Tolerability of prophylactic aerosolized liposomal amphotericin-B and impact on pulmonary function: Data from a randomized placebo-controlled trial

Amphotericin B in the Era of New Antifungals: Where Will It Stand?

Amphotericin B (AmB) has long stood as a cornerstone in the treatment of invasive fungal infections (IFIs), especially among immunocompromised patients. However, the landscape of antifungal therapy is evolving. New antifungal agents, boasting novel mechanisms of action and better safety profiles, are entering the scene, presenting alternatives to AmB's traditional dominance. This shift, prompted by an increase in the incidence of IFIs, the growing demographic of immunocompromised individuals, and changing patterns of fungal resistance, underscores the continuous need for effective treatments. Despite these challenges, AmB's broad efficacy and low resistance rates maintain its essential status in antifungal therapy. Innovations in AmB formulations, such as lipid complexes and liposomal delivery systems, have significantly mitigated its notorious nephrotoxicity and infusion-related reactions, thereby enhancing its clinical utility. Moreover, AmB's efficacy in treating severe and rare fungal infections and its pivotal role as prophylaxis in high-risk settings highlight its value and ongoing relevance. This review examines AmB's standing amidst the ever-changing antifungal landscape, focusing on its enduring significance in current clinical practice and exploring its potential future therapeutic adaptations.

Safety and usefulness of nebulized liposomal amphotericin B: Systematic scoping review

PURPOSE

Invasive fungal infections potentially result in fatal outcomes in immunocompromised hosts. Compared to intravenous administration, a nebulization therapy can achieve a high concentration of drug delivered in the respiratory tract, without a systematic absorption. We herein summarized the study findings on the safety and clinical utility of nebulized liposomal amphotericin B therapy.

METHODS

According to the PRISMA Extension for Scoping Reviews, we performed a search on MEDLINE and EMBASE for articles with relevant keywords, including "inhaled liposomal amphotericin B″, "nebulized liposomal amphotericin B″, or "aerosolized liposomal amphotericin B″, from the inception of these databases to August 31, 2022.

RESULTS

Of the 172 articles found, 27 articles, including 13 case reports, 11 observational studies, and 3 clinical trials, were selected. Generally, findings showed that nebulized liposomal amphotericin B treatment appeared to be safe and without severe adverse effects. We found an accumulated evidence for the safety, tolerability, and effectiveness of nebulized liposomal amphotericin B prophylaxis among lung transplantation recipients; however, a randomized controlled study has yet to be reported. Data on hemato-oncological patients are relatively scarce; however, a randomized controlled study suggested the prophylactic effect of nebulized liposomal amphotericin B on invasive pulmonary aspergillosis. Observational and randomized controlled studies to evaluate therapeutic efficacy of the nebulized liposomal amphotericin B therapy have not been performed.

CONCLUSION

In conclusion, we found increasing evidence for the effectiveness of the inhalation therapy among patients after lung transplantation and with hemato-oncological diseases.

Inhaled Antifungal Agents for Treatment and Prophylaxis of Bronchopulmonary Invasive Mold Infections

Pulmonary mold infections are life-threatening diseases with high morbi-mortalities. Treatment is based on systemic antifungal agents belonging to the families of polyenes (amphotericin B) and triazoles. Despite this treatment, mortality remains high and the doses of systemic antifungals cannot be increased as they often lead to toxicity. The pulmonary aerosolization of antifungal agents can theoretically increase their concentration at the infectious site, which could improve their efficacy while limiting their systemic exposure and toxicity. However, clinical experience is poor and thus inhaled agent utilization remains unclear in term of indications, drugs, and devices. This comprehensive literature review aims to describe the pharmacokinetic behavior and the efficacy of inhaled antifungal drugs as prophylaxes and curative treatments both in animal models and humans.

