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PubMed1991

Comparative in vitro effects of liposomal amphotericin B, amphotericin B-deoxycholate, and free amphotericin B against fungal strains determined by using MIC and minimal lethal concentration susceptibility studies and time-kill curves.

Multilamellar liposomal amphotericin B (L-AmB) was generally less active in vitro against yeast strains than was amphotericin B-deoxycholate or free amphotericin B, although continual agitation of the broth disproportionately increased the activity of L-AmB. Time-kill studies also demonstrated a slower onset of action of L-AmB and supported the hypothesis that liposomes may act as reservoirs for free amphotericin B, which is the active moiety.

Amphotericin B↗
PubMed2001

Determination of amphotericin B, liposomal amphotericin B, and amphotericin B colloidal dispersion in plasma by high-performance liquid chromatography.

Amphotericin B is a potent polyene antifungal drug for intravenous treatment of severe infections. It is used as amphotericin B-deoxycholate and in order to reduce amphotericin B toxicity as lipid-formulated complex (liposomal or colloidal dispersion). A sensitive and specific analytical method is presented for the separation of lipid-complexed and plasma protein-bound amphotericin B in human heparinized plasma. This separation, which is required for pharmacokinetic studies, is achieved by solid-phase extraction (SPE) via Bond Elut C18. The protein-bound amphotericin B has a higher affinity to the SPE material and is therefore retained, whereas the lipid-complexed amphotericin B is eluted in the first step. The recovery of the SPE was >75% for high concentrations and >95% for low concentrations. Quantification was performed by reversed-phase HPLC using a LiChrosorb-RP-8 column, UV detection (lambda=405 nm) and a mixture of acetonitrile-methanol-0.010 M NaH2PO4 buffer (41:10:49, v/v) as mobile phase. The retention time for amphotericin B under the given conditions was 6.7 min. The calibration curves were found to be linear (r > or = 0.999) in two different ranges (5.0-0.50 microg/ml and 0.50-0.005 microg/ml). Intra- and inter-day precision and accuracy fulfilled the international requirements. No interference from other drugs (typical broad medication for intensive-care patients) or common plasma components was detected in >400 samples analyzed.

Amphotericin B↗
PubMed1999

In-vitro antifungal activity of liposomal nystatin in comparison with nystatin, amphotericin B cholesteryl sulphate, liposomal amphotericin B, amphotericin B lipid complex, amphotericin B desoxycholate, fluconazole and itraconazole.

The in-vitro susceptibilities of 120 clinical isolates of yeasts to liposomal nystatin were compared with those to amphotericin B lipid complex (ABLC), liposomal amphotericin B (LAB), amphotericin B cholesteryl sulphate (ABCD), amphotericin B desoxycholate, nystatin, fluconazole and itraconazole. Yeast isolates examined included strains of Candida albicans, Candida parapsilosis, Candida glabrata, Candida krusei, Candida guilliermondii, Candida tropicalis, Candida kefyr, Candida viswanathii, Candida famata, Candida rugosa, Rhodotorula rubra, Trichosporon spp., Cryptococcus laurentii and Cryptococcus neoformans. The mean MICs for all strains examined were: liposomal nystatin 0.96 mg/L; nystatin 0.54 mg/L; ABLC 0.65 mg/L; LAB 1.07 mg/L; ABCD 0.75 mg/L; amphotericin B 0.43 mg/L; fluconazole 5.53 mg/L; and itraconazole 0.33 mg/L. No significant differences were seen between the activity of liposomal nystatin and the polyene drugs or itraconazole, but liposomal nystatin was more active than fluconazole. MICs were lower than the reported blood concentrations following therapeutic doses of this drug, indicating the potential for a therapeutic use of liposomal nystatin in humans. These results indicate good activity in vitro against medically important yeasts, which compares favourably with the activities of other currently available antifungal drugs. Liposomal nystatin may have a role in the treatment of disseminated and systemic mycoses.

