Sites of drug administration

Sites of drug administration are classified into two categories  

Important features of the intravascular route of drug administration 

The entire administered dose is available to produce pharmacological effects. 

This route is used more often in life-threatening situations. 

Adverse reactions are difficult to reverse or control accuracy in calculations and administration of dmg dose, therefore, are very critical. 

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The major limitation to developing therapeutic proteins in nonparenteral dosage forms is the poor permeability of these water-soluble and hygroscopic macromolecules across the tissue layers at the site of drug administration. These tissue layers include the epithelium of the gastrointestinal tract, the stratum corneum of the skin, and the epithelium lining of the alveoli and nasal cavity. 

On the other hand, polycyclic aromatic compounds given orally or subcutaneously are more likely to cause aplastic anemia, leukemia, and lymphatic tumors in Ah-nonresponsive mice. These effects are manifest in tissues distant from the site of drug administration. In the example of oral benzo[a]pyrene, pharmacokinetic studies have shown a 10-and 20-fold higher uptake in the marrow and spleen of Ah-nonresponsive than of Ah-responsive mice this confirms the phenomenon called "first-pass elimination kinetics."... 

The mathematical formulation of the PBPK model is dependent on several factors routes of intake of a chemical or sites of drug administration, target tissues of interest, physiological components to be explicitly modeled (kinetically important tissues and organs and the linkages between them), transport processes of the chemical (flow, diffusion, disposition, clearance, etc.), and metabolic processes involved. 

Drug response, whether therapeutic or toxic, is dictated by drug concentration at sites of action located outside the site of drug administration. Thus, tissue distribution can often be a critical determinant of drug action, and is a complex process that involves drug transport across biological membranes into the blood, and distribution to sites of action or storage and eventually to sites of elimination. 

Compared with other routes of administration, different mucosa that line the oral cavity (buccal and sublingual sites of drug administration) offer advantages that include (1) being noninvasive, (2) producing a rapid onset of action,... 

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