In-vivo evaluation of tamoxifen-loaded microspheres based on mixtures of poly (D,L-lactide-co-glycolide)and poly (D,L-lactide) polymers

Abstract

Microspheres of different proportions of poly-(D,L-lactideco-glycolide) and poly-(D,L-lactide) were formulated by spray drying as a drug-delivery system for the treatment of breast cancer with tamoxifen. These systems had been evaluated previously in vitro and showed very positive results that have led to further assessment in vivo. This work evaluates the performance of these systems in an organism by carrying out a study in female Wistar rats. Microspheres were subcutaneously injected into the back of rats for the assessment of not only the biocompatibility but also the release of the drug contained and its biodistribution. As, in vitro, these systems could release the drug under physiological conditions; different plasma concentrations of tamoxifen and one of its metabolites, 4-hydroxy-tamoxifen, were achieved depending on the polymer composition. Microspheres could reduce the accumulation of the drug in different nontarget organs and presented good biocompatibility.