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Stability and narrow size distribution are among the main requirements that apply to drug formulations based on polymeric nanoparticles. In this study, we obtained a series of particles based on biodegradable poly(D,L-lactide)-b-poly(ethylene glycol) (P(D,L)LAn-b-PEG113) copolymers with varied hydrophobic P(D,L)LA block length n from 50 to 1230 monomer units stabilized by poly(vinyl alcohol) (PVA) by a simple "oil-in-water" emulsion method. We found that nanoparticles of P(D,L)LAn-b-PEG113 copolymers with relatively short P(D,L)LA block (n ≤ 180) are prone to aggregate in water. P(D,L)LAn-b-PEG113 copolymers with n ≥ 680 can form spherical unimodal particles with values of hydrodynamic diameter less than 250 nm and polydispersity less than 0.2. The aggregation behavior of P(D,L)LAn-b-PEG113 particles was elucidated in terms of tethering density and conformation of PEG chains at the P(D,L)LA core. Docetaxel (DTX) loaded nanoparticles based on P(D,L)LA680-b-PEG113 and P(D,L)LA1230-b-PEG113 copolymers were formulated and studied. It was observed that DTX-loaded P(D,L)LAn-b-PEG113 (n = 680, 1230) particles are characterized by high thermodynamic and kinetic stability in aqueous medium. The cumulative release of DTX from the P(D,L)LAn-b-PEG113 (n = 680, 1230) particles is sustained. An increase in P(D,L)LA block length results in a decrease in DTX release rate. The in vitro antiproliferative activity and selectivity studies revealed that DTX-loaded P(D,L)LA1230-b-PEG113 nanoparticles demonstrate better anticancer performance than free DTX. Favorable freeze-drying conditions for DTX nanoformulation based on P(D,L)LA1230-b-PEG113 particles were also established. [ABSTRACT FROM AUTHOR]

[Display omitted] The effect of crystallization of a hydrophobic poly(lactide) block on the self-organization of biocompatible and biodegradable amphiphilic poly(lactide)- block -poly(ethylene oxide) (PLA- b -PEO) copolymers in a dilute aqueous solution has been investigated. It was demonstrated that the co-crystallization of poly(L,L-lactide) [P(L,L)LA] and poly(d,d-lactide) [P(d,d)LA] chains under equimolar mixing of P(L,L)LA 46 - b -PEO 113 and P(d,d)LA 56 - b -PEO 113 copolymers resulted in the formation of stable and spontaneously water-redispersible stereocomplex micelles with semicrystalline P(L,L)LA/P(d,d)LA cores. It was shown that the P(L,L)LA 46 / P(d,d)LA 56 - b -PEO 113 stereo-complex micelles produced by dialysis can be potential vehicles for the anticancer agent oxaliplatin [ABSTRACT FROM AUTHOR]