Mg Of Amphotericin B Research Articles

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.

Toxicities and pharmacokinetics of subconjunctival injection of liposomal amphotericin B

The toxicity of conventional formulations of amphotericin B deoxycholate (AmB(DOC)) limits its clinical applications. To reduce the toxicity of AmB(DOC), lipid formulations of amphotericin B (AmB) have been developed and clinically applied. In the present study, we evaluated the ocular toxicity and pharmacokinetics of subconjunctival injection of liposomal AmB. Subconjunctival injection of either AmB(DOC) (containing 1.5 mg of AmB and 1.2 mg of deoxycholate), deoxycholate (1.2 mg), or liposomal amphotericin B (L-AmB) (containing 1.5 mg of AmB and lipids) was given to white New Zealand rabbits. After 24 hours, toxicities of the drugs were evaluated by slit lamp and histologically. To evaluate the pharmacokinetics of subconjunctival injection of L-AmB, the concentration of the drug in the cornea was evaluated at 4, 12, 24, and 48 hours after subconjunctival injection of L-AmB, with or without corneal epithelial removal. Subconjunctival injection of AmB(DOC) or deoxycholate alone induced severe corneal and conjunctival edema, with necrosis and infiltration of inflammatory cells. In contrast, subconjunctival injection of L-AmB induced only mild inflammation near the injection site. The concentration of AmB injected in eyes with intact corneal epithelium was 4.93-2.49, 0.63-0.31, 0.15-0.07 microg/g at 4, 12, and 24 hours respectively after the injection of L-AmB. When injected in eyes after corneal epithelial removal, the concentration of AmB was 19.7-9.87, 2.49-1.25, and 1.25-0.63 microg/g at 4, 12, and 24 hours after injection respectively Subconjunctival injection of L-AmB has reduced ocular toxicities and gives satisfactory concentrations in corneal stroma compared with conventional AmB(DOC). Subconjunctival injection of L-AmB will be a choice of treatment for mycotic keratitis.

Amphotericin B Irrigation for the Treatment of Chronic Rhinosinusitis without Nasal Polyps: A Randomized, Placebo-controlled, Double-blind Study

Fungus-driven inflammation is proposed to play an important role in the pathogenesis of chronic rhinosinusitis (CRS). Previous studies tested the efficacy of intranasal antifungal agents for patients with nasal polyps. The purpose of this study was to evaluate the efficacy of intranasal amphotericin B (AMB) in patients who have CRS without nasal polyps (CRSsNP). Patients diagnosed with CRSsNP were enrolled in this study. They were assigned randomly to receive irrigation with AMB solution (20 mg of AMB in 500 mL of normal saline) or placebo (yellowish dye in 500 mL of normal saline) for 4 weeks. The outcome measures included the Chinese version of the Rhinosinusitis Outcome Measure 31 (CRSOM-31), nasal endoscopy, and bacterial and fungal cultures. Seventy patients were enrolled and 64 patients completed this study. There was significant improvement in the AMB group (n = 32) both in endoscopic (p = 0.013) and CRSOM-31 scores (p < 0.0001). The placebo group (n = 32) showed significant improvement in CRSOM-31 scores (p < 0.0001). CRSOM-31 scores were significantly lower in the AMB group than in the placebo group after 2-week treatment (p = 0.018) and remained lower after 4-week treatment, although the difference was not significant (p = 0.091). There were no significant differences in endoscopic scores and bacterial or fungal culture rates between two groups after treatment. Our results showed that AMB irrigation improved symptoms and endoscopic scores but did not show superiority to saline irrigation alone in patients who have CRSsNP.

Influence of the vehicle on the properties and efficacy of microparticles containing amphotericin B

New microparticles containing amphotericin B (AMB) have been developed and manufactured by spray drying. To this end albumin, polylactic-co-glycolic acids (PLGA) and poly(sebacic anhydride) have been employed as drug carriers. The selection of the solvent used to disperse the drug and the vehicle before spray drying was critical on production yields and physical properties of the microparticles. Once particle size, morphology and dispersability in some aqueous media were shown to be acceptable for an intravenous administration, in vivo efficacy was evaluated and compared with the reference medicine Fungizone®. Microparticles prepared with albumin, albumin heated at a high temperature, some kinds of PLGA or polyanhydride, as well as Fungizone®, were tested in an experimental hamster model of infection with Leishmania infantum, by evaluating the evolution of parasitic burdens in spleen, liver and antibody responses. After the injection of three doses corresponding to 2 mg of AMB per kilogram each, diverse reactions were reported depending on the vehicle. The best dispersability, reduction of parasites and antibody response were achieved when the treatment was performed with AMB in albumin microspheres.

Efficacious topical treatment for murine cutaneous leishmaniasis with ethanolic formulations of amphotericin B.

