Pharmacokinetics advantages/disadvantages

The major advantage of an in vitro system is that it represents a simplified system which allows the experimenter to address questions which cannot be tested in vivo. These systems can allow analysis of activation or metabolism at the single enzyme level. They can test proposed pathways of metabolism or activation. Such studies are not practical with in vivo systems. The major disadvantage is that in vitro systems are a simplified system and the results can be easily over-interpreted. In vitro systems cannot model the pharmacokinetics or toxicokinetics of xenobiotic exposure in vivo. In addition, there may be other, unappreciated enzymes or factors which influence metabolism/toxicity in vivo which are not present in the in vitro system. 

The definitions and statistical theory of PPK, advantages, and disadvantages of PPK have been discussed in this chapter. Models, data type, methods, and software programs for estimating population pharmacokinetic parameters, design, and analysis of population pharmacokinetic studies have been reviewed, as well as its application in biopharmaceutics. The use of population methods continues to increase while there is a shortage of those who can implement the approach. 

TR Browne. Stable isotopes in clinical pharmacokinetic investigations advantages and disadvantages. Clin Pharmacokinet 18 423-433,1990. 

Table 5.3 Advantages and disadvantages of detailed pharmacokinetic studies in small groups of specific patients - the traditional approach...

The pharmacokinetic window design has many variants. One variant is where each subject is sampled twice on each visit. The subject comes to the clinic, has a blood sample drawn at predose, the next dose is taken, the subject remains at the clinic for some time, and then a second sample is collected after a period of time has expired. The disadvantage of this approach is that it requires the subject to remain at the clinic, which places an extra burden both on the subject and on the site in collecting the sample. The advantage of this design is that the quality of the dosing times and sample collection... 

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