Plasma Pharmacokinetic Parameters Research Articles

CKD-516 potentiates the anti-cancer activity of docetaxel against epidermal growth factor receptor tyrosine kinase inhibitor-resistant lung cancer.

Lung cancer is the leading cause of cancer death. Although docetaxel has been used as a second- or third-line treatment for non-small cell lung cancer (NSCLC), the objective response rate is less than 10%. Hence, there is a need to improve the clinical efficacy of docetaxel monotherapy; combination therapy should be considered. Here, we show that CKD-516, a vascular disruption agent, can be combined with docetaxel to treat epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI)-resistant NSCLC. CKD-516 was orally bioavailable; neither CKD-516 nor docetaxel affected the mean plasma concentration-time profile or pharmacokinetic parameters of the other drug. CKD-516 and docetaxel synergistically inhibited the growth of H1975 (with an L858R/T790M double mutation of EGFR) and A549 (with a KRAS mutation) lung cancer cell lines. In addition, docetaxel plus CKD-516 delayed tumor growth in-and extended the lifespan of-tumor-bearing mice. Thus, combination CKD-516 and docetaxel therapy could be used to treat EGFR-TKI-resistant NSCLC.

Impact of feminizing hormone therapy on tenofovir and emtricitabine plasma pharmacokinetics: a nested drug-drug interaction study in a cohort of Brazilian transgender women using HIV pre-exposure prophylaxis.

ObjectivesPotential interactions between feminizing hormone therapy (FHT) and pre-exposure prophylaxis (PrEP) may be a barrier to PrEP use among transgender women (TGW). We aimed to assess the impact of FHT on PrEP plasma pharmacokinetics (PK) among TGW.MethodsThis was a PK substudy of the effects of FHT on tenofovir disoproxil fumarate/emtricitabine nested to a trans-specific PrEP demonstration study (NCT03220152). Participants were assigned to receive PrEP only (noFHT) or standardized FHT (sFHT; oestradiol valerate 2–6 mg plus spironolactone 100–300 mg) plus PrEP for 12 weeks, after which they could start any FHT (aFHT). Short- and long-term PK assessment occurred at Weeks 12 and 30–48, respectively (plasma samples prior and 0.5, 1, 2, 4, 6, 8 and 24 h after dose). Non-compartmental PK parameters of tenofovir and emtricitabine were compared as geometric mean ratios (GMRs) between noFHT and PrEP and FHT (sFHT at short-term PK; aFHT at long-term PK) participants.ResultsNo differences in tenofovir and emtricitabine plasma PK parameters were observed between the short-term PK of noFHT (n = 12) and sFHT participants (n = 18), except for emtricitabine Cmax [GMR: 1.15 (95% CI: 1.01–1.32)], or between noFHT short-term PK and aFHT long-term PK (n = 13). Most participants were on oestradiol valerate 2 mg at the short-term PK (56%) and 4 mg at the long-term PK (54%). Median (IQR) oestradiol levels were 56.8 (43.2–65.4) pg/mL at short-term PK (sFHT) and 44.8 (24.70–57.30) pg/mL at long-term PK (aFHT). No participants in this analysis seroconverted during the study.ConclusionsOur results indicate no interaction of FHT on tenofovir levels, further supporting PrEP use among TGW using FHT.

Abstract CT242: KRYSTAL-16: A phase I/Ib trial of adagrasib (MRTX849) in combination with palbociclib in patients with advanced solid tumors with KRASG12C mutation

Abstract Background: KRAS is a key mediator of the RAS/MAPK signaling cascade and promotes cellular growth and proliferation. It is the most frequently mutated oncogene in cancer, and KRASG12C mutations occur in 3-4% of colorectal cancers (CRC) and in up to 14% of non-small-cell lung cancers (NSCLC). The investigational agent adagrasib, a potent, covalent inhibitor of KRASG12C, irreversibly and selectively binds to KRASG12C and locks it in its inactive state. Adagrasib was optimized for favorable pharmacokinetic (PK) properties, including long half-life (~24 h), dose-dependent PK, and central nervous system penetration. Initial results have shown encouraging antitumor activity and tolerability of adagrasib monotherapy or combination therapy in patients with CRC or NSCLC harboring KRASG12C mutations. Cyclin D1 and cyclin-dependent kinases (CDK) 4 and 6 are downstream of signaling pathways that lead to cellular proliferation. Palbociclib, a CDK4/6 inhibitor, disrupts cancer cell proliferation by inducing cell cycle arrest by preventing the G1 to S phase transition. Preclinical data in KRASG12C mouse models suggest enhanced antitumor activity when combining adagrasib and palbociclib compared with either agent as a monotherapy. Trial Design: KRYSTAL-16 (NCT05178888) is a multicenter phase I/Ib trial evaluating the safety, PK, pharmacodynamics, and preliminary clinical activity of adagrasib in combination with palbociclib in patients with solid tumors harboring a KRASG12C mutation previously treated with at least 1 standard therapy. The first stage of the trial will comprise a PK lead-in to evaluate potential drug-drug interactions. Exploration of the dose and regimen will continue for the combination of adagrasib (starting dose 400 mg BID) and palbociclib, with expansion cohorts implemented as applicable to further evaluate the safety and preliminary clinical activity of the combination. Decisions regarding dose escalation, expansion, or de-escalation will be determined using the modified Toxicity Probability Interval (mTPI-2) design. Study endpoints include safety, maximum tolerated dose (MTD) and/or recommended Phase II combination dose regimen (RP2D), plasma PK parameters, and preliminary clinical activity (objective response rate [RECIST v1.1], duration of response, progression-free survival, and overall survival). Patients will receive treatment until disease progression, unacceptable adverse events, patient withdrawal, or death. This study will be enrolling at sites in the United States. Citation Format: David Sommerhalder, Jeena Thevathasan, Xenophon Ianopulos, Weining Volinn, David Hong. KRYSTAL-16: A phase I/Ib trial of adagrasib (MRTX849) in combination with palbociclib in patients with advanced solid tumors with KRASG12C mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT242.