Conventional Antifungals for Invasive Infections Delivered by Unconventional Methods; Aerosols, Irrigants, Directed Injections and Impregnated Cement

The administration of approved antifungals via unapproved formulations or administration routes (such as aerosol, direct injection, irrigation, topical formulation and antifungal-impregnated orthopedic beads or cement) may be resorted to in an attempt to optimize drug exposure while minimizing toxicities and/or drug interactions associated with conventional (systemic) administrations. Existing data regarding such administrations are mostly restricted to uncontrolled case reports of patients with diseases refractory to conventional therapies. Attribution of efficacy and tolerability is most often problematic. This review updates prior published summaries, reflecting the most recent data and its application by available prevention and treatment guidelines for invasive fungal infections. Of the various dosage forms and antifungals, perhaps none is more widely reported than the application of amphotericin B-containing aerosols for the prevention of invasive mold infections (notably Aspergillus spp.).

An evaluation of nebulised amphotericin B deoxycholate (Fungizone® ) for treatment of pulmonary aspergillosis in the UK National Aspergillosis Centre

Antifungal treatment options for allergic bronchopulmonary aspergillosis (ABPA) and severe asthma with fungal sensitisation (SAFS) are largely limited to itraconazole based on the outcome of randomised controlled trials. It is unclear if nebulised amphotericin B deoxycholate (Fungizone^® ) is a viable therapeutic option. We evaluated the safety and efficacy of nebulised Fungizone^® in the long-term treatment of various forms of pulmonary aspergillosis. We assessed the records of 177 patients with various forms of pulmonary aspergillosis attending the National Aspergillosis Centre in Manchester who had received Fungizone^® . Patients first received a challenge test with nebulised Fungizone^® in hospital with spirometry pre/post-Fungizone^® and nebulised salbutamol given pre-Fungizone^® . Tolerability and changes in Aspergillus IgE, Aspergillus IgG and total IgE were evaluated. Sixty-six per cent (117/177) were able to tolerate the test dose of Fungizone^® and in all cases, the reason for discontinuation of the first test dose was worsening breathlessness. Twenty six (21%) stopped therapy within 4-6 weeks, and the commonest reason cited for discontinuation of therapy was increased breathlessness, hoarseness and cough. Eighteen (10.2%) patients continued the Fungizone^® for >3 months of which 5 (27.8%) recorded an improvement in total IgE, Aspergillus-specific IgE and Aspergillus IgG. Eleven had ABPA, four had SAFS, two had Aspergillus bronchitis and one had Aspergillus sensitisation with cavitating nodules. Among these 18 patients, sputum fungal culture results went from positive to negative in five patients, became positive in one patient, remained positive in three patients, and remained negative in seven patients. Nebulised Fungizone^® appears to be a poorly tolerated treatment for pulmonary Aspergillosis with high dropout rates. There appears to be both clinical and serological benefits following sustained treatment with nebulised Fungizone^® in some patients.

Novel Therapeutic Strategies Applied to Pseudomonas aeruginosa Infections in Cystic Fibrosis

Cystic fibrosis (CF) is one of the most prevalent genetic diseases and a total of 1700 different genetic mutations can cause this condition. Patients that suffer this disease have a thickening of the mucus, creating an environment that promotes bacterial infections. Pseudomonas aeruginosa is a ubiquitous bacterium, which is frequently found in the lungs of CF patients. P. aeruginosa is known for its high level of antibiotic resistance as well as its high rate of mutation that allows it to rapidly evolve and adapt to a multitude of conditions. When a CF lung is infected with P. aeruginosa, the decay of the patient is accelerated, but there is little that can be done apart from controlling the infection with antibiotics. Novel strategies to control P. aeruginosa infection are imperative, and nanotechnology provides novel approaches to drug delivery that are more efficient than classic antibiotic treatments. These drug delivery systems are offering new prospects, especially for these patients with special mucus conditions and bacterial characteristics that limit antibiotic use.

