Therapeutic Concentrations Research Articles

Fentanyl Deaths in Infants and Children: A Case Series and Literature Review.

Death due to fentanyl and its various analogs has resulted in an exponential rise in deaths throughout the United States, overwhelming many medical examiner offices for over a decade. Its potency and prevalence have caused fentanyl to become the most reported substance in overdose fatalities, with an accompanying increase in exposure of the most vulnerable, infants and children. This report provides information about fentanyl in the pediatric population, including case examples, proposed investigative practices, published therapeutic and lethal blood concentrations, and available resources for future cases. Nine cases of pediatric death between 2013 and 2023 due to fentanyl were reviewed. Five case summaries are presented that highlight classic features of fentanyl deaths in infants, children, and teenagers. Deaths due to fentanyl have continued to rise year after year. Infants and children, most of whom are opioid naive, are at ever increased risk for exposure to high levels of fentanyl. The legal ramifications of a positive fentanyl level in a child increase the need for caution on the part of the forensic pathologist. Understanding what can and cannot be proven by autopsy as well as what resources are available to strengthen one's justification for fentanyl being the primary cause of death is critical.

Preclinical efficacy and pharmacokinetics of an RNA-encoded T cell-engaging bispecific antibody targeting human claudin 6.

We present the preclinical pharmacology of BNT142, a lipid nanoparticle (LNP)-formulated RNA (RNA-LNP) encoding a T cell-engaging bispecific antibody that monovalently binds the T cell marker CD3 and bivalently binds claudin 6 (CLDN6), an oncofetal antigen that is absent from normal adult tissue but expressed on various solid tumors. Upon BNT142 RNA-LNP delivery in cell culture, mice, and cynomolgus monkeys, RNA is translated, followed by self-assembly into and secretion of the functional bispecific antibody RiboMab02.1. In vitro, RiboMab02.1 mediated CLDN6 target cell-specific activation and proliferation of T cells, and potent target cell killing. In mice and cynomolgus monkeys, intravenously administered BNT142 RNA-LNP maintained therapeutic serum concentrations of the encoded antibody. Concentrations of RNA-encoded RiboMab02.1 were maintained longer in circulation in mice than concentrations of directly injected, sequence-identical protein. Weekly injections of mice with BNT142 RNA-LNP in the 0.1- to 1-μg dose range were sufficient to eliminate CLDN6-positive subcutaneous human xenograft tumors and increase survival over controls. Tumor regression was associated with an influx of T cells and depletion of CLDN6-positive cells. BNT142 induced only transient and low cytokine production in CLDN6-positive tumor-bearing mice humanized with peripheral blood mononuclear cells (PBMCs). No signs of adverse effects from BNT142 RNA-LNP administration were observed in mice or cynomolgus monkeys. On the basis of these and other findings, a phase 1/2 first-in-human clinical trial has been initiated to assess the safety and preliminary efficacy of BNT142 RNA-LNP in patients with CLDN6-positive advanced solid tumors (NCT05262530).

Calcineurin inhibitor effects on kidney electrolyte handling and blood pressure: tacrolimus versus voclosporin.

Calcineurin inhibitors affect kidney electrolyte handling and blood pressure through an effect on the distal tubule. The second generation calcineurin inhibitor voclosporin causes hypomagnesemia and hypercalciuria less often than tacrolimus. This suggests different effects on the distal tubule, but this has not yet been investigated experimentally. Rats were treated with voclosporin, tacrolimus or vehicle for 28 days. Dosing was based on a pilot experiment to achieve clinically therapeutic concentrations. Drug effects were assessed by electrolyte handling at day 18 and 28, thiazide testing at day 20, telemetric blood pressure recordings, and analysis of mRNA and protein levels of distal tubular transporters at day 28. Compared to vehicle, tacrolimus but not voclosporin significantly increased the fractional excretions of calcium (>4-fold), magnesium and chloride (both 1.5-fold) and caused hypomagnesemia. Tacrolimus but not voclosporin significantly reduced distal tubular transporters at mRNA and/or protein level, including the sodium-chloride cotransporter, transient receptor melastatin 6, transient receptor potential vanilloid 5, cyclin M2, sodium-calcium exchanger and calbindin-D28K. Tacrolimus but not voclosporin reduced the mRNA level and urinary excretion of epidermal growth factor. The saluretic response to hydrochlorothiazide at day 20 was similar in the voclosporin and vehicle groups, whereas it was lower in the tacrolimus group. The phosphorylated form of the sodium-chloride cotransporter was significantly higher at day 28 in rats treated with voclosporin than in those treated with tacrolimus. Tacrolimus transiently increased blood pressure, whereas voclosporin caused a gradual but persistent increase in blood pressure which was further characterized by high renin, normal aldosterone, and low endothelin-1. In contrast to tacrolimus, voclosporin does not cause hypercalciuria and hypomagnesemia, but similarly causes hypertension. Our data reveal differences between the distal tubular effects of tacrolimus and voclosporin and provide a pathophysiological basis for the clinically observed differences between the two calcineurin inhibitors.

