tolerated.Animals7 healthy cats.MethodsExtended‐release levetiracetam (500 mg) was administered PO. Blood was collected and neurologic examination findings recorded at scheduled times over 30 hours. Serum levetiracetam concentration was quantitated by an immunoassay validated in cats. Data were subjected to noncompartmental analysis. Descriptive statistics were reported.ResultsThe median dosage of 86.2 mg/kg, (range, 80–94.3) achieved a mean maximum concentration (C max) of 89.8 ± 25.8 μg/mL at 4.9 ±1.57 hours. Serum levetiracetam was >5 μg/mL in all cats by 90 minutes. Mean concentrations were 43.7 ± 18.4 and 4.9 ± 3.4 μg/mL at 12 and 24 hours, respectively. The half‐life was 4.1 ± 1.0 hours. The drug was well tolerated.Conclusions and Clinical ImportanceA single 500 mg PO dose of XRL safely maintained serum levetiracetam concentration ≥5 μg/mL in healthy cats for at least 21 hours. Clinical efficacy studies in epileptic cats receiving XRL are indicated; however, monitoring should be implemented for individual cats.

Phase 1 Study to Assess Safety, Tolerability and Pharmacokinetics of Single and Multiple Oral Doses of APX001 and to Investigate the Effect of Food on APX001 Bioavailability

Phase 1 Study to Assess Safety, Tolerability and Pharmacokinetics of Single and Multiple Oral Doses of APX001 and to Investigate the Effect of Food on APX001 Bioavailability

Pharmacokinetics of isochlorgenic acid C in rats by HPLC-MS: Absolute bioavailability and dose proportionality

Ethnopharmacological relevanceIsochlorgenic acid C (IAC), one of the bioactive compounds of Lonicera japonica, exhibited diverse pharmacological effects. However, its pharmacokinetic properties and bioavailability remained unresolved. Aim of the studyTo determine the absolute bioavailability in rats and the dose proportionality on the pharmacokinetics of single oral dose of IAC. Materials and methodsA validated HPLC-MS method was developed for the determination of IAC in rat plasma. Plasma concentration versus time data were generated following oral and intravenous dosing. The pharmacokinetic analysis was performed using DAS 3.0 software analysis. Absolute bioavailability in rats was determined by comparing pharmacokinetic data after administration of single oral (5, 10 and 25mgkg−1) and intravenous (5mgkg−1) doses of IAC. The dose proportionality of AUC(0-∞) and Cmax were analyzed by linear regression. ResultsExperimental data showed that absolute oral bioavailability of IAC in rats across the doses ranged between 14.4% and 16.9%. The regression analysis of AUC(0-∞) and Cmax at the three doses (5, 10 and 25mgkg−1) indicated that the equations were y=35.23x+117.20 (r=0.998) and y=121.03x+255.74 (r=0.995), respectively. ConclusionsA new HPLC-MS method was developed to determine the bioavailability and the dose proportionality of IAC. Bioavailability of IAC in rats was poor and both Cmax and AUC(0-∞) of IAC had a positive correlation with dose. Evaluation of the pharmacokinetics of IAC will be useful in assessing concentration-effect relationships for the potential therapeutic applications of IAC.

Abstract 13716: Pharmacokinetics of Pravastatin in Pediatric Dyslipidemia Patients: Clinical Impact of Genetic Variation on Statin Disposition

Background: In adults, genetic variation of the drug transporter, organic anion transporting polypeptide (OATP1B1) encoded by the gene SLCO1B1, decreases hepatic uptake of statins. This leads to increased circulating statin concentrations in plasma, thereby placing patients at higher risk for adverse events and decreased efficacy. Expression of OATP transporters in mice changes during development, raising the question of whether in humans the genotype-phenotype relationship observed in adults is relevant in the developing child. Methods: Participants (8-21 years) with at least one allelic variant of SLCO1B1 c.521 T>C (521TC; n=8) and wild type controls (521TT; n=5) were enrolled in a single oral dose pharmacokinetics (PK) study. Pravastatin and isomers were quantified by liquid chromatography tandem mass spectrometry. A model-independent PK approach was used to define the peak plasma concentration (Cmax), area under the curve (AUC) during the sample period and AUC to infinity. Results: 521TC subjects had a nearly 3-fold increase in Cmax (177.62 vs. 56.53 ng/ml; p=0.001) and AUC (389.81 vs. 139.57 ng/ml*h; p=0.004) compared to 521TT controls (Fig. 1). Formation of the 3-alpha-iso-pravastatin acid and lactone isomers in the acidic environment of the stomach prior to absorption was variable in both groups. There was a linear relationship between pravastatin acid AUC and the ratio of pravastatin acid to total analyte (pravastatin acid, 3-alpha-iso-pravastatin, and corresponding lactones) AUC amongst genetic variants (R=0.8961) that does not appear to be present in the control. Conclusion: The impact of the SLCO1B1 c.521 gene variant on pravastatin PK in adults was replicated in our pediatric cohort. However, other physicochemical factors appear to contribute to variability in the dose-exposure relationship. This data must be replicated in a larger cohort, and the pharmacodynamic consequences assessed, before implementing OATP1B1 driven dosing guidelines.