The goal of the present study was to evaluate the antileishmanial effects of topically applied lipid-based formulations containing amphotericin B (AmB) in CBA mice as a model for human cutaneous leishmaniasis. Such treatment, if efficacious, is expected to be superior to systemic treatments since, by acting in a localized manner, it will require lower, and therefore less toxic, drug dosages. Three preparations of AmB complexed to polar lipids were tested: Fungizone (mixed micelles composed of AmB and deoxycholate), Amphocil (AmB and cholesteryl sulfate complex), and ABPLC (AmB and phospholipid complex). All these formulations killed parasites in vitro with similar efficacies but were ineffective when they were applied topically. However, Amphocil and ABPLC, but not Fungizone, when dispersed in an aqueous solution containing 5 to 25% ethanol, induced a statistically significant improvement in lesion size from week 2 or 3 onward (a total of 15 mg of AmB per kg of body weight was applied over 3 weeks). AmB biodistribution measurements following topical application of Amphocil, determined by high-pressure liquid chromatography, showed that AmB was detectable in the skin but not in the internal organs. Application of at least 10 times more drug was necessary to obtain detectable levels of AmB in the internal organs. After application of therapeutic doses of ABPLC, very low levels of AmB were detected in the internal organs. These experiments show for the first time that AmB administered topically as a complex either with cholesteryl sulfate or with phospholipids and in the presence of ethanol can penetrate the skin and kill sensitive organisms in a localized manner by using very low total drug concentrations.

Intra‐articular Anesthesia of the Distal Interphalangeal Joint Alleviates Lameness Associated With the Navicular Bursa in Horses

To determine if intra-articular anesthesia of the distal interphalangeal joint could alleviate lameness associated with the navicular bursa in horses. Experimental investigation. Six clinically normal horses. Lameness was induced in each horse by injecting either the left or right front navicular bursa with 5 mg of amphotericin-B. Forty-eight hours later each horse was videotaped walking and trotting before, and 5, 30, and 60 minutes after injecting the distal interphalangeal joint of the treated limb with 5 mL of 2% mepivacaine hydrochloride. All video recordings were then rerecorded onto master tapes in a random sequence. Four clinicians, unaware of the animal identity related to observation time or limb treated, independently viewed these tapes and graded the lamenesses. There was a significant reduction in lameness 5 and 30 minutes after anesthetic was injected into the distal interphalangeal joint. Lameness scores 60 minutes after anesthetic administration were not significantly different than baseline values. Gross pathological examination confirmed marked inflammation of the treated navicular bursae and normal appearance of the distal interphalangeal joints. Intra-articular anesthesia of the distal interphalangeal joint can alleviate lameness associated with the navicular bursa. Intra-articular anesthesia of the distal interphalangeal joint is not specific only for lameness originating in the distal interphalangeal joint.

Evaluation of renal toxicity and antifungal activity of free and liposomal amphotericin B following a single intravenous dose to diabetic rats with systemic candidiasis.

Since fungal infections are prevalent in diabetic patients, in whom treatment is often complicated by underlying renal disease and dyslipidemias, the purpose of the present study was to determine if the antifungal activity and nephrotoxic effects of amphotericin B (AmB) and liposomal AmB (L-AmB) are different in nondiabetic (normolipidemic) rats compared with those in diabetic (dyslipidemic) rats with systemic candidiasis. Non diabetic and diabetic rats infected with Candida albicans received a single intravenous dose of either AmB (0.8 mg of AmB per kg of body weight), L-AmB (0.8, 2, or 4 mg of AmB per kg), or an equivalent volume of normal saline (1 ml). Renal function was assessed by insulin clearance, and antifungal activity was determined by measuring the numbers of CFU of C. albicans that were present in the right kidney following drug treatment. AmB at 0.8 mg/kg and L-AmB at 0.8, 2, and 4 mg/kg are effective antifungal agents in both diabetic and nondiabetic rats. However, while there was approximately a 4-fold decline in the mean number of CFU per gram of kidney in nondiabetic rats, there was only approximately a 2.5-fold decline for the comparable dose (AmB, 0.8 mg/kg) in diabetic rats. There also appeared to be a similar fold reduction of L-AmB at all of the dosages tested. AmB treatment significantly improved renal function in diabetic and nondiabetic rats with systemic candidiasis. Although L-AmB at all doses tested significantly improved renal function in diabetic rats with systemic candidiasis, only L-AmB at doses of 2 and 4 mg/kg significantly improved renal function in nondiabetic rats with systemic candidiasis. These findings suggest that following administration of a single intravenous dose, AmB and L-AmB appear to be less effective in killing C. albicans isolates in diabetic than in nondiabetic rats, while they were found to improve the renal functions of rats in both treatment groups.

Amphotericin B liposomes with prolonged circulation in blood: in vitro antifungal activity, toxicity, and efficacy in systemic candidiasis in leukopenic mice.

