Interdigitated liposomes

Vesicles in the size range from 0.5 to several micrometers can be prepared by other methods, such as detergent or other agent induced fusion, freeze-thaw cycles, the cochleate cylinder method, and the fusion of large interdigitated liposomes [14]. 

Several other examples of drug-membrane interactions have been reported. Using X-ray diffraction techniques, interactions with tetracyclines [75], pindolol [76], and chlorpromazine [77, 78] have been described. In these studies, it was shown that in the presence of chlorpromazine the bilayer thickness or lipid head group separation in DPPC liposomes is only 30 A, which is about 20 A smaller than two fully extended DPPC molecules. Chlorpromazine produced an interdigitated phase, which is in agreement with the observed effect of chlorpromazine on the shape of erythrocytes. 

DSC provides useful information in the design of liposomal formulations for incorporating labdanes while phenomena like interdigitation should be taken into account when designing lipid carriers. It is obvious from the above paradigms that bioactivc natural compounds can demonstrate improved pharmacological responses and their biodistribution and pharmacokinetic profiles can be controlled by designing suitable carrier for each compound. 

About 50-100 pi of giant liposome suspension was introduced into a microscope chamber, the bottom of which supports a pattern of interdigital gold electrodes [11]. The distance between the electrodes was 200 pm. A cover slip was placed over the giant liposome suspension. Individual giant liposomes were clearly visible through the glass chamber. 

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