Single-dose evaluation of safety, tolerability and pharmacokinetics of newly formulated hydromorphone immediate-release and hydrophilic matrix extended-release tablets in healthy Japanese subjects without co-administration of an opioid antagonist.

This single dose, open-label study investigated the safety, tolerability and pharmacokinetics of single oral doses of newly formulated immediate-release (IR) and hydrophilic matrix extended-release (ER) hydromorphone tablets in healthy Japanese subjects without co-administration of an opioid antagonist under fasting and fed conditions. Plasma and urinary concentrations of hydromorphone and metabolites were measured by liquid-chromatography tandem mass-spectroscopy. Following administration of the ER tablet, plasma concentrations of hydromorphone slowly increased with a median tmax of 5.0 h and the Cmax decreased to 37% of the IR tablet, while the AUC0-inf was comparable with that of the IR tablet when administered at the same dose. The degree of fluctuation in the plasma concentration for the ER tablet was much lower than that of the IR tablet and certain levels of plasma concentrations were maintained after 24 h of ER dosing. The AUC0-inf and Cmax increased with food for both IR and ER tablets. The AUC0-inf of hydromorphone-3-glucoside was one-tenth of that of hydromorphone-3-glucuronide. A single oral administration of the hydromorphone tablets would be well-tolerated in healthy Japanese subjects despite a lack of co-administration of an opioid antagonist and the newly developed ER hydromorphone tablets may have the appropriate PK characteristics for once-daily dosing.

Gender-related pharmacokinetics and bioavailability of a novel anticancer chalcone, cardamonin, in rats determined by liquid chromatography tandem mass spectrometry.

A reversed phase liquid chromatography tandem mass spectrometry method was developed and validated for quantification of cardamonin, a potential anticancer chalcone, in rat serum. Curcumin was used as an internal standard. Following liquid-liquid extraction using n-hexane and ethyl acetate (60:40, v/v), the processed samples were chromatographed on a C18 column using acetonitrile and ammonium acetate buffer (0.01 M, pH 4.5) (85:15, v/v) as mobile phase at a flow rate of 0.6 mL min(-1). Mass spectrometric detection was performed in the negative electrospray ionization mode by multiple reaction monitoring (m/z 269→122 and 367→217 for cardamonin and curcumin, respectively). The method was validated in terms of selectivity, accuracy, precision, sensitivity, reproducibility, dilution integrity and stability. The linearity was established in the range of 1-200 ng mL(-1) (r≥0.999). The recovery of cardamonin from spiked serum was always >90%. The intra- and inter-day precision (%RSD) and accuracy (%bias) were well within the acceptable limits. The method was applied for single oral and intravenous dose pharmacokinetics in male and female Sprague Dawley rats. Following oral dose, cardamonin showed peak serum concentration that occurred at ∼2 h with very low bioavailability in both male (0.6%) and female (4.8%) rats. Cardamonin exhibited a significant gender influence on pharmacokinetics and bioavailability in rats.

Pharmacokinetics of Chloroquine and Metronidazole in Rats

Article history: The single oral dose pharmacokinetics of chloroquine (5mg/kg body weight) and metronidazole (7.5mg/kg body weight) were studied in rats' serum. Chloroquine and metronidazole concentrations were measured using high - performance liquid chromatography (HPLC) method developed earlier in our laboratory. The data were fitted into a WinNonlin standard non-compartmental programme. The Maximum serum concentration Cmax (µg/ml) of chloroquine was 5.70 ± 1.41 while that of metronidazole was 3.13  0.30, Time to peak concentration tmax was 1.00  0.00 (h) and that of metronidazole was 0.83 ± 0.27, Volume of distribution Vd (L) 1.33 ± 0.26 for metronidazole 2.39  0.28; Elimination half-life t1/2 (h) 10.05 ± 3.01 for metronidazole 4.05  0.46. The values were comparable with the works of other authors. Compounds that show very high activity in -vitro may not have in vivo activity, or may be highly toxic using in- vivo models due to undesirable pharmacokinetic properties, and toxicity may result from formation of reactive metabolites. This study assures the quality of the brands of the drugs and encouraged the use of animal model in determining pharmacokinetic properties especially in drug design.

Safety, tolerability, and pharmacokinetics of single oral doses of tofacitinib, a Janus kinase inhibitor, in healthy volunteers.

