Stability and CMC determinations of amphiphilic (DSPEPEG(3400)-CTT2) peptide constructs by microtensiometry

Controlled formation and stability of micelles and micellar properties are crucial in ensuring pharmaceutical and physiological efficiency of drug targeting/delivering constructs. In this study, the formulative properties of a polymeric, micelle forming, pegylated cancer targeting peptide, DSPE-PEG(3400)-CTT2, were determined in a 96-well plate. A microtensiometer was used to determine the critical micelle concentration (CMC) and micelle formation of the peptide derivative in different aqueous solutions. Particle size and size distribution were measured by dynamic light scattering. The CMC values of DSPE-PEG(3400)-CTT2 were at micrograms in milliliter level. The media exerted clear effects on the CMC values and formation of micelles. Partitioning coefficient, Kaw, values in the acidic media were higher than in pure water, which means that the micellar associates are formed at a lower concentration in an acidic environment. The areas per molecule were also dependent on the medium. Micellar sizes were 18–22 nm in all the media. Accordingly, stability of micellar formulations is highly dependent on the environmental factors.