ABSTRACT
The complementary mixing and de-mixing of phases is seen as a methodology for use in 'smart' drug delivery systems. Surface tensions were routinely lowered to 50-55 mN/m in drug mixtures and this is compared to low molecular weight emulsifiers such as Tween 80. In the research reported here, mixing of a heterocyclic drug and an amphiphilic polymer is responsible for structural inconsistency at the air-water (A/W) interface and presents itself as a means of release of drug from a series of complex drug formulations. The work was extended to look at the behavior of both "soft" and "hard" particle hydrophobic and hydrophilic particle stabilization of emulsions of 20 and 0.7 µm. The work is based on spread interfacial monolayers, thin liquid films emulsion droplets and model latex nanoparticle beads (60 and 500 nm) in the presence and absence of poloxamer (Pluronic) and methotrexate. The interfacial rheological characteristics and AFM-based nano-rheology were used to aid the elucidation of surface structure and nano-architectures within the plane of the adsorbed interfacial layer and for use in the fabrication of solid nano-particle stabilized micron and nano-sized oil-inwater (O/W) emulsions.
