Phase Transitions in the Lyotropic System Dipalmitoyl Phosphatidyl Choline (DPPC) Doped with the Antileprosy Drug, Dapsone

Nuclear magnetic resonance and thermal studies of drug doped dipalmitoyl phosphatidyl choline-H2O systems

“…DMS being more polar than DDS, is less likely to enter the acyl chain region. However, it must be decreasing slightly, the effective interaction between DPPC head groups, leading to the observed decrease in T CM• The values of Tcm and ∆H CM measured with stacked bilayers (Deniz et al, 1983) 5)-( 7) are clearly visible at 315 K. The chain resonances are seen to be very broad and unresolved at 310 and 312 K. They begin to get resolved at 313 K, showing that 312 K<T CM < 313 K. The N + (CH 3 ) 3 resonance, ( 5) is sharp even at 310 K, indicating that these methyl groups are quite mobile not only for T>T CM but also for T<T CM Resonance (5) consists of two peaks, (5)' and ( 5)" corresponding to the choline groups of the outer and inner leaflets of the bilayer.…”

“…These drugs are expected to possess distorted tetrahedral structures (figure 1). Though DDS has been in use as an antileprosy drug for a few decades, hardly any information about its interactions with membranes was available until recently (Deniz et al, 1983(Deniz et al, , 1989. While our main interest was in DDS-membrane interactions, DMS was used in order to understand how structural differences affect these interactions.…”