The polyion complex nano-prodrug of doxorubicin (DOX) with poly(lactic acid-co-malic acid)-block-polyethylene glycol: preparation and drug controlled release

A polyion complex nano-prodrug based on the complexation of the ionomer of poly(lactic acid-co-malic acid)-block-polyethylene glycol [Poly(LA-co-MA)-b-PEG] with doxorubicin (DOX) was developed. The ionomer was prepared by a direct polycondensation of d,l-lactic acid (LA), l-malic acid (MA), and monomethyl polyethylene glycol (PEG) using stannous chloride (SnCl2) as the catalyst. The nanoparticles were formed through electrostatic interactions between the side carboxyl groups of MA units in the ionomer and amino groups of DOX. The nanoparticle possessed an amphiphilic structure with a hydrophobic core of the complexed DOX and Poly(LA-co-MA) and a hydrophilic shell of PEG. The nanoparticle solution was stable, and the particle sizes were in the range of 110–140 nm. The DOX was loaded as a prodrug with loading rate as high as 18.2 %. The drug release could be controlled, showing responsiveness of acids and ionic strength. The cumulative release was as high as 94 %. The nanoparticles could be potentially used as anti-cancer drug vehicles.