title: Effect of particle size of nanospheres and microspheres on the cellular-association and cytotoxicity of paclitaxel in 4T1 cells.
abstract: OBJECTIVE
  To compare the effect of size of delivery systems on the cell-association and in vitro cytotoxicity of paclitaxel.
  
  
  METHODS
  Four sizes of PLGA-paclitaxel particles were prepared to study the effect of particle size on the cell-association of paclitaxel in 4T1 monolayer in the presence, and absence, of BCRP inhibitor, endocytic inhibitor, and P-glycoprotein (P-gp) inhibitor. Paclitaxel cell-association studies were repeated in Caco-2, Cor-L23/R, and bovine brain microvessel endothelial cells (BBMECs), as well as the association of etoposide in 4T1 cells. Cytotoxicity of paclitaxel to 4T1 cells delivered in nanospheres was compared to microspheres.
  
  
  RESULTS
  The concentration of paclitaxel and etoposide associated with 4T1 cells was 4.8 and 29 times greater, respectively, as the size increased from 310 to 2077 nm. Paclitaxel association consistently increased in Caco-2 and Cor-L23/R as the size of the delivery system increased. The endocytic inhibitor, 2-deoxyglucose, significantly decreased the cellular paclitaxel association when delivered by nanospheres but not microspheres. Consistent with the cell-association results, paclitaxel was thrice more cytotoxic to 4T1 cells when delivered in microspheres.
  
  
  CONCLUSIONS
  Cell-association of paclitaxel increased in 4T1, Caco-2, and Cor-L23/R as particle size increased. Paclitaxel delivered from 1-mum microspheres was thrice more cytotoxic to 4T1 cells compared to the drug delivered from nanospheres or solution.
authors.affiliation: College of Pharmacy, Ohio Northern University, Ada, Ohio, USA.
authors.forename: Sinjan
authors.initials: S
authors.lastname: De
authors.forename: Donald W
authors.initials: DW
authors.lastname: Miller
authors.forename: Dennis H
authors.initials: DH
authors.lastname: Robinson
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000818:Animals; D001896:Boron Compounds / Q000737:chemistry / Q000494:pharmacology; D001921:Brain / Q000098:blood supply / Q000187:drug effects / Q000473:pathology; D002417:Cattle; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D002626:Chemistry, Pharmaceutical / Q000379:methods; D016572:Cyclosporine / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D004705:Endocytosis / Q000187:drug effects; D004730:Endothelium, Vascular / Q000187:drug effects / Q000473:pathology; D005047:Etoposide / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D019344:Lactic Acid / Q000737:chemistry / Q000494:pharmacology; D008863:Microspheres; D043942:Nanotubes / Q000737:chemistry*; D017239:Paclitaxel / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics*; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry / Q000494:pharmacology; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D018435:ATP Binding Cassette Transporter, Subfamily B; D001896:Boron Compounds; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D005047:Etoposide; D016572:Cyclosporine; D003847:Deoxyglucose; D017239:Paclitaxel