Abstract:
The polyphase liposome (139) was made of soybean lecithin, cholesterol, tween, span, PVP and a vegetable constituent. Its technological characteristics were investigated by means of
1HNMR at different temperatures. It was found that two distinct high resonances for—CH
3(0.88) and—(CH
2)
n—(1.27)appeareal from 78° to 90℃ in the upfield region of the
1HNMR spectrum of liposomes in deuterowater. This shows that the liposome preparation produces phase change at temperatures above 78℃. However, when the preparation was cooled to room temperature, the spectrum returned to its original pattern. So the injectable preparation may be subjected to steam sterilization for large scale production.The addition of amphipathic compounds broadened the resonances of terminal methyl group, methylene group and headgroup of lecithin. When
13CNMR spectra cf polyphase liposome (139) were observed, we found that the relaxation time of
13carbon nuclei T
1 increased along the alkyl chains towards the terminal methyl group. When comparisons were made between liposomes and lecithin, a smaller T
1 value of the terminal methyl group and a larger T
1 value of—N(CH
3)
3 group were obtained for the former. This indicates that the terminal methyl group is less mobile and the—N(CH
3)
3 group has a higher degree of mobility compared with the lecithin in H
2OAll the measurements were performed on Jeol-FX60 QNMR.