Abstract
To develop microparticulate drug delivery system, numerous approaches have been tried to optimize the drug delivery. In this review, functional design of microparticlate drug delivery systems by controlling the particle size are focused. The particle size affect biodistribution after i. v. administration, drug release rate, bioavailability through the mucus layer via oral, nasal and pulmonary administration, Among the characteristic functions of nano-and micro-spheres, the ability to deliver the drug across a number of biological barriers to the target site is attractive for drug carriers. The mucosal delivery of high molecular weight substances, such as peptides, proteins, oligonucleotides and plasmids using nanoparticulate systems are discussed in the view of challenges for drug and gene targeting. Lymphatic targeting of drugs has been achieved with nanospheres with a suitable size distribution and appropriate surface characteristics to enhance the accumulation of drug in the lymph nodes following oral administration, In addition to the intestinal mucosal transportation of particles, the particle transfer across nasal and pulmonary mucosa is also discussed.