N-acetylcysteine microparticles reduce cisplatin-induced RSC96 Schwann cell toxicity.

Cisplatin is known to cause inner ear dysfunction. There is growing evidence that cisplatin-induced demyelination of spiral or Scarpa's ganglion neurons may play an additional role in drug-induced ototoxicity alongside afferent neuron injury. As Schwann cells produce myelin, there may be an opportunity to reduce ototoxic inner ear damage by promoting Schwann cell viability. This work describes a cellular model of cisplatin-induced Schwann cell injury and investigates the ability of the antioxidant N-acetylcysteine to promote Schwann cell viability. A local delivery system of drug-eluting microparticles was then fabricated, characterized, and investigated for bioactivity. RSC96 rat Schwann cells were dosed with varying concentrations of cisplatin to obtain a dose curve and identify the lethal concentration of 50% of the cells (LC50). In subsequent experiments, RSC96 cells were co-treated with cisplatin and both resuspended or eluted N-acetylcysteine. Cell viability was assessed with the CCK8 assay. The LC50 dose of cisplatin was determined to be 3.76 μM (p = 2.2 x 10-16). When co-dosed with cisplatin and a therapeutic concentration of resuspended or eluted N-acetylcysteine, Schwann cells had an increased viability compared to cells dosed with cisplatin alone. RSC96 Schwann cell injury following cisplatin insult is characterized in this in vitro model. Cisplatin caused injury at physiologic concentrations and N-acetylcysteine improved cell viability and mitigated this injury. N-acetylcysteine was packaged into microparticles and eluted N-acetylcysteine retained its ability to increase cell viability, thus demonstrating promise as a therapeutic to offset cisplatin-induced ototoxicity. N/A Laryngoscope, 2023.

Evaluation of the Clinical Drug-Drug Interaction Potential of Pritelivir on Transporters and CYP450 Enzymes Using a Cocktail Approach.

Pritelivir is a novel viral helicase-primase inhibitor active against herpes simplex virus. In vitro drug-drug interaction studies indicated that pritelivir has the potential for clinically relevant interactions on the cytochrome P450 (CYP) enzymes 2C8, 2C9, 3A4, and 2B6, and intestinal uptake transporter organic anion transporting polypeptide (OATP) 2B1 and efflux transporter breast cancer resistance protein (BCRP). This was evaluated in 2 clinical trials. In 1 trial the substrates flurbiprofen (CYP2C9), bupropion (CYP2B6), and midazolam (CYP3A4) were administered simultaneously as part of the Geneva cocktail, while the substrate celiprolol (OAPT2B1) was administered separately. In another trial, the substrates repaglinide (CYP2C8) and rosuvastatin (BCRP) were administered separately. Exposure parameters of the substrates and their metabolites (flurbiprofen and bupropion only) were compared after administration with or without pritelivir under therapeutic concentrations. The results of these trials indicated that pritelivir has no clinically relevant effect on the exposure of substrates for the intestinal uptake transporter OATP2B1 and the CYP enzymes 3A4, 2B6, 2C9, and 2C8, and has a weak inhibitory effect on the intestinal efflux transporter BCRP. In summary, the results suggest that pritelivir has a low drug-drug interaction potential.

Strategies to Improve the Transdermal Delivery of Poorly Water-Soluble Non-Steroidal Anti-Inflammatory Drugs.

