Low Plasma Concentrations Research Articles

Bioadhesive film for the delivery of local anesthetics to the buccal mucosa: ex-vivo and in-vivo evaluation

The aim of this work was the preparation and characterization of two bioadhesive films (with different drug loadings) containing a combination of lidocaine and prilocaine hydrochloride to be applied on the buccal mucosa to reduce the pain sensation associated with needle insertion during dental procedures. The films were tested ex-vivo to determine the amount of drug permeated/retained in buccal mucosa, and, in-vivo to assess the extent and duration of anesthetic effect on the mucosa and pharmacokinetic parameters. As a reference, the commercial formulation EMLA® cream was used. Ex-vivo studies were conducted on porcine esophageal epithelium, an accepted model for buccal mucosa, and in-vivo studies on human volunteers. The ex-vivo results obtained show that the retention of both drugs into the mucosa resulted comparable after the application of the films or EMLA® cream for 10 min; on the contrary, the amounts of drug permeated from the commercial formulation was higher, suggesting the possibility to achieve systemic effect. In-vivo experiments showed that the intensity of anesthesia, evaluated by VAS during needle insertion, was much higher for EMLA® cream (the median value was zero for EMLA® and 0.15–0.3 cm for the two films); however, the film and EMLA® cream resulted equivalent in terms of duration of anesthesia, from 25 to 40 min. The pharmacokinetic study showed that both films tested produced very low plasma concentration (zero for most of experimental data point), thus guaranteeing no risk of systemic effects, whereas EMLA® cream demonstrated measurable plasma levels for both drugs (lidocaine Cmax was 4 ng/ml, prilocaine Cmax was 1.5 ng/ml). Moreover, a correlation between ex-vivo drug tissue concentration and duration of the anesthetic effect in-vivo was found. Although this correlation is limited to a small number of formulations, it supports the validity of pig esophageal epithelium in the development of formulation to be used on human buccal mucosa.

Vaginal administration of 17-alpha hydroxyprogesterone caproate appears to be safe in non-pregnant female rats and rabbits

Intramuscular (250 mg once weekly) or subcutaneous (275 mg once weekly) injections of 17-hydroxyprogesterone caproate (17-OHPC) has been utilised to prevent recurent spontaneous preterm birth in pregnant women with a short cervix or those with a prior preterm birth but its efficacy in these conditions has been questioned. It is unclear whether adequate concentrations of 17-OHPC reach the suspected target organs such as the cervix and uterus following either IM or SC administration. The objective of this study was to determine feasibility and safety of vaginal administration of 17-OHPC in adult female Sprague Dawley rats and female New Zealand rabbits. Gels containing 17-OHPC were administered intravaginally to rats and rabbits for 10 consecutive days. After the last dose, serial blood samples and terminal uterine and adipose tissue samples were collected. 17-OHPC concentrations were measured by LC-MS-MS. Tissue histology showed that intravaginal administration of 17-OHPC was safe. There was no renal or hepatic toxicity as measured by liver function and kidney function tests. Intravaginal administration of 17-OHPC resulted in low systemic plasma concentrations but substantially higher uterus and adipose tissue concentrations of 17-OHPC. Composition of the formulation affected the tissue distribution of 17-OHPC. Future studies warrant further evaluation of the effect and safety of daily intravaginal administration of 17-OHPC gel in pregnant animals.

Prophylactic Unfractionated Heparin in Antepartum Hospitalizations: A Randomized Controlled Trial

(Obstet Gynecol. 2024;144(1):118–125. doi: 10.1097/AOG.0000000000005599) Obstetric venous thromboembolism (VTE) is a significant cause of maternal morbidity and mortality, particularly in cases of prolonged antepartum hospitalizations. Comprehensive thromboembolism prevention strategies have helped reduce maternal mortality from thromboembolism. Current recommendations emphasize expanded heparin prophylaxis during antepartum hospitalizations to mitigate VTE risks. However, there is a lack of data on how pregnancy-induced physiological changes affect unfractionated heparin (UFH) disposition, potentially necessitating higher dosing during pregnancy. Studies suggest pregnant patients may require increased heparin doses due to lower peak plasma concentrations and altered coagulation parameters.

