Analysis of the Drug Release Profiles from Formulations Based on Micro and Nano Systems

The development of drug delivery systems in experimental therapy usually requires in vitro release models, that should posses specific characteristics including: low cost, simple procedure, high reproducibility and very importantly resemble as strictly as possible the in vivo behaviour. In this respect, the paper describes the effects of the use of different experimental procedures on the drug release profiles from controlled delivery formulations based on nano and micro systems. As examples of micro and nanosystems, microparticles constituted of poly-lactide-co-glycolide (PEM) or gelatine (GEM) and nanostructured lipid carriers (NLC) or cubosomes (CBS) were selected, respectively. All the analysed formulations contained bromocriptine (BC) that represents a poorly water-soluble drug. The influence of the experimental release method and of release media has been investigated using different experimental set-up including direct and reverse dialysis, flow-through cell, USP XXII paddle and Franz cell methods.