Gender Differences in Levodopa Pharmacokinetics in Levodopa-Naïve Patients With Parkinson's Disease.

BackgroundLevodopa (LD) is the most effective drug in the treatment of Parkinson’s disease (PD). Unfortunately, prolonged use of LD leads to complications, mainly motor/non-motor fluctuations (MNMF) and dyskinesias (DYS). Women seem more prone to develop such LD-related complications. Nonetheless, there is a paucity of prospective studies examining gender-related predictors of MNMF and DYS. Among several factors, which concur with a very complex scenario, changes in LD pharmacokinetics influence the drug’s effectiveness. The present study aimed to assess gender-related differences in LD pharmacokinetics in patients with PD at their first-ever intake of LD.Materials and MethodsThis is a multicentric study enrolling patients with PD, who were LD-naïve and received a single dose of LD/benserazide (100/25 mg) formulation. All participants gave their written informed consent, and the study was approved by the local Ethics Committees. To measure plasma LD concentrations and pharmacokinetic parameters (AUC, Cmax, Tmax, t1/2), fasting blood samples were collected before drug intake and then at 8-time points until 260 min. LD concentrations were measured by ultra-high-performance liquid chromatography coupled with mass spectrometry (UHPLC-MS). Multiple linear regression analyses were performed to identify the predictors of the parameters.ResultsThirty-five patients (16 women and 19 men) were consecutively enrolled. Area under curve (AUC) and maximum plasma concentration (Cmax) were significantly higher in women than men (p = 0.0006 and p = 0.0014, respectively). No statistically significant difference was found regarding Tmax and t1/2. Multiple linear regression analyses revealed that female sex (β = 1.559116, 95% CI 0.8314479 2.286785; p < 0.0001) and body mass index (BMI) (β = −0.0970631, 95% CI −0.1733004 −0.0208258; p = 0.014) significantly predicted AUC. Only female sex significantly predicted Cmax (β = 1,582.499, 95% CI 731.581 2,433.417; p = 0.001). Moreover, only BMI significantly predicted t1/2 (β = 0.0756267, 95% CI 0.0143407 0.1369126; p = 0.017). Stratifying by gender, BMI was confirmed to significantly predict t1/2 in women (β = 0.1300486, 95% CI 0.0172322 0.242865; p = 0.027), but not in men.ConclusionThis study provides novel insights on gender differences in LD pharmacokinetics, possibly contributing to the later development of motor complications and dyskinesia in PD.

Pharmacokinetics, Prostate Distribution and Metabolic Characteristics of Four Representative Flavones after Oral Administration of the Aerial Part of Glycyrrhiza uralensis in Rats.

(1) Background: The aerial part of G. uralensis had pharmacological effects against chronic non-bacterial prostatitis (CNP), and flavonoids are the main efficacy components. The purpose of this study was to obtain the pharmacokinetics, prostate distribution and metabolic characteristics of some flavonoids in rats. (2) Methods: The prototype flavones and the metabolites of four representative flavonoids, namely puerarin, luteolin, kaempferol and pinocembrin in plasma, prostate, urine and feces of rats were analyzed by UPLC-Q-Exactive Orbitrap-MS. In addition, the pharmacokinetic parameters in plasma and distribution of prostate of four components were analyzed by HPLC-MS/MS. (3) Results: In total, 22, 17, 22 and 11 prototype flavones were detected in the prostate, plasma, urine and feces, respectively. The metabolites of puerarin in the prostate are hydrolysis and glucose-conjugated products, the metabolites of kaempferol and luteolin in the prostate are methylation and glucuronidation, and the metabolites of pinocembrin in the prostate are naringenin, oxidation, sulfation, methylation and glucuronidation products. The t1/2 of puerarin, luteolin, kaempferol and pinocembrin was 6.43 ± 0.20, 31.08 ± 1.17, 18.98 ± 1.46 and 13.18 ± 0.72 h, respectively. The concentrations of the four flavonoids in prostate were ranked as kaempferol > pinocembrin > luteolin > puerarin. (4) Conclusions: Methylation and glucuronidation metabolites were the main metabolites detected in the prostate. A sensitive and validated HPLC–MS/MS method for simultaneous determination of puerarin, luteolin, kaempferol and pinocembrin in rat plasma and prostate was described, and it was successfully applied to the pharmacokinetic and prostate distribution studies.

