Microbiological and densitometric TLC analyses for peptides in liposomes

Quantitative determination of Leucinostatins and/or of similar peptides, su ch as Peptaibols, is sometimes quite difficult to perform especially when t hey are entrapped in vectors, i.e. liposomes, whose components display UV a bsorbances that may obscure those of the active: principle. Therefore, in t hese cases, it is useful to find alternative ways, especially when high pre ssure liquid chromatography (HPLC) is difficult to perform or needs long pr ocedure times. In the present paper, the use of microbiological and densito metric methods for quantitative analysis of Leucinostatin A (Leu-A) are des cribed and the results compared with those from HPLC analyses, The use of m icrobiological and densitometric assays, furnished results comparable with those obtained by HPLC. Of the two methods used, the microbiological proced ure appeared to be less accurate and precise. (C) 2001 Elsevier Science B.V . All rights reserved.