Caracterización fisicoquímica de micafungina y anidulafungina para su administración mediante nebulización / Physicochemical characterization of micafungin and anidulafungin for its nebulized administration

Objetivo: Determinar experimentalmente si micafungina y anidulafungina poseen propiedades fisicoquímicas adecuadas para su nebulización. Método: Se determinó el pH, la osmolalidad, la viscosidad, la densidad y el contenido en cloruros mediante pH-metría, osmometría, viscosimetría, densitometría y potenciometría, respectivamente, en dos muestras de diferente concentración, 5 y 10 mg/ml, de cada equinocandina. Resultados: Para la solución de micafungina 5 mg/ml los resultados obtenidos fueron: pH 5,80 (0,14), osmolalidad 293,33 (1,53) mOsm/kg, contenido en cloruros 134,67 (0,58) mmol/l y densidad 1.009,4 (0,1) kg/m3; y para la solución de 10 mg/ml: osmolalidad 342,00 (1,00) mOsm/kg, contenido en cloruros 139,67 (0,58) mmol/l y densidad 1.014,5 (0,2) kg/m3. Para la solución de anidulafungina 5 mg/ml los resultados obtenidos fueron: pH 4,22 (0,01), osmolalidad 464,67 (2,52) mOsm/kg, contenido en cloruros 137,00 (0,00) mmol/l y densidad 1.016,5 (0,2) kg/m3; y para la solución de 10 mg/ml: osmolalidad 656,33 (1,15) mOsm/kg, contenido en cloruros 132,00 (0,00) mmol/l y densidad 1.029,8 (0,4) kg/m3. Conclusiones: Los valores de pH, osmolalidad, contenido en cloruros y densidad resultaron adecuados para una correcta tolerabilidad mediante nebulización

Objective: To determine by experimentation whether micafungin and anidulafungin possess physicochemical properties suitable for nebulization. Method: PH, osmolality, viscosity, density and chloride content were determined by pH monitoring, osmometry, viscometry, densitometry and potentiometry in two samples of different concentrations, 5 and 10 mg/mL each echinocandin. Results: The results obtained for micafungin solution were: pH 5.80 (0.14), osmolality 293.33 (1.53) mOsm/kg, chloride content 134.67 (0.58) mmol/L and density 1,009.4 (0,1) kg/m3; while for 10 mg/mL solution: osmolality 342.00 (1.00) mOsm/kg, chloride content 139.67 (0.58) mmol/L and density 1,014.5 (0.2) kg/m3. The results obtained for 5 mg/mL anidulafungin were: pH 4.22 (0.01), osmolality 464.67 (2.52) mOsm/kg, chloride content 137.00 (0.00) mmol/L and density 1,016.5 (0,2) kg/m3; while for 10 mg/mL solution: osmolality 656.33 (1.15) mOsm/kg, chloride content 132.00 (0.00) mmol/L and density 1,029.8 (0.4) kg/m3. Conclusions: PH, osmolality, chloride content and density values proved to be suitable for proper tolerability by nebulization

Chromatographic methods for echinocandin antifungal drugs determination in bioanalysis.

The increase of fungal resistance to drugs, such as azole family, gave rise to the development of new antifungals. In this context, echinocandins emerged as a promising alternative for antifungal therapies. Following the commercialization of caspofungin in 2001, echinocandins became the first-line therapy for invasive candidiasis in different patient populations. The quantification of these drugs has gained importance since pharmacokinetic/pharmacodynamic and resistance studies are a paramount concern. This fact has led us to exhaustively examine the methodologies used for the analysis of echinocandins in biological fluids, which are mainly based on LC coupled to different detection techniques. In this review, we summarize the analytical methods for the quantification of echinocandins focusing on sample treatment, chromatographic separation and detection methods.

Filter Adsorption of Anidulafungin to a Polysulfone-Based Hemofilter During CVVHD In Vitro.

