NOTE
Kinetics of Destabilization of Calcitonin Monolayers at the Air/Water Interface interface by measuring the area loss at different surface pressures and various temperatures as well as pH values of the subphase. Monolayer behavior and desorption of calcitonin molecules from Salmon calcitonin, supplied by Sandoz Laboratories (Basilea) was used the air/water interface under constant surface pressure were invesas experimental material. All solvents used (p.a.) were purchased from tigated. The change of area with time for one molecule in the Merck. monolayer was recorded under different temperatures and pH Calcitonin was dissolved in 4:1 (v/v) chloroform-methanol solution.
values of the subphase. The desorption of calcitonin occurs only in To facilitate spreading, 0.5% (v/v) of amyl alcohol was added. Such a the plateau region and increases with decreased pH and increased composition of solvents was found to be the best for obtaining a well- temperature. The desorption process was found to be diffusion spread monolayer of calcitonin at the water/air interface (6). controlled. Applying the Ter Minassian Saraga model (J. Chem.
Surface pressure/area (p/A) isotherms were recorded on compression Phys. 52, 181 (1955)), the kinetic parameters corresponding to using a Langmuir film balance (FW-1 Lauda, Germany) at a rate of 0.11 the desorption and diffusion were estimated. ᭧ 1998 Academic Press cm/s. Preliminary experiments proved that the isotherms were identical to those obtained at such a low speed as 0.044 cm/s.