Factors involved in the production of liposomes with a high-pressure homogenizer

A variety of factors were evaluated in order to establish the characteristi cs of the liposomes obtained with a high-pressure homogenizer (Microfluidiz er 110S). The experimental mean diameter of the liposomes and the width of their size distribution were correlated to surfaces calculated from the res ponses obtained by the combination of two groups of factors. First, the inl et pressure of the homogenizer, the times that the samples were processed ( cycles) and the bulk ionic strength. Second, the phospholipid (P) and ethan ol concentrations. The variation of the entrapped liposome volume upon the pressure and cycles was also studied. All the calculated surfaces are stati stically significant and have a low S.E. of estimate. Mean liposome diamete r decreases with increasing inlet pressure: number of cycles and ethanol co ncentration, and increases raising ionic strength. No P concentration effec t was observed. The variation of the entrapped volume of liposomes upon the cycles and pressure has a Similar behavior to the diameter. Within the stu died variable range, microfluidization does not increase the P oxidation in dex, nor does it significantly alter the P concentration. (C) 2001 Elsevier Science B.V. All rights reserved.