Clinical evaluation, drugs stages

To set the stage, it is useful to put this topic in the larger context of the dramatically changing health care environment and its implications for drug research, development and clinical evaluation. 

A potential new drug candidate faces a well-defined clinical and product development process that has been refined over several decades. The development phase of a new dmg product usually consists of two main activities clinical evaluation (safety and efficacy), and product development (dmg substance and dosage form). As shown in Table 1.1, the process can last as long as 7-9.5 years and the cost can be approximately 50% of the entire expense for development of a new medicine.8 At this stage, some programs would be terminated for various reasons, such as lack of clinical efficacy, clinical toxicity, or dmg developability. 

Poisoning constitutes one of the commonest forms of medical emergency and is estimated to account for about 10% of all acute admissions to hospitals in Britain [486]. Identification of drugs or other toxic substances may be requested in assisting clinical evaluation or be required at a later stage for forensic purposes. Mass spectrometry and particularly GC-MS has been employed in both classes of analysis. 

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