Aim To investigate the effect of diet upon liver function tests and serum lipids within the restricted environment of a Phase I unit.
Methods An open randomized three‐way crossover study was ...designed with subjects consuming three types of diet. The diets comprised, a balanced normal calorie diet, a high‐carbohydrate high‐calorie diet and a high‐fat high‐calorie diet. Each diet was consumed in a randomized sequence over 8 days with a recovery period of 14 days between periods. The blood concentrations of various laboratory parameters were measured at intervals throughout each dietary period and during the recovery periods.
Results Blood transaminase activity and triglyceride concentrations increased significantly whilst subjects consumed a high‐carbohydrate high‐calorie diet but not when fed either a high‐fat high‐calorie diet or a balanced normal calorie diet.
Conclusions The rises in transaminases and triglycerides were caused by the carbohydrate content of the diet rather than its calorific value. Sucrose rather than starch was the carbohydrate which caused the rise in transaminases and triglycerides. The importance of controlling diet in Phase I studies is stressed.
BackgroundDuring COVID19 pandemic, a small molecule antiviral agent PAXLOVIDTM was authorised for emergency use. The main antiviral component is nirmatrelvir, a coronavirus MPRO inhibitor, but it was ...combined with ritonavir to achieve persistent cell exposure. Respiratory virus usually infects through the nose and intranasal treatment is an attractive option for prophylactic treatment but challenging. Therefore, alternate strategies to deliver and retain nirmatrelvir within a treated cell is of great importance.AimThe aim of this project is to investigate antiviral effects of nirmatrelvir in a novel nanoemulsion formulation on coronavirus infected human primary nasal epithelium.MethodSeasonal coronavirus (HCOV-229E) was inoculated to the apical surface of air liquid interface (ALI) cultured human primary nasal epithelium. Viral load in apical wash was determined by a 50% tissue culture infectious dose (TCID50) assay and RT-PCR. Cell integrity, a marker of cell damage by virus infection, was measured as a transmembrane electrical resistance (TEER). 50 µL of nirmatrelvir (0.1 µM) prepared in water or as a nanoemulsion was applied to apical surface of ALI nasal epithelium for 10 min, and virus inoculum (0.2 MOI) was then applied to apical surface on top of the treatment for 1 hr. Apical surface wash with media was collected after treatment, then 1, 2 and 3 days post virus inoculation.ResultsHCoV viral load was maximal at Day 1 post inoculation. Analysis of the area under the curve (AUC) of viral load for 3 days post inoculation revealed that nirmatrelvir in water, nanoemulsion alone, and nirmatrelvir in nanoemulsion showed 69.5%, 89.8% and 100% inhibition of viral load vs. control, respectively. RT-PCR AUC was also inhibited by 13.5%, 52.2% and 100%, respectively, suggesting nirmatrelvir and nanoemulsion component showed synergistic effects. The nirmatrelvir in nanoemulsion also protected from virus induced reduction of TEER. The nirmatrelvir in nanoemulsion was well tolerated and not cytotoxic.ConclusionNovel nanoemulsion formulation of nirmatrelvir was found to show better antiviral effects against COV infection in human primary nasal epithelium.Please refer to page A291 for declarations of interest related to this abstract.
Troglitazone (TGZ), a 2,4-thiazolidinedione antidiabetic, causes hepatotoxicity in 1.9% of patients. TGZ is an inducer of, and substrate for, hepatic P450 3A. Microsomal metabolism yields a ...benzoquinone (TGZQ) and reactive intermediates. Kassahun et al. Kassahun et al. (2001) Chem. Res. Toxicol. 14, 62−70 have trapped the intermediates as thioester, thioether, and disulfide conjugates of glutathione and found five conjugates in rat bile. The thioether was substituted in the chromane moiety. We have investigated the effect of the P450 3A inducer, dexamethasone (DEX), on metabolism of TGZ and TGZQ in rats and assessed the compounds' cytotoxicity. TGZ-glucuronide and sulfonate were confirmed as principal biliary metabolites of TGZ (50 mg/kg, iv). Bile from noninduced animals also contained a TGZ-glutathione thioether adduct (ML3) but it was substituted in the thiazolidinedione moiety. Pretreatment with DEX (50 mg/kg/day for 3 days) resulted in a 2−5-fold increase in the biliary concentration of ML3 and a 2-fold increase in the concentration of TGZQ, which was commensurate with the induction of hepatic P450 3A. Three of the known glutathione-conjugated metabolites were also found. TGZQ (50 mg/kg, iv) was metabolized to an analogue of one of the TGZ-glutathione thioesters and a glutathione adduct of TGZQ hydroquinone after DEX pretreatment. TGZ quinol glucuronide was a biliary metabolite of TGZ and TGZQ. Its formation would represent deactivation of TGZQ. TGZ was toxic to rat hepatocytes and Hep-G2 cells at concentrations exceeding 50 and 25 μM, respectively, after 24 h. In contrast, TGZQ was nontoxic to rat hepatocytes and toxic to Hep G2 cells only at concentrations exceeding 100 μM. Our results show that TGZQ as well as TGZ yields reactive metabolites in vivo, and that bioactivation is enhanced by induction of P450 3A. However, hepatotoxicity is unlikely to be due to either TGZQ or its metabolites.