Candidemia is frequent in critically ill patients, especially in combination with an acute kidney injury (AKI). Echinocandins generally are recommended for therapy of such infections. Recent studies found no need for dosage adjustment in patients with end-stage renal disease receiving hemodialysis, or patients with AKI receiving continuous venovenous hemofiltration. The aim of this in vitro study was to examine the adsorption of anidulafungin to the surface of the hemofilter during continuous venovenous hemodialysis (CVVHD) and its effect on anidulafungin concentrations. The concentration of anidulafungin in the dialyzed fluid, and the dialysate during CVVHD in vitro was examined using three different dialyzed fluids (saline; saline with 40 g/L human albumin; and a mixture of human erythrocytes and fresh frozen plasma). After the end of dialysis, the hemofilter was opened and portions of the filter capillaries were also analyzed to determine the amount of anidulafungin adsorbed. When dialyzing saline, about 99% of the anidulafungin used adsorbed to the hemofilter capillaries; in the experiments with saline with 40 g/L albumin, about 60% adsorbed to the hemofilter's surface, and when blood was dialyzed, 35% was found adsorbed after analyzing the filter capillaries. Anidulafungin was not detectable in the dialysate of any of the experiments, consequently the dialysis clearance was 0 mL/min. In conclusion, during CVVHD in vitro we found remarkable adsorption of anidulafungin to the hemofilter's surface, yet the effect on the tissue concentration needs further examination.

Isolation, identification and characterization of potential impurities of anidulafungin.

Eight impurities ranging from 0.03 to 0.97% in anidulafungin bulk drug were detected by HPLC. Four impurities (Imp-I, Imp-II, Imp-III and Imp-VIII) among impurities were isolated from the self-prepared or marketed samples of anidulafungin bulk drug by means of preparative HPLC. A thorough study was undertaken to characterize these impurities and based on 1D (1H, 13C, H-D, DEPT 90 and 135) and 2D (COSY, TOCSY, HSQC, HMBC) NMR and ESI-MS spectral data. Based on the characterization data, Imp-I was found to be known open-chain hydrolysis product formed during the synthesis and degradation. Imp-II and Imp-III was lacked a methyl group at the C-4 and C-8 in anidulafungin, respectively, whereas Imp-VIII contained a methoxy group at the C-23. The latter three new impurities were identified as process-related substances.

Equinocandinas: aspectos aplicados de la farmacología / Echinocandins: applied pharmacology

Las equinocandinas comparten las propiedades farmacodinámicas pero presentan algunas diferencias en su comportamiento farmacocinético, cuestión de interés en la práctica asistencial. No se absorben por vía oral. Su distribución en el organismo es un tanto especial ya que alcanzan concentraciones intracelulares elevadas, aunque en alguno de los fármacos puede ser reducida. Se fijan en elevada proporción a proteínas plasmáticas, por lo que al menos en el caso de la anidulafungina y la caspofungina se recomienda la administración de una dosis de carga; es discutible que no se realice con la micafungina. Se eliminan a través del metabolismo no microsómico, por lo que la concentración urinaria es muy reducida. En el proceso de eliminación biliar participan algunas proteínas transportadoras que probablemente son el origen de las interacciones descritas con la caspofungina y la micafungina. Estos dos fármacos han de ser utilizados con precaución en pacientes con alteración grave de la función hepática, pero todos ellos pueden utilizarse sin precauciones especiales cuando existe insuficiencia renal o el paciente precisa la utilización de técnicas de depuración externa (AU)

The echinocandins share pharmacodynamic properties, although there are some interesting differences in their pharmacokinetic behaviour in the clinical practice. They are not absorbed by the oral route. They have a somewhat special distribution in the organism, as some of them can reach high intracellular concentrations while, with some others, the concentration is reduced. They are highly bound to plasma proteins, thus it is recommended to administer a loading dose for anidulafungin and caspofungin, although this procedure is not yet clear with micafungin. Echinocandins are excreted via a non-microsomal metabolism, so the urinary concentration is very low. Some carrier proteins that take part in the biliary clearance process are probably involved in the interactions described with caspofungin and micafungin. These two drugs must be used with caution in patients with severely impaired hepatic function, while all of them can be used without special precautions when there is renal impairment or the patient requires renal replacement therapy (AU)

