Nanospheres and nanocapsules of β-CDC6, amphiphilic β-cyclodextrin modified on the secondary face with 6C aliphatic esters, were prepared with nanoprecipitation technique directly from inclusion complexes of tamoxifen citrate and β-CDC6 (1:1 molar ratio). Blank and loaded nanospheres and nanocapsules were characterized by particle size distribution, zeta potential, drug loading and in vitro drug release. Particle sizes were between 250 and 300 nm for different formulations of nanospheres and nanocapsules. Zeta potential which was around −18 mV for blank particles was reported to be between +12 and +15 mV for tamoxifen-loaded particles. Average entrapped drug quantity was found to be around 150 μg/mL for particles prepared from inclusion complexes and this is double the loading value for conventionally prepared particles. Pre-loaded formulations showed a significantly slower release profile extended up to 6 h while formulations loaded conventionally displayed rapid and complete release within an hour. Cytotoxic efficacy of tamoxifen citrate loaded nanospheres and nanocapsules was determined against MCF-7 cells and tamoxifen citrate incorporated in amphiphilic β-cyclodextrin nanoparticles was found to be cytotoxic and effective against this cell line.