Once detailed information of the disease has been recorded and the target identified, there are couple more stages for target identification. If the company are tackling an existing disease then the company will target either the same target as current drugs. If the disease target is new then the company should tackle the pathophysiology of the disease (new target protein). The current drug targets include enzymes, cell surface receptors GCPR, transporters and ion channels. The most common target is the enzyme and GCPR interaction. (Rang,2005) ( Seneci and Terstappen,2009)
After the target has been identified the company has to take steps into verifying if the target is correct, target validation. If this step is not completed correctly then the actual drug might not be as effective as first thought. Ways in which to complete this is firstly target validation on human tissue, measure the gene expression profiling the disease tissue, cellular localisation of target in normal and diseased tissue. Further methods include using blood samples to test function of targets, this is vital to check levels in humans as recombinant systems do not prove to show the exact expression of target and also the function maybe cell dependant. (Rang,2005)
Once the target has been validated and the company have decided to continue with the development, the next process of screening will occur. This primarily involves High Throughput Screening (HTS). This process involves a massive library of compounds tested against the target protein, i.e.
References: – Humphrey P. Rang , Drug Discovery and Development: Technology In Transition, 24 Nov 2005 Pierfausto Seneci and Georg C. Terstappen, Modern Drug Discovery: From Ideas to Clinical Candidates, 6 Mar 2009