Amphotericin B↗
PubMed1999

Dose range evaluation of liposomal nystatin and comparisons with amphotericin B and amphotericin B lipid complex in temporarily neutropenic mice infected with an isolate of Aspergillus fumigatus with reduced susceptibility to amphotericin B.

Using an isolate of Aspergillus fumigatus that is less susceptible in vivo to amphotericin B than most other isolates, we compared different doses of liposomal nystatin (L-nystatin), liposomal amphotericin B (L-amphotericin), and amphotericin B lipid complex (ABLC) with amphotericin B deoxycholate. Four experiments with intravenously infected neutropenic mice were conducted. A dose of L-nystatin at 10 mg/kg of body weight was toxic (the mice had fits or respiratory arrest). The optimal dosage of L-nystatin was 5 mg/kg daily on days 1, 2, 4, and 7 (90% survival). This was superior to L-amphotericin (5 mg/kg [P = 0.24] and 1 mg/kg [P < 0.0001]), ABLC (5 mg/kg [P = 0.014] and 1 mg/kg [P < 0.0001]), and amphotericin B deoxycholate (5 mg/kg [P = 0.008]). In terms of liver and kidney cultures, L-nystatin (5 mg/kg) was superior to all other regimens (P = 0.0032 and <0.0001, respectively). Higher doses of L-amphotericin (25 and 50 mg/kg) in one earlier experiment were more effective (100% survival) than 1 mg of L-amphotericin per kg and amphotericin deoxycholate (5 mg/kg) in terms of mortality and both liver and kidney culture results and to L-amphotericin (5 mg/kg) in terms of liver and kidney culture results only. ABLC (25 mg/kg) given daily for 7 days was superior to ABLC (50 mg/kg [P = 0.03]) but not to ABLC at 5 mg/kg or amphotericin B deoxycholate in terms of mortality, although it was in terms of liver and kidney culture results. No dose-response for amphotericin B (5 and 1 mg/kg) was demonstrable. In conclusion, in this stringent model, high doses of L-amphotericin and ABLC could overcome reduced susceptibility to amphotericin B deoxycholate, but all were inferior to 5- to 10-fold lower doses of L-nystatin.

Amphotericin B↗
PubMed1975

Comparative chemotherapeutic activity of amphotericin B and amphotericine B methy ester.

The comparative efficacy of amphotericin B and amphotericin B methyl ester (AME) against experimental histoplasmosis, blastomycosis, cryptococcosis, and candidosis in mice was assessed by determining the effect of daily intraperitoneal therapy on 21-day survival and persistence of organisms in internal organs. AME, like amphotericin B, was effective against each of the experimental infections, but the efficacy was lower than the parent compound. For Histoplasma and Blastomyces infections the mean effective dose (ED(50)) of amphotericin B was 0.3 mg/kg, whereas the corresponding values for AME, respectively, were 2.4 and 2.8 mg/kg. For Cryptococcus infection the ED(50) for amphotericin B was 0.2 mg/kg compared with 2.0 mg/kg for AME. The ED(50) of amphotericin B for Candida infection was lower than 0.05 mg/kg and the value of AME was between 0.5 to 0.05 mg/kg. The colony counts from internal organs of the surviving animals after the therapeutic regimens were compatible with the data on survival.

Amphotericin B↗
PubMed1975

Stability studies with amphotericin B and amphotericin B methyl ester.

In solid form, amphotericin B and amphotericin B methyl ester free base exhibit similar stability. Acid salts of the methyl ester derivative stored under identical conditions are less stable. In solution, amphotericin B is generally more stable than its methy ester salts. However, when pH is adjusted to 6.0 and storage temperature held at 5 degrees C the methyl ester salts reflect the stability exhibited by the parent compound, amphotericin B.

Amphotericin B↗
PubMed1976

Comparison of amphotericin B and amphotericin B methyl ester: efficacy in murine coccidioidomycosis and toxicity.