IntroductionControlled human infection models (CHIMs) involve the deliberate exposure of individuals to a pathogen in a controlled environment. Respiratory organism CHIMs have been utilised to ...further understanding on the kinetics of infection or host-pathogen immunobiology plus enabling expedited testing of vaccines and therapeutics. A SARS-CoV-2 CHIM has been undertaken in seronegative volunteers utilising a dose of 10TCID50 pre-Alpha virus strain. Sustained infection was seen in 53% (18/34) volunteers with infectious virus persisting for on average 10 days.1 Development of a seropositive model is necessary to allow full assessment of immune correlates of protection (CoP) and enable use for vaccine and therapeutic development given the increasing global seroprevalence to SARS-CoV-2.Methods36 healthy, SARS-CoV-2 seropositive, 18–30-year-old volunteers were inoculated intranasally with increasing doses of pre-Alpha SARS-CoV-2 virus (same as used in the seronegative CHIM) in a sequential fashion up to a dose of 105 TCID50. Volunteers were quarantined for at least 14 days after inoculation and until 12-hourly oropharyngeal/nasal swabs were negative for viable virus. The primary objective being identification of a safe, well-tolerated dose that induced infection in 50% of volunteers.ResultsOnly five of 36 (13.9%) volunteers developed infection despite dose escalation up to 105TCID50. Infection kinetics differed compared to the seronegative CHIM, with volunteers demonstrating transient episodes of PCR positivity only (median duration 12 hours). Comparison of pre-inoculation samples identified significantly lower baseline mucosal and systemic SARS-CoV-2 specific antibody titres and lower peripheral IFN-y responses against a CD8+ T cell SARS-CoV-2 peptide pool in infected volunteers.Abstract S109 Figure 1Positive PCR during quarantine. Demonstrates all swabs taken during the quarantine period. Coloured squares denote detection of SARS-CoV-2 by qPCR with viral titre values presented. The 5 volunteers considered to demonstrate Transient infection (TI) are labelled. All other SARS CoV-2 positive swabs were considered to represent residual inoculum following inoculation, with initial viral detection occurring on Day 1 (denoted by thick black line) and subsequent rapid decline in viral titresConclusionsOur inability to reproduce the sustained infection kinetic seen in the seronegative CHIM despite a significant dose escalation using the same viral strain demonstrates the potent protective immunity induced by homologous vaccination and homologous/heterologous prior SARS CoV-2 infection. Our model has identified credible CoP against infection with work ongoing to interrogate post exposure immunity. Model development to induce sufficient infection rates for product evaluation and further validation of our identified CoP is required.ReferenceKillingley B, et al. Safety, tolerability and viral kinetics during SARS-CoV-2 human challenge in young adults. Nature Medicine 2022;28(5):1031–1041.Please refer to page A287 for declarations of interest related to this abstract.
A double-blind, randomized, placebo-controlled study was conducted in 14 healthy male volunteers to assess the effects of sertraline on the pharmacokinetics and pharmacodynamics of carbamazepine.
...Subjects received carbamazepine 200 mg once daily for 2 days and every 12 hours thereafter. On Days 16 to 32, subjects also received either sertraline or placebo daily. The dose of sertraline was increased from 50 to 200 mg daily over 7 days; the 200-mg dose was given for 10 days. Samples for pharmacokinetic analyses were obtained on Days 15 and 32; trough plasma concentrations of carbamazepine and its principal metabolite, carbamazepine-10, 11-epoxide (CBZ-E), were determined daily beginning on Day 13. Cognitive function testing was performed on Day 1 before carbamazepine dosing (baseline), Day 15 (carbamazepine alone), and Day 32 (carbamazepine plus sertraline or placebo).
There were no significant differences between the sertraline and placebo groups in any of the pharmacokinetic parameters for carbamazepine or CBZ-E. Carbamazepine alone impaired cognitive function. The addition of sertraline did not potentiate these effects. Side effects were reported by 2 subjects in each group, but none were severe.
These findings indicate that sertraline does not affect the pharmacokinetics of carbamazepine or its principal metabolite and does not potentiate the cognitive effects of carbamazepine.
Wepresent a method for investigating the dynamic pharmacological modulation of pain-related brain activity, measured by BOLD-contrast fMRI. Noxious thermal stimulation was combined with a single ...infusion and washout of remifentanil, a short-acting opioid analgesic agent. The temporal profile of the effect site concentration of remifentanil, estimated from a pharmacokinetic model, was incorporated into a linear model of the fMRI data. The methodology was tested in nine healthy male subjects. During each imaging session the subjects received noxious thermal stimulation to the back of the left hand, prior to infusion, during infusion to a remifentanil effect site concentration of 1.0 ng/ml, and during washout of the remifentanil. Infusions were repeated with saline. Remifentanil-induced analgesia was confirmed from subjective pain intensity scores. Pain-related brain activity was identified in a matrix of regions using a linear model of the transient BOLD responses to noxious stimulation. Of those regions, there was a significant fractional reduction in the amplitude of the pain-related BOLD response in the insular cortex contralateral to the stimulus, the ipsilateral insular cortex, and the anterior cingulate cortex. Statistical parametric mapping of the component of pain-related BOLD responses that was linearly scaled by remifentanil concentration confirmed the contralateral insular cortex as the pain-processing region most significantly modulated by remifentanil compared to saline. The mapping of specific modulation of pain-related brain activity is directly relevant for understanding pharmacological analgesia. The method of examining time-dependent pharmacological modulation of specific brain activity may be generalized to other drugs that modulate brain activity other than that associated with pain.
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