Pegylated amphotericin B (AmB) liposomes (PEG-AmB-LIP) were compared with laboratory-prepared nonpegylated AmB liposomes (AmB-LIP), a formulation with a lipid composition the same as that in AmBisome, as well as with industrially prepared AmBisome regarding their in vitro antifungal activities, toxicities, blood residence times, and therapeutic efficacies. Killing of Candida albicans (> 99.9%) during short-term (6-h) incubation was observed at 0.2 mg of AmB per liter for AmB desoxycholate, 0.4 mg of AmB per liter for PEG-AmB-LIP, 0.8 mg of AmB per liter for AmB-LIP, and 12.8 mg of AmB per liter for AmBisome. The maximum tolerated doses of PEG-AmB-LIP, AmB-LIP, and AmBisome were 15, 19, and > 31 mg of AmB per kg of body weight, respectively. In contrast to AmB-LIP, the blood residence time of PEG-AmB-LIP was prolonged and dose independent. In a model of systemic candidiasis in leukopenic mice at a dose of 5 mg of AmB per kg, PEG-AmB-LIP was completely effective and AmB-LIP was partially effective, whereas AmBisome was not effective. AmB-LIP at 11 mg of AmB per kg was partially effective. AmBisome at 29 mg of AmB per kg was completely effective. In conclusion, the therapeutic efficacies of AmB liposomes can be improved by preparing AmB liposomes in which a substantial reduction in toxicity is achieved while antifungal activity is retained. In addition, therapeutic efficacy is favored by a prolonged residence time of AmB liposomes in blood.

Treatment of murine cryptococcal meningitis with an SCH 39304-amphotericin B combination

Cryptococcal meningitis was induced in BALB/c mice by intracerebral infection with Cryptococcus neoformans. Drug therapy was initiated 1 day later, with mice receiving amphotericin B (AMB), SCH 39304, combination therapy, or no drug therapy (controls). Most, but not all, combinations showed additive benefits, significantly prolonging survival and reducing organism counts in tissues compared with those in controls and groups which received the drugs independently. Optimum protection was obtained when a single dose of 10 mg of AMB per kg of body weight was combined with a fairly narrow SCH 39304 dose range. AMB antagonism did not occur with any regimen tested. AMB-azole combinations may be reasonable alternatives for patients who fail standard cryptococcosis therapeutic regimens.

Limited protection by small unilamellar liposomes against the renal tubular toxicity induced by repeated amphotericin B infusions in rats

Amphotericin B (AMB), either alone or incorporated into small unilamellar vesicles of pure dipalmitoylphosphatidyl choline (DPPC SUV-AMB), was administered intravenously to male Sprague-Dawley rats once daily for 5 days. Either 1.5 or 3.5 mg of AMB or DPPC SUV-AMB per kg was given, since these concentrations corresponded, respectively, to the lowest nephrotoxic dose and the sublethal dose of AMB in our model. Tubular functions were evaluated daily, and AMB concentrations in plasma, urine, and tissues were measured by high-performance liquid chromatography. AMB at both doses induced tubular toxicity, hyposthenuria being the earliest symptom. DPPC SUV-AMB at 1.5 mg/kg/day was atoxic, but the tubular alterations induced by 3.5 mg of DPPC SUV-AMB per kg were similar to those observed with 3.5 mg of AMB per kg, except that the ability to concentrate urine was partly restored 72 h after the last infusion. Incorporating AMB into DPPC SUV did not influence the pharmacokinetics of the drug. Using this lipidic AMB formulation, we thus observed a beneficial effect toward limiting the renal tubular toxicity of repeated low doses of AMB but, unexpectedly, not that of high doses. These results indicate that tubular renal functions and electrolyte serum values should be closely monitored in patients treated with AMB liposomal formulations, especially high-dose regimens.

Comparative effects of cilofungin and amphotericin B on experimental murine candidiasis

The effectiveness of cilofungin (LY121019, referred to hereafter as LY), a lipopeptide, was studied in a murine candidiasis model. CD-1 mice (5 weeks old) were injected intravenously with 3 x 10(5) Candida albicans yeast cells. Intraperitoneal LY or amphotericin B (AmB) therapy was begun 4 days after infection and was continued daily for 2 weeks. LY and AmB were compared at 62.5, 6.25, and 0.625 mg/kg per day, with the LY dose split into two treatments per day. Mice were observed for 30 days postinfection, and survivors were necropsied. AmB at 62.5 mg/kg per day was lethal in the absence of infection. Cumulative mortality for infected controls was 94% (17 of 18). Survival of mice treated with the control diluent for LY was the same as survival with no treatment. Survival after 0.625 mg of LY per kg per day was the same as that of the controls, and 6.25 or 62.5 mg of LY per kg per day was significantly superior. AmB treatment at 0.625 or 6.25 mg/kg per day was protective and superior to the same LY doses. Atrophied kidneys were common in AmB-treated mice, and mice treated with 6.25 mg of AmB per kg per day appeared ill during therapy. The number of CFU recovered from kidneys and spleens of surviving mice reflected the same relationships between drugs and doses as those described for mortality. C. albicans was not cleared from the kidneys of mice in any group, and only in the 6.25-mg/kg-per-day AmB treatment group was not detectable C. albicans found in the spleens. These data indicate that LY or AmB suppresses candida infection but neither is curative in this model.