Delivery of JAL-TA9 to the brain by nasal application

We have reported on two Catalytides (Catalytic peptides), JAL-TA9 (YKGSGFRMI) and ANA-TA9 (SKGQAYRMI). Both peptides belong to the Tob/BTG family proteins and cleave Aβ42. Although Catalytides must be delivered to the brain parenchyma to treat Alzheimer's disease, the blood-brain barrier (BBB) limits their entry into the brain from the systemic circulation. Thus, we evaluated the direct route of ANA-TA9 from the nasal cavity to the brain to bypass the BBB. In this study, we present our findings on JAL-TA9. Animal studies using rats and mice clarified that the plasma clearance of JAL-TA9 was more rapid than its in vitro degradation in plasma, whole blood, and cerebrospinal fluid (CSF). After nasal administration of JAL-TA9, brain concentrations were significantly higher than after intraperitoneal administration, despite much lower plasma concentration. This observation strongly suggests direct delivery of JAL-TA9 to the brain from the nasal cavity. Similar findings were observed for its transport to CSF after nasal and intravenous administration. The concentration of JAL-TA9 in the olfactory bulb peaked at 5 ‍min, while those in the frontal brain peaked at 30 ‍min and in the occipital brain at 60 ‍min. In conclusion, JAL-TA9 was efficiently delivered to the brain by nasal application compared to other routes.

Plasma statin concentrations do not correlate with statin-induced myalgia

Abstract Aims Statins are essential in cardiovascular prevention. Although well-tolerated, patient adherence is often suboptimal due to experienced musculoskeletal symptoms ranging from mild myalgia to rare life-threatening rhabdomyolysis. This study aimed to investigate the relationship between plasma concentrations of statin metabolites in patients experiencing myalgia without rhabdomyolysis. Methods and results Plasma concentrations of statin metabolites were quantitatively assessed using mass spectrometry across three case-control cohorts evaluating statin-induced myalgia. The analysis included a total of 373 patients from the MILANO study (N=85 with self -reported myalgia), the MONTREAL study (N=248 with clinically verified myalgia) and the STOMP study (N=40 with rechallenge-verified statin-induced myalgia). STOMP found no significant difference in the plasma concentrations of statin metabolites between statin naïve patients with myalgia (N=12) taking atorvastatin 80 mg daily and asymptomatic controls (N=28), including upon subsequent statin rechallenge. Both the MILANO and MONTREAL studies showed lower plasma concentrations of statin metabolites in patients with myalgias compared to controls. MILANO showed a significant difference in rosuvastatin lactone concentration in patients with myalgias compared to asymptomatic controls (P = 0.025). Similarly, MONTREAL showed significantly lower mean atorvastatin metabolite concentrations in affected patients versus controls (P values ranging from 0.0073 to 0.037). Atorvastatin dosages in MONTREAL ranged from 5 to 80 mg daily, the most frequent regimens being 20 mg (27% in cases; 24% in controls) and 40 mg (33% in cases; 37% in controls). Creatine kinase levels were measured in all cohorts and were not different between cases and controls. Conclusion Development of myalgias in patients with normal creatine kinase levels is not associated with higher statin metabolite plasma concentrations. Myalgias during statin therapy are not caused by pharmacokinetic abnormalities.

Bleeding Events Associated with Rivaroxaban Therapy in Naive Patients with Nonvalvular Atrial Fibrillation: A Longitudinal Study from a Genetic Perspective with INR Follow-Up.

Background and Objectives: Rivaroxaban is a direct-acting anticoagulant used to prevent stroke in patients with atrial fibrillation. Rivaroxaban is a substrate for P-glycoprotein, which is encoded by the ABCB1 gene. Rivaroxaban is also metabolized by the CYP3A5 gene. Therefore, the current study is carried out to study the effects of polymorphisms in the ABCB1 and CYP3A5 genes, which may affect the plasma levels of rivaroxaban, with subsequent clinical outcomes (bleeding events) associated with the therapy. Materials and Methods: The study was conducted on 66 naive patients with atrial fibrillation treated with rivaroxaban. Blood samples of rivaroxaban were taken at 3 h and after 1 month following the administration of the drug to measure plasma levels. The blood level of rivaroxaban was measured with an HPLC-UV detector. Sanger sequencing was used to find polymorphisms in the targeted genes. Coagulation parameters were measured at 3 h and after 1 month of administration of rivaroxaban. Frequencies of bleeding events were recorded throughout the one-month course of drug therapy. Results: The heterozygous and homozygous mutant genotypes of ABCB1 (rs2032582, rs1045642, rs1128503, and rs4148738) and CYP3A5 (rs776746) showed lower plasma concentrations as compared to the wild-type genotype. ABCB1 (rs2032582, rs1045642, rs1128503, and rs4148738) and CYP3A5 (rs776746) gene polymorphisms had a statistically significant impact on the plasma concentration of rivaroxaban among the heterozygous and homozygous mutant genotypes compared to the wild-type genotype. The heterozygous variant of ABCB1 and homozygous variant of CYP3A5 suffered more events of bleeding. Conclusions: It was concluded that ABCB1 (rs2032582, rs1045642, rs1128503, and rs4148738) and CYP3A5 (rs776746) gene polymorphisms had a significant impact on the plasma levels of rivaroxaban in patients treated for atrial fibrillation on day three as well as after one month of the therapy. The lowest plasma levels were observed in patients with a homozygous variant of ABCB1 (rs2032582, rs1045642, or rs4148738) along with the CYP3A5*1/*3 allele. The heterozygous variant of ABCB1 SNPs and homozygous variant of CYP3A5 SNPs suffered more events of bleeding.