Candidiasis asociada a biopelículas / Candida biofilm-related infections

El número de dispositivos biomédicos (catéteres intravasculares, válvulas cardíacas, prótesis articulares, etc.) que se colocan en nuestros hospitales ha aumentado de manera exponencial en los últimos años. Las especies de Candida son organismos patógenos que cada vez tienen mayor relevancia en este tipo de infecciones. Candida tiene dos formas de desarrollo: planctónica y en biopelícula. Una biopelícula es una comunidad de microorganismos adheridos a una superficie y englobados por una matriz extracelular. Esta forma de desarrollo confiere a los microorganismos una gran resistencia a los agentes antimicrobianos. Esto es la causa de que los tratamientos antibióticos fracasen habitualmente y haya que retirar los dispositivos en la mayor parte de las ocasiones. Los mecanismos de adherencia inespecíficos, los sistemas de adhesina-receptor, y el sistema de comunicación intercelular denominado quorum sensing juegan un papel esencial en el desarrollo de las biopelículas de Candida. En general, los azoles tienen poca actividad frente a las biopelículas de Candida, mientras que las equinocandinas y los polienos muestran una mayor actividad. Es necesario desarrollar nuevas estrategias terapéuticas debido a la elevada morbimortalidad y el gran gasto económico asociado a este tipo de infecciones. La mayor parte de los estudios realizados hasta la fecha se han centrado en las biopelículas bacterianas. El conocimiento del proceso de formación de las biopelículas de Candida, así como su composición, es fundamental para poder desarrollar nuevas estrategias preventivas o terapéuticas (AU)

The number of biomedical devices (intravascular catheters, heart valves, joint replacements, etc.) that are implanted in our hospitals has increased exponentially in recent years. Candida species are pathogens which are becoming more significant in these kinds of infections. Candida has two forms of development: planktonic and in biofilms. A biofilm is a community of microorganisms which adhere to a surface and are enclosed by an extracellular matrix. This form of development confers a high resistance to the antimicrobial agents. This is the reason why antibiotic treatments usually fail and biomedical devices may have to be removed in most cases. Unspecific adhesion mechanisms, the adhesion-receptor systems, and an intercellular communication system called quorum sensing play an essential role in the development of Candida biofilms. In general, the azoles have poor activity against Candida biofilms, while echinocandins and polyenes show a greater activity. New therapeutic strategies need to be developed due to the high morbidity and mortality and high economic costs associated with these infections. Most studies to date have focused on bacterial biofilms. The knowledge of the formation of Candida biofilms and their composition is essential to develop new preventive and therapeutic strategies (AU)

PROYECTO ÉPICO 2.0. Desarrollo de unas recomendaciones terapéuticas educacionales mediante metodología DELPHI en pacientes críticos adultos no neutropénicos con candidiasis invasiva en situaciones especiales / EPICO 2.0 PROJECT. Development of educational therapeutic recommendations using the DELPHI technique on invasive candidiasis in critically ill adult patients in special situations

Introducción. Aunque en la última década se ha mostrado una mejoría en el manejo de la candidiasis invasiva, todavía existe controversia, especialmente en el trtaamiento antifúngico en situaciones clínicas especiales. Objetivos. Identificar los principales conocimientos clínicos y elaborar recomendaciones con un alto nivel de consenso, necesarios para la elección del tratamiento antifúngico en situaciones especiales en sus diversos escenarios en pacientes adultos críticos no neutropénicos con candidiasis invasiva. Métodos. Cuestionario prospectivo español, que mide el consenso mediante la técnica Delphi, se realizó de forma anónima y por correo electrónico con 23 expertos multidisciplinarios nacionales, especialistas en infecciones fúngicas invasivas de cinco sociedades científicas nacionales, incluyendo Intensivistas, Anestesistas, Microbiólogos, Farmacólogos y Especialistas en Enfermedades Infecciosas que respondieron a 30 preguntas preparadas por el grupo de coordinación, tras una revisión exhaustiva de la literatura de los últimos cinco años. Los objetivos educativos contemplaron cuatro categorías, incluyendo candidiasis peritoneal, pacientes inmunodeprimidos, situaciones especiales y fracasos orgánicos. El nivel de acuerdo alcanzado entre los expertos en cada uno de las categorías debería superar el 75% para ser seleccionada. En un segundo término, después de extraer las recomendaciones de los temas seleccionados, se celebró una reunión presencial con más de 60 especialistas y se les solicitó la validación de las recomendaciones pre-seleccionadas. Mediciones y Resultados Principales. En un primer término, se realizó una pre-selección de 15 recomendaciones (Candidiasis peritoneal (3), Pacientes inmunosuprimidos (6), Situaciones especiales (3), Fracasos orgánicos (3)). Después de la segunda ronda, las siguientes 13 recomendaciones fueron validadas: Candidiasis peritoneal: Debido al mal pronóstico de la peritonitis candidiásica, se recomienda un adecuado control del foco infeccioso junto a un tratamiento antifúngico precoz y apropiado. Se recomienda iniciar un tratamiento antifúngico empírico en pacientes con peritonitis secundaria nosocomial y con factores de riesgo de colonización por Candida spp. o en aquellos pacientes con peritonitis terciaria. En la peritonitis candidiásica, se recomienda utilizar una equinocandina en los pacientes inestables o en aquellos que han recibido previamente azoles o en los que se aísla Candida spp. resistente a fluconazol. Pacientes inmunodeprimidos. En el tratamiento de la candidiasis invasora con azoles en un paciente con trasplante de órgano sólido, deben considerarse sus interacciones y hepatotoxicidad. En el paciente neutropénico, la duración del tratamiento de la candidemia debe ser de 14 días desde el primer cultivo negativo y hasta la normalización de la cifra de neutrófilos. En un paciente neutropénico inestable con candidemia y catéter venoso central de fácil recambio, es aconsejable la retirada del mismo. Situaciones especiales: En el tratamiento de la candidiasis invasiva en pacientes con disfunción hepática moderada (Child B) se recomienda utilizar equinocandinas (preferentemente anidulafungina o caspofungina con ajuste de dosis) y se debe evitar el uso de azoles. Aunque las interacciones farmacológicas de las equinocandinas son pocas, se recomienda revisar la medicación concomitante y en caso de posible interacción, utilizar preferentemente anidulafungina. Fracasos orgánicos: 1.-En lo que a seguridad se refiere las equinocandinas son la familia de antifúngicos de primera elección. Todas las equinocandinas son iguales para el tratamiento de los pacientes que necesitan técnicas continuas de depuración extrarrenal y no precisan ajuste de dosis. El uso de azoles precisa importantes ajustes de dosis en el paciente en tratamiento con técnica continua o intermitente de depuración extrarrenal. Conclusiones. El manejo de la candidiasis invasiva en pacientes de UCI requiere la aplicación de los conocimientos y destrezas que se detallan en nuestras recomendaciones. Estas recomendaciones ayudan a optimizar el tratamiento de los pacientes críticos con candidiasis invasiva en distintos escenarios y situaciones clínicas y mejorar su pronóstico, basados en la metodología DELPHI (AU)

