Drug release study of large hollow nanoparticulate aggregates carrier particles for pulmonary delivery.

The aim of the present work is to examine the viability of using large hollow nanoparticulate aggregates as the therapeutic carrier particles in dry powder inhaler delivery of nanoparticulate drugs. The large hollow carrier particles are manufactured by spray drying of nanoparticulate suspensions of biocompatible acrylic polymer with loaded drugs. The size and concentration of the nanoparticles, as well as the phospholipids inclusion, have been known to influence the resulting morphology (i.e. size and degree of hollowness) of the spray-dried carrier particles. The effects of the resulting morphology of the carrier particles on the drug release rate are therefore investigated by varying the above three variables. The results of the drug release study are presented using aspirin and salbutamol sulfate as the model drugs with a varying degree of water solubility. The results indicate that the drug release rate is governed by the degree of hollowness of the carrier particles, and to a lesser extent by the nanoparticles size, as a result of the variation in the drug loading capacity of nanoparticles of different sizes.