Tissue Distribution, Excretion, and Interaction With Human Serum Albumin of Total Bioflavonoid Extract From Selaginella doederleinii

Selaginella doederleinii Hieron is a traditional Chinese medicinal herb widely used to treat different cancers. Previously, we showed that the total bioflavonoid extract of S. doederleinii (TBESD) exhibits anti-carcinogenic activities both in vitro and in vivo. However, the plasma protein binding and pharmacokinetics parameters of TBESD remain unclear. To investigate plasma protein binding, tissue distribution, and excretion of TBESD, rats were administered a single dose of TBESD (600mg/kg) intragastrically and tissue distribution and excretion of TBESD components were determined by rapid high-performance liquid chromatography and tandem mass spectrometry. TBESD binding to human serum albumin (HSA) was assessed by fluorescence spectroscopy. TBESD components amentoflavone, delicaflavone, robustaflavone, 2″,3″-dihydro-3',3‴-biapigenin, and 3',3‴-binaringenin were rapidly absorbed and distributed in various tissues, mostly in the lungs, kidneys, and ovaries, without long-term accumulation. The excretion of bioflavonoids occurred mostly via the intestinal tract and constituted 30% of the administered dose up to 48h. Spectral analysis indicated that TBESD had a dynamic quenching effect on HSA by binding to one HSA site through hydrophobic interactions and hydrogen bond formation. This is the first comprehensive report on the tissue distribution, excretion, and plasma protein binding of TBESD. This study provides important information on TBESD pharmacokinetics necessary for its further development into a therapeutic form for clinical applications.

The effect of ketoprofen on the plasma concentration and pharmacokinetic parameters of ciprofloxacin in chickens

Ciprofloxacin (CFX) and ketoprofen (KPN) are used widely in combination in veterinary interventions for bacterial infections, so in this study the effect of KPN was studied on the efficacy of CFX, by measuring its plasma concentration and pharmacokinetic parameters in 7-10 day-old chickens. The analgesic median effective dose (ED50) of KPN was determined to be 1.62 mg/kg, IM, in the chickens. The preferable analgesic dose of KPN to be used with CFX was 4 mg/kg, IM, which differs significantly from KPN 2 mg/kg, IM,. The CFX plasma concentrations alone (8 mg/kg, IM) measured at different times (0.5, 1, 2, 4 and 24 hours) were 3.31, 3.60, 3.21, 2.70 and 0.17 μg/mL while its concentration was elevated by 53, 54, 90, 107 and 418 % when coadministered with KPN (4 mg/kg, IM) to 5.05, 5.53, 6.10, 5.59 and 0.88 μg/mL in the chickens, respectively. CFX pharmacokinetic parameters, such as the area under the curve (AUC), the area under the moment curve (AUMC), mean residence time (MRT), half-life (t1/2β), Tmax, and Cmax increased when KPN was coadministered with CFX by 129, 289, 70, 49, 100 and 69 %, whereas the elimination rate constant (Kel), the volume of distribution at steady state (Vss) and clearance (Cl) decreased by 36, 34 and 58 %, respectively. It was concluded that coadministration of KPN alters the plasma concentration and the pharmacokinetic parameters of CFX, suggesting that the CFX dose can be reduced when used with KPN to achieve the desired concentration of CFX in the plasma, as an antibacterial for treatment of infected animals.

Effects of Hepatic Impairment on the Pharmacokinetic Profile and Safety of Lobeglitazone.

In this open-label, single-dose, parallel-group study, we compared the pharmacokinetic profile and safety of lobeglitazone, a thiazolidinedione acting as an agonist for peroxisome proliferator-activated receptors, in patients with hepatic impairment (HI) and healthy matched controls for age, sex, and body weight. After a single oral dose of lobeglitazone (0.5 mg), the lobeglitazone (parent drug) and M7 (major metabolite) plasma concentrations and pharmacokinetic parameters were analyzed and compared between the HI patient groups and healthy matched control groups. The geometric mean ratio (GMR; 90% confidence interval [CI]) for maximum concentration (Cmax ) and area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUCinf ) of lobeglitazone was 1.06 (0.90-1.24) and 1.07 (0.82-1.40), respectively, for mild HI vs control A. The GMR (90%CI) of Cmax and AUCinf was 0.70 (0.56-0.88) and 1.00 (0.72-1.37), respectively, for moderate HI vs control B. For M7, the GMR (90%CI) of Cmax and AUCinf was 1.09 (0.75-1.57) and 1.18 (0.71-1.97), respectively, for mild HI vs control A and 1.50 (0.95-2.38) and 1.79 (1.06-3.04), respectively, for moderate HI vs control B. Notable adverse events or tolerability issues were not observed. Lobeglitazone may be safely used in patients with mild or moderate HI without dose adjustment.

