title: Delivery of an anticancer drug and a chemosensitizer to murine breast sarcoma by intratumoral injection of sulfopropyl dextran microspheres.
abstract: Intratumoral injection of controlled-release microsphere formulations of anticancer compounds has the potential to selectively increase tumour exposure to drugs. This work aimed to evaluate the therapeutic effect and toxicity of microsphere formulations containing the anticancer drug, doxorubicin, in a murine tumour model. The effect of co-administration of verapamil, a P-glycoprotein modulator or chemosensitizer, was investigated. Initial in-vitro studies confirmed the ability of verapamil to enhance the accumulation of both doxorubicin and [(99mTc)]sestamibi, also a P-glycoprotein substrate, in EMT6 murine breast sarcoma cells and a doxorubicin-selected multidrug-resistant variant, EMT6/AR1.0. Ex-vivo studies using confocal microscopy demonstrated release of doxorubicin from microspheres and diffusion of the drug through tissue. For in-vivo studies, EMT6 and EMT6/AR1.0 cells were grown in BALB/c mice. Following intratumoral injection of doxorubicin-loaded microspheres, alone or in combination with verapamil-loaded microspheres, the tumour diameter was measured serially as an indication of therapeutic effect, while the weight, appearance, and behaviour of the mice were monitored as an indication of general toxicity. Intratumoral injections of doxorubicin-loaded microspheres were tolerated much better than systemic administration of equivalent drug concentrations. There was a modest (up to 34%) delay of tumour growth compared with groups receiving no treatment or blank microspheres. Co-injection of verapamil microspheres with doxorubicin microspheres produced a moderate increase in toxicity but no further delay in tumour growth. Controlled-release microsphere formulations of anticancer agents administered intratumorally were an efficient way to deliver high drug doses to the tumour with little systemic toxicity.
authors.affiliation: Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 2S2, Canada.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liu
authors.forename: James R
authors.initials: JR
authors.lastname: Ballinger
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Rauth
authors.forename: Reina
authors.initials: R
authors.lastname: Bendayan
authors.forename: Xiao Yu
authors.initials: XY
authors.lastname: Wu
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003692:Delayed-Action Preparations; D003911:Dextrans / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D005260:Female; D019450:Genes, MDR / Q000235:genetics; D007267:Injections; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008863:Microspheres; D012513:Sarcoma, Experimental / Q000188:drug therapy*; D014700:Verapamil / Q000008:administration & dosage* / Q000493:pharmacokinetics
chemical_list: D003692:Delayed-Action Preparations; D003911:Dextrans; D004317:Doxorubicin; D014700:Verapamil