Effect of hypoalbuminemia on drug pharmacokinetics

Hypoalbuminemia, defined as serum albumin levels below 35 g/L, is common in patients with conditions such as nephrotic syndrome, cirrhosis, or sepsis. This review examines the impact of hypoalbuminemia on the pharmacokinetics of selected drugs-such as antibiotics, immunosuppressants, antifungals, or anticonvulsants-emphasizing its role in drug efficacy and safety. Albumin is the main drug transporter and key binding protein, which influences the free drug concentration and drug activity. The review includes all studies available in the scientific literature found in the PubMed, Scopus, and Cochrane databases. The paper emphasizes the importance of therapeutic drug monitoring (TDM) in patients with hypoalbuminemia to avoid subtherapeutic or toxic drug levels. Many drugs need for dose adjustments to achieve therapeutic levels, especially in critically ill patients. The results of studies emphasize the need for individualized dosing regimens based on TDM to optimize drug therapy in patients with hypoalbuminemia. Our review is the first article to summarize the influence of hypoalbuminemia on the pharmacokinetic parameters of drugs and may be a useful tool for clinicians in their daily work.

Quantitative prediction of drug disposition for uridine diphosphate-glucuronosyltransferase substrates using humanized mice

Drug clearance and drug-drug interactions are essential for pharmacokinetic assessment. However, current in vitro systems and animal scale-up approaches often fail to accurately predict drug disposition mediated by metabolizing enzymes, especially uridine diphosphate-glucuronosyltransferase (UGT). This study demonstrates how UGT-mediated drug disposition in humans can be predicted using hu-PXB mice (cDNA-uPA/severe combined immunodeficiency (SCID) mice transplanted with human-derived hepatocytes). To estimate human hepatic intrinsic clearance (CLh,int) in vitro, UGT substrates (acetaminophen, entacapone, ketoprofen, lorazepam, oxazepam, posaconazole, and zidovudine) were incubated with cryopreserved human hepatocytes. CLh,int was calculated based on the rate of substrate disappearance. In vivo human CLh,int values were calculated based on literature. To evaluate human CLh,int predictability, the 7 substrates were administered independently and intravenously to hu-PXB and SCID mice. We calculated the CLh,int in the mice and compared it with that in humans. For predicting UGT-mediated drug-drug interactions, 2 UGT substrates were administered intravenously to hu-PXB mice with or without probenecid (a UGT inhibitor). We compared the changes in clearance with those in humans. The in vitro assay using hepatocytes significantly underpredicted CLh,int in humans. Hu-PXB mice had a much better correlation with humans in CLh,int (R2 = 0.95) compared with SCID mice (R2 = 0.69). Hu-PXB mice predicted the CLh,int of UGT substrate drugs within 2-fold of the clinical values for every compound we evaluated. The decrease in clearance caused by probenecid in hu-PXB mice reflected that in humans. Our findings demonstrate that human drug disposition mediated by UGT can be predicted based on the in vivo studies using hu-PXB mice. SIGNIFICANCE STATEMENT: Human liver chimeric mice can accurately predict the clearance of uridine diphosphate-glucuronosyltransferase (UGT) substrate drugs and are likely to predict the magnitude of UGT-mediated drug-drug interactions. Findings from in vivo studies in humanized mice enable the selection of better candidates in drug discovery and allow for the more precise physiologically based pharmacokinetic modeling of UGT substrate drugs in clinical practice.

Therapeutic drug monitoring of azole antifungal agents

Deep-seated mycoses are generally opportunistic infections that are difficult to diagnose and treat. They are expected to increase with the spread of advanced medical care and aging populations, thus highlighting the need for safe, effective, and rapid drug-based treatments. Depending on a patient's age, sex, underlying diseases, and immune system status, therapeutic drug monitoring (TDM) may be important for assessing variable pharmacokinetic parameters, as well as preventing drug-drug interactions, adverse events, and breakthrough infections caused by fungal resistance. Azole antifungal agents play an important role in the prevention and treatment of deep-seated fungal infections, with each azoles having its own unique pharmacokinetic properties and specific adverse events. Therefore, it is necessary to use national and international guidelines to build evidence for the expansion of TDM indications. This review focuses on the clinical utility and future perspectives of TDM using azole antifungal agents, in the context of recent evidence in the literature.

Safety and efficacy of new generation azole antifungals in the management of recalcitrant superficial fungal infections and onychomycosis

INTRODUCTION

Terbinafine is considered the gold standard for treating skin fungal infections and onychomycosis. However, recent reports suggest that dermatophytes are developing resistance to terbinafine and the other traditional antifungal agents, itraconazole and fluconazole. When there is resistance to terbinafine, itraconazole or fluconazole, or when these agents cannot used, for example, due to potential drug interactions with the patient's current medications, clinicians may need to consider off-label use of new generation azoles, such as voriconazole, posaconazole, fosravuconazole, or oteseconazole. It is essential to emphasize that we do not advocate the use of newer generation azoles unless traditional agents such as terbinafine, itraconazole, or fluconazole have been thoroughly evaluated as first-line therapies.

AREAS COVERED

This article reviews the clinical evidence, safety, dosage regimens, pharmacokinetics, and management algorithm of new-generation azole antifungals.

EXPERT OPINION

Antifungal stewardship should be the top priority when prescribing new-generation azoles. First-line antifungal therapy is terbinafine and itraconazole. Fluconazole is a consideration but is generally less effective and its use may be off-label in many countries. For difficult-to-treat skin fungal infections and onychomycosis, that have failed terbinafine, itraconazole and fluconazole, we propose consideration of off-label voriconazole or posaconazole.

Clinical safety and efficacy of a single-dose gentamicin, posaconazole and mometasone furoate otic suspension for treatment of canine otitis externa

BACKGROUND

A single-dose, in-clinic, veterinary professional-administered treatment for canine otitis externa was developed to improve compliance and canine welfare.

METHODS

This multicentre, controlled, examiner-masked, randomised field trial was conducted in 316 dogs over 42 days. Dogs were treated once, on day 0, with the investigational product containing gentamicin, posaconazole and mometasone furoate (Mometamax Ultra [MU]) or twice (days 0 and 7) with a control product containing florfenicol, terbinafine and betamethasone acetate (CP). The primary endpoint was a composite otitis index score of 4 or less (of 12) on day 14 and 3 or less (of 12) on day 28.

RESULTS

On day 28, treatment success was recorded in 128 of 143 MU-treated dogs (89.5%), significantly non-inferior to 116 of 133 (87.2%) CP-treated dogs (Farrington-Manning test, Z = 4.1351, p < 0.0001). For mixed cultures of Staphylococcus pseudintermedius and Malassezia pachydermatis, there was 100% treatment success in MU-treated dogs (n = 33), significantly non-inferior to 90.2% (37 of 41) in CP-treated dogs (Farrington-Manning test, Z = 3.1954, p = 0.0007).

LIMITATIONS

Efficacy in chronic otitis externa cases was not investigated. Cytology was not used to aid in diagnosis or for identification of secondary pathogens.

CONCLUSION

This unique combination, single-dose product is safe and effective in dogs with otitis externa. It offers enhanced compliance, canine welfare and quality of life by eliminating the owner burden of treating this painful condition.