Omadacycline pharmacokinetics and soft-tissue penetration in diabetic patients with wound infections and healthy volunteers using in vivo microdialysis.

ObjectivesWe assessed the plasma and soft-tissue pharmacokinetic exposure of omadacycline in infected patients with diabetic foot infection (DFI) and healthy volunteers using in vivo microdialysis.MethodsEight patients and six healthy volunteers were enrolled and received an omadacycline IV loading dose (200 mg) followed by two oral doses (300 mg) every 24 h. Microdialysis catheters were placed in the soft tissue near the infected diabetic foot wound (patients) or thigh (healthy volunteers). Plasma and dialysate fluid samples were collected, starting immediately prior to the third dose and continued for 24 h post-dose. Protein binding was determined by ultracentrifugation.ResultsThe mean ± SD omadacycline pharmacokinetic parameters in plasma for infected patients and healthy volunteers were: Cmax, 0.57 ± 0.15 and 1.14 ± 0.26 mg/L; t½, 16.19 ± 5.06 and 25.34 ± 12.92 h; and total omadacycline AUC0–24, 6.27 ± 1.38 and 14.06 ± 3.40 mg·h/L, respectively. The omadacycline mean plasma free fraction was 0.21 and 0.20 for patients and healthy volunteers, corresponding to free plasma AUC0–24 of 1.13 ± 0.37 and 2.78 ± 0.55 mg·h/L, respectively. Omadacycline tissue AUC0–24 was 0.82 ± 0.38 and 1.37 ± 0.48 mg·h/L for patients and volunteers, respectively.ConclusionsThe present study describes the plasma and soft-tissue exposure of omadacycline in patients with DFI and healthy volunteers. Integrating these data with the microbiological, pharmacokinetic/pharmacodynamic and clinical efficacy data is foundational to support clinical assessments of omadacycline efficacy specifically for DFI. This, coupled with the once-daily oral administration, suggests omadacycline could be an advantageous translational therapy for the hospital and outpatient setting.

P06 Pharmacokinetics and renal accumulation of VRP-034

BackgroundNephrotoxicity is a dose-limiting factor for polymyxin B (PMB), a last-line therapy for MDR Gram-negative bacterial infections. The majority of the filtered PMB undergoes extensive tubular reabsorption leading to significant accumulation of the drug in tubular cells, causing renal tubular damage. We have previously reported that VRP-034, a novel PMB formulation, attenuates this damage (Roy et al.1). The objective of this study was to characterize the pharmacokinetics (PK) and renal accumulation of VRP-034 versus marketed PMB.Materials and methodsA total of 19 Sprague-Dawley rats were used in the study. For PK evaluation, 10 rats were administered a single subcutaneous dose (6 mg/kg) of either VRP-034 or marketed PMB. Serial plasma samples were collected up to 24 h and assayed for major PMB components (PMB B1, B1-I, B2) using a validated LC-tandem MS method. PK parameters were calculated using noncompartmental analysis. For evaluating renal deposition, nine rats (n = 3 each group) were administered VRP-034 or marketed PMB at a dose of 6 mg/kg/8 h for 48 h or normal saline (control). After 48 h, rats were euthanized and kidneys were excised by making a midline incision, washed with saline, homogenized in 1:9 w/v 0.1 M phosphate buffer (pH 7.4) and the homogenate was used for determining PMB concentration. All values are expressed as mean ± SEM.ResultsThe plasma pharmacokinetic parameters for both VRP-034 and marketed PMB were found similar [AUC0–24: 54.3 ± 4.7 μg/mL·h versus 51.5 ± 1.6 μg/mL·h; Cmax: 4.73 ± 0.6 μg/mL versus 5.02 ± 0.5 μg/mL; T½: 5.95 ± 0.5 h versus 5.6 ± 0.3 h]. In the renal deposition study, a 40% reduction (P<0.05) in renal deposition of PMB was found in VRP-034 treated rat kidneys compared with marketed PMB group after 48 h of treatment.ConclusionsThe results highlight that while the plasma PK parameters remained unchanged, a marked reduction in PMB renal deposition was observed in VRP-034 group and likely explains the previous reports of attenuated PMB-induced kidney injury with VRP-034.

Effect of food on capsule and granule formulations of selumetinib.