Inhaled Amphotericin B as Aspergillosis Prophylaxis in Hematologic Disease: An Update

This review summarizes the literature on inhaled amphotericin B for invasive aspergillosis prophylaxis in patients with neutropenia secondary to hematologic malignancy treatment or stem cell transplant. Six trials, 2 randomized controlled and 4 with historical controls, were identified. Three inhaled amphotericin B deoxycholate trials found a reduced invasive aspergillosis incidence, 1 reaching statistical significance. Three inhaled liposomal amphotericin B trials demonstrated similar reductions with 2 finding statistical significance. Relative risk reductions for invasive aspergillosis were routinely 40-60%. Both formulations were without reported systemic or severe adverse effects. The most common adverse events were cough, bad taste, and nausea. Discontinuation rates ranged from 0-45%. The only randomized, placebo-controlled trial utilized inhaled liposomal amphotericin B reported a nearly 60% relative risk reduction.

Inhaled liposomal amphotericin B 12.5 mg twice weekly is an alternative for invasive aspergillosis prophylaxis in high risk neutropenic patients with hematologic malignancies and stem cell transplant recipients when recommended azole agents are contraindicated or should not be used.

Aerosolized Lipid Amphotericin B for Complementary Therapy and/or Secondary Prophylaxis in Patients with Invasive Pulmonary Aspergillosis: A Single-Center Experience

BACKGROUND

Experience with aerosolized lipid amphotericin B (aeLAB) as therapy or secondary prophylaxis in patients with invasive pulmonary aspergillosis (IPA) is anecdotal.

METHODS

We performed a single-center retrospective cohort study to evaluate the efficacy of systemic antifungal therapy with and without aeLAB in patients with proven or probable IPA. Complete or partial response at 3 months was the primary end-point. Clinical response and mortality at 12 months, occurrence of adverse drug reactions and respiratory fungal colonization were secondary end-point.

RESULTS

Eleven patients (39%) received aeLAB in addition to systemic antifungal therapy (group A), and 22 (61%) received systemic antifungal therapy only (group B). The use of aeLAB was not standardized. Amphotericin B lipid complex was used in all patients but one, who received liposomal amphotericin B. Five patients received aeLAB as antifungal complementary therapy and 6 received it as secondary prophylaxis. Except for the requirement of inhaled corticosteroids and home oxygen therapy, more frequent in group A, both groups were similar in baseline conditions. A better (nonsignificant) clinical outcome was observed at 3 months in patients receiving aeLAB. Only uncontrolled baseline condition was associated with one-year mortality in univariate analysis (p = 0.002). A multivariate Cox regression analysis suggests that aeLAB, corrected for uncontrolled underlying disease, reduces mortality at 12 months (HR 0.258; 95% CI 0.072-0.922; p = 0.037).

CONCLUSION

Although no significant difference was observed in the main variable (3-month clinical response) and in spite of methodological limitations of the study, the possible survival benefit of aeLAB, adjusted for the control of the underlying disease, could justify the performance of well-controlled studies with a greater number of patients.

Small-molecule ion channels increase host defences in cystic fibrosis airway epithelia

Loss-of-function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) compromise epithelial HCO₃⁻ and Cl⁻ secretion, reduce airway surface liquid (ASL) pH, and impair respiratory host defenses in people with cystic fibrosis (CF) ^1–3. Here we report that apical addition of an unselective ion channel-forming small molecule, amphotericin B (AmB), restored HCO₃⁻ secretion and increased ASL pH in cultured human CF airway epithelia. These effects required the basolateral Na⁺/K⁺ ATPase, indicating that apical AmB channels functionally interfaced with this driver of anion secretion. AmB also restored ASL pH, viscosity, and antibacterial activity in primary cultures of airway epithelia from people with CF caused by different mutations, including ones that yield no CFTR, and increased ASL pH in CFTR-null pigs in vivo. Thus, unselective small molecule ion channels can restore CF airway host defenses via a mechanism that is CFTR-independent and therefore genotype-independent.

Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.

