Copper phthalocyanine labelled magnetic microcapsules: preparation, and binding properties in vitro and in vivo for...

Copper phthalocyanine tetrasulphonic acid (CPTS) functions were introduced into magnetic semi-permeable polyethyleneimine (PEI) microcapsules in order to create a recoverable scavenging system for trapping and biomonitoring, within the gastrointestinal cavity, of mutagens having a planar molecular structure. Stable ionic CPTS and covalent (thionylated CPTS, TCPTS) adducts to the microcapsule PEI were produced and shown to trap benzo[a]pyrene (B[a]P) in vitro in relation to the porphyrin/B[a]P ratio employed. 3-hydroxy B[a]P and B[a]P 3,6-dione from a crude B[a]P metabolite mixture, and a set of planar mutagens from crude opium/morphine pyrolysate mixtures could also be recovered in 7-86% yields after shaking with modified microcapsules followed by methanol/ammonia (50:1) desorption. Tetraols derived from B[a]P 7,8-diol-9,10 epoxide could also be recovered. Modified microcapsules were recovered magnetically from faeces of rats treated with [14C]B[a]P, and 45-51% of trapped radioactivity could be directly desorbed for HPLC assay compared with 30% for unmodified microscapsules. The relative extent of trapping by unmodified or CPTS- or TCPTS-modified microcapsules was different for various substrates, and it appears that the copper phthalocyanine tetrasulphonic acid moiety competes with another unidentified absorption/desorption structure in the microcapsules. These results show that selective and reversible trapping of carcinogens/mutagens having planar molecular structure can be achieved within the gastrointestinal tract.