Selumetinib is an oral, potent, and highly selective allosteric MEK1/2 inhibitor approved for the treatment of pediatric patients (aged ≥2 years) with neurofibromatosis type 1 who have symptomatic, inoperable plexiform neurofibromas. A granule formulation of selumetinib is under development to improve dosing precision for younger pediatric patients who may be unable to swallow capsules. This phase I crossover study investigated the effect of food on the pharmacokinetic (PK) properties of selumetinib capsule and granule formulations. Healthy male volunteers were randomized to receive selumetinib granules (25 mg) or capsules (50 mg [2 × 25 mg]) under fasted or fed conditions (a low‐fat meal). Plasma concentrations and PK parameters were determined less than or equal to 48 h postdose. Safety and tolerability were assessed. Across 24 volunteers, selumetinib was absorbed quickly, with a time to maximum concentration (Tmax) ranging from ~1–3 h. Geometric mean ratios (90% confidence interval [CI]) for maximum plasma concentration (Cmax) in the fed versus fasted state were 0.61 (90% CI 0.51–0.72) and 0.40 (90% CI 0.33–0.48) for the granule and capsule formulations, respectively, whereas geometric mean ratios (90% CI) for area under the plasma drug concentration‐time curve in the fed versus fasted state were 0.97 (90% CI 0.91–1.02) and 0.62 (90% CI 0.55–0.70), respectively. Levels of less than 10% conversion to the N‐desmethyl selumetinib metabolite were observed. Selumetinib was well‐tolerated, with only a few adverse events of mild intensity reported. Selumetinib administration with a low‐fat meal resulted in lower Cmax and longer Tmax for both formulations versus fasted conditions. However, area under the curve for selumetinib granules was similar under fasted and fed conditions. Overall, these findings support further development of this formulation for pediatric patients.

Pharmacokinetics of HupA-PLGA-NPs of different sizes in the mouse blood and brain determined by LC-MS/MS.

Huperzine A, which was extracted from a Chinese herb, is a reversible and selective inhibitor of acetylcholinesterase (AChE), which is used as an anti-Alzheimer's drug that exerts evident pretreatment effects against exposure to organophosphate chemical warfare agents or pesticides. The aims of this study were to establish an LC-MS/MS method for the detection of HupA in biological samples and to investigate the pharmacokinetics of HupA polylactic-co-glycolic acid nanoparticles (HupA-PLGA-NPs) with different diameters in mice. The proposed LC-MS/MS method was established by optimizing the MS conditions and validating the specificity, linear range, lower limit, precision, accuracy, matrix effects, absolute recovery, and sample stability of the method. ICR mice were divided into three treatment groups: the HupA control group, the 46.4-nm HupA-PLGA-NP group and the 208.5-nm HupA-PLGA-NP group. All the mice in the three groups were administered 0.5 mg/kg HupA via the tail vein. The pharmacokinetic parameters in plasma and the brain were detected by LC-MS/MS. Pharmacokinetic parameters were analyzed using PKS pharmacokinetic software, and the relative bioavailability and brain-targeted drug targeting efficiency (DTE) were also calculated. The distributions of HupA-PLGA-NP groups showed marked changes compared with that of HupA in mice in vivo, and the particle size of nanodrugs exerted a significant effect on the pharmacokinetic parameters in mice. The half-life (T1/2) values in plasma of the 46.4- and 208.5-nm HupA-PLGA-NPs were 1.53- and 1.96-fold longer than that of the HupA at the same dose. The bioavailabilities of the two nanoparticles were 1.93- and 2.19-fold higher than that of HupA, respectively. In the brain, the Tmax values of the two HupA-PLGA-NPs of different sizes was 1.25 h, which was clearly longer than that of HupA (0.5 h), and the corresponding T1/2 values were 12.53 h and 8.47 h, which were 1.82- and 1.23-fold higher than that of HupA (6.89 h). In addition, the brain targeting index of the 46.40-nm HupA-PLGA-NPs was 1.48, which revealed an evident brain-targeting effect. The LC-MS/MS method has the advantages of good specificity, high sensitivity and needing a low sample amount and is economical and particularly suitable for determining the drug content in plasma and brain samples. The NP size is associated with the distribution patterns of nanodrugs. Therefore, a particular NP size can be selected to maximize the pharmacodynamics effects and control the toxicity of nanodrugs.

Pharmacokinetics and pharmacodynamics studies of a loading dose of cisatracurium in critically ill patients with respiratory failure

