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PharmD clinical pharmacy program Level 3, Semester 2 Biopharmaceutics & Pharmacokinetics (PT608(

CHAPTER SUMMARY

:
Factors affecting distribution
,
1. Differing characteristics of body tissues
,
2. Disease states that alter physiology
,
3. Physico-chemical and lipid solubility of the drug
4. Regional differences in physiologic pH (e.g., stomach and urine)

5. Extent of protein binding of the drug.

Clinical Significance

1. Drug displacement interactions

2. In hypoalbuminemia, binding may be reduced and high concentrations of free
drug may be attained e.g. Phenytoin and Furosemide.

3. Drugs that are highly plasma protein bound may have: a longer duration
of action and hence longer half-life because the drugs in bound form cannot

be metabolized or excreted. Thus, they require less frequent dosing.

Distribution to the Brain & Blood–Brain Barrier

Distribution from Mother to Fetus & Placental barrier

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