A Prospective Study to Evaluate the Effect of Therapeutic Drug Monitoring-Based Posaconazole Prophylaxis on Invasive Fungal Infection Rate During Acute Myeloid Leukemia Induction Therapy

Invasive fungal infections (IFIs) are a significant cause of morbidity and mortality in de-novo acute myeloid leukemia patients receiving induction chemotherapy. Despite using posaconazole, a broad-spectrum antifungal, for IFI prophylaxis, the breakthrough IFI rate is high in the real-world setting. One of the reasons could be frequent suboptimal plasma posaconazole levels. In the present study, we evaluated if therapeutic drug monitoring (TDM) guided posaconazole prophylaxis can reduce the IFI rates in comparison to a historical cohort. We enrolled 90 patients, > / = 16 years of age, without baseline IFIs, planned for remission induction therapy. All patients were started on posaconazole suspension 200 mg TDS and the dose was increased in a stepwise manner if trough levels were found to be suboptimal (< 350 ng/ml for day 2 or < 700 ng/ml subsequently). The TDM based approach resulted in a significant decline in breakthrough IFI rates (18% versus 52%, P < 0.0001) A total of 69 patients (78%) required dose escalation. Thirty-one patients required change in antifungals due to either suboptimal levels, persistent fever, diarrhoea or vomiting. We could not demonstrate an exposure-response relationship but the difference in IFI rates in patients with a median posaconazole level > / = 700 ng/ml (0%) and < 700 ng/ml (21.6%) was clinically meaningful. Posaconazole levels were found to be significantly lower in patients on antacids and prokinetics. The incidence of posaconazole-related grade 3 toxicity was low (2.3%). Thus TDM-based dosing of posaconazole helps reduce breakthrough IFI rate and should be a part of posaconazole prophylaxis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12288-023-01709-3.

Using molecularly dissolved drug concentrations in PBBMs improves the prediction of oral absorption from supersaturating formulations

Predicting the absorption of drugs from enabling formulations is still challenging due to the limited capabilities of standard physiologically based biopharmaceutics models (PBBMs) to capture complex absorption processes. Amongst others, it is often assumed that both, molecularly and apparently dissolved drug in the gastrointestinal lumen are prone to absorption. A recently introduced method for measuring concentrations of molecularly dissolved drug in a dynamic in vitro dissolution setup using microdialysis has opened new opportunities to test this hypothesis and refine mechanistic PBBM approaches. In the present study, we compared results of PBBMs that used either molecularly or apparently dissolved concentrations in the simulated gastrointestinal lumen as input parameters. The in vitro dissolution data from three supersaturating formulations of Posaconazole (PCZ) were used as model input. The modeling outcome was verified using PCZ concentration vs. time profiles measured in human intestinal aspirates and in the blood plasma. When using apparently dissolved drug concentrations (i.e., the sum of colloid-associated and molecularly dissolved drug) the simulated systemic plasma exposures were overpredicted, most pronouncedly with the ASD-based tablet. However, if the concentrations of molecularly dissolved drug were used as input values, the PBBM resulted in accurate prediction of systemic exposures for all three PCZ formulations. The present study impressively demonstrated the value of considering molecularly dissolved drug concentrations as input value for PBBMs of supersaturating drug formulations.

Enhanced antifungal activity of posaconazole against Candida auris by HIV protease inhibitors, atazanavir and saquinavir

The increasing incidence and dissemination of multidrug-resistant Candida auris represents a serious global threat. The emergence of pan-resistant C. auris exhibiting resistance to all three classes of antifungals magnifies the need for novel therapeutic interventions. We identified that two HIV protease inhibitors, atazanavir and saquinavir, in combination with posaconazole exhibited potent activity against C. auris in vitro and in vivo. Both atazanavir and saquinavir exhibited a remarkable synergistic activity with posaconazole against all tested C. auris isolates and other medically important Candida species. In a time-kill assay, both drugs restored the fungistatic activity of posaconazole, resulting in reduction of 5 and 5.6 log10, respectively. Furthermore, in contrast to the individual drugs, the two combinations effectively inhibited the biofilm formation of C. auris by 66.2 and 81.2%, respectively. Finally, the efficacy of the two combinations were tested in a mouse model of C. auris infection. The atazanavir/posaconazole and saquinavir/posaconazole combinations significantly reduced the C. auris burden in mice kidneys by 2.04- (99.1%) and 1.44-log10 (96.4%) colony forming unit, respectively. Altogether, these results suggest that the combination of posaconazole with the HIV protease inhibitors warrants further investigation as a new therapeutic regimen for the treatment of C. auris infections.

Human Data on Pharmacokinetic Interactions of Cannabinoids: A Narrative Review

Concomitant use of cannabinoids with other drugs may result in pharmacokinetic drug-drug interactions, mainly due to the mechanism involving Phase I and Phase II enzymes and/or efflux transporters. Cannabinoids are not only substrates but also inhibitors or inducers of some of these enzymes and/or transporters. This narrative review aims to provide the available information reported in the literature regarding human data on the pharmacokinetic interactions of cannabinoids with other medications. A search on Pubmed/Medline, Google Scholar, and Cochrane Library was performed. Some studies were identified with Google search. Additional articles of interest were obtained through cross-referencing of published literature. All original research papers discussing interactions between cannabinoids, used for medical or recreational/adult-use purposes, and other medications in humans were included. Thirty-two studies with medicinal or recreational/adult-use cannabis were identified (seventeen case reports/series, thirteen clinical trials, and two retrospective analyses). In three of these studies, a bidirectional pharmacokinetic drug-drug interaction was reported. In the rest of the studies, cannabinoids were the perpetrators, as in most of them, concentrations of cannabinoids were not measured. In light of the widespread use of prescribed and non-prescribed cannabinoids with other medications, pharmacokinetic interactions are likely to occur. Physicians should be aware of these potential interactions and closely monitor drug levels and/or responses. The existing literature regarding pharmacokinetic interactions is limited, and for some drugs, studies have relatively small cohorts or are only case reports. Therefore, there is a need for high-quality pharmacological studies on cannabinoid-drug interactions.

Posaconazole exposure in critically ill ICU patients: a need for action

PURPOSE

Posaconazole is an antifungal drug currently being used for prophylaxis and treatment of invasive fungal infections such as aspergillosis. To date, therapeutic drug monitoring (TDM) of posaconazole is recommended with the use of oral suspension, but the potential need of TDM with the use of IV formulations is rising. Therefore, we aimed to investigate the pharmacokinetics of IV posaconazole in critically ill patients.

METHODS

In a prospective study, we analysed 168 consecutivelly collected posaconazole levels from 10 critically ill patients drawn during a 7 day curse. Posaconazole concentrations were measured using a chromatographic method. Demographic and laboratory data were collected, and the data was analysed using descriptive statistics.

RESULTS

We included 168 posaconazole levels, resulting in a median trough of 0.62 [0.29-1.05] mg/L with 58% not reaching the suggested target of 0.5 mg/L for fungal prophylaxis. Moreover, 74% of the trough levels were under the target of 1 mg/L which is proposed for the treatment of aspergillosis.

CONCLUSION

Posaconazole exposure is highly variable in critically ill patients resulting in potentially insufficient drug concentrations in many cases. TDM is highly recommended to identify and avoid underexposure.

TRIAL REGISTRATION NUMBER

NCT05275179, March 11, 2022.

Successful Treatment of Paecilomyces variotii Pneumonia and Lupus Nephritis With Posaconazole-Cyclophosphamide Co-administration Without Drug Interaction-Induced Toxicity

Paecilomyces variotii is an opportunistic mold that causes pulmonary infections in immunosuppressed humans that are often treated with triazole therapy. Lupus nephritis is a major cause of progressive kidney disease in patients with systemic lupus erythematosus, often requiring cyclophosphamide-based therapies. Triazole-cyclophosphamide co-administration is challenging as triazoles increase cyclophosphamide concentrations, which can worsen cyclophosphamide toxicity. We describe herein a patient with Paecilomyces variotii pneumonia and concomitant lupus nephritis who was successfully treated with posaconazole and echinocandin-bridged interruptions to allow for cyclophosphamide therapy. This regimen was well-tolerated without cyclophosphamide toxicity and achieved improvements in both fungal pneumonia and renal function.