Inhaled anti-infective chemotherapy for respiratory tract infections: successes, challenges and the road ahead

One of the most common causes of illnesses in humans is from respiratory tract infections caused by bacterial, viral or fungal pathogens. Inhaled anti-infective drugs are crucial for the prophylaxis and treatment of respiratory tract infections. The benefit of anti-infective drug delivery via inhalation is that it affords delivery of sufficient therapeutic dosages directly to the primary site of infection, while minimizing the risks of systemic toxicity or avoiding potential suboptimal pharmacokinetics/pharmacodynamics associated with systemic drug exposure. This review provides an up-to-date treatise of approved and novel developmental inhaled anti-infective agents, with particular attention to effective strategies for their use, pulmonary pharmacokinetic properties and safety.

Aerosolised liposomal amphotericin B to prevent aspergillosis in acute myeloid leukaemia: Efficacy and cost effectiveness in real-life

Chemotherapy-induced neutropenia can be complicated by invasive pulmonary aspergillosis (IPA). In 2008, liposomal amphotericin B (L-AmB) inhalation was shown to prevent IPA in a placebo-controlled trial. Patients with acute myeloid leukaemia (AML) are the subset of haematology patients at high risk for IPA. In 2008, L-AmB inhalation prophylaxis became the standard of care for all AML patients in Erasmus MC. In this study, the efficacy and cost effectiveness of L-AmB inhalation were evaluated in a prospective cohort of AML patients. In total, 127 consecutive AML patients received chemotherapy and prophylactically inhaled L-AmB during their first and second chemotherapy cycles; 108 patients treated for AML at the same sites from 2005-2008 served as controls. A standardised diagnostic protocol was used and probable/proven IPA served as the primary endpoint. Diagnostic and therapeutic costs were also comprehensively analysed and compared. A significant decrease in probable/proven IPA in the L-AmB inhalation group was observed (L-AmB 9.5% vs. controls 23.4%; P=0.0064). Systemic antifungal therapy given at any time during the entire AML therapy decreased from 52.8% to 29.9%. Per-patient equipment and drug costs for L-AmB inhalation (1292 €/patient) were more than compensated for by a decrease in costs for diagnostics and therapeutic voriconazole use (-1816 €/patient). No serious adverse events related to L-AmB inhalation were observed. In an unselected AML patient group, L-AmB inhalation resulted in a significant and substantial decrease in IPA and was cost saving. Now that azole resistance is more frequent, non-azole-based prophylaxis may become an attractive strategy.

Aerosolized amphotericin B as prophylaxis for invasive pulmonary aspergillosis: a meta-analysis

OBJECTIVES

Invasive pulmonary aspergillosis (IPA) is associated with high mortality in high-risk (immunosuppressed) patients. Many studies have investigated whether prophylactic inhalation of amphotericin B (AMB) reduces the incidence of IPA, but no definitive conclusions have been reached. The present meta-analysis was performed to evaluate the efficacy of prophylactic inhalation of AMB for the prevention of IPA.

METHODS

MEDLINE and other databases were searched for relevant articles published until December 2013. Randomized controlled trials that compared aerosolized AMB with placebo were included. Two reviewers independently assessed and extracted the data of all trials.

RESULTS

Six animal studies and two clinical trials involving 768 high-risk patients were eligible. The animal studies showed lower overall mortality rate among animals that underwent aerosolized AMB prophylaxis (odds ratio (OR) 0.13, 95% confidence interval (CI) 0.08-0.21). Similarly, the clinical trials showed a lower incidence of IPA among patients who underwent aerosolized AMB prophylaxis (OR 0.42, 95% CI 0.22-0.79).

CONCLUSIONS

This analysis provides evidence supporting the notion that the prophylactic use of aerosolized AMB effectively reduces the incidence of IPA among high-risk patients.

Efficacy and safety of nebulised amphotericin B (NAB) in severe asthma with fungal sensitisation (SAFS) and allergic bronchopulmonary aspergillosis (ABPA)

BACKGROUND AND RATIONALE

Antifungal therapy for severe asthma with fungal sensitisation (SAFS) and allergic bronchopulmonary aspergillosis (ABPA) remains poorly studied. We assessed the efficacy and safety of NAB as second and third line therapy in SAFS and ABPA.