Introduction. Although there has been an improved management of Invasive Candidiasis in the last decade, still controversial issues remain, especially in different therapeutic critical care scenarios. Objectives. We sought to identify the core clinical knowledge and to achieve high agreement recommendations required to care for critically ill adult patients with Invasive Candidiasis for antifungal treatment in special situations and different scenarios. Methods. Second Prospective Spanish survey reaching consensus by the Delphi technique, conducted anonymously by electronic e-mail in the first phase to 23 national multidisciplinary experts in invasive fungal infections from five national scientific societies including Intensivists, Anesthesiologists, Microbiologists, Pharmacologists and Infectious disease specialists, answering 30 questions prepared by a coordination group after a strict review of literature in the last five years. The educational objectives spanned four categories, including peritoneal candidiasis, immunocompromised patients, special situations and organ failures. The agreement among panellists in each item should be higher than 75% to be selected. In a second phase, after extracting recommendations from the selected items, a meeting was heldwith more than 60 specialists in a second round invited to validate the preselectedrecommendations. Measurements and Main Results. In the first phase, 15 recommendations were preselected (peritoneal candidiasis (3), immunocompromised patients (6), special situations (3) and organ failures (3)). After the second round the following 13 were validated: Peritoneal candidiasis (3): Source control and early adequate antifungal treatment is mandatory; empirical antifungal treatment is recommended in secondary nosocomial peritonitis with Candida spp colonization risk factors and in tertiary peritonitis. Immunocompromised patients (5): Consider hepatotoxicity and interactions before starting antifungal treatment with azoles in transplanted patients; treat candidemia in neutropenic adult patients with antifungal drugs at least 14 days after the first negative blood culture and until normalization of neutrophil count is achieved. Caspofungin, if needed, is the echinocandin with most scientific evidence to treat candidemia in neutropenic adult patients; Caspofungin is also the first choice drug to treat febrile candidemia; in neutropenic patients with candidemia remove catheter. Special situations (2): In moderate hepatocelular failure, patients with invasive candidiasis use echinocandins (preferably low doses of anidulafungin and caspofungin) and try to avoid azoles; in case of possible interactions review all of the drugs involved and preferably use Anidulafungin. Organ failures (3): Echinocandins are the safest antifungal drugs; reconsider the use of azoles in patients under renal replacement therapy; all of the echinocandins are accepted for the treatment of patients under continuous renal replacement therapy and do not require dosage adjustment. Conclusions. Treatment of Invasive Candidiasis in ICU patients requires a broad range of knowledge and skills as summarized in our recommendations. These recommendations may help to optimize the therapeutic management of these patients in special situations and different scenarios and improve their outcome based on the DELPHI methodology (AU)

New microbiological assay for determination of caspofungin in the presence of its degradation products and its measurement uncertainty.