The transdermal delivery of non-steroidal anti-inflammatory drugs (NSAIDs) has the potential to overcome some of the major disadvantages relating to oral NSAID usage, such as gastrointestinal adverse events and compliance. However, the poor solubility of many of the newer NSAIDs creates challenges in incorporating the drugs into formulations suitable for application to skin and may limit transdermal permeation, particularly if the goal is therapeutic systemic drug concentrations. This review is an overview of the various strategies used to increase the solubility of poorly soluble NSAIDs and enhance their permeation through skin, such as the modification of the vehicle, the modification of or bypassing the barrier function of the skin, and using advanced nano-sized formulations. Furthermore, the simple yet highly versatile microemulsion system has been found to be a cost-effective and highly successful technology to deliver poorly water-soluble NSAIDs.

Exploring the antifungal, antibiofilm and antienzymatic potential of Rottlerin in an in vitro and in vivo approach

Candida species have been responsible for a high number of invasive infections worldwide. In this sense, Rottlerin has demonstrated a wide range of pharmacological activities. Therefore, this study aimed to evaluate the antifungal, antibiofilm and antivirulence activity of Rottlerin in vitro against Candida spp. and its toxicity and antifungal activity in vivo. Rottlerin showed antifungal activity against all yeasts evaluated, presenting Minimum Inhibitory and Fungicidal Concentration (MIC and MFC) values of 7.81 to > 1000 µg/mL. Futhermore, it was able to significantly inhibit biofilm production, presenting Biofilm Inhibitory Concentration (MICB50) values that ranged from 15.62 to 250 µg/mL and inhibition of the cell viability of the biofilm by 50% (IC50) from 2.24 to 12.76 µg/mL. There was a considerable reduction in all hydrolytic enzymes evaluated, with emphasis on hemolysin where Rottlerin showed a reduction of up to 20%. In the scanning electron microscopy (SEM) analysis, Rottlerin was able to completely inhibit filamentation by C. albicans. Regarding in vivo tests, Rottlerin did not demonstrate toxicity at the therapeutic concentrations demonstrated here and was able to increase the survival of C. elegans larvae infected. The results herein presented are innovative and pioneering in terms of Rottlerin’s multipotentiality against these fungal infections.

Nanoparticles for the treatment of spinal cord injury.

Spinal cord injuries lead to significant loss of motor, sensory, and autonomic functions, presenting major challenges in neural regeneration. Achieving effective therapeutic concentrations at injury sites has been a slow process, partly due to the difficulty of delivering drugs effectively. Nanoparticles, with their targeted delivery capabilities, biocompatibility, and enhanced bioavailability over conventional drugs, are garnering attention for spinal cord injury treatment. This review explores the current mechanisms and shortcomings of existing treatments, highlighting the benefits and progress of nanoparticle-based approaches. We detail nanoparticle delivery methods for spinal cord injury, including local and intravenous injections, oral delivery, and biomaterial-assisted implantation, alongside strategies such as drug loading and surface modification. The discussion extends to how nanoparticles aid in reducing oxidative stress, dampening inflammation, fostering neural regeneration, and promoting angiogenesis. We summarize the use of various types of nanoparticles for treating spinal cord injuries, including metallic, polymeric, protein-based, inorganic non-metallic, and lipid nanoparticles. We also discuss the challenges faced, such as biosafety, effectiveness in humans, precise dosage control, standardization of production and characterization, immune responses, and targeted delivery in vivo. Additionally, we explore future directions, such as improving biosafety, standardizing manufacturing and characterization processes, and advancing human trials. Nanoparticles have shown considerable progress in targeted delivery and enhancing treatment efficacy for spinal cord injuries, presenting significant potential for clinical use and drug development.

Pharmacokinetics and Safety of Intramuscular Injectable Benzathine Penicillin G in Japanese Healthy Participants.