Effect of Using Prickly Pear Seed Cake (Opuntia ficus indica L.) on Growth Performance, Digestibility, Physiological and Histometric Parameters in Rabbits

Prickly pear (Opuntia ficus indica L.) could be used in rabbit nutrition in compliance with circular economy principles, global warming issues, and reduction of production costs. This study aims to evaluate the effects of dietary incorporation of prickly pear seed cake (PPSC) on growth, physiological, and histometric parameters in rabbits. A total of 105 rabbits were divided into three experimental groups (n = 35) and fed different diets: a commercial feed (C group), the same feed with alfalfa replaced by PPSC at 10% (10PP group), and at 20% (20PP group). They were group-housed in cages with 5 animals per cage from weaning until slaughtering. While body weights and weight gains were similar in all groups, the coefficients of nutrient digestibility of dry matter, fibers, and ashes, as well as the characteristics of intestinal villi, were improved in the 10PP group compared to the others (p < 0.05). The 20PP group showed a reduction in perirenal and interscapular fat (p < 0.05), as well as lower plasma concentrations of triglycerides and cholesterol compared to the C group (p < 0.001). In conclusion, PPSC can be incorporated into the diets of growing rabbits up to 20% as a partial substitute for alfalfa without the impairment of growth performance. Additionally, the inclusion of PPSC enhanced nutrient digestibility and increased the intestinal absorption surface area.

Cold plasma irradiation of chitosan: A straight pathway to selective antitumor therapy

Plasma-activated chitosan (PAC) colloids for cancer treatment were obtained by using the cold atmospheric plasma technique. Chitosan solutions were irradiated by plasma ignited in argon gas and in a mixture of argon with nitrogen and oxygen gases in certain ratios. The structural modifications of chitosan and the chemical species generated in plasma were investigated by EPR, LC-MS/MS, XRD, DLS, and TGA methods. The cell viability test showed a selective cytotoxic effect on human breast carcinoma cells (MCF-7), while the human mammary epithelial cells (MCF-10A) were left unharmed. The cytotoxic effect was attributed mainly to chitooligosaccharides, but also to a synergistic effect with other compounds generated in very low concentrations in plasma, such as glyceric acid, ethyl acetate, or tricarballylic acid. The plasma irradiation improved the antioxidant activity and mucoadhesivity, while not affecting the hemocompatibility investigated by a standard hemolysis ex vivo test on mice blood. Moreover, the in vivo biocompatibility investigation at intraperitoneal administration of PAC in mice showed no statistically significant changes in the hematologic, biochemical, and immune system parameters, and no morphologic alterations of the liver and kidney. All these data indicate the cold plasma activation of chitosan as a straight method to produce biocompatible, antitumor systems.

7787 Primary Aldosteronism Medical Treatment Outcomes (PAMO): An International Consensus on Outcome Assessment Criteria and Multicentre Study

