Preparation of calcium chloride-loaded solid lipid particles and heat-triggered calcium ion release

초록

CaCl2-loaded solid lipid particles (SLPs) were prepared by a melt/emulsification/solidification method. CaCl2 microparticles (1-5 mu m) could be obtained in a mortar with aid of the dispersant (Tween 80/Span80 (35/65, w/w)) when the ratio of CaCl2 to dispersant was 2: 0.1 (w/w). SLP was prepared by dispersing 0.42 g of micronized CaCl2 particles in 2 g of molten PBSA, emulsifying the mixture at 85 A degrees C in 40 ml of Tween 20 solution (0.5% w/v), and quenching the emulsion in an ice bath. The diameter of CaCl2-loaded SLP was 10-150 mu m. The unenveloped CaCl2 could be removed by dialysis and the specific loading of CaCl2 in SLP was 0.036mg/mg. An EDS spectrum of CaCl2-loaded SLP, which was dialyzed, showed that the unenveloped CaCl2 was completely removed. Any excipients (dispersant, Tween 20, CaCl2) had little effect on the melting point of SLPs. No appreciable amount of Ca2+ was released in 20-50 A degrees C for 22 h. But the release degree at 60 A degrees C was significant (about 2.3%) during the same period. The matrix of the lipid particle was in a liquid state at 60 A degrees C, so CaCl2 particles could move freely and contact the surrounding water, leading to the release. At 70 A degrees C, the release degree at a given time was a few times higher than that obtained at 60 degrees C.

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