An intramuscular (IM) suspension of benzathine penicillin G (BPG) has been used as first-line therapy for the treatment of syphilis worldwide since its approval in the 1950s. However, there are limited reports about the pharmacokinetics of BPG. A Phase 1 study was conducted on eight Japanese healthy participants to investigate the pharmacokinetics (samples collected predose to 648 h post-dose) and safety of 2.4 million units of BPG after a single IM injection. Following administration, penicillin G, the active moiety of BPG, was absorbed slowly from the injection site with a median time to Cmax (tmax) of 48 h post-dose. After the achievement of Cmax, concentrations of penicillin G declined slowly in a monophasic fashion with a mean apparent terminal half-life of 189 h. Geometric mean AUCinf and Cmax were 50770 ng•h/mL and 259 ng/mL, respectively. Median time (range) above the well-accepted therapeutic concentration (18 ng/mL) for syphilis treatment was 561 h (439-608 h [18-25 days]), which reached and exceeded the necessary duration of 7-10 days for syphilis treatment. Two participants were underdosed with residual drug left in the syringe due to the high viscosity of the drug product. Only one (12.5%) participant reported a mild adverse event of nasopharyngitis, which was considered not related to the study treatment. The study results supported BPG approval in Japan as an option for syphilis treatment.

Abstract PO2-05-05: ELECTRA: An open-label, multicenter, phase 1b/2 study of elacestrant in combination with abemaciclib in patients with brain metastasis (mets) from estrogen receptor-positive (ER+), HER2-negative (HER2-) breast cancer (BC)

Abstract Background: Currently, there are no approved systemic treatment options specifically for patients with ER+/HER2- BC who have brain metastasis. The prevalence of brain metastases from ER+/HER2- BC is approximately 14% of women (Aversa, 2014). Elacestrant is a next-generation oral SERD that was evaluated in a pivotal phase 3 trial, EMERALD, as monotherapy vs. standard of care (SOC) endocrine therapy. The EMERALD trial reported significantly prolonged progression-free survival (PFS) with elacestrant vs SOC endocrine therapy in patients with ER+/HER2− ESR1 mutated (ESR1-mut) mBC following progression on prior endocrine therapy (Bidard, 2022). Elacestrant was well tolerated with a manageable safety profile. Most adverse events, including nausea, were low-grade and consistent with other endocrine therapies. A clinical study in healthy postmenopausal women demonstrated the ability of elacestrant to cross the blood-brain barrier (Conlan, 2020). Abemaciclib, a CDK4/6i, has been shown to achieve therapeutic concentrations in brain metastases tissue (Tolaney, 2020). Given the lack of current systemic treatments, elacestrant is now being evaluated with abemaciclib in patients with ER+/HER2- BC and brain metastasis (NCT05386108). Methods: ELECTRA (NCT05386108) is an open-label phase 1b/2, multicenter study evaluating elacestrant in combination with abemaciclib in patients with brain metastasis from ER+, HER2- BC. Eligibility are patients with ER+/HER2− locally advanced or mBC and measurable brain metastasis. For phase 1b, the presence of brain metastases is allowed but not required for eligibility. For phase 2, patients must have ≥ 1 active and measurable brain metastasis per RECIST v1.1. Patients must have received prior therapy in the metastatic setting, including ≥ 1 ET, ≤2 chemotherapy regimens, and 0-2 prior CDK4/6i (excluding abemaciclib). The primary objectives of Phase 1b are to determine the recommended Phase 2 dose (RP2D). Phase 1b secondary objectives include safety, PK, objective response rate (ORR), duration of response (DoR), clinical benefit rate (CBR), PFS, and overall survival (OS). Phase 2 primary objective is ORR per RECIST version 1.1. Phase 2 secondary objectives include intracranial response rate (RR), DoR, CBR, PFS, OS, PK, and quality of life (QoL). The phase 1b portion evaluated dose-limiting toxicities (DLTs) of the combination during the first cycle (28 days) of treatment in up to three 6-patient cohorts, starting at elacestrant 300 mg daily plus abemaciclib 100 mg twice daily. Here we report initial safety results from the phase 1b portion. Results: As of June 2023, 15 patients have been enrolled in the phase 1b portion of the trial. At dose level 1, elacestrant 300 mg QD + abemaciclib 100 mg BID, no patient experienced DLTs, and the combination was feasible. Dose level 2, elacestrant 400 mg QD + abemaciclib 100 mg BID has been completed, and no patients experienced DLTs. In dose level 1, 4/7 patients remain on treatment at cycle 5. Additional safety and PK data for the cohorts will be provided. Conclusion: In the phase 1b portion of ELECTRA, dose level 1 and dose level 2 have been completed. No patients experienced DLTs in either dose level 1 or dose level 2, and the combination was considered feasible in the respective dose levels. Dose level 3 (elacestrant 400 mg QD + abemaciclib 150 mg BID) is proceeding. Recruitment is actively ongoing, enabling oral-oral combinations to determine a RP2D. Citation Format: Nuhad Ibrahim, Sung-Bae Kim, Nancy Lin, Ahmad Awada, Eva Ciruelos Gil, Giulia Tonini, Bartomeu Piza Vallespir, Kathy Puvana Theall, Erika Hamilton. ELECTRA: An open-label, multicenter, phase 1b/2 study of elacestrant in combination with abemaciclib in patients with brain metastasis (mets) from estrogen receptor-positive (ER+), HER2-negative (HER2-) breast cancer (BC) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-05-05.