Voriconazole Pharmacokinetics in Critically Ill Patients and Extracorporeal Membrane Oxygenation Support: A Retrospective Comparative Case-Control Study

Voriconazole, an antifungal agent, displays high intra- and inter-individual variability. The predictive pharmacokinetic (PK) index requires a minimum plasma concentration (C_min) in patient serum of between 1-5.5 mg/L. It is common to encounter fungal infections in patients undergoing extracorporeal membrane oxygenation (ECMO) support, and data regarding voriconazole PK changes during ECMO are scarce. Our study compared voriconazole PKs in patients with and without ECMO support in a retrospective cohort of critically-ill patients. Fifteen patients with 26 voriconazole C_min determinations in the non-ECMO group and nine patients with 27 voriconazole C_min determinations in the ECMO group were recruited. The ECMO group had lower C_min (0.38 ± 2.98 vs. 3.62 ± 3.88, p < 0.001) and higher infratherapeutic C_min values (16 vs. 1, p < 0.001) than the non-ECMO group. Multivariate analysis identified ECMO support (-0.668, CI₉₅ -0.978--0.358) and plasma albumin levels (-0.023, CI₉₅ -0.046--0.001) as risk factors for low C_min values. When comparing pre- and post-therapeutic drug optimisation samples from the ECMO group, the dose required to achieve therapeutic C_min was 6.44 mg/kg twice a day. Therapeutic drug optimisation is essential to improve target attainment.

Drug-drug interactions that alter the exposure of glucuronidated drugs: Scope, UDP-glucuronosyltransferase (UGT) enzyme selectivity, mechanisms (inhibition and induction), and clinical significance

Drug-drug interactions (DDIs) arising from the perturbation of drug metabolising enzyme activities represent both a clinical problem and a potential economic loss for the pharmaceutical industry. DDIs involving glucuronidated drugs have historically attracted little attention and there is a perception that interactions are of minor clinical relevance. This review critically examines the scope and aetiology of DDIs that result in altered exposure of glucuronidated drugs. Interaction mechanisms, namely inhibition and induction of UDP-glucuronosyltransferase (UGT) enzymes and the potential interplay with drug transporters, are reviewed in detail, as is the clinical significance of known DDIs. Altered victim drug exposure arising from modulation of UGT enzyme activities is relatively common and, notably, the incidence and importance of UGT induction as a DDI mechanism is greater than generally believed. Numerous DDIs are clinically relevant, resulting in either loss of efficacy or an increased risk of adverse effects, necessitating dose individualisation. Several generalisations relating to the likelihood of DDIs can be drawn from the known substrate and inhibitor selectivities of UGT enzymes, highlighting the importance of comprehensive reaction phenotyping studies at an early stage of drug development. Further, rigorous assessment of the DDI liability of new chemical entities that undergo glucuronidation to a significant extent has been recommended recently by regulatory guidance. Although evidence-based approaches exist for the in vitro characterisation of UGT enzyme inhibition and induction, the availability of drugs considered appropriate for use as 'probe' substrates in clinical DDI studies is limited and this should be research priority.

Antifungals: From Pharmacokinetics to Clinical Practice

The use of antifungal drugs started in the 1950s with polyenes nystatin, natamycin and amphotericin B-deoxycholate (AmB). Until the present day, AmB has been considered to be a hallmark in the treatment of invasive systemic fungal infections. Nevertheless, the success and the use of AmB were associated with severe adverse effects which stimulated the development of new antifungal drugs such as azoles, pyrimidine antimetabolite, mitotic inhibitors, allylamines and echinochandins. However, all of these drugs presented one or more limitations associated with adverse reactions, administration route and more recently the development of resistance. To worsen this scenario, there has been an increase in fungal infections, especially in invasive systemic fungal infections that are particularly difficult to diagnose and treat. In 2022, the World Health Organization (WHO) published the first fungal priority pathogens list, alerting people to the increased incidence of invasive systemic fungal infections and to the associated risk of mortality/morbidity. The report also emphasized the need to rationally use existing drugs and develop new drugs. In this review, we performed an overview of the history of antifungals and their classification, mechanism of action, pharmacokinetic/pharmacodynamic (PK/PD) characteristics and clinical applications. In parallel, we also addressed the contribution of fungi biology and genetics to the development of resistance to antifungal drugs. Considering that drug effectiveness also depends on the mammalian host, we provide an overview on the roles of therapeutic drug monitoring and pharmacogenomics as means to improve the outcome, prevent/reduce antifungal toxicity and prevent the emergence of antifungal resistance. Finally, we present the new antifungals and their main characteristics.

Salvage Treatment for Invasive Aspergillosis and Mucormycosis: Challenges, Recommendations and Future Considerations

Invasive mold diseases are devastating systemic infections which demand meticulous care in selection, dosing, and therapy monitoring of antifungal drugs. Various circumstances regarding PK/PD properties of the applied drug, resistance/tolerance of the causative pathogen or host intolerability can lead to failure of the initial antifungal therapy. This necessitates treatment adaption in the sense of switching antifungal drug class or potentially adding another drug for a combination therapy approach. In the current state of drastically limited options of antifungal drug classes adaption of therapy remains challenging. Current guidelines provide restricted recommendations only and emphasize individual approaches. However, novel antifungals, incorporating innovative mechanisms of action, show promising results in late stage clinical development. These will expand options for salvage therapy in the future potentially as monotherapy or in combination with conventional or other novel antifungals. We outline current recommendations for salvage therapy including PK/PD considerations as well as elucidate possible future treatment options for invasive aspergillosis and mucormycosis.

In Vitro Susceptibilities of Worldwide Isolates of Intrapulmonary Aspergillus Species and Important Candida Species in Sterile Body Sites against Important Antifungals: Data from the Antimicrobial Testing Leadership and Surveillance Program, 2017-2020

To understand the changes of resistance in clinically commonly encountered fungi, we used the Antimicrobial Testing Leadership and Surveillance (ATLAS) database to explore in vitro antifungal susceptibilities against clinically important isolates of Aspergillus and Candida species (collected from intrapulmonary and sterile body areas, respectively). We applied the CLSI antifungal 2020 and the EUCAST antifungal 2020 guidelines. From 2017 to 2020, isolates of intrapulmonary Aspergillus fumigatus (n = 660), Aspergillus niger (n = 107), Aspergillus flavus (n = 96), Aspergillus terreus (n = 40), and Aspergillus nidulans species complex (n = 26) and sterile site-originated isolates of Candida albicans (n = 1,810), Candida glabrata (n = 894), Candida krusei (n = 120), Candida dubliniensis (n = 107), Candida lusitaniae (n = 82), Candida guilliermondii (n = 28), and Candida auris (n = 7) were enrolled in this study. Using the EUCAST 2020 breakpoints, it was demonstrated that amphotericin B and posaconazole displayed poor in vitro susceptibility rates against A. fumigatus isolates (<50% and 18.9%, respectively). In contrast, isavuconazole and itraconazole showed high in vitro potency against most Aspergillus isolates (>92%). Most intrapulmonary Aspergillus isolates exhibited MICs of ≤0.06 μg/mL to anidulafungin. Furthermore, intrapulmonary A. fumigatus isolates collected from Italy and the United Kingdom exhibited lower in vitro susceptibility to isavuconazole (72.2% and 69%, respectively) than those in the remaining ATLAS participant countries (>85%). Higher isavuconazole MIC90s against C. auris and C. guilliermondii (1 and 4 μg/mL, respectively) were observed compared to the other five Candida species. Despite the aforementioned MICs and susceptibilities against fungi, research needs to consider the pharmacokinetic (PK) profiles, pharmacodynamic (PD) parameters, and clinical treatment experience with antifungals against specific Aspergillus species. IMPORTANCE In addition to monitoring the antifungal susceptibilities of clinically important fungi, reviewing the PK/PD indices and the clinical therapy experience of antifungals under evaluation are important to guide an appropriate antifungal prescription. The efficacies of liposomal amphotericin B complex and anidulafungin for the treatment of pulmonary aspergillosis caused by different Aspergillus species need to be periodically evaluated in the future.