BackgroundPrevious studies reported a slow neuromuscular response with the currently recommended dose of cisatracurium in critically ill patients. Pharmacokinetic and pharmacodynamic studies of cisatracurium in critically ill patients are still limited. To our knowledge, this is the first study performed to better understand the pharmacokinetics (PKs) and pharmacodynamics (PDs) of a loading dose of cisatracurium and to identify factors that affect PK and PD changes in critically ill patients.MethodsA prospective PKs and PDs study was designed. Arterial blood samples of 10 critically ill patients with respiratory failure were collected after administering a loading dose of 0.2 mg/kg of cisatracurium. Plasma cisatracurium and laudanosine concentrations were determined using liquid chromatography-tandem mass spectrometry. The achievement of the desired pharmacodynamic response was evaluated by both 1) clinical assessment and 2) train-of-four monitoring. The PK/PD indices were analyzed for their correlation with patient’characteristics and other factors.ResultsThe one-compartment model best described the plasma pharmacokinetic parameters of cisatracurium. The volume of distribution at steady state and total clearance were 0.11 ± 0.04 L/kg and 2.74 ± 0.87 ml/minute/kg, respectively. The mean time to train-of-four 0/4 was 6 ± 3.86 minutes. A time to the desired pharmacodynamic response of less than 5 minutes was found in 10% of the patients. A positive correlation was found between cisatracurium concentration and albumin levels and between pharmacokinetics data and patient factors [partial pressure of carbon dioxide and respiratory alkalosis].ConclusionThe currently recommended loading dose of cisatracurium might not lead to the desired pharmacodynamic response in critically ill patients with respiratory failure.Trial registrationClinicalTrials.gov, NCT03337373. Registered on 9 November 2017

Prediction of CYP-mediated silybin A-losartan pharmacokineticinteractions using physiological based pharmacokinetic modeling.

The concomitant use of herbal products and synthetic drugs necessitates the assessment of their interaction potentials. The herbal hepatoprotective medicine, silybin A inhibits cytochrome P450 (CYP) 2C9 and 3A4 enzymes, thus, may interact with the drugs that are substrates of CYP2C9 and 3A4, such as losartan. The three most prominent genotypes, expressed by CYP2C9 are the CYP2C9*1/*1, CYP2C9*1/*2 and CYP2C9*1/*3. This study aimed to assess silybin A-losartan interaction in different CYP2C9 genotypes using physiological-based pharmacokinetic (PBPK) model approach. The individual PBPK models for silybin A and losartan were developed using PK-Sim®. Losartan pharmacokinetics was predicted with or without co-administration of silybin A in individuals of different CYP2C9 genotypes to find herbal-drug interaction. The predicted drug plasma curves and pharmacokinetic parameters were optimized using parameter identification tool and were compared with reported pharmacokinetic parameters from the published clinical studies for model validation. The silybin-losartan interactions were predicted by change in area under the curve (AUC) and peak systemic concentration (Cmax). The co-treatment of silybin A, 420mg/24h (140mg/8h) with losartan 50mg/24h, exhibited a genotype-dependent change in the losartan's AUC and Cmax. In CYP 2C9*1/*1 genotype, AUC and Cmax of losartan were increased 1.16 and 1.37 folds, respectively falling in a range stipulated for negligible interaction. Increase in AUC and Cmax by 0.873 and 0.294 folds, respectively in CYP2C9*1/*3 after co-administration of silybin A exhibited a minor interaction with losartan. However, in individuals with CYP2C9*1/*2 genotype, the losartan's AUC and Cmax were decreased by 0.01 folds, manifesting a moderate interaction. Hence, in CYP2C9*1/*1 and CYP2C9*1/*3 genotypes, silybin A is a weak CYP inhibitor for losartan while in CYP2C9*1/*2 genotype, the co-administration of silybin consequents into a moderate pharmacokinetic interaction with losartan.

Pharmacokinetics and tissue distribution of tenofovir, emtricitabine and dolutegravir in mice.

Studies of antiretroviral drug (ARV) tissue distribution in preclinical models, such as mice, are key to understanding viral persistence. To determine the plasma and tissue pharmacokinetics and tissue distributions of tenofovir, emtricitabine and dolutegravir in mice. ARVs were simultaneously administered to two different strains, and their levels in plasma and tissue samples were determined by a validated LC-MS/MS method. A non-compartmental analysis was performed to estimate the main pharmacokinetic parameters. A tissue penetration factor (TPF) was calculated as the ratio of the concentration in the tissue concerned to that in plasma. ARV plasma pharmacokinetic parameters in both strains were similar to those estimated in the clinical context. Tissue concentrations were highest in the digestive tract, followed by the liver and kidneys, lymphatic system, pancreas, adipose tissue and lungs. Tissue concentrations were lowest in the brain. Triple therapy could not be considered effective in any of the tissues considered. The TPF values obtained showed that tenofovir diffused widely, especially in the digestive tract, liver and kidneys. Emtricitabine had a TPF above 100% in two-thirds of the tissues. Dolutegravir was poorly distributed to all tissues. Drug specificity was observed, with higher levels of exposure to tenofovir than to emtricitabine or dolutegravir. Tissue specificity was also observed, with strong penetration of the digestive tract and weak penetration of the brain. These data have important implications for future preclinical and clinical studies for developing new HIV therapies with the goal of an HIV cure.

Pharmacokinetics, Pharmacodynamics, and Tolerability of Opicapone in Healthy Chinese and Caucasian Subjects: An Open-Label, Single-Center, Phase1 Study.