Empagliflozin, an SGLT2i, relaxes coronary smooth muscle at pharmacological concentrations

Morbidity and mortality due to heart failure with preserved ejection fraction (HFpEF) is increasing and there are no universally recognized strategies for treatment. Sodium-glucose co-transporter type 2 inhibitors (SGLT2i), such as Empagliflozin, have been shown to reduce myocardial stiffness and improve coronary microvascular performance, but mechanisms are unclear. Previous studies in rabbit aorta and rat mesentery suggest Empagliflozin relaxes smooth muscle through activation of K+ channels. This study investigated the effects of therapeutic and pharmacological concentrations of Empagliflozin (10-300 μM) on the isometric tension of left circumflex (CFX) coronary arteries from Yorkshire swine. We tested the hypothesis that Empagliflozin would relax coronary smooth muscle via a concentration-dependent manner, involving K+ channels. CFX arteries were dissected, cleaned of adventitia, cut into 3 mm rings (n = 16), and mounted in organ baths containing Krebs-Henseleit buffer (37 °C) for isometric tension studies. Each CFX segment was adjusted to optimal preload (~3 g passive tension) as determined by <10 % change in active tension in response to 60 mM KCl. In order to determine whether Empagliflozin caused relaxation and, if so, by what mechanism, rings were contracted with either 30 mM K+ or the thromboxane mimetic U46619 (1 μM). Once tension plateaued, Empagliflozin (10-300 μM) was added in increasing concentrations. Therapeutic concentrations of Empagliflozin (10-30 μM), elicited no significant relaxation. Pharmacologic concentrations of Empagliflozin (≥100 μM) caused significant relaxation from ~15 ± 11% to ~45 ± 10% in response to 100 μM vs. 300 μM Empagliflozin, respectively. Relaxation was not different between rings contracted with K+ or U46619, suggesting membrane hyperpolarization via K+ channels is not involved. Our results represent the first study of the effects of Empagliflozin on coronary smooth muscle reactivity. Data support the idea that relaxation of coronary smooth muscle by Empagliflozin occurs at supra-pharmacologic concentrations in vitro, but K+ channel activation appears to be an unlikely mechanism. This project was supported by National Institutes of Health grant R01 HL158723. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Therapeutic effects of lincomycin and level of drug degradation in broiler tissues after treatment.

Lincomycin is an antibiotic used in broiler farming and is commonly combined with other substances to achieve synergistic and complementary effects on the antibacterial spectrum and mechanism. We developed a specific high-performance liquid chromatography (HPLC) method to measure lincomycin levels in broiler tissues. This study aimed to determine the lincomycin level in tissues and compare it with the minimum inhibitory concentration (MIC) and maximum residue limit (MRL) of certain pathogenic bacteria. Three groups of broiler chickens were involved in the study (n = 20 in each group): A control group without lincomycin treatment and two groups (each further divided into two sub-groups) that received oral lincomycin at a dose of 1 g/10 kg of body weight daily for 7 and 14 consecutive days. Tissue samples were collected from each group 1 day and 1 week after lincomycin administration (ALA). This study validated the development of a technique for analyzing drug level degradation in tissues using HPLC. Descriptive and statistical analyses were performed for drug levels to assess their therapeutic value and safety based on lincomycin MIC of certain pathogenic bacteria and MRL. The method validation resulted in linear regression and coefficient of determination for tissues with r2 > 0.99, with a recovery rate of 90%-110%, precision as the coefficient of variation 15%, and specificity with no peak overlap for lincomycin. The limits of detection for the liver and kidney were 0.01 μg/g, 0.05 μg/g, and 0.1 μg/g for the breast muscle and all tissues. Administration of lincomycin for 7 and 14 days resulted in therapeutic value concentrations. Lincomycin levels in the liver and kidney of ALA exceeded the MRL, whereas breast muscles were below the MRL for a week of ALA treatment. Administration of lincomycin for 7 and 14 consecutive days resulted in therapeutic value; however, after a week, most tissues showed high drug concentrations that exceeded the MRL. It is necessary to carefully consider the prolonged therapeutic dose of lincomycin in broilers. Antibiotic therapy must be guided in such a way as to protect the product from harmful residues.