Abstract Disclosure: J. Yang: None. J. Burrello: None. J. Goi: None. T.A. Williams: None. W.F. Young: Consulting Fee; Self; Arena Pharmaceuticals, Inc.. Other; Self; Crinetics Pharmaceuticals. P.J. Fuller: None. P. Investigators: None. Primary aldosteronism (PA) is the most common endocrine cause of hypertension. Mineralocorticoid receptor antagonists, at adequate doses, lower blood pressure and cardiovascular risk in patients with PA. However, there is a lack of a standardized approach to medical therapy and subsequent outcomes assessment. We aimed to: 1) establish criteria for assessing outcomes of targeted medical treatment of PA, and 2) evaluate outcomes using these criteria across an international cohort. A panel of 31 PA experts from 31 centres across four continents used the Delphi method, including three rounds of online questionnaires, to reach consensus. Clinical data were then collected from consecutive patients with PA who started targeted medical treatment between 2016 and 2021 at the participating centres. Consensus was reached for six outcomes, including complete, partial, or absent biochemical response, and complete, partial, or absent clinical response. “Complete biochemical response” was defined as “correction of hypokalemia without potassium supplementation, and normalization of plasma renin activity or concentration”; while “absent biochemical response” was defined as “persistent hypokalemia and/or persistently suppressed or low plasma renin activity or concentration without change from baseline”. “Complete clinical response” was defined as “normal blood pressure without additional antihypertensive medications”; while “absent clinical response” was defined as “the same or increased blood pressure compared to before targeted treatment with same or more antihypertensive medications, not counting targeted therapy”. Of 1483 patients (mean age 52y, 48% female) from 28 centers, 232 (16%) had a complete clinical response, and 719 (49%) had a complete biochemical response at the most recent follow-up (median 29 months after treatment initiation). Compared to those with partial or absent clinical response, patients with complete clinical response had a significantly higher proportion of women and lower proportion with diabetes, stroke or left ventricular hypertrophy. They also had a significantly shorter duration of hypertension, lower BMI, higher eGFR and lower defined daily dose of antihypertensives at baseline. In contrast, these differences were not observed in those with a complete, partial or absent biochemical response. The defined daily dose of targeted therapy did not differ across the various response categories. In conclusion, we have established an international expert consensus for standardized criteria to evaluate the response to targeted medical treatment of PA, facilitate comparisons of outcome data and guide clinicians who manage PA. In a retrospective international cohort, less than half of medically-treated patients reached the established biochemical treatment targets. Further work is needed to increase the rate of complete response. Presentation: 6/3/2024

A finasteride patch for the treatment of androgenetic alopecia: A study of promoting permeability strategy using synthetic novel O-acylmenthols combined with ion-pair

Currently, finasteride (FIN) is approved to treat androgenetic alopecia only orally, and the application of FIN in transdermal drug delivery system (TDDS) has introduced a new approach for treating the disease. This study was aimed to develop a FIN transdermal patch for the treatment of androgenetic alopecia（AGA） by combing ion-pair and O-acylmenthols (AM) as chemical permeation enhancers (CPEs). The formulation of patch was optimized though single-factor investigation and Box-Behnken design. The pharmacokinetics and androgenetic alopecia pharmacodynamics of the patch were evaluated. Additionally, the permeability enhancement mechanisms of ion-pair and AMs were explored at both the patch and skin levels. The effects of ion-pair and AMs on the patch were characterized by rheology study, FTIR, and molecular docking, and the effects on the skin were assessed through ATR-FTIR, Raman study, DSC, CLSM and molecular dynamics. The finalized formulation of FIN patches was consisted of 5 % (w/w) synthetic FIN-CA (Citric Acid), 6 % MT-C6 as CPEs, 25-AAOH as a pressure-sensitive adhesive (PSA), with a patch thickness of 80 ± 5 μm. The final Q24 h is 78.22 ± 5.18 μg/cm2. Based on the high FIN permeability, the pharmacokinetic analysis revealed that the FIN patch group exhibited a slower absorption rate (tmax = 7.3 ± 2.7 h), lower peak plasma concentration and slower metabolic rate (t1/2 = 6.2 ± 0.8 h, MRT0-t = 26.0 ± 7.8 h) compared to the oral group. Moreover, the FIN patch also demonstrated the same effect as the oral group in promoting hair growth in AGA mice. The results indicated that both FIN-CA and AMs could enhance the fluidity of the PSA and weaken the interaction between FIN-CA and PSA, thereby promoting the release of the FIN from the patch. The interaction sites on the skin for ion-pair and the four AMs were found in the stratum corneum (SC) of the skin, disrupting the tight arrangement of stratum corneum lipids. This study serves as a reference for the multi-pathway administration of FIN and the combination of ion-pair with AMs to enhance drug permeation.