The methyl ester of amphotericin B was compared with the parent compound, amphotericin B, in terms of therapeutic efficacy in experimental murine coccidioidomycosis and of toxicity. Infections were established by intraperitoneal or intratracheal inoculation with arthrospores. The mice were given either intraperitoneal or intravenous injections of drug for 30 days, according to several dosage schedules. At low doses, amphotericin B methyl ester was less effective therapeutically than was amphotericin B; however, at higher doses, amphotericin B was directly lethal and/or nephrotoxic, whereas the methyl ester was therapeutically effective and nontoxic. In contrast to amphotericin B, the methyl ester did not cause either azotemia or histopathologic changes in the kidneys.

Amphotericin B↗
PubMed1978

Comparative susceptibility of four kinds of pathogenic fungi to amphotericin B and amphotericin B methyl ester.

The activity of amphotericin B methyl ester was compared with that of amphotericin B, using Candida albicans (34 isolates), Torulopsis glabrata (12 isolates), Filobasidiella neoformans (stat. conid. Cryptococcus neoformans) (14 isolates), and Coccidioides immitis (37 isolates) and tube dilution in a totally synthetic, completely defined medium (SAAMF) with inocula of 10(4) colony-forming units per ml. Minimal inhibitory concentrations were read after 24 h at 34 degrees C for C. albicans and T. glabrata, and after 48 h at 34 degrees C for C. immitis and F. neoformans. Minimal lethal concentrations were determined by subculture of 10% of the volume of the cultures without evident growth onto Sabouraud glucose agar medium. Overall, amphotericin B methyl ester was slightly less active than amphotericin B, with the differences attaining statistical significance for: (i) inhibition of C. albicans and T. glabrata and (ii) killing of T. glabrata.

Amphotericin B↗
PubMed1994

In vitro and in vivo antifungal activities of liposomal amphotericin B, and amphotericin B lipid complex.

The in vitro and in vivo antifungal activities of liposomal amphotericin B (L-AMPH) and amphotericin B lipid complex (ABLC), which is composed of amphotericin B and the phospholipids dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol, were compared with those of conventional amphotericin B (Fungizone, AMPH). The acute intravenous toxicity was markedly lower in BALB/c mice; 50% lethal doses (LD50s) were 2.75 mg/kg in AMPH, 32.9 mg/kg in L-AMPH and > 75 mg/kg in ABLC. In vitro antifungal activities against Candida albicans, C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei were evaluated by the agar plate dilution method. The activities were unchanged against C. albicans, but MICs increased more than four fold in 18 of the 20 strains other than C. albicans in L-AMPH and in 9 of the 20 in ABLC. L-AMPH and ABLC were as efficacious as AMPH in the treatment of mice infected with C. albicans, and at a dose of 0.5 and 1.0 mg/kg of body weight, ABLC was more efficacious on survival A ten-times larger dose (10 mg/kg) of L-AMPH and ABLC was administered to mice with 100% survival, suggesting improved tolerability as compared to amphotericin B.

Amphotericin B↗
PubMedDate not supplied

Amphotericin B versus amphotericin B plus 5-flucytosine: poor results in the treatment of proven systemic mycoses in neutropenic patients.

Twenty-eight neutropenic (< 500 granulocytes/microliters) adults with microbiologically or histologically proven systemic mycosis were randomly assigned to receive either amphotericin B alone (0.5 mg/kg/day; n = 14) or amphotericin B (0.5 mg/kg/day) plus 5-flucytosine (150 mg/kg/day; n = 14) intravenously. Therapy was given for an average duration of 10 days in both groups, amounting to a total dose of amphotericin B of 338 mg and 308 mg, respectively. The mean duration of granulocytopenia was 18 days in the amphotericin B group and 20 days in the combination group. Only two patients treated with amphotericin B alone and three given the combination survived. Adverse events were similar in both groups with an elevation of the serum creatinine in six cases during the administration of amphotericin B alone and in seven cases treated with the combination. No other serious adverse events were encountered. Treatment with both regimens was disappointing partly because mycosis was too far advanced by the time therapy was begun and neutrophils were recovered in only half the patients.

