P. Muthu Prasanna

  The Pulmonary route has been conventionally used to treat diseases of the respiratory tract and also non-respiratory tract. The significant research work from the last two decades have exposed that in addition to treating local diseases, a wide range of systemic diseases can be treated by delivering drugs to the lungs. In general inhalable formulations of various drugs have been developed to treat the systemic diseases via the lungs. But the problem with those inhalable formulations is they need repeated doses of drug to control the disease condition, since the inhaled drug cleared rapidly. Therefore new technologies have been investigated, where inhaled particles are capable of controlled release of drug from the lungs. In those nanotechnology based drug delivery systems are being developed as a tremendous field. Nano refers to particles size range of 1-1000nm. An important feature of these technologies is the large geometric size of the particles than normal aerosol solutions, which makes it difficult for the lung macrophages to clear these particles. Therefore it results in longer residence times for the particles in the lungs after delivering the drug to the lungs. The present review discusses about the anatomy and structure of lungs, various conventional formulations for pulmonary delivery, and the various colloidal carriers like liposomes, dendrimers, nanoparticles, which involves the delivering of drugs to lungs.   Key words: targeted drug delivery, pulmonary drug delivery, nanotechnology, colloidal particles.

The worldwide CNS pathology incidence displayed that about 1.5 billion people suffer from CNS disorders. The worrying  fact that , delivering drugs to the CNS is impaired by the presence of the blood-brain barrier (BBB) that represents the main obstacle for CNS drug development, many hydrophilic drugs and neuropeptides etc are may have difficulty in crossing the blood-brain barrier. It is important to consider not only the net delivery of the agent to the CNS, but also the ability of the agent to access the relevant target site within the CNS. Many strategies have been developed to deliver the drug into brain by crossing the BBB are chemical delivery systems, magnetic drug targeting, or drug carrier systems such as antibodies, liposomes or Nanoparticles. Among those, Nanoparticles have got a great concentration as the potential targeted drug delivery systems in the brain recently. Nanoparticles (NP) are solid colloidal particles ranging in size from one to 1000nm that may be utilized as brain drug delivery carriers. Coating of Nanoparticles with drug molecules are as carriers to cross the BBB and transport the drugs to the specific sites in brain where they are needed.  NPs may provide slow drug release in blood and thereby reduces the peripheral toxicity. Key words: BBB, Drug delivery to brain, Nanotechnology, Colloidal drug carriers.