Remote Loading Of Tretinoin Into Liposome Gel By Calcium Acetate Gradient Method

In this paper, a novel procedure to load the tretinoin into liposome gel was described. This liposome prepared by calcium acetate gradient method with more effective,more entrapped efficiency(EE),more bioavailability and fewer adverse reactions and irritation comparing to other transdermal preparations.The EE of drug was determined spectrophotometrically by Ultraviolet absorbance at 351nm after the free drug molecules was separated from tretinoin liposome on a sephadexG-50 minicolumn. We studied the mechanic and influencing factors of EE followed these aspects: the concentration of calcium acetate,incubation time and temperature,EPC:Ch and drug to phospholipid. Compared to the passive loading methods, the calcium acetate gradient method had the highest EE of 90.48%. And the passive loading methods just had 20.17% and 21.68%.High pressure homogeneous method was used in preparating tretinoin liposome by homogenizing 3 times at 12000 bar pressure. Zetasizer 3000 and electroscopy were applied to determine the size of tretinoin liposome. The liposomes had perfect shape with the mean diameter of 80.8nm.