Gellan gum-based in situ gelling ophthalmic nanosuspension of Posaconazole

The formulation and delivery of highly hydrophobic drugs in an optimized dosage form is challenging to formulation scientists. Posaconazole has shown promising action in case studies against fungal keratitis. Biological macromolecules like gellan gum would aid in enhancing the availability of such drugs by increasing the contact time of the formulation. Herein, we propose a transmucosal ocular delivery system of Posaconazole by developing a gellan gum-based in situ gelling nanosuspension. The HPLC method for Posaconazole was developed and validated as per ICH guidelines. The nanosuspension was prepared by microfluidization and optimized by Quality by Design. The gellan gum concentration selected was 0.4% w/v based on the viscosity and mucoadhesion measurements. A greater zone of inhibition of ~ 15 mm was observed for the prepared nanosuspension as compared to ~ 11 mm for the marketed itraconazole nanosuspension. A potential irritancy score of 0.85, considered to be non-irritant, was observed for the developed nanosuspension. Higher drug release of ~ 35% was noted for the nanosuspension compared to about ~ 10% for the coarse suspension. Ex vivo corneal retention studies on excised goat cornea demonstrated ~ 70% drug retention in the tissue. Graphical abstract depicting the central hypothesis of the work.

A Review of Population Pharmacokinetic Models of Posaconazole

Posaconazole is often used for the prophylaxis and treatment of invasive fungal infections (IFI). However, intra- and inter-individual differences and drug interactions affect the efficacy and safety of posaconazole. Precision dosing of posaconazole based on the population pharmacokinetic (PopPK) model may assist in making significant clinical decisions. This review aimed to comprehensively summarize the published PopPK models of posaconazole and analyze covariates that significantly influence posaconazole exposure. Articles published until May 2022 for PopPK analysis of posaconazole were searched in PubMed and EMBASE databases. Demographic characteristics, model characteristics, and results of PopPK analysis were extracted from the selected articles. In addition, the steady-state pharmacokinetic profiles of posaconazole were simulated at different covariate levels and dosing regimens. Out of the 13 studies included in our review, nine studies included adults, three included children, and one included both adults and children. All oral administration models were one-compartment models, and all intravenous administration models were two-compartment models. Body weight, proton pump inhibitors, and incidence of diarrhea were found to be important covariates. Clinically, the potential impact of factors such as patient physiopathologic characteristics and comorbid medications on posaconazole pharmacokinetics should be considered. Dose adjustment in combination with TDM or replacement with a tablet or intravenous formulation with higher exposure may be an effective way to ensure drug efficacy as well as to reduce fungal resistance. Meanwhile, published models require further external evaluation to examine extrapolation.

Factors associated with subtherapeutic levels of oral posaconazole tablet- a detailed analysis from a tertiary care center in India

INTRODUCTION

Posaconazole is a broad spectrum triazole antifungal with activity against various clinically important fungi. The delayed release (DR) tablet of posaconazole has been shown to have a superior pharmacokinetic profile in comparison with the oral suspension.

METHODS

We retrospectively analyzed the factors associated with posaconazole levels < 1.25 μg/ml in 164 patients receiving the DR tablet for therapeutic purposes.

RESULTS

Of the 164 patients, 53 (32.3%) showed subtherapeutic trough levels of posaconazole. The use of proton pump inhibitors (PPIs) (95% CI: 1.41 - 3.91; p value = 0.028) and the presence of diarrhea (95% CI: 1.95 - 6.93; p value = 0.001) were significantly associated with subtherapeutic levels. Thirteen of the 21 patients receiving posaconazole tablets via the nasogastric (NG) tube had therapeutic levels.

CONCLUSION

This is the largest study from India analyzing factors associated with subtherapeutic levels of the DR tablet of posaconazole. These findings reinforce the importance of therapeutic drug monitoring. Unlike in previous studies, obesity and hypoalbuminemia were not found to be significant factors in our settings. The use of PPIs and diarrhea remained significant factors as found in previous studies. Administering the DR tablet of posaconazole via the NG tube may be a viable option.

Phase 1b/3 Pharmacokinetics and Safety Study of Intravenous Posaconazole in Adult Asian Participants at High Risk for Invasive Fungal Infections

Introduction

Antifungal prophylaxis in patients at high risk for invasive fungal infections (IFIs), such as those with acute myeloid leukemia or myelodysplastic syndromes, continues to be underused in Asia, despite the fact that it reduces IFI-related death and increases IFI-free survival. We characterized the pharmacokinetics (PK) and safety of the intravenous (IV) formulation of posaconazole in adult Asian participants at high risk for IFI.

Methods

Participants received posaconazole IV 300 mg twice on day 1, posaconazole IV 300 mg once daily on days 2–10, and posaconazole IV 300 mg once daily or oral suspension 200 mg 3 times daily for up to 18 days for a maximum of 28 days. There were two PK sampling groups: intensive and sparse. Sparse trough PK sampling was collected from all participants on days 3, 6, 10, 15, 22, and 28/end of treatment. The intensive PK group had additional sampling performed over 24 h on day 10. Primary end points were steady state average concentration (C_avg,ss) and percentage of participants with C_avg,ss ≥ 500 ng/mL. Safety was assessed up to day 30/end of treatment.

Results

Seventy participants with acute myelogenous leukemia were enrolled, 30 in the intensive PK group and 40 in the sparse PK group; 57 participants completed the study, 26 in the intensive PK group and 31 in the sparse PK group. On day 10, arithmetic mean C_avg,ss was 2986 ng/mL [coefficient of variation (%CV), 36%; range, 1409–5930 ng/mL]; 100% of participants in the intensive PK group (n/N = 27/27) had C_avg,ss ≥ 500 ng/mL. Arithmetic mean (%CV) C_min was 2474 (50.4%) and 2466 ng/mL (42.4%) in the intensive and sparse PK groups on day 10, respectively. Safety was similar to that of previous posaconazole formulations.

Conclusion

In Asian participants at high risk for IFIs, IV posaconazole achieved the target exposure associated with efficacy that was previously established for supporting global registration of posaconazole for IV administration and was generally well tolerated.

Clinical trial registration

ClinicalTrials.gov, NCT03336502.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-02012-1.

Dental and Oral Manifestations of COVID-19 Related Mucormycosis: Diagnoses, Management Strategies and Outcomes

It has been nearly two years since the pandemic caused by the novel coronavirus disease (COVID-19) has affected the world. Several innovations and discoveries related to COVID-19 are surfacing every day and new problems associated with the COVID-19 virus are also coming to light. A similar situation is with the emergence of deep invasive fungal infections associated with severe acute respiratory syndrome 2 (SARS-CoV-2). Recent literature reported the cases of pulmonary and rhino-cerebral fungal infections appearing in patients previously infected by COVID-19. Histopathological analysis of these cases has shown that most of such infections are diagnosed as mucormycosis or aspergillosis. Rhino-orbital-cerebral mucormycosis usually affects the maxillary sinus with involvement of maxillary teeth, orbits, and ethmoidal sinuses. Diabetes mellitus is an independent risk factor for both COVID-19 as well as mucormycosis. At this point, there is scanty data on the subject and most of the published literature comprises of either case reports or case series with no long-term data available. The aim of this review paper is to present the characteristics of COVID-19 related mucormycosis and associated clinical features, outcome, diagnostic and management strategies. A prompt diagnosis and aggressive treatment planning can surely benefit these patients.

The Overview on the Pharmacokinetic and Pharmacodynamic Interactions of Triazoles

Second generation triazoles are widely used as first-line drugs for the treatment of invasive fungal infections, including aspergillosis and candidiasis. This class, along with itraconazole, voriconazole, posaconazole, and isavuconazole, is characterized by a broad range of activity, however, individual drugs vary considerably in safety, tolerability, pharmacokinetics profiles, and interactions with concomitant medications. The interaction may be encountered on the absorption, distribution, metabolism, and elimination (ADME) step. All triazoles as inhibitors or substrates of CYP isoenzymes can often interact with many drugs, which may result in the change of the activity of the drug and cause serious side effects. Drugs of this class should be used with caution with other agents, and an understanding of their pharmacokinetic profile, safety, and drug-drug interaction profiles is important to provide effective antifungal therapy. The manuscript reviews significant drug interactions of azoles with other medications, as well as with food. The PubMed and Google Scholar bases were searched to collect the literature data. The interactions with anticonvulsants, antibiotics, statins, kinase inhibitors, proton pump inhibitors, non-nucleoside reverse transcriptase inhibitors, opioid analgesics, benzodiazepines, cardiac glycosides, nonsteroidal anti-inflammatory drugs, immunosuppressants, antipsychotics, corticosteroids, biguanides, and anticoagulants are presented. We also paid attention to possible interactions with drugs during experimental therapies for the treatment of COVID-19.

