title: Tracer microspheres as compliance markers in clinical research.
abstract: Tracer microspheres are small, ceramic-like particles (50 micron) containing one of several radionuclide markers. We have utilized them over a period of 9 years as quantitative fecal markers for recovery measurements in metabolic studies. The markers have been administered daily for up to 2 weeks, during which time the marker concentration per unit dry weight of feces remains fairly constant. Data on the markers and our experience with them are presented along with the concerns that must be addressed in considering them as compliance markers.
mesh_terms: D002986:Clinical Trials as Topic; D005243:Feces / Q000032:analysis; D006801:Humans; D007408:Intestinal Absorption; D008863:Microspheres; D010316:Particle Size; D010349:Patient Compliance; D004364:Pharmaceutical Preparations / Q000378:metabolism; D011137:Polystyrenes; D013997:Time Factors
chemical_list: D004364:Pharmaceutical Preparations; D011137:Polystyrenes