Pharmacokinetic and pharmacodynamic evaluation of various vasopressin doses and routes of administration in a neonatal piglet model

Epinephrine is the only recommended vasopressor during neonatal cardiopulmonary resuscitation. However, there are concerns about the potential adverse effects of epinephrine, which might hamper efficacy during cardiopulmonary resuscitation. An alternative might be vasopressin, which has a preferable adverse effect profile, however, its optimal dose and route of administration is unknown. We aimed to compare the pharmacodynamics and pharmacokinetics of various vasopressin doses administered via intravenous (IV), intraosseous (IO), endotracheal (ETT), and intranasal (IN) routes in healthy neonatal piglets. Forty-four post-transitional piglets (1–3 days of age) were anesthetized, intubated via a tracheostomy, and randomized to receive vasopressin via intravenous (control), IO, ETT, or IN route. Heart rate (HR), arterial blood pressure, carotid blood flow, and cardiac function (e.g., stroke volume, ejection fraction) were continuously recorded throughout the experiment. Blood was collected prior to drug administration and throughout the observation period for pharmacodynamics and pharmacokinetic analysis. Significant changes in hemodynamic parameters were observed following IO administration of vasopressin while pharmacokinetic parameters were not different between IV and IO vasopressin. Administration of vasopressin via ETT or IN did not change hemodynamic parameters and had significantly lower maximum plasma concentrations and systemic absorption compared to piglets administered IV vasopressin (p < 0.05). The IV and IO routes appear the most effective for vasopressin administration in neonatal piglets, while the ETT and IN routes appear unsuitable for vasopressin administration.

Pharmacokinetic interaction of quetiapine and lamotrigine – victim and perpetrator?

ABSTRACT Objective We aimed to investigate the ambiguous findings of earlier research regarding the reduction of quetiapine plasma levels when combined with lamotrigine, most likely via UDP-glucuronosyltransferase induction by lamotrigine. Methods One thousand one hundred and fifty samples, divided into four groups of patients receiving either quetiapine immediate- (IR) or extended-release (XR) without or in combination with lamotrigine were compared regarding absolute and dose-adjusted plasma concentrations. Furthermore, samples of intra-individual controls were analyzed. Results Patients receiving quetiapine IR in combination with lamotrigine showed 31% lower plasma (p = 0.002) and 23% lower dose-adjusted plasma concentrations (p = 0.004) compared to those receiving IR monotherapy. The proportion of patients with quetiapine plasma concentrations below the lower limit of the therapeutic reference range was 50% and 30% in the combination group and in patients receiving monotherapy, respectively (p = 0.03). However, no significant differences regarding plasma concentration (p = 0.13) and dose-adjusted plasma concentration (p = 0.42) were observed in patients with combination vs. monotherapy with the XR formulation of quetiapine. In the intra-individual controls, no trends could be identified, possibly due to insufficient number of samples (p > 0.05). Conclusions The combination of quetiapine IR with lamotrigine is associated with significantly lower drug concentrations of quetiapine, potentially impacting quetiapine effectiveness. For quetiapine ER, a significant interaction is less likely.

B-137 Sepsis risk prediction using machine learning (ML) and routine blood markers up to 1 week before emergency admission

Abstract Background Sepsis is a major global health concern, responsible for approximately 50 million cases and 11 million deaths annually, representing 20% of global mortality. It is the leading cause of hospital readmissions and deaths, with associated costs exceeding $38 billion per year. Alarmingly, 80% of sepsis cases occur outside the hospital, and 70% of patients visit an outpatient facility within a week of admission. Early diagnosis and appropriate treatment could prevent 80% of sepsis-related deaths. Our study demonstrates that machine learning models hold significant promise in identifying sepsis risks using routine blood tests up to 1 week before admission. Methods For our study, we utilized a dataset of over 25,000 patient records, including both sepsis and non-sepsis cases, sourced from MIMIC-IV (version 2.2), a comprehensive electronic health record dataset from Beth Israel Deaconess Medical Center, Boston, MA. We employed a gradient boosted model with 300 trees, a maximal depth of 30 layers, and gain ratio as the criterion for attribute selection. The model's performance was evaluated using 10-fold cross-validation, demonstrating optimal performance. Input parameters included age, gender, and results of routine blood markers such as complete blood counts, differential counts, comprehensive metabolic panels, and lipid panels recorded up to 1 week before sepsis diagnosis. Results Our model achieved remarkable predictive accuracy for sepsis risk, with an area under the receiver operating characteristic curve (AUC) of 0.99 and accuracy of 0.99. Notably, the model achieved 1.0 sensitivity, 0.99 specificity, 0.99 positive predictive value, 1.0 negative predictive value, 0.99 F measure, and 0.99 Youden index. Calcium, protein, liver enzymes, hematocrit, white blood cells, and cholesterol were identified as key contributors to sepsis risk prediction. Importantly, prediction accuracy remained consistent up to 1 week prior to diagnosis. Conclusions In conclusion, dysregulated intracellular calcium handling during sepsis is associated with an intensified inflammatory response, cellular death, and subsequent organ dysfunction. Low serum protein levels, particularly albumin, are linked to poor outcomes in sepsis. Recent studies have identified liver dysfunction as an early event in sepsis, underscoring its significance in the disease process. Elevated bilirubin levels are associated with an increased risk of mortality. Low hematocrit (HCT) levels are linked to higher 30-day mortality and serve as an independent prognostic biomarker in sepsis. Monocytes play a significant role in sepsis pathophysiology, undergoing various changes including preserved phagocytic activity, increased reactive oxygen species and nitric oxide generation, and decreased production of inflammatory cytokines such as IL-6 and TNF-alpha. Septic patients often exhibit lymphopenia, affecting CD4 and CD8 T cells, B cells, and natural killer (NK) cells. Hypocholesterolemia is common in sepsis and serves as an important early prognostic factor, with low plasma concentrations associated with poor outcomes. Since every hour of delayed treatment increases the risk of death by 4%-9%, changes in routine blood markers detected by machine learning models can provide early indications of impending sepsis up to 1 week before diagnosis.