Tofacitinib is an oral Janus kinase inhibitor. This randomized, double-blind, parallel-group, placebo-controlled study was the first evaluation of tofacitinib in humans. The objectives were to characterize the safety and tolerability, pharmacokinetics (PK), and pharmacodynamics of escalating single tofacitinib doses in healthy subjects. Tofacitinib (0.1, 0.3, 1, 3, 10, 30, 60, and 100 mg) or placebo was administered as oral powder for constitution. For each dose, 7-9 subjects were randomized to tofacitinib and 3-5 subjects to placebo. Ninety-five males and females (age range 19-45) completed the study. Forty-nine treatment-emergent all-causality adverse events (AEs) were observed; nausea and headache were the most frequently reported. Tofacitinib PK was characterized by rapid absorption (time to peak serum concentration [Tmax ] 0.5-1 hour), rapid elimination (mean terminal half-lives 2.3-3.1 hours), and dose-proportional systemic exposures (peak serum concentration [Cmax ] and area under the serum concentration-time curve from time zero to infinity [AUC0-∞ ]). No appreciable correlation was observed between tofacitinib dose and lymphocyte subset counts. Single-dose tofacitinib up to 100 mg in healthy subjects had a safety profile of mostly mild AEs, and no deaths, serious AEs, severe AEs or discontinuations due to AEs.

Single- and multiple dose pharmacokinetics and multiple dose pharmacodynamics of oral ABT-116 (a TRPV1 antagonist) in dogs.

Six dogs were used to determine single and multiple oral dose pharmacokinetics of ABT-116. Blood was collected for subsequent analysis prior to and at 15, 30 min and 1, 2, 4, 6, 12, 18, and 24 h after administration of a single 30 mg/kg dose of ABT-116. Results showed a half-life of 6.9 h, k(el) of 0.1/h, AUC of 56.5 μg·h/mL, T(max) of 3.7 h, and C(max) of 3.8 μg/mL. Based on data from this initial phase, a dose of 10 mg/kg of ABT-116 (no placebo control) was selected and administered to the same six dogs once daily for five consecutive days. Behavioral observations, heart rate, respiratory rate, temperature, thermal and mechanical (proximal and distal limb) nociceptive thresholds, and blood collection were performed prior to and 4, 8, and 16 h after drug administration each day. The majority of plasma concentrations were above the efficacious concentration (0.23 μg/mL previously determined for rodents) for analgesia during the 24-h sampling period. Thermal and distal limb mechanical thresholds were increased at 4 and 8 h, and at 4, 8, and 16 h respectively, postdosing. Body temperature increased on the first day of dosing. Results suggest adequate exposure and antinociceptive effects of 10 mg/kg ABT-116 following oral delivery in dogs.

Abstract 3255: Single oral dose pharmacokinetics of cancer chemopreventive phytochemicals from Angelica gigas Nakai in men and women

Abstract The ethanol extracts of the root of Korean herb Angelica gigas Nakai (AGN) have promising anti-cancer, anti-nociceptive and other activities in rodent models. It is currently believed that the pyranocoumarin decursin and its structural isomer decursinol angelate (DA) in such extracts contribute to the in vitro anti-cancer activity. We and others have demonstrated that both decursin and DA were extensively converted to decursinol (DOH) in rodents. However, our in vitro experiments using human and rodent S9 fractions suggested the hypothesis that decursin and/or DA might be metabolized differently in humans. Given the notable difference in the biological activities between decursin/DA and DOH, we conducted a single oral dose pharmacokinetic study of these phytochemicals in healthy volunteers to address a key question for human translatability of preclinical animal studies of decursin, DA or AGN extract. Knowing that chemicals other than decursin and DA in AGN had minimal effect on their absorption and metabolism in rodents, we used an AGN-based dietary supplement as the study drug in compliance with the FDA and institutional requirements. In all, 20 healthy subjects (10 men and 10 women) had completed the study in full. AGN product was very well tolerated by all subjects as evidenced by plasma biochemistry, complete blood cell count and physical examination. Analyzing plasma samples using UHPLC-MS/MS showed that, though humans metabolized DA slightly slower than rodents, both decursin and DA were extensively converted to DOH. Gender and racial/ethnicity do not appear to dramatically affect the PK parameters. Since we show here that humans metabolize decursin and DA in similar pattern with rodents, the anti-cancer efficacy, safety, tissue distribution and pharmacodynamic biomarker data generated in rodent models will likely be relevant for human translation. In spite of the limited number of healthy individuals in the trial, this project demonstrated feasibility for our team to consider translational research in disease-oriented populations. Citation Format: Jinhui Zhang, Li Li, Thomas W. Hale, Wayne Chee, Chengguo Xing, Cheng Jiang, Junxuan Lü. Single oral dose pharmacokinetics of cancer chemopreventive phytochemicals from Angelica gigas Nakai in men and women. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3255. doi:10.1158/1538-7445.AM2014-3255

Lurasidone drug-drug interaction studies: a comprehensive review.