METHODS

21 adult asthmatics with SAFS (n = 11) and ABPA (n = 10) who had either failed itraconazole (n = 8), voriconazole proceeded by itraconazole (n = 5) or developed adverse events (AEs) to either agent (n = 7) were treated with 10mg of NAB (Fungizone) twice daily. We audited clinical and immunological response, using the Asthma Quality of Life Questionnaire (AQLQ-J) scores, asthma control, FEV1, healthcare utilisation and IgE. Patients were followed up for 12 months.

RESULTS

Twenty-one patients were treated (SAFS, n = 11) and (ABPA, n = 10), M: F = 8:12, median age 65 years (range, 24-78). The median duration of therapy was 30 days (0-1825). Clinical benefit was observed in three (14.3 %) in which overall mean AQLQ-J score improved by + 2.9, mean FEV1 improved by 0.5 L and there was improvement in overall asthma control. Seven (33%) failed initial dose (bronchospasm). Eleven (52.4%) discontinued within 12 months of therapy due to delayed bronchospasm (n = 3, within 4 weeks), equipment problems (n = 2, within 4 weeks) and lack of clinical benefit (n = 4, within 16 weeks).

CONCLUSION

Our data suggest that the overall efficacy of NAB in this group of patients is poor and associated with bronchospasm. However, the excellent response in 3 patients, suggest it may be considered when other alternatives have been exhausted. Overcoming the initial bronchospasm may improve tolerability.

Lipid-based carriers for pulmonary products: preclinical development and case studies in humans

A number of lipid-based technologies have been applied to pharmaceuticals to modify their drug release characteristics, and additionally, to improve the drug loading for poorly soluble drugs. These technologies, including solid-state lipid microparticles, many of which are porous in nature, liposomes, solid lipid nanoparticles and nanostructured lipid carriers, are increasingly being developed for inhalation applications. This article provides a review of the rationale for the use of these technologies in the pulmonary delivery of drugs, and summarizes the manufacturing processes and their limitations, the in vitro and in vivo performance of these systems, the safety of these lipid-based systems in the lung, and their promise for commercialization.

Aerosolized amphotericin B lipid complex as adjunctive treatment for fungal lung infection in patients with cancer-related immunosuppression and recipients of hematopoietic stem cell transplantation

STUDY OBJECTIVE

Aerosolized amphotericin B lipid complex (aeABLC) has been successfully used to prevent fungal disease. Experience with aeABLC as treatment of fungal lung disease is limited.

DESIGN

We evaluated the safety and efficacy of aeABLC adjunct therapy for fungal lung disease in a retrospective study of 32 immunosuppressed adults. All values are given as ± standard deviation.

SETTING

National Cancer Institute-designated Comprehensive Cancer Center.

PATIENTS

Acute leukemia (69%) and severe neutropenia (63%) were common. Fifty-six percent of patients had undergone allogeneic hematopoietic stem cell transplantation 185 ± 424 days prior to aeABLC was commenced.

MEASUREMENT AND MAIN RESULTS

High-dose corticosteroids were administered during aeABLC in 28% of patients. Fungal lung disease was proven or probable in 41% of patients. Most patients (78%) received concurrent systemic antifungal therapy for a median of 14 ± 18 days before aeABLC. The median cumulative aeABLC dose was 1050 ± 2368 mg, and the median duration of aeABLC therapy was 28 ± 130 days. Most patients (78%) received 50 mg aeABLC twice daily. Partial or complete resolution of fungal lung disease was noted in 50% of patients. In three patients (9%) modest cough, mild bronchospasm, and transient chest pain with accompanying nausea and vomiting resolved completely after discontinuation of aeABLC. No patient required hospitalization for drug toxicity or had a serious (grade III or IV) drug-related adverse event.

CONCLUSION

Treatment with aeABLC was tolerated without serious toxicity and may be considered in the setting of severe immunosuppression, cancer, and/or hematopoietic stem cell transplantation in patients with difficult-to-treat fungal lung disease.