Subcutaneous administration of ceftazidime at 20 and 40 mg/kg produces theoretically therapeutic plasma concentrations for at least 120 hours in red-eared sliders (Trachemys scripta elegans).

To evaluate and compare the pharmacokinetic parameters of SC ceftazidime administered at 20 and 40 mg/kg to red-eared sliders. 8 adult red-eared sliders (Trachemys scripta elegans). In a sequential, 2-period study with a 3-week washout period between treatments, ceftazidime was administered SC to turtles at 20 and 40 mg/kg. Blood samples were collected from the subcarapacial sinus at 0, 24, 48, 72, 96, and 120 hours after ceftazidime administration. Plasma ceftazidime concentrations were quantified using reversed-phase HPLC. Mean plasma half-life after 20- and 40-mg/kg dosing was 39.75 ± 8.0 hours and 33.03 ± 6.56 hours, respectively. Mean maximum plasma concentration after 20- and 40-mg/kg dosing was 71.0 ± 15.93 µg/mL and 120.0 ± 30.62 µg/mL, respectively. Mean plasma ceftazidime concentrations remained ≥ 8 µg/mL, the theoretical MIC for various reptile pathogens for all time points. Results indicate that ceftazidime dosed at either 20 or 40 mg/kg produces plasma concentrations exceeding the theoretical MIC of various reptile pathogens for at least 120 hours. An ideal dosing interval could not be determined, as all plasma concentrations remained above the threshold of interest for all time points. Follow-up studies should focus on establishing a dosing interval and more rigorous monitoring for potential adverse effects.

Pharmacokinetics, Fecal Output, and Grimace Scores in Rabbits Given Long-acting Buprenorphine or Fentanyl for Postsurgical Analgesia.

The New Zealand white rabbit (Oryctolagus cuniculus) is a frequently used surgical model. Pain management after surgery is a critical aspect of animal welfare. Recently, a long-acting buprenorphine formulation (Ethiqa XR; EXR) was approved for use in rats and mice but has not yet been investigated in rabbits. The current study aimed to determine whether a single subcutaneous dose of 0.15mg/kg of EXR could achieve and maintain therapeutic buprenorphine plasma concentrations (0.1ng/mL) for 72h in male and female rabbits. We also evaluated the safety profiles of EXR and the fentanyl patch (FP) by assessing fecal output after surgery, because opioids are known to decrease intestinal motility. Behavior and pain scores were compared for rabbits that received either EXR or the FP after undergoing an annulus puncture procedure to induce osteoarthritis. EXR at 0.15mg/kg SC provided a shorter time to onset and sustained analgesia for 72h in male and female rabbits, whereas the FP provided suboptimal analgesia after 48h. Both EXR and FP reduced fecal output after surgery. Output returned to baseline levels within 72h for the EXR group and remained slightly below baseline at 96h after surgery for the fentanyl group. Grimace pain scores revealed no significant difference between treatment groups. These results suggest that EXR is a safe and effective option for postoperative pain management in rabbits.

The Potential of the Fibronectin Inhibitor Arg-Gly-Asp-Ser in the Development of Therapies for Glioblastoma.