Adult↗
PubMed1976

Amphotericin B and amphotericin B methyl ester ascorbate. I. Chemotherapeutic activity against Candida albicans, Cryptococcus neoformans, and Blastomyces dermatitidis in mice.

Amphotericin B methyl ester (AME) has been reported to possess in vitro antifungal activity similar to that of amphotericin B and to have less intrinsic toxicity in mice and dogs. For these reasons AME has been porposed as an alternative to amphotericin B in the therapy of deep mycoses. For comparison of the therapeutic efficacy of the two polyenes in laboratory animals before initiation of studies in humans, groups of mice were infected with Candida albicans, Cryptococcus neoformans, and Blastomyces dermatitidis. Treatment consisted of two or more doses of each drug given by the intravenous route. Concurrently, studies of subacute toxicity were conducted in the same species to permit calculation of therapeutic indices. These studies have shown that AME, as the ascorbate salt, is substantially less efficacious than amphotericin B (in colloidal dispersion with sodium deoxycholate) for treatment of the fungal infections and that amphotericin B had a higher therapeutic ratio for all infections studied than did AME.

Amphotericin B↗
PubMed1975

Comparative in vitro antifungal activity of amphotericin B and amphotericin B methyl ester.

The in vitro antifungal activity of amphotericin B methyl ester (AME), a water-soluble derivative of amphotericin B, was compared to that of the parent compound against a variety of pathogenic and potentially pathogenic fungi. AME has a significant antifungal activity, but the activity of AME was slightly lower than that of amphotericin B. Among the yeast-like organisms, only the yeast cells of Sporothrix schenckii were more resistant than others to both antibiotics, with a minimal fungicidal concentration of 5 to 10 mug/ml. The yeast cells of other fungi were killed at concentrations of 1 mug or less of either antibiotic per ml. The filamentous forms of S. schenckii and Oidiodendron kalrai were more resistant than the filamentous forms of other dimorphic fungi to both drugs. The minimal fungicidal concentration for S. schenckii was 10 mug/ml and for O. kalrai, 50 mug/ml. The dermatophytes, phycomycetes, and dematacious and other potentially pathogenic fungi were inhibited fairly well by both drugs, but up to 50 mug/ml was required for fungicidal action. The water solubility and wide spectrum of antifungal activity of AME warrant evaluation of its chemotherapeutic activity against experimental fungal infections.

Amphotericin B↗
PubMed1977

Comparative susceptibility of Candida albicans to amphotericin B and amphotericin B methyl ester.

The in vitro antifungal activities of amphotericin B (AMB) and amphotericin B methyl ester (AME) were compared against 465 clinical isolates of Candida albicans. AMB and AME possessed comparable activity against half of the strains, but against the remainder of the strains the activity of AME was slightly lower than that of AMB. Rarely did AME show superior antifungal activity to AMB.

Amphotericin B↗
PubMed2000

A randomized, double-blind comparative trial evaluating the safety of liposomal amphotericin B versus amphotericin B lipid complex in the empirical treatment of febrile neutropenia. L Amph/ABLC Collaborative Study Group.

In this double-blind study to compare safety of 2 lipid formulations of amphotericin B, neutropenic patients with unresolved fever after 3 days of antibacterial therapy were randomized (1:1:1) to receive amphotericin B lipid complex (ABLC) at a dose of 5 mg/kg/d (n=78), liposomal amphotericin B (L Amph) at a dose of 3 mg/kg/d (n=85), or L Amph at a dose of 5 mg/kg/d (n=81). L Amph (3 mg/kg/d and 5 mg/kg/d) had lower rates of fever (23.5% and 19.8% vs. 57.7% on day 1; P<.001), chills/rigors (18.8% and 23.5% vs. 79.5% on day 1; P<.001), nephrotoxicity (14.1% and 14.8% vs. 42.3%; P<.01), and toxicity-related discontinuations of therapy (12.9% and 12.3% vs. 32.1%; P=.004). After day 1, infusional reactions were less frequent with ABLC, but chills/rigors were still higher (21.0% and 24.3% vs. 50.7%; P<.001). Therapeutic success was similar in all 3 groups.