Liposomal formulations for inhalation

No marketed inhaled products currently use sustained release formulations such as liposomes to enhance drug disposition in the lung, but that may soon change. This review focuses on the interaction between liposomal formulations and the inhalation technology used to deliver them as aerosols. There have been a number of dated reviews evaluating nebulization of liposomes. While the information they shared is still accurate, this paper incorporates data from more recent publications to review the factors that affect aerosol performance. Recent reviews have comprehensively covered the development of dry powder liposomes for aerosolization and only the key aspects of those technologies will be summarized. There are now at least two inhaled liposomal products in late-stage clinical development: ARIKACE® (Insmed, NJ, USA), a liposomal amikacin, and Pulmaquin™ (Aradigm Corp., CA, USA), a liposomal ciprofloxacin, both of which treat a variety of patient populations with lung infections. This review also highlights the safety of inhaled liposomes and summarizes the clinical experience with liposomal formulations for pulmonary application.

Amphotericin B lipid nanoemulsion aerosols for targeting peripheral respiratory airways via nebulization

Amphotericin B (AmB) lipid nanoemulsions were prepared and characterized and their suitability for pulmonary delivery via nebulization was evaluated. AmB nanoemulsions were prepared by sonicating and vortexing the drug with two commercially available lipid nanoemulsions: the Intralipid(®) or Clinoleic(®). Loading the nanoemulsions with the drug slightly increased the size of the lipid droplets and did not affect the zeta potential of the nanoemulsions. The loading efficiency of AmB was found to be 87.46±2.21% in the Intralipid(®) nanoemulsions and 80.7±0.70% in the Clinoleic(®) formulation. This respectively corresponded to 21.86 mg and 20.19 mg of AmB being successfully loaded in the nanoemulsions. On aerosolization using a Pari Sprint jet nebulizer, both nanoemulsions produced very high drug output which was approximately 90% for both formulations. Using the two-stage impinger, the Clinoleic(®) emulsion had higher fine particle fraction (FPF) than the Intralipid(®), since the Clinoleic(®) displayed higher deposition of AmB in the lower impinger stage (exceeding 80%), compared to 57% for the Intralipid(®). Overall, the ease of preparation of the AmB lipid nanoemulsions, along with their in vitro nebulization performance suggest that lipid nanoemulsions could be successful nanocarriers for delivery of AmB to the peripheral respiratory airways.

Therapeutic liposomal dry powder inhalation aerosols for targeted lung delivery

Therapeutic liposomal powders (i.e., lipospheres and proliposomes) for dry powder inhalation aerosol delivery, formulated with phospholipids similar to endogenous lung surfactant, offer unique opportunities in pulmonary nanomedicine while offering controlled release and enhanced stability. Many pulmonary diseases such as lung cancer, tuberculosis (TB), cystic fibrosis (CF), bacterial and fungal lung infections, asthma, and chronic obstructive pulmonary disease (COPD) could greatly benefit from this type of pulmonary nanomedicine approach that can be delivered in a targeted manner by dry powder inhalers (DPIs). These delivery systems may require smaller doses for efficacy, exhibit reduced toxicity, fewer side effects, controlled drug release over a prolonged time period, and increased formulation stability as inhaled powders. This state-of-the-art review presents these novel aspects in depth.

Aerosolized Delivery of Antifungal Agents

Pulmonary infections caused by Aspergillus species are associated with significant morbidity and mortality in immunocompromised patients. Although the treatment of pulmonary fungal infections requires the use of systemic agents, aerosolized delivery is an attractive option in prevention because the drug can concentrate locally at the site of infection with minimal systemic exposure. Current clinical evidence for the use of aerosolized delivery in preventing fungal infections is limited to amphotericin B products, although itraconazole, voriconazole, and caspofungin are under investigation. Based on conflicting results from clinical trials that evaluated various amphotericin B formulations, the routine use of aerosolized delivery cannot be recommended. Further research with well-designed clinical trials is necessary to elucidate the therapeutic role and risks associated with aerosolized delivery of antifungal agents. This article provides an overview of aerosolized delivery systems, the intrapulmonary pharmacokinetic properties of aerosolized antifungal agents, and key findings from clinical studies.