Evaluating posaconazole, its pharmacology, efficacy and safety for the prophylaxis and treatment of fungal infections

INTRODUCTION

Invasive fungal diseases (IFDs) are a significant cause of morbidity and mortality among immunocompromised patients. Safe and effective antifungal medications used for prophylaxis and treatment are pivotal in their management. Posaconazole is a promising triazole antifungal agent.

AREAS COVERED

The authors discuss the pharmacological properties of posaconazole, including pharmacokinetics/pharmacodynamics, safety and tolerability profile, together with efficacy data for prophylaxis and treatment as well as its use in special populations based on current literature.

EXPERT OPINION

Posaconazole has a favorable safety and tolerability profile; however, caution is advised when co-administered with agents that are CYP3A4 inhibitors, because their concentration may significantly increase, and their levels should be closely monitored. It has an extended spectrum of activity against yeasts and filamentous fungi. It is successfully used as prophylaxis for patients with acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) and post-hematopoietic cell transplantation (HCT) with graft-versus-host disease (GVHD). It is the first line treatment for oropharyngeal candidiasis and is also used as a salvage treatment for refractory IFDs. Currently available formulations include the oral suspension, delayed-release tablets and solution for intravenous infusion, all with different PK/PD properties and indications. Its use in children and adolescents is currently being examined in Phase-II clinical trials.

In Vitro-In Vivo Correlation in Cocrystal Dissolution: Consideration of Drug Release Profiles Based on Coformer Dissolution and Absorption Behavior

This study assessed the in vitro-in vivo correlation in cocrystal dissolution based on the coformer behavior. 4-Aminobenzoic acid (4ABA) was used as a coformer. Cocrystals of poorly water-soluble drugs with 4ABA, ketoconazole cocrystal (KTZ-4ABA), posaconazole cocrystal (PSZ-4ABA), and itraconazole cocrystal (ITZ-4ABA) were used. These three cocrystals generated supersaturated solutions in fasted state simulated intestinal fluid (FaSSIF) in a small-scale, 8 mL dissolution vessel. The time profile of the dissolved amount of 4ABA, an indicator of cocrystal dissolution, was significantly different among the three cocrystals. Under the conditions utilized, half of the KTZ-4ABA cocrystal solid rapidly dissolved within 5 min and the dissolved amount (% of applied amount) of KTZ and 4ABA was the same. Then, even though the residual solid cocrystal gradually dissolved, KTZ precipitated with time. The PSZ-4ABA cocrystal dissolved in a linear fashion with time but the dissolved concentration of PSZ reached a plateau in the supersaturated state and was maintained for at least 2 h. The dissolution rate of ITZ-4ABA was very slow compared to those of the other cocrystals, but a similar tendency was observed between cocrystal dissolution and the dissolved amount of ITZ. The rank order of the cocrystal dissolution rate based on the conformer concentration was KTZ-4ABA > PSZ-4ABA > ITZ-4ABA. Furthermore, cocrystallization of the three drugs with 4ABA significantly enhanced the oral drug absorption in rats. The rank order of the in vivo cocrystal dissolution rate by a deconvolution analysis with the plasma concentration-time profile of 4ABA was KTZ-4ABA > PSZ-4ABA > ITZ-4ABA, which corresponded well with the in vitro dissolution profiles of the cocrystals. These results indicate that analysis of cocrystal dissolution based on the coformer behavior may be useful to evaluate the in vitro and in vivo cocrystal dissolution.

Posaconazole treatment of refractory coccidioidomycosis in dogs

Background

The majority of dogs with coccidioidomycosis recover with administration of fluconazole or itraconazole, although some cases are refractory or the dogs do not tolerate administration of these medications.

Objectives

The objective was to describe the treatment outcomes and therapeutic monitoring of 8 dogs with refractory coccidioidomycosis treated with posaconazole.

Animals

Eight dogs with refractory coccidioidomycosis.

Methods

Retrospective case series. Medical records from Veterinary Specialty Center of Tucson were searched to identify dogs with refractory coccidioidomycosis that were treated with posaconazole. Clinical information and the results of monitoring trough serum posaconazole concentrations were retrieved.

Results

Eight dogs with refractory coccidioidomycosis were treated with 2.5 to 10 mg/kg per day of posaconazole. Six of 8 dogs recovered or developed clinical remission while administered posaconazole. Thirteen serum concentrations from 8 dogs tested were >1 μg/mL (range, 1.52 to >6 μg/mL) and the drug was well‐tolerated by 7 dogs. One dog required dosage reductions and treatment was ultimately discontinued because of hepatotoxicosis.

Conclusions and Clinical Importance

Posaconazole should be considered as a treatment option for dogs with refractory coccidioidomycosis. Monitoring of indicators of liver function or injury along with therapeutic drug monitoring is recommended to tailor dosage in the event of hepatic toxicosis.

Voriconazole‐Associated Periostitis: New Insights into Pathophysiology and Management

Voriconazole‐associated periostitis (VAP) is an underrecognized and unpredictable side effect of long‐term voriconazole therapy. We report two cases of VAP occurring in the post‐transplant setting: a 68‐year‐old lung transplant recipient who required ongoing voriconazole therapy, in whom urinary alkalinization was used to promote fluoride excretion and minimize voriconazole‐related skeletal toxicity, and a 68‐year‐old stem‐cell transplant recipient with a high voriconazole dose requirement, identified on pharmacogenomic testing to be a CYP2C19 ultrarapid metabolizer, the dominant enzyme in voriconazole metabolism. This is the first reported case of pharmacogenomic profiling in VAP and may explain the variability in individual susceptibility to this uncommon adverse effect. Our findings provide new insights into both the management and underlying pathophysiology of VAP. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A Population Pharmacokinetic Modeling and Simulation Study of Posaconazole Oral Suspension in Immunocompromised Pediatric Patients: A Short Communication

BACKGROUND

Posaconazole oral suspension emerged as a promising candidate for prophylaxis of invasive fungal infections in immunocompromised children. Its pharmacodynamic advantages include a broad-spectrum activity and a favorable safety profile; however, they are overshadowed by its large pharmacokinetic (PK) variability, which might cause subtherapeutic exposure. The aim of this study was to develop a population (pop) PK model based on rich sampling data to better understand the PK of posaconazole oral suspension in pediatric patients.

METHODS

Data were obtained from a prospective interventional study involving hospitalized pediatric patients with a hematologic malignancy and prophylactically treated with posaconazole oral suspension. After constructing the popPK model, the probability of target attainment (PTA; 100% T ≥ 0.7 mg/L) for prophylaxis under fixed, body weight-based, and body surface area-based dosing was evaluated using Monte Carlo simulation.

RESULTS

Fourteen patients contributed 112 posaconazole plasma concentrations. The PK of posaconazole was adequately described by a 1-compartment model with lag time 2.71 hours [13%]; nonlinear bioavailability ED50 99.1 mg/m2 (fixed); first-order absorption rate constant 0.325 hour-1 [27%]; apparent volume of distribution 1150 L [34%]; and apparent clearance 15.4 L/h [24%] (∼70-kg individual). The bioavailability decreased in the presence of diarrhea and co-treatment with a proton pump inhibitor (PPI). The unexplained interindividual variability in posaconazole PK remained large. The PTA was <85%, irrespective of the simulated dosing strategy. Patients without diarrhea and not administered a PPI had the highest PTA (85% under the fixed 300-mg dosing 4 times per day).

CONCLUSIONS

Therapeutic drug monitoring is recommended during prophylactic posaconazole therapy in immunocompromised pediatric patients. Large-scale comparative studies are needed to characterize the PK variability between different posaconazole formulations in this cohort.