Role of In Vitro Tests in the Characterisation of Locally Applied, Locally Acting Drugs in the Throat: Application to Flurbiprofen.

Background/Objectives: For locally applied, locally acting generic drug products, comparison to an originator product based on systemic exposure is usually not feasible due to low plasma concentrations and inadequate reflection of local exposure at the site of action. Where a validated PD model exists, a comparative clinical study can be performed in healthy subjects; where no surrogate endpoint is available, patients with the relevant indication need to be enrolled, with all the associated factors which could result in lack of sensitivity. Even though the need for alternative in vitro approaches has been acknowledged by both industry and regulatory bodies, the complexity of in vivo drug delivery processes makes the development of guidance documents particularly difficult. Our objective was to present in vitro approaches less classically used and to address in vivo relevance of the selected tests. Methods: This article analyses current regulatory approaches in Europe and the U.S., and highlights the key advantages of in vitro tests in terms of their sensitivity, reliability, reproducibility and in vivo relevance using locally applied flurbiprofen in various formulations. Results: The in vitro esophageal retention (IVOR) model demonstrates that the first 6-10 min after application of different flurbiprofen formulations is important for their comparison and also offers the best correlation with in vivo data using the partial area under the concentration-time curves (pAUCs). Rheological evaluations further demonstrated that the mucoadhesive properties of the gel spray formulation are based on interaction with mucin. Conclusions: Designing a relevant in vitro test requires adequate evaluation of the complexity of the drug substance, drug product, dosing conditions and delivery processes.

Brain Exposure to the Macrocyclic ALK Inhibitor Zotizalkib is Restricted by ABCB1, and Its Plasma Disposition is Affected by Mouse Carboxylesterase 1c.

Zotizalkib (TPX-0131), a fourth-generation macrocyclic anaplastic lymphoma kinase (ALK) inhibitor, is designed to overcome resistance due to secondary ALK mutations in non-small cell lung cancer (NSCLC). We here evaluated the pharmacokinetic roles of the ABCB1 (P-gp/MDR1) and ABCG2 (BCRP) efflux transporters, OATP1 influx transporters and the metabolizing enzymes CES1 and CYP3A in plasma and tissue disposition of zotizalkib after oral administration in relevant mouse models. Zotizalkib was efficiently transported by hABCB1 in vitro. In vivo, a significant ∼9-fold higher brain-to-plasma ratio was observed in Abcb1a/b-/- and Abcb1a/b;Abcg2-/- compared to wild-type mice. No change in brain disposition was observed in Abcg2-/- mice, suggesting that mAbcb1a/b markedly restricts the brain accumulation of zotizalkib. ABCB1-mediated efflux of zotizalkib was completely inhibited by elacridar, a dual ABCB1/ABCG2 inhibitor, increasing brain exposure without any signs of acute CNS-related toxicities. In Oatp1a/b-/- mice, no marked changes in plasma exposure or tissue-to-plasma ratios were observed, indicating that zotizalkib is not a substantial in vivo substrate for mOatp1a/b. Zotizalkib may further be metabolized by CYP3A4 but only noticeably at low plasma concentrations. In Ces1-/- mice, a 2.5-fold lower plasma exposure was seen compared to wild-type, without alterations in tissue distribution. This suggests increased plasma retention of zotizalkib by binding to the abundant mouse plasma Ces1c. Notably, the hepatic expression of human CES1 did not affect zotizalkib plasma exposure or tissue distribution. The obtained pharmacokinetic insights may be useful for the further development and optimization of therapeutic efficacy and safety of zotizalkib and related compact macrocyclic ALK inhibitors.

