How subtle differences in polymer molecular weight affect doxorubicin-loaded PLGA nanoparticles degradation and drug release

Abstract

<b>Aims:</b> To evaluate the influence of minor differences in molecular weights of commercially available low molecular weight PLGA grades on the kinetics of doxorubicin release from the nanoparticles.<b>Methods:</b> Three low-molecular weight 50/50 PLGA polymers were thoroughly characterised concerning intrinsic viscosity, molecular weight (Mw), acid value, and residual monomer content. The doxorubicin-loaded nanoparticles prepared using these polymers were evaluated concerning the kinetics of drug release and hydrolytic degradation.<b>Results:</b> The Mw of the polymers were slightly different: 10.2, 10.3, and 4.7 kDa. The nanoparticles obtained from the polymer with Mw of 4.7 kDa exhibited considerably higher rates of drug release and polymer degradation.<b>Conclusion:</b> In the case of low molecular weight PLGA grades even a few kilodaltons could be important for the batch-to-batch reproducibility of the nanoformulation parameters. These results bring forward the importance of in-house characterisation of the polymers to be used for the nanoparticle preparation.