In vitro activity of posaconazole and comparators versus opportunistic filamentous fungal pathogens globally collected during 8 years

The epidemiology of invasive filamentous fungal diseases requires monitoring due to changes in susceptibility patterns of new and established antifungal agents that may affect clinical practices. We evaluated the activity of posaconazole against 2,157 invasive moulds collected worldwide from 2010-2017. The isolates included 1,775 Aspergillus spp. and 382 non-Aspergillus moulds, including 81 Fusarium spp., 62 Mucorales group, and 57 Scedosporium spp. Isolates were tested using the CLSI reference broth microdilution method. Posaconazole showed similar activity to itraconazole and voriconazole against A. fumigatus. Applying published ECV, 98.0% of the A. fumigatus and 97.7% to 100.0% of other common Aspergillus species were wildtype to posaconazole. Categorical agreement between posaconazole and the other azoles tested against A. fumigatus was 98.7%. Notably, most of the Aspergillus spp. isolates recovered from this large collection were wildtype to echinocandins and all azoles. Posaconazole non-wildtype rates of A. fumigatus varied across the different geographic regions, with 2.1% in Europe, 2.2% in North America, 1.8% in Latin America, and 0.7% in the Asia-Pacific region. The frequency of azole non-wildtype A. fumigatus isolates from Europe increased steadily from 2010-2017 for all 3 triazoles (0.0%-5.0%). The azole non-wildtype A. fumigatus rates from the other geographic areas were stable over time. Fusarium and/or Scedosporium spp. isolates were highly resistant to azoles and echinocandins. Posaconazole and amphotericin B were the most active agents against the Mucorales. Posaconazole was very active against most species of Aspergillus and was comparable to itraconazole and voriconazole against the less common moulds. Posaconazole should provide a useful addition to the anti-mould grouping of antifungal agents.

Unintentional artenimol/piperaquine overdose in two children occurring without evidence of subsequent cardiotoxicity

At the emergency department of the Robert-Debré children's hospital in Paris, France, artenimol/piperaquine (AP) has been the first-line antimalarial treatment since September 2012. Most children receive the first dose at the hospital and return home if, after 1 hour's observation, there have been no episodes of vomiting. Here we report the case of two children, aged 11 years and 5 years, respectively, in whom the entire cumulative 3 days' treatment course combined was accidentally administered instead of just the first-day treatment dose. Serum piperaquine levels were measured between Hour 40 (H40) and Day 29 (D29) post-ingestion for the first patient, and between H17 and D7 for the second patient. Corrected QT (QTc) values were measured between H12 and D20 for the first patient and between H17 and H64 for the second patient. Despite reports of adverse electrophysiological events, AP overdose occurred without consequence on the QTc interval or clinical cardiac state in these two children.

CF Fungal Disease in the Age of CFTR Modulators

Fungi are increasingly recognised to have a significant role in the progression of lung disease in Cystic fibrosis with Aspergillus fumigatus the most common fungus isolated during respiratory sampling. The emergence of novel CFTR modulators has, however, significantly changed the outlook of disease progression in CF. In this review we discuss what impact novel CFTR modulators will have on fungal lung disease and its management in CF. We discuss how CFTR modulators affect antifungal innate immunity and consider the impact of Ivacaftor on fungal disease in individuals with gating mutations. We further review the increasing complication of drug-drug interactions with concurrent use of azole antifungal medication and highlight key unknowns that require addressing to fully understand the impact of CFTR modulators on fungal disease.

Antifungal therapy with azoles and the syndrome of acquired mineralocorticoid excess

The syndromes of mineralocorticoid excess describe a heterogeneous group of clinical manifestations leading to endocrine hypertension, typically either through direct activation of mineralocorticoid receptors or indirectly by impaired pre-receptor enzymatic regulation or through disturbed renal sodium homeostasis. The phenotypes of these disorders can be caused by inherited gene variants and somatic mutations or may be acquired upon exposures to exogenous substances. Regarding the latter, the symptoms of an acquired mineralocorticoid excess have been reported during treatment with azole antifungal drugs. The current review describes the occurrence of mineralocorticoid excess particularly during the therapy with posaconazole and itraconazole, addresses the underlying mechanisms as well as inter- and intra-individual differences, and proposes a therapeutic drug monitoring strategy for these two azole antifungals. Moreover, other therapeutically used azole antifungals and ongoing efforts to avoid adverse mineralocorticoid effects of azole compounds are shortly discussed.

Novel Application of Pentabromobenzyl Column for Simultaneous Determination of Eight Antifungal Drugs Using High-performance Liquid Chromatography

Aim:

A new, accurate and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) as an analytical method for the quantitative determination of eight antifungal drugs in spiked human plasma has been described optimized and validated.

Methods and Materials:

The analyzed compounds were voriconazole (VOR), luliconazole (LUL), clotrimazole (CLO), tioconazole (TIO), posaconazole (POS), ketoconazole (KET), sertaconazole (SER) and terconazole (TER).

Results:

The separation of the analyzed compounds was conducted using a novel pentabromobenzyl column known as COSMOSIL PBB-R (150 mm × 4.6 mm I.D., particle size 5 μm). The analysis of the studied drugs was determined within 14 min using a diode array detector and the mobile phase consisted of: 10 mM potassium dihydrogen phosphate buffer (pH 2.1): Methanol (2: 98 v/v). A linear response was observed for all compounds in the range of concentration studied. Sample preparation was done through liquid-liquid extraction using diethyl ether.

Conclusion:

This proposed method was validated in terms of linearity, limit of quantification, limit of detection, accuracy, precision and selectivity. The method was successfully applied for the determination of these drugs in their pharmaceutical formulations and in human plasma samples.

Posaconazole aggravates vincristine-related hypertension in children with acute lymphoblastic leukemia: a case report

Vincristine-related secondary hypertension is rare. This study reports two children who were treated with vincristine for acute lymphoblastic leukemia (ALL) and posaconazole for fungal infections who experienced vincristine-related secondary hypertension. Blood pressure normalized in both children after halting the drugs and providing antihypertensive treatment. Thus, posaconazole can interact with vincristine and induce secondary hypertension in children with ALL. As an adverse event, this interaction is a rare occurrence.

Current Approaches to Drug Discovery for Chagas Disease: Methodological Advances

BACKGROUND

In recent years, there has been an improvement in the in vitro and in vivo methodology for the screening of anti-chagasic compounds. Millions of compounds can now have their activity evaluated (in large compound libraries) by means of high throughput in vitro screening assays.

OBJECTIVE

Current approaches to drug discovery for Chagas disease.

METHOD

This review article examines the contribution of these methodological advances in medicinal chemistry in the last four years, focusing on Trypanosoma cruzi infection, obtained from the PubMed, Web of Science, and Scopus databases.

RESULTS

Here, we have shown that the promise is increasing each year for more lead compounds for the development of a new drug against Chagas disease.

CONCLUSION

There is increased optimism among those working with the objective to find new drug candidates for optimal treatments against Chagas disease.

PBPK modeling of CYP3A and P-gp substrates to predict drug-drug interactions in patients undergoing Roux-en-Y gastric bypass surgery

Roux-en-Y gastric bypass surgery (RYGBS) is an effective surgical intervention to reduce mortality in morbidly obese patients. Following RYGBS, the disposition of drugs may be affected by anatomical alterations and changes in intestinal and hepatic drug metabolizing enzyme activity. The aim of this study was to better understand the drug-drug interaction (DDI) potential of CYP3A and P-gp inhibitors. The impacts of RYGBS on the absorption and metabolism of midazolam, acetaminophen, digoxin, and their major metabolites were simulated using physiologically-based pharmacokinetic (PBPK) modeling. PBPK models for verapamil and posaconazole were built to evaluate CYP3A- and P-gp-mediated DDIs pre- and post-RYGBS. The simulations suggest that for highly soluble drugs, such as verapamil, the predicted bioavailability was comparable pre- and post-RYGBS. For verapamil inhibition, RYGBS did not affect the fold-change of the predicted inhibited-to-control plasma AUC ratio or predicted inhibited-to-control peak plasma concentration ratio for either midazolam or digoxin. In contrast, the predicted bioavailability of posaconazole, a poorly soluble drug, decreased from 12% pre-RYGBS to 5% post-RYGBS. Compared to control, the predicted posaconazole-inhibited midazolam plasma AUC increased by 2.0-fold pre-RYGBS, but only increased by 1.6-fold post-RYGBS. A similar trend was predicted for pre- and post-RYGBS inhibited-to-control midazolam peak plasma concentration ratios (2.0- and 1.6-fold, respectively) following posaconazole inhibition. Absorption of highly soluble drugs was more rapid post-RYGBS, resulting in higher predicted midazolam peak plasma concentrations, which was further increased following inhibition by verapamil or posaconazole. To reduce the risk of a drug-drug interaction in patients post-RYGBS, the dose or frequency of object drugs may need to be decreased when administered with highly soluble inhibitor drugs, especially if toxicities are associated with plasma peak concentrations.

