Drug delivery systems are generally used for 'difficult drugs'; drugs with poor solubility that are difficult to get into the body directly to a specific site. Drugs can be micro-encapsulated (e.g. using liposomes) for injectable systems, which have slow release properties making the drugs more efficient.
In drug delivery systems, the drugs have to withstand the manufacturing processes of the particles. This may be difficult with certain fragile drugs. In these circumstances, the surface of the particles may have to be surface treated with the drugs.
The need for targeted drugs comes about from the possibility that they may have non-specific toxicities in certain areas of the body, for example many drugs build up in the liver and cause toxicity. In addition, the drugs may have poor bio-distribution and may only ever be present where they are needed in low and ineffectual doses.
Other alternatives for drug delivery involve the use of polymeric micelles (hydrophilic outer with hydrophobic centre which can be loaded with drug). Again they can be utilised to prevent accumulation in the liver and improve bio-distribution.
NanoSight Technology give drug delivery researchers the opportunity to visualise their systems, assess polydispersity and agglomeration, and to measure and record particle size distribution. DLS has problems in these systems because the refractive index of the particles needs to be known, and the lack of an overview image makes results on newly-developed systems hard to interpret.
NanoSight Technology provide a unique method of visualising and analysing particles in liquids and relate the rate of Brownian motion to particle size. The rate of movement is related only to the viscosity of the liquid, the temperature and size of the particle. The movement is not influenced by particle density. NanoSight LM10 and LM20 systems are capable of measuring particles between 10 nm (10 nm for silver, 25+ nm for most other materials) and 1,000 nm (1 micron). Particle & Surface Sciences distribute NanoSight Technology Systems throughout Australia and New Zealand.