Caspofungin is an echinocandin antifungal used in the treatment of invasive fungal infections. Several methods have been reported for the quantitative analysis of echinocandins; however, there is no microbiological assay for determination of caspofungin potency in the presence of its degradation products. This study aimed to develop and validate a microbiological method for quantitative analysis of caspofungin in lyophilized powder, evaluate the stability, and determinate the degradation kinetics of the drug when the finished product is submitted to heat stress. A procedure was established to estimate measurement uncertainty for routine analysis. The validation was performed as recommended in the current official guidelines. The agar diffusion method is based on the inhibitory effect of caspofungin on Candida albicans. Results showed selectivity, linearity, precision, and accuracy of the method. Statistical analysis demonstrated that method is linear (in the range 2.5 to 16 microg/mL, y= 15.73 + 6.4x, r2 = 0.9965), precise (intermediate precision: 2.54%), and accurate (recovery range: 95.01-102.46%). The proposed method allowed evaluation of the thermal stability of the drug at 80 degreesC for 120 min and determination of first order degradation kinetics. The variability of inhibition zone sizes was the most important source of uncertainty at about 87% of the overall uncertainty (103.0+/-1.7%). These results show that the proposed method is applicable to routine laboratory testing, and is sensitive to thermal degradation of caspofungin.

Development of an HPLC method for the determination of anidulafungin in human plasma and saline.

An ultraviolet high-performance liquid chromatography (HPLC) method was developed to analyze anidulafungin in human plasma and saline. A reversed-phase column was used with a UV detector set at 310 nm. The mobile phase consisted of methanol and ammonium phosphate buffer at a flow rate of 1 mL/min. Micafungin was used as the internal standard. Both standard curves were linear over a range of 1 to 10 µg/mL. The intra-assay relative standard deviations (RSD) for plasma and saline matrices were 1.60-1.81% and 1.96-3.70%, respectively. The inter-assay RSD for plasma and saline matrices were 2.41-7.25% and 1.31-3.16%, respectively. This method successfully recapitulated anidulafungin plasma concentrations previously analyzed by HPLC-tandem mass spectrometry with precision and accuracy of 6.9% and 1.59%, respectively.

Nebulizer delivery of micafungin aerosols.

STUDY OBJECTIVES: To determine the optimal nebulization system for aerosolizing micafungin and to further assess the physiochemical properties of aerosolized micafungin. DESIGN: In vitro experiment. SETTING: University research center. NEBULIZERS: Pari LC Star, Hudson Updraft, Small Volume Nebulizer, and Aeroclipse II. MEASUREMENTS AND MAIN RESULTS: Using a commercially available cascade impactor, the four nebulizers were tested for their ability to deliver micafungin to the lungs. Mass median aerodynamic diameter (MMAD) and fine particle fraction (FPF) percent less than 3.3 µm (FPF(3.3)) and less than 5.8 µm (FPF(5.8)) were determined during two sampling periods for each of three trials of all nebulizers. The mean ± standard error of the mean MMAD for the nebulizers ranged from 1.93 ± 0.09 to 2.49 ± 0.25 µm; FPF(3.3) and FPF(5.8) were approximately 50% and 90%, respectively, for all nebulizers. CONCLUSION: Although all nebulizers appeared acceptable to deliver micafungin to the lungs, the Pari LC Star had the smallest MMAD and highest FPF(3.3) and FPF(5.8). These properties of the Pari LC Star should result in greater delivery of the aerosol to the lungs. Additional research on pulmonary delivery and clinical tolerability is warranted.

Rapid and sensitive liquid chromatography/mass spectrometry assay for caspofungin in human aqueous humor.

A rapid, precise, and sensitive liquid chromatography/mass spectrometry (LC/MS) method to quantify the caspofungin concentration in human aqueous humor was developed and validated. Sample preparation involved simple dilution of aqueous humor samples with acetonitrile. Azithromycin was the internal standard. Good linearity over 10 to 5,000 ng/ml was observed. The lower limit of quantification was 10 ng/ml. The intra- and interday accuracies (percent bias) were within 11%, while the intra- and interday precisions were within 6%.