A study of the stability of amphotericin B monolayers

Desorption of Amphotericin B from Mixed Monolayers with Cholesterol at the Air/Water Interface

“…Nevertheless, the overall behavior is similar and for a detailed analysis of the mixed Langmuir isotherms the readers are referred to our previous papers (4,6). The relaxation experiments carried out for the AmB monolayer alone (9) confirm that amphotericin molecules undergo desorption from the surface. The process was found to follow the mechanism of Ter Minassian Saraga (10) for monolayers formed by molecules which are slightly soluble in water.…”

“…The extent of AmB loss from the monolayer was found to depend on both the surface pressure (increases with increasing surface pressure) and the ionic strength of the subphase (decreases with NaCl added) (9). The relaxation experiments have confirmed that AmB in its horizontal position (preplateau region) is more stable than that oriented vertically (postplateau).…”

“…10 mN/m), the desorption kinetics for the mixture of X AmB = 0.1 was not studied. It is to be reminded here that for the monolayers of AmB alone, at low surface pressures, the loss of molecules from the surface was found to be controlled first by dissolution (at small times) and then by diffusion (9). Thus, the whole process obeys the Ter Minassian Saraga model (Eqs.…”

“…This fact, together with the very small value of area extrapolated from the straight line of the isotherm above the transition (27Å 2 /molecule) in comparison to the geometrical cross-sectional area of vertically oriented molecule (55Å 2 ) (8), suggested the loss of AmB molecules from the surface. The desorption of amphotericin from the monolayer at high surface pressures was later evidenced by the relaxation experiments involving measurements of the decrease in area per molecule at a constant surface pressure (9). Interestingly, when AmB was mixed with a sterol, the stability of the monolayer was increased, implying complex formation with 2 : 1 stoichiometry (4-7), the structure of which is presented in Ref.…”

Interactions of amphotericin B derivative of low toxicity with biological membrane components—the Langmuir monolayer approach

“…On the other hand, the characteristic feature of the pressure/area (p/A) isotherm of the parent, unsubstituted AmB is a transition plateau that separates two regions of liquid-expanded (LE) and liquid-condensed (LC) state [46]. It has been supposed [22,47] that in the liquid-expanded region, molecules are lying flat on the surface (with the limiting area of ca.…”