Poly(alkycyanoacrylate) nanoparticles for enhanced delivery of therapeutics - is there real potential?

The properties inherent in poly(alkylcyanoacrylate) (PACA) nanoparticles, such as biocompatibility and biodegradability of the polymer, a simple preparation process and particularly the entrapment of bioactives, specifically proteins and peptides, have sparked extensive interest in these nanoparticles as drug delivery systems. Research has focused on the oral route of administration, however ocular, transdermal and delivery across the blood-brain barrier have also been investigated. Despite numerous promising studies, no formulation with this colloidal carrier has been marketed to date. A number of factors have been identified as interfering with the reproducibility of in vitro and in vivo results, which impedes the comparison of the plethora of experiments done with PACA nanoparticles. This review will highlight the challenges and opportunities of using PACA nanoparticles as drug delivery systems, including polymerisation mechanisms and templates, entrapment, release, nanoparticle uptake and toxicity. In vitro and in vivo studies, as well as possible surface modifications for targeted delivery in the human field and veterinary applications of PACA nanoparticles are reviewed. Emphasis will be placed on microemulsions as templates for the preparation of PACA nanoparticles and oral delivery of proteins and peptides.