Small-Molecule Inhibitors Targeting Sterol 14α-Demethylase (CYP51): Synthesis, Molecular Modelling and Evaluation Against Candida albicans

Fungal infections are a global issue affecting over 150 million people worldwide annually, with 750 000 of these caused by invasive Candida infections. Azole drugs are the frontline treatment against fungal infections; however, resistance to current azole antifungals in C. albicans poses a threat to public health. Two series of novel azole derivatives, short and extended derivatives, have been designed, synthesised and investigated for CYP51 inhibitory activity, binding affinity and minimum inhibitory concentration (MIC) against C. albicans strains. The short derivatives were more potent against the C. albicans strains (e. g., MIC 2-(4-chlorophenyl)-N-(2,4-dichlorobenzyl)-3-(1H-imidazol-1-yl)propanamide (5 f) <0.03 μg/mL, N-(4-((4-chlorophenyl)sulfonamido)benzyl)-2-phenyl-3-(1H-1,2,4-triazol-1-yl)propanamide (12 c), 1 μg/mL, fluconazole 0.125 μg/mL) but both displayed comparable enzyme binding and inhibition (5 f Kd 62±17 nM, IC50 0.46 μM; 12 c Kd 43±18 nM, IC50 0.33 μM, fluconazole Kd 41±13 nM, IC50 0.31 μM, posaconazole Kd 43±11 nM, IC50 0.2 μM). The short series had poor selectivity for CaCYP51 over the human homologue, whereas the selectivity of the extended series, for example, compound 12 c, was higher (21.5-fold) than posaconazole (4.7-fold) based on Kd values, although posaconazole was more selective (615-fold) than 12 c (461-fold) based on IC50 values. Based on inhibitory activity and selectivity profile, the extended series are the better of the two series for further development.

Rhizoferrin Glycosylation in Rhizopus microsporus

Rhizopus spp. are the most common etiological agents of mucormycosis, causing over 90% mortality in disseminated infections. The diagnosis relies on histopathology, culture, and/or polymerase chain reaction. For the first time, the glycosylation of rhizoferrin (RHF) was described in a Rhizopus microsporus clinical isolate by liquid chromatography and accurate tandem mass spectrometry. The fermentation broth lyophilizate contained 345.3 ± 13.5, 1.2 ± 0.03, and 0.03 ± 0.002 mg/g of RHF, imido-RHF, and bis-imido-RHF, respectively. Despite a considerable RHF secretion rate, we did not obtain conclusive RHF detection from a patient with disseminated mucormycosis caused by the same R. microsporus strain. We hypothesize that parallel antimycotic therapy, RHF biotransformation, and metabolism compromised the analysis. On the other hand, the full profile of posaconazole metabolites was retrieved by our in house software CycloBranch.

Optimization and Characterization of Aqueous Micellar Formulations for Ocular Delivery of an Antifungal Drug, Posaconazole

Background:

Topical therapy is preferred for the management of ocular fungal infections due to its superiorities which include overcoming potential systemic side effects risk of drugs, and targeting of drugs to the site of disease. However, the optimization of effective ocular formulations has always been a major challenge due to restrictions of ocular barriers and physiological conditions. Posaconazole, an antifungal and highly lipophilic agent with broad-spectrum, has been used topically as off-label in the treatment of ocular fungal infections due to its highly lipophilic character. Micellar carriers have the potential to improve the solubility of lipophilic drugs and, overcome ocular barriers.

Objective:

In the current study, it was aimed optimization of posaconazole loaded micellar formulations to improve aqueous solubility of posaconazole and to characterize the formulations and to investigate the physical stability of these formulations at room temperature (25°C, 60% RH), and accelerated stability (40°C, 75% RH) conditions.

Method:

Micelles were prepared using a thin-film hydration method. Pre-formulation studies were firstly performed to optimize polymer/surfactant type and to determine their concentration in the formulations. Then, particle size, size distribution, and zeta potential of the micellar formulations were measured by ZetaSizer Nano-ZS. The drug encapsulation efficiency of the micelles was quantified by HPLC. The morphology of the micelles was depicted by AFM. The stability of optimized micelles was evaluated in terms of particle size, size distribution, zeta potential, drug amount and pH for 180 days. In vitro release studies were performed using Franz diffusion cells.

Results:

Pre-formulation studies indicated that single D-ɑ-tocopheryl polyethylene glycol succinate (TPGS), a combination of it and Pluronic F127/Pluronic F68 are capable of formation of posaconazole loaded micelles at specific concentrations. Optimized micelles with high encapsulation efficiency were less than 20 nm, approximately neutral, stable, and in aspherical shape. Additionally, in vitro release data showed that the release of posaconazole from the micelles was higher than that of suspension.

Conclusion:

The results revealed that the optimized micellar formulation of posaconazole offers a potential approach for topical ocular administration.

Pharmacokinetics and Safety of Posaconazole Tablet Formulation in Chinese Participants at High Risk for Invasive Fungal Infection

INTRODUCTION

This study characterized the multidose pharmacokinetic (PK) characteristics of posaconazole tablets used as prophylactic antifungal therapy in Chinese patients with acute myelogenous leukemia (AML) at risk for invasive fungal infection (IFI).

METHODS

Participants in this open-label, single-arm, phase 1b study received posaconazole 300 mg twice daily on day 1 and then once daily for up to 28 days. In the intensive PK sampling subgroup, posaconazole was administered under fasting conditions on days 1 and 8, and blood samples were regularly collected over 24 h. Trough PK sampling was conducted in all participants on days 1, 2, 3, 8, 14, 21, and 28 without regard for food intake. Population PK characteristics were predicted using PK modeling. Primary endpoints were steady-state average concentration (C_avg) and percentage of participants with steady-state C_avg (predicted and observed) > 500 ng/ml. Treatment safety and efficacy were secondary endpoints.

RESULTS

Sixty-five adult Chinese participants were enrolled. On day 8, steady-state arithmetic mean C_avg was 1610 ng/ml (% coefficient of variation [%CV] 42.8%) in the intensive PK subgroup (n = 20). All participants achieved a steady-state C_avg > 500 ng/ml. Predicted C_avg (pC_avg) was 1770 ng/ml (%CV 33.7%) in the total population (n = 64); 92.2% of participants had pC_avg values ≥ 500 ng/ml (n = 59). The posaconazole tablet safety profile was consistent with that of the oral formulation, and the IFI rate was 3%.

CONCLUSION

In Chinese AML patients, the posaconazole 300-mg tablet provided PK data comparable with those of previous studies and was generally well tolerated and efficacious.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02387983.

Rhizopus Infection in a Preterm Infant: A Novel Use of Posaconazole

Posaconazole is a triazole antifungal with activity against Rhizopus, but data on its use and pharmacokinetics in preterm infants are scarce. In this case, a 24 4/7-week neonate's Rhizopus infection is successfully treated with debridement and combination antifungal therapy with amphotericin B, micafungin and enteral posaconazole. This is the first reported posaconazole use in a preterm neonate with Rhizopus.

Antifungal Drugs

We reviewed the licensed antifungal drugs and summarized their mechanisms of action, pharmacological profiles, and susceptibility to specific fungi. Approved antimycotics inhibit 1,3-β-d-glucan synthase, lanosterol 14-α-demethylase, protein, and deoxyribonucleic acid biosynthesis, or sequestrate ergosterol. Their most severe side effects are hepatotoxicity, nephrotoxicity, and myelotoxicity. Whereas triazoles exhibit the most significant drug–drug interactions, echinocandins exhibit almost none. The antifungal resistance may be developed across most pathogens and includes drug target overexpression, efflux pump activation, and amino acid substitution. The experimental antifungal drugs in clinical trials are also reviewed. Siderophores in the Trojan horse approach or the application of siderophore biosynthesis enzyme inhibitors represent the most promising emerging antifungal therapies.

Intravenous and Oral Posaconazole Pharmacokinetics in a Five-Year-Old With Mucor: A Case Report and Review of the Literature

Posaconazole is a lipophilic triazole antifungal that exhibits variable absorption when administered orally. It possesses a broad spectrum of activity against various fungi, such as Aspergillus and traditionally resistant molds such as Rhizopus and Mucor, which carry a poor prognosis. Unfortunately, the tablet and suspension formulations of posaconazole are Food and Drug Administration approved for treatment of fungal diseases only in patients older than 13 years of age. Furthermore, the approval of the IV formulation is exclusively for adult patients. Nevertheless, the extended spectrum of activity and available dosage forms make it an attractive option for pediatric use. The data that exist to guide dosing of posaconazole in young pediatric patients are limited primarily to case series and case reports. Thus, we recommend therapeutic drug monitoring to ensure both safety and efficacy in pediatric patients. Herein we describe our experience with both oral and IV posaconazole in the salvage therapy of a 5-year-old female with extensive cutaneous Mucor. In contrast to previous reports, which show larger doses may be necessary to obtain therapeutic concentrations in pediatric patients as compared with adults, our patient reached targeted concentrations with weight-based dosing.

Pharmacokinetics and Safety of Posaconazole Administered by Intravenous Solution and Oral Tablet in Healthy Chinese Subjects and Effect of Food on Tablet Bioavailability

BACKGROUND AND OBJECTIVES

New intravenous and solid oral formulations of the antifungal agent posaconazole have been developed. This randomized, open-label, crossover study in 18 healthy adult Chinese male and female subjects evaluated the pharmacokinetics of single-dose posaconazole (oral 300-mg posaconazole tablet fasted, intravenous 300-mg posaconazole solution fasted, and oral 300-mg posaconazole tablet with standard high-fat breakfast). Primary objectives were to determine the single-dose pharmacokinetics of posaconazole in healthy Chinese subjects when administered as an intravenous solution and as an oral tablet under fasted conditions and the effect of food on the absorption of posaconazole.

METHODS

The three treatments consisted of the following: a single oral dose of posaconazole 300 mg (fasted), a single oral dose of posaconazole 300 mg (high-fat breakfast), and a single intravenous dose of posaconazole 300 mg (fasted). Blood samples for pharmacokinetic analysis were collected before dosing and at regular intervals after dosing. Adverse events were monitored throughout. The pharmacokinetic population included the per-protocol population. The safety population included all subjects who received one or more doses of the study drug.

RESULTS

Time to maximum plasma concentration of intravenous posaconazole coincided with the end of infusion; the half-life (t½) was 25.76 h. Geometric mean (% coefficient of variation) values of area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUC_0-∞) and maximum plasma concentration (C_max) were 59,925 (36.2%) h·ng/mL and 3999 (28.5%) ng/mL, respectively. The posaconazole tablet had a time to maximum plasma concentration of 4 h and a t½ of 25.21 h after fasting. Geometric mean (coefficient of variation) values of AUC_0-∞ and C_max were 25,263 (39.9%) h·ng/mL and 674.5 (29.6%) ng/mL, respectively. Standard high-fat breakfast increased the exposure of posaconazole approximately twofold with geometric mean ratios (high-fat breakfast/fasted) for AUC_0-∞ and C_max of 2.06 (90% confidence interval 1.86-2.30) and 1.95 (90% confidence interval 1.65-2.31), respectively. The geometric mean absolute bioavailability of the tablet formulation was 42.2% in the fasted state and 87.1% under high-fat breakfast conditions. The most commonly reported adverse events were nausea, vomiting, dizziness, and first-degree atrioventricular block for intravenous posaconazole 300 mg and nausea for oral posaconazole 300 mg (high-fat breakfast). All adverse events were mild and resolved without sequelae.

CONCLUSIONS

Posaconazole was generally well tolerated in healthy Chinese male and female subjects. The safety and the high-fat breakfast and fasted pharmacokinetics of posaconazole in healthy Chinese subjects are within exposures demonstrated to be generally well tolerated and efficacious and compare reasonably well with the overall posaconazole data across Western countries.

Posaconazole-Induced Hypertension Due to Inhibition of 11β-Hydroxylase and 11β-Hydroxysteroid Dehydrogenase 2

We describe two cases of hypertension and hypokalemia due to mineralocorticoid excess caused by posaconazole treatment of coccidioidomycosis and rhinocerebral mucormycosis infections, respectively. Clinical laboratory evaluations, including a comprehensive analysis of blood and urine steroid profiles, revealed low renin and aldosterone and indicated as the underlying mechanism primarily a block of 11β-hydroxylase activity in patient 1, whereas patient 2 displayed weaker 11β-hydroxylase but more pronounced 11β-hydroxysteroid dehydrogenase 2 inhibition. The results show that both previously suggested mechanisms must be considered and emphasize significant interindividual differences in the contribution of each enzyme to the observed mineralocorticoid excess phenotype. The mineralocorticoid symptoms of patient 1 resolved after replacement of posaconazole therapy by isavoconazole, and posaconazole dosage de-escalation ameliorated the effects in patient 2. By providing a thorough analysis of the patients’ blood and urine steroid metabolites, this report adds further evidence for two individually pronounced mechanisms of posaconazole-induced hypertension and hypokalemia. The elucidation of the factors responsible for the individual phenotype warrants further research.

A case report of disseminated histoplasmosis and concurrent cryptococcal meningitis in a patient treated with ruxolitinib

Background

Ruxolitinib is a highly potent janus kinase inhibitor that places its users at risk for various bacterial infections and viral reactivation. However new reports are also emerging that suggest greater immunosuppression and risk for fungal disease.

Case presentation

We report the case of a 51 year-old veteran from Guam, treated with ruxolitinib for polycythemia vera, who developed disseminated histoplasmosis and concurrent cryptococcal meningitis.

Conclusion

This case draws attention to the degree of immunosuppression that may be seen with this drug and the need for heightened vigilance for opportunistic infections in those treated with inhibitors of janus kinase/signal transducers and activators of transcription (JAK/STAT) such as ruxolitinib.

Single-Dose Pharmacokinetic Properties and Relative Bioavailability of Different Formulations of Posaconazole Oral Suspension in Healthy Volunteers

The rate and extent of absorption of drugs belonging to Biopharmaceutics Classification System class II are rate-limited by dissolution and highly dependent on the performance of the formulated product. The purpose of the present study was to investigate the potential impact of a surfactant and the particle size of the active substance on the in vitro drug dissolution profiles and in vivo pharmacokinetics of the poorly soluble drug posaconazole. A comparative physicochemical evaluation was conducted, and 3 formulations of posaconazole oral suspension were tested in various dissolution media compared with the reference product. In addition, a comparative bioavailability study was conducted in healthy volunteers under high-fat fed conditions. Bioequivalence was assessed based on plasma concentrations of the parent drug (posaconazole) measured by a validated high-pressure liquid chromatography-tandem mass spectrometry method. The 90% confidence intervals for C_max and AUC_0-72 least-squares mean T/R ratios of all 3 posaconazole formulations were within the bioequivalence acceptance range of 80.00% to 125.00%. The study was useful in the formulation development process and demonstrated that neither surfactant type nor particle size of the active substance within the studied range affected the extent or rate of absorption of posaconazole under the tested fed conditions.