Nanometer

Forum

Nanotechnology provides striking promises, when applied to medical diseases like cancer, diabetes, or Alzheimer's disease, cardiovascular problems, infectious or inflammatory diseases. Improving the quality of life and health of citizens require further research on nanomedicine.

The inadequate improvement in the treatment of harsh diseases has led to the implementation of a multidisciplinary advancement to the target specific delivery and release of drugs. This received an impetus via nanoscience and nanotechnology. The latest drug delivery systems combine polymer science, bioconjugate chemistry and molecular biology. The main objective is to attain a control over pharmacokinetics and pharmacodynamics of the applied medicine, reduce the toxicity.

 The recent developments in drug delivery and targeting systems generally aspire to lower drug nastiness and failure, avoid detrimental side effects and amplify the drug-availability at the diseased site. Nanotechnology aims at engineering the drug carriers that include nanoparticles, nanocapsules, lipoproteins and liposomes, to slowly decay, respond to stimuli and be target-specific. The research of nanotechnology has lead to various developments of various targeting mechanisms. For example special build-up of chemotherapeutic agents in solid tumours resulting from the differences in the vascularization of the tumour tissue makes this property of vascularization nanoparticle specific. These particles use this property to target the diseased tissue. Another method known as active targeting involves a coating of the surface of drug carriers with the nano killers thus allowing them to get selectively adhered to problematic cells.

Nano-based approach to drug delivery deal with crossing a typical physical barrier such as the blood-brain barrier. The basic aim is to find different suitable routes for the release of the nano particles or protein-based drugs except for the gastro-intestinal tract route where the drugs are subjected to degradation. Thus nanotechnology form the basis of pioneering delivery techniques that provide many possible advantages to patients and also gives new definition to drug delivery system.

A result-oriented drug carrier system should show best possible drug release properties, refined targets and low toxicity. Nanoparticle dispersions constituting small particles of 10 - 300 nm diameter as well as colloidal systems, such as liquid crystal dispersions, hold a great future as carriers in drug delivery systems.

Dendrimers are nanometre-sized, polymer macromolecules. They have a central core and branching units. The core chemistry decides the solubilizing properties of the cavity within the core and the outer chemical groups determine the chemical behavior of the dendrimer itself. Certain linker to the outer surface of the dendrimer that allows it to bind to a particular disease site is a way to attain targeting.

Nanoparticles, nanospheres and nanocapsules that are amorphous or crystalline are efficiently used as drug carriers. They function by encapsulating or adsorbing a drug and provide protection against any kind of degradation. In nanocapsules, the basic drug is restricted to a cavity covered by a polymer membrane, in nanospheres, there is a matrix system in which the drug is scattered. The structures are formulated to provide a shield to the drug. The novel introduction of biodegradable polymeric nanoparticles has been a miracle in the sustained release of drugs that are target specific. This approach has also made nanoparticles the carriers of DNA in gene therapy and their capability to deliver proteins and genes via oral route.

Liposomes are vesicles that are formed of chemically active lipid bilayers and it is these bilayers that encapsulates the drug molecules and solubilize them within them. Moreover, certain proteins can be included in the liposome-membrane to act as filters and allow only the transmission of small solutes like ions, nutrients and antibiotics. Thus, liposome here acts as a natural nanocage for the drugs thus again protecting them from any kind of degradation. The transmission is also allowed when there is a concentration difference between the internal and the external walls of the nanocage.

Parenteral routes i.e. intravenous, intramuscular or subcutaneous routes are used for drug-administration. Liposomes are the nanosystems that are  administered intravenously. Other nanoscale drug carriers have a high ability for improving the drug-delivery through nasal and sublingual routes thus avoiding the initial metabolism and  accessing otherwise directly inaccessible area like brain and intra-articular cavities. The nasal route is now being used to administer the drug molecules with nanoparticles thus greatly improving the bioavailability of drugs.

Now a day pulmonary problem is increasing, they account for more than one third of the drug delivery market. Nanotechnology is now being used to make drug delivery efficient in the lungs. The drugs are delivered via various ways inhaler systems, aerosols, powder/capsule inhalers and nebulizers, which are now revised to contain nanostructures like dendrimers, micelles, nanoparticles and liposomes.  This route forms an effective route for delivering protein and peptide drugs. The lung-delivery will be a priority route for gene therapy when needed like in untreatable diseases of fibrosis treatment.

Moreover nanomedicines for pulmonary drug delivery are great at site- targeting for the respiratory disease treatments.

Transdermal drug delivery is another research field for nano delivery systems. It avoids troubles of gastrointestinal problems and the drug degeneration. Moreover, due to minimal meddling caused by the presence of food, the drug-delivery rate becomes more efficient. Moreover this procedure is non-invasive and is used for local drug delivery. Trans-tissue drug delivery systems are also becoming popular and need to be adhered to the resected tissue during surgery.

            The nanomedicine used produces an eminent pharmacological outcome and minimizes any toxicity that is associated with drug administration.

Thus use of nanotecnology to form an effective drug delivery system in order to minimize the drug-degradation as well as site targeting of drugs is gaining momentum.