Adolescent↗
PubMed1982

Comparative sensitivity of Naegleria fowleri to amphotericin B and amphotericin B methyl ester.

Data presented showed that Naegleria fowleri is much more sensitive to amphotericin B (AmB) than to amphotericin B methyl ester (AME). In vitro, AME was effective at concentrations of 1.0 microgram/ml whereas the parent antibiotic, AmB, was effective at concentrations of 0.0125 to 0.025 microgram/ml. In vivo, AmB, at a concentration of 2.5 mg/kg/day, produced 100% survival in mice infected with N. fowleri, but AME failed to protect infected mice even at concentrations of 30 mg/kg/day. The results support previous observations with fungi which have shown that AmB is a more potent antimicrobial agent than AME.

Amoeba↗
PubMed1981

Ketoconazole, amphotericin B, and amphotericin B methyl ester: comparative in vitro and in vivo toxicological effects on neutrophil function.

We investigated a number of parameters for host defense after the in vitro addition of the antifungal agents ketoconazole, amphotericin B (AMB), and amphotericin B methyl ester (AME). Similar assays were repeated before and after patients received the former two drugs. Viability by trypan blue exclusion, adherence by nylon wool columns, chemotaxis by the under-agarose technique, phagocytosis and killing by chemiluminescence, colony counts, and acridine orange direct visualization were assayed. In striking contrast to AMB and AME, ketoconazole demonstrated no significant effect on neutrophils. Adherence in the presence of therapeutic plasma levels of AMB and AME was decreased (P less than or equal to 0.005) at low drug concentrations, whereas at higher concentrations, adherence was increased (P less than 0.001). The chemotactic responses of cells incubated with AMB and AME demonstrated marked suppression. Phagocytic capacity and killing were decreased (P less than or equal to 0.005) with AMB as compared with control assays and assays performed in the presence of ketoconazole and AME. However, no difference were observed between two patients who received AMB and two other treated with ketoconazole.

Amphotericin B↗
PubMed2006

Deoxycholate amphotericin B and amphotericin B lipid complex exert additive antifungal activity in combination with pulmonary alveolar macrophages against Fusarium solani.

Fusarium spp. have emerged as important causes of invasive fungal infections in immunocompromised patients. Rabbit pulmonary alveolar macrophages (PAMs) exhibited fungicidal activity against conidia of Fusarium solani and achieved a time-dependent increase in killing. Neither deoxycholate amphotericin B (DAMB) nor amphotericin B lipid complex (ABLC) exerted a suppressive effect on PAMs by decreasing their conidiocidal activity against F. solani. On the contrary, at a concentration of 0.125 microg ml(-1), ABLC and, to a lesser degree, DAMB additively augmented the fungicidal activity of pulmonary alveolar macrophages against conidia of Fusarium solani.

Amphotericin B↗
PubMed1990

Effect of nystatin, amphotericin B and amphotericin B methyl ester on Saccharomyces cerevisiae with different lipid composition.

Saccharomyces cerevisiae was cultured under anaerobiosis in semi-complete medium to which either palmitoleic or oleic acid was added. Cells were grown at 20 degrees C or 30 degrees C. The levels of total lipids, total sterols, and phospholipids were higher in cells grown at 20 degrees C than at 30 degrees C. The effects of nystatin (NYS), amphotericin B (AMB), and amphotericin B methyl ester (AME) were evaluated by determining cell viability and liberation of intracellular compounds. The loss of cell viability is higher in the first 30 minutes of incubation with the drugs and is the same regardless of the type of cells obtained. Low molecular weight compounds and ions such as K+ are liberated a few minutes after incubation with the drugs whereas proteins and substances absorbing at 260 nm are liberated later. Phosphate liberation comes after K+ and before compounds of higher molecular weights.

Amphotericin B↗