Controlled release of 4-nitroanisole from poly(lactic acid) nanoparticles.

The controlled release of 4-nitroanisole from polylactide nanoparticles with different morphologies is reported. Two theoretical equations have been used in an attempt to fit the experimental results. Good agreement between theory and experiment was found for short release time. The estimated values of the diffusion coefficient of 4-nitroanisole in these nanoparticles, at short times (up to 50% release), were all approximately 10(-19) m(2)s(-1). At long time some differences in release behaviour were observed for different morphologies.