RESUMO
This paper uses several preparation methods, such as thin-film, reverse-phase evaporation and freeze-thawing methods, and also compares encapsulation percentage of Ara-A in liposome (EN%) of these methods. The best operational conditions of preparing liposome-encapsulated Ara-A are explored. A higher EN%, about 50%, which is ten times that reported in foreign literature, is obtained by using improved freeze-thawing method, and this method is easy to operate and repeatable. At the same time, the physical and chemical stabilities of the liposome-encapsulated Ara-A were observed. The result shows that there are no distinct changes in shape, size distribution of liposome, and EN% as well as Ara-A contained in liposome by means of sterilization at 100 degrees C for 30 minutes. Accelerating test at a constant temperature indicates that liposome-entrapped Ara-A has certain chemical stability.
Assuntos
Vidarabina/administração & dosagem , Estabilidade de Medicamentos , Lipossomos , Tamanho da PartículaRESUMO
After i.v. free harringtonine (FH) and harringtonine liposomes (HL) with high and low encapsulation percentage (En%) to rabbits, their blood concentrations were determined by reverse-phase HPLC. The blood concentration-time curves were shown to fit a two-compartments open model. FH: T1/2 alpha = 1.32 +/- 0.24, T1/2 beta = 32 +/- 6 min; Low En % HL: T1/2 alpha = 4.12 +/- 0.25, T1/2 beta = 106 +/- 5 min; High En % HL: T1/2 alpha = 9.4 +/- 1.2, T1/2 beta = 209 +/- 5 min.
Assuntos
Harringtoninas/farmacocinética , Animais , Cromatografia Líquida de Alta Pressão/métodos , Portadores de Fármacos , Feminino , Harringtoninas/administração & dosagem , Lipossomos , Masculino , CoelhosRESUMO
Distribution of harringtonine positively and negatively charged liposome (HL(+), HL(-)) and harringtonine free drug (FH) in rat tissues were measured by HPLC. Their LD50 in mice were compared. The results showed that distribution of HL(+), HL(-), In vivo may be changed, that the amount of HL(+), HL(-) was increased in the liver, lung, and spleen and in these tissues it was 2-30-fold higher than that of HF after iv 2 h. HL(+), HL(-) may aid to permeate through the blood-brain, blood-testicle barrier, and to reduce acute lethal toxicity. Areas under the time curve of HL(+), HL(-) in brain and testis within 2 h were 2-4.5 times as much as those of HF. There were significant differences in the fate between negatively and positively charged liposomes in vivo.