Glioblastoma (GBM) is the most lethal and common malignant primary brain tumor in adults. An important feature that supports GBM aggressiveness is the unique composition of its extracellular matrix (ECM). Particularly, fibronectin plays an important role in cancer cell adhesion, differentiation, proliferation, and chemoresistance. Thus, herein, a hydrogel with mechanical properties compatible with the brain and the ability to disrupt the dynamic and reciprocal interaction between fibronectin and tumor cells was produced. High-molecular-weight hyaluronic acid (HMW-HA) functionalized with the inhibitory fibronectin peptide Arg-Gly-Asp-Ser (RGDS) was used to produce the polymeric matrix. Liposomes encapsulating doxorubicin (DOX) were also included in the hydrogel to kill GBM cells. The resulting hydrogel containing liposomes with therapeutic DOX concentrations presented rheological properties like a healthy brain. In vitro assays demonstrated that unmodified HMW-HA hydrogels only caused GBM cell killing after DOX incorporation. Conversely, RGDS-functionalized hydrogels displayed per se cytotoxicity. As GBM cells produce several proteolytic enzymes capable of disrupting the peptide-HA bond, we selected MMP-2 to illustrate this phenomenon. Therefore, RGDS internalization can induce GBM cell apoptosis. Importantly, RGDS-functionalized hydrogel incorporating DOX efficiently damaged GBM cells without affecting astrocyte viability, proving its safety. Overall, the results demonstrate the potential of the RGDS-functionalized hydrogel to develop safe and effective GBM treatments.

Pharmacokinetics and Preclinical Safety Studies of Modified Endolysin-based Gel for Topical Application

Antibacterial therapy with phage-encoded endolysins or their modified derivatives with improved antibacterial, biochemical and pharmacokinetic properties is one of the most promising strategies that can supply existing antibacterial drugs array. Gram-negative bacteria-induced infections treatment is especially challenging because of rapidly spreading bacterial resistance. We have developed modified endolysin LysECD7-SMAP with a significant antibacterial activity and broad spectra of action against gram-negative bacteria. Endolysin was formulated in a bactericidal gel for topical application with pronounced effectivity in local animal infectious models. Here we present preclinical safety studies and pharmacokinetics of LysECD7-SMAP-based gel. We have detected LysECD7-SMAP in the skin and underlying muscle at therapeutic concentrations when the gel is applied topically to intact or injured skin. Moreover, the protein does not enter the bloodstream, and has no systemic bioavailability, assuming no systemic adverse effects. In studies of general toxicology, local tolerance, and immunotoxicology it was approved that LysECD7-SMAP gel local application results in the absence of toxic effects after single and multiple administration. Thus, LysECD7-SMAP-containing gel has appropriate pharmacokinetics and can be considered as safe that supports the initiation of the phase I clinical trials of novel antibacterial drug intending to treat acute wound infections caused by resistant gram-negative bacteria.

Higher Adalimumab Concentration Is Associated With Complete Fistula Healing in Patients With Perianal Fistulizing Crohn’s Disease

Perianal fistulas can develop in around 30% of patients with Crohn's disease (CD) and are associated with impaired quality of life and worse outcomes including increased rates of hospitalizations and surgeries.1 The cornerstone of pharmacologic treatment for perianal fistulizing CD is anti-tumor necrosis factor therapy, mainly infliximab and adalimumab (ADM).2 Therapeutic drug monitoring (TDM) can be used to identify potential pharmacokinetic and pharmacodynamic issues and avoid or manage unwanted outcomes, such as primary nonresponse and secondary loss of response.3 There are several exposure-response relationship data demonstrating a positive correlation between serum infliximab concentrations and favorable objective therapeutic outcomes in patients with perianal fistulizing CD.4 Nevertheless, there are only limited data, which is mostly from small retrospective studies regarding the association of ADM concentration and outcomes in patients with perianal fistulizing CD.4-8 Furthermore, the optimal ADM concentration for fistula healing still remains to be elucidated. This is clinically important because drug concentration cutoffs are used in reactive and proactive TDM algorithms to define therapeutic drug concentrations. This study investigates the association of maintenance ADM concentrations with complete fistula healing (CFH) and identifies an optimal ADM concentration threshold for CFH.

Impact Of Pharmacist Led Therapeutic Drug Monitoring of Vancomycin in Pediatric Cancer Patients

Aim This study aimed to evaluate the dosing regimen and therapeutic drug monitoring of vancomycin in this patient population. Method The study included 100 pediatric patients (3 months to 15 years) with various gram-positive bacterial infections. All patients received the initial vancomycin dose of 15 mg/kg every 6 hours. The researchers evaluated the incidence of achieving desired trough levels with this dosing regimen. Results The results revealed that patients between 1.0 and 5.9 years of age were less likely to achieve the desired trough levels with the initial vancomycin dose. Consequently, dose adjustments were made for patients with sub-therapeutic trough levels. These adjustments involved a 25% increase in the vancomycin dose. Importantly, the study found that the higher vancomycin dosing did not have any harmful effects on kidney function in pediatric patients, and no significant adverse effects were observed. Conclusion The dosing regimen of 15 mg/kg every 6 hours was unlikely to achieve the desired trough concentrations in pediatric patients with complicated infections and oncological diseases. The study recommends dose adjustments for the treatment of different infections in this population to increase the likelihood of reaching therapeutic steady-state concentrations of vancomycin.

