title: Fabrication of doxorubicin nanoparticles by controlled antisolvent precipitation for enhanced intracellular delivery.
abstract: Over-expression of ATP-binding cassette transporters is one of the most important mechanisms responsible for multidrug resistance. Here, we aimed to develop a stable polymeric nanoparticle system by flash nanoprecipitation (FNP) for enhanced anticancer drug delivery into drug resistant cancer cells. As an antisolvent precipitation process, FNP works best for highly lipophilic solutes (logP>6). Thus we also aimed to evaluate the applicability of FNP to drugs with relatively low lipophilicity (logP=1-2). To this end, doxorubicin (DOX), an anthracycline anticancer agent and a P-gp substrate with a logP of 1.3, was selected as a model drug for the assessment. DOX was successfully incorporated into the amphiphilic diblock copolymer, polyethylene glycol-b-polylactic acid (PEG-b-PLA), by FNP using a four-stream multi-inlet vortex mixer. Optimization of key processing parameters and co-formulation with the co-stabilizer, polyvinylpyrrolidone, yielded highly stable, roughly spherical DOX-loaded PEG-b-PLA nanoparticles (DOX.NP) with mean particle size below 100nm, drug loading up to 14%, and drug encapsulation efficiency up to 49%. DOX.NP exhibited a pH-dependent drug release profile with higher cumulative release rate at acidic pHs. Surface analysis of DOX.NP by XPS revealed an absence of DOX on the particle surface, indicative of complete drug encapsulation. While there were no significant differences in cytotoxic effect on P-gp over-expressing LCC6/MDR cell line between DOX.NP and free DOX in buffered aqueous media, DOX.NP exhibited a considerably higher cellular uptake and intracellular retention after efflux. The apparent lack of cytotoxicity enhancement with DOX.NP may be attributable to its slow DOX release inside the cells.
authors.affiliation: School of Pharmacy, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
authors.forename: Yu Tong
authors.initials: YT
authors.lastname: Tam
authors.affiliation: School of Pharmacy, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
authors.forename: Kenneth Kin Wah
authors.initials: KK
authors.lastname: To
authors.affiliation: School of Pharmacy, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong. Electronic address: albert-chow@cuhk.edu.hk.
authors.forename: Albert Hee Lum
authors.initials: AH
authors.lastname: Chow
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism; D000903:Antibiotics, Antineoplastic / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D011232:Chemical Precipitation; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D065546:Drug Liberation; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D007773:Lactates / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D011205:Povidone / Q000737:chemistry
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D004337:Drug Carriers; D007773:Lactates; C088513:poly(lactic acid-ethylene glycol); D011092:Polyethylene Glycols; D004317:Doxorubicin; D011205:Povidone
keywords: Amphiphilic diblock copolymer; Anticancer activity; Flash nanoprecipitation; Lipophilicity; Multidrug resistance; Polymer-stabilized doxorubicin nanoparticles; Polyvinylpyrrolidone; Slow release; Stability