Phase behaviour of transkarbam 12.
Transkarbam 12 (T12), the carbamic acid salt of omega-aminocaproic acid dodecyl ester, is a recently synthesized substance, whose high permeation enhancing activity through the human skin was found for certain drugs. In this work, the thermotropic phase behaviour of T12 has been studied by means of various techniques, namely, DSC, FTIR and FT-Raman spectroscopy, X-ray powder diffraction, and DRS. The temperature development of the X-ray reflections as well as of the conformationally sensitive Raman bands and the IR bands have been observed. At room temperature, the hydrocarbon chains of T12 exhibit a highly ordered structure, arranged in an orthorhombic perpendicular subcell. On heating, two transitions occur at 54 and at 66 degrees C. The first transition is related to the disruption of the carbamate structure and changes in the polar head group. The other transition represents the melting of hydrocarbon chains and the subsequent release of carbon dioxide. The time required for the rebinding of carbon dioxide and the reformation of the carbamate structure is dependent upon numerous factors and it was not possible to precisely determine the length of this process.
Faculty of Pharmacy, Charles University, Heyrovského 1203, 50005 Hradec Králové, Czech Republic.
Jarmila
J
Zbytovská
Steve
S
Raudenkolb
Siegfried
S
Wartewig
Wigand
W
Hübner
Willi
W
Rettig
Polycarpos
P
Pissis
Alexandr
A
Hrabálek
Pavel
P
Dolezal
Reinhard H H
RH
Neubert
D000614:Aminocaproates; D015119:Aminocaproic Acid / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002219:Carbamates / Q000737:chemistry*; D007851:Dodecanol / Q000737:chemistry; D006801:Humans; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D013696:Temperature; D014961:X-Ray Diffraction
D000614:Aminocaproates; D002219:Carbamates; C492029:transkarbam 12; D007851:Dodecanol; D015119:Aminocaproic Acid