title: Influence of the freeze-drying process on the physicochemical and biological properties of pre-heated amphotericin B micellar systems.
abstract: The moderate heat treatment of amphotericin B (AmB) in its micellar form (M-AmB) results in superaggregates (H-AmB) that present a substantially lower toxicity and similar activity. The aim of this work was to evaluate the H-AmB behavior after a freeze-drying process. H-AmB and M-AmB micelles were evaluated before and after freeze-drying concerning their physicochemical and biological properties by spectrophotometry and activity/toxicity assay, respectively. Four concentrations of M-AmB and H-AmB were studied aiming to correlate their aggregation state and the respective biological behavior: 50 mg L(-1), 5 mg L(-1), 0.5 mg L(-1), and 0.05 mg L(-1). Then, potassium leakage and hemoglobin leakage from red blood cells were used to evaluate the acute and chronic toxicity, respectively. The efficacy of M-AmB and H-AmB formulations was assessed by potassium leakage from Candida albicans and by the broth microdilution method. After heating, in addition to an evident turbidity, a slight blueshift from 327 to 323 nm was also observed at the concentrations of 50 and 5 mg L(-1) for H-AmB. Additionally, an increase in the absorbance at 323 nm at the concentration of 0.5 mg L(-1) was detected. Concerning the toxicity, H-AmB caused significantly lower hemoglobin leakage than M-AmB. These results were observed for H-AmB before and after freeze-drying. However, there was no difference between H-AmB and M-AmB concerning their activity. Accordingly, the freeze-drying cycle did not show any influence on the behavior of heated formulations, highlighting the suitability of such a method to produce a new AmB product with a long shelf life and with both greater efficiency and less toxicity.
authors: Programa de Pós-graduação em Ciências da Saúde, Centro de Ciências da Saúde (CCS), Laboratório de Sistemas Dispersos (LASID), Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN, Brazil.
authors: Scheyla D V S
authors: SD
authors: Siqueira
authors: Miguel A
authors: MA
authors: Silva-Filho
authors: Christian A
authors: CA
authors: Silva
authors: Ivonete B
authors: IB
authors: Araújo
authors: Acarilia E
authors: AE
authors: Silva
authors: Matheus F
authors: MF
authors: Fernandes-Pedrosa
authors: Anselmo G
authors: AG
authors: Oliveira
authors: E Sócrates T
authors: ES
authors: Egito
mesh_terms: D000666:Amphotericin B / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002626:Chemistry, Pharmaceutical; D004305:Dose-Response Relationship, Drug; D004355:Drug Stability; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D005612:Freeze Drying; D006454:Hemoglobins / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D008823:Micelles; D011188:Potassium / Q000097:blood; D013056:Spectrophotometry, Ultraviolet; D013678:Technology, Pharmaceutical / Q000379:methods*; D013997:Time Factors
chemical_list: D000935:Antifungal Agents; D006454:Hemoglobins; D008823:Micelles; D000666:Amphotericin B; D011188:Potassium