A study of photochromic azobenzene liquid crystals as controlled release drug delivery systems

Photochemically induced liquid crystal phase transitions are considered in the context of photo-induced controlled drug release. The model materials e xamined are the homologous series of 4-n-butyl-4'-n-alkoxyazobenzenes (BAAB s). Radiation from a low power argon ion laser is used to induce the photoc hromic trans-cia isomerisation of the materials, resulting in an isothermal phase transition from the nematic to the isotropic phase. The response tim es are examined with respect to temperature, cell thickness and homologue. The data are discussed in the context of such systems' usefulness and ultim ate applicability in photo-responsive drug delivery devices.