IntroductionThis study evaluated the pharmacokinetics (PK) and pharmacodynamics (PD) of single and multiple doses of opicapone (OPC) in healthy Chinese and Caucasian subjects.MethodsIn this open-label, single-center, phase 1 study, eligible Chinese subjects received one of three OPC doses (25, 50, or 100 mg), and Caucasian subjects received either 25 or 50 mg of OPC. All subjects were administered a single dose of OPC, whereas subjects in the 50-mg OPC group continued to receive once-daily doses of 50 mg OPC for 10 days. The primary endpoint was to evaluate and compare the plasma concentrations and PK parameters of OPC and its main metabolite, and erythrocyte-soluble catechol-O-methyltransferase (S-COMT) activity in Chinese subjects with that of Caucasian subjects. The secondary endpoint was to evaluate the safety of OPC in Chinese subjects. The estimated results for geometric mean ratios (GMRs) were evaluated with the standard bioequivalence (BE) limits between 80% and 125% to evaluate the ethnic differences. All statistical analyses were performed using SAS version 9.4.ResultsIn total, 70 subjects (45 Chinese, 25 Caucasian) were enrolled; the majority of them were male (85.7%). The plasma exposure of both OPC and BIA 9-1103 increased in an approximately dose-proportional manner in both populations. Maximum S-COMT inhibition ranged from 79% to 95% after a single dose and was about 94% after a 10-day once-daily regimen in both populations. The point estimates of GMRs (Chinese/Caucasian) and 90% CI, except Cmax in 25-mg and 50-mg OPC groups, for PK and PD parameters were within 80% to 125%. Furthermore, no new risks or safety concerns associated with OPC were identified, indicating a tolerable safety profile in healthy Chinese subjects.ConclusionEthnicity had no significant impact on PK and PD parameters after single or multiple doses of OPC, and OPC was safe and tolerable in healthy Chinese subjects.Trial RegistrationChiCTR number, CTR20192230.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40120-021-00314-8.

Synthesis of novel combinatorial drug delivery system (nCDDS) for co-delivery of 5-Fluorouracil and Leucovorin calcium for colon targeting and controlled drug release

Objective: Purpose of the current study was to improve the oral effectiveness of 5-Fluorouracil (5-FU) by developing novel controlled, combinatorial drug delivery system (nCDDS) for co-delivery of 5-FU and Leucovorin (LC) for colon targeting. Significance: on the basis of results obtained, novel controlled, combinatorial drug delivery system (nCDDS) could be an effective strategy for the colon targeting of 5-FU and LC. Methods: Free radical polymerization method was tuned and used to fabricate this nCDDS. The nCDDS is synthesized in two steps, firstly synthesis of 5-fluoruracil/leucovorin calcium loaded nanogels and secondly, pre-synthesized 5-FU & LC loaded nanogels were dispersed in pectin based polymerized matrix hard gel. The nanogels and nCDD gels were characterized for network structure, thermal stability and surface morphology. Swelling and in-vitro release studies were carried out at different pH 1.2 and 7.4 both for naive nanogels and combined matrix gels. In-vivo study of combinatorial gel was performed on rabbits by using HPLC method to estimate plasma drug concentration and pharmacokinetics parameters. Results: Structure and thermal analysis confirmed the formation of stable polymeric network. SEM of nanogels and combinatorial gels showed that the spongy and rough edges particles and uniformly distributed in the combinatorial gel. The prepared nCDDS showed excellent water loving capacity and pH responsiveness. Combinatorial gel showed excellent characteristic for colonic delivery of drugs, which were confirmed by various in-vitro and in-vivo characterization. Acute oral toxicity study of combinatorial gel confirmed the biocompatible and non-toxic characteristics of developed formulation. Conclusion: Conclusively it can be found that nCDDS showed excellent properties regarding drug targeting in a controllable manner as compared to naive PEGylated nanogels.

Comparative analysis of pharmacokinetics and intestinal absorption of six alkaloids between Sanmiao Pills and Simiao Pills in rats

The present study investigated the differences in pharmacokinetics and intestinal absorption of six alkaloids in Sanmiao Pills and Simiao Pills in rats and explored the different efficacies of the two formulae. After oral administration of Sanmiao Pills and Simiao Pills in rats, blood samples were collected at different time points. Samples were prepared for the determination of six alkaloids in plasma by UPLC-MS/MS. The chromatography was performed on an ACE Excel 3 C_(18 )column with acetonitrile-0.1% formic acid in water as the mobile phase for gradient elution. Analytes were detected in the positive ion mode. Plasma concentrations and pharmacokinetic parameters were calculated. Intestinal absorption of alkaloids was investigated by single-pass intestinal perfusion and absorption parameters of ingredients were calculated. The results showed that the UPLC-MS/MS method for simultaneous determination of concentrations of six alkaloids in plasma was developed and validated by methodological investigations, such as specificity, calibration curves, precision, accuracy, recovery, matrix effect, and stability. The results of the pharmacokinetic assay revealed that C_(max) and AUC values of phellodendrine, berberine, magnoflorine, berberrubine, and jatrorrhizine in Simiao Pills were significantly increased, and CL/F values were reduced as compared with those in Sanmiao Pills, which indicated the increase in plasma concentrations of alkaloids. The intestinal absorption parameters K_(a )and P_(eff) values of phellodendrine, berberine, and jatrorrhizine in Simiao Pills were higher than those in Sanmiao Pills. The intestinal absorption and plasma concentrations of alkaloids in Simiao Pills were significantly higher than those in Sanmiao Pills, suggesting that the composition of Simiao Pills was more conducive to the alkaloids into the blood to resist inflammation and lower uric acid.

