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Titolo:
EFFECT OF FREEZING RATE ON THE STABILITY OF LIPOSOMES DURING FREEZE-DRYING AND REHYDRATION
Autore:
VANWINDEN ECA; ZHANG W; CROMMELIN DJA;
Indirizzi:
OCTOPLUS BV,POB 722 LEIDEN NETHERLANDS UNIV UTRECHT,UTRECHT INST DRUG EXPLORAT,UTRECHT INST PHARMACEUT SCI,DEPT PHARMACEUT NL-3508 TB UTRECHT NETHERLANDS
Titolo Testata:
Pharmaceutical research
fascicolo: 9, volume: 14, anno: 1997,
pagine: 1151 - 1160
SICI:
0724-8741(1997)14:9<1151:EOFROT>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIFFERENTIAL SCANNING CALORIMETRY; SUCROSE SOLUTIONS; FROZEN SUCROSE; STATE; VITRIFICATION; PHOSPHOLIPIDS; SACCHARIDES; TREHALOSE; SUGARS;
Keywords:
FREEZE-DRYING; LIPOSOMES; LYOPROTECTION; BILAYER TRANSITION; MODULATED TEMPERATURE DIFFERENTIAL SCANNING CALORIMETRY (MTDSC);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
E.C.A. Vanwinden et al., "EFFECT OF FREEZING RATE ON THE STABILITY OF LIPOSOMES DURING FREEZE-DRYING AND REHYDRATION", Pharmaceutical research, 14(9), 1997, pp. 1151-1160

Abstract

Purpose. In the present study we examined the effect of the freezing protocol on carboxyfluorescein (CF) retention in liposomes after freeze-drying and rehydration. Methods. Liposomes were frozen slowly at 0.5degrees C/min, or quickly by submerging the samples in boiling nitrogen before freeze-drying. The thermal behaviour of the frozen dispersions was analysed by Modulated Temperature Differential Scanning Calorimetry (MTDSC). The dried cakes were analysed by SEM, MTDSC and FTIR. The % encapsulated CF of the (re)hydrated liposomes was determined by fluorimetry after GPC, their vesicle size was measured by the Dynamic Light scattering Technique and their bilayer transition was studied by DSC. Results, Slow freezing resulted in a markedly higher CF retention after freeze-drying and rehydration as compared to quick freezing. Theeffect of the freezing rate depended on the lipid composition and wasmost pronounced for rigid liposomes. The damage caused by quick freezing did not occur after a freezing/thawing cycle. The freezing protocol did not influence the interaction between the phospholipids and the lyoprotectants (sucrose, trehalose or glucose) in the freeze-dried state. However, analysis by DSC of dipalmitoylphosphatidylcholine (DPPC):dipalmitoylphosphatidylglycerol (DPPG) = 10:1 and DPPC liposome dispersions showed that the freezing protocol affected the bilayer melting characteristics of these liposomes after freeze-drying and rehydration. Conclusions, A proper design of the freezing protocol is essential to achieve optimal stability of rigid liposomes during a freeze-drying and rehydration cycle.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/07/20 alle ore 00:55:26