Dried Blood Spots and Miniaturized Ultrasonic Nebulization Microplasma Optical Emission Spectrometry for Point-of-Care Testing of Blood Lithium.

Despite the significant importance of blood lithium (Li) detection in the treatment of bipolar disorder (BD), its point-of-care testing (POCT) remains a great challenge due to tedious sample preparation and the use of large-footprint atomic spectrometers. Herein, a system coupling dried blood spots (DBS) with a point discharge optical emission spectrometer equipped with a miniaturized ultrasonic nebulizer (MUN-μPD-OES) was developed for POCT of blood Li. Three microliters of whole blood were used to prepare a dried blood spot on a piece of filter paper to which 10 μL of eluent (1% (v/v) formic acid and 0.05% (v/v) Triton-X) was added. Subsequently, the paper was placed onto the vibrating steel membrane of the ultrasonic nebulizer and powered on to generate aerosol. The aerosol was directly introduced to the μPD-OES for quantification of Li by monitoring its atomic emission line at 670.8 nm. The proposed method minimized matrix interference caused by high levels of salts and protein. It is worth noting that the MUN suitably matches the needs of DBS sampling and can provide aerosolized introduction of Li into the assembled μPD-OES, thus eliminating all tedious sample preparation and the need for a commercial atomic spectrometer. Calibration response is linear in the therapeutic range and a limit of detection (LOD) of 1.3 μg L-1 is well below the Li minimum therapeutic concentration (2800 μg L-1). Li in mouse blood was successfully detected in real-time using MUN-μPD-OES after intraperitoneal injection of lithium carbonate, confirming that the system holds great potential for POCT of blood Li for patients with BD.

Influence of Genetic Polymorphisms in CYP3A5, CYP3A4, and MDR1 on Tacrolimus Metabolism after kidney transplantation

Kidney transplantation stands as the ultimate recourse for restoring vital organ functions, particularly in cases of end-stage kidney disease where alternative treatments, such as dialysis, prove less effective. With over 102,000 kidney transplants conducted globally in 2022, the demand for organ transplantation is ever-increasing, fueled by a rising incidence of end-stage renal disease attributed to causes like diabetes and hypertension.<br /> Despite significant advancements in kidney transplantation, immunosuppressive therapy remains crucial to preventing graft rejection. Tacrolimus (TAC), a calcineurin inhibitor, plays a pivotal role in this regard. Discovered in 1984, TAC inhibits T-lymphocyte activation, preventing acute rejection by disrupting the transcription of crucial genes involved in early T-cell activation. However, the use of TAC is not without challenges. The drug exhibits serious side effects, a narrow therapeutic index, and unpredictable pharmacokinetics. Therapeutic drug monitoring (TDM) becomes imperative in daily practice to maintain TAC blood concentrations within the therapeutic range. This literature review delves into the genetic aspects influencing TAC metabolism, focusing on key polymorphisms in CYP3A5, CYP3A4, and ABCB1 genes. Genetic variations in CYP3A5, a major enzyme in TAC metabolism, impact enzyme activity, necessitating personalized dosing strategies. CYP3A4 polymorphisms, especially CYP3A4*22, demonstrate associations with altered TAC clearance and dose requirements. The ABCB1 gene, encoding P-glycoprotein, another player in TAC pharmacokinetics, also exhibits polymorphisms influencing drug absorption and distribution. The ABCB1 3435C>T variant, in particular, shows potential implications on Tacrolimus bioavailability. Understanding these genetic variations aids in the development of personalized dosing regimens. Studies suggest that tailoring TAC doses based on CYP3A5 genotypes significantly improves the proportion of patients achieving therapeutic concentrations. Additionally, incorporating genetic information, particularly CYP3A4*22, into dosing strategies enhances the precision of TAC therapy, reducing the risk of adverse effects.