P029 Pharmacokinetic/Pharmacodynamic Analysis of Amiselimod, a Selective Sphingosine 1-Phosphate Receptor Modulator, in Healthy Subjects: Results From a Phase 1 Study.

Amiselimod is a selective sphingosine 1-phosphate receptor modulator in development for inflammatory bowel disease. It is converted to its active metabolite, amiselimod phosphate (amiselimod-P), and has a long half-life and slow accumulation to steady state. We evaluated a multiple-dose titration regimen to determine the plasma pharmacokinetic (PK) profile of amiselimod and amiselimod-P at steady state for the 0.4 mg QD therapeutic dose on day 13 and for the 0.8 mg QD supratherapeutic dose on day 26. We also investigated the pharmacodynamic (PD) effect of amiselimod on absolute lymphocyte counts (ALCs). A randomized, double-blind, multiple-dose, placebo-controlled, parallel study with a nested crossover design assessed amiselimod and amiselimod-P. Healthy adults received a single dose of placebo followed by oral amiselimod, which was upwardly titrated in doses ranging from 0.4 to 1.6 mg QD to rapidly achieve steady-state concentrations for the 0.4 mg QD and 0.8 mg QD doses within a 28-day treatment period. The PK parameters of amiselimod and amiselimod-P (on days 1, 13 and 26) included the geometric mean (geometric coefficient of variation percentage [CV%]) maximum plasma concentration (Cmax), median (minimum, maximum) time to Cmax (Tmax), geometric mean (geometric CV%) area under the concentration-time curve (AUC) from time 0 to the last measurable concentration, and geometric mean (geometric CV%) AUC from time 0 to 23.5 hours post dose (AUC0-23.5). Multidose PD were evaluated by changes in ALCs. The PK population included 95 amiselimod-treated participants and the PD population included 190 participants who received amiselimod or placebo. On day 13, the steady-state AUC and Cmax for amiselimod 0.4 mg QD increased by 10-fold for amiselimod and by 4-fold for amiselimod-P compared with day 1. On day 26, the steady-state AUC0-23.5 and Cmax for amiselimod 0.8 mg QD increased by 1.9-fold for amiselimod and by 1.8-fold for amiselimod-P compared with day 13. The median Tmax of plasma amiselimod and amiselimod-P were similar on all 3 days and were reached at 11 to 12 hours post dose for amiselimod and at 10 hours post dose for amiselimod-P. The mean ALCs for amiselimod exhibited a gradual decrease from pre-dose (1.681 × 103/uL) to a nadir of 0.424 × 103/uL on day 27. The abbreviated amiselimod dosing titration regimen reached steady state within 14 days for the therapeutic 0.4 mg QD regimen and within 26 days for the supratherapeutic 0.8 mg QD regimen; expected decreases in ALCs were observed following amiselimod.

Negligible Effect of Quercetin in the Pharmacokinetics of Sulfasalazine in Rats and Beagles: Metabolic Inactivation of the Interaction Potential of Quercetin with BCRP.

Breast cancer resistance protein (BCRP) mediates pharmacokinetic drug interactions. This study evaluated the potential of quercetin to inhibit and induce BCRP in vitro and in vivo. The inhibition of BCRP was investigated for quercetin and its metabolites using BCRP/mBcrp1-overexpressing MDCKII cells by flow cytometry. The induction of BCRP was investigated in LS174T cells using quantitative PCR. The expression of rat BCRP in rat small intestine, liver, and kidney was also measured after multiple administrations of quercetin in rats (50, 100, and 250 mg/kg, seven days). The in vivo pharmacokinetic changes of sulfasalazine following single or multiple administration of quercetin in rats and beagles were investigated. Although the induction effect of quercetin on BCRP was observed in vitro, the in vivo expression of rat BCRP was not changed by multiple quercetin administrations. Oral administration of quercetin did not affect the plasma concentration or pharmacokinetic parameters of sulfasalazine, regardless of dose and dosing period in either rats or beagles. In addition, the inhibitory effect of quercetin metabolites on BCRP/mBcrp1 was not observed. These results suggest that the in vivo drug interaction caused by quercetin via BCRP was negligible, and it may be related to the metabolic inactivation of quercetin for the inhibition of BCRP.