ABSTRACT
This chapter discusses several issues related to the carboxyfluorescein (CF) assay, as experienced in the laboratory. It describes a simple, one-step purification method for CF. The chapter outlines several important experimental details in handling liposomes when measuring their stability, especially in the presence of human serum, e.g., efficient separation of CF-containing liposomes from free CF by the minicolumn-centrifugation technique, the effects of centrifugation on liposome stability, and problems when determining the total amount of liposome-contained CF. It shows that critically the advantages and the limitations of this technique when measuring under the proper working conditions liposome stability in vitro and in vivo. In 1977 J. N. Weinstein and co-workers introduced a simple fluorescent method to measure the movements of a liposome entrapped fluorescent marker, CF across the bilayer membranes. At various stages in the course of CF-release experiments, the liposomes are subjected to mechanical forces which arc sufficient to impair their stability.