Standardization and application of ARMS TaqMan real-time PCR for screening of folate metabolism genes in Han Chinese.

Folate has antioxidant properties, and low concentration in seminal plasma may be associated with increased DNA damage in sperm. Mutations of the methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) genes, including MTHFR C677T (rs1801133), MTHFR A1298C (rs1801131), and MTRR A66G (rs1801394), can lead to decreased activity of the encoded folate metabolic enzymes, thereby affecting male reproduction. The current SNP detection methods commonly used in clinical practice have some shortcomings, such as long time-consuming, complex detection steps, or high cost. The purpose of this study was to establish a simple, time-saving, sensitive, accurate, and easy to clinical popularization method for folate metabolism gene detection. We combined ARMS-PCR with TaqMan fluorescent probe to establish an ARMS TaqMan real-time PCR detection method. According to the variation of rs1801131, rs1801133, and rs1801394, two specific primers (one wild type and one mutant) were designed. Mismatched nucleotides were introduced at the penultimate or third position to improve the specificity of the primer. Specific TaqMan probe was introduced to detect PCR products to improve the sensitivity of the method. The results showed that the sensitivity of ARMS TaqMan real-time PCR in SNP genotyping was 1ng, and the accuracy was 100%. A total of 249 clinical samples were detected by the established method, and the correlation between three SNPs and semen quality was analyzed. We found that individuals carrying the AG+GG genotype of rs1801394 had a lower risk of abnormal semen quality. In conclusion, we developed a highly sensitive, accurate, rapid, and easy to be popularized method for detecting SNPs of rs1801394, rs1801131, and rs1801133. ARMS TaqMan real-time PCR is a reliable SNP genotyping method in folate metabolism genes.

Whole Body PhysiologicallyBased Pharmacokinetic Model to Explain A Patient With Drug-Drug Interaction Between Voriconazole and Flucloxacillin.

Voriconazole administered concomitantly with flucloxacillin may result in subtherapeutic plasma concentrations as shown in a patient with Staphylococcus aureus sepsis and a probable pulmonary aspergillosis. After switching our patient to posaconazole, therapeutic concentrations were reached. The aim of this study was to first test our hypothesis that flucloxacillin competes with voriconazole not posaconazole for binding to albumin ex vivo, leading to lower total concentrations in plasma. A physiologicallybased pharmacokinetic (PBPK) model was then applied to predict the mechanism of action of the drug-drug interaction (DDI). The model included non-linear hepatic metabolism and the effect of a severe infectious disease on cytochrome P450 (CYP) enzymes activity. The unbound voriconazole concentration remained unchanged in plasma after adding flucloxacillin, thereby rejecting our hypothesis of albumin-binding site competition. The PBPK model was able to adequately predict the plasma concentration of both voriconazole and posaconazole over time in healthy volunteers. Upregulation of CYP3A4, CYP2C9, and CYP2C19 through the pregnane X receptor (PXR) gene by flucloxacillin resulted in decreased voriconazole plasma concentrations, reflecting the DDI observations in our patient. Posaconazole metabolism was not affected, or was only limitedly affected, by the changes through the PXR gene, which agrees with the observed plasma concentrations within the target range in our patient. Ex vivo experiments reported that the unbound voriconazole plasma concentration remained unchanged after adding flucloxacillin. The PBPK model describes the potential mechanism driving the drug-drug and drug-disease interaction of voriconazole and flucloxacillin, highlighting the large substantial influence of flucloxacillin on the PXR gene and the influence of infection on voriconazole plasma concentrations, and suggests a more limited effect on other triazoles.

Transdermal Fentanyl in Patients with Cachexia-A Scoping Review.

Cachectic patients frequently require transdermal fentanyl (TDF) for pain management, but data on its efficacy and safety are scarce and inconsistent. This scoping review aims to analyze the evidence concerning TDF administration in patients with cachexia irrespective of the underlying pathology. The primary objective is to assess the analgesic efficacy and tolerability of TDF in cachectic patients. The secondary objective is to identify cachexia characteristics that may influence fentanyl pharmacokinetics (PK). A comprehensive search of PubMed, Embase, and Web of Science databases was conducted up to March 2024. The review included observational and clinical studies on cachectic patients with moderate to severe pain treated with TDF patches at any dosage or frequency. Phase 1 trials, animal studies, case reports, preclinical studies and conference abstracts were excluded. Nine studies were included: four studies reported that cachexia negatively impacted TDF efficacy, increasing required doses and lowering plasma concentrations; three studies found minimal or no impact of cachexia on TDF efficacy and PK; two studies suggested that cachexia might improve TDF outcomes. Study quality ranged from moderate to high, according to the National Institutes of Health (NIH) Quality Assessment Tool. The current evidence is insufficient to provide any definitive recommendations for TDF prescribing in cachectic patients.