To evaluate potential drug-drug interactions with the atypical antipsychotic lurasidone. Seven phase I studies were conducted to investigate the effects of repeated dosing of ketoconazole, diltiazem, rifampin, or lithium on the pharmacokinetics (PK) of single oral doses of lurasidone, or the effects of repeated dosing of lurasidone on the PK of digoxin, midazolam, or the oral contraceptive norgestimate/ethinyl estradiol. Two 6-week, phase III studies included evaluation of the potential for interaction between lurasidone and lithium or valproate. Maximum serum or plasma concentration (Cmax) and area under the concentration-time curve (AUC) were calculated. Concomitant ketoconazole administration resulted in a 6.8-fold increase in lurasidone Cmax and a 9.3-fold increase in lurasidone AUC; concomitant diltiazem administration resulted in 2.1- and 2.2-fold increases, respectively. Rifampin decreased lurasidone Cmax and AUC (one-seventh and one-fifth of lurasidone alone, respectively). Steady-state dosing with lurasidone increased Cmax and AUC0-24 (AUC from time 0 to 24 h postdose) of digoxin by 9% and 13%, respectively, and of midazolam by 21% and 44%, respectively. There were no significant interactions between lurasidone and lithium, valproate, ethinyl estradiol, or norelgestromin (the major active metabolite of norgestimate). Lurasidone PK is altered by strong cytochrome P450 (CYP) 3A4 inhibitors or inducers, and coadministration is contraindicated; whereas moderate CYP3A4 inhibitors have less effect, and lurasidone dosage restrictions are recommended. No dose adjustment for lurasidone is needed when administered with lithium or valproate. Dose adjustment is not required for lithium, valproate, digoxin (a P-glycoprotein substrate), or midazolam or oral contraceptives (CYP3A4 substrates) when coadministered with lurasidone.

Phase 1 Clinical Trial Of The Candidate Anti-Sickling Agent Aes-103 In Adults With Sickle Cell Anemia

BackgroundAes-103 (5-hydroxymethylfurfural, 5-HMF) is a putative anti-sickling agent that has undergone pre-clinical testing for potential treatment for sickle cell disease. It is an organic compound derived from dehydration of certain sugars, found commonly in small amounts in foods such as coffee and prunes. It binds to alpha subunits of hemoglobin and increases its oxygen affinity. At millimolar levels, it inhibits hypoxia-induced sickling in vitro and protects sickle cell mice against hypoxia-induced death. We investigated the safety, tolerability and pharmacokinetics of single oral doses of Aes-103 in a double-blind, placebo controlled, dose-escalation trial in adult patients with sickle cell anemia on hydroxyurea treatment and not on hydroxyurea treatment. MethodsAdult patients with sickle cell anemia consented to an IRB-approved FDA investigational New Drug protocol at the NIH Clinical Center. After laboratory evaluation to screen for acceptable clinical status, they were hospitalized for three nights to receive oral dosing of Aes-103 or placebo (5:1 ratio of treatments) in a double-blind design, and vital signs, toxicity monitoring lab results and any adverse events were reviewed by a protocol safety committee, which approved escalation to the next higher dose of study drug. The patients were eligible to be hospitalized again at least one week later for a second, higher dose or placebo. After fasting, patients received oral doses of Aes-103 dissolved in orange juice. Doses were 300, 1000, 2000 or 4000 mg. A subgroup that took 4000 mg after fasting also took 4000 mg after a prescribed high fat meal during a second hospitalization and 1000 mg every 6 hours for four doses without fasting during a third hospitalization. ResultsEighteen patients in steady state participated in the trial. The study drug was well tolerated at all doses tested. During the first 24 hours after dosing, a total of 11 adverse events (9 mild, 2 moderate, and zero severe) occurred distributed across a variety of categories in 6 of 15 patients on the Aes-103 arm, compared to 1 mild adverse event in 1 of 3 patients on the placebo arm. An additional 18 adverse events were temporally unrelated to Aes-103, 10 of which involved pain that appeared to be background sickle cell-related pain unrelated to dosing of study drug, seen also in 1 of the 3 placebo adverse events. No severe adverse events occurred in temporal relationship to the study drug. Pharmacokinetic and pharmacodynamic data are currently under analysis, and will be complete at the time of abstract presentation. ConclusionsAes-103 was safely tolerated without severe or recurrently observed complications over a 13-fold range of oral doses. A phase 2 randomized controlled study of Aes-103 or placebo is planned with daily dosing for twenty-eight days in patients with sickle cell anemia. Disclosures:Stern:AesRx, LLC: Equity Ownership.