Fig. 2.

Elution profile (size-exclusion chromatography columns) of alendronate liposomes as function of size (diameter, left column), alendronate concentration (middle column), and lipid concentration (right column) in specimens recovered over time following incubation in rabbit’s serum in vitro, a alendronate liposomes (611 μg/ml), b empty liposomes spiked with alendronate (611 μg/ml), c empty liposomes, and d free alendronate (611 μg/ml). In this system of size-exclusion chromatography, intact liposomes are detected in fractions 1 to 3, fraction 4 is a transitional phase, and free drug is detected in fractions 5–10 (total of 20 fractions, 2 ml each). Background noise, obtained from the elution’s profile of serum incubated with buffer at the same volumes ratio, was subtracted