Highly sensitive blood-based biomarkers detection of beta-amyloid and phosphorylated-tau181 for Alzheimer's disease.

Plasma biomarker has the potential to be the reliable and propagable approach in the early stage diagnosis of Alzheimer's disease (AD). However, conventional methods appear powerless in the detection of these biomarkers at low concentrations in plasma. Here, we determined plasma biomarker concentrations of patients across the AD spectrum by an improved digital enzyme-linked immunosorbent assay (ELISA) technique. Confirms the predictive and diagnostic value of this method for AD patients and study the relationships between these biomarkers and cognitive status. Plasma concentrations of amyloid-beta 40 (Aβ40), amyloid-beta 42 (Aβ42) and plasma phosphorylated tau at threonine 181 (p-tau181) were determined in 43 AD patients, 33 mild cognitive impairment (MCI) patients and 40 normal cognition (NC) subjects as healthy controls using the improved digital ELISA technique. In addition, all subjects were required to receive neuropsychological assessments. Plasma p-tau181 level showed certain discrepancies between NC and MCI (p < 0.05), AD (p < 0.01) groups. The level of plasma Aβ42 (p < 0.05) and Aβ40 (p < 0.01) was significantly different between AD and NC group. The p-tau181 level was able to distinguish AD (AUC = 0.8768) and MCI (AUC = 0.7932) from NC with higher accuracy than Aβ42/Aβ40 ratio (AUC = 0.8343, AUC = 0.6569). Both p-tau181 (CDR: r = 0.388 p < 0.001; MMSE: r = -0.394 p < 0.001) and Aβ42/Aβ40 ratio (CDR: r = -0.413 p < 0.001; MMSE: r = 0.358 p < 0.001) showed stronger positive correlation with clinical dementia rating (CDR) and mini mental state examination (MMSE) scores than Aβ42 (CDR: r = -0.280 p = 0.003; MMSE: r = 0.266 p = 0.005) or Aβ40 (CDR: r = 0.373 p < 0.001; MMSE: r = -0.288 p = 0.002) alone. Plasma p-tau181 level and Aβ42/Aβ40 ratio showed promising values in diagnosis of AD and MCI. Our results indicate that this improved digital ELISA diagnosis approach can facilitate early recognition and management of AD and pre-AD patients.

Patient resuscitated after cardiopulmonary arrest exhibits abnormally increased phenytoin metabolic rate due to unknown factors: a case report

BackgroundFosphenytoin (FOS) is a prodrug of phenytoin (PHT) with a metabolism that exhibits Michaelis–Menten-type kinetics. Genetic polymorphisms of the metabolic enzymes of PHT make it challenging to predict its plasma concentrations. High plasma PHT concentrations are typically problematic, and several causes have been elucidated. In contrast, cases of patients with low PHT plasma concentrations that did not increase despite the administration of appropriate PHT doses have been reported, and the causes may include changes in plasma protein-binding rates, genetic mutations, and concomitant use of drugs that induce liver enzymes; however, even these factors do not explain the low PHT plasma concentrations in some cases.Case presentationWe encountered the case of a patient with plasma PHT concentrations that were continuously < 0.7 µg/mL after daily use of FOS for seizures that occurred after cardiopulmonary arrest. We analyzed the protein-unbound fraction, urinary metabolites, and related genes to investigate the cause. False negatives due to the measurement method, errors in dosage and administration method, and increased excretion of PHT were excluded. Hepatic metabolic activity of PHT increased to 4.6–6.1 times the normal level. The S/R ratio of 5-(p-hydroxyphenyl)-5-phenylhydantoin-glucuronide, a major PHT metabolite, was normal at 15.2, suggesting increased activities of CYP2C9 and CYP2C19. Furthermore, the protein-unbound fraction of PHT was 5.2–6.9%, CYP2C19*17 was wild type, and there was no concomitant drug use to induce both enzymes.ConclusionsThe low PHT plasma concentration in this patient was found to be caused by increased hepatic metabolic activity that could not be explained by known factors. Careful monitoring is necessary to consider the possibility of increased hepatic metabolic activity in similar cases.