Efficacy, Biodistribution, and Nephrotoxicity of Experimental Amphotericin B-Deoxycholate Formulations for Pulmonary Aspergillosis

Tigecycline Absorption Improved by Selected Excipients

To investigate the effects of (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD), (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD), tocopherol polyethylene glycol 1000 succinate (TPGS), sodium desoxycholate (SDOCH), trimethyl chitosan (TMC), and sodium caprate (C10) on the plasma concentration and the oral bioavailability of tigecycline in broiler chickens. To test the effects of the excipients on absorption of tigecycline, a tetracycline that is poorly absorbed from the gastrointestinal tract, broiler chickens were used as an animal model. Tigecycline (10 mg/kg body weight) was administered intravenously, orally, and orally with one of the excipients. Plasma samples were taken after administration. To measure tigecycline concentrations, high-performance liquid chromatography coupled with tandem mass spectrometry was used. Compartmental and non-compartmental analyses were used for pharmacokinetic analyses of mean plasma concentrations versus time. With the exception of sodium caprate, all the excipients significantly increased the area under the curve and bioavailability of tigecycline (p < 0.05). These parameters were approximately doubled by HP-β-CD, TPGS, and SDOCH, with 95% confidence intervals (95% CIs) for the difference that included only increases of 1.5-fold or higher (bioavailability: control, 1.67%; HP-β-CD, 3.24%; TPGS, 3.30%; and SDOCH, 3.24%). The increases in these parameters were smaller with DM-β-CD and TMC (DM-β-CD, 2.41%; TMC, 2.55%), and the 95% CIs ranged from close to no difference to nearly double the values in the control group. These results indicate that HP-β-CD, TPGS, and SDOCH substantially increase the area under the curve and oral bioavailability of tigecycline. They suggest that DM-β-CD and TMC may also substantially increase these parameters, but more research is needed for more precise estimates of their effects.

Trends in the Prevalence of Amphotericin B-Resistance (AmBR) among Clinical Isolates of Aspergillus Species

The challenges of the invasive infections caused by the resistant Aspergillus species include the limited access to antifungals for treatment and high mortality. This study aimed to provide a global perspective of the prevalence of amphotericin B resistance (AmBR), geographic distribution, and the trend of AmBR from 2010 to 2020. To analyze the prevalence of in vitro AmBR in clinical Aspergillus species, we reviewed the literature and identified a total of 72 articles. AmBR was observed in 1128 out of 3061 Aspergillus terreus (36.8%), 538 out of 3663 Aspergillus flavus (14.9%), 141 out of 2691 Aspergillus niger (5.2%), and 353 out of 17,494 Aspergillus fumigatus isolates (2.01%). An increasing trend in AmB-resistant isolates of A. fumigatus and a decreasing trend in AmB-resistant A. terreus and A. flavus isolates were observed between 2016 and 2020. AmB-resistant A. terreus and A. niger isolates, accounting for 40.4% and 20.9%, respectively, were the common AmB-resistant Aspergillus species in Asian studies. However, common AmB-resistant Aspergillus species reported by European and American studies were A. terreus and A. flavus isolates, accounting for 40.1% and 14.3% in 31 studies from Europe and 25.1% and 11.7% in 14 studies from America, respectively. The prevalence of AmB-resistant A. niger in Asian isolates was higher than in American and European. We found a low prevalence of A. terreus in American isolates (25.1%) compared to Asian (40.4%) and European (40.1%). Future studies should focus on analyzing the trend of AmBR on a regional basis and using the same methodologies.

Mucormycosis-induced upper gastrointestinal ulcer perforation in immunocompetent patients: a report of two cases

Background

Gastrointestinal mucormycosis (GIM) is a rare, opportunistic fungal infection with poor prognosis. Clinically, it is difficult to diagnose GIM owing to its nonspecific clinical symptoms and poor suspicion. The estimated incidence of GIM is inaccurate, and most cases are diagnosed accidentally during surgery or upon postmortem examination. GIM usually occurs in patients with immune deficiencies or diabetes. Here, we report two cases of immunocompetent young patients with GIM who had good prognosis after treatment. Compared to other case reports on GIM, our cases had unusual infection sites and no obvious predisposing factors, which make it important to highlight these cases.

Case presentation

The first case was that of a 16-year-old immunocompetent boy who was admitted with gastrointestinal bleeding and perforation due to a gastric ulcer. Strategies used to arrest bleeding during emergency gastroscopy were unsuccessful. An adhesive mass was then discovered through laparoscopy. The patient underwent type II gastric resection. Pathological examination of the mass revealed bacterial infection and GIM. The second case was of a 33-year-old immunocompetent woman with a recent history of a lower leg sprain. The patient subsequently became critically ill and required ventilatory support. After hemodynamic stabilization and extubation, she presented with hematemesis due to exfoliation and necrosis of the stomach wall. The patient underwent total gastrectomy plus jejunostomy. The pathology results revealed severe bacterial infection and fungal infection that was confirmed as GIM. The patient fully recovered after receiving anti-infective and antifungal treatments.

Conclusions

Neither patient was immunosuppressed, and both patients presented with gastrointestinal bleeding. GIM was confirmed via pathological examination. GIM is not limited to immunocompromised patients, and its diagnosis mainly relies on pathological examination. Early diagnosis, timely surgical treatment, and early administration of systemic drug treatment are fundamental to improving its prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01881-8.

A nanosensor for precise discrimination of nephrotoxic drug mechanisms via dynamic fluorescence fingerprint strategy

Drug-induced kidney injury causes structural or functional abnormalities of kidney, seriously affecting clinical practice and drug discovery. However, rapid and effective identification of nephrotoxic drug mechanisms is yet a challenging task arising from the complexity and diversity of various nephrotoxic mechanisms. Herein, we have constructed a polydopamine-polyethyleneimine/quantum dots sensor to instantaneously read out the nephrotoxic drugs mechanisms based on the disparate cell surface phenotypes. Cell surface components induced by multiple nephrotoxic drugs can change the fluorescence emission of multicolor quantum dots, generating their corresponding fluorescent fingerprints. The fluorescence response signatures induced by different nephrotoxic agents are gained with 84% accuracy via linear discriminant analysis. Furthermore, taking the time-toxicity relationship into consideration, dynamic fluorescent fingerprint is obtained through continuous monitoring the progress of renal cell damage, achieving 100% precise classification for nephrotoxic mechanisms of four types of antibiotics. Notably, the fluorescent fingerprint-based high-throughput sensor has been demonstrated by successfully distinguishing nephrotoxic drugs in seconds, employing a promising protocol to discriminate the specific mechanism of nephrotoxic drugs, as well as drug safety evaluation.

A Critical Review on Emerging Trends in Dry Powder Inhaler Formulation for the Treatment of Pulmonary Aspergillosis

Pulmonary aspergillosis (PA), a pulmonary fungal infection caused by Aspergillus spp., is a concern for immunocompromised populations. Despite substantial research efforts, conventional treatments of PA using antifungal agents are associated with limitations such as excessive systemic exposure, serious side effects and limited availability of the therapeutics in the lungs for an adequate duration. To overcome the limitations associated with the conventional regimens, pulmonary delivery of antifungal agents has become a focal point of research because of the superiority of local and targeted drug delivery. Dry powder inhalers and nebulized formulations of antifungal agents have been developed and evaluated for their capability to effectively deliver antifungal agents to the lungs. Moreover, progress in nanotechnology and the utilization of nanocarriers in the development of pulmonary delivery formulations has allowed further augmentation of treatment capability and efficiency. Thus, the following review provides an insight into the advantages and therapeutic potential of the utilization of nanocarriers in pulmonary delivery of antifungal agents for the treatment of PA. In addition, discussions on formulation aspects and safety concerns together with the clinical and regulatory aspects of the formulations are presented, which suggest the possibility and desirability of utilization of nanocarriers in the treatment of PA.

Improvement of the pharmacokinetic/pharmacodynamic relationship in the treatment of invasive aspergillosis with voriconazole. Reduced drug toxicity through novel rapid release formulations

Voriconazole (VCZ) is currently the first-line treatment for invasive aspergillosis, although the doses are limited by its poor solubility and high hepatic toxicity. The aim of this study was to develop a solid self-dispersing micellar system of VCZ to improve the pharmacokinetic/pharmacodynamic (PK/PD) relationship and reduce hepatotoxicity. In this work, solid micellar systems of VCZ are formulated with different polysorbate 80 ratios using mannitol as a hydrophilic carrier. The novel micellar systems were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and dissolution studies. Self-dispersing micellar systems reduced VCZ crystallinity, leading to an improvement in its dissolution rate. The in vitro susceptibility test also revealed that the most common microorganisms in invasive aspergillosis exhibited low minimum inhibitory concentration (MIC) values for micellar systems. Pharmacokinetic studies indicated an improvement in bioavailability for MS-1:3:0.05, and changes in its biodistribution to different organs. MS-1:3:0.05 showed an increased concentration in lungs and a significant decrease in VCZ accumulated in the liver.