Absorption, drug gastrointestinal processes affecting

Fig. 2 Summary of processes involved following the oral administration of a drug in tablet or capsule form. (From Blanchard, J. Gastrointestinal absorption. II. Formulation factors affecting bioavailability. Am. J. Pharm. 1978, 150, 132-151.)...

Figure 8.10 Gastrointestinal tract with processes affecting drug absorption efficiency.

Figure 2.1 Oral drag absorption process from the gastrointestinal tract (GIT). Schematic depicting the three major processes (/a, / and /h) affecting absorption of drug from the site of administration to the systemic circulation, that is oral bioavailability, /a- fg, and /h can be estimated from the general relationship provided in Eq. 2.3 ...

Absorption is the transfer of a drug from its site of administration to the blood stream. The rate and efficiency of absorption depend on the route of administration. For intravenous delivery, absorption is complete, that is, the total dose of drug reaches the systemic circulation. Drug delivery by other routes may result in only partial absorption and thus lower bioavailability. For example, the oral route requires that a drug dissolve in the gastrointestinal fluid and then penetrate the epithelial cells of the intestinal mucosa disease states or the presence of food may affect this process. 

The gastrointestinal tract is the main site of action of acarbose, which is metabolized exclusively within the gastrointestinal tract, principally by intestinal bacteria this process may be adversely affected by antibiotics that alter the intestinal bacterial flora. Acarbose affects the